Role of intraoperative electrical parameters in predicting reverse remodelling after cardiac resynchronization therapy and correlation with interventricular mechanical dyssynchrony

Cardiac resynchronization therapy (CRT) was shown to reverse left ventricular (LV) remodelling in heart failure (HF) patients. We aimed to investigate whether intraoperative electrical parameters (IEP) were predictive factors of LV reverse remodelling and were correlated with mechanical dyssynchrony indexes. Eighty-six patients with HF underwent CRT. At implant, several electrical and echocardiographic parameters were evaluated and, at 6 months, responders were defined by a relative increase in LV ejection fraction >= 25% compared with baseline. Several IEPs were shown to predict LV reverse remodelling. Receiver operating curve analysis revealed the ratio between QRS duration during biventricular pacing (BVp) and right ventricular pacing (RVp) [QRS(BVp)/QRS(RVp)] as the best predictor of LV functional recovery after CRT (AUC = 0.72; 95% confidence limit 0.57-0.82; P < 0.001). Responders showed a lower value of QRS(BVp)/QRS(RVp) when compared with non-responders (0.74 +/- 0.05 vs. 0.8 +/- 0.1; P < 0.005) and 0.78 was the value associated with the best predictive accuracy. The interval between the onset of RV lead and LV lead electrograms (RVegm-LVegm) during baseline rhythm correlated directly with the interventricular mechanical delay (IVMD) (r = 0.68; P < 0.0001) and with its reduction (delta IVMD) at follow-up (r = 0.66; P < 0.0005). Intraoperative electrical parameters can predict LV functional recovery after CRT and they are correlated with interventricular mechanical resynchronization at follow-up.