Atrioventricular block secondary to straining.

Cardiac arrest while straining during a bowel movement is not unusual in elderly patients. Sinus bradycardia caused by increased vagal tone can lead to severe myocardial and cerebral hypoperfusion with cardiac arrest. We describe a female postoperative patient who, while straining on a bedside commode, developed varying degrees of atrioventricular heart block, necessitating placement of a permanent pacemaker.