context: Ablation: Removing or destroying tissue. Cardiac ablation can treat atrial fibrillation, a type of irregular heart rhythm that sometimes leads to heart failure. Aneurysm: A sac formed by a bulging blood vessel wall or heart tissue. If it gets too large, it can rupture. The bleeding can be life-threatening. Large aneurysms should be treated. Angina (also called angina pectoris): Discomfort or pressure, usually in the chest. It's a temporary feeling that happens when your heart muscle doesn't get enough blood. You may also feel pain in your neck, jaw, or arms. Angioplasty/balloon angioplasty: A blocked artery treatment. The doctor places a special balloon catheter where the artery narrows, then inflates it to help increase blood flow to your heart. He'll probably place a device called a stent in there to help keep the artery open. Angiotensin-converting enzyme inhibitors ( ACE inhibitors): Drugs used to treat high blood pressure and heart failure. Angiotensin receptor neprilysin inhibitors ( ARNIs): Drugs used to treat heart failure. They ease the strain on the heart muscle. Angiotensin II receptor blockers ( ARBs): A group of drugs used to treat high blood pressure and heart failure. Aortic insufficiency: Also known as aortic valve regurgitation, it's when blood leaks through the valve and into your heart. Small leaks aren't always a problems, but big ones require repairing or replacing the valve. Aortic valve homograft: When your doctor uses a human valve to replace your narrow or leaky aortic valve. This operation involves cardiopulmonary bypass. Aortic valve repair: When the aortic valve is leaking or too tight, a surgeon may be able to repair the valve rather than replace it. Aortic valve replacement: A diseased aortic valve can become either too narrow or leaky. In those cases, the doctor will replace it. Atherectomy (directional coronary atherectomy, or DCA): A procedure used to clean out clogged arteries. The doctor inserts a catheter with a balloon on one end into a narrowed artery. The balloon is inflated to unclog the artery. A blade inside the catheter rotates to shave off any plaque. The shavings are caught inside the catheter and removed. Atherosclerosis ("hardening of the arteries"): Plaque builds up inside your arteries and can lead to coronary artery disease and other problems. Atrial fibrillation ( AF or AFib): An irregular heart rhythm. The upper chambers (atria) of the heart quiver and don't empty into the lower chambers (ventricles) completely. Atrial flutter: A heart rhythm that's too fast and causes the upper chambers (atria) to beat too fast and not in sync with the lower chambers (ventricles). Beta-blocker: A drug that slows heart rate, lowers blood pressure, and controls angina. It protects you from future heart attacks if you've already had one. Cardiac arrest: When your heart's electrical system malfunctions and it stops beating. It's not the same thing as a heart attack. Cardiomyopathy: A serious condition in which your heart doesn't pump as well as it should and becomes weak. It can lead to heart failure and valve problems. There are many types. The most common results from coronary artery disease. Cardioversion: A procedure used to return an irregular heart rhythm to normal through an electric shock or drugs. It can be used in emergencies. Carotid artery disease: A progressive disease that involves the buildup of plaque in your carotid arteries. It can lead to a stroke. Commissurotomy: A surgical procedure that helps open blocked or defective heart valves. Congestive heart failure ( CHF or heart failure): A chronic condition in which your heart muscle weakens and can't pump enough blood through your body. Coronary artery bypass graft: If your coronary artery disease results from heart failure, a doctor can take arteries or veins (called grafts) from other parts of your body to reroute blood flow around blocked heart arteries. Coronary artery disease (atherosclerosis): A buildup of fatty material in the wall of the coronary artery that causes it to narrow. It can lead to heart failure. Defibrillator: A machine that gives your heart an electric shock to re-establish a normal heart rhythm. It's used in cardiac arrest. ECMO (extracorporeal membrane oxygenation): If you can't provide oxygen for your own blood or enough blood circulation, you can be put on life support known as extracorporeal membrane oxygenation. The doctor withdraws blood from a large vein in and passes through a device that puts oxygen into it and takes carbon dioxide out before it goes back into your body. Endocarditis: An infection of the inner lining of the heart or its valves. It's usually caused by bacteria and is more likely to occur in if you have heart valve defects or have had heart surgery to treat valve disease. Enhanced external counterpulsation ( EECP): A treatment for people who have coronary artery disease but can't have standard treatments like bypass surgery. The doctor wraps special cuffs around your calves, thighs, and buttocks. They're inflated and deflated. This narrows the blood vessels in your lower limbs and boosts blood flow to your heart. Fibrillation: Rapid, inefficient contractions of your heart. Heart attack (myocardial infarction): Permanent damage to your heart muscle. It happens when a blocked artery leads to a lack of blood supply. Heart block: When your heart can't beat the way it should because electrical signals between the atria and ventricles are out of whack. Severe cases may require a pacemaker. Heart failure (congestive heart failure, or CHF): When your heart muscle is too weak to pump enough blood to your body. Fluid builds up in your lungs, hands, ankles, and other body parts. Heart-lung bypass machine: It puts oxygen into your blood and helps it move through your body during open-heart surgery. Immunosuppressants: Drugs that keep your body's immune system from rejecting a transplanted organ, like a heart. Implantable cardioverter defibrillator ( ICD): An implant that monitors your heart rate and rhythm. When it finds a very fast, abnormal rhythm, it gives the heart muscle an electrical shock so it can beat in a normal rhythm again. Inotropic medication: A drug used to strengthen your heart's contractions and improve blood circulation. Intra-aortic balloon pump assist device ( IABP): A device that helps your heart pump. Your doctor inserts a balloon through an artery at the top of your leg, and it goes into your chest. It inflates and deflates to help your heart move blood in and out. Ischemia: When you don't get enough oxygen-rich blood to an organ to keep it healthy. When it happens to your heart, it can cause chest pain. Left ventricular assist device ( LVAD): A device used to help your heart work when you have end-stage heart failure. Mechanical valve: It replaces a diseased heart valve. If you get one, you'll take blood thinners to prevent blood clots. Minimally invasive heart surgery: In this technique, your doctor makes small cuts on the side of your chest, rather than in the middle. It leaves your breastbone intact, so you may heal and recover quicker. Mitral stenosis: When your mitral valve narrows and prevents the easy flow of blood. Multigated acquisition scan ( MUGA scan): A test used to tell how well your heart pumps. Myocardial biopsy (cardiac biopsy): When your doctor cuts out a tiny piece of heart muscle tissue for analysis. Myocardial infarction (heart attack): See heart attack (above). Myocarditis: Inflammation of the myocardium (heart muscle). Pacemaker: A small electronic device implanted under your skin. It sends electrical impulses to the heart muscle to regulate your heart rhythm. Pulmonary hypertension: High blood pressure in your pulmonary arteries. Restenosis: Closing or narrowing of an artery that was previously opened with a procedure like angioplasty. Stent: A small tube your doctor puts in during an angioplasty to keep the coronary artery open for blood flow. Permanent stents are made of metal mesh, while others are designed to dissolve. Stroke: A sudden loss of brain function caused by less blood flow to part of your brain. Causes include blood clots in the brain and bleeding into the brain. Transient ischemic attack ( TIA): A stroke-like event that can last minutes or hours. It happens when your brain can't get oxygen-rich blood. The effects wear off, usually with no permanent damage, after blood flow resumes. It can be a warning sign of stroke. Unstable angina: It causes unexpected chest pain, usually while you're at rest. Drugs can help, but because it's unstable, it could progress to a heart attack. Valvuloplasty: This procedure improves valve function by reshaping the heart valve. Vasodilator: A type of drug that relaxes and dilates blood vessels, allowing more blood flow. Ventricular fibrillation: An erratic, disorganized firing of impulses from the ventricles, so they're unable to contract or pump blood to the body. This is a medical emergency that must be treated with CPR and defibrillation. Ventricular tachycardia: A rapid, life-threatening rhythm that starts in the heart's lower chambers. It prevents your heart from filling with blood, and less blood is able to pump through the body.