Acute live firefighting effects on ventricular‐arterial coupling and pulsatile afterload in middle‐aged firefighters

TL;DR

Middle-aged firefighters experience cardiovascular strain during firefighting, including reduced heart efficiency and blood flow to the heart, which may increase their risk of cardiac events.

Contribution

This study examines how firefighting affects ventricular-arterial coupling and pulsatile afterload in middle-aged firefighters.

Findings

Firefighting reduced stroke volume, wasted pressure effort, aortic reservoir function, and coronary perfusion.

Ventricular-arterial coupling worsened due to increased arterial elastance.

Heart rate changes were strongly linked to changes in aortic reservoir function and wasted pressure effort.

Abstract

Firefighting increases afterload, leading to ventricular‐arterial coupling mismatch in young firefighters that may contribute to coronary hypoperfusion and the elevated risk of on‐duty cardiac events. Since this risk is higher with aging in firefighters, we examined their ventricular‐vascular coupling and afterload responses to acute firefighting. Twenty‐two male firefighters (40–59 years) performed 18‐min high‐intensity firefighting drills while wearing protective gear and breathing apparatus. Echocardiography was conducted before and within 10 min after firefighting to estimate cardiac volumes, while tonometry‐derived pulse wave analysis estimated wasted pressure effort (Ew) and aortic reservoir function. Ventricular‐arterial coupling was quantified using the arterial (Ea) to ventricular (Ees) elastance ratio, and coronary perfusion was estimated via the Buckberg index. Firefighting reduced stroke volume (difference (∆) = −17 mL, p < 0.001), Ew (∆ = −800 dyne cm−2 s, p = 0.005), aortic reservoir function (∆ = −6.9%, p < 0.001), and Buckberg index (∆ = −0.28, p < 0.001). Firefighting augmented Ea/Ees (∆ = 0.10, p = 0.035) stemming from increases in Ea (∆ = 0.16 mmHg.mL−1, p = 0.046) not counteracted by Ees. Heart rate changes were associated with Ew (r = −0.60, p = 0.017) and aortic reservoir function (r = −0.80, p < 0.001). Although middle‐aged firefighters exhibited typical post‐firefighting cardiovascular strain, including reduced coronary perfusion, the role of ventricular‐arterial interactions and pulsatile afterload remains unclear due to heart rate confounding.

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