Trends in early and late mortality in patients undergoing coronary catheterization for myocardial infarction: implications on observation periods and risk factors to determine ICD candidacy

BACKGROUND Survivors of acute myocardial infarction (MI) are at high risk for death from both sudden cardiac death and progressive heart failure. OBJECTIVE This study sought to determine mortality trends, identify markers of risk, and determine whether outcomes in high-risk patients are altered by revascularization during the implantable cardioverter-defibrillator candidacy observation period. METHODS We included 16,793 patients that presented to the catheterization laboratory for acute management of an MI. All patients had 3 years of follow-up to define short-and long-term mortality. RESULTS Across the demographics studied there were no significant differences in baseline characteristics over time, with exception of an observed decline in patients with an ejection fraction (EF) <= 0.35. Nonetheless, at study closure 16.3% of all cases had an EF <= 0.35. There was a gradual increase in use of percutaneous coronary intervention and coronary artery bypass graft; however, at the end of the study, the highest level of revascularization use was slightly >50%. For the composite, right and left bundle branch block or QRS > 120, the death rates at 1 and 5 years were 31.8% and 46.8%, respectively. These 1- and 5-year mortality rates were increased with an EF <= 0.35 (36.0%, 60.2%). Mortality in those with EF <= 0.35 exceeded 20% in all groups with conduction system disease at 90 days and was not significantly impacted by percutaneous coronary intervention. CONCLUSION The highest risk for death after MI is in patients with an EF <= 0.35 and/or conduction system disease. The mortality risk is most pronounced in the early observation period after MI when patients must wait to be considered for an implantable cardioverter-defibrillator.