Pacemaker dependence in patients with bifascicular block during acute anterior myocardial infarction

Pharmacological stress testing of the His-Purkinje system in patients with bifascicular block

This literature review, based mainly on the English-language literature, focuses on pharmacological stress testing of the His-Purkinje system as part of an invasive electrophysiological study. The main target group for this investigation is patients with bifascicular block and syncope in which intermittent high grade AV block is suspected. Several drugs have been used for this purpose, mainly Class I antiarrhythmic agents such as ajmaline, procainamide, disopyramide, and flecainide. Most studies, unfortunately, suffer from limited patient numbers, lack of adequate control groups, and/or adequate follow-up. The sensitivity of the disopyramide stress test has been shown to be 75%-100% for prediction of impending high grade AV block. The specificity was > 90%. Studies on procainamide have shown a sensitivity of 60% but the specificity has not been assessed. There are no studies allowing a strict comparison of the diagnostic value of pharmacological provocation with different drugs. Based on the similarities of the electrophysiological effects on the His-Purkinje system of the above Class I agents, it is reasonable to assume that all of them might be of diagnostic value in the present clinical context, provided atrial and ventricular stimulation after drug is included in the protocol.

The role of permanent pacing after anterior myocardial infarction complicated by transient complete atrioventricular block

A randomised study was performed to assess the influence of prophylactic permanent pacing on the incidence of late sudden death in patients surviving transient complete atrioventricular block with acute anterior myocardial infarction. Fourteen patients were studied, of whom ten died within two years, confirming the high overall late mortality in this group. The deaths included eight of the nine paced patients, of whom seven died suddenly. We conclude that prophylactic permanent pacing is not warranted in patients surviving transient complete atrioventricular block with acute anterior myocardial infarction.