[Phonocardiographic and two-dimensional and pulsed Doppler echocardiographic studies of Still's murmurs].

The prevalence of Still's murmur was examined by phonocardiographic study, and the clinical significance of this murmur was investigated using pharmacodynamic phonocardiography and echocardiography. Still's murmur was present in 224 of 9,478 cases (2.4%) in school children. Its prevalence was 143 in 4,524 (3.2%) in elementary school children and this was significantly greater than that in middle school youngsters who numbered 81 among 4,954 (1.6%) (p less than 0.001). There were neither abnormal findings on two-dimensional echocardiography, nor pathological regurgitant signals on pulsed Doppler examination. After the inhalation of amyl nitrite, Still's murmur was accentuated by 5.3 +/- 3.0 dB, and was louder in the expiratory than in the inspiratory phase by 4.7 +/- 3.5 dB.