Citations

Background— QRS prolongation is associated with adverse outcomes in mostly white populations, but its clinical significance is not well established for other groups. We investigated the association between QRS duration and mortality in African Americans. Methods and Results— We analyzed data from 5146 African Americans in the Jackson Heart Study stratified by QRS duration on baseline 12-lead ECG. We defined QRS prolongation as QRS≥100 ms. We assessed the association between QRS duration and all-cause mortality using Cox proportional hazards models and reported the cumulative incidence of heart failure hospitalization. We identified factors associated with the development of QRS prolongation in patients with normal baseline QRS. At baseline, 30% (n=1528) of participants had QRS prolongation. The cumulative incidences of mortality and heart failure hospitalization were greater with versus without baseline QRS prolongation: 12.6% (95% confidence interval [CI], 11.0–14.4) versus 7.1% (95% CI, 6.3–8.0) and 8.2% (95% CI, 6.9–9.7) versus 4.4% (95% CI, 3.7–5.1), respectively. After risk adjustment, QRS prolongation was associated with increased mortality (hazard ratio, 1.27; 95% CI, 1.03–1.56; P =0.02). There was a linear relationship between QRS duration and mortality (hazard ratio per 10 ms increase, 1.06; 95% CI, 1.01–1.12). Older age, male sex, prior myocardial infarction, lower ejection fraction, left ventricular hypertrophy, and left ventricular dilatation were associated with the development of QRS prolongation. Conclusions— QRS prolongation in African Americans was associated with increased mortality and heart failure hospitalization. Factors associated with developing QRS prolongation included age, male sex, prior myocardial infarction, and left ventricular structural abnormalities.

Background— Cardiac resynchronization therapy with defibrillator (CRT-D) reduces morbidity and mortality among selected patients with heart failure in clinical trials. The effectiveness of this therapy in clinical practice has not been well studied. Methods and Results— We compared a cohort of 4471 patients from the National Cardiovascular Data Registry’s Implantable Cardioverter-Defibrillator (ICD) Registry hospitalized primarily for heart failure and who received CRT-D between April 1, 2006, and December 31, 2009, to a historical control cohort of 4888 patients with heart failure without CRT-D from the Acute Decompensated Heart Failure National Registry (ADHERE) hospitalized between January 1, 2002, and March 31, 2006. Both registries were linked with Medicare claims to evaluate longitudinal outcomes. We included patients from the ICD Registry with left ventricular ejection fraction ≤35% and QRS duration ≥120 ms who were admitted for heart failure. We used Cox proportional hazards models to compare outcomes with and without CRT-D after adjustment for important covariates. After multivariable adjustment, CRT-D was associated with lower 3-year risks of death (hazard ratio, 0.52; 95% confidence interval, 0.48–0.56; P <0.001), all-cause readmission (hazard ratio, 0.69; 95% confidence interval, 0.65–0.73; P <0.001), and cardiovascular readmission (hazard ratio, 0.60; 95% confidence interval, 0.56–0.64; P <0.001). The association of CRT-D with mortality did not vary significantly among subgroups defined by age, sex, race, QRS duration, and optimal medical therapy. Conclusions— CRT-D was associated with lower risks of mortality, all-cause readmission, and cardiovascular readmission than medical therapy alone among patients with heart failure in community practice.

Background— Patients with heart failure and atrial fibrillation are at higher risk of thromboembolic events than patients with heart failure alone. Yet, the use of anticoagulation therapy varies in clinical practice, especially among older patients, for whom its effectiveness is poorly understood. Methods and Results— Using clinical registry data linked to Medicare claims from 2005 to 2011, we examined outcomes of older patients hospitalized with heart failure and atrial fibrillation who newly initiated anticoagulation therapy at discharge. We used Cox proportional hazards models and inverse probability-weighted treatment estimates to adjust for selection bias. Main outcomes were mortality and readmission at 1 and 3 years. Among 5105 patients in 195 hospitals, 1623 (31.8%) started anticoagulation therapy at discharge. Treated patients had lower unadjusted rates of all-cause mortality (26.4% versus 42.8%; P <0.001) and all-cause readmission (58.4% versus 63.7%; P <0.001) at 1 year. After inverse weighting for the probability of treatment and adjustment for other discharge medications, anticoagulation therapy was associated with significantly lower 1-year mortality (hazard ratio, 0.70; 99% confidence interval, 0.59–0.82), but there was no statistically significant difference in the risk of all-cause readmission (hazard ratio, 0.89; 99% confidence interval, 0.78–1.01) or other readmission outcomes. Results were similar at 3 years. Conclusions— Initiation of anticoagulation therapy at hospital discharge was associated with improved mortality at 1 and 3 years but was not associated with improved cardiovascular readmission among older patients with heart failure and atrial fibrillation.

Background— Exercise intolerance is a hallmark of heart failure, but factors associated with impaired exercise capacity in heart failure with preserved ejection fraction are unclear. We hypothesized that in heart failure with preserved ejection fraction, the severity of resting ventricular and vascular dysfunction are associated with impairment in exercise tolerance as assessed by peak oxygen consumption. Methods and Results— Subjects with heart failure with preserved ejection fraction enrolled in the PhosphodiesteRasE-5 Inhibition to Improve CLinical Status And EXercise Capacity in Diastolic Heart Failure (RELAX) clinical trial (n=216) underwent baseline Doppler echocardiography, cardiopulmonary exercise testing, and cardiac MRI. RELAX participants were elderly (median age 69 years) and 48% were women. Ejection fraction (60%) and stroke volume (77 mL) were normal, while diastolic dysfunction (medial E / e ′, 16; deceleration time, 185 ms; left atrial volume, 44 mL/m 2 ) and increased arterial load (arterial elastance, 1.51 mm Hg/mL) were evident. Peak oxygen consumption was reduced (11.7 mLkg −1 min −1 , 1141 mL/min) and age, sex, body mass index, hemoglobin, and chronotropic response collectively explained 64% of the variance in raw peak oxygen consumption (mL/min). After adjustment for these variables, left ventricular structure (diastolic dimension [1.5%, P =0.008] and left ventricular mass [1.6%, P =0.008]), resting stroke volume (2.0%, P =0.002), left ventricular diastolic dysfunction (deceleration time [0.9%, P =0.03] and E / e ′ [1.4%, P =0.009]), and arterial function (arterial elastance [2.1%, P =0.002] and systemic arterial compliance [1.5%, P =0.007]), each explained only a small additional portion of the variance in peak oxygen consumption. Conclusions— In heart failure with preserved ejection fraction, potentially modifiable factors (obesity, anemia, and chronotropic incompetence) are strongly associated with exercise capacity, whereas resting measures of ventricular and vascular structure and function are not. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00763867

Background— Atrial fibrillation (AF) is common among patients with heart failure and preserved ejection fraction (HFpEF), but its clinical profile and impact on exercise capacity remain unclear. RELAX (Phosphodiesterase-5 Inhibition to Improve Clinical Status and Exercise Capacity in HFpEF) was a multicenter randomized trial testing the impact of sildenafil on peak V O 2 in stable outpatients with chronic HFpEF. We sought to compare clinical features and exercise capacity among patients with HFpEF who were in sinus rhythm (SR) or AF. Methods and Results— RELAX enrolled 216 patients with HFpEF, of whom 79 (37%) were in AF, 124 (57%) in SR, and 13 in other rhythms. Participants underwent baseline cardiopulmonary exercise testing, echocardiogram, biomarker assessment, and rhythm status assessment before randomization. Patients with AF were older than those in SR but had similar symptom severity, comorbidities, and renal function. β-blocker use and chronotropic indices were also similar. Despite comparable left ventricular size and mass, AF was associated with worse systolic (lower EF, stroke volume, and cardiac index) and diastolic (shorter deceleration time and larger left atria) function compared with SR. Pulmonary artery systolic pressure was higher in AF. Patients with AF had higher N-terminal pro-B-type natriuretic peptide, aldosterone, endothelin-1, troponin I, and C-telopeptide for type I collagen levels, suggesting more severe neurohumoral activation, myocyte necrosis, and fibrosis. Peak V O 2 was lower in AF, even after adjustment for age, sex, and chronotropic response, and V E /V CO 2 was higher. Conclusions— AF identifies an HFpEF cohort with more advanced disease and significantly reduced exercise capacity. These data suggest that evaluation of the impact of different rate or rhythm control strategies on exercise tolerance in patients with HFpEF and AF is warranted. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00763867.