Temporal resolution requirements for left ventricular time-activity curves.

To investigate framing rate requirements for left ventricular (LV) time-activity curves, ECG-synchronized blood pool studies of 33 patients were compared to independent techniques for evaluation of LV function. There were no significant differences in LV ejection fractions determined using different framing rates. Systolic time intervals calculated from 64- and 32-point curves were similar and correlated well with those obtained by standard methods (r = 0.81, p less than 0.001). Results from 16-point curves were worse (p less than 0.02). There were no differences between peak ejection and filling rates obtained with 64- and 32-point curves compared to angiography, but the rates calculated using 16-point curves were significantly slower (p less than 0.05). The findings suggest that LV time-activity curves acquired at 16 frames per RR interval do not provide optimum quantification of LV function indexes other than the ejection fraction.