ACE inhibitors
ACE inhibitors are a class of vasodilators, drugs that open ("dilate") the arteries, lowering blood pressure and therefore the heart's workload.

Anticoagulants
Anticoagulants are drugs that prevent blood clots that can block blood flow to the heart

Antioxidant
Antioxidants are nutrients and other substances that protect cells in the body from the damage caused by "oxygen free radicals" (molecules that seek to become oxidized, a process that harms body tissues and has been linked to many diseases, including stroke, heart disease, and cancer).

Arrhythmia
Arrhythmia is a general term for an irregular heartbeat, caused by problems in the heart's electrical system, which regulates heart rhythm.  A heartbeat can be too slow (bradycardia), too fast (tachycardia), or simply irregular.

Angina (also called angina pectoris)
Angina is chest pain usually caused by a lowered blood supply to the heart.

Beta-blockers
Beta-blockers are medicines that reduce the heart's tendency to beat faster.

Cardiac Ischemia
Ischemia means that a part of the body is receiving a less than adequate supply of blood and oxygen; cardiac ischemia means not enough blood and oxygen are flowing into the heart.

Cardiopulmonary resuscitation (CPR)
CPR is a series of emergency steps given to people whose hearts have stopped pumping blood (a condition known as cardiac arrest).  These steps include rescue breathing (mouth-to-mouth resuscitation) and chest compressions.  
 
Heart attack
A heart attack means the supply of blood and oxygen to the heart has been so drastically reduced that cells in the heart die; the more severe the heart attack, the more of the heart that dies.

Statins
Statins are a class of drugs that help lower cholesterol levels in the blood.

Tachycardia
Tachycardia is a type of arrhythmia (abnormal heart beat rhythm) in which the heart beats more rapidly than it should.

Thrombolytics
Thrombolytics are drugs that dissolve blood clots.