Impact of high-grade atrioventricular block on outcomes in patients with acute myocardial infarction

Abstract Aims Contemporary data on the impact of high-grade atrioventricular blocks (HAVB) in acute myocardial infarction (AMI) are scarce. Therefore, we investigated this in the Swiss national AMI registry (AMIS Plus) cohort. Methods and results We included all AMI patients enrolled from January 2005 to September 2024 with available ECG information. Primary outcome was in-hospital mortality; secondary outcomes included in-hospital major adverse cardiac or cerebrovascular events (MACCE) defined as cardiogenic shock, stroke, re-infarction or death. Among 50 279 AMI patients, 747 (1.5%) patients presented with HAVB and 407 (0.8%) developed HAVB during hospitalization. Patients presenting with HAVB had increased in-hospital mortality (15% vs. 4.9%; P < 0.001) and MACCE (17% vs. 6.0%; P < 0.001) compared with those without HAVB. High-grade atrioventricular blocks on admission was an independent predictor for in-hospital mortality (OR 1.89; 95% CI, 1.42–2.49; P < 0.001), with a stronger impact on mortality in the setting of anterior compared to non-anterior AMI (OR 3.69; 95% CI, 1.99–6.81; pinteraction = 0.02). Independent predictors for HAVB on admission included STEMI and female sex. Rates of permanent pacemaker implantation during hospitalization in patients with HAVB on admission were higher in NSTEMI than STEMI patients (20% vs. 4.4%; P < 0.001). High-grade atrioventricular blocks occurring during hospital stay was associated with higher mortality (20% vs. 15%; P = 0.031) and higher permanent pacemaker rate (25% vs. 8%; P < 0.001) than HAVB on admission. Conclusion High-grade atrioventricular blocks in AMI was associated with high in-hospital mortality, especially in anterior AMI or if occurring during hospitalization. Permanent pacemaker implantation was more frequent in the setting of NSTEMI and among patients developing HAVB during hospital stay.