Myocardial activity during noise exposure.

The present investigation was performed to study coronary blood flow along with other indices of cardiac activity in subjects exposed to short-term noise. The study was carried out on 10 normal-hearing individuals suffering from Variant Angina of Prinzmetal. The acoustic stimuli consisted of 100 dB (A) broad-band noise, lasting 30 s. The following parameters were examined: ECG (D1, D2 and D3) and heart-rate by means of electrocardiographic recording, left ventricular systolic pressure (LVSP), left ventricular end diastolic pressure (LVEDP) and dP/dT max by means of arterial catheterization, and coronary blood flow by means of the thermodilution method. The results, statistically evaluated by means of multiple comparison test and t-test, did not reveal any significant modifications in the ECG traces, LVEDP, or dP/dT max. The transitory and moderate variations of LVSP and heart rate were not reflected in coronary blood flow, which remained unchanged during and after noise exposure.