Ventricular synchrony in patients with dilated cardiomyopathy and normal individuals: assessment by radionuclide ventriculography.

OBJECTIVE To establish the parameters of intra- and interventricular synchrony in normal individuals and to compare them with patients with dilated cardiomyopathy with and without conduction disorders shown in the electrocardiogram (ECG) examination. METHODS Three groups of patients were included in this study: 18 individuals (G1) with no cardiomyopathy and with a normal ECG (52+/-12 years, 29% male); 50 patients with dilated cardiomyopathy and severe left ventricular dysfunction, with 20 patients (G2) presenting QRS <120 ms (51+/-10 years, 75% male) and 30 patients (G3) with QRS >120 ms (57+/-12 years, 60% male). All patients underwent RV. Evaluation of left intraventricular dyssynchrony was carried out with the measurement of the phase histogram width and interventricular dyssynchrony was evaluated by the difference of the mean phase angle between the right and left ventricles (RLDif). RESULTS Left ventricle ejection fractions (LVEF)s were: 62 +/- 6% (G1), 27 +/- 7% (G2) and 22 +/- 8% (G3) and right ventricle ejection fractions were: 46 +/- 5% (G1), 41 +/- 6%(G2) and 38 +/- 8% (G3). Evaluation of the phase histogram width was: 89 +/- 18 ms (G1), 203 +/- 54 ms (G2) and 312 +/- 130 ms (G3), p<0.0001. The measurement of RLDif was: 14 +/- 11 ms (G1), 39 +/- 40 ms (G2) and 87 +/- 49 ms (G3); comparing G1 vs. G2 and G1 vs. G3, p<0.0001 and G2 vs. G3, p=0.0007. CONCLUSION The parameters analyzed discriminate the three groups of patients according to the ventricular synchrony degree. Patients with dilated cardiomyopathy and with no branch block in ECG (QRS <120 ms) may present dyssynchrony, but at a lower degree than patients with widened QRS.