Figure 2. Patterns of electrocardiographic changes during induction of cardioplegic arrest of the heart (upper part of each strip chart) and during recovery after release of the aortic cross-clamping (lower part of each strip chart). Pattern 1: Sinus rhythm to atrial fibrillation to idioventricular rhythm to sinus arrest. Recovery in reverse order. Pattern 2: Sinus rhythm to idioventricular rhythm to sinus arrest. Recovery in reverse order. Pattern 3: Sinus rhythm to atrial fibrillation to ventricular fibrillation to sinus arrest. On recovery: sinus arrest to ventricular fibrillation to electric countershock to complete atrioventricular block to atrioventricular pacing.