For those not familiar with medical terminology related to cardiac conditions, here's an alphabetical list of such terms, courtesy of Philips:
Arrhythmia: Abnormal electrical activity of the heart resulting in an irregular, intermittent, or absent pulse.
Biphasic waveform: A pattern of electrical flow where the direction of the current is reversed midway through the pulse. A biphasic waveform requires less energy than a monophasic waveform to achieve comparable defibrillation efficacy.
Cardiopulmonary resuscitation (CPR): A technique employed to briefly keep oxygenated blood flowing to vital organs until definitive intervention can be instituted. Steps include emergency notification, mouth-to-mouth or mask ventilation, and external chest compression.
Defibrillation: The treatment of irregular, intermittent, or absent heart rhythms by delivering electrical current to the heart.
Defibrillator: A device that can deliver an electrical current to the heart to treat arrhythmias. Many are portable devices and have electrocardiographic monitoring capability. There are two types of defibrillators, automated external defibrillators (AEDs) and manual defibrillators. The former are portable devices that contain sophisticated electronics to monitor and identify the cardiac rhythm. They only permit the operator to deliver the shock if ventricular fibrillation is occurring. The latter require the operator to read and interpret the ECG tracing and may require specific steps to program and administer the electric shock.
Electrocardiogram (EKG/ECG): A graphical representation of electrical impulses produced by the heart.
Heart attack: Death of heart tissue due to a blocked artery, which may lead to sudden cardiac arrest (SCA).
Implantable cardioverter defibrillator (ICD): A small surgically implanted defibrillator, weighing less than 4 oz., that senses abnormal heart rhythms, and within seconds of detection delivers an electric jolt to the heart.
Monophasic waveform: A pattern of electrical flow where the current, throughout the pulse, flows in one direction, from one electrode pad, through the body, to the other electrode pad.
Public access defibrillation (PAD): The widespread employment of defibrillators in public areas intended to make them more readily available for responding to sudden cardiac arrest.
Sudden cardiac arrest (SCA): Precipitous loss of effective pulse and blood pressure usually due to cardiac arrhythmia, primarily ventricular fibrillation.
Sudden cardiac death (SCD): Death occurring within one hour of an acute cardiac event.
Ventricular fibrillation: A chaotic arrhythmia that causes the heart to quiver instead of contract in a coordinated manner. No effective blood pressure is generated, unconsciousness is immediate, and death follows within minutes if arrhythmia is not halted.
Ventricular tachycardia: A condition in which an area of the ventricle heart muscle develops pacemaker activity, resulting in a very fast, abnormal heartbeat, often leading to sudden cardiac arrest.