Glossary of Heart Failure

Reviewed by: HU Medical Review Board | Last reviewed: November 2019


Ablation: A procedure to scar or destroy a section of heart tissue that allowed electrical signals to cause an abnormal heart rhythm.

ACE inhibitor (angiotensin-converting enzyme): A class of drugs that lower blood pressure, improve left the ventricular performance, and increase survival in heart failure patients. They work by relaxing the arteries and veins which permits blood to circulate at a more normal rate.

Angina: Chest pain or pressure caused by insufficient or restricted blood flow, resulting in reduced oxygen supply to the heart muscle.

Angiogram: A radiographic picture from an angiography that shows the size, shape, and location of the heart and the coronary arteries.

Angiography: An x-ray technique in which dye, sometimes called contrast, is injected into blood vessels to better visualize disease, pressure, and blood flow through the coronary arteries and chambers of the heart.

Angioplasty: The widening of a blocked or narrowed blood vessel to restore blood flow to the heart.

Antiarrhythmics: A class of drugs used to treat irregular heart rhythms.

Anticoagulant: A class of drugs, blood thinners, that slows the blood clotting process.

Antihypertensive: Medicines or other therapies designed to lower blood pressure.

Aorta: The largest artery in the body and the main vessel to supply oxygen-rich blood from the heart throughout the entire body.

Aortic Stenosis: An aortic valve that doesn’t open all the way, thereby restricting blood flow.

Aortic valve: One of four heart valves; it is a flap-like structure that regulates blood flow from the left ventricle into the aorta and prevents backflow into the heart.

ARB (Angiotensin II receptor blocker): A class of drugs that lowers blood pressure by blocking the action of angiotensin II, a chemical that causes the blood vessels to constrict.

Arrhythmia: An abnormal or irregular heart rhythm in which the heart can beat too fast, too slow, or irregularly.

Artery: A blood vessel that transport oxygen-rich blood from the heart to the body.

Arteriosclerosis: A “hardening of the arteries” which can cause artery walls to thicken.

Artificial heart: A man-made heart, sometimes called a total artificial heart (TAH), used to replace a diseased heart while a person is waiting for a transplant.

Atherosclerosis: The buildup of plaque, a fatty/waxy substance inside blood vessels, which causes the narrowing of the arteries and reduced blood flow.

Atria: The two upper chambers of the heart, the left atrium, and right atrium, that pump blood to the ventricles, the lower chambers of the heart.

Atrial Fibrillation (AF): A fast, disorganized heart rhythm caused by irregular electrical activity in the upper chambers of the heart (right or left atrium). AF can create a fluttering sensation in the chest.

Atrial Tachycardia (AT): An arrhythmia that starts in the upper chambers of the heart causing a very fast heart rate of over 160 beats per minute.

Atrioventricular (AV) node: A junction between the upper and lower chambers that conducts and regulates electrical impulses as they pass from the atria to the ventricles of the heart.


Balloon catheter:A long, flexible tube (catheter) with a small balloon on the end that can be threaded through an artery. It is used in performing angioplasty or valvuloplasty.

Balloon valvuloplasty: A procedure to repair a heart valve where a balloon-tipped catheter is threaded through an artery into the heart. When it reaches the valve, the balloon is inflated which can open and separate the stiffened flaps, called leaflets.

Beta-blocker: A class of drugs that decrease heart rate and blood pressure by reducing the activity of the hormone epinephrine. They are prescribed to treat heart failure, prevent chest pain and alleviate high blood pressure.

Blood clot: A gel-like mix of blood products formed by clotting factors in the blood. Clots stop the flow of blood from a wound and can form inside an artery if the walls are damaged or blocked by buildup.

Blood pressure: The force or pressure exerted by the heart when pumping blood through the arteries which supply the heart and body.

Bradycardia: An abnormally slow heart rate or pulse, normally less than 60 beats per minute.

Brain Natriuretic Peptide (BNP): BNP is an amino acid/peptide secreted by the heart’s ventricles. It’s measured by a blood test and helps in the evaluation of cardiac function. Elevated levels indicate damage to the heart.

Bridge to transplant: The process of using mechanical circulatory support with a VAD or Total Artificial Heart to keep heart failure patients alive while they await a heart transplant.

Bypass: A surgical procedure to improve blood flow by creating a new route; a “bypass” around a section of the clogged or diseased artery.


Calcium channel blocker: A type of drug that lowers blood pressure by regulating calcium-related electrical activity in the heart.

Cardiac amyloidosis: A condition caused by amyloid deposits, an abnormal protein in the heart tissue. Amyloidosis interferes with the normal working of the heart.

Cardiac arrest: Disruption of the electrical signals of the heart which causes the heart to suddenly stop beating. This can result in instant death because the blood has stopped flowing through the circulatory system.

Cardiac catheterization: A procedure that involves inserting a catheter, a flexible hollow tube, into an artery and passing it up into the heart. Often used as a part of other procedures, it enables visualization of the heart and blood vessels aiding in the diagnosis and treatment of heart disease.

Cardiac enzymes: Complex chemical elements which can speed up biochemical processes in the heart muscle. Elevated enzyme levels can indicate a current or past heart attack.

Cardiac Resynchronization Therapy (CRT): An implantable cardiac device used to synchronize the ventricles to a regular, normal pace using electrical impulses. CRT improves the mechanical activity of the ventricles. Sometimes called biventricular pacing, it helps the heart pump blood more efficiently by resynchronizing the contractions.

Cardiologist: A doctor who specializes in the treatment of the heart.

Cardiomyopathy: A medical term referring to structural damage to the myocardium. It can be classified as dilated (enlarged), hypertrophic (excessively thick myocardium), or restrictive (stiff myocardium).

Cardiopulmonary resuscitation (CPR): An emergency measure that can maintain breathing and heartbeat (circulatory) functions.

Cardiovascular: Related to the heart and blood vessels that are part of the circulatory system.

Cardiovascular Disease: Also known as heart disease, it is a general term referring to conditions affecting the heart and blood vessels.

Cardioversion: Restoration of normal sinus rhythm. It can be achieved by medication or the application of an electrical shock to the heart to convert an abnormal heartbeat to a normal rhythm.

Carotid artery: A major artery in the neck that supplies blood to the brain.

Cholesterol: A fatty substance produced by the body and present in foods, that in excess can contribute to atherosclerosis. Limited amounts are essential for the normal development of cell membranes.

Computerized tomography (CT or CAT): An imaging technique that uses a computer to create cross-sectional images that collectively produce pictures of an area of the body.

Compensated heart failure: A type of heart failure in which the damaged heart maintains sufficient cardiac output by using normal compensatory mechanisms.

Congenital: A condition present at birth.

Congenital heart defects: Malformation or other problems of the heart or major blood vessels present at birth.

Congestive heart failure: Occurs when the heart cannot sufficiently fill with or eject enough blood leading to a backup of blood and an accumulation of fluid in the body tissues, including the lungs.

Coronary arteries: The two arteries coming from the aorta that arch down over the top of the heart and then divide into branches to supply blood to the heart muscle.

Coronary artery bypass graft (CABG): A surgical procedure to reroute blood around a diseased vessel to supply blood to the heart. It is performed by creating a graft from a piece of vein or artery from elsewhere in the body.

Coronary artery disease (CAD): The narrowing of one or more of the arteries that supply blood to the heart. The condition results from a buildup of plaque and greatly increases the risk of a heart attack and is a leading cause of heart failure.

Coronary occlusion: The blockage of one of the coronary arteries that limit blood flow to the heart muscle.


Decompensated heart failure: A type of heart failure in which the damaged heart can no longer pump enough blood to supply the rest of the body. It is characterized by a relatively sudden worsening of heart failure.

Defibrillator: A device that delivers an electric shock to help restore a normal heart rhythm.

Diabetes (diabetes mellitus): A disease where the body can’t produce or properly use insulin. Insulin is needed to convert sugar and starch into energy. Diabetes is a common risk factor for developing heart failure.

Diastolic blood pressure: The bottom blood pressure number which measures the pressure in the arteries when the heart muscle is relaxed between beats.

Digitalis (or Digoxin): A drug used to treat congestive heart failure and heart rhythm problems, it is made from the leaves of the foxglove plant.

Diuretic: A drug class of drugs that helps eliminate fluids. It can be prescribed to alleviate water retention and bloating.

Dyspnea: Shortness of breath.


Echocardiogram: A non-invasive test and a diagnostic tool that uses ultrasound to examine the structure and function of the heart by analyzing sound waves. It can provide information on blood flow, the size, and shape of the heart, valves functioning, among other things.

Edema: Swelling caused by abnormal fluid accumulation in the body. In heart failure, edema can develop when pressure builds up in veins causing fluid to leak into the surrounding tissue.

Ejection fraction (EF): The percentage of blood pumped from the ventricles per heartbeat. It is used to evaluate the efficiency of the emptying of the left ventricle.

Electrocardiogram (ECG or EKG): A non-invasive test that measures the electrical activity in the heart by using sensors placed on the body to create a graphical representation.

Endocardium: The smooth membrane covering the inner lining of the heart.

Enlarged heart: A heart which is larger than normal. The condition can be caused by multiple different diseases.

Enzymes: A complex chemical capable of speeding up specific biochemical processes in the body.

Epicardium: The thin membrane covering the outside surface of the heart muscle.


Fibrillation: Rapid, uncoordinated contractions of the heart muscle which results in ineffective pumping.


Heart attack: Also known as myocardial infarction, it is the death of, or damage to, part of the heart muscle caused by a lack of oxygen-rich blood supply to the heart.

Heart failure: A chronic, progressive syndrome where the heart can no longer sufficiently pump enough blood to meet the demands of the body.

High blood pressure (hypertension): A persistent increase in blood pressure above its normal range. Normal blood pressure is approximately 120/80 mmHg for healthy adults.

Holter monitor: A portable device for recording heartbeats over a period of 24 hours or more.

Hormones: Chemicals released into the bloodstream that control different body functions including metabolism, growth, sexual development, and responses to stress or illness.

Hypertrophy: The enlargement of tissues or organs because of increased workload.


Immunosuppressants: A class of drugs that suppress the body’s immune system. These medicines are used after organ transplants to minimize the chances that the body will reject the newly transplanted organ, such as a heart.

Implantable Cardiac Defibrillator (ICD): A surgically implanted device that can monitor and respond to certain types of abnormal heart rhythms. It works by sending electrical shocks to the heart to stop fast, and potentially deadly, heart rhythms.

Incompetent valve: Known also as insufficient; it is a valve that is not working properly, causing leakage of blood back in the wrong direction.

Inferior vena cava: The large vein which returns blood from the legs and abdomen to the heart.

Ischemia: A decrease in the supply of oxygenated blood to vital organs or body tissues due to obstruction of blood vessels.


Jugular vein: The veins that transport blood returning from the head to the heart. The veins are located on the sides of the neck and maybe swollen or distended in people with heart failure.


Left ventricular assist device (LVAD): A mechanical pump used to provide circulatory support. It helps pump blood from the left ventricle to the body. It can be used as a bridge to transplant for those awaiting a new heart, or as destination therapy to prolong life for those who are not transplant candidates.


Magnetic resonance imaging (MRI): An imaging technique that produces pictures of the heart and other body structures by using strong magnetic fields, magnetic field gradients, and radio waves to generate images.

Mitral valve: One of 4 heart valves, it controls blood flow between the heart’s left atrium and left ventricle.

Mitral valve prolapse: A condition that develops when the leaflets of the mitral valve bulge into the atrium and allow the backflow of blood.

Mitral valve regurgitation: A condition that develops when the mitral valve fails to close properly allowing blood to flow back into the upper left chamber, the left atrium, instead of flowing forward into the lower left chamber, the left ventricle.

Mitral valve stenosis: A condition that develops due to the narrowing of the mitral valve which controls the flow of blood from the heart’s left atrium to the left ventricle.

mmHg: The abbreviation for millimeters of mercury. Blood pressure is measured in units of mmHg.

Myocardial infarction: See heart attack.

Myocardium: The muscular wall of the heart.


Nuclear Medicine Imaging: An imaging technique that scans the heart after a radioactive tracer is injected into the bloodstream.


Obesity: The condition of being significantly overweight. Obesity puts a strain on the heart and can increase the risk of developing high blood pressure, diabetes, and heart failure.

Occluded artery: An artery in which the blood flow has been impaired by a blockage.

Orthopnea: Labored breathing that occurs when lying down and is generally relieved after getting up. Generally present in people with Heart Failure Classifications III or IV.


Pacemaker: An implantable device that restores the natural rhythm of the heart by sending electrical signals to cause the heart to contract. It is used to help maintain a regular heartbeat.

Palpitation: The feeling of having a fast heartbeat, fluttering or pounding heart.

Paroxysmal Nocturnal Dyspnea: Sudden shortness of breath that usually occurs during sleep. It can be caused by sleep apnea or left ventricular failure.

Percutaneous coronary intervention (PCI): Noninvasive procedures usually performed in the cardiac catheterization laboratory to open up blocked arteries.

Pericardium: The outer fibrous sac that surrounds the heart.

Plaque: Deposits of fat and cholesterol along the inner lining of blood vessel walls that increase over time, resulting in a blockage of blood flow. Plaque build-up is characteristic of atherosclerosis.

Positron emission tomography (PET): An imaging test that uses the energy of certain elements in the body to see if parts of the heart muscle are healthy and functioning.

Premature ventricular contraction (PVC): An early or extra heartbeat that happens when the heart’s lower chambers, the ventricles, contract too soon, out of sequence with the normal heartbeat.

Pulmonary artery: The artery that transports blood from the right ventricle to the lungs.

Pulmonary edema: A buildup of fluid in the lungs.

Pulmonary valve: One of 4 heart valves, it sits between the right ventricle and the pulmonary artery and controls blood flow from the heart into the lungs. It prevents blood from flowing into the right ventricle.

Pulmonary vein: A blood vessel that carries newly oxygenated blood from the lungs back to the left atrium of the heart.


Regurgitation: The backward flow of blood through a defective heart valve.

Risk factor: An attribute, characteristic or exposure of an individual that increases the likelihood of developing a disease or injury.


Septum: The muscular wall dividing a chamber on the left side of the heart from the chamber on the right.

Sinoatrial (SA) Node: The heart’s natural pacemaker, it is a group of specialized cells in the top of the right atrium which produces the electrical impulses which travel through the heart and cause it to contract.

Statins: A class of drugs that reduce cholesterol in the blood.

Stenosis: The narrowing or constriction of a blood vessel or valve leading to restricted blood flow.

Stent: An implantable “tube”, generally made of expandable metal mesh, that is placed in a narrowed or blocked artery. It is expanded and left in place to help keep the artery open so that blood may flow at a normal rate.

Subclavian arteries: Two major arteries that receive blood from the aortic arch and supply it to the arms.

Sudden Cardiac Arrest (SCA): When the heart unexpectedly and instantaneously stops working.

Superior vena cava: The large vein that transports blood from the head and arms back to the heart.

Systolic blood pressure: The top blood pressure number measures pressure in the arteries as the heart contracts with each heartbeat. Called systole, it is when the heart contracts to eject blood.


Tachycardia: An abnormally rapid heart rate or pulse greater than 100 beats per minute.

Transcatheter aortic valve implantation/replacement (TAVI/TAVR): A minimally invasive surgical procedure to repair or replace a damaged or diseased aortic valve. A balloon catheter carrying a replacement valve is inserted into an artery in the groin and threaded into the heart where it will be opened to replace the old valve and restore function.

Transplant: A major surgical procedure to replace a failing organ with a healthy one from a donor.

Tricuspid valve: One of the 4 valves which control blood flow from the right into the right ventricle. It closes the space between the right atrium and the left ventricle during a rhythmic contraction when the blood is pushed out from the chambers of the heart into the body.


Valve replacement: A surgical procedure to replace a heart valve that is either blocking normal blood flow or causing blood to leak backward into the heart. There are several surgical approaches that can be used for valve replacement.

Valvuloplasty: Opening or reshaping a heart valve with surgical or catheter techniques.

Vascular: Pertaining to the blood vessels including arteries, capillaries, and veins; which carry blood to and from the heart and help regulate blood pressure.

Vasodilators: A class of drugs which dilate (widen, expand or relax) blood vessels allowing blood to flow more freely.

Vasopressors: A class of drugs used to elevate blood pressure.

Vein: A type of blood vessel that carries oxygen-depleted blood from various parts of the body back to the heart.

Ventricle: The lower chambers of the heart, one on the left and one on the right.

Ventricular Assist Device (VAD): See LVAD.

Ventricular fibrillation: A condition in which the ventricles contract in a rapid, unsynchronized fashion. When fibrillation occurs, the ventricles cannot pump blood throughout the body.

Ventricular Tachycardia (VT): A rapid heart rate that starts in the ventricles and occurs when the heart does not have time to fill with enough blood between heartbeats to supply the entire body.


X-ray: An imaging technique that uses radiation to create a picture of internal body structures on film.

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