Cardiac resynchronization results in significant clinical improvement in patients who have moderate-to-severe heart failure and an intraventricular conduction delay.

for the Multicenter InSync Randomized Clinical Evaluation (MIRACLE) Study GroupBackground-Cardiac resynchronization therapy (CRT) has recently emerged as an effective treatment for patients with moderate to severe systolic heart failure and ventricular dyssynchrony. The purpose of the present study was to determine whether improvements in left ventricular (LV) size and function were associated with CRT. Methods and Results-Doppler echocardiograms were obtained at baseline and at 3 and 6 months after therapy in 323 patients enrolled in the Multicenter InSync Randomized Clinical Evaluation (MIRACLE) trial. Of these, 172 patients were randomized to CRT on and 151 patients to CRT off. Measurements were made of LV end-diastolic and end-systolic volumes, ejection fraction, LV mass, severity of mitral regurgitation (MR), peak transmitral velocities during early (E-wave) and late (A-wave) diastolic filling, and the myocardial performance index. At 6 months, CRT was associated with reduced end-diastolic and end-systolic volumes (both PϽ0.001), reduced LV mass (PϽ0.01), increased ejection fraction (PϽ0.001), reduced MR (PϽ0.001), and improved myocardial performance index (PϽ0.001) compared with control. ␤-Blocker treatment status did not influence the effect of CRT. Improvements with CRT were greater in patients with a nonischemic versus ischemic cause of heart failure. Conclusions-CRT in patients with moderate-to-severe heart failure who were treated with optimal medical therapy is associated with reverse LV remodeling, improved systolic and diastolic function, and decreased MR. LV remodeling likely contributes to the symptomatic benefits of CRT and may herald improved longer-term survival. (Circulation.

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Importance Iron deficiency is present in approximately 50% of patients with heart failure with reduced left ventricular ejection fraction (HFrEF) and is an independent predictor of reduced functional capacity and mortality. However, the efficacy of inexpensive, readily available oral iron supplementation in heart failure is unknown. Objective To test whether therapy with oral iron improves peak exercise capacity in patients with HFrEF and iron deficiency. Design, Setting, and Participants Phase 2, double-blind, placebo-controlled randomized clinical trial of patients with HFrEF (<40%) and iron deficiency, defined as serum ferritin level between 15–100 ng/ml or serum ferritin 101-299 ng/ml with transferrin saturation (Tsat) <20%. Patients were enrolled between September 2014 and November 2015 at 23 US sites. Interventions Oral iron polysaccharide (n = 111) or placebo (n = 114), 150 mg twice daily for 16 weeks. Main Outcomes and Measures The primary endpoint was a change in peak oxygen uptake (VO2), from baseline to 16 weeks. Secondary endpoints included changes in six minute walk distance; plasma NT-pro BNP levels; and health status as assessed by Kansas City Cardiomyopathy Questionnaire (KCCQ, range 0-100, higher scores reflect better quality of life). Results Among 225 randomized patients (median age 63 years, 36% women) 203 completed the study. The median baseline peak VO2 was 1196 ml/min (887, 1448 ml/min) in the oral iron group and 1167 ml/min (887, 1449 ml/min) in the placebo group. The primary endpoint, change in peak VO2, did not significantly differ between the oral iron and placebo groups (+23 ml/min vs −2 ml/min; difference, 21 ml/min [95% CI, −34 to +76]; P=.46). Similarly, at 16 weeks there were no significant differences between treatment groups in changes in 6-minute walk distance (−13, −32 to 6m), NT-pro BNP levels (159, −280 to 599 pg/ml), KCCQ Score (1, −2.4 to 4.4) or time to first adverse event (hazard ratio 0.85, 0.56 to 1.31), all p>0.05. Conclusion Among patients with HFrEF with iron deficiency, high-dose oral iron did not improve exercise capacity over 16 weeks. These results do not support use of oral iron supplementation in patients with HFrEF.