Cardiac Enlargement in US Firefighters: Prevalence Estimates by Echocardiography, Cardiac Magnetic Resonance and Autopsies

Background: Cardiovascular Disease (CVD) accounts for 45% of on-duty deaths in US fire service; cardiac is common among US firefighters; and plays a major role in firefighter Sudden Cardiac Death (SCD). : To estimate the prevalence of cardiac enlargement in US Firefighters by autopsies, echocardiography (ECHO) and Cardiac Magnetic Resonance (CMR). : In the present cross-sectional study, the prevalence of Left Ventricular Hypertrophy (LVH)/ was a) estimated non-invasively among active career firefighters and b) examined by reviewing of firefighters who suffered a non-cardiac, on-duty fatality. Left ventricular mass (LVM) among active firefighters was assessed by ECHO and CMR, and normalized (indexed) for body surface area (BSA) and . Autopsy estimates were based on cardiac weights and other forensic parameters. : LVH prevalence estimates among active career firefighters presented a range from 3.3% to 32.8% ECHO; and 0.0% to 5.3% among CMR criteria. LVH was present in 17.5% and 0.4% of the active firefighters defined by LVM indexed to height 1.7 (by ECHO and CMR, respectively). LVM indexed to BSA as measured CMR indicated zero prevalence of LVH. Among non-cardiac traumatic autopsies, prevalence estimates of and LVH were 39.5% (95% CI 33.7–45.3) and 45.4% (95% CI 39.5–51.4) respectively, even after for age and BMI. : The prevalence of cardiac enlargement varied widely depending on the imaging assessment, cutoffs and the normalization techniques. For autopsy data, BMI was a major determinant of heart weight. CVD-outcome based studies are needed to provide evidence for the most accurate clinical cutoffs, while of autopsies is needed across protocols and jurisdictions.