Effect of hemodialysis on myocardial function as assessed by postural stress testing.

Myocardial performance, measured by systolic time intervals during passive postural stress, was evaluated in patients with end-stage renal disease before and after a single hemodialysis and compared with that of normal volunteers. Predialysis, the patients displayed a sluggish hemodynamic response to sudden postural changes. With tilting to 90 degrees, the patients' heart rate did not increase adequately and left ventricular ejection time (LVET) decreased only slightly in comparison to that of controls. Postdialysis, however, the response to sudden postural change in terms of increases in heart rate, decreases in LVET and decreases in calculated ejection fraction, were indistinguishable from those of control subjects. Since pre-ejection periods were not different from those of controls at any time during the test, we were unable to demonstrate a definite abnormality of myocaridal function before or after dialysis. The marked hemodynamic improvement in response to upright tilting, noted postdialysis, can be best attributed to a dialysis-related reduction in cardiac preload.