Clinical use of pressure-dimension and stress-shortening relations in systole and diastole.

The concept of time-varying elastance is an important one and has clinical relevance for both systole and diastole. The application of this concept to systole has permitted the development of end-systolic pressure-volume (dimension) and stress-shortening analysis as a method of assessing myocardial contractility in patients at risk for congestive cardiomyopathy. The application of the time-varying elastance concept to diastole is particularly relevant to new findings concerning abnormal relaxation in hypertrophic cardiomyopathy and angina pectoris.