Comparison of the Effects of Cardiac Resynchronization Therapy in Patients With Class II Versus Class III and IV Heart Failure (from the InSync/InSync ICD Italian Registry)††Conflicts of interest: ...

Full title: Comparison of the Effects of Cardiac Resynchronization Therapy in Patients With Class II Versus Class III and IV Heart Failure (from the InSync/InSync ICD Italian Registry)^††Conflicts of interest: Sergio Valsecchi and Alessandra Denaro are employees of Medtronic Italia, Rome, Italy.^,‡‡A list of centers and investigators participating in the InSync/InSync ICD Italian Registry is provided in the Appendix. Cardiac resynchronization therapy (CRT) is recommended for patients with New York Heart Association (NYHA) class III or IV heart failure and wide QRS complexes. The aim of this study was to compare the effects of CRT in patients in NYHA class II with those in NYHA class III or IV. Nine hundred fifty-two patients (188 in NYHA class II) consecutively implanted with biventricular devices and enrolled in a national observational registry were studied. Clinical outcomes were estimated after 12 months of CRT, and long-term survival was assessed. At a median follow-up of 16 months, significantly fewer major cardiovascular events were reported in patients in NYHA class II compared with NYHA class III or IV (rate 13 vs 23 per 100 patient-years of follow-up, p