Temporal discrepancies between low and high frequency vibrations of the second heart sound

The morphologic analysis of the second heart sound may provide some useful informations, not enough debated in the literature, concerning the functional status of cardiac patients. We noticed significant temporal discrepancies on the phonocardiographic tracings between the onset of the second heart sound in the lowest and in the highest frequency ranges. The correlations between the highest and the lowest frequency vibrations of the second heart sound were analysed in 119 controls, without overt cardiovascular disease, aged from 20 to 40 years and 50 to 70 years and in 148 patients with old myocardial infarction aged 42 to 80 years. The lowest frequency vibrations of the second heart sound appeared earlier in healthy young subjects than in middle-aged people. These differences may be explained by the reduced aortic compliance with advanced age. The incidence of early beginning of the low frequency vibrations of the second heart sound is greater in patients with old myocardial infarction and a poor myocardial contractile condition than in controls of about the same age. This difference may be due to impaired ventricular relaxation.