High risk of death among patients with high grade atrioventricular block in the setting of acute myocardial infarction, especially in the anterior region

Abstract Introduction and objectives Data arising mainly from the thrombolytic era and GRACE registry (1999–2007) suggest that high-grade atrioventricular blocks (HAVB) in acute coronary syndromes (ACS) are associated with increased in-hospital morbidity and mortality. However, contemporary data are lacking. The aim of this study is to analyze trend and outcomes of HVAB in the Swiss national registry on myocardial infarction (AMIS Plus) of nearly 20 years. Methods All acute myocardial infarction (AMI) patients enrolled in the AMIS Plus registry with available information on heart rhythm between January 2005 and September 2024 were included in the analysis and categorized into two groups based on the presence or absence of HAVB (either present on admission or detected during hospitalization). Descriptive statistics were used to categorize the groups, whereas adjusted in-hospital mortality and major adverse cardiac and cerebrovascular events (MACCE, defined as cardiogenic shock, cerebrovascular events, re-infarction and/or death) were determined by means of logistic regression analysis. The primary and secondary outcome measures of the study were in-hospital all-cause mortality and in-hospital MACCE, respectively. Results Among 50,279 AMI patients, 747 (1.5%) had HAVB and the frequency remained stable over the study period. Patients presenting with HAVB showed significantly higher in-hospital mortality (15% vs. 4.9%; p 0.001) and MACCE (17% vs. 6.0%; p 0.001) compared to those without HAVB. Moreover, HAVB at admission was an independent predictor of in-hospital mortality (OR, 1.89; 95%CI, 1.42 – 2.49; p 0.001). Among patients with HAVB, the anterior location of AMI, as compared with a non-anterior location, conferred a significantly higher mortality (p for interaction = 0.020) (Figure 1; Figure 2), while the clinical presentation related to HAVB (STEMI vs NSTEMI) has no impact on outcomes. Rates of permanent pacemaker implantation were significantly higher among NSTEMI compared to STEMI patients (20% vs. 4.4%; p 0.001). Conclusion The frequency of HAVB in the context of AMI remained relatively low and stable over the last two decades. Patients with HAVB had high in-hospital mortality, especially in the setting of anterior AMI. HAVB in the setting of NSTEMI have a lower recovery rate.Figure 1 Figure 2