Purpose: The MultiPoint™ (MPP) Pacing IDE Study assessed the safety and efficacy of the MPP feature in heart failure (HF) patients indicated for a cardiac resynchronization therapy defibrillator (CRT-D).
Methods: This multicenter study enrolled and followed 506 patients with a standard CRT-D indication who were implanted with a CRT-D system (Quartet™ LV lead Model 1458Q with a Quadra CRT-D, St. Jude Medical) capable of delivering either Quadripolar Bi-Ventricular (Bi-V) pacing or MPP. Quadripolar Bi-V pacing was activated at implant. At 3 months post-implant, patients\u27 responder status was assessed, both responders and non-responders were randomized, and 1:1 randomization (Bi-V or MPP) was stratified by the patient\u27s responder status (Defined by the Clinical Composite Score). The primary safety end point was freedom from system-related complications through 9 months. The primary efficacy end point was non-inferiority of the proportion of non-responders in the MPP arm compared with the Bi-V arm between 3 and 9 months.
Results: The CRT-D system was successfully implanted in 455 of the 469 attempts (97%). 381 patients were randomized to either Bi-V (n = 180) or MPP (n = 201) at 3 months. Baseline characteristics for both arms were comparable. The primary safety end point (93.2%, 97.5% lower confidence bound 90.4%) was greater than the objective performance criterion of 75% and therefore met. The primary efficacy end point was met for both intention-to-treat (ITT) and As-treated populations in 381 randomized patients (ITT, p = 0.013 and As-treated, p = 0.008, respectively). For patients (n = 52) in the MPP arm programmed with wide cathode spacing (≥ 30 mm) and the shortest intraventricular timing delay (5 ms), MPP provided significantly higher clinical responder rate up to 87% (Fig A, p = 0.003 vs. \u3c 30 mm) and converted 100% of non-responders to responders (Fig B, p = 0.006 vs. \u3c 30 mm).
Conclusion: MPP was shown to be safe and effective and the study met the pre-specified hypothesis that the response to MPP is non-inferior to Quadripolar Bi-V pacing. When MPP was programmed with cathode spacing \u3e 30 mm and 5 ms LV delay, the CRT response was greatest (87%) and all non-responders were converted to responders. View largeDownload slid