Previous randomized, controlled trials demonstrated that the use of speckle\tracking echocardiography for assessing the latest activated part might help the LV lead placement. applying exclusion criteria. The study cohort did not differ significantly from the total cohort (valuevaluevalue /th /thead Lateral vs. anterior0.690.55C0.87 0.01** Lateral vs. posterior0.840.74C0.96 0.01** Posterior vs. anterior0.770.60C0.990.04* Open in a separate window CI, confidence interval; LV, left ventricular. All models were adjusted for age, gender, left bundle branch block morphology, device type, atrial fibrillation, and ischaemic aetiology. * em p /em 0.05, ** em p /em 0.01 Echocardiographic response When echocardiographic response was evaluated within the lateral group, the mean increase of EF was 7.3% (9.7), and based on our definition of reverse remodelling, 65.5% of them were identified as echocardiographic responders to CRT. We aimed to find additional factors to further improve the clinical outcome of CRT patients and found a significant association between IED and echocardiographic response (area under the ROC curve, 0.63; 95% CI 0.53C0.73; em P Carprofen /em ?=?0.012) in the lateral group, with an optimal cut\off value of 110?ms based on the ROC analysis ( em Figure /em em 3 /em ). Assessing by logistical regression, those with an IED longer than 110?ms showed 2.1 times higher odds of improvement in echocardiographic response 6?months after CRT implantation (odds ratio 2.1; 95% CI 0.99C4.24; em P /em ?=?0.05). We did not find such association between IED and echocardiographic response in patients with an anterior or posterior LV lead locations (area under the Carprofen ROC curve 0.30 and 0.57). We used an IED threshold of 110?ms for further analysis. Patients with lateral position and an IED??110?ms showed greater improvement in LVEF absolute percent change 6?months after the implantation (baseline LVEF 27.4??6.0% vs. 6?months LVEF 36.4??9.2%) compared with those with lateral position, but an IED? ?110?ms (baseline LVEF 27.7??7.1% vs. 6?months LVEF 33.1??9.2%) ( em P Carprofen /em ?=?0.02). Open in a separate window Figure 3 Receiver operating characteristic (ROC) curve of interlead CXADR 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 0.53C0.73; em P /em ?=?0.012) in the lateral group, with an optimal cut\off value of 110?ms. Discussion The main findings of our study can be summarized as follows. Long\term clinical outcome of patients undergoing CRT implantation depends on the position of the LV lead. Lateral position was associated with a significantly lower risk of all\cause mortality compared with anterior and posterior positions, which was also confirmed by multivariate analysis. To our knowledge, our current Carprofen study is the first to demonstrate in a real\world patient population that lateral LV lead position is superior to posterior position when investigating long\term all\cause mortality. Furthermore, we found that IED was significantly longer in the lateral group and associated with 2.1 times higher odds for echocardiographic response over 110?ms of IED. Optimizing response continues to be an important goal for CRT and available data on the associations of LV lead locations with long\term clinical outcomes are scarce and controversial. Previous randomized, controlled trials demonstrated that the use of speckle\tracking echocardiography for assessing the latest activated part might help the LV lead placement. This method is associated with better subsequent outcome compared with routine approach. 32 , 33 However, this method could be limited by the anatomical location of coronary sinus side branches; thus, our method with evaluating the latest activated part by measuring the RVCLV interlead delay during CRT implantation seems to be superior. The effect of left ventricular lead position on all\cause mortality The Multicenter Automatic Defibrillator Implantation Trial with Cardiac Resynchronization Therapy mid\term analysis found that LV apical lead position is associated with adverse clinical outcomes during mid\term follow\up in CRT\D patients, but in their analysis, lateral LV lead location did not emerge superior to anterior or posterior LV lead positions in terms of reduction in HF or death, HF only, and death alone. 15.