High Degree Atrioventricular Block Complicating Acute Myocardial Infarction Treated with Primary Percutaneous Coronary Intervention: Incidence, Predictors and Outcomes

Background: In the era of primary percutaneous coronary intervention (PPCI), information on the incidence and prognostic significance Of high degree atrioventricular block (AVB) in ST elevation myocardial infarction (STEMI) patients is limited. Objectives: To assess the incidence, time of onset, predictors and prognostic significance of high degree AVB in a large cohort of consecutive STEMI patients undergoing PPCI. Methods: We retrospectively studied 1244 consecutive STEMI patients undergoing PPCI. Patient records were reviewed for the presence of high degree AVB, its time of occurrence and relation to in-hospital complications, as well as long-termmortality over a 5 year period. Results: High degree AVB was present in 33 patients (3.0%), in 25 (76%) of whom the conduction disorder occurred prior to PPCI. Twelve patients (36%) required temporary pacing, all prior to or during coronary intervention, and all AVB resolved spontaneously before hospital discharge. AVB was associated with a significantly higher 30 day (15% vs. 2.0%, P = 0.001) and long-term mortality rate (300% vs. 6.0%, P < 0.001). Time of AVB had no effect on mortality. In a multivariate regression model, AVB emerged as an independent predictor for long-term mortality (hazard ratio 2.8, 95% confidence interval 1.20-6.44, P = 0.001). Conclusions: High degree AVB remains a significant prognostic marker in STEMI patients in the PPCI era, albeit transient.