title: Device-measured physical activity versus six-minute walk test as a predictor of reverse remodeling and outcome after cardiac resynchronization therapy for heart failure.
abstract: Implanted devices can provide objective assessment of physical activity over prolonged periods. The purpose of this study was to investigate the prognostic value of device-measured physical activity data compared with a six-minute walk test (6MWT) in predicting clinical response to cardiac resynchronization therapy (CRT). This was a single-center study in which patients who underwent CRT for standard indications were evaluated. Daily physical activity and 6MWT were evaluated postimplant at 1, 3, and 6 months. The primary end point was a composite of heart failure hospitalization, transplant, left ventricular (LV) assist device, and all-cause death at 3 years. Echocardiographic response, defined as a ≥10% improvement in LV ejection fraction (LVEF), at 6 months was the secondary end point. About 164 patients were included: average age was 67.3 ± 12.9 years, 77% were men, baseline LVEF was 25% ± 7%. Kaplan-Meier curves showed superior freedom from the composite end point in the highest tertile of both 6MWT and physical activity compared with the lowest tertile (41 vs 23 cases, respectively, p <0.001) for 6MWT and for activity (22 vs 7 cases, respectively, p = 0.001). In an adjusted multivariate model, independent predictors of improved clinical outcome included 1-month physical activity (hazard ratio 0.546, 95% confidence interval [CI] 0.361 to 0.824, p = 0.004) and 6MWT (hazard ratio 0.581, 95% CI 0.425 to 0.795, p = 0.001). An additional hour of higher activity at 1 month translated to a 1.38 times (95% CI 1.075 to 1.753, p = 0.011) higher likelihood of improved echocardiographic response. In conclusion, device-based measures of physical activity may be useful in predicting echocardiographic reverse remodeling and long-term clinical outcome in patients receiving CRT.
authors.affiliation: Department of Cardiology, Massachusetts General Hospital Heart Center, Harvard Medical School, Boston, Massachusetts; Department of Cardiology, Semmelweis University Heart and Vascular Center, Budapest, Hungary.
authors.forename: Eszter Maria
authors.initials: EM
authors.lastname: Vegh
authors.affiliation: Department of Cardiology, Massachusetts General Hospital Heart Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Jagdesh
authors.initials: J
authors.lastname: Kandala
authors.affiliation: Department of Cardiology, Massachusetts General Hospital Heart Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Mary
authors.initials: M
authors.lastname: Orencole
authors.affiliation: Department of Cardiology, Massachusetts General Hospital Heart Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Gaurav A
authors.initials: GA
authors.lastname: Upadhyay
authors.affiliation: Department of Cardiology, Massachusetts General Hospital Heart Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Ajay
authors.initials: A
authors.lastname: Sharma
authors.affiliation: Department of Cardiology, Massachusetts General Hospital Heart Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Miller
authors.affiliation: Department of Cardiology, Semmelweis University Heart and Vascular Center, Budapest, Hungary.
authors.forename: Bela
authors.initials: B
authors.lastname: Merkely
authors.affiliation: Department of Cardiology, Massachusetts General Hospital Heart Center, Harvard Medical School, Boston, Massachusetts.
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Parks
authors.affiliation: Department of Cardiology, Massachusetts General Hospital Heart Center, Harvard Medical School, Boston, Massachusetts. Electronic address: jsingh@partners.org.
authors.forename: Jagmeet P
authors.initials: JP
authors.lastname: Singh
mesh_terms: D000368:Aged; D058406:Cardiac Resynchronization Therapy; D004452:Echocardiography; D005260:Female; D005544:Forecasting / Q000379:methods; D006333:Heart Failure / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D009043:Motor Activity; D016896:Treatment Outcome; D016277:Ventricular Function, Left; D020257:Ventricular Remodeling; D016138:Walking