Baseline functional capacity and the benefit of cardiac resynchronization therapy in patients with mildly symptomatic heart failure enrolled in MADIT-CRT
ABSTRACT Mildly symptomatic heart failure (HF) patients were shown to derive substantial clinical benefit from cardiac resynchronization therapy with defibrillator (CRT-D) in Multicenter Automatic Defibrillator Implantation Trial in Cardiac Resynchronization Therapy. However, the relationship between functional capacity (FC) and CRT-D benefit in the trial was not assessed.
To evaluate the association between FC and response to CRT-D in Multicenter Automatic Defibrillator Implantation Trial in Cardiac Resynchronization Therapy.
We evaluated the association between preimplantation FC and the benefit of CRT-D in reducing the risk of HF or death in Multicenter Automatic Defibrillator Implantation Trial in Cardiac Resynchronization Therapy. Functional status was assessed by a 6-minute walk test (6MWT), dichotomized at the median value as poor (<350 m) or good (≥350 m).
Implantable cardioverter-defibrillator-only patients with a poor FC had an adjusted 73% increased risk for HF or death (P <.001) and a 2.4-fold (P = .001) increased risk for all-cause mortality. CRT-D therapy was associated with 63% (P <.001) and 44% (P <.001) reductions in the risk of HF or death among left bundle branch block patients with a poor FC and a good FC, respectively (P for interaction = .10). Among left bundle branch block patients with a poor FC, CRT-D was also associated with a significant reduction in the risk of all-cause mortality (hazard ratio 0.52; P = .015) whereas the survival benefit of CRT-D was not observed among those who had a higher FC at enrollment (hazard ratio 1.01; P = .98; P for interaction = .10).
Poor FC is a strong independent predictor for mortality and HF events in patients with mildly symptomatic HF. Left bundle branch block patients with poor baseline FC derive a pronounced benefit from CRT-D, manifest by a significant reduction in mortality.
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ABSTRACT: The purpose of this study was to investigate the prognostic value of change in distance walked in 6 min in chronic heart failure (CHF). The strongest indication for the 6-min walking test (6MWT) is for measuring the response to therapeutic interventions in patients with CHF. Whether the increase in distance walked after a therapeutic intervention translates into improved clinical outcome is largely unknwon. We studied 476 CHF patients with left ventricular systolic dysfunction who were referred to our institution for adjustment of heart failure therapy because of persisting or worsening symptoms. Adjustment of therapy involved four classes of drugs: angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, beta-blockers, loop diuretics, and aldosterone antagonists. A standardized 6MWT was performed at baseline and at discharge. After 15.2 +/- 8 days, the distance walked increased from 326 +/- 107 m to 408 +/- 109 m (+25%; p = 0.001). During a mean follow-up of 23.9 months, 94 patients died and 12 patients underwent cardiac transplantation. Among a set of variables, New York Heart Association functional class (p = 0.02), serum creatinine concentration (p = 0.01), left ventricular ejection fraction (p = 0.002), distance walked at baseline (p = 0.0002), and change in distance walked (p = 0.002) were significant independent predictors of survival. When the patients were divided into two subgroups according to the median value of the distance walked at baseline, the increase in walking distance was significantly associated with survival only in the subgroup of patients who walked <340 m at baseline. Our data indicate that repeating a 6MWT after drug intervention provides independent prognostic information in CHF patients with more compromised exercise capacity.Journal of the American College of Cardiology 08/2006; 48(1):99-105. DOI:10.1016/j.jacc.2006.02.061 · 16.50 Impact Factor
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ABSTRACT: The 6-min walk test (6'WT) is a simple measure of functional capacity and predicts survival in patients with moderate heart failure (HF). To assess the role of the 6'WT in the evaluation of patients with advanced HF, 45 patients (age 49 +/- 8 years, mean +/- SD; New York Heart Association class 3.3 +/- 0.6; left ventricular ejection fraction 0.20 +/- 0.06; right ventricular ejection fraction 0.31 +/- 0.11) underwent symptom-limited cardiopulmonary exercise testing and the 6'WT during cardiac transplant evaluation. Mean 6'WT distance ambulated was 310 +/- 100 m and peak oxygen uptake (peak Vo2) was 12.2 +/- 4.5 mL/kg/min. There was a significant correlation between 6'WT distance ambulated and peak Vo2 (r = 0.64, p < 0.001). Multivariate analysis of patient characteristics, resting hemodynamics, and 6'WT results identified the distance ambulated during the 6'WT as the strongest predictor of peak Vo2 (p < 0.001). 6'WT distance ambulated less than 300 m predicted an increased likelihood of death or pretransplant hospital admission for continuous inotropic or mechanical support within 6 months (p = 0.04), but did not predict long-term overall or event-free survival with a mean follow-up of 62 weeks. Peak Vo2 was the best predictor of long-term overall and event-free survival. In patients with advanced HF evaluated for cardiac transplantation, distance ambulated during the 6'WT predicts (1) peak Vo2 and (2) short-term event-free survival.Chest 09/1996; 110(2):325-32. DOI:10.1378/chest.110.2.325 · 7.48 Impact Factor
Article: Lang RM, Bierig M, Devereux RB, Flachskampf FA, Foster E, Pellikka PA, et al. Recommendations for Chamber Quantification: a Report from the American Society of Echocardiography's Guidelines and Standards Committee and the Chamber Quantification Writing Group, Developed in Conjunction with the European Association of Echocardiography, a Branch of the European Society of CardiologyJournal of the American Society of Echocardiography: official publication of the American Society of Echocardiography 01/2006; 18(12):1440-63. DOI:10.1016/j.echo.2005.10.005 · 4.06 Impact Factor