Diagnostic value of systolic time intervals in man.

The STI offer a quantitative noninvasive measure of left ventricular performance in man. Extensive studies in animals and man have validated the STI. The STI are also sensitive to changes in inotropic state, preload, and afterload, and distinction must be made between the differing effects of acute and chronic alterations upon the STI. When properly performed and interpreted the STI are useful in diagnosis (aortic valve disease, angina pectoris, and pericardial disease), evaluation of the effectiveness of cardiac compensation (coronary artery disease, mitral valve disease, hypertensive heart disease), and evaluation of surgical or pharmacologic interventions. While much investigation is required for a more comprehensive understanding of the clinical application of the STI, the studies summarized in this review support continued use of these measures for the evaluation of left ventricular performance in man.