The criteria to diagnose a<unk>  on the electrocardiogram: * The heart rhythm must originate above the ventricles (i.e., sinoatrial node, atria or atrioventricular node) to activate the conduction system at the correct point. * The QRS duration must be more than 100 ms (incomplete block) or more than 120 ms (complete block). * There should be a terminal R wave in lead V1 (often called "R prime," and denoted by R, rR', rsR', rSR', or qR). * There must be a prolonged S wave in leads I and V6 (sometimes referred to as a "slurred" S wave). The T wave should be deflected opposite the terminal deflection of the QRS complex. This is known as appropriate T wave discordance with<unk>  branch block. A concordant T wave may suggest ischemia or myocardial infarction.
Right bundle branch block
Left bundle branch block
Bundle branch block
Sinoatrial block
Pre-excitation syndrome
Atrioventricular block
Sinoatrial arrest
Torsades de pointes