Effect of live-fire training on ventricular-vascular coupling

Abstract

Introduction Cardiovascular events are a leading cause of firefighter duty-related death, with the greatest risk occurring during or shortly after fire suppression activity. Increased cardiovascular risk potentially manifests from detrimental changes in ventricular function, vascular load, and their interaction, described as ventricular-vascular coupling. Purpose To determine the effect of live-fire training on ventricular-vascular coupling. Methods Sixty-eight male (28 ± 7 years, 26.9 ± 3.9 kg/m 2 ) and fifteen female (36 ± 8 years, 24.3 ± 3.9 kg/m 2 ) firefighters completed hemodynamic and cardiac measures before and after 3 h of intermittent live-fire training. Left ventricular function was assessed as ejection fraction (EF) and ventricular elastance (E LV : end systolic pressure [ESP]/end systolic volume) via echocardiography and applanation tonometry-estimated ESP. Vascular load was assessed as arterial elastance (E A : ESP/ stroke volume [SV]). Ventricular-vascular coupling (VVC) was quantified as the ratio of E A to E LV and indexed to body surface area (E A I, E LV I). Results Following firefighting EF decreased (p < 0.01) with no change in E LV I (p = 0.34). SV decreased (p < 0.01) with no change in ESP (p = 0.09), driving a significant increase in E A I (p < 0.01). These changes resulted in a significant increase in the VVC ratio (p < 0.01). ConclusionThe findings suggest that firefighting does not alter ventricular elastance but increases arterial elastance in healthy firefighters, resulting in a mismatch between ventricular and vascular systems. This increase in ventricular-vascular coupling ratio and concomitant reduction in ventricular systolic function may contribute to increased cardiovascular risk following live firefighting.