Investigation of Myocardial Substrate for Sudden Arrhythmic Death in Coronary Artery Disease Without Acute Coronary Thrombosis or Myocardial Infarction.

Abstract

Background: This cohort study aimed to evaluate the potential myocardial arrhythmic substrate in people with coronary artery disease who died from sudden arrhythmic death (SAD) without acute coronary thrombosis or myocardial infarction.

Methods and results: We performed histological analysis of the left ventricular free wall obtained at autopsy from decedents with ≥1 coronary artery and ≥75% area stenosis who died suddenly from either noncardiac causes (25 men, 23 women) or SAD (25 men, 25 women), matched for age and sex. Decedents with acute coronary thrombosis, myocardial infarction, or other myocardial abnormality were excluded. Decedents with either noncardiac death or SAD had similar height, weight, and heart weight. Decedents with SAD had higher cumulative area stenosis of coronary arteries (mean, 162% versus 134%; mean difference, 29% [95% CI, 1%-56%], P=0.042) and a higher proportion of decedents with SAD had diabetes (mean, 10% versus 0%; mean difference, 10% [95% CI, 2%-18%], P=0.025) and chronic, nonocclusive, organized coronary artery thrombus (mean, 16% versus 0%; mean difference, 16% [95% CI, 6%-26%], P=0.0040). Moreover, decedents with SAD had lower cardiomyocyte width (mean, 18.6 μm versus 19.6 μm; mean difference, 1.0 μm [95% CI, 0.2-1.8], P=0.014) and higher capillary length density (mean, 3618 mm/mm³ versus 3164 mm/mm³; mean difference, 453 mm/mm³ [95% CI, 210-697], P=0.0003) than decedents with noncardiac death.

Conclusions: SAD in people with coronary artery disease without acute coronary thrombosis or myocardial infarction was associated with greater coronary artery plaque burden and cardiomyocyte atrophy that may have contributed to myocardial substrate for arrhythmia.