(HealthDay)—Autopsies show that more than 40 percent of individuals who experience sudden cardiac death (SCD) associated with coronary artery disease (CAD) have had a previously undetected myocardial infarction, according to a study published online July 10 in JAMA Cardiology.
Juha H. Vähätalo, M.D., from the University of Oulu in Finland, and colleagues compared autopsy findings, clinical characteristics, and electrocardiographic (ECG) markers associated with silent myocardial infarction (SMI) in 5,869 consecutive individuals participating in the Finnish Genetic Study of Arrhythmic Events (78.8 percent male; mean age, 64.9 years). Participants had autopsy-verified SCD between 1998 and 2017. SMI was defined as a scar detected by macroscopic and microscopic evaluation without previously diagnosed CAD. In 438 individuals, an ECG prior to SCD was available.
The researchers found that the cause of SCD was CAD in 74.8 percent of individuals, of whom 71.2 percent were not previously diagnosed with CAD. SMI was detected in 42.4 percent of individuals who experienced SCD without a clinical history of CAD, and those with SMI were more likely to be older and male. Individuals with SMI also had higher heart weight. SCD occurred more often in participants with SMI during physical activity (18.2 percent versus 12.4 percent in those without SMI). Two-thirds of those with SMI and available data (125 of 187) had a previous abnormal ECG compared with 55.4 percent of those with SCD without SMI.
“Further studies are needed to determine how to recognize and prevent SMIs to prevent SCDs,” the authors write.