Ventricular fibrillation (v-fib) causes most sudden cardiac arrests (SCAs). V-fib is a type of arrhythmia. During v-fib, the ventricles (the heart's lower chambers) don't beat normally. Instead, they quiver very rapidly and irregularly. When this happens, the heart pumps little or no blood to the body.
Coronary Heart Disease (CHD) is the most common form of heart disease. It occurs when the arteries supplying blood to the heart narrow or harden from the build-up of plaque. Plaque is made up of fat, cholesterol and other substances found in the blood. This plaque build-up is also known as atherosclerosis. The site of the plaque determines the type of heart disease: 1  Coronary artery disease is the build-up of plaque in the arteries supplying blood to the heart. 2  Peripheral artery disease is the build-up of plaque in the arteries supplying blood to the arms and legs.
The types of abnormal heart rhythms. The most common types of abnormal heart rhythms are: Tachycardia. Tachycardia means that your heart is beating too fast. For example, a normal heart beats 60 to 100 times per minute in adults. Tachycardia is any resting heart rate over 100 beats per minute (BPM). There are three subtypes of tachycardia: