Aeromedical Concerns in Asymptomatic Aviators with Left Bundle Branch Block

Left bundle branch block (LBBB) is disqualifying for aircrew in the U.S. Air Force (USAF), although outcomes for these patients is limited. We used data from the USAF School of Aerospace Medicine to study this population.

A retrospective review was performed on aircrew with LBBB identified using the Central Electrocardiographic Library database. Analysis included baseline participant demographics, cardiac risk factors, and any available cardiovascular results. Critical endpoints were coronary artery disease (CAD), cardiomyopathy (CM) (left ventricular ejection fraction of <50%) and/or clinical heart failure, and death from any cause.

At diagnosis: 271 patients met eligibility; mean age of 40.24 ± 7.39 yr. Of the 147 (54%) patients who had coronary angiography, 7 (2.6%) had aggregate stenosis 50-119% and 5 (1.8%) had aggregate stenosis ≥120%. Two patients underwent percutaneous coronary intervention, with an additional 13 (4.8%) patients demonstrating left ventricular ejection fraction of <50%; 12 were nonischemic. Longitudinal data was available for 177 (65%) patients; median follow-up was 10 yr (range 0-58 yr). During this period, 2 patients developed CAD with aggregate stenosis ≥120% and 5 had myocardial infarction. There were 37 (20%) patients who developed CM. Among 41 deaths, mean age was 75.1 ± 14.1 yr. Nine were premature (<60 yr).

Asymptomatic aviators with LBBB had elevated risk for CM (20%). Association with CAD exceeded 10% at 10 yr. Findings support current USAF policy requiring extensive cardiac evaluation and follow-up for LBBB. More prospective research is needed to validate these findings. McGregor P-C, Palileo EV, Haynes JT, Davenport ED. Aeromedical concerns in asymptomatic aviators with left bundle branch block. Aerosp Med Hum Perform. 2024; 95(12):902-907.