LAUSR

Shortly after the turn of the millennium, cardiac resynchronization therapy (CRT) was developed as a powerful treatment for heart failure with reduced ejection fraction (HFrEF) accompanied by significant electromechanical dysynchrony [1,2]. Despite the early success of CRT, it was clear that therewas room for improvement.With early generation unipolar and bipolar LV pacing leads, there was a small but important rate of implant failure. Although implant tools improved, LV leads continued to provemore prone to dislodgement than standard endocardial pacing/defibrillation leads, and CRT pacing was also sometimes hindered by phrenic nerve stimulation (PNS) e with both of these problems leading to lead revision procedures and, occasionally, deactivation of LV pacing. Additionally, even with successful, uncomplicated implants, CRT has long been associated with a bothersome rate of clinical non-response [3]. In an effort to address some of these issues, in late 2011, the first quadripolar pacing leads were introduced to the US market, and were rapidly adopted. Single-arm observational studies of the first two quadripolar lead families showed high implant success rates, low dislodgment rates, good chronic pacing thresholds, and an ability to resolve most cases of PNS via device reprogramming [4e6]. It has, however, taken several years since the launch of quadripolar pacing leads for data to emerge proving their clinical value relative to conventional bipolar leads. In the current issue of IPEJ, Rijal and colleagues add to the growing literature on this topic, with a large, single-center series comparing the outcomes of CRT recipients treated with either quadripolar or bipolar leads at their center [7]. The authors scanned the ICD registry and electronic health records from their institution to identify a total of 1441 patients (292 quadripolar and 1149 bipolar) who had a CRT device implanted between January 2011 and December 2014. Baseline demographic and clinical characteristics between the two groups were comparable, except for the fact that those receiving quadripolar leads were slightly younger and had an increased incidence of diabetes mellitus. The procedures were carried out by wellexperienced electrophysiologists. Both de novo and CRT upgrades were included. Quadripolar leads from both St. Jude (Quartet) and Medtronic (Attain Performa) were used. The primary end-point was a composite of LV lead implant failure, dislodgment, or LV pacing deactivation for PNS in the first 12 months after the index procedure. Secondary outcomes included hospitalizations and mortality. For the vast majority (85%) of the patients, follow-up data for one year was available, with the overall