The heart is a muscular organ about the size of a fist, located just behind and slightly left of the breastbone. The heart pumps blood through the network of arteries and veins called the cardiovascular system.

The human heart has four chambers:

Right atrium receives blood from the veins and pumps it to the right ventricle.

Right ventricle receives blood from the right atrium and pumps it to the lungs, where it is loaded with oxygen.

Left atrium receives oxygenated blood from the lungs and pumps it to the left ventricle. The left ventricle (the strongest chamber) pumps oxygen-rich blood to the rest of the body.

Left ventricle’s vigorous contractions create our blood pressure.

The coronary arteries run along the surface of the heart and provide oxygen-rich blood to the heart muscle. A web of nerve tissue also runs through the heart, conducting the complex signals that govern contraction and relaxation. Surrounding the heart is a sac called the pericardium.

The upper chambers (right and left atria) and the lower chambers (right and left ventricles) work with your heart's electrical system to keep your heart beating at an appropriate rate — usually 60 to 100 beats a minute for adults at rest.

Your heart's electrical system controls your heartbeat, beginning in a group of cells at the top of the heart (sinus node) and spreading to the bottom, causing it to contract and pump blood.

Certain conditions can cause the blood flow too slowly, making it difficult for the body to receive necessary oxygen and nutrients. Angioplasty is a procedure used to restore blood flow through the patient’s arteries. It restores blood flow to the heart muscle without open-heart surgery. Angioplasty opens up the blocked artery so blood can flow smoothly. For angioplasty, a long, thin tube (catheter) is put into a blood vessel and guided to the blocked coronary artery. The catheter has a tiny balloon at its tip. Once the catheter is in place, the balloon is inflated at the narrowed area of the heart artery. This presses the plaque or blood clot against the sides of the artery, making more room for blood flow.

Surgery to repair or replace aortic aneurysms and aortic dissections. The surgeon removes a section of the body's largest blood vessel (aorta) your aortic valve. The section of your aorta is replaced with an artificial tube (graft), and your aortic valve is replaced with a mechanical or biological valve.

Surgery to repair or replace an aortic valve that is not working correctly.

Aortic valve surgery, which includes an aortic valve replacement, or an aortic valve repair, fixes an aortic valve that isn't working correctly. The aortic valve lets blood flow from the left lower chamber of the heart (left ventricle) to the aorta, which is the body's main blood vessel. The aorta distributes blood throughout the body.

When do aortic valves need to be repaired or replaced?

Aortic valves help pump blood out of the heart to the rest of the body. In a person with aortic valve disease, the aortic valve has a malfunction:

Regurgitation: The aortic valve doesn't close completely, causing blood to flow backward instead of forward through the valve.

Stenosis: The aortic valve opening doesn't form properly or becomes narrow, inhibiting the flow of blood out of the chambers of the heart. When this happens, the heart is forced to pump blood with increased force in order to move blood through the stiff (stenotic) valve.

Aortic valves can have regurgitation and stenosis at the same time.

When heart valves fail to open and close properly, the heart can become damaged. Heart valve problems are one cause of heart failure.

In this surgery the surgeon will use an artificial valve to replace your poorly working valve. This will ensure that your blood can exit the heart and flow out to the body normally. The surgery is called "open" because it uses a traditional type of incision to expose your heart. This incision is larger than those in minimally invasive types of aortic valve replacement surgery.

A surgical procedure to correct irregular heart rhythms such as atrial fibrillation or ventricular tachycardia.

Ablation: there are several reasons for this surgery. If you are having ablation for atrial fibrillation, small scars are intentionally created to break up the electrical signals that cause the irregular heartbeats in a condition known as atrial fibrillation. During catheter ablation, small areas of tissue that may be causing the arrhythmia are destroyed.

Coronary artery bypass graft surgery (CABG) is a procedure used to treat coronary artery disease in certain circumstances. Coronary artery disease (CAD) is the narrowing of the coronary arteries (the blood vessels that supply oxygen and nutrients to the heart muscle), caused by a build up of fatty material within the walls of the arteries.

This build up causes the inside of the arteries to become rough and narrowed, limiting the supply of oxygen-rich blood to the heart muscle.

One way to treat the blocked or narrowed arteries is to bypass the blocked portion of the coronary artery with another piece of blood vessel. Blood vessels, or grafts, may be pieces of a vein that are then grafted above and below the blocked area of a coronary artery, allowing blood to flow around the obstruction. Veins are usually taken from the leg, but arteries from the chest may also be used to create a bypass graft.

One end of the graft is attached above the blockage and the other end is attached below the blockage. Thus, the blood is rerouted around, or bypasses, the blockage through the new graft to reach the heart muscle.

This bypass of the blocked coronary artery can be done by performing coronary artery bypass surgery.

Traditionally, in order to bypass the blocked coronary artery in this manner, the chest is opened in the operating room and the heart is stopped for a time so that the surgeon can perform the bypass. In order to open the chest, the breastbone (sternum) is cut in half and spread apart.

Once the heart is exposed, tubes are inserted into the heart so that the blood can be pumped through the body during the surgery by a cardiopulmonary bypass machine (heart-lung machine). The bypass machine is necessary to pump blood while the heart is stopped and kept still in order for the surgeon to perform the bypass operation.

While the traditional "open heart" procedure is still performed and often preferred in many situations, newer, less invasive techniques have been developed to bypass blocked coronary arteries.

"Off-pump" procedures, in which the heart does not have to be stopped, were developed in the 1990's. Other minimally-invasive procedures, such as key-hole surgery (performed through very small incisions) and robotic procedures (performed with the aid of a moving mechanical device), are also in development.

• Single bypass. Only one artery is blocked.

• Double bypass. Two arteries are blocked.

• Triple bypass. Three arteries are blocked.

• Quadruple bypass. Four arteries are blocked.

A heart transplant is surgery to remove the diseased heart from a person and replace it with a healthy one from an organ donor. To remove the heart from the donor, two or more healthcare providers must declare the donor brain-dead.

Cardiologists and cardiac surgeons will first try to manage heart failure through medications or electrical devices. However, when the heart failure becomes severe, the patient might need a new heart. Heart transplant surgery is the process of replacing a diseased heart with a healthy donor heart.

When a donor heart becomes available for the patient, the transplant process begins. An incision will be made in the midline of the patient’s chest.

A heart-lung bypass machine will take over the work of the patient’s heart and lungs. While this is occurring another team of surgeons will travel to the donor's hospital. Once there, the team will examine the donor's heart to make absolutely certain that it is a suitable match.

Once the donor team arrives with the patient’s new heart the diseased heart will be removed and replaced with the healthy donor organ. The operation usually lasts between five and six hours, but can last longer if there has been a previous open-heart surgery or if a left ventricular assist device is in place.

Heart transplant patients will need medications for the rest of their lives to keep their bodies from rejecting their new heart.

Heart valve surgery used to repair or replace diseased heart valves.

There are four heart valves that open and close to regulate blood flow through the heart. Heart valve surgery treats diseases and defects of these valves of the heart.

There are two main types of heart valve surgery:

• Surgery to replace faulty heart valves

• Surgery to repair faulty heart valves

• Types of Heart Valve Malfunction

There are four valves of the heart:

• Mitral valve

• Aortic valve

• Tricuspid valve

• Pulmonary valve

Heart disease can affect any of the four valves of the heart. Most commonly, it affects the mitral and aortic valves. Some types of heart valve disease are congenital and other types develop over time.

There are two common types of heart valve malfunction:

• Regurgitation: The valve(s) does not close completely, causing the blood to flow backward instead of forward through the valve.

• Stenosis: The valve(s) opening becomes narrowed or does not form properly, inhibiting the flow of blood out of the ventricle or atria. The heart is forced to pump blood with increased force in order to move blood through the stiff (stenotic) valve(s).

Heart valves can have one type of malfunction or have both types of valve malfunctions at the same time.

Traditionally, open-heart surgery is used to repair or replace heart valves. This means that a large incision is made in the chest and the heart stopped for a time so that the surgeon can repair or replace the valve(s). Newer, less invasive techniques have been developed to replace or repair heart valves. Minimally invasive procedures make smaller incisions, and mean less pain afterward and shorter hospital stays.

The diseased valve may be repaired using a ring to support the damaged valve, or the entire valve may be removed and replaced by an artificial valve. Artificial valves may be made of carbon coated plastic or tissue (made from animal valves or human valves taken from donors).

This surgery involves insertion of a mechanical pump (LVAD) which aids in the pumping function of the blood. A LVAD helps the left ventricle (main pumping chamber of the heart) pump blood to the rest of the body.

LVADs can be used as:

• Bridge-to-transplant therapy: This is a life-saving therapy for patients awaiting a heart transplant. Patients use the LVAD until a heart becomes available. In some cases, the LVAD is able to restore the failing heart, eliminating the need for a transplant.

• Destination therapy: Some patients are not candidates for heart transplants. In this case, patients can receive long-term treatment using an LVAD, which can prolong and improve patients' lives.

Cardiac surgeons have now invented new ways to implant LVADs that avoid splitting the breast bone. Unlike in the past, LVAD devices are now portable. This means patients can continue their normal activities while waiting for a donor heart to become available. In order to receive an LVAD; a number of tests to determine that

Percutaneous transluminal coronary angioplasty (PTCA) is performed to open blocked coronary arteries caused by coronary artery disease (CAD) and to restore arterial blood flow to the heart tissue without open-heart surgery.

A special catheter (long hollow tube) is inserted into the coronary artery to be treated. This catheter has a tiny balloon at its tip. The balloon is inflated once the catheter has been placed into the narrowed area of the coronary artery.

The inflation of the balloon compresses the fatty tissue in the artery and makes a larger opening inside the artery for improved blood flow.

A pacemaker is implanted to help control your heartbeat. Sometimes a pacemaker may be temporary if the patient has a slow heartbeat (bradycardia) after a heart attack surgery or medication overdose but the hearts beat is otherwise expected to recover. A pacemaker may be implanted permanently to correct a chronic slow or irregular heartbeat or to help treat heart failure.

Pacemakers work only when needed. If your heartbeat is too slow (bradycardia), the pacemaker sends electrical signals to your heart to correct the beat.

Some newer pacemakers also have sensors that detect body motion or breathing rate and signal the devices to increase heart rate during exercise, as needed.

A pacemaker has two parts:

• Pulse generator. This small metal container houses a battery and the electrical circuitry that controls the rate of electrical pulses sent to the heart.

• Leads (electrodes). One to three flexible, insulated wires are each placed in one or more chambers of the heart and deliver the electrical pulses to adjust the heart rate. However, some newer pacemakers don't require leads. These devices, called leadless pacemakers, are implanted directly into the heart muscle.

The name of this condition can be a little confusing. When you have heart failure it doesn't mean your heart stops beating. What's really going on is that your heart can't pump blood as well as a healthy one.

The chambers of your heart may respond by stretching to carry more blood to pump through your body. They may become stiffer and thicker. This helps keep blood moving for a while, but in time, your heart muscle walls may get weaker.

Your kidneys react by causing your body to hold on to water and salt. Fluid may start to build up in your arms, legs, ankles, feet, lungs, or other organs.

There are roughly four stages of heart failure to help people understand how the condition changes over time and the kinds of treatments that are used for each.

Heart failure can be brought on by many conditions that damage the heart.

Coronary artery disease is a problem with the arteries that supply blood and oxygen to your heart. It means less blood flows to your heart muscle. When the arteries narrow or get blocked, your heart becomes starved for oxygen and nutrients and can't pump as well.

Heart attack may happen when a coronary artery is blocked suddenly, which stops the flow of blood to your heart muscle.

Cardiomyopathy is damage to your heart muscle. It can be caused by artery or blood flow problems, infections, and alcohol and drug abuse. Other diseases or genetic issues can also bring it on. Make sure your doctor knows your family's health history.

Conditions that overwork the heart include things like high blood pressure, heart valve disease, thyroid disease, kidney disease, diabetes, or heart defects you've had since you were born.

Systolic heart failure happens when your heart muscle doesn't squeeze with enough force. When that's the case, it pumps less oxygen-rich blood through your body.

Diastolic heart failure, your heart squeezes normally, but the ventricle (the main pumping chamber) doesn't relax properly. Less blood can enter your heart, and the blood pressure in your lungs goes up. When that happens, you get fluid in your lungs, legs, and belly.

This is the period when you're more likely to get heart failure. You may be in this stage if you have:

• High blood pressure

• Diabetes

• Coronary artery disease

• Metabolic syndrome

Your chances are also greater when you have a history of:

• Cardiotoxic drug therapy

• Alcohol abuse

• Rheumatic fever

• Family members with cardiomyopathy

Your doctor will probably recommend regular exercise and that you stop drinking alcohol, smoking, and using illegal drugs. You'll want to take steps to lower high blood pressure or high cholesterol.

If you have high blood pressure or had a heart attack, your doctor may prescribe beta-blockers.

When you have diabetes, high blood pressure, or other heart and blood vessel conditions like coronary artery disease, you may need to take an ACE inhibitor or an angiotensin II receptor blocker (ARB).

You're in this phase if you never had symptoms of heart failure you're diagnosed with systolic left ventricular dysfunction, which means the left chamber of your heart doesn't pump well. You may be in this group if you had or have:

• Heart attack

• Valve disease

• Cardiomyopathy

Treatment will depend on your situation. Your doctor may suggest an ACE inhibitor or angiotensin II receptor blocker (ARB), or beta-blockers after a heart attack. They may add an aldosterone inhibitor if your symptoms continue while you're taking beta-blockers and ACE/ARB medications.

Surgery can repair coronary arteries and valves, or valves which may need to be replaced. Sometimes an implantable cardiac defibrillator (ICD) will help.

You're in this phase if you have systolic heart failure along with symptoms such as:

• Shortness of breath

• Fatigue

• Less ability to exercise

Your doctor may prescribe:

• ACE inhibitors and beta-blockers

• Angiotensin receptor blocker and neprilysin inhibitors

If your symptoms don't go away, you may need to take:

• Hydralazine/nitrate combination

• Diuretics (water pills) and digoxin

• Aldosterone inhibitor, when your symptoms stay severe with other treatments

• Soluble Guanylate Cyclase (sGC) stimulators

Devices such as a biventricular pacemaker or implantable cardiac defibrillator (ICD) may help.

You may need to change some things about your day-to-day life, too:

• Eat less salt.

• Lose weight if you're overweight.

• Drink fewer fluids if necessary.

• Stop drugs that make your condition worse.

You're in this phase if you have systolic heart failure and advanced symptoms after you get medical care.

Some of the treatments from stages A, B, and C will help stage D, too. Your doctor may also discuss:

• Heart transplant

• Ventricular assist devices

• Surgery options

• Continuous infusion of intravenous inotropic drugs

Permanent disruption of a problematic electric pathway in the heart with a heated catheter.

Exercise which raises the heart rate and can both improve your functional ability and, in some cases, reduce symptoms of heart disease. It is repetitive in nature and involves the large muscle groups. Examples are walking, swimming, and cycling.

Small portable electrocardiograph machines that are able to record the heart's rhythm. Each type of monitor has unique features related to length of recording time and ability to send the recordings over the phone. Types of ambulatory monitors include: Holter Monitor, Loop Recorder, Event Monitor, and Transtelephonic transmitter.

A condition characterized by a deficiency of red blood cells Anaemia reduces the amount of oxygen available to the body.

A sac formed by the bulging of a blood vessel wall or heart tissue. When aneurysms grow too large, they can rupture, and the bleeding can be life threatening. Aneurysms that have grown too large should be repaired.

Discomfort or pressure, usually in the chest, caused by a temporarily inadequate blood supply to the heart muscle, usually due to atherosclerosis (see below) or blockages in the arteries. Discomfort may also be felt in the neck, jaw, or arms.

The spontaneous or drug-induced growth of new blood vessels. The growth of these vessels may help to alleviate coronary artery disease by rerouting blood flow around clogged arteries.

A test used to diagnose heart disease. During the procedure, a catheter is inserted into an artery, usually in the leg or wrist, and contrast dye is injected into the arteries and heart. X-rays of the arteries and heart are taken.

An invasive procedure, during which a specially designed balloon catheter with a small balloon tip is guided to the point of narrowing in the artery. Once in place, the balloon is inflated to compress the fatty matter and plaque into the artery wall and stretch the artery open to increase blood flow to the heart.

A group of drugs used to treat high blood pressure and heart failure. ACE inhibitors block a specific enzyme (ACE or angiotensin-converting enzyme) that retains salt in the kidney and can cause heart and blood pressure problems. ACE inhibitors have been shown to decrease the risk of dying from a heart attack and to improve heart function.

A ring of tough fibrous tissue that is attached to and supports the leaflets of the heart valve.

The normal anatomy for the coronary arteries involves their origin from the aorta at each of two separate sites. People can be born with the origin of a coronary artery that comes from an abnormal site, and this can lead to problems of coronary ischemia, which can subsequently lead to a heart attack. Not all coronary anomalies need surgery, but some do, and the specific operation depends on which of the many varieties of coronary anomalies is present.

A drug that is used to treat abnormal heart rhythms.

A medication that prevents blood from clotting; used for people at risk for atrial fibrillation, stroke, or blood clots.

A medication used to treat high blood pressure.

Large artery leaving the heart. All blood pumped out of the left ventricle travels through the aorta on its way to other parts of the body.

Aortic insufficiency refers specifically to the aortic valve, which is the valve the blood passes through as it leaves the heart and enters the aorta. When blood leaks back through the valve, it is known as aortic insufficiency. Small amounts of aortic insufficiency may be inconsequential, but larger amounts require repair or replacement of the aortic valve.

The aortic valve is the last valve through which the blood passes before it enters the aorta or main blood vessel of the body. The valve's role is to prevent blood from leaking back into the left ventricle from the aorta after it has been ejected from the heart.

When the aortic valve is diseased, it can become either stenotic (too narrow) or insufficient (leaky). In such cases, the aortic valve may need to be replaced with either a prosthetic or human valve. There are other types of valves used such as from a pig or cow; the type of valve replacement depends on the person's case. Transcatheter aortic valve replacement (TAVR) is a minimally invasive procedure to replace an aortic valve that can't fully open because of stenosis.

When replacement of an aortic valve is necessary, it is possible to replace the valve with another human valve known as an aortic valve homograft. This operation requires a cardiopulmonary bypass machine.

The aortic valve is the last valve in the heart through which the blood travels prior to circulating in the body. When this valve is leaking or too tight, a surgeon may be able to repair the valve rather than replace it.

An arrhythmia is an irregular heartbeat. It means your heart is out of its usual rhythm.

It may feel like your heart skipped a beat, added a beat, or is "fluttering." It might feel like it’s beating too fast (which doctors call tachycardia) or too slow (called brachycardia). Or you might not notice anything.

Arrhythmias can be an emergency, or they could be harmless. If you feel something unusual happening with your heartbeat, get medical help right away so doctors can find out why it's happening and what you need to do about it.

What Are the Symptoms of Arrhythmia?

An arrhythmia can be silent, meaning you don't notice any symptoms. Your doctor may spot an uneven heartbeat during a physical exam.

In patients who require coronary artery bypass graft surgery, it is sometimes desirable to use arteries from other parts of the body to provide the bypass grafts. This is known as arterial grafting. The alternative is to use vein grafts for coronary bypass surgery.

Blood vessels that carry blood away from the heart.

This rare procedure is used to clean out clogged heart arteries. A DCA catheter has a hollow cylinder on the tip with an open window on one side and a balloon on the other. When the catheter is inserted into the narrowed artery, the balloon is inflated, pushing the window against the fatty matter clogging the vessel. A blade (cutter) within the cylinder rotates and shaves off any fat that has protruded into the window. The shavings are caught in a chamber within the catheter and removed. This process is repeated as needed to allow better blood flow.

The process whereby abnormal deposits of lipids, cholesterol, inflammatory cells, and plaque build up lead to coronary artery disease and other cardiovascular problems. You may have heard the term “hardening and narrowing of your arteries” – this is what atherosclerosis is. It can put blood flow at risk as your arteries become blocked.

You might also hear it called arteriosclerosis or atherosclerotic cardiovascular disease – it’s the same thing and it’s the usual cause of heart attacks, strokes, and peripheral vascular disease -- what together are called cardiovascular disease.

In patients who require coronary artery bypass graft surgery, it is sometimes desirable to use arteries from other parts of the body to provide the bypass grafts. This is known as arterial grafting. The alternative is to use vein grafts for coronary bypass surgery.

Blood vessels that carry blood away from the heart.

Total Artificial Heart (TAH): Essentially, an artificial heart is a blood pump. Dr Chang saw it as a standard piece of surgical equipment that should, one day, be available in all cardiac units. It could also be used for transplant patients while they waited for a suitable donor heart. The TAH is intended for patients with imminent heart failure who are awaiting heart transplantation. It also has a temporary function for those with hearts that need time to recover their pumping power. The TAH can either be implanted in a patient’s body or used externally.

A quivery, fluttery heartbeat.

You might also hear the doctor call it arrhythmia. It means your heart’s normal rhythm is out of whack. Because your blood isn't moving well, you're more likely to have heart failure. That's when your heart can't keep up with your body’s needs. Blood can also pool inside your heart and form clots. If one gets stuck in your brain, you can have a stroke.

What happens in AFib? Normally, the top part of your heart (the atria) squeezes first, then the bottom part (the ventricles). The timing of these contractions is what moves the blood. When you have AFib, the electrical signals that control this process are off-kilter. Instead of working together, the atria do their own thing.

An artificial heart valve is a one-way implanted valve placed into a person's heart to replace a heart valve that is not functioning properly (valvular heart disease). Artificial heart valves can be separated into three broad classes: mechanical heart valves, bioprosthetic tissue valves and engineered tissue valves. Dr Victor Chang designed both a tissue valve and a mechanical valve – both named after St Vincent’s Hospital in Sydney.

A congenital condition (present at birth). A mix of problems affecting the centre of the heart. Children born with this condition have a hole in the wall between the heart's chambers. They also have problems with the valves that control blood flow in the heart.

A congenital condition (present at birth) where there is a hole in the heart between the upper chambers (atria). The hole increases the amount of blood that flows through the lungs and forces the heart to work too hard, causing the heart muscle to grow larger.

Small atrial septal defects might be found by chance and never cause a concern. Others close during infancy or early childhood.

A large, long-term atrial septal defect can damage the heart and lungs. Surgery may be needed to repair an atrial septal defect and to prevent complications.

A group of special cells located near the center of the heart that helps to regulate the heart rhythm. Here, the electrical current slows for a moment before going on to the ventricles.

The top chamber of the heart. There are two atria -- the left and the right, divided by a muscular wall, called the septum. The atrium contracts before the ventricle to allow optimal filling of the ventricle.

A procedure used to clean out clogged heart arteries. A specially designed balloon catheter with a small balloon tip is guided to the point of narrowing in the artery. Once in place, the balloon is inflated to compress the fatty matter and plaque into the artery wall and stretch the artery open to increase blood flow to the heart.

During this surgical procedure to treat heart failure, the surgeon cuts out a piece of the patient's enlarged left ventricular muscle. The intention is to reduce the size of the left ventricular cavity, improve left ventricular function, and reverse congestive heart failure. This procedure is not successful in the long term, but it has led to better surgical techniques to treat those with heart failure (see infarct exclusion surgery).

A drug that slows heart rate, lowers blood pressure, controls angina, helps regulate arrhythmias, and protects patients with prior heart attacks from future heart attacks. It increases the time that the heart can fill with blood, and therefore decreases the amount of work the heart needs to do.

A congenital condition (present at birth) where there is a bicuspid valve (three leaflets instead of the normal three); backward flow because the valve may not close tightly or enlarged aorta. A genetic condition.

The force exerted in the arteries by blood as it circulates. It is divided into systolic (when the heart contracts) and diastolic (when the heart is filling) pressures.

What Systolic, Diastolic Blood Pressure Numbers Mean?

When you get your blood pressure numbers, there are two of them. The first, or “top” one, is your systolic blood pressure. The second, or “bottom,” one is diastolic blood pressure.

Knowing both is important and could save your life.

What Does the Systolic Blood Pressure Number Mean?

When your heart beats, it squeezes and pushes blood through your arteries to the rest of your body. This force creates pressure on those blood vessels, and that's your systolic blood pressure.

Here’s how to understand your systolic blood pressure number:

• Normal: Below 120

• Elevated: 120-129

• Stage 1 high blood pressure (also called hypertension): 130-139

• Stage 2 hypertension: 140 or more

• Hypertensive crisis: 180 or more. Call 000

What Does the Diastolic Blood Pressure Number Mean?

The diastolic reading, or the bottom number, is the pressure in the arteries when the heart rests between beats. This is the time when the heart fills with blood and gets oxygen.

This is what your diastolic blood pressure number means:

• Normal: Lower than 80

• Stage 1 hypertension: 80-89

• Stage 2 hypertension: 90 or more

• Hypertensive crisis: 120 or more. Call 000.

Slow heart beat. Generally, it is normal to have a slower heart rate when you’re resting. It can be a sign of good health. But if it’s too slow, it could be a symptom of a condition called bradycardia.

Normally, your heart beats 60 to 100 times a minute when you’re at rest. But with bradycardia, it goes down to less than 60 beats a minute.

This might not cause a problem for some people. But it could be a clue that you have an issue with the electrical system in your heart. You need to see a doctor who can figure out why it’s beating slowly and if you should get treatment.

Part of the electrical pathway of the heart that delivers electrical impulses to the ventricles of the heart. The bundle divides or branches into a right bundle and the left bundle. The bundles take the impulse through the ventricles (bottom chambers) to cause them to contract.

Normally, the electrical impulse travels down both the right and left bundle branches at the same speed and the ventricles contract at the same time. If there is a block in one of the branches, it's called a bundle branch block. A bundle branch block causes one ventricle to contract just after the other ventricle and may be a sign of heart damage.

A drug that reduces spasm of the blood vessels, lowers blood pressure, and controls angina; acts by selectively blocking the uptake of calcium by the cells.

Tiny blood vessels connecting arteries to veins. These blood vessels carry oxygen and nutrients to individual cells throughout the body.

When the heart stops beating suddenly and respiration (breathing) and other body functions stop as a result.

A procedure used to diagnose heart disease. During the procedure, a catheter (inserted into an artery in your arm or leg) is guided to your heart, contrast dye is injected, and X-rays of the coronary arteries, heart chambers, and valves are taken. Its main function is to look for blockages in the arteries. This procedure also measures the pressures in the heart chambers to help diagnose the causes of heart failure and to see the significance of valve problems.

The amount of blood pumped by the heart each minute.

A structured program of education, nutrition, exercise, and activity guided toward lifestyle modification, increasing functional capabilities, and peer support.

Doctor specializing in the diagnosis and treatment of heart disease.

Abnormal heart condition in which the heart is dilated (poor pumping power and enlarged), restrictive (impaired ability of the heart to fill), or hypertrophic (a thickened heart). Fiona Coote has cardiomyopathy which was the reason for her heart transplant.

A technique designed to temporarily circulate oxygenated blood through the body of a person whose heart has stopped. It involves assessing the airway; if necessary, breathing for the person by mouth to mouth resuscitation or placing a tube into the breathing tube (trachea) and administering oxygen; determining if the person is without a pulse; and if necessary, applying compression to the chest to circulate blood.

Relates to the heart and blood vessels.

A procedure used to convert an irregular heart rhythm to a normal heart rhythm by applying electric shock or using certain medications.

A slender, hollow, flexible tube.

Chang Heart Assist Device.

The chordae tendineae (tendinous cords), colloquially known as the heart strings, are inelastic cords of fibrous connective tissue that connect the papillary muscles to the tricuspid valve and the mitral valve in the heart. The chordae tendineae connect the valves to the heart muscle.

An abnormality where the ends of the fingers and toes enlarge and the nails curve; often it is related to an inadequate oxygen-rich blood supply. However, it can be hereditary and completely normal. It is often seen with congenital heart defects, but is most often present because of other conditions such as severe lung disease.

A congenital condition (present at birth). A severe narrowing of the aorta, causing a decrease in blood flow to the lower part of the body. It forces the heart to pump harder to move blood through the aorta

Small capillary-like branches of an artery that form over time in response to narrowed coronary arteries. The collaterals "bypass" the area of narrowing and help to restore blood flow. However, during times of increased exertion, the collaterals may not be able to supply enough oxygen-rich blood to the heart muscle.

A surgical or catheter procedure that helps to repair the damage caused by defective heart valves. In some patients, specifically those with rheumatic (affect your joints tendons, ligaments, bones, and muscles) heart disease, this area of the heart (also called the commissures) can become scarred and the valve leaflets fail to open and allow blood to flow through easily. In this surgery, the commissures can be released or reopened.

A heart defect is a problem with the structure of the heart that a child is born with. Some congenital heart defects in children are simple and don't need treatment. Other congenital heart defects in children are more complex and may require several surgeries performed over a period of several years.

A condition where the heart muscle weakens and can't pump blood efficiently throughout the body. This is called systolic heart failure. Another type of congestive heart failure is due to lack of relaxation of the heart muscle causing fluid to be forced into the lungs, abdomen, and legs. This type is called diastolic heart failure.

The pericardium is the sac around the heart. In people with constrictive pericarditis, this sac becomes inflamed and scarred leading to shrinkage of the pericardium. This can prevent the heart from filling to its full extent.

Network of blood vessels that branch off the aorta to supply the heart muscle with oxygen-rich blood. There are two main coronary arteries: the right and the left. The left splits into two arteries called the circumflex and the left anterior descending (LAD) arteries, thus, the heart is often considered to have three major coronary arteries.

A build-up of fatty material in the wall of the coronary artery that causes narrowing of the artery.

Repeated contractions and dilations of the coronary arteries, causing a lack of blood supply to the heart muscle. It may occur at rest and can even occur in people without significant coronary artery disease.

A machine that is used to administer an electric shock to the heart in order to re-establish normal heart rhythm.

The pressure of the blood in the arteries when the heart is filling. It is the lower of two blood pressure measurements (for example, 120/80, where 80 is the diastolic pressure).

A disease of the myocardium (heart muscle) that causes the heart cavity to become stretched and enlarged and the pumping capacity of the heart to be reduced.

The increase in size of a blood vessel or heart chamber.

If you are unable to exercise on a treadmill or stationary bicycle for a stress test, a medication can be used instead of exercise to dilate the arteries in order to assess the heart's blood flow and look for areas of blockages.

A procedure that involves infusing a medication (dobutamine) through an intravenous (IV) line while you are closely monitored. This drug stimulates your heart, allowing evaluation of heart and valve function at rest and with exertion, when you are unable to exercise on a treadmill or stationary cycle.

Echocardiography is an imaging procedure that creates a graphic outline of the heart's movement, valves and chambers using high-frequency sound waves that come from a hand held wand placed on your chest.

Double-outlet Right Ventricle: A congenital condition (present at birth). The two large blood vessels don't connect to the heart normally. In this condition, the main artery that carries blood from the heart to the body (aorta) and the artery that directs blood from the heart to the lungs (pulmonary artery) connect partially or completely to the right lower heart chamber (ventricle). Sometimes these blood vessels are also reversed from their normal positions.

Difficulty breathing or shortness of breath.

A congenital condition (present at birth). The tricuspid valve is in the wrong position and the valve's flaps (leaflets) are malformed. As a result, the valve does not work properly. Blood might leak back through the valve, making the heart work less efficiently. Ebstein anomaly can also lead to enlargement of the heart and heart failure.

An imaging procedure that creates a moving picture outline of the heart's valves and chambers using high-frequency sound waves that come from a handheld wand placed on your chest or passed down your throat. Echo is often combined with Doppler ultrasound and colour Doppler to evaluate blood flow across the heart's valves. Doppler senses the speed of sound and can pick up abnormal leakage or restriction of the valves.

A congenital condition (present at birth). A long-term, life threatening complication of an unrepaired heart problem where there is an irregular blood flow in the heart and lungs. This causes the blood vessels in the lungs to become stiff and narrow. Blood pressure rises in the lungs' arteries (pulmonary arterial hypertension). Eisenmenger syndrome permanently damages the blood vessels in the lungs.

The amount of blood pumped out of a ventricle during each heartbeat. The ejection fraction evaluates how well the heart is pumping.

The EKG records on graph paper the electrical activity of the heart using small electrode patches attached to the skin.

An EP study is a test that evaluates the electrical activity within your heart. This test is used to help your doctor find out the cause of your rhythm disturbance and the best treatment for you. During the test, your doctor may safely reproduce your abnormal heart rhythm, then give you medications to see which one controls it best.

An infection of the inner lining of the heart or its valves. It is usually caused by bacteria and is more likely to occur in people who have heart valve defects or have had heart surgery to treat valve disease.

A treatment for those with symptomatic coronary artery disease (also called refractory angina), who are not eligible for standard treatments of revascularization (such as heart bypass surgery). During EECP, cuffs wrapped around the calves, thighs, and buttocks are inflated and deflated, gently but firmly compressing the blood vessels in the lower limbs, increasing blood flow to the heart. EECP may stimulate the openings or formation of collateral vessels to create a "natural bypass" around narrowed or blocked arteries.

A small recorder (monitor) is attached to electrodes on your chest. It is worn continuously for a period of time. If symptoms are felt, an event button can be depressed, and the heart's rhythm is recorded and saved in the recorder. The rhythm can be saved and transmitted over the phone line.

A procedure that combines echocardiography with exercise to evaluate the heart's function at rest and with exercise. It can evaluate the heart muscle to determine if it is receiving enough oxygen, as well as evaluate the function of the valves. Echocardiography is an imaging procedure that creates a picture of the heart's movement, valves, and chambers using high-frequency sound waves that come from a hand held wand placed on your chest. Echo is often combined with Doppler ultrasound and colour Doppler to evaluate blood flow across the heart's valves.

A test used to provide information about how the heart responds to stress. It usually involves walking on a treadmill or pedaling a stationary bike at increasing levels of difficulty, while the electrocardiogram, heart rate, and blood pressure are monitored. If you are not able to do activity, medications may be used to "stress" the heart.

Abnormally rapid, inefficient contractions of the atria or ventricles. Ventricular fibrillation is life-threatening.

One form of rapid heartbeat.

When the surgeon removes the mammary artery from its origin to use as a heart bypass graft.

A destructive fragment of oxygen produced as a by-product. Increased free radicals are thought to trigger atherosclerosis.

A test used to determine the cause of fainting spells. The test involves being tilted at different angles for a period of time. Heart rhythm, blood pressure, and other measurements are evaluated with changes in position.

A lack of blood supply to the heart that is usually caused by a blood clot in the coronary artery. This results in permanent damage to the heart muscle and the severity of damage varies from normal, mild, to severe.

Symptoms of a heart attack include:

• Discomfort, pressure, heaviness, tightness, squeezing, or pain in your chest or arm or below your breastbone

• Discomfort that goes into your back, jaw, throat, or arm

• Fullness, indigestion, or a choking feeling (it may feel like heartburn)

• Sweating, upset stomach, vomiting, or dizziness

• Severe weakness, anxiety, fatigue, or shortness of breath

• Fast or uneven heartbeat

Symptoms can be different from person to person or from one heart attack to another. Women are more likely to have these heart attack symptoms:

• Unusual fatigue

• Shortness of breath

• Nausea or vomiting

• Dizziness or light-headedness

• Discomfort in your gut. It may feel like indigestion.

• Discomfort in the neck, shoulder, or upper back

With some heart attacks, you won’t notice any symptoms (a "silent" myocardial infarction). This is more common in people who have diabetes.

Also called an arrhythmia, the electrical current is slowed between the atria and ventricles. In more severe cases, conduction is blocked completely, and the atria and ventricles beat independently. This is when a pacemaker would be suggested.

The most common symptom of coronary artery disease is angina, or chest pain. Angina can be described as a discomfort, heaviness, pressure, aching, burning, fullness, squeezing, or painful feeling in your chest. It can be mistaken for indigestion or heartburn. Angina may also be felt in the shoulders, arms, neck, throat, jaw, or back.

Other symptoms of coronary artery disease include:

• Shortness of breath

• Palpitations (irregular heart beats, or a "flip-flop" feeling in your chest)

• A faster heartbeat

• Weakness or dizziness

• Nausea

• Sweating

A progressive condition where the heart muscle weakens and cannot pump blood efficiently. Fluid accumulates in the lungs, ankles, or other parts of the body and is often associated with shortness of breath.

A machine that oxygenates the blood and circulates it throughout the body during surgery.

Heart surgery is any surgery that involves the heart or heart valves.

There are four valves in the heart: the tricuspid and the mitral valve, which lie between the atria and ventricles, and the pulmonic and aortic valves, which lie between the ventricles and the blood vessels leaving the heart. The heart valves help to maintain one-way blood flow through the heart.

After a heart attack, some areas of heart muscle do not pump as they should. Some areas will have permanent damage. Other areas are able to return to their normal function if blood flow is returned to that area by medications or a procedure. Hibernating myocardium is heart muscle that is ''stunned or in shock" and may possibly return to normal function.

A small recorder (monitor) is attached to electrodes on your chest. It records the heart's rhythm continuously for 24-hours as you go about your normal activities. After the monitor is removed the heart's beats are counted and analysed by a technician with the aid of a computer. Your doctor can learn if you are having irregular heartbeats, what kind they are, how long they last, as well as what may cause them.

An amino acid in the body. High levels of homocysteine are a risk factor for coronary artery disease. It is a common amino acid in your blood. You get it mostly from eating meat.

High blood pressure.

See IHSS below.

An abnormal enlargement of an organ or thickening of its tissue. Ventricular hypertrophy is the name given to a thickened ventricle.

Low blood pressure.

A congenital condition (present at birth). This is rare heart defect where the left side of the heart is extremely underdeveloped therefore the left side of the heart can't pump blood well. As a result the right side of the heart must pump blood to the lungs and to the rest of the body.

When the cause of a disease or process is not known.

Idiopathic Hypertrophic Subaortic Stenosis is another term used synonymously with hypertrophic obstructive cardiomyopathy (HOCM). It is an inherited disease that causes thickening of the heart muscle and other changes to the heart that significantly impair its function. Although the disease is rare, IHSS is the single most common cause of sudden cardiac arrest which is when a person collapses without warning. Your heart stops beating, and blood stops flowing to your brain and other organs. Within seconds, you stop breathing and have no pulse.

Drugs that are used to keep the body's immune system from rejecting a transplanted organ, such as the heart, or to slow down the destructive processes of autoimmune disease (where the body's immune system goes awry and kills normal cells and tissue).

A surgically inserted electronic device that constantly monitors your heart rate and rhythm. When it detects a very fast, abnormal heart rhythm, it delivers electrical energy to the heart muscle to help the heart to beat in a normal rhythm again.

Tissue death due to lack of oxygen-rich blood.

A medication used to strengthen the heart's contractions and improve blood circulation.

A machine that can help the pumping function of the heart. It is usually inserted through an artery in the groin area and threaded backwards into the descending thoracic aorta in the chest. In this location, the balloon inflates and deflates in synchrony with the heart in order to aid the blood pumping function of the heart in people whose heart has been damaged, most often due to a heart attack.

An intracardiac tumour can be any tumour of the heart, either malignant or benign. The most common tumour of the heart is a benign atrial myxoma.

Inside a blood vessel.

An invasive procedure, performed along with cardiac catheterisation. A miniature sound probe (transducer) on the tip of a catheter is threaded through the coronary arteries and, using high-frequency sound waves, produces detailed images of the interior walls of the arteries.

Condition in which there is not enough oxygen-rich blood supplied to the heart muscle to meet the heart's needs.

A congenital condition (present at birth). Swelling (inflammation) in children in the walls of small to medium-sized blood vessels that carry blood throughout the body. This disease commonly leads to inflammation of the coronary arteries, which supply oxygen-rich blood to the heart. Previously called mucocutaneous lymph node syndrome because it also causes swelling in glands (lymph nodes) and mucous membranes inside the mouth, nose, eyes and throat.

A battery-operated, mechanical pump used for patients who have reached end-stage heart failure. The LVAD is surgically implanted and helps the left ventricle (main pumping chamber of the heart) pump blood to the rest of the body.

A lead is a special wire that delivers energy from a pacemaker or implantable cardioverter defibrillator (ICD) to the heart muscle. A lead extraction is the removal of one or more leads from inside the heart.

Thin pieces of tissue or flaps that make up a valve.

A combination of fat and protein that transports lipids (fats) in the blood.

A congenital condition (present at birth). A heart signalling disorder that can cause fast, chaotic heartbeats (arrhythmias). Also called a heart conduction disorder. Some people are born with altered DNA that causes long QT syndrome (congenital long QT syndrome). This syndrome may also occur later in life (acquired long QT syndrome) as the result of some medical conditions, certain drugs or mineral imbalances.

See Event monitor (above).

A lipoprotein particle in the blood responsible for depositing cholesterol into the lining of the artery. Known as "bad" cholesterol, because high LDL is linked to coronary artery disease.

A test that produces high-quality still and moving pictures of the heart and large blood vessels. MRI uses large magnets and radio-frequency waves to produce pictures of the body's internal structures. No x-ray exposure is involved. MRI acquires information about the heart muscle as it is beating, creating moving images of the heart throughout its pumping cycle.

Artery located in the chest wall and used for coronary artery bypass surgery. Most commonly kept intact at its origin, and sewn to the coronary artery beyond the site of blockage. If the surgeon removes the mammary artery from its origin to use as a bypass graft, it is then called a "free" mammary artery bypass graft.

A surgical treatment for chronic atrial fibrillation. The surgeon makes multiple incisions in the atrium to form a path or maze through which the impulse can travel to reach the atrioventricular node. After this is done, the atrium is sewn back together and a normal rhythm is more easily maintained.

In people who require heart valve replacement surgery, it is sometimes desirable to implant a mechanical valve. A mechanical valve is made of artificial parts and functions similarly to a normal heart valve. People who have a mechanical valve implanted must take blood thinners lifelong to prevent blood clots from forming on the mechanical valve.

A test used to measure the performance of the heart and lungs while they are under physical stress. The test involves walking on a treadmill or pedaling a stationary bike at increasing levels of difficulty, while being closely monitored.

Minimally invasive heart surgery is a technique developed to reduce the trauma associated with open heart surgery. The smaller incision that is used may allow the patient to heal more rapidly. It also helps to reduce the pain and discomfort associated with heart surgery.

A condition where blood in the left ventricle leaks back through the mitral valve into the left atrium and can back up into the lungs. The mitral valve normally opens to allow blood to flow into the left ventricle and then closes, preventing blood from backing up into the atrium during the ventricle's contraction. This may be associated with mitral valve prolapse or can develop due to other forms of heart disease.

A condition where the mitral valve becomes narrowed (stenotic), preventing the easy flow of blood from the left atrium into the left ventricle.

The valve that lies between the left atrium and left ventricle (main pumping chamber of the heart). This valve allows blood to flow from the left atrium into the left ventricle and then prevents the back flow of blood into the left atrium during ventricular contraction.

The percentage of people who have complications from a medical condition or after a procedure or treatment.

The percentage of deaths associated with a disease or medical treatment.

A nuclear scan that evaluates the pumping function of the ventricles by determining the heart's ejection fraction.

Turbulent blood flow across a heart valve that creates a "swishing" sound heard by a stethoscope. This sound can be due to a valve being too tight, leaky or occur from a congenital abnormality to the heart, such as a hole or stricture.

An invasive procedure to obtain a small piece of heart muscle tissue that is sent to a laboratory for analysis.

See heart attack (above).

Inflammation of the myocardium (heart muscle). May feel like a heart attack and appear to be one, until further testing is done.

Heart muscle.

A surgical procedure to remove abnormally thickened heart muscle. Myomectomy is used to treat people with idiopathic hypertrophic subaortic stenosis (IHSS) or HOCM, thereby relieving the obstruction to blood flow in the left ventricle during contraction.

A heart attack that does not cause changes known as "Q-waves" on the electrocardiogram (ECG). However, other changes on the ECG are often seen. In addition, chemical markers in the blood indicate that damage has occurred to the heart muscle. In non-Q-wave MI, a clot may block the coronary artery for a period of time, and then break up by itself or collateral circulation may help to restore blood flow. The size of damage is fairly small; therefore, overall function of the heart is usually maintained, unless there have been multiple events. This is the most common type of heart attack in women.

Blockage.

Heart surgery done without the use of the cardiopulmonary bypass machine.

A small electronic device implanted under the skin that sends electrical impulses to the heart muscle to maintain a suitable heart rate and to prevent slow heart rates. Depending on the patient’s condition, they may have one of the following types of pacemakers.

• Single chamber pacemaker. This type usually carries electrical impulses to the right ventricle of the heart.

• Dual chamber pacemaker. This type carries electrical impulses to the right ventricle and the right atrium of the heart to help control the timing of contractions between the two chambers.

• Biventricular pacemaker. Biventricular pacing, also called cardiac resynchronisation therapy, is for people who have heart failure and heartbeat problems. This type of pacemaker stimulates both of the lower heart chambers (the right and left ventricles) to make the heart beat more efficiently.

A fluttering sensation in the chest that is often related to a missed heart beat or rapid heartbeat.

Palpitations make you feel like your heart is beating too hard or too fast, skipping a beat, or fluttering. You may notice heart palpitations in your chest, throat, or neck.

They can be bothersome or frightening. They usually aren't serious or harmful, though, and often go away on their own. Most of the time, they're caused by stress and anxiety, or because you’ve had too much caffeine, nicotine, or alcohol. They can also happen when you’re pregnant.

In rare cases, palpitations can be a sign of a more serious heart condition. If you have heart palpitations, see your doctor.

Small muscles that are part of the inside walls of the ventricles and attach to the chordae tendineae.

A congenital condition (present at birth). A rare heart defect that may also be called partial anomalous pulmonary venous connection (PAPVC). Some but not all of the lung blood vessels (pulmonary veins) are attached to the wrong place in the heart. An abnormal connection of veins sends blood into other blood vessels and into the upper right heart chamber (right atrium), where it mixes with oxygen-poor blood. As a result, extra oxygen-rich blood flows back to the lungs. Some people with this heart defect also have a hole between the upper heart chambers (atrial septal defect), which allows blood to flow between the upper heart chambers (atria). Other congenital heart defects also may occur. A child born with Turner syndrome has an increased risk of PAPVR.

The likelihood that a vessel will remain open.

A congenital condition (present at birth). A persistent opening between the two major blood vessels leading from the heart. The opening (ductus arteriosus) is a normal part of a baby's circulatory system in the womb that usually closes shortly after birth. If it remains open, it's called a patent ductus arteriosus.

An invasive procedure that involves using a needle and catheter to remove fluid from the sac around the heart. The fluid may then be sent to a laboratory for tests to look for signs of infection, autoimmune disease, or cancer.

The sac that surrounds the heart.

Pericarditis is an inflammation of the pericardium, the sac around the heart.

Deposits of fats, inflammatory cells, proteins, and calcium material along the lining of arteries seen in atherosclerosis. The plaque builds up and narrows the artery.

An imaging procedure that uses radioactive tracers to create 3-dimensional pictures of the tissues inside of the body and can monitor metabolic processes.

An irregular heartbeat in which the lower chambers of the heart (the ventricles) beat before they are supposed to.

The prevention of disease.

A congenital condition (present at birth). A heart defect usually diagnosed soon after birth because babies with pulmonary atresia typically have a bluish cast to their skin due to lack of enough oxygen. The valve that lets blood out of the heart to go to the lungs (pulmonary valve) doesn't form correctly. Instead of opening and closing to allow blood to travel from the heart to the lungs, a solid sheet of tissue forms. So, blood can't travel its usual route to pick up oxygen from the lungs. Instead, some blood travels to the lungs through other natural passages within the heart and its arteries.

An abnormal swelling of tissue in the lungs due to fluid build-up.

High blood pressure of the pulmonary arteries.

A congenital condition (present at birth). A narrowing of the valve located between the lower right heart chamber (right ventricle) and the lung arteries (pulmonary arteries). In a narrowed heart valve, the valve flaps (cusps) may become thick or stiff. This reduces blood flow through the valve. Adults may develop pulmonary valve stenosis as a complication of another illness.

The last valve through which the blood passes before it enters the pulmonary artery that lies between the right atrium and goes from the right ventricle to the lungs.

The number of heart beats per minute. The resting pulse rate for an average adult is between 50 and 90 beats per minute.

A heart attack that is caused by a prolonged period of blocked blood supply. An area of the heart muscle is affected, causing changes known as "Q-waves" on the ECG and chemical markers in the blood, usually implying that the full thickness of the heart muscle was affected in the heart attack, causing that part of the muscle to die.

The radial artery is a blood vessel that carries oxygen-rich blood in the forearm. You can feel the pulse of the radial artery by feeling the inside of the wrist underneath the base of the thumb.

See MUGA above.

Leaking or backward flow.

The closing or narrowing of an artery that was previously opened by a procedure such as angioplasty or a stent.

Rheumatic fever is an inflammatory reaction (usually in response to a strep infection) that can involve the heart and heart valves.

Rheumatic fever can lead to a condition known as rheumatic heart disease. This is usually a thickening and stenosis of one or more of the heart valves and often requires surgery to repair or replace the involved valve(s).

Rheumatic valve disease is a consequence of rheumatic fever. It is a thickening and stenosis of one or more of the heart valves and often requires surgery to repair or replace the affected valve(s).

The removal of a small piece of heart tissue from your right ventricle. This tissue sample is studied under a microscope to help your doctor assess your heart muscle.

Traits people have that are linked to the development and progression of coronary artery disease. There are modifiable risk factors (related to lifestyle and may be changed or controlled) and non-modifiable risk factors (related to aging and genetics) and cannot be changed.

A special catheter, with an acorn-shaped diamond-coated tip, is guided to the point of narrowing in the coronary artery. The tip spins around at a high speed and grinds away the plaque on the artery walls. The microscopic particles are washed safely away in your blood stream and filtered out by the liver and spleen. This process is repeated as needed to allow better blood flow.

Vein located in the leg(s) and used for coronary artery bypass surgery. It is surgically removed from the leg and sewn from the aorta to the coronary artery beyond the site of blockage.

The muscular wall separating the right and left sides of the heart.

A diagnostic study, which uses a small amount of radioactive tracer, injected into the body, and a special camera, which detects the radiation, to produce a computer image of the heart. Combined with exercise, the study can help determine if there is adequate blood flow to the heart at rest, as compared with activity.

Inadequate supply of oxygen-rich blood to the heart that does not cause symptoms such as chest pain, or is ignored or dismissed without being diagnosed as atherosclerosis or a decrease in oxygen delivery to the heart muscle.

A specialized cluster of cells in the heart that initiates the heartbeat. Known as the heart's natural pacemaker.

A mineral found in most of the foods we eat. The largest source of dietary sodium comes from sodium chloride or table salt. Intake of sodium tends to increase the retention of water and blood pressure.

A device for measuring blood pressure.

Narrowing or restriction of a blood vessel or valve that reduces blood flow.

A small tube, inserted after angioplasty, that acts as a scaffold to provide support inside the coronary artery. The goal is to keep the artery open. The current acceptable origin of the word stent is that it derives from the name of a dentist. Charles Thomas Stent (1807 to 1885) was an English dentist notable for his advances in the field of denture-making.

Bone in chest separated during open heart surgery.

See Exercise Stress Test.

A sudden loss of brain function due to decreased blood flow to an area of the brain.

If blood flow is returned to an area of heart muscle after a period of ischemia (lack of blood supply), the heart muscle may not pump normally for a period of days following the event. This is called "stunned" heart muscle or myocardium.

A narrowing of the flow of blood below the aortic valve in the left ventricle. It is usually caused by a membrane or thickening in the muscle in this area.

Fainting.

The portion of the cardiac cycle in which the heart muscle contracts, forcing the blood into the main blood vessels.

The pressure of the blood in the arteries when the heart pumps. It is the higher of two blood pressure measurements (for example, 120/80, where 120 is the systolic pressure).

Rapid heartbeat. A condition that makes your heart beat more than 100 times per minute. There are three types of it:

• Supraventricular. This happens when the electrical signals in the organ's upper chambers misfire and cause the heart rate to speed up. It beats so fast that it can’t fill with blood before it contracts. That reduces blood flow to the rest of your body.

• Ventricular. This is a rapid heart rate that starts in your heart's lower chambers. It happens when the electrical signals in these chambers fire the wrong way. Again, the heart beats so fast that it can’t fill with blood or pump it through the rest of your body.

• Sinus tachycardia. This happens when your heart’s natural pacemaker sends out electrical signals faster than normal. Your ticker beats fast, but it beats the way it should.

A congenital condition (present at birth). A rare condition caused by a combination of four heart defects. These defects, which affect the structure of the heart, cause oxygen-poor blood to flow out of the heart and to the rest of the body. Infants and children with tetralogy of Fallot usually have blue-tinged skin because their blood doesn't carry enough oxygen.

A type of nuclear scanning technique that uses the radioactive substance thallium. A thallium stress test combines nuclear scanning with exercise on a treadmill or stationary bicycle to assess heart function and determine if there is adequate blood flow to the myocardium.

Medication used to dissolve any clots that may be blocking blood flow in arteries and veins.

A blood clot.

The total amount of cholesterol in the blood.

A congenital condition (present at birth). A rare heart sometimes called total anomalous pulmonary venous connection (TAPVC). In this heart defect, the lung blood vessels (pulmonary veins) are attached to the wrong place in the heart. Normally, oxygen-rich blood goes from the lungs to the upper left heart chamber (left atrium) and then flows through the body. In TAPVR, an abnormal connection of veins sends blood through the upper right heart chamber (right atrium) instead, where it mixes with oxygen-poor blood. As a result, blood flowing to the body doesn't have enough oxygen.

A congenital condition (present at birth). A serious, rare heart problem in which the two main arteries leaving the heart are reversed (transposed). There are two types of TGA:

• Complete transposition of the great arteries, also called dextro-transposition of the great arteries (D-TGA), causes a shortage of oxygen-rich blood to the body. Symptoms are usually noticed during pregnancy, immediately after birth or within a few weeks of birth. Without treatment, serious complications or death can occur.

• Congenitally corrected transposition, also called levo-transposition of the great arteries (L-TGA), is a less common type of this condition. Symptoms may not be noticed right away. Treatment depends on the specific heart defects.

An invasive imaging procedure that creates a picture of the heart's movement, valves, and chambers using high frequency sound waves that come from a small transducer passed down your throat. TEE provides clear images of the heart's movement because the transducer is close to the heart and limits interference from air in the lungs. Echo is often combined with Doppler ultrasound and colour Doppler to evaluate blood flow across the heart's valves.

A stroke-like event lasting minutes, or hours, that occurs when the brain is deprived of oxygen-rich blood, but in which the effects wear off completely after resumption of blood flow.

A procedure used in people with severe heart disease who are not candidates for bypass surgery. In this procedure, an incision is made in the chest. The heart is exposed and small holes are drilled through the wall of the heart with a laser. The benefits of TMR have not been proven.

A small monitor is attached to electrode leads (usually on your finger or wrist). Your heart's rhythm is transmitted over the phone line with the aid of this device to your doctor's office.

A congenital condition (present at birth). A heart defect where a valve (tricuspid valve) between two of the heart's chambers isn't formed. Instead, there's solid tissue between the chambers, which restricts blood flow and causes the right lower heart chamber (ventricle) to be underdeveloped. A baby, child or adult with tricuspid atresia can't get enough oxygen through its body. People with this condition tire easily, are often short of breath and have blue-tinged skin.

A congenital condition (present at birth). A rare heart defect where one large blood vessel leads out of the heart. Normally, there are two separate vessels coming out of the heart. In addition, there is usually a hole — known as a ventricular septal defect — between the two lower chambers of the heart. As a result of truncus arteriosus, oxygen-poor blood that should go to the lungs and oxygen-rich blood that should go to the rest of the body are mixed. This creates severe circulatory problems.

The tricuspid valve is the valve that separates the right atrium from the right ventricle and prevents blood from flowing back into the right atrium during contraction of the ventricle.

A fat found in the blood. Most fat found in the diet and body is in the form of triglycerides. It is often associated with a high-carbohydrate diet and if elevated, is a risk factor for heart disease. Many times people with diabetes have elevated triglycerides.

This type of chest pain is considered an acute coronary syndrome. It may be a new symptom or a change from stable angina. It may come more often, occur at rest, or feel more severe. Although this angina can be relieved with oral medications, it is unstable and may progress to a heart attack. Usually medical treatment or a procedure is required to prevent a heart attack from developing.

Structures that maintain the proper direction of blood flow in the heart. There are four valves in the heart: the tricuspid and the mitral valve, which lie between the atria and ventricles, and the pulmonic and aortic valves, which lie between the ventricles and the blood vessels leaving the heart.

A procedure to improve valve function. A balloon is used to at the time of cardiac catheterization to increase the area of a narrowed valve.

A type of angina (chest pain) that occurs at rest; most often due to coronary spasm.

Any condition that affects the network of your blood vessels.

This network is known as your vascular or circulatory system. "Vascular" comes from a Latin word for hollow container. If your entire network of blood vessels were stretched end-to-end, they could circle the Earth multiple times.

Some of these vessels move blood. As your heart beats, it pumps blood with oxygen and nutrients to feed your tissues and carry off waste. Arteries move blood away from the heart. Veins return it.

A congenital condition (present at birth). These are malformations of the aortic arch in the main blood vessel that leads from the heart. Because of the malformation, the aortic arch and its branches partly or completely encircle the windpipe (trachea), the esophagus or both. The esophagus is the tube that leads from your mouth to your stomach.

A type of medication that relaxes and dilates the blood vessels, allowing increased blood flow.

Blood vessels that carry blood toward the heart. This blood is usually deoxygenated and goes back to the heart first before getting oxygen from the lungs.

The lower, pumping chambers of the heart. The heart has two ventricles - the right and left ventricle.

An erratic, disorganized firing of impulses from the ventricles. The ventricles quiver and are unable to contract or pump blood to the body. This is a medical emergency that must be treated with cardiopulmonary resuscitation (CPR) and defibrillation as soon as possible.

In people who suffer a significant heart attack, it is sometimes the case that the area of the muscle wall of the heart that is affected can become so weakened that it ruptures and leaks blood from the inner chamber of the heart.

A congenital condition (present at birth). Also called a hole in the heart is a common heart defect. The hole (defect) occurs in the wall (septum) that separates the heart's lower chambers (ventricles) and allows blood to pass from the left to the right side of the heart. The oxygen-rich blood then gets pumped back to the lungs instead of out to the body, causing the heart to work harder.

A rapid life-threatening rhythm originating from the lower chambers of the heart. The rapid rate prevents the heart from filling adequately with blood, and less blood is able to pump through the body.

A congenital condition (present at birth)WPW is a form of supraventricular tachycardia (fast heart rate originating above the ventricles). People with WPW have more than one electrical conduction pathway in their hearts (accessory pathways.) These electrical impulses set up a short circuit, causing the heart to beat rapidly and conduct impulses in both directions. The impulses travel through the extra pathway (short cut) as well as the normal AV-His-Purkinje system. The impulses can travel around the heart very quickly, in a circular pattern, causing the heart to beat unusually fast. This type of arrhythmia is called re-entry tachycardia.