Basal asynchrony and resynchronization with biventricular pacing predict long-term improvement of LV function in...

Biventricular pacing (BiV) is emerging for patients with dilated cardiomyopathy (DCM) and asynchrony. We measured basal asynchrony and early resynchronization by radionuclide angioscintigraphy (RNA) in order to predict long-term evolution of ventricular function after BiV. Thirty-four patients (NYHA Class III-IV,65.4 +/- 11 years) with large QRS(179 +/- 18 ms)were implanted with BiV and studied by RNA before (D0), at day 8 (D8), and during follow-up(20 +/- 7 months). We calculated left and right ejection fractions, the interventricular dyssynchrony (TRVLV), and the apicobasal dyssynchrony (Tab). LVEF improved from 20.2 +/- 8.1%(D0) to27.1%+/- 12.6%(follow-up,P < 0.003 vs D0) and RVEF from 28.6%+/- 13%(D0) to 34.3 +/- 11.5%(follow-up,P < 0.03 vs D0). Inter- (DeltaTRVLV) and intraventricular resynchronization was immediate and remained stable: TRVLV decreased from 68.3 +/- 38 ms(D0) to 13.4 +/- 48.5 ms(D8) and1.8 +/- 39.2 ms(follow-up,P < 0.0001 vs D0); and Tab from 45.8 +/- 64.1 msto-18 +/- 68(D8) and-28.3 +/- 53.6 ms(follow-up,P < 0.0001 vs D0). Early inter- and intraventricular resynchronization (DeltaTab) at D8 were related to late LVEF and RVEF improvement. Together, an LVEF > 15% and a significant interventricular dyssynchrony (TRVLV > 60 ms) at D0 have a sensitivity of 79% and a positive predictive value of 83% to predict an improvement of LVEF superior to 5% at follow-up. In DCM patients, BiV resynchronizes ventricles early and in the long-term, while RVEF and LVEF improve progressively. Patients with large electromechanical dyssynchrony benefit most from BiV.