Local electrogram delay recorded from left ventricular lead at implant predicts response to cardiac resynchronization therapy: Retrospective study with 1 year follow up

We conducted a retrospective, single–centre analysis of 161 consecutive patients with heart failure and LBBB or nonspecific intraventricular conduction delay (IVCD) treated with CRT. We routinely intend to implant the LV lead in a region with long QLV. Clinical response to CRT, left ventricular (LV) reverse remodelling (i.e. decrease in LV end-systolic diameter - LVESD ≥10%) and reduction in plasma level of NT-proBNP >30% at 12-month post-implant were the study endpoints. We analyzed association between pre-implant variables and the study endpoints.Clinical CRT response rate reached 58%, 84% and 92% in the lowest (≤105？ms), middle (106-130？ms) and the highest (>130？ms) QLV tertile (p？<？0.0001), respectively. Longer QRS duration (p？=？0.002), smaller LVESD and a non-ischemic cardiomyopathy (both p？=？0.02) were also univariately associated with positive clinical CRT response. In a multivariate analysis, QLV remained the strongest predictor of clinical CRT response (p？<？0.00001), followed by LVESD (p？=？0.01) and etiology of LV dysfunction (p？=？0.04). Comparable predictive power of QLV for LV reverse remodelling and NT-proBNP response rates was observed.LV lead position assessed by duration of the QLV interval was found the strongest independent predictor of beneficial clinical response to CRT.