Previous studies show that low frequency noise (LFN, <500 Hz, including infrasound) induces changes in the extra-cellular matrices (ECM). The pathology induced by excessive exposure to LFN is called vibroacoustic disease (VAD). The diagnostic method of choice has been echocardiography because proliferation of the ECM can be visualized in thickened cardiac structures, namely pericardium and valves. Recently echocardiograms revealed an anatomical feature that could be a consequence of Echo reveale anatomical feature echo revelased anatomical consequence of theis extra-thoracic pressure: visible hyperplasia of the eustaquian valve in the inferior vena cava. Is being observed in all patients in this currently ogoing project.
Study population: 30 selected male flight attendants, ave. age 48 (range 30-61), and 30 female flight attendants, ave. age 43 (range 27-57). Total exposure time of all individuals was > 8 yr. Echo-Doppler studies were recorded on coded videotapes. Using a 0 to 3 point scoring system, 3 morphological parameters were evaluated: thickening of the pericardium, mitral & aortic valves and vena cava’ eustachian valve.
Echocardiograms of flight attendants (males and females) disclose pericardial thickening that may appear concurrently with cardiac valve thickening, but with no consequences for diastolic mechanics. Thickened eustachian valve of the inferior vena cava were clearly visible all the study population.
At the cellular level, LFN-exposed humans and animals disclose transitory generalized fluid retention, which is maintained throughout the duration of LFN exposure (occupational or environmental). This is very discreet, decays with ceasing LFN exposure, and is not comparable to generalized common oedema, This can cause unsuspected interthoracic hypertension and can, in turn, lead to generalized extra-thoracic stasis.
Echo observation of a thicken eustaquian valve can alert for a possible VAD diagnosis.
Amilcar Araújo, None.