Abstract 819: Natural History of Candidates for Cardiac Resynchronization Therapy: Insights from the COMPANION Study
Although the natural history of patients (pts) with systolic dysfunction or left bundle branch block is well described, the natural history of pts who are candidates for cardiac resynchronization therapy (CRT) is less well-known. Our objective was to characterize the baseline clinical characteristics of CRT candidates over the time interval prior to receiving this therapy. The COMPANION study collected the duration of heart failure (HFDur) since diagnosis. Pts were assigned to one of five groups based upon HFDur, ranging from recent diagnosis (0.6 years) to as long as 10 years. Twenty baseline clinical characteristics were examined individually to determine whether a significant association existed between them and HFDur. COMPANION randomized 1520 pts, characterized as male (67%), NYHA Class III (86%), mean age 67 years, mean EF=21%, ischemic etiology (55%), and mean QRS=159 ms. Of twenty baseline clinical variables, 11 were found to be significantly associated with HFDur as shown below: Variables not showing significant association with HRDur included resting heart rate, age, sex, bundle branch morphology, systolic BP, and HF drug use. In the COMPANION study, markers traditionally associated with greater mortality (e.g., atrial fibrillation, renal disease, remodeling, diabetes, QRS width, and LVEF) were found to worsen with time subsequent to diagnosis but prior to study entry. Further work is needed to confirm these results prospectively, to determine whether HFDur is related to response, and whether earlier intervention with CRT may be justified.