title: Incremental prognostic value of combining left ventricular lead position and systolic dyssynchrony in predicting long-term survival after cardiac resynchronization therapy.
abstract: The efficacy of CRT (cardiac resynchronization therapy) can be affected by a number of factors; however, the prognostic significance of the LV (left ventricular) lead position has not been explored. The aim of the present study was to examine whether a PL (posterolateral) lead position has an additional value to systolic dyssynchrony in predicting a better survival after CRT. Patients (n=134) who received CRT were followed-up for 39+/-24 months. The LV lead position was determined by cine fluoroscopy, and baseline dyssynchrony was assessed by TDI (tissue Doppler imaging). The relationship between the LV lead position/dyssynchrony and mortality was compared using Kaplan-Meier curves, followed by Cox regression analysis. The all-cause and cardiovascular mortalities were 38 and 31% respectively. The presence of dyssynchrony and a PL lead position predicted a lower all-cause mortality (29 compared with 47%; log-rank chi2=5.38, P=0.02) and cardiovascular mortality (21 compared with 41%; log-rank chi2=6.75, P=0.009) than when absent. The all-cause mortality was as high as 62% when patients had neither dyssynchrony nor a PL lead position, but was reduced to 29% when both criteria were present, and was between 45 and 46% when only one criterion was present (chi2=6.79, P=0.01). The corresponding values for cardiovascular mortality were 62% when patients had neither dyssynchrony nor a PL lead position, 36-38% when patients had either dyssynchrony or a PL lead position, and 21% when patients had both criteria present (chi2=9.54, P=0.004). Combining dyssynchrony and a PL lead position independently predicted a lower all-cause morality {HR (hazard ratio), 0.496 [95% CI (confidence interval), 0.278-0.888]; P=0.018} and cardiovascular mortality [HR, 0.442 (95% CI, 0.232-0.844); P=0.013]. In conclusion, the placement of the LV lead at a PL position provides additional value to baseline dyssynchrony in predicting a lower all-cause and cardiovascular mortality during long-term follow-up after CRT.
authors.affiliation: Li Ka Shing Institute of Health and Sciences, Institute of Vascular Medicine, Division of Cardiology, Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhang
authors.forename: Gabriel W-K
authors.initials: GW
authors.lastname: Yip
authors.forename: Yat-Sun
authors.initials: YS
authors.lastname: Chan
authors.forename: Jeffrey W-H
authors.initials: JW
authors.lastname: Fung
authors.forename: Winnie
authors.initials: W
authors.lastname: Chan
authors.forename: Yat-Yin
authors.initials: YY
authors.lastname: Lam
authors.forename: Cheuk-Man
authors.initials: CM
authors.lastname: Yu