The safety and efficacy of cardiac contractility modulation in heart failure A meta-analysis of clinical trials

Cardiac contractility modulation (CCM) has developed as a promising treatment device for heart failure (HF). This meta-analysis aimed at systematically reviewing the latest available published trials to provide evidence on the safety and efficacy of CCM in patients with HF. We searched the Cochrane Central Resister of Controlled Trials, PubMed, and EMBASE in May 2016 to identify eligible clinical trials comparing CCM with sham treatment or with usual care. All-cause mortality, all-cause hospitalization, and serious cardiopulmonary adverse effects were considered to be the primary outcomes of interest in evaluating the safety of CCM for patients with HF. Peak oxygen consumption and 6aEuromin walk tests were performed as the second outcomes of interest to assess efficacy. Risk ratio (RR), standard mean difference (SMD), and 95% confidence intervals (CIs) were calculated. Four studies enrolling 723 participants were included. Compared with the control arm, CCM did not significantly improve all-cause mortality or all-cause hospitalizations. No differences were observed for adverse effects of CCM, possibly due to the low number of studies. By contrast, CCM significantly improved peak oxygen consumption (standard mean difference 0.233, 95% CI, 0.065-0.401 ml/kg/min, p = 0.006) and the 6aEuromin walk test distance (standard mean difference 0.924, 95% CI, 0.001-0.334 m, p = 0.049). In our meta-analysis of published clinic trials we found that CCM did not lower the risk of severe cardiovascular adverse events; however, it was associated with remarkable improvements in functional cardiopulmonary capacity. Therefore, CCM may serve as an alternative option for patients with advanced HF.