The bedside sphygmomanometric determination of the arterial pressure response during the Valsalva maneuver was incorporated into the routine physical examination of ambulatory subjects. Four distinct Valsalva responses were noted: ultrasinusoidal, sinusoidal, absent overshoot, and square wave. The absent overshoot response was further divided into positional and constant types--the latter consistently exhibiting this response regardless of body position. Correlation with resting left ventricular ejection fraction was obtained by radionuclide cineangiography in 200 patients, of whom 81 had left ventricular systolic dysfunction (ejection fraction less than 0.50). Significant differences in the mean left ventricular ejection fraction were found in subjects with an ultrasinusoidal response (0.65 +/- 0.11), sinusoidal response (0.55 +/- 0.15), constant absent overshoot response (0.37 +/- 0.18), and square wave response (0.16 +/- 0.04) to Valsalva maneuver. The sensitivity of an abnormal Valsalva response (absent overshoot or square wave responses) for the bedside detection of left ventricular systolic dysfunction was 69 percent, and the predictive value of an ultrasinusoidal Valsalva response for normal ejection fraction was 93 percent. It is concluded that the high predictive accuracy of the Valsalva maneuver makes this simple bedside technique a valuable method for assessing resting left ventricular function.