Prevalence and Aeromedical Implications of Cardiac Conduction Abnormalities in Korean Air Force Pilots: A Cross-Sectional Study

Purpose: Cardiac conduction abnormalities detected on electrocardiography are often asymptomatic and considered benign.However, in aviation medicine, they required careful evaluation because of the potential risk of sudden in-flight incapacitation.Data on their clinical significance among military aircrew are limited.Methods: We conducted a retrospective study of 2,827 Korean Air Force aircrew who underwent checkup between 2021 and 2022.Conduction abnormalities-including complete right bundle branch block, left anterior fascicular block, left posterior fascicular block, and bifascicular block-were identified on 12-lead electrocardiography.Clinical, metabolic, echocardiographic, and exercise test data were analyzed.Logistic regression assessed factors associated with conduction abnormalities.Results: Conduction abnormality was identified in 27 participants (1.0%), with left anterior fascicular block being the most common (0.5%).Participants with conduction abnormalities demonstrated normal findings on echocardiography and treadmill test.Complete separation was observed between conduction abnormalities and echocardiographic abnormalities.In univariate analysis, metabolic syndrome was associated with the presence of conduction abnormalities (odds ratio [OR] 2.53, 95% confidence interval [CI] 1.01-6.32),while age, smoking, and other metabolic parameters were not.In multivariable analysis adjusting for age, the association with metabolic syndrome remained of borderline statistical significance (adjusted OR 2.50, 95% CI 0.98-6.35).Conclusion: Among military aircrew undergoing checkup, cardiac conduction abnormalities were uncommon and were not accompanied by structural or exerciseinduced cardiac abnormalities.These findings indicate that isolated, asymptomatic conduction abnormalities may occur without detectable structural heart disease in this highly selected population.Further longitudinal studies are required to clarify their long-term clinical and aeromedical significance.