heart guide
The Normal Heart
Signs and Symptoms
Heart Diseases and Disorders
Substances Causing Arrhythmias
Do you know your EF?
Risk Factors and Prevention
Heart Tests
Have you had a Heart Attack?
Know Your Heart
Warning Signs
Heart Attack

The center provides accurate, clear and understandable information about cardiac arrhythmia disorders. Designed to educate public and the patients , the site aims to further understanding of heart rhythm problems

Each of the following sections begins with an overview of the topic. The next level of information has more detail for those with specific interests.

  Heart Anatomy

The heart weighs between 7 and 15 ounces (200 to 425 grams) and is a little larger than the size of your fist. By the end of a long life, a person's heart may have beat (expanded and contracted) more than 3.5 billion times. In fact, each day, the average heart beats 100,000 times, pumping about 2,000 gallons (7,571 liters) of blood.

Your heart is located between your lungs in the middle of your chest, behind and slightly to the left of your breastbone (sternum). A double-layered membrane called the pericardium surrounds your heart like a sac. The outer layer of the pericardium surrounds the roots of your heart's major blood vessels and is attached by ligaments to your spinal column, diaphragm, and other parts of your body. The inner layer of the pericardium is attached to the heart muscle. A coating of fluid separates the two layers of membrane, letting the heart move as it beats, yet still be attached to your body.

Your heart has 4 chambers. The upper chambers are called the left and right atria, and the lower chambers are called the left and right ventricles. A wall of muscle called the septum separates the left and right atria and the left and right ventricles. The left ventricle is the largest and strongest chamber in your heart. The left ventricle's chamber walls are only about a half-inch thick, but they have enough force to push blood through the aortic valve and into your body.

The Heart Valves

Four types of valves regulate blood flow through your heart:

The tricuspid valve regulates blood flow between the right atrium and right ventricle.

The pulmonary valve controls blood flow from the right ventricle into the pulmonary arteries, which carry blood to your lungs to pick up oxygen.

The mitral valve lets oxygen-rich blood from your lungs pass from the left atrium into the left ventricle.

The aortic valve opens the way for oxygen-rich blood to pass from the left ventricle into the aorta, your body's largest artery, where it is delivered to the rest of your body.

The Heartbeat

heartbeat is a two-part pumping action that takes about a second. As blood collects in the upper chambers (the right and left atria), the heart's natural pacemaker (the SA node) sends out an electrical signal that causes the atria to contract. This contraction pushes blood through the tricuspid and mitral valves into the resting lower chambers (the right and left ventricles). This part of the two-part pumping phase (the longer of the two) is called the diastole.

The second part of the pumping phase begins when the ventricles are full of blood. The electrical signals from the SA node travel along a pathway of cells to the ventricles, causing them to contract. This is called systole. As the tricuspid and mitral valves shut tight to prevent a back flow of blood, the pulmonary and aortic valves are pushed open. While blood is pushed from the right ventricle into the lungs to pick up oxygen, oxygen-rich blood flows from the left ventricle to the heart and other parts of the body.

After blood moves into the pulmonary artery and the aorta, the ventricles relax, and the pulmonary and aortic valves close. The lower pressure in the ventricles causes the tricuspid and mitral valves to open, and the cycle begins again. This series of contractions is repeated over and over again, increasing during times of exertion and decreasing while you are at rest. The heart normally beats about 60 to 80 times a minute when you are at rest, but this can vary. As you get older, your resting heart rate rises. Also, it is usually lower in people who are physically fit.

Your heart does not work alone, though. Your brain tracks the conditions around you—climate, stress, and your level of physical activity—and adjusts your cardiovascular system to meet those needs.

The human heart is a muscle designed to remain strong and reliable for a hundred years or longer. By reducing your risk factors for cardiovascular disease, you may help your heart stay healthy longer.

The Conduction System

Electrical impulses from your heart muscle (the myocardium) cause your heart to contract. This electrical signal begins in the sinoatrial (SA) node, located at the top of the right atrium. The SA node is sometimes called the heart's "natural pacemaker." An electrical impulse from this natural pacemaker travels through the muscle fibers of the atria and ventricles, causing them to contract. Although the SA node sends electrical impulses at a certain rate, your heart rate may still change depending on physical demands, stress, or hormonal factors.

The Circulatory System

Your heart and circulatory system make up your cardiovascular system. Your heart works as a pump that pushes blood to the organs, tissues, and cells of your body. Blood delivers oxygen and nutrients to every cell and removes the carbon dioxide and waste products made by those cells. Blood is carried from your heart to the rest of your body through a complex network of arteries, arterioles, and capillaries. Blood is returned to your heart through venules and veins. If all the vessels of this network in your body were laid end-to-end, they would extend for about 60,000 miles (more than 96,500 kilometers), which is far enough to circle the earth more than twice!

The one-way circulatory system carries blood to all parts of your body. This process of blood flow within your body is called circulation. Arteries carry oxygen-rich blood away from your heart, and veins carry oxygen-poor blood back to your heart.

In pulmonary circulation, though, the roles are switched. It is the pulmonary artery that brings oxygen-poor blood into your lungs and the pulmonary vein that brings oxygen-rich blood back to your heart.

In the diagram, the vessels that carry oxygen-rich blood are colored red, and the vessels that carry oxygen-poor blood are colored blue.

Twenty major arteries make a path through your tissues, where they branch into smaller vessels called arterioles. Arterioles further branch into capillaries, the true deliverers of oxygen and nutrients to your cells. Most capillaries are thinner than a hair. In fact, many are so tiny, only one blood cell can move through them at a time. Once the capillaries deliver oxygen and nutrients and pick up carbon dioxide and other waste, they move the blood back through wider vessels called venules. Venules eventually join to form veins, which deliver the blood back to your heart to pick up oxygen.

Have you had a Heart Attack?

Do you know your EF?


Signs and Symptoms

Some arrhythmias don’t cause any symptoms. Others announce themselves quite clearly, perhaps with the distinct feeling that the heart is racing. Still other arrhythmias cause symptoms that aren’t obviously heart-related, such as lightheadedness or dizziness. Most adults will, at some point, experience fleeting, and harmless heart rhythm changes. Certain arrhythmias, especially those that last long enough to impact heart function, can be serious or even fatal.

Palpitation or a Skipped Beat
Although it may seem as if the heart missed a beat, really the heart has a premature heartbeat, almost an extra beat happening too soon, which may result in a pause – the "skipped beat." [more]

A fluttering sensation is usually due to a series of "skipped beats" that occur in quick succession. [more]

Slow Heartbeat – Bradycardias [more]
If the heartbeat is too slow, usually considered a rate below 60 beats a minute, not enough oxygen-rich blood flows through the body. So, it makes sense that the symptoms of a slow heartbeat are:

  • Fatigue
  • Dizziness
  • Lightheadedness
  • Fainting or near fainting

Rapid Heartbeat – Tachycardias [more]
When the heart beats too quickly, usually considered a rate above 100 beats a minute, the lower chambers, or ventricles, do not have enough time to fill with blood, so they cannot effectively pump blood to the rest of the body. When this happens, some people experience:

  • Skipping a beat
  • Beating out of rhythm
  • Palpitations
  • Rapid heart action
  • Shortness of breath
  • Chest pain
  • Dizziness
  • Lightheadedness
  • Fainting or near fainting
  • Chaotic, quivering or irregular rhythm

Suddenly rapid, irregular and chaotic heartbeats may be a sign of the most dangerous arrhythmia, ventricular fibrillation. It is the number one cause of sudden cardiac death. Within seconds, an individual loses consciousness and, without immediate emergency treatment, will die within minutes.

Almost Fainting – Presyncope
Sometimes people experience symptoms before they faint. Presyncope can be a sign of a heart rhythm disorder and should be evaluated carefully.

  • Dizziness, lightheadedness or vertigo
  • Blurred or narrowed (tunnel) vision
  • Sweating
  • Nausea and/or vomiting
  • Stomachache/abdominal discomfort
  • Heart palpitations
  • Headache
  • Confusion and/or difficulty
  • speaking clearly or coherently

Fainting - Syncope [more]
Fainting related to a heart rhythm disorder is more likely to happen suddenly and without warning than fainting related to other causes, such as dehydration or low blood sugar. Any sudden lose of consciousness should be evaluated by a physician.
In some cases, fainting is the only warning sign of an arrhythmia that could cause sudden cardiac death.

Heart Attack

A heart attack (myocardial infarction) occurs when heart muscle is damaged or destroyed because it does not get enough oxygen-rich blood to sustain life. Just as the heart supplies oxygen and nutrients to other parts of the body, blood vessels called coronary arteries supply needed blood to the heart. If one or more coronary arteries or the blood vessels that feed blood into the major arteries are blocked or narrowed, the heart muscle is deprived of oxygen. If the oxygen supply is cut off for more than several minutes, the heart cells suffer permanent injury or death.

The medical term for heart attack is myocardial (meaning "heart muscle") infarction (an area of dead heart tissue is an "infarct").

The heart has four major arteries. Blood is pumped out through the largest of these arteries, the aorta, which circulates it through the body. The pulmonary artery supplies blood to the lungs. The right and left coronary arteries bring oxygen rich blood to the heart itself.

Myocardial Infarction is not the same as cardiac arrest, or sudden cardiac death (SCD)!

SCD is caused by a deadly heart rhythm disorder (arrhythmia) called ventricular fibrillation (VF).

Heart attack survivors often are at risk for sudden cardiac arrest. This is because a heart attack can damage areas of heart muscle that affect the electrical conduction system of the heart. This system is responsible for sending the signals that tell the heart when to contract, and regulate the heart's steady rhythmic beat.

In VF, the electrical signals that trigger the heartbeat become very fast and chaotic in the lower chambers of the heart. The heart no longer can pump blood to the brain or body. Without immediate emergency help, the heart cannot recover. Heart disease is the leading cause of death in the U.S. About half of all deaths from heart disease are due to sudden cardiac arrest, the inevitable result of VF.

What Causes a Heart Attack?

Heart attacks most often result from coronary heart disease (also called coronary artery disease or ischemic heart disease). The most common cause is atherosclerosis ("hardening of the arteries"), a build-up of fatty deposits called plaque. Over time, plaque clogs and narrows the arteries and other blood vessels, and slows or blocks the flow of blood to the heart and elsewhere. Sometimes, the surface of plaques can rupture or tear, which can cause blood clots to form that block the arteries. A complete or near-complete blockage of the coronary arteries results in a heart attack.

Signs and Symptoms

The signs and symptoms of a heart attack vary from person to person, but they usually are not as obvious and dramatic as people imagine. Many heart attacks start slowly, usually with a feeling of pain or discomfort in the chest that lasts more than a few minutes, or goes away and returns. Pain from a heart attack generally lasts for more than 30 minutes, and may continue for several hours. The longer the pain lasts, the greater the risk of muscle damages. Chest pain due to a reduced blood supply to the heart is called angina. It may be a warning signal of a heart attack.

People may feel different symptoms during a heart attack or MI - and some people feel no unusual symptoms. Classic heart attack symptoms are described as:

An intense aching in the left side or center of the chest
Sometimes, the pain radiates into the neck, back, arms or jaw
A feeling of extreme pressure, fullness, or tightness in the chest
Nausea, dizziness, weakness, shortness of breath, or a cold sweat also can be experienced
Not everyone experiences acute chest pain and some may have a combination of symptoms. Other heart attack survivors report a vague feeling that their heart or health is "not quite right." There may be only a slight discomfort. About one-quarter of all heart attacks occur without producing any noticeable warning signs. These "silent" heart attacks may go undiscovered until they show up during routine heart tests such as an electrocardiogram (ECG).

If you think you may be having a heart attack, even if the symptoms are mild, seek medical attention immediately.

When in doubt, it is best to call your doctor, go to the nearest emergency room, or call as soon as your symptoms develop.

The sooner emergency treatment is provided, the greater the chance that permanent damage to the heart muscle can be avoided.

When administered shortly after the onset of a heart attack, clot-busting drugs (called thrombolytic therapy), angioplasty or other treatments may be able to open blocked coronary arteries and restore the normal supply of blood and oxygen to the heart. The more time that goes by, the more harm is done to the heart muscle.

What's your Ejection Fraction (EF)?

The proportion, or fraction, of blood pumped out of your heart with each beat is called the ejection fraction, or EF. A normal heart pumps out a little more than half the heart's volume of blood with each beat. A normal EF is 55 percent or higher. Your doctor can order simple, painless tests such as an echocardiogram which creates a moving picture of your heart using harmless soundwaves, or a nuclear medicine test that show's how well your heart is pumping. If your EF is abnormally low, you may need further tests to see if you have an abnormal heart rhythm.

Many people who have survived a heart attack can benefit from an implantable cardiac defibrillator (ICD), a pacemaker-like device that treats ventricular fibrillation (VF), the deadly heart rhythm that causes sudden cardiac death. Recently, several large clinical studies were conducted to see if ICDs could prevent sudden cardiac death in people whose heart muscle - and its pumping ability -is damaged by a heart attack. In the studies, survival rates were significantly greater for people with ICDs than for people who received traditional medical care.

An ICD is a pacemaker-like device implanted under the skin. Wires called "leads" are placed in the heart to monitor the heart rate. When the device detects a potentially deadly heart rhythm disorder (arrhythmia), the ICD delivers a controlled, electric shock to restore the heart's normal rhythm. This device was implanted in vice-president Dick Cheney to monitor his heart rhythm and provide immediate treatment if his heart rate gets too slow or too fast.

Do you know your EF? If you don't, ask your doctor. It could save your life.
If you have had a heart attack, take our quiz to learn if you may be at high risk for sudden cardiac arrest.

Heart Disease and Disorders

Arrhythmias that originate in the heart’s upper
chambers, the atria

Atrial Fibrillation (AF or A Fib)
More than 2 million people in the United States have atrial fibrillation, making it a very common heart rhythm disorder. In A Fib, the heartbeat is irregular and rapid, sometimes beating as often as 300 times a minute, about four times faster than normal. Although it isn't life threatening, A Fib can lead to other rhythm problems, chronic fatigue and congestive heart failure. Chances of having a stroke are five times higher for those with A Fib. [more]

Atrial Flutter (AFL)
Atrial flutter is similar to A Fib because it too is characterized by a rapid heartbeat. Instead of many disorganized signals, however, AFL is caused by a single electrical wave that circulates very rapidly in the atrium, about 300 times a minute, leading to a very fast, steady heartbeat. [more]

Sick Sinus Syndrome (SSS)
SSS is not a specific disease, but a group of signs or symptoms that indicate the heart’s natural electrical pacemaker, the sinoatrial node, is not functioning properly. In SSS, the heart rate can switch back and forth between a slow rate (bradycardia) and a fast rate (tachycardia). A permanent pacemaker, sometimes in combination with medication, is the primary treatment. [more]

Sinus Tachycardia
A harmless rhythm, sinus tachycardia is a normal increase in heart rate that happens with fever, excitement and exercise. It does not require treatment except in rare cases when an underlying problem, such as anemia or hyperthyroidism, should be treated.

Arrhythmias that originate in the heart’s lower chambers, the ventricles
Ventricular Tachycardia (VT)

Characterized by a very fast heart rate,VT usually is seen in the setting of other serious heart disease. Occasionally, it occurs in people with normal hearts. It usually requires prompt treatment, sometimes with medication. Sometimes it is treated with radiofrequency ablation or surgery.Often people with VT are protected by implantation of a defibrillator. Because VT can lead to ventricular fibrillation (next item) it is considered a serious condition that warrants aggressive monitoring and treatment.

Ventricular Fibrillation (VF) Sudden cardiac death, caused by ventricular fibrillation, poses the greatest threat and accounts for half of all cardiac deaths. In VF, the heartbeat is rapid and chaotic,which causes the lower heart chambers, or ventricles, to go into a spasm. Sometimes, however, a heart attack can lead to VF. VF is abrupt and happens without any warning and it halts all heart functioning.The lack of oxygen throughout the body, and especially to the brain, is deadly.Also known as cardiac arrest, sudden cardiac death is due to an electrical circuitry problem. It is not a the same as a heart attack, or myocardial infarction,which is a circulatory problem caused by clogged blood vessels that cut off the supply of blood to the heart.

Although CPR can provide some benefit, the only truly effective VF treatment is defibrillation, which relies on paddles or electrodes to "shock" the heart back to normal rhythm. Without treatment, loss of consciousness comes in seconds, and death is inevitable. [more]

Premature Contractions
Extra, early or "skipped" beats are the most frequent cause of irregular heart rhythms.These can start in the upper or lower chambers of the heart

Long QT Syndrome (LQTS)
Long QT Syndrome is a disorder of the electrical system. It can be inherited, acquired after taking certain medications, or caused by a combination of heredity and medications. People with LQTS are susceptible to ventricular fibrillation. [more]

Heart Block
When electrical impulses generated in the upper chambers of the heart are not properly transmitted to the lower chambers,Heart Block happens.The heart then beats too slowly,reducing the oxygen that gets to the body and brain. [more]

Syncope (Fainting)
Fainting, or feeling as if one might faint, can be caused by serious heart rhythm disorders and needs to be evaluated carefully. Sometimes the cause is not heart related, for instance when low blood sugar is to blame, but still can be dangerous.No matter what the cause, fainting can be dangerous simply because of the potential for injuries from falling. [more]

Heart Attack (Myocardial Infarction) When arteries are clogged to the point of decreasing or stopping the flow of blood to the heart muscle, a lack of oxygen damages or kills heart muscle causing a heart attack. Recognizing symptoms and getting prompt emergency treatment can eliminate, prevent or limit the amount of heart muscle damage. [more]

Although not true "heart" disorders, strokes are a related condition. While some strokes occur when a blood vessel bursts, most strokes happen for the same reasons as a heart attack, clogged or blocked vessels.All strokes pose serious health threats.

Heart Failure When the heart muscle is too weak to effectively pump blood through the body, heart failure, or cardiomyopathy, sets in. Early diagnosis and treatment can stop or slow progression of heart failure. [more]

Heart Valve Problems Heart valve problems can be inherited or can develop and can wreak havoc on the heart’s ability to push blood from chamber to chamber.Medication and surgery are treatment options.

Do you know your EF? If you don't, ask your doctor. It could save your life.
If you have had a heart attack, take our quiz to learn if you may be at high risk for sudden cardiac arrest.


Heart Guide

Substances That Can Cause Heart Rhythm Disorders

Thousands of substances have the potential to affect the heart’s electrical system and alter its ability to pump blood through the body. Many illegal, prescription and over-the-counter drugs, as well as alcohol, tobacco, certain foods and other substances, can affect the electrical signals that stimulate the heartbeat.

Caffeine, Diet and Heart Arrhythmias
Caffeine is the most common substance associated with heart arrhythmias. Some people feel heart palpitations when they drink coffee or tea or eat chocolate. Red wine and eating too much can bring about symptoms in others. These rhythm problems are rarely serious.

Substance Abuse: Drugs and Inhalants
Abusing legal or illegal drugs can lead to dangerous arrhythmias.

Small amounts (less than one drink a day) of alcohol may reduce the incidence of heart problems and increase “good” cholesterol (HDL cholesterol). But, for some people, alcohol can create heart rhythm disturbances. Alcohol abuse is a major risk factor for high blood pressure, cardiomyopathy, heart failure and stroke.

Tobacco causes more heart and blood vessel disease, stroke and heart-related deaths than all illegal drugs combined. It contributes to as much as one-third of all cardiovascular disease.


Dietary Supplements & Over-the-Counter Medications
Some herbs and other substances used in over-the-counter remedies are believed to improve abnormal heart rhythms. Others can make them worse or interfere with heart medications. Diet pills can be especially problematic. Patients should always consult their healthcare provider before taking any medication or supplement.

Prescription Drugs
While most medicines prescribed by physicians are beneficial to health, occasionally side effects can be detrimental. Certain medications commonly prescribed for arrhythmias, heart disease and high blood pressure can themselves cause heart problems, including rhythm disturbances. The best course of action for patients is to be aware of symptoms and work closely with a physician.

Substances in the Environment & Workplace
Hundreds of substances in the environment can cause arrhythmias, heart disease and death. In general, people at greatest risk are those who handle or come into contact with dangerous substances in the workplace.

A few of the substance that can cause problems are: automobile emissions, cigarette smoke, pollution from industrial plants, paint thinners and propane gas.

Have you had a Heart Attack?

Do you know your EF?



Heart Guide
Risk Factors And Prevention

Even people who appear healthy and free of heart disease can experiment arrhythmias. But, those with heart disease are at the highest risk. So, reducing heart disease is key to reducing arrhythmia. Since the underlying cause of an arrhythmia isn’t always clear, the best course of action is preventing, delaying and treating heart problems such as atherosclerosis (“clogged” arteries) and high blood pressure.

Arrhythmia Prevention
Prevention falls into two main categories: preventing heart disorders in general and monitoring and treating any existing heart problems.

Preventing Heart Disorders
Treat or, when possible, eliminate risk factors that may lead to cardiovascular disease or cardiac arrhythmias.

  • Make healthy lifestyle choices. Living a “heart healthy” life is the best way to decrease the chances of developing heart disorders. Exercising regularly and eating a healthy, low-fat diet with plenty of vegetables, fruits and other vitamin-rich foods are the cornerstones of “heart healthy” living.
  • Maintain a healthy weight
  • Stop smoking and avoid secondhand smoke. Tobacco contributes to as much as one-third of all cardiovascular disease.
  • Avoid or limit the intake of caffeine, alcohol and other substances that may contribute to arrhythmias or heart disease.
  • Avoid unnecessary stress, such as anger, anxiety or fear, and find ways to manage or control stressful situations that cannot be avoided.
  • Have regular physical exams and promptly report any unusual symptoms to a physician.
  • Seek treatment for underlying health problems that may contribute to arrhythmias and heart disease. Problems include atherosclerosis (“clogged” arteries), heart valve damage, high blood pressure, high cholesterol, diabetes and thyroid disease.

Monitoring and Treating Existing Heart Disorders
Effectively treating any existing heart disorder is the best way to prevent it from becoming more severe.

  • Have regular check ups.
  • Understand how various conditions increase the risk of arrhythmias.
  • Learn about heart disorders, tests and treatment options, and discuss them with caregivers.
  • Find out if the heart's electrical system and its ability to pump blood efficiently have been affected by heart muscle damage from a heart attack or another cause.
  • Learn the importance of an ejection fraction (EF). EF is a measure of the proportion, or fraction, of blood the heart pumps out with each beat. An abnormally low EF is the single most important factor in predicting the risk of sudden cardiac death.
  • Follow treatment plans, and take all medications as prescribed.
  • Report any new symptoms or changes in existing symptoms to physicians as soon as possible.

Heart Tests

Because of the complexity of the heart’s electrical system, diagnosing heart arrhythmias can be difficult and requires special expertise as well as unique testing equipment. To diagnose the problem, a physician will carry out a thorough physical exam and gather a medical history. Taking into account a number of factors, including symptom patterns, the physician then will order specific tests

Diagnostic Tests
Electrocardiogram (ECG/EKG)

A special recording machine is attached to legs, arms and chest via 10 electrodes and takes a snapshot of the electric signals creating heart rhythms. [more]

A special imaging machine with a microphone-like attachment creates a videotaped image of heart structures that shows the heart’s four chambers, valves and movements. [more]

Holter Monitoring
To detect irregular heart rhythms, patients wear a Walkman-size recording box attached to their chest by five adhesive electrode patches for 24-48 hours.

Event Recorder
Patients carry a pager-sized event recording box so they can make a one- to two-minute recording of their heart rhythm when they actually experience symptoms. This is useful for patients with relatively infrequent and brief symptoms.

Tilt Table Test
This test evaluates the potential reasons for fainting, or syncope. Heart rhythm and blood pressure are carefully monitored while a patient rests on a special table. The table tilts the patient upright at a 70-80 degree angle for 30-45 minutes. If the patient faints, it usually means that he or she has a condition called vasovagal or neurocardiogenic fainting, which is not life threatening. [more]

Electrophysiology Study (EPS)
Under sterile conditions, thin tubes called electrode catheters are inserted into veins in the groin or neck area and threaded into the heart. The heart's electrical conduction system is measured. Electrical impulses are applied to the heart to provoke and analyze a fast heart rate. This study can diagnose symptomatic and potentially life-threatening slow and fast heart rates. [more]

Radionuclide Ventriculography
Also called the first pass technique, or Multiple-Gated Acquisition Scanning (MUGA), radionuclide ventriculography is a nuclear medicine test that measures the heart's pumping ability.

Cardiac Catheterization
A thin hollow tube called a catheter is inserted through a blood vessel and, under X-ray guidance, threaded to the heart in cardiac catheterization. The catheter can obtain tissue samples of heart muscle that may be damaged, measure the pressure in the heart, or diagnose blood vessel or heart valve disease.



The underlying cause of an arrhythmia provides the basis for selecting the best treatment. Treatments fall into several main categories along a continuum from the least to most invasive. In general, the least invasive treatment that effectively controls the arrhythmia is the treatment of choice. Options including lifestyle changes, medication, devices, ablation procedures, and surgery, including the implantation of pacemakers and defibrillators.

Lifestyle Changes
Since other heart disorders increase the risk of developing arrhythmias, lifestyle changes often are recommended. In addition, improving health can lesson the symptoms of arrhythmias and other heart disorders as well as prove beneficial to overall patient health.

Medications can control abnormal heart rhythms or treat related conditions such as high blood pressure, coronary artery disease, heart failure and heart attack. Drugs also may be administered to reduce the risk of blood clots in patients with certain types of arrhythmias. [more]

Electronic Devices
By delivering a controlled electric shock to the heart, defibrillators or cardioverters "shock" the heart back into a normal heart rhythm.

Sometimes the devices are external, such as in an emergency situation. Often, the electronics are implanted in the patient’s chest.

Implanted Cardioverter Defibrillators (ICDs)
ICDs are 99 percent effective in stopping life-threatening arrhythmias and are the most successful therapy to treat ventricular fibrillation, the major cause of sudden cardiac death. ICDs continuously monitor the heart rhythm, automatically function as pacemakers for heart rates that are too slow, and deliver life-saving shocks if a dangerously fast heart rhythm is detected. [more]

Devices that “pace” the heart rate when it is too slow (bradycardia) can take over for the heart’s natural pacemaker, the sinoatrial node, when it is functioning improperly. Pacemakers monitor and regulate the rhythm of the heart and transmit electrical impulses to stimulate the heart if it is beating too slowly. [more]

Devices for Heart Failure
The U.S. Food and Drug Administration (FDA) recently approved a special type of pacemaker for certain patients with heart failure. In Cardiac Resynchronization Therapy, an implanted device paces both the left and right ventricles (lower chambers) of the heart simultaneously.This resynchronizes muscle contractions and improves the efficiency of the weakened heart. [more]

Cardiac Ablation
In this procedure, one or more flexible, thin tubes (catheters) are guided via x-ray into the blood vessels and directed to the heart muscle. A burst of radiofrequency energy destroys very small areas of tissue that give rise to abnormal electrical signals. [more]

Although surgery is sometimes used to treat abnormal heart rhythms, it is more commonly elected to treat other cardiac problems, such as coronary artery disease and heart failure. Correcting these conditions may reduce the likelihood of arrhythmias.

Frequently Asked Questions
  • What are the major risk factors for heart disease?
  • What is high blood pressure and how is it treated?
  • What is cholesterol and why is it so important?
  • What are triglycerides?
  • What is atherosclerosis?
  • What is coronary bypass surgery?
  • Besides coronary bypass surgery, what other treatment options are available to a patient with narrowed or blocked arteries?
  • What is arrhythmia?
  • What is atrial fibrillation?
  • What is a pacemaker and how does it work?
  • What is mitral valve prolapse?
  • What is congestive heart failure?
  • What does the term "enlarged heart" mean?
  • What is cardiac catheterization?
  • What is a thallium stress test?
  • What is an EPS?
  • What is the difference between a "beta blocker" and a "clot buster?"
  • What is carotid artery disease?
  • What is an aneurysm and how is it treated?
  • What is a stroke and what are the warning signs of stroke?


1. What are the major risk factors for heart disease?

The major risk factors for heart disease are smoking, high cholesterol levels, high blood pressure, physical inactivity, obesity, diabetes, age, gender, and heredity (including race).

See also on this site: Heart Disease Risk Factors

2. What is high blood pressure and how is it treated?

Your heart pumps blood through a network of arteries, veins, and capillaries. The moving blood pushes against the arterial walls, and this force is measured as blood pressure.

High blood pressure results from the tightening of very small arteries (arterioles) that regulate the blood flow through your body. As these arterioles tighten (or constrict), your heart has to work harder to pump blood through the smaller space, and the pressure inside the vessels grows.

High blood pressure is so dangerous because it often has no symptoms. High blood pressure tends to run in families. Men are at higher risk than women, and blacks are at greater risk than whites.

In most cases, high blood pressure can be controlled by eating a low-fat and/or low-salt diet; losing weight, if necessary; beginning a regular exercise program; learning to manage stress; quitting smoking; and drinking alcohol in moderation, if at all. Medicines, called antihypertensives, are available if these changes do not help control your blood pressure within 3 to 6 months.

See also on this site: High Blood Pressure (Hypertension)

3. What is cholesterol and why is it so important?

Cholesterol is a fat-like substance (lipid) found in all body cells. Your liver makes all of the cholesterol your body needs to form cell membranes and make certain hormones. Extra cholesterol enters your body when you eat foods that come from animals (meats, eggs, and dairy products). Although we often blame the cholesterol found in foods that we eat for raising blood cholesterol, the main culprit is saturated fat, which is also found in our food. So, we should limit foods high in cholesterol or saturated fat. Foods rich in saturated fat include butter fat in milk products, fat from red meat, and tropical oils such as coconut oil.

Cholesterol travels to cells through the bloodstream in special carriers called lipoproteins. Two of the most important lipoproteins are low-density lipoprotein (LDL) and high-density lipoprotein (HDL). Doctors look at how LDL and HDL relate to each other and to total cholesterol.

LDL particles deliver cholesterol to your cells. LDL cholesterol is often called "bad cholesterol" because high levels are thought to lead to the development of heart disease. Too much LDL in the blood causes plaque to form on artery walls, which starts a disease process called atherosclerosis. When plaque builds up in the coronary arteries that supply blood to the heart, you are at greater risk for having a heart attack.

HDL particles carry cholesterol from your cells back to your liver, where it can be eliminated from your body. HDL is known as "good cholesterol" because high levels are thought to lower your risk for heart disease.

See also on this site: Cholesterol

4. What are triglycerides?

Triglycerides are fats that provide energy for your muscles. Like cholesterol, they are delivered to your body's cells by lipoproteins in the blood. If you eat foods with a lot of saturated fat or carbohydrates, you will raise your triglyceride levels. Elevated levels are thought to lead to a greater risk for heart disease, but scientists do not agree that high triglycerides alone are a risk factor for heart disease.

Although triglycerides serve as a source of energy for your body, very high levels can lead to diabetes, pancreatitis, and chronic kidney disease. As triglyceride levels rise, HDL levels fall, which may help explain why people with high triglycerides appear to have an increased risk for heart disease.

See also on this site: Cholesterol

5. What is atherosclerosis?

Atherosclerosis is a condition where a waxy substance forms inside the arteries that supply blood to your heart. This substance, called plaque, is made of cholesterol, fatty compounds, calcium, and fibrin (a blood-clotting material). Scientists think atherosclerosis begins when the very inner lining of the artery (the endothelium) is damaged. High blood pressure, high levels of cholesterol, fat, and triglycerides in the blood, and smoking are believed to lead to the development of plaque.

Atherosclerosis may continue for years without causing symptoms.

See also on this site: Coronary Artery Disease

6. What is coronary bypass surgery?

Bypass surgery improves the blood flow to the heart with a new route, or "bypass," around a section of clogged or diseased artery.

The surgery involves sewing a section of vein or artery from the leg or chest (called a graft) to bypass a part of the diseased coronary artery. This creates a new route for blood to flow, so that the heart muscle will get the oxygen-rich blood it needs to work properly.

Coronary bypass surgery has proved safe and effective for many patients who have the procedure. You can expect to stay in the hospital for about a week after surgery, including at least 1 to 3 days in the Intensive Care Unit (ICU). Your doctor may also recommend that you participate in a cardiac rehabilitation program. These programs are designed to help you make lifestyle changes like starting a new diet and exercise program, quitting smoking, and learning to deal with stress.

See also on this site: Coronary Bypass Surgery

7. Besides coronary bypass surgery, what other treatment options are available to a patient with narrowed or blocked arteries?

A severely narrowed coronary artery may need treatment to reduce the risk of a heart attack. Coronary bypass surgery is one form of treatment, but there are other therapies that have been found effective among carefully selected patients.

Angioplasty, which opens narrowed arteries, is performed by interventional cardiologists. They use a small balloon-tipped catheter that they inflate at the blockage site to flatten the plaque against the artery wall. A thin wire is inserted into an artery in the leg and is guided to the site of narrowing in the coronary artery. The catheter is slipped over this guidewire and positioned at the blockage, where the balloon is inflated. After treatment, the wire, catheter, and balloon are removed. The hospital stay and recovery time for this procedure are shorter than that of bypass. But, about 35% of patients are at risk for more blockages in the treated area (called restenosis). If restenosis is going to occur, it will usually happen within 6 months of the procedure.

A stent procedure is used in conjunction with balloon angioplasty. It involves implanting a mesh-like metal device into an artery at a site narrowed by plaque. The stent is mounted on a balloon-tipped catheter, threaded through an artery, and positioned at the blockage. The balloon is then inflated, opening the stent. Then, the catheter and deflated balloon are removed. The opened stent keeps the vessel open and stops the artery from collapsing. Restenosis rates are generally around 15-20%.

Atherectomy may be an option for certain patients who cannot have balloon angioplasty. A high-speed drill on the tip of a catheter is used to shave plaque from artery walls.

Laser ablation uses a catheter that has a metal or fiberoptic probe on the tip. The laser uses light to "burn" away plaque and open the vessel enough so that a balloon can further widen the opening.

Percutaneous transmyocardial revascularization (PTMR) is performed by a cardiologist in the cardiac catheterization laboratory. Using local anesthesia, the cardiologist inserts a long, thin tube (called a catheter) in an artery in the leg that leads to the heart. A laser is then fed through the catheter and used to create tiny holes in the heart muscle. These holes become channels for blood to flow to oxygen-starved areas of the heart. Researchers believe that the procedure may cause new vessels to form, reducing the pain of angina. PTMR is currently being used on patients who have not responded to other treatments such as medicines, angioplasty, or coronary artery bypass surgery.

See also on this site: Coronary Artery Disease

8. What is arrhythmia?

Arrhythmias are irregular heartbeats caused by a disturbance in the electrical activity that paces your heartbeat. Arrhythmias cause nearly 340,000 deaths each year. Almost everyone's heart skips a beat at one time or another. These mild, one-time palpitations are harmless. But there are more than 4.3 million Americans who have recurrent arrhythmias, and these people should be under the care of a doctor.

Arrhythmias can be divided into two categories: ventricular and supraventricular. Ventricular arrhythmias happen in the heart's two lower chambers, called the ventricles. Supraventricular arrhythmias happen in the structures above the ventricles, mainly the atria, which are the heart's two upper chambers.

Arrhythmias are further defined by the speed of the heartbeats. A very slow heart rate, called bradycardia, means the heart rate is less than 60 beats per minute. Tachycardia is a very fast heart rate, meaning the heart beats faster than 100 beats per minute.

See also on this site: Arrhythmia

9. What is atrial fibrillation?

Atrial fibrillation is a fast, irregular rhythm where single muscle fibers in your heart's upper chambers twitch or contract. According to the American Heart Association (AHA), atrial fibrillation is a major cause of stroke, especially among older people. This irregular rhythm may cause blood to pool in the heart's upper chambers. The pooled blood can lead to clumps of blood called blood clots. A stroke can occur if a blood clot travels from the heart and blocks a smaller artery in the brain (a cerebral artery).

See also on this site: Categories of Arrhythmia

10. What is a pacemaker and how does it work?

A pacemaker is a surgically implanted device that helps to regulate your heartbeat. Pacemakers use batteries to produce electrical impulses that make the heart pump. The impulses flow through tiny wires (called leads) that are attached to the heart. The impulses are timed to flow at regular intervals.

Most pacemakers work only when they are needed. These are called demand pacemakers. They have a sensing device that either shuts off the pacemaker if the heartbeat is above a certain rate or turns the pacemaker on when the heart is beating too slowly.

Pacemaker batteries can last up to five years or longer. Pacemakers and batteries can be replaced during a minor surgical procedure.

See also on this site: Pacemakers

11. What is mitral valve prolapse?

The mitral valve regulates the flow of blood from the upper-left chamber (the left atrium) to the lower-left chamber (the left ventricle). Mitral valve prolapse (MVP) means that one or both of the valve flaps (called cusps or leaflets) are enlarged, and the flaps' supporting muscles are too long. Instead of closing evenly, one or both of the flaps collapse or bulge into the atrium. MVP is often called click-murmur syndrome because when the valve does not close properly, it makes a clicking sound and then a murmur.

MVP is one of the most common forms of valve disease. It happens more often in women and tends to run in families. Most of the time, MVP is not a serious condition. Some patients say they feel palpitations (like their hearts skip a beat) or sharp chest pain. If you have MVP, you should talk to your doctor about taking antibiotic medicine before dental procedures or general surgery, especially if you have mitral regurgitation or thickened valve leaflets. This medicine will prevent infection of the valve.

See also on this site: Mitral Valve Prolapse

12. What is congestive heart failure?

Heart failure means your heart is not pumping as well as it should to deliver oxygen-rich blood to your body's cells.

Congestive heart failure (CHF) happens when the heart's weak pumping action causes a buildup of fluid (called congestion) in your lungs and other body tissues. CHF usually develops slowly. You may go for years without symptoms, and the symptoms tend to get worse with time. This slow onset and progression of CHF is caused by your heart's own efforts to deal with its gradual weakening. Your heart tries to make up for this weakening by enlarging and by forcing itself to pump faster to move more blood through your body.

Many therapies can help to ease the workload of your heart. Treatment options include lifestyle changes, medicines, transcatheter interventions, and surgery.

See also on this site: Congestive Heart Failure

13. What does the term "enlarged heart" mean?

An enlarged heart means the heart is larger than normal due to heredity, or disorders and diseases such as obesity, high blood pressure, and viral illnesses. Sometimes doctors do not know what makes the heart enlarge.

See also on this site: Dilated Cardiomyopathy

14. What is cardiac catheterization?

Cardiac catheterization is the method doctors use to perform many tests available for diagnosing and for treating coronary artery disease. Cardiac catheterization is used with other tests such as angiography and electrophysiology studies (EPS).

The method involves threading a long, thin tube (called a catheter) through an artery or vein in the leg or arm and into the heart. Depending on the type of test your doctor has ordered, different things may happen during cardiac catheterization. For example, a dye may be injected through the catheter to see the heart and its arteries (a test called angiography), or electrical impulses may be sent through the catheter to study irregular heartbeats (tests called electrophysiology studies).

See also on this site: Cardiac Catheterization

15. What is a thallium stress test?

A stress test is a common test that doctors use to diagnose coronary artery disease. The test helps doctors see how the heart is working. A thallium stress test is a nuclear study in which a radioactive substance is injected into your bloodstream to show how blood flows through your arteries. Doctors can see if parts of the heart muscle are damaged or dead, or if there is a serious narrowing in an artery.

See also on this site: Nuclear (Thallium) Stress Test

16. What is an EPS?

Electrophysiology (EPS) studies use cardiac catheterization techniques to study patients who have irregular heartbeats (called arrhythmias). EPS shows how the heart reacts to controlled electrical signals. These signals can help doctors find out where in the heart the arrhythmia starts and what medicines will work to stop it. EPS can also help doctors know what other catheter techniques could be used to stop the arrhythmia.

EPS uses electrical signals to help doctors find out what kind of arrhythmia you have and what can be done to prevent or control it. Doctors will perform a cardiac catheterization procedure in which a long, thin tube (called a catheter) will be put into an artery in your leg and threaded into your heart. This catheter can be used to send the electrical signals into your heart. Stimulating the heart will cause an arrhythmia, and doctors can record where in the heart it started. In some cases, you might be given a medicine to cause an arrhythmia. Certain medicines can also be given through the catheter to see which ones will stop the arrhythmia.

See also on this site: Electrophysiology (EPS) Studies

17. What is the difference between a "beta blocker" and a "clot buster?"

A beta blocker is a medicine that limits the activity of a hormone called epinephrine. Epinephrine increases blood pressure and heart rate. So, beta blockers work by limiting the activity of epinephrine, which, in turn, lowers your blood pressure and decreases your heart rate.

Clot busters are thrombolytic agents that may be given if you are having a heart attack or an ischemic stroke (a stroke caused by a blood clot). The term thrombolysis means to dissolve a clot, and that is exactly what these medicines do. In some cases, these medicines can dissolve a clot within minutes.

Clot busters work best when given right away. Some studies have shown that the medicines may offer little benefit if they are given more than a few hours after the first symptoms of a heart attack or ischemic stroke.

See also on this site: Medicines for Cardiovascular Disease

18. What is carotid artery disease?

Carotid artery disease is a form of disease that affects the vessels leading to the head and brain (cerebrovascular disease). Like the heart, the brain's cells need a constant supply of oxygen-rich blood. This blood supply is delivered to the brain by the 2 large carotid arteries in the front of your neck. If these arteries become clogged or blocked, you can have a stroke.

Carotid artery disease is usually caused by atherosclerosis, which is a hardening and narrowing of the arteries. As we age, fat deposits, cholesterol, calcium, and other materials build up on the inner walls of the arteries. This build-up forms a wax-like substance called plaque. As the plaque builds up, the arteries become narrower, and the flow of blood through the arteries becomes slower.

Lifestyle changes, medicines, transcatheter interventions, or surgery can be used to treat carotid artery disease and lower your risk of a stroke.

See also on this site: Carotid Artery Disease

19. What is an aneurysm and how is it treated?

An aneurysm is a balloon-like bulge in a blood vessel that can affect any large vessel in your body. An aneurysm happens when the pressure of blood passing through part of a weak blood vessel forces the vessel to bulge outward, forming what you might think of as a thin-skinned blister. Not all aneurysms are life threatening, but those found in the arteries in our bodies often need to be treated. If the bulging stretches the artery too far, this vessel may burst, causing a person to bleed to death.

Aneurysms can occur in blood vessels anywhere in the body. They usually form in the brain or in the aorta (the main artery carrying blood from the heart). In many cases, aneurysms are associated with other types of cardiovascular disease, especially high blood pressure and atherosclerosis. Traumatic injuries, infections, and congenital conditions can also lead to an aneurysm.

Treatment depends on the size and location of your aneurysm and your overall health. Aneurysms in the upper chest (ascending aorta) are usually operated on right away. Aneurysms in the lower chest or the area below your stomach (descending thoracic and abdominal portions of the aorta) may not be as life-threatening. Aneurysms in these locations are watched regularly. If they become about 5 cm (almost 2 inches) in diameter, continue to grow, or begin to cause symptoms, your doctor may want you to have surgery to stop the aneurysm from bursting.

Doctors also may prescribe medicine, especially medicine that lowers blood pressure (such as a beta blocker), to relieve the stress on the arterial walls. Medicine to lower blood pressure is especially useful for patients where the risk of surgery may be greater than the risk of the aneurysm itself.

Cardiologists at the Texas Heart Institute have been using a nonsurgical technique to treat high-risk patients with aortic aneurysms. This technique is useful for patients who cannot have surgery because their overall health would make it too dangerous. The procedure uses a balloon-tipped catheter to insert a spring-like device called a stent at the site of the aneurysm. The balloon is inflated to open up the stent, and once the catheter and deflated balloon are removed from the artery, the stent acts as a barrier between the blood and the arterial wall. The blood flows through the stent, decreasing the pressure on the wall of the weakened artery. This decrease in pressure can prevent the aneurysm from bursting.

See also on this site: Aneurysms

20. What is a stroke and what are the warning signs of stroke?

A stroke is an injury to the brain that may also severely affect the body. A stroke happens when blood supply to part of the brain is cut off or when there is bleeding into or around the brain. This can happen if a blood clot blocks an artery in the brain or neck or if a weakened artery bursts in the brain.

Risk factors for stroke include high blood pressure, smoking, heart disease, diabetes, and a high red blood cell count. The risk of stroke also increases with age. Heavy alcohol use increases your risk of bleeding (hemorrhagic) strokes.

The warning signs for stroke may include a sudden, temporary weakness or numbness in your face or in your arm or leg; trouble talking or understanding others who are talking; temporary loss of eyesight, especially in one eye; double vision; unexplained headaches or a change in headache pattern; temporary dizziness or staggering when walking; or a transient ischemic attack (TIA).


Glossary Cardiology Terms

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Acidosis - A lowering of the pH in blood tissue due to excessive acid caused by circulation failure or severe lack of oxygen.

Aneurysm - A balloon-like sac in the wall of an artery, vein, or heart caused by a weakening of the wall by injury, disease, or abnormality present at birth.

Angiocardiography - An x-ray method using dye in the bloodstream to show the dimension of the heart.

Angioplasty - A procedure using a deflated balloon on the end of a catheter used to widen narrow arteries.

Antiarrhythmic drugs - Medicines used to treat heart rate rhythm disorders. Frequently used drugs include: lidocaine, procaine, amide, digitalis, propanolol, quinidine, alroprine, and isoproterenol.

Antibody - A substance produced by the immune system to fight infections and foreign substances. Antibodies are produced in response to specific antigens.

Anticoagulant - A drug that delays clotting but does not dissolve existing clots. Tends to prevent new clots from forming on artificial valves and existing clots from enlarging.

Antigen - Substances recognized by the immune system as infectious or foreign. The immune system produces antibodies to fight antigens.

Aorta - The main artery which receives blood from the left ventricle of the heart and flows to the body.

Aortic valve - The heart valve between the aorta and the left ventricle.

Arrhythmia - An abnormal rhythm of the heart.

Arteriography - An x-ray opaque dye injected into the blood stream to study arteries (usually coronary) for damage.

Artery - One of the series of vessels that carries blood from the heart.

Atresia - The failure of a bodily structure to develop and the tissue to fully close as it normally would. Usually present and open at birth.

Atria - (atrium-singular) The two upper holding chambers of the heart.

Atrial Septal defect - A congenital defect in the atrial septum.

Atrial Septum - The wall dividing the right and left atria.

Atrioventricular node - Conducting tissue at the bottom of the right atrium in which electrical impulses must pass to reach the ventricles.

Atrioventricular canal defect (A-V Canal defect) - Also atrioventricular septal defect or endocardial cushion defect. A congenital defect in which defects are present between the atria and ventricles and the tricuspid and mitral valves are abnormal.

Azathioprine - An anti-rejection drug given to transplant patients that suppresses the production of white blood cells.


B Cell - A certain kind of white blood cell that plays a central role in antibody production.

Bacterial endocarditis - A bacterial infection of the inner layer of the heart.

Balloon catheter - Used to dilate a narrow structure. (see angioplasty)

Biopsy - The removal and examination of tissue for diagnosis.

Blood pressure - The pressure exerted by the heart in pumping blood.

Blue babies - A result of insufficient oxygen in the arterial blood. Can be caused by a heart defect, premature birth, or poor respiration.

Bradycardia - An unusually slow heart rate.

Bundle of His - Named after Wilhelm His, an A-V bundle or atrioventricular bundle of small mass fibers. The only known direct connection between the ventricles and the atria that conducts impulses to the ventricular heart muscle.


Cardiac - Relating to the heart.

Cardiac arrest - The blood ceases to circulate and the heart stops beating.

Cardiac Catheterization - putting a catheter into an artery or vein to examine the heart sometimes using a fluoroscope to view the heart.

Cardiologist - A doctor specializing in the diagnosis and treatment of heart disorders.

Cardiopulmonary Resuscitation (CPR) - Used when the heart stops beating, a method of mouth-to-mouth breathing and external cardiac compression to keep oxygenated blood circulating.

Catheter - A fine, flexible tube which is inserted into an artery or vein. It is made of material to which blood will not adhere.

Catheterization - The process of inserting a catheter into a vein or artery and guiding it through the heart chambers and surrounding vessels for purposes of examination or treatment.

Cineangiocardiography - A similar procedure to angiocardiography except that this method uses motion pictures instead of x-ray slides.

Closed heart surgery - Performed on blood vessels in the chest but not in the heart. Does not require a heart-lung machine.

Coarctation - A narrowing of the aorta where the aorta and pulmonary arteries are joined by the ductus arteriosus.

Collateral Circulation - A network of small arteries normally closed. When the coronary artery is blocked, they may open to carry blood to the heart.

Congenital - Existing at birth.

Congestive heart failure - The inability for the heart to pump the blood out of the heart. The build up of fluid on lungs and tissue can be acute or gradual.

Corticosteroids - Hormones naturally produced by the body which can also be manufactured synthetically. High doses of corticosteroids will suppress the immune system. See Prednisone.

Crossmatching - The testing of blood samples to determine the compatibility of a potential donor's and a recipient's blood.

Cyanosis - Caused by insufficient oxygen. Causes a blueness to the skin, lips, and nail beds.

Cyclosporine - A immunosuppressive drug made from soil molds and is taken by the vast majority of transplant recipients. The product name of the first generation of cyclosporine was Sandimmune. Most patients now take the second generation, called Neoral.


Defibrillator - A machine to stabilize normal contraction rhythms.

Dextrocardia - Abnormal position of the heart within the chest. The heart is usually on the left, and in this condition it is on the right.

Diastolic - The bottom of the two blood pressure numbers. Measures the heart at rest.

Digitalis (Digoxin)- A medicine that slows heart rate, strengthens contractions, and helps move fluid away from the body tissues.

Diuretic - A drug that increases the excretion of urine.

Ductus arteriosus - An open artery that connects the aorta and pulmonary artery before birth. Normally closes after birth but if it doesn't, then surgery or medical treatment may be required.


Echocardiography - A procedure in which pulses of sound are transmitted into the body and the echoes from the heart are recorded and charted. The Doppler color flow gives a picture to show the direction of blood flow.

Edema - Swelling due to excessive fluid in the body.

Electrocardiogram (EKG) - A print-out of the electrical impulses produced by the heart.

Endocardium - The inner lining of the wall of the heart.

Extrasystole - A form of arrhythmia often referred to as "an extra heartbeat".


Fibrillation - When the heart muscle fibers contract individually and quickly disabling the heart from pumping effectively.

Fluoroscope - A tool for looking at internal organs.

Foramen ovale - An opening between the right and left upper chambers of the heart. Closes after birth.


Gingival Hypertrophy - Swelling and thickening of the gums. A common side effect of the immunosuppressive drug cyclosporine.

Graft - A transplanted tissue or organ.


Heart block - The electrical impulses causing the heart to beat are slowed or blocked along the pathway between the upper and lower chambers, and usually requires a pacemaker.

Heart-lung machine (cardiopulmonary bypass) - An instrument that oxygenates and pumps the blood during open-heart surgery.

Helper T Cell - A specialized white blood cell that calls upon other parts of the immune system to fight an infection or foreign material.

Heparin - A medicine used to slow the clotting of the blood.

Heterotaxy - Abnormal structure of the heart and other abdominal organs. Usually with multiple defects in the heart and the absence of or multiple spleens.

Holter monitoring - An instrument worn 24 to 72 hours at a time that records EKG information which is later analyzed for arrhythmias and other abnormalities.

Homograft - Also know as Allograft; a heart valve replacement using a human donor valve.

Hypertension - Blood pressure above the normal range.

Hypertrophy - When cells increase in size and cause enlarged tissues and organs.

Hypoplastic - An underdeveloped tissue or organ.

Hypotension - Low blood pressure.

Hypoxia - Low oxygen content in the body.


Immune Response - A defensive action by the immune system to an infection or foreign material.

Interrupted aortic arch - A severe form of coarctation of the aorta.

Invasive - Introduced into the body.

Ischemic heart disease - Ailments caused by a decreased blood supply due to narrowning of the coronary arteries.


Looping - When the looping of the heart is formed early in developmental stages of the fetus.


Mitral valve - The valve between the left ventricle and left atrium having two flaps or cusps that prevent backflow.

Murmur - The noise between normal heart sounds caused by blood flow.

Myocardium - The muscle of the heart wall that contracts to push blood out.


Open-heart surgery - An operation inside the heart while the patient is on a heart lung machine.

Oximetry - A method of measuring the oxygen content of blood.


Pacemaker - An electrical device used to cause heart contractions and control heartbeats.

Palpitations - Irregular heartbeats felt as a skip or momentary cessation of the heart,

Patent Ductus - A blood vessel present prior to birth that bypasses the lungs of the fetus. The Patent Ductus closes shortly after birth.

Patent Ductus Arteriosus - Failure of the Patent Ductus to close shortly after birth as it should.

Pericarditis - Inflammation of the membrane sac.

Pericardium - A membrane sac surrounding the heart and the vessels close to the heart.

Prednisone - A manufactured steroid commonly used as an immunosuppressive drug.

Pulmonary artery - The artery that carries blood to the lungs from the heart.

Pulmonary artresia - Failure of the pulmonary valve or pulmonary artery to develop in utero.

Pulmonary Hypertension - High blood pressure in the blood vessels of the lungs.

Pulmonary valve - The valve between the pulmonary artery and the right ventricle having three cusps that open and close with the heartbeat.


Rejection - An immune system response to a transplanted organ.

Right-heart flow defect - Affecting the ventricle valves and arteries of the right side early on in development.


Septum - The wall dividing the heart chambers.

Stenosis - An obstruction or narrowing of an opening or valve.

Systolic blood pressure - The pressure measured when the ventricle contracts. The highest of the pressures measured.


T Cell - Specialized white blood cells that destroy cells infected by viruses.

Tachycardia - Very quick heart rate.

Tetralogy of Fallot - A malformation where the right ventricle connects to the pulmonary artery causing pulmonary stenosis with a large ventricular septal defect.

Tissue Typing - A blood test used to evaluate the compatability of an organ donor's tissue with the tissue of a potential recipient.

Transplantation (heart) - The placement of a healthy heart from a donor to a patient when the patient's heart can no longer function adequately.

Tricuspid atresia - The failure of the development of the tricuspid valve.

Truncus arteriosus - The failure to divide the single artery in the embryo stage which would be the aorta and pulmonary arteries.


Valve conduit - Tubing used with artificial valves.

Ventricle - One of the lower pumping chambers of the heart.

Ventricular septum - The wall between the left and right ventricle. If the wall is not fully formed, a ventricular septal defect is present.

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