Lateral left ventricular lead position is superior to posterior position in long-term outcome of patients who underwent cardiac resynchronization therapy

Abstract

Aims: Preferring side branch of coronary sinus during cardiac resynchronization therapy (CRT) implantation has been empirical due to the limited data on the association of left ventricular (LV) lead position and long-term clinical outcome. We evaluated the long-term all-cause mortality by LV lead non-apical positions and further characterized them by interlead electrical delay (IED).

Methods and results: In our retrospective database, 2087 patients who underwent CRT implantation were registered between 2000 and 2018. Those with non-apical LV lead locations were classified into anterior (n = 108), posterior (n = 643), and lateral (n = 1336) groups. All-cause mortality was assessed by Kaplan-Meier and Cox analyses. Echocardiographic response was measured 6 months after CRT implantation. During the median follow-up time of 3.7 years, 1150 (55.1%) patients died-710 (53.1%) with lateral, 78 (72.2%) with anterior, and 362 (56.3%) with posterior positions. When we investigated the risk of all-cause mortality, there was a significantly lower rate of death in patients with lateral LV lead location when compared with those with an anterior (P < 0.01) or posterior (P < 0.01) position. Multivariate analysis after adjustment for relevant clinical covariates such as age, sex, ischaemic aetiology, left bundle branch block morphology, atrial fibrillation, and device type revealed consistent results that lateral position is associated with a significant risk reduction of all-cause mortality when compared with anterior [hazard ratio 0.69; 95% confidence interval (CI) 0.55-0.87; P < 0.01] or posterior (hazard ratio 0.84; 95% CI 0.74-0.96; P < 0.01) position. When echocardiographic response was evaluated within the lateral group, patients with an IED longer than 110 ms (area under the receiver operating characteristic curve, 0.63; 95% CI 0.53-0.73; P = 0.012) showed 2.1 times higher odds of improvement in echocardiographic response 6 months after the implantation.

Conclusions: In this study, we proved in a real-world patient population that after CRT implantation, lateral LV lead location was associated with long-term mortality benefit and is superior to both anterior and posterior positions. Moreover, patients with this position showed the greatest echocardiographic response over 110 ms IED.

Keywords: CRT long-term outcome; Interlead electrical delay; Lateral left ventricular lead; Left ventricular lead position; RV-LV delay.

Figure 1

Interlead electrical delay (IED) length by left ventricular lead locations. IED was significantly longer in the lateral group than in others (lateral vs. anterior P < 0.01) (lateral vs. posterior P < 0.01). The boxes represent the 95% confidence interval, with the whiskers representing the minimum and maximum range. The central horizontal lines within the boxes represent the median levels for each group.

Figure 2

Kaplan–Meier estimates of the probability of survival by left ventricular (LV) lead locations. Patients with lateral LV lead position had significantly better outcome compared with other locations.

Figure 3

Receiver operating characteristic (ROC) curve of interlead electrical delay (IED) length to echocardiographic response in patients with lateral left ventricular lead location. There was a significant association between IED and echocardiographic response (area under the ROC curve, 0.63; 95% confidence interval 0.53–0.73; P = 0.012) in the lateral group, with an optimal cut‐off value of 110 ms.