The impact of complete atrioventricular block on in-hospital and long-term mortality in patients with ST-elevation myocardial infarction

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background/aim: Complete atrioventricular (AV) block is associated with worse in-hospital outcome in patients with ST-elevation myocardial infarction (STEMI), while whether it has an impact on long-term outcome is uncertain. The majority of previous studies that analyzed this issue are performed before introduction primary percutaneous coronary intervention (pPCI). The aim of this study was to analyse the incidence and the prognostic impact of complete AV block at admission on in-hospital and 6-year mortality in STEMI patients treated with pPCI. Method we analyzed 2863 consecutive STEMI patients without cardiogenic shock at admission. Clinical, laboratory and echocardiographic characteristics and prognosis were compared between patients with and without complete AV block at admission. Results Complete AV block at admission was registered in 134 (4.6%) patients; 117 (87.3%) patients with complete AV block had inferior infarction. In comparison without complete AV block, patients with complete AV block were older; they were more likely to have heart failure, lower blood pressure and lower creatinine clearance at admission, multi-vessel disease on initial coronary angiogram and lower pre-discharge left ventricular ejection fraction (EF). Temporary pacemaker was implanted in 68 (50%) patients with complete AV block. No patient underwent permanent pacemaker implantation. In-hospital mortality was significantly higher in patients with complete AV block than in patients without complete AV block: 17.9% vs 3.6%, respectively, p < 0.001. In patients with heart block and inferior infarction in-hospital mortality was 13%,  whereas in patients with heart block and anterior infarction in-hospital mortality was 53%. When we analyze patients who were discharged alive from the hospital, we also find significantly higher long-term (6-year) mortality rate in those with complete AV block at admission vs patients without AV block: 7.8% vs 3.4% respectively, p < 0.001 (Figure 1). The causes of death in patients with complete AV block during long-term follow up were cardiovascular, e.g. sudden death, reinfarction or worsening of heart failure. In Cox regression model complete AV block was an independent predictor for in-hospital and 6-year mortality: in-hospital mortality HR 2.54 85%CI 1.93-5.22, p = 0.011; six year mortality HR 1.61, 95CI 1,09-2.37, p = 0.017. Other independent predictors for both short- and long-term mortality were age, heart failure at admission, lower creatinine clearance at admission, EF and post-procedural flow TIMI <3 thorugh infarct-related artery. Conclusion Complete AV block at admission is an independent predictor for in-hospital and long-term mortality in STEMI patients treated with primary PCI. Abstract Figure 1