• Arrhythmias
• Cardiology Clinical Trials
• Interventional Techniques & Devices

• Cardiology & Cardiovascular Medicine

The Alternate Site Cardiac Resynchronization study [ALSYNC; NCT01277783] investigated the safety and efficacy of left ventricular endocardial (LVE) pacing using a novel atrial transseptal system for lead delivery. John M. Morgan, MD, University of Southampton, Southampton, United Kingdom, reported that using a lead delivery system with a single pectoral incision for LVE pacing is both safe and feasible.

The benefits of cardiac resynchronization therapy (CRT) have been well established; however, approximately 10% of patients are not able to undergo device implantation because of procedural failures [Cleland JG et al. Eur Heart J 2013]. In addition, approximately, 30% of patients fail to respond to biventricular pacing [Sohaib SMA et al. Eur J Heart Fail 2013]. LV endocardial pacing has the benefit of being a predictable procedure that allows a wide choice of left ventricular surface for pacing, with the potential for an improved CRT response. Challenges to the implementation of this approach include the need for safe and simple implantation tools and the need to better understand and control potential complications. The model 3830 system is composed of a deflectable catheter-in-catheter with a radiofrequency-powered transseptal puncture guidewire and dilator, which enable a subclavian approach and targeted LVE lead delivery.

ALSYNC was a noncomparative, nonrandomized, prospective clinical study conducted at 16 European and 2 Canadian centers. The primary objective was survival of LVE lead and delivery system-related complications at 6 months. Complications were defined as adverse events resulting in death, confirmed stroke, termination of significant device function, or invasive intervention. There was a minimum of 12 months' follow-up, with visits at 1, 3, 6, and 12 months and biannually after 12 months.

Eligible patients were candidates for CRT in whom prior coronary sinus left ventricular lead implantation had failed, those with suboptimal coronary sinus anatomy, and those who were nonresponders after ≥6 months of CRT. Subjects also had to be able to take oral vitamin K antagonists (international normalized ratio of 2 to 4 with a target of 3). The study comprised 138 subjects with a median age of 68 years; 22.5% were CRT nonresponders, 50% had atrial fibrillation, 78% had undergone failed prior implantation, and 76.1% were on anticoagulants. Most subjects were in New York Heart Association class III (68.1%) or IV (7.2%).

The primary end point occurred in 23 patients (25 total events) during the first 6 months after the procedure. There were 2 strokes during the first 6 months, neither of which was disabling (Rankin score < 3). Four transient ischemic attacks were reported during the first 6 months, 1 of which did not meet the criteria for the primary end point. Ten patients died during the 6 months of follow-up; only 1 death was related to the implantation procedure. Mitral regurgitation improved in the majority of subjects. In the subgroup of subjects originally considered nonresponders, between 50% and 60% responded to LVE therapy. Clinical outcomes are shown in Table 1.

The limitations of this device include the lack of visual guidance for locating the fossa ovalis and performing a transseptal puncture. The risk-benefit trade-off was also difficult to assess. Follow-up in this study is ongoing and will be reported at a later date; however, the preliminary findings support the further study of an atrial transseptal LVE lead system implanted from a single pectoral incision in patients who otherwise have limited CRT options.

• © 2014 MD Conference Express®