Assessment of left ventricular pressure-volume relations using gated radionuclide angiography, echocardiography, and micromanometer pressure recordings. A new method for serial measurements of systolic and diastolic function in man.

This study was designed to validate the use of combined invasive and noninvasive methods in assessing serial pressure-volume relations in man. Ten patients undergoing cardiac catheterization were studied with simultaneous intracardiac micromanometer pressure recordings, gated radionuclide angiography and echocardiography. Systolic and diastolic function were measured at rest, during right atrial pacing rates of 100 and 120 beats/min and after nitroglycerin administration. Right atrial pacing studies (rate of 100 beats/min) were performed in duplicate to determine the reproducibility of the method. At the conclusion of each study, the model was validated with contrast angiography. Good reproducibility was evident when measuring the maximum and average filling and ejection rates, time to peak filling rate, ejection fraction, the modulus of chamber stiffness, the time course of left ventricular relaxation, global average stress and ventricular work indexes using the model described above. These data were not significantly different (p greater than 0.05) from comparable data obtained from contrast angiography. Right atrial pacing and nitroglycerin administration resulted in predictable alterations in the pressure-volume loop and in the systolic and diastolic measurements. The maximum and average filling rates, ejection rates and time to peak filling rate appeared to be heart rate-dependent variables. By combining available invasive and noninvasive methods, accurate pressure-volume relationships can be determined. Because the method we tested provides accurate volumetric and timing measurements for cardiac events and does not alter hemodynamics, it may be useful for obtaining serial assessments of the pressure-volume relationship in man.