Implant of Cardiac Resynchronization Therapy Device in Patients with High Percentage of Right Ventricular Pacing and Refractory Heart Failure

Background: Implant of a cardiac resynchronization therapy device in patients with pacemaker or implantable cardioverter defibrillator who develop heart failure with left ventricular dysfunction is controversial. Objective: The aim of this study was to evaluate the outcome of these patients after upgrading to cardiac resynchronization therapy. Methods: Patients undergoing therapy upgrade between 2011 and 2015 were evaluated. Results: A total of 21 patients were included with mean age of 70.7±10.8 years. Mean QRS duration was 180.9±23.2 ms and left ventricular ejection fraction was 26.8 ± 7.7%. The frequency of right ventricular pacing was 90.5±19.3%. Ten patients were in functional class II and 11 in FC III. The implant was successful in 18 patients (85.7%). Left ventricular ejection fraction was 33.9±10.4% one year after upgrading (p=0.028). Among the total number of patients, 13 improved their functional class in at least one category and only 4 were rehospitalized due to heart failure (p=0.048). The rate of complications was 14.28%. Conclusions: Therapy upgrade improved symptoms and reduced hospitalizations due to heart failure.