[An analysis of S/N ratio of the phonocardiogram exercise test]

Phonocardiogram exercise testing (PCGET) is a method through applying a phonocardiograph to evaluate cardiac contractility and the cardiac reserve. In order to test the certainty of PCGET method, a study on its S/N ratio was performed. Thirty volunteers performed PCGET. The average value of baseline amplitudes after exercise with respect to the average value of baseline amplitudes before exercise is 1.150; The average value of number of time of the S1 amplitude after exercise with respect to the S1 amplitudes before exercise is 10.57. The results suggest that PCGET has increased S/N ratio; introcardiac noise, noise from transmission of heart/thorax acoustic system, respiratory noise, muscle noise and ambient noise could not interfere in the application of PCGET. PCGET might be a noninvasive, convenient, and inexpensive technique to quantitatively evaluate cardiac reserve for abnormal or normal persons.