[An examination of left ventricular peak filling rate and ventricular relaxation rate by simultaneous acquisition of radionuclide ventriculography and left ventricular pressure].

We investigated whether peak filling rate (PFR) obtained from ECG gated radionuclide ventriculography (RNV) reflects left ventricular (LV) relaxation rate or not. Five patients with angina pectoris, 5 patients with old myocardial infarction and 6 controls were studied by simultaneous acquisition of RNV and LV pressure. RNV was performed in modified left anterior oblique position before and during angiotensin II (A II) infusion to elevate their blood pressure about 25 mmHg (A-1) and 50 mmHg (A-2). The data were acquired in a list mode and LV volume curves were reconstructed by forward and backward gating from the R wave of ECG. Actual PFR and corrected PFR by stroke volume (/SV), by end diastolic volume (/EDV), by instantaneous volume (/IV) were calculated from LV volume curve and its first differential curve. LV pressure was simultaneously measured by the catheter-tip micromanometer, and the time constant (T) of assumed exponential decline in LV pressure was calculated as index of LV relaxation rate. Although there was no correlation between actual PFR and T, corrected PFR (/EDV) and PFR (/IV) correlated with T. PFR (/EDV) decreased and T increased during A-1 and A-2. Decrease of PFR (/EDV) corresponded with increase of T. Thus, corrected PFR (/EDV) obtained from RNV reflects the rate of LV relaxation, and was considered to be an useful index to evaluate LV diastolic function.