Abstract 13737: Two Episodes of Intermittent Complete Heart Block Following Elective Procedures

Background: Iatrogenic bradycardia and complete heart block can occur with medications commonly administered during general anesthesia.

Case: A 79-year-old male with past medical history of coronary artery disease, hypertension, paroxysmal atrial fibrillation and a left bundle branch block, underwent elective lithotripsy procedure, baseline ECG demonstrated in Figure A. Post-operatively, he developed asymptomatic complete heart block approximately 3 minutes after receiving sugammadex, a paralytic reversal agent (see Figure B). He was admitted for monitoring and spontaneously converted to sinus rhythm after 10 hours. The patient was discharged home with a 30-day event monitor; no pauses or high-grade atrioventricular block was noted during the monitoring period. Three months later, he underwent ureteroscopy stent exchange; during the induction with propofol he developed asystole followed by cardiac arrest. CPR was initiated and had return to spontaneous circulation after 3 minutes. The patient was transferred to the ICU, however, once again complete heart block was observed.

Clinical decision-making: This case highlights recurrent episodes of transient complete heart block in the setting of an underlying left bundle branch and first-degree AV block that were exacerbated by medications during general anesthesia. Because of his underlying conduction disease and recurrent complete heart block and subsequent cardiac arrest, he ultimately underwent insertion of permanent dual chamber pacemaker.

Conclusion: Iatrogenic transient complete heart block is a rare but potentially fatal complication. Prompt diagnosis and clinical suspicion of reversible causes are warranted. Significant underlying conduction disease should be considered to decide the ideal therapeutic option.