Rationale and design of a randomized trial to assess the safety and efficacy of MultiPoint Pacing (MPP) in cardiac resynchronization therapy: The MPP Trial.

BACKGROUND: Although the majority of Class III congestive heart failure (HF) patients treated with cardiac resynchronization therapy (CRT) show a clinical benefit, up to 40% of patients do not respond to CRT. This paper reports the design of the MultiPoint Pacing (MPP) trial, a prospective, randomized, double-blind, controlled study to evaluate the safety and efficacy of CRT using MPP compared to standard biventricular (Bi-V) pacing.

METHODS: A maximum of 506 patients with a standard CRT-D indication will be enrolled at up to 50 US centers. All patients will be implanted with a CRT-D system (Quartet LV lead Model 1458Q with a Quadra CRT-D, Abbott) that can deliver both MPP and Bi-V pacing. Standard Bi-V pacing will be activated at implant. At 3 months postimplant, patients in whom the echocardiographic parameters during MPP are equal or better than during Bi-V pacing are randomized (1:1) to either an MPP or Bi-V arm.

RESULTS: The primary safety endpoint is freedom from system-related complications at 9 months. Each patient's response to CRT will be evaluated using a heart-failure clinical composite score, consisting of a change in NYHA functional class, patient global assessment score, HF events, and cardiovascular death. The primary efficacy endpoint is the proportion of responders in the MPP arm compared with the Bi-V arm between 3 and 9 months.

CONCLUSION: This trial seeks to evaluate whether MPP via a single quadripolar LV lead improves hemodynamic and clinical responses to CRT, both in clinical responders and nonresponders.