Abraham WT, et al. - Researchers wanted to confirm the results of a subgroup analysis of the previous FIX-HF-5 (Evaluate Safety and Efficacy of the OPTIMIZER System in Subjects With Moderate-to-Severe Heart Failure) study, which found that cardiac contractility modulation (CCM, a therapy consisting of nonexcitatory electrical signals delivered to the heart during the absolute refractory period) can improve exercise tolerance (ET) and quality of life in patients with heart failure (HF) with ejection fractions between 25% and 45%. They examined 160 patients with New York Heart Association (NYHA) functional class III or IV symptoms, QRS duration <130 ms, and ejection fraction ≥25% and ≤45%. These subjects were randomized to continued medical therapy (control, n = 86) or CCM (treatment, n = 74, unblinded) for 24 weeks. According to findings, CCM was safe and led to improvements in exercise tolerance and quality of life in the specified group of HF patients. They also observed that fewer HF hospitalizations with CCM.