• Francesco Zanon, Enrico Baracca, Gianni Pastore, Chiara Fraccaro, Loris Roncon, Silvio Aggio, Franco Noventa, Alberto Mazza, and Frits Prinzen.
• From the Arrhythmia and Electrophysiology Unit (F.Z., E.B., G.P.), Division of Cardiology (C.F., L.R., S.A.), and Department of Internal Medicine (A.M.), Santa Maria Della Misericordia Hospital, Rovigo, Italy; Department of Molecular Medicine, of Padua, Padua, Italy (F.N.); and Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands (F.P.). franc.zanon@iol.it.
• Circ Arrhythm Electrophysiol. 2014 Jun 1; 7 (3): 377-83.

BackgroundOne of the reasons for patient nonresponse to cardiac resynchronization therapy is a suboptimal left ventricular (LV) pacing site. LV electric delay (Q-LV interval) has been indicated as a prognostic parameter of cardiac resynchronization therapy response. This study evaluates the LV delay for the optimization of the LV pacing site.Methods And ResultsThirty-two consecutive patients (23 men; mean age, 71±11 years; LV ejection fraction, 30±6%; 18 with ischemic cardiomyopathy; QRS, 181±25 ms; all mean±SD) underwent cardiac resynchronization therapy device implantation. All available tributary veins of the coronary sinus were tested, and the Q-LV interval was measured at each pacing site. The hemodynamic effects of pacing at different sites were evaluated by invasive measurement of LV dP/dtmax at baseline and during pacing. Overall, 2.9±0.8 different veins and 6.4±2.3 pacing sites were tested. In 31 of 32 (96.8%) patients, the highest LV dP/dtmax coincided with the maximum Q-LV interval. Q-LV interval correlated with the increase in LV dP/dtmax in all patients at each site (AR1 ρ=0.98; P<0.001). A Q-LV value >95 ms corresponded to a >10% in LV dP/dtmax. An inverse correlation between paced QRS duration and improvement in LV dP/dtmax was seen in 24 patients (75%).ConclusionsPacing the LV at the latest activated site is highly predictive of the maximum increase in contractility, expressed as LV dP/dtmax. A positive correlation between Q-LV interval and hemodynamic improvement was found in all patients at every pacing site, a value of 95 ms corresponding to an increase in LV dP/dtmax of ≥10%.© 2014 American Heart Association, Inc.

42 keywords...

hide…