[A phonomecanographic test of hyperthyroidism].

Systolic intervals may be studied by phonomechanography. This provides data regarding the function of the left ventricle. In the absence of any problem of intraventricular conduction or valvular lesion, such information is particularly valuable. Thyroxine impregnation, whetHer active directly and/or by catecholamine hypersecretion, results in cardiac hyperkinesia which is reflected not only by tachycardia but also a shortening penetration time and contraction of the ventricular muscle. This shows itself within systole as a change in the relation between the duration of the pre-ejection phase (PPE) and the ejection phase. The first decreases whilst the second remains normal and their ratio changes, PPE/E changes from a normal value of 0.34 +/- 0.04 to 0.25 +/- 0.03. These tests are not only of value in diagnosis but also make it possible to observe the effects of treatment. It is certain that a true phonomechanographic syndrome of cardiac hyperkinesia may be described. The commonest, though not the only, aetiology is hyperthyroidism.