- Glossary -

A resource to further your cardiac knowledge

Use this helpful glossary to further your understanding of normal and abnormal heart functions, medical tests and procedures, and terminology related to the field of cardiology.

Abnormal heart rhythm – Also called dysrhythmias or arrhythmias, these abnormal rhythms can result in fast or low heart rates. There are several types of abnormal rhythms. Dysrhythmias may originate in the top chambers of the heart (the atria), for example: atrial fibrillation, atrial flutter, and supraventricular tachycardia. Some dysrhythmias come from the pumping (ventricular) chambers, such as ventricular tachycardia and fibrillation. Ventricular rhythm abnormalities may be particularly dangerous or lethal.

Anticoagulation – This refers to thinning of the blood with medication, usually with the pill warfarin (Coumadin®) or dabigatran (Pradaxa®). Several types of liquid blood thinners may be administered into a vein (intravenous) or injected under the skin (subcutaneous). These are most commonly prescribed in a hospital setting.

Atrial fibrillation – With this type of abnormal heart rhythm the heart beat is irregular. Commonly, the heart rate is fast without treatment, but occasionally may be slow. The lack of coordinated contraction of the atrial chambers may lead to sluggish blood flow and subsequent development of blood clots in the heart. Anticoagulation (thinning of the blood) is often prescribed.

Cardiac catheterization – In this procedure, the cardiologist inserts a thin tube into a leg or arm artery (and occasionally into a vein). Contrast dye is injected into the heart arteries and left ventricle to evaluate coronary artery blood flow and ventricular function, respectively. Cardiologists perform this procedure to evaluate chest pain, abnormal stress tests, congestive heart failure, valve disease, pericardial disease, and during a heart attack.

Cholesterol – Also known as lipids, there are several different types of cholesterol: some good (called high density lipoprotein or HDL) and others unhealthy (called low density lipoprotein or LDL). LDL cholesterol can be reduced by diet, exercise, and cholesterol-reducing medications.

Congestive heart failure – Patients with congestive heart failure (CHF) accumulate fluid within the lungs. Symptoms may include shortness of breath, fatigue, and leg swelling. CHF may occur as a consequence of weak heart, stiff heart, heart valve disease, coronary artery disease, and heart rhythm abnormalities.

Coronary artery disease – CAD is the accumulation of atherosclerotic plaque (from cholesterol, scar tissue, and inflammation) in the heart arteries. Rupture or fissuring of the plaque may lead to blood clot accumulation and result in a heart attack. Major risk factors are smoking, diabetes, high cholesterol, high blood pressure, and family history of CAD.

CT angiography – Computed tomography (CT) coronary angiography is a method of visualizing the blood vessels in the heart without performing an invasive study. It is limited by less resolution than traditional invasive cardiac catheterization. Iodine-based contrast dye is required.

Echocardiography – Echocardiography is an ultrasound technique to visualize cardiac structures. This procedure helps cardiologists assess the strength of the ventricles, evaluate for heart valve disease, and assess for fluid within the pericardial sac. It can be done in conjunction with stress testing.

Electrophysiology study – In this procedure, the electrical system of the heart is examined for the presence of abnormal rhythm. It is performed by placing long electrical wires into the heart. Ablation is a procedure done in conjunction with the electrophysiology study to treat certain types of rapid heart beats.

Hypertension – Hypertension is elevated blood pressure, which puts increased stress on organs and is a cause of stroke, heart attack, congestive heart failure, and kidney failure.

Implantable cardioverter defibrillators – ICDs treat rapid, life-threatening rhythms. The device is similar to (but larger than) a pacemaker. One or more wires are placed in the patient’s heart through blood vessels. The ICD can pace or shock fast heart rhythms and increase slow rates.

Myocardial infarction – Also known as a heart attack, myocardial infarction is caused by the severe decrease or absence of blood flow to the heart muscle, usually from blockage of a coronary artery by a blood clot and artery plaque.

Nuclear cardiology – Heart imaging studies have been developed to enhance the diagnostic capability of exercise or pharmacologic stress testing. Nuclear tracers are radioactive elements that are injected into the bloodstream and enter heart cells in proportion to the blood flow reaching those cells. The tracers give off radioactive particles, called photons, which can be detected and measured by a special camera. The cardiac blood supply is deemed to be normal if the heart muscle takes up maximum amounts of tracer. Heart muscle supplied by blocked arteries will exhibit lower amounts of tracer.

Pacemaker – A pacemaker is a device that treats slow heart rhythms. The small generator is surgically placed under the skin just below the collar bone, with one or two wires connected to the generator. Electrical impulses are delivered to maintain a minimum heart rate.

Pericardial disease – This disease affects the pericardium, the sac that surrounds the heart. The most common problem is pericarditis, inflammation of the pericardium, usually caused by viral infection. More serious is pericardial effusion, or fluid around the heart, that can lead to tamponade – a dangerous condition of high pressure around the heart. Constrictive pericarditis is an uncommon problem arising from a stiff pericardial sac.

Peripheral arterial disease – PAD is a blockage of an artery or arteries outside of the heart. It most often affects the arteries to the legs, carotid arteries to the brain, or kidney arteries. Major risk factors are smoking, diabetes, high cholesterol, and high blood pressure.

Stents and angioplasty – During cardiac catheterization, a blocked artery can be treated by expanding a balloon within the blockage to expand the vessel (percutaneous transluminal coronary angioplasty or PTCA). Stents are metal coils deployed after PTCA to help keep the artery open. Stents may be “bare” without a drug coating or may have a medication on the coils to prevent excess scar tissue. A drug-coated stent requires much longer treatment with medication to prevent a clot attaching to the stent.

Stress test – This diagnostic technique assesses a person’s cardiac and pulmonary function as well as exercise capacity. The typical stress test utilizes a treadmill and may be accompanied by imaging studies using echocardiography or nuclear perfusion testing to enhance the diagnostic capabilities of the test. The most common reason to do a stress test is to evaluate whether chest discomfort or shortness of breath is from a narrowing of a heart artery. For patients who are physically incapable of exercising on a treadmill, pharmacologic agents can simulate some of the aspects of exercise.

Valve disease – This disease involves excessive leaking (regurgitation) or tightness (stenosis) of the heart valves: aortic, mitral, tricuspid, and pulmonary valves.

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