Abnormalities in the Cardiac Cycle

The heart is evolutionary masterpiece. Yet like everything else in nature, it is not perfect and problems may arise. However before its flaws can be mentioned and analysed. It would be prudent to understand how the heart functions in the first place before going in depth into the various problems that might arise within the cardiac cycle. Of which a large number are covered under the various Arrhythmias, which can be divided into two major groups, ventricular arrythythmias and supraventricular arrythythmias. I.e., arrythythmias that occur in the ventricles and arrythythmias that occur above them. Subdivision is possible, with arrhythmias further divided into Disorders of impulse conduction and disorders of impulse generation.
The various and detailed events that take place with every heart beat is referred to as the "cardiac cycle". The top chambers of the heart are called the atria and the bottom chambers, the ventricles. A normal heart beat begins when the Sino-Atrial Node, located on the posterior wall of the right atrium. The Sino-Atrial Node initiates the "wave of contraction" which results in the contraction of the atria. The Atrio-Ventricular Node delays the signal initiates by the Sino-Atrial node for about 0.15 seconds, permitting full atrial systole before ventricular systole. …