Study Design

Study Design:

Patients Enrolled: 636
NYHA Class: NYHA Class II, III, or IV
Mean Follow Up: 6 months
Mean Patient Age: Mean age 68 years

Patient Populations:

Patient criteria for the InSync-ICD trial were: NYHA Class II, III, or IV QRS duration of =130 ms. LVEF =35%. LVEDD =55 millimeters by echo measurement. Stable HF controlled with appropriate drug therapy for at least 1 month. On an ACE inhibitor or substitute, if tolerated. If on beta blocker therapy, a stable regimen maintained for over 3 months prior to enrollment. Indication for an ICD.

Drug/Procedures Used:

Patients with NYHA Class II-IV heart failure, QRS duration of =130 ms, LVEF =35%, LVEDD =55 mm, who were stabilized on appropriate medical therapy, and indicated for an ICD were randomized to either implantation of the device with the cardiac resynchronization mode on, or to a control group, in whom the cardiac resynchronization mode was turned off. The ICD function was active in all patients. In all, there were a total of 636 subjects of NYHA Class II (n=215) or NYHA Class III/IV (n=421). Of the Class II subjects, 192 were randomized to either control or CRT. Of Class III/IV subjects, 362 were randomized to either control or CRT. In all, 371 patients received the implants. Patients in both the treatment and control groups were similar as far as heart rate, 6-minute walk distance, systolic and diastolic blood pressures, and the use of diuretic, ACE-I or ARB, and beta-blocker use. Similar percentages of patients with NYHA Class III were present in both groups (89% of controls and 88% in treatment group), and heart failure of ischemic etiology was present in 74% and 63%, respectively.