Temporal trends and prognostic significance of heart failure after acute myocardial infarction

Abstract Background There are limited and conflicting data regarding the incidence and prognostic impact of in-hospital heart failure (HF) complicating acute myocardial infarction (MI). The aim of this study was to examine temporal trends in the incidence and outcomes of systolic HF after acute MI in a large national cohort in South Korea. Methods The nationwide Korea Acute Myocardial Infarction Registry records baseline characteristics, treatments, and outcome of consecutive patients with acute MI admitted to hospitals capable of primary percutaneous coronary intervention (PCI) in South Korea. Systolic HF was defined as an ejection fraction ≤40% by echocardiography at admission. This study included 68,123 patients admitted for index acute MI between 2005 and 2020 (phase 1: 2005-2007, n=14,735; phase 2: 2008-2011, n=24,656; phase 3: 2012-2015, n=13,104; phase 4: 2016-2020, n=15,628). Results In all patients, the incidence of HF declined from 19.4% in phase 1 to 14.1% in phase 4 (p<0.001). This decrease was more pronounced in patients with ST-segment elevation MI (STEMI, from 20.9% to 15.8%) compared to those with non-ST-segment elevation MI (NSTEMI, from 17.9% to 12.3%). The use of PCI and of statins at discharge increased from 86% to 91.2% and from 75.1% to 92.2%, respectively (p<0.001 for all). Previous history of MI increased from 8.4% to 10.4% (p<0.001) whereas previous history of HF and stroke decreased from 6.3% to 1.3% and from 17.4% to 6.4%, respectively (p<0.001). The median symptom-to-door time decreased from 3.5 hours to 2.1 hours for STEMI and from 6.3 hours to 5.5 hours for NSTEMI (p<0.001). The median door-to-balloon time decreased from 107 min to 64 min for STEMI and from 26 hours to 14 hours for NSTEMI (p<0.001). The in-hospital and 12-month mortality rates for all patients decreased over the years from 5.0% to 3.3% and from 7.6% to 6.1%, respectively (p<0.001). However, in those who developed HF during the index MI, no significant declining trends were observed in in-hospital mortality (phase 1: 8.8%, phase 2: 7.95%, phase 3: 8.3%, phase 4: 7.3%, p=0.123) and 12-month mortality (phase 1: 15.4%, phase 2: 12.6%, phase 3: 19.4%, phase 4: 15.2%, p=0.270). Independent predictors of developing in-hospital HF were age >75 years, body mass index <18.5 kg/m2, symptom-to-door and door-to-balloon times, systolic blood pressure <100 mmHg at presentation, heart rate >90 min at presentation, presence of atrial fibrillation or diabetes, and previous history of MI, HF or stroke. Conclusions A marked reduction was found in the incidence of HF after acute MI between 2005 and 2020 in South Korea. However, in-hospital and 12-month mortality rates in HF patients remain unchanged, warranting intensive post-MI management with more aggressive efforts for secondary prevention.