Assessment of the index of left ventricular diastolic property and evaluation of left ventricular relaxation using cardiac blood pool scan

To assess left ventricular relaxation, ECG gated equilibrium blood pool study was performed in 119 patients [21 normal subjects (N), 36 angina pectoris (AP), 45 myocardial infarction (MI), 10 dilated cardiomyopathy (DCM) and 7 hypertrophic cardiomyopathy (HCM)]. The ratio of volume increment of 100 msec later than the zero point in the first derivative of the left ventricular volume curve to the end diastolic volume was expressed as early filling volume ratio (%EFV). The time constant (T) left ventricular pressure during isovolumic relaxation was measured in 65 patients by Weiss's method. The correlation between the %EFV and T was significant (Y = 33.7 ± 63.7/X, r = 0.678, p < 0.001). Compared with N (11.3 ± 1.1), the %EFV was significantly (p < 0.001) lower in AP(6.7 ± 2.1), MI(5.7 ± 1.8), HCM(5.1 ± 2.2) and DCM(4.7 ± 1.4). The peak filling rate (PFR), the filling fraction during the first third of diastole (1/3FF) and mean first third filling rate (1/3FR-m), now used as the indices of left ventricular diastolic performance, were not correlated with T. In addition, in the PFR, 1/3FF and 1/3FR-m, more 45 % of the patients with diseased heart had overlap with N. On the other hand, there were overlap only 4 % in the %EFV. Moreover, 1/3EF (r = - 0.76) and 1/3FR-m (r = - 0.535) were affected by the heart rate, but the %EFV was not influenced by the heart rate. These results indicate that the %EFV can reflect the left ventricular relaxation and is a sensitive index for evaluating the diseased heart. (author)