Cardiac arrythmias

Abstract

The American Heart Association defines cardiac arrythmias as any change from the normal sequence of electrical impulses. Cardiac arrythmias can be the result of either an abnormality of impulse formation [which can lead to impulses that are too fast, too slow or irregular] or else an abnormality in impulse conduction [which can lead to heart block]. During a normal cardiac cycle the electric impulse originates in the sino-atrial node (SA node), it then passes through the atria where it reaches the atrio-ventricular node (AV node) and is then conducted through the ventricles.