Exercise-induced ventricular arrhythmias and subclinical ischemia risk in firefighters: exploratory results from a pilot study.

Aim: This pilot study aimed to systematically evaluate exercise-induced electrocardiographic (ECG) responses in professional firefighters and to explore the association between premature ventricular complexes (PVCs) and myocardial ischemia in this high-risk occupational group.

Method: This pilot cross-sectional study enrolled 21 male firefighters (mean age 43.4 ± 7.18 years) from a single municipal fire department. Participants underwent comprehensive cardiovascular assessment including anthropometric measurements, biochemical analyses (lipid profile, testosterone), submaximal exercise testing (Bruce protocol), and 24-h Holter ECG monitoring. Statistical analyses included Mann-Whitney U tests and effect size calculations.

Results: No exercise-induced ST-segment changes indicative of myocardial ischemia were observed. However, PVCs were detected in 33% of participants (7/21), with exercise testing revealing 18 simple and 2 multiform PVCs, while Holter monitoring recorded 25 simple and 1 multiform PVC. PVC-positive firefighters were significantly older (median 49 vs. 40 years, p = 0.019, r = 0.514). Mean exercise capacity was 12.45 METs, with 81% achieving moderate fitness levels. Post-exercise heart rate recovery (HRR1: 24 ± 11.5 bpm; HRR2: 35.4 ± 11.5 bpm) showed normal patterns.

Conclusion: The findings of this pilot study indicate the need for larger-scale investigations, supported by advanced diagnostic modalities, to clarify the clinical relevance of exercise-induced premature ventricular complexes (PVCs) in firefighters. Although no ischemic changes were observed, the presence of subclinical coronary artery disease cannot be definitively excluded. These results provide a meaningful preliminary foundation for developing targeted screening approaches to improve early cardiovascular risk detection in high-physical-demand occupational groups.