[A fourth tone and latent cardiac insufficiency in ischemic heart disease].

An assessment was made of the fourth heart sound as a non-invasive clinical and instrumental aid in the diagnosis of latent cardiac insufficiency. The sound was recorded in various decubitus positions in a series of healthy subjects and patients with recent and past infarction, under basal conditions, after exercise on the cycle ergometer, and after digitalis i.v. Persistence of the fourth sound in the standing position was noted in nearly all infarct patients, while its incidence decreased significantly after digitalis. It is felt that this finding can be interpreted as evidence of the non-existence of latent heart failure. Its further investigation and correlation with other invasive and non-invasive instrumental examinations is proposed.