Echocardiographic evaluation in 485 aeronautical workers exposed to different noise environments

Introduction: Vibroacoustic disease (VAD) is a heterogeneous and systemic e ntity, caused by long term (greater than or equal to 10 yr) exposure to noi se environments characterized by large pressure amplitude and low frequency (LPALF) (greater than or equal to 90 dB SPL, less than or equal to 500 Hz) , and not explained by other possible etiologic agents. The goal of this st udy was to identify possible structural changes in hearts of men with suspe cted VAD. Methods: A total of 485 men were divided into 3 noise groups: no noise exposure (less than or equal to 70 dB), n = 48 (Group I); moderate no ise exposure, (>70dB and < 90 dB), n = 113 (Croup II); and intense noise ex posure (greater than or equal to 90 dB), n = 324 (Group III). Echo-Doppler studies were performed (HP SONGS 1500) and recorded on coded videotapes. Th ree observers performed blinded evaluations of 26 echo-Doppler parameters. For the purpose of the present study only 12 morphological parameters were compared among the groups: thickening of the mitral, aortic, tricuspid, and pulmonary valves, pericardium and endocardium: mitral valve regurgitation, prolapse and ruptured chordae tendinae; and inflow velocities. Thickness a nd severity of the applicable parameters were scored in seven-grade scale ( 0,0.5,1,...,3). Results: All evaluated parameters were statistically signif icantly different in Group I vs. Group III, except flow velocity E. Compari son of Group I vs. Group ii revealed statistically significant differences in mitral, aortic, tricuspid and pericardial thickening, with the strongest evidence for mitral and pericardial structures. Conclusions: This confirms the results of previous studies. Occupational exposure to noise environmen ts characterized by LPALF noise causes structural changes in the heart. Mit ral valve and pericardial thickening constitute the first signs of VAD.