Complete atrioventricular block during anesthesia

Purpose: To describe a case of asymptomatic first degree atrioventricular b lock with a bifascicular block that progressed to complete atrioventricular block during anesthesia. This potentially fatal block was successfully tre ated with transesophageal ventricular pacing. Clinical features: A 67-yr-old man was scheduled for microvascular decompre ssion of the right trigeminal nerve under general anesthesia. His preoperat ive ECG showed first degree atrioventricular block with complete right bund le branch block and left anterior hemiblock, but he had experienced no card iovascular symptoms. Anesthesia was induced with sevoflurane 5%, and mainta ined with isoflurane 1.5-2% in oxygen. Fifteen minutes later in the left la teral decubitus position, the systolic arterial blood pressure suddenly dec reased from 80 mmHg to 0 mmHg. Then, the ECG abruptly changed from sinus rh ythm to complete atrioventricular block. The heart was unresponsive to drug therapy such as atropine 1.3 mg and isoproterenol 0.5 mg, or transcutaneou s pacing but transesophageal pacing was successful. Conclusion: Asymptomatic first degree atrioventricular block with bifascicu lar block advanced to complete atrioventricular block during anesthesia. Th e block was successfully managed with transesophageal pacing.