Incidence, temporal trends, and prognostic impact of heart failure complicating acute myocardial infarction. The SWEDEHEART Registry (Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies): a study of 199,851 patients admitted with index acute myocardial infarctions, 1996 to 2008

Abstract

Objectives: The aim of this study was to examine temporal trends in the incidence and outcomes of heart failure (HF) complicating acute myocardial infarction (AMI) in a large national cohort.

Background: There are limited and conflicting data concerning temporal trends in the incidence and prognostic implication of in-hospital HF that complicates AMI.

Methods: The nationwide coronary care unit registry SWEDEHEART (Swedish Web-System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies) records baseline characteristics, treatments, and outcome of consecutive patients with AMIs admitted to all hospitals in Sweden. The diagnosis of HF requires the presence of crackles (Killip class ≥II) or the use of intravenous diuretic agents or intravenous inotropes. This study included 199,851 patients admitted for index AMIs between 1996 and 2008.

Results: The incidence of HF declined from 46% to 28% (p < 0.001). This decrease was more pronounced in patients with ST-segment elevation myocardial infarctions and left bundle branch block (from 50% to 28%) compared with those with non-ST-segment elevation myocardial infarctions (from 42% to 28%) (p < 0.001). The in-hospital, 30-day, and 1-year mortality rates for patients who developed HF during the index myocardial infarction decreased over the years from 19% to 13%, from 23% to 17%, and from 36% to 31%, respectively (p < 0.001 for all). Thirteen-year survival analysis showed higher mortality in patients with HF compared with those without HF (adjusted hazard ratio: 2.1; 95% confidence interval: 2.06 to 2.13).

Conclusions: A marked decrease was found in the incidence of HF complicating AMI between 1996 and 2008. However, HF continues to worsen the early-, intermediate-, and long-term adverse prognostic risk after AMI.

Keywords: epidemiology; heart failure; myocardial infarction; prognosis.