Predictors and in-hospital outcome of high-grade atrioventricular block in the acute phase of persistent ST-elevation myocardial infarction: Insights from the MIRAMI registry

Introduction The occurrence of high-grade atrioventricular block (HAVB) in the acute phase of STEMI is a relatively frequent complication with a major impact on the management and prognosis. Objective To determine the incidence of HAVB complicating STEMI, the characteristics of patients admitted with such a complication, their management modalities, as well as their in-hospital outcome. We also sought to identify the predictors of that complication. Method This is a retrospective study including 130 patients admitted for HAVB-STEMI. These patients were selected from the MIRAMI (MonastIR Acute Myocardial Infarction) registry that enrolled 2021 patients admitted for STEMI in the cardiology department of Fatouma Bourguiba university hospital between January 1995 and December 2019. Results The overall incidence of HAVB-STEMI was 6.4% of the MIRAMI registry population.61.53% presented with the conductive disorder on admission, and the remaining developed it during hospitalization. Patients with HAVB-STEMI were older than the rest of the population (P<0.001). Smoking (62.5%) and chronic renal failure (49.2%) were the main cardiovascular risk factors in our patients. The mean time for patient admission was 12.37hours, and only 23.6% of our patients were managed within the first 3hours. Hemodynamic complications (heart failure and cardiogenic shock) were the most frequent in our study population (P<0.001). With regard to management, 60.7% of patients received urgent reperfusion: 34.6% had primary PCI and 26.2% received thrombolysis. Temporary pacing was necessary for 51.3% of patients, and 3 patients had permanent pacemakers. Independent predictors for the occurrence of HAVB in the setting of a STEMI were: age>75years (P=0.009), chronic renal failure: (P<0.001), and occlusion of the right coronary artery: (P<0.001). In-hospital mortality was 27.7% versus 8.8% in the rest of the population. Predictors of mortality in case of HAVB-STEMI were: anemia (P=0.003), atrial fibrillation (P=0.036), ventricular fibrillation (P<0.001), heart failure (P=0.002), and mechanical ventilation (P<0.001). Conclusion Our study showed that despite the improvement in the management of STEMI, the occurrence of HAVB-STEMI is not rare and is associated with a 3-fold higher in-hospital mortality compared to the general STEMI population.