Left ventricular filling in dilated cardiomyopathy: Relation to functional class and memodynamics

Left ventricular systolic function does not correlate well with functional class in patients with dilated cardiomyopathy. To determine whether the correlation is better with Doppler indexes of left ventricular diastolic function, 34 patients with dilated cardiomyopathy (M-mode echocardio-graphic end-diastolic dimension >60 mm, fractional shortening <25%, increased E point-septal separation) were studied. Patients were classified into two groups according to functional class. Group 1 consisted of 16 patients in New York Heart Association functional class I or II; group 2 included 18 patients in functional class III or IV. Left ventricular dimensions, fractional shortening, left ventricular mass, meridional end-systolic wall stress, peak early and late transmitral filling velocities and their ratio, isovolumetric relaxation period and time to peak filling rate were computed from pulsed wave Doppler and M-mode echocardiograms and calibrated carotid pulse tracings. Right heart catheterization was performed in 20 of 34 patients.No differences were observed between groups with regard to age, gender distribution, heart rate, blood pressure and M-mode echocardiographic-derived indexes of systolic function. Peak early filling velocity (72 ± 13 versus 40 ± 10 cm/s, p < 0.001) was higher and atrial filling fraction (27 ± 4% versus 46 ± 8%, p < 0.001) was lower in group 2 than in group 1. The ratio of early to late transmitral filling velocities was higher in group 2 patients (2.3 ± 0.5 versus 0.7 ± 0.2, p < 0.001). The duration of the isovolumetric relaxation period (53 ± 16 versus 85 ± 14 ms, p < 0.001) and the time to peak filling rate (121 ± 24 versus 154 ± 17 ms, p < 0.01) were significantly shorter in group 2.All these differences occurred at a time when mean pulmonary capillary wedge pressure (31 ± 10 versus 11 ± 5 mm Hg, p < 0.01) was higher, stroke index was lower (23 ± 10 versus 12 ± 4 ml/beat per m2, p < 0.001) and the grade of mitral regurgitation (2.4 ± 0.4 versus 1.1 ± 0.2, p < 0.001) was larger in group 2 patients.Peak early transmitral filling velocities correlated significantly with mean pulmonary capillary wedge pressure (r = 0.86, n = 20) and the magnitude of mitral regurgitation (r = 0.74, n = 34) and inversely with stroke index (r = −0.61, n = 20). A strong correlation (r = 0.81) was also observed between mean pulmonary capillary wedge pressure and magnitude of mitral regurgitation.Thus, in patients with dilated cardiomyopathy, diastolic transmitral filling of the left ventricle is determined by left atrial pressure and the severity of mitral regurgitation. Moreover, it correlates better with functional class than do indexes of left ventricular systolic function