Acceleration Forces and Cardiac and Aortic Indexes in Jet Fighter Pilots

BACKGROUND: Military jet fighter pilots are exposed to acceleration (+G(z)) forces which possibly influence various cardiac parameters. Several previous studies have evaluated the impact of exposure to acceleration forces on cardiac morphology and function, but these studies were not prospective and were either based on small samples or compared jet fighter pilots with pilots of low-performance aircraft. The purpose of this study was to evaluate the effect of acceleration forces on cardiac morphologic changes in jet fighter pilots. METHODS: Routine echocardiography has been performed for jet fighter pilots since 2003. Medical records of all military jet fighter pilots who underwent echocardiography following 2003 were retrospectively evaluated. Of those, all jet fighter pilots who underwent an additional echocardiography prior to 2003 were identified. Echocardiographic parameters were recorded using M-mode and included left ventricular diameter at end systole and end diastole, interventricular septum thickness, thickness of the posterior wall, aortic root diameter and aortic valve opening, diameter of the left atrium, and left ventricular mass. Medical records of the subjects were evaluated for development of adverse events. RESULTS: There were 72 subjects who underwent 2 echocardiographic examinations with a mean follow-up period of 8.92 yr. Subjects were 18-50 yr old at the time of the initial echocardiographic examination. All parameters evaluated by M-mode were not significantly changed from the baseline examination. No adverse events occurred during the follow-up period. DISCUSSION: Findings of this study suggest that exposure to acceleration forces is not associated with cardiac and aortic morphologic changes.