Abstract Body (Do not enter title and authors here): Background: Sudden cardiac death (SCD) is a significant mode of death in both sexes, with most cases attributed to coronary artery disease (CAD). In women, ischemic SCD seems to occur more often without previously diagnosed CAD, but the prevalence and characteristics of silent myocardial infarctions (SMI) in women are not known.
Aim: This study aimed to investigate the prevalence and characteristics of women with silent myocardial infarction (SMI) and ischemic SCD.
Methods: The Fingesture study consists of 5,869 autopsy-verified SCD cases (21.1% women) in Northern Finland 1998-2017. In this study, we investigated women with ischemic SCD without previous CAD diagnosis (N=660). SMI was defined as a myocardial infarction (MI) scar at autopsy in the absence of CAD history in medical records. As a control group, we used women with ischemic SCD without MI scar and previous CAD diagnosis. Coronary artery stenosis, myocardial fibrosis, and MI scars were evaluated through macroscopic assessment during autopsy, with further histological verification for myocardial fibrosis and MI scars.
Results: Among 660 ischemic SCD subjects without prior CAD diagnosis, 220 (33.3%) had SMI. Women with SMI were older compared to those without SMI (73.4 vs. 71.4 years in subjects without SMI, p=0.03), and SMIs became more prevalent with advancing age (+4.4% per decade, p<0.01). Women with SMI had higher heart weight (411 vs. 386 g in subjects without SMI, p<0.01) and a higher prevalence of left ventricular hypertrophy (LVH) (73.6% vs. 64.5% in subjects without SMI, p=0.02). The average body mass index was 27.1 kg/m² in subjects with SMI and 27.6 kg/m² in subjects without SMI (p=0.34). Subjects with SMI were more likely to have severe coronary artery stenosis with >90% occlusion (37.3% vs. 22.5% in subjects without SMI, p<0.01). Severe (15.0% vs. 3.0% in subjects without SMI, p<0.01) and moderate (69.1% vs. 39.4% in subjects without SMI, p<0.01) degrees of myocardial fibrosis were more prominent among subjects with SMI.
Conclusions: One-third of ischemic SCD cases without prior CAD diagnosis in women had findings of SMI at autopsy. Women with SMI were slightly older and exhibited more severe coronary disease, LVH and myocardial fibrosis at autopsy. These findings underscore the importance of earlier diagnosis and treatment of CAD in SCD prevention in women.