Cardiac contractility modulation for patient with refractory heart failure: an updated evidence-based review

Heart failure is the cardiovascular epidemic of the twenty-first century, with poor prognosis and quality of life despite optimized medical treatment. Despite over the last decade significant improvements, with a major impact on morbidity and mortality, have been made in therapy for heart failure with reduced ejection fraction, little progress was made in the development of devices, with the implantable defibrillator indicated for patients with left ventricle ejection fraction ≤ 35% and cardiac resynchronization therapy for those with QRS ≥ 130 ms and evidence of left bundle branch block. Nevertheless, only a third of patients meet these criteria and a high percentage of patients are non-responders in terms of improving symptoms. Nowadays, in patients with symptomatic heart failure with ejection fraction between 25% and 45% and QRS < 130 ms, not eligible for cardiac resynchronization, the cardiac contractility modulation (CCM) represents a concrete therapeutic option, having proved to be safe and effective in reducing hospitalizations for heart failure and improving symptoms, functional capacity, and quality of life. The aim of this review is therefore to summarize the pathophysiological mechanisms, the current indications, and the recent developments regarding the new applications of the CCM for patients with chronic heart failure.