Cardiac contractility modulation was safe and feasible, significantly improving ejection fraction from 22.7% to 37% (P=0.004) and NYHA class from 3 to 1.5 (P<0.001).
Does cardiac contractility modulation improve safety, feasibility, and clinical outcomes in patients with drug-resistant systolic heart failure?
Cardiac contractility modulation appears safe and feasible in patients with severe heart failure, with preliminary evidence of improved systolic function and functional status.
INTRODUCTION: Conventional electrical therapies for heart failure (HF) encompass defibrillation and ventricular resynchronization for patients at high risk for lethal arrhythmias and/or with inhomogeneous ventricular contraction. Cardiac contractility modulation (CCM) by means of nonexcitatory electrical currents delivered during the action potential plateau has been shown to acutely enhance systolic function in humans with HF. The aim of this multicenter study was to assess the chronic safety and preliminary efficacy of an implantable device delivering this novel form of electrical therapy. METHODS AND RESULTS: Thirteen patients with drug-resistant HF (New York Heart Association NYHA class III) were consecutively implanted with a device (OPTIMIZER II) delivering CCM biphasic square-wave pulses (20 ms, 5.8-7.7 V, 30 ms after detection of local activation) through two right ventricular leads screwed into the right aspect of the interventricular septum. CCM signals were delivered 3 hours daily over 8 weeks (3-hour phase) and 7 hours daily over the next 24 weeks (7-hour phase). Safety and feasibility of this novel therapy were regarded as primary endpoints. Preliminary clinical efficacy, -as expressed by changes in ejection fraction (EF), NYHA class, 6-minute walking test (6-MWT), peak O(2) uptake (peak VO(2)), and Minnesota Living with HF Questionnaire (MLWHFQ), was assessed at baseline and at the end of each phase. At the end of follow-up (8.8 +/- 0.2 months), all patients were alive, without heart transplantation or need for left ventricular assist device. Serial 24-hour Holter analysis revealed no proarrhythmic effect. No devices malfunctioned or failed for any reason other than end-of-battery life. Throughout the two study phases, EF improved from 22.7 +/- 7% to 28.7 +/- 7% and 37 +/- 13% (P = 0.004), 6-MWT from 418 +/- 99 m to 477 +/- 96 m and 510 +/- 107 m (P = 0.002), MLWHFQ from 36 +/- 21 to 18 +/- 12 and 7 +/- 6 (P = 0.002), peak VO(2) from 13.7 +/- 1.1 to 14.9 +/- 1.9 to 16.2 +/- 2.4 (P = 0.037), and NYHA class from 3 to 1.8 +/- 0.4 to 1.5 +/- 0.7 (P < 0.001). CONCLUSION: CCM therapy appears to be safe and feasible. Proarrhythmic effects of this novel therapy seem unlikely. Preliminary data indicate that CCM gradually and significantly improves systolic performance, symptoms, and functional status. CCM therapy for 7 hours per day is associated with greater dispersion near the mean, emphasizing the need to individually tailor CCM delivery duration. The technique appears to be attractive as an additive treatment for severe HF. Controlled randomized studies are needed to validate this novel concept.
Pappone et al. (Thu,) conducted a other in Drug-resistant systolic heart failure (n=13). Cardiac contractility modulation (OPTIMIZER II) was evaluated on Safety and feasibility. Cardiac contractility modulation was safe and feasible, significantly improving ejection fraction from 22.7% to 37% (P=0.004) and NYHA class from 3 to 1.5 (P<0.001).