Modulation of Cardiac Contractility – a New Method in the Treatment of Heart Failure

Abstract

The review analyzes new treatment for patients with chronic heart failure (CHF) with low ejection fraction – cardiac contractility modulation (CCM). CCM is carried out by supplying electric signals to an absolutely refractory ventricular myocardium, to elicit a positive inotropic effect without increasing myocardial oxygen consumption. These effects are independent on QRS duration; consequently, the therapy might be beneficial for patients who are not candidates for cardiac resynchronization therapy (CRT). It should be noted that the use of CCM treatment of CHF should begin only with maximum active therapy when its efficacy is not enough. It is not an alternative, but complement to the most active treatment of patients. Clinical studies primarily focused on patients with normal QRS duration because the CPT is optimal treatment of patients with prolonged QRS. The article focuses on the prerequisites for the development of the method and discusses the results obtained when evaluating the clinical efficacy and safety of treatment of patients with CHF in randomized clinical trials FIX-HF-3 (n=25), FIX-HF-4 (n=164), FIX-HF-5 (n=428). The total number of patients included into these studies was 617 people. Baseline patient characteristics were similar for all 3 studies. All participants received optimal medical therapy, had a normal QRS duration. All patients were II and III functional class (by NYHA). The studies analyzed the changes in NYHA class, ejection fraction, peak oxygen consumption (VO2), the precursor of brain natriuretic peptide (NT-proBNP) level. Quality of life was assessed by the Minnesota questionnaire; the mortality rate was compared with that predicted by MAGGIC scale. CCM therapy had beneficial effect on the survival and quality of life in patients with CHF. However, more data is needed to assess long-term effects of the CCM therapy.