MULTISITE PACING AS A SUPPLEMENTAL TREATMENT OF CONGESTIVE-HEART-FAILURE - PRELIMINARY-RESULTS OF THE MEDTRONIC INC. INSYNC STUDY

This report describes the initial results of the ''lnSync'' study, a E uropean and Canadian multicenter trial that examines the safety and ef ficacy of a multisite pacemaker (Medtronic InSync) and of left ventric ular pacing leads (Medtronic 2187 and 2288) implanted via a cardiac ve in as a supplemental treatment of refractory congestive heart failure. Over a 10-month period, the system was implanted successfully in 68 o f the 81 (84%) patients who had been enrolled in the study. The 68 pat ients were, on average, 66 +/- 10 years old, had a mean left ventricul ar ejection fraction (LVEF) = 21% +/- 9%, and 63% were in NYHA functio nal Class III and 37% were in Class IV. No system implant related comp lication occurred. During follow-up, 7 of 10 patients who exited the s tudy had died, 4 suddenly. There was a clinical benefit among survivin g patients, which was corroborated by a significant improvement in NYH A functional class and in the Minnesota Living with Heart Failure Qual ity 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 biventri cular pacing, a significant decrease in the interventricular mechanica l delay, and a trend towards an increase in the duration of ventricula r filling. These encouraging preliminary results confirm the feasibili ty and reliability of this new multisite pacing system in the manageme nt of dilated cardiomyopathy and support the continuation of further e valuations of this complementary treatment of refractory congestive he art failure.