Cardiac resynchronization therapy non-responder to responder conversion rate in the MORE-CRT MPP trial
Christophe Leclercq1, Haran Burri2, Peter Paul Delnoy3
1Service de Cardiologie et Maladies Vasculaires, Université de Rennes I, CICIT 804, CHU Pontchaillou Rennes, 2, rue Henri le Guilloux 35033 Rennes Cédex 09, Rennes 35033, France.
Aims:
To assess the impact of MultiPoint™ Pacing (MPP) in cardiac resynchronization therapy (CRT) non-responders after 6 months of standard biventricular pacing (BiVP).
Methods And Results:
The trial enrolled 5850 patients who planned to receive a CRT device. The echocardiography core laboratory assessed CRT response before implant and after 6 months of BiVP; non-response to BiVP was defined as <15% relative reduction in left ventricular end-systolic volume (LVESV). Echocardiographic non-responders were randomized in a 1:1 ratio to receive MPP (541 patients) or continued BiVP (570 patients) for an additional 6 months and evaluated the conversion rate to the echocardiographic response. The characteristics of both groups at randomization were comparable. The percentage of non-responder patients who became responders to CRT therapy was 29.4% in the MPP arm and 30.4% in the BIVP arm (P = 0.743). In patients with ≥30 mm spacing between the two left ventricular pacing sites (MPP-AS), identified during the first phase as a potential beneficial subgroup, no significant difference in the conversion rate was observed.
Conclusion:
Our trial shows that ∼30% of patients, who do not respond to CRT in the first 6 months, experience significant reverse remodelling in the following 6 months. This finding suggests that CRT benefit may be delayed or slowly incremental in a relevant proportion of patients and that the percentage of CRT responders may be higher than what has been described in short-/middle-term studies. MultiPoint™ Pacing does not improve CRT response in non-responders to BiVP, even with MPP-AS.
