Prevalence and significance of the fourth heart sound (S4) in presumably healthy middle-aged men, with particular relation to latent coronary heart disease.

As part of a cardiovascular survey phonocardiography and auscultation concentrating on the presence/absence of S4 were studied prospectively in 1714 presumably healthy men aged 40--59 yr. The following conclusions were reached: (1) routine phonocardiograms revealed an S4 in greater than 50%; (2) auscultation suggested the presence of S4 in greater than 30%; (3) interobserver variation was approximately 1/6 in the blind interprelation of the phonocardiograms by 2 observers; (4) approximately 3/4 of reported audible S4s were correctly identified; (5) a direct association between S4 and the length of the PQ (PR) interval was found, and (6) a positive association between higher blood pressure and S4, but (7) no association to age, latent coronary heart disease (CHD) nor various CHD risk factors. Thus an S4 is of little diagnostic value in screening of apparently healthy middle-aged subjects, but probably is not a completely innocent finding as suggested recently by some investigators.