Patients submitted to cardiac resynchronization may develop response patterns that are higher than expected, with normalization of clinical and echocardiographic parameters.
To analyze the clinical and echocardiographic characteristics of this population of super-responders, comparing them with the other patients submitted to cardiac resynchronization therapy.
A prospective, observational cohort study involving 146 patients consecutively submitted to cardiac resynchronization implants. Fisher's exact test and Mann-Whitney test were performed to compare the variables. Patients with ejection fraction > 50% and functional class I/II (New York Heart Association) were considered super-responders after 6 months of cardiac resynchronization therapy.
Mean age was 64.8 ± 11.1 years, with 69.8% of males, with a median ejection fraction of 29%, 71.5% with left bundle-branch block, 12% with right bundle-branch block associated with hemiblocks; 16.3% wearing a definitive cardiac pacemaker, 29.3% with ischemic cardiomyopathy, 59.4% with dilated cardiomyopathy, and 11.2% with Chagasic cardiomyopathy. Twenty-four (16.4%) super-responders were observed, and 13 (8.9%) showed normalization of the ejection fraction, left ventricular diastolic diameters and functional class. When compared to the non-super-responder patients, in relation to the pre-implantation characteristics, the super-responders were more often females (58.3% vs. 22.8%, p = 0.002), had higher body mass index (26.8 vs. 25.5, p = 0.013), higher baseline ejection fraction (31.0 vs. 26.9, p = 0.0003), and lower left ventricular diastolic diameters (65.9 mm vs. 72.6 mm, p = 0.0032). Ten patients (41.6% of super-responders) with right bundle-branch block and hemiblock progressed to super-responders, although there was only one patient with Chagas' disease among them, and only at the first assessment.
Super-responders had less advanced heart disease at baseline and no differences regarding the type of conduction disorder at baseline. Patients with right bundle-branch block and hemiblock, but without Chagasic heart disease may also progress as super-responders.
Heart Failure; Cardiac Resynchronization Therapy; Echocardiography; Defibrillators, Implantable