The electrical heart<unk>  is an average of all electrical depolarization in the heart. The depolarization wave begins in the right atrium and proceeds toward the left and right ventricle. Because the left ventricle wall is thicker than the right wall, the arrow indicating the direction of the depolarization wave is directed toward the left.
QRS axis and voltage
Pulseless electrical activity classification
Bradycardia classification
TIMI myocardial perfusion grade
Atrial flutter classification
AVNRT classification
TIMI thrombus grade
TIMI flow grade