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.