The risk of cardiac complications in surgical patients with bifascicular block. A clinical and electrophysiologic study in 98 patients.

Ninety-eight patients with ECG evidence of bifascicular block who had undergone general anesthesia and surgery have been followed up. His bundle electrogram was recorded in all patients prior to the surgery. On the basis of electrophysiologic studies, patients were classified in two groups: normal H-V group (47 patients) and prolonged H-V group (51 patients). The prolonged H-V group presented a significantly greater incidence of organic heart disease and cardiac symptoms. Correspondingly, there was a significantly higher incidence of cardiac intra- and postoperative complications in patients with prolonged H-V interval, but none of the patients developed complete heart block. Ventricular fibrillation and not the occurrence of complete heart block, was the cause of sudden cardiac death in three patients who had a prolonged H-V interval and severe organic heart disease. Patients with bifascicular block, undergoing anesthesia and surgery, even in the presence of presumable risk factors, do not require prophylactic pacing. The H-V duration represents a more accurate predictor of major cardiac intra- and postoperative complications than the surface recordings, but only in patients with symptomatic heart disease. These data support the concept that high-risk patients can be identified clinically and thus preoperative determinations of H-V intervals should not be recommended.