Ventricular rhythm is irregular. Usually only a single impulse is blocked, followed by a repeat of the pattern of progressive PR lengthening and dropped beat. Atrial rhythm is usually regular. Ventricular rhythm is irregular. Ventricular rate is usually between 30 and 60 bpm.
Atrial rhythm is usually regular.
Ventricular rhythm is usually regular but may be unreliable and lead to asystole. When block occurs at AV node, QRS complex will appear normal width. When block occurs below AV node, QRS complex will be wider than 0.12 sec.