Multisite Pacing as a Supplemental Treatment of Congestive Heart Failure: Preliminary Results of the Medtronic Inc. InSync Study

TLDR

The InSync study reports early safety and efficacy data for a multisite pacemaker and left‑ventricular pacing leads implanted via a cardiac vein as a supplemental therapy for refractory congestive heart failure. The trial enrolled 68 patients (average age 66 ± 10 years, mean LVEF 21 ± 9 %, 63 % NYHA III, 37 % NYHA IV). Over 10 months, the system was successfully implanted in 84 % of patients with no implant‑related complications, and surviving patients showed significant improvements in NYHA class, Minnesota Living with Heart Failure scores, and 6‑minute walk distance, accompanied by QRS narrowing and reduced interventricular delay, confirming the feasibility and encouraging further evaluation of this multisite pacing approach.

Abstract

This report describes the initial results of the “InSync” study, a European and Canadian multicenter trial that examines the safety and efficacy of a multisite pacemaker (Medtronic InSync) and of left ventricular pacing leads (Medtronic 2187 and 2188) implanted via a cardiac vein as a supplemental treatment of refractory congestive heart failure. Over a 10‐month period, the system was implanted successfully in 68 of the 81 (84%) patients who had been enrolled in the study. The 68 patients were, on average, 66 ± 10 years old, had a mean left ventricular ejection fraction (LVEF) = 21 %± 9%, and 63% were in NYHA functional Class III and 37% were in Class IV. No system implant related complication occurred. During follow‐up, 7 of 10 patients who exited the study had died, 4 suddenly. There was a clinical benefit among surviving patients, which was corroborated by a significant improvement in NYHA functional class and in the Minnesota Living with Heart Failure Quality of Life Questionnaire Score (MLS) and by a longer distance covered during a 6‐minute walk test. This clinical improvement was associated with a significant narrowing of the paced QRS complex during biventricular pacing, a significant decrease in the interventricular mechanical delay, and a trend towards an increase in the duration of ventricular filling. These encouraging preliminary results confirm the feasibility and reliability of this new multisite pacing system in the management of dilated cardiomyopathy and support the continuation of further evaluations of this complementary treatment of refractory congestive heart failure.