The efficacy and safety of cardiac contractility modulation in patients with nonischemic cardiomyopathy: Chinese experience

Abstract

Background: Cardiac contractility modulation (CCM) has been used in patients with heart failure and normal QRS duration to improve exercise tolerance and quality of life. The safety and efficacy of CCM have been previously tested in moderate to severe heart failure patients with various etiologies in the western population. However, limited data are available on the safety and efficacy of CCM in Chinese patients with dilated cardiomyopathy and heart failure. Methods: Eight patients with dilated cardiomyopathy were prospectively enrolled to receive CCM implants from 5 hospitals in China. All patients had the New York Heart Association (NYHA) functional class III and IV heart failure, with left ventricular ejection fraction (LVEF) ≤35%, and QRS ≤ 120 ms. All patients were followed up at the 3rd and 6th month. Evaluation included the NYHA functional class, 6-min hall walk test (6MHW), Minnesota Living with Heart Failure (MLWHF) Questionnaire, and CCM parameters. Results: CCM was successfully implanted in all eight patients (50 ± 11 years, 6 men), and no device-related complications were observed in all patients at 3- and 6-month follow-up besides one patient voluntarily received heart transplantation at the 2nd month after CCM implantation and died from intracerebral hemorrhage during the perioperative period. Compared with baseline, the NYHA functional class (ΔNYHA: −1.0–−3.0, P= 0.016), the MLWHF quality of life scores (ΔMLWHF: −21.1 ± 17.5, P= 0.019), and 6MHW (Δ6MHW: 207.4 ± 202.5 m, P= 0.035) were significantly improved at 3-month follow-up. No significant change was observed in LVEF (ΔLVEF: −0.5%, 95% CI: −2.0%–12%, P= 0.813). All of these evaluations at 6-month follow-up were similar to those observed at 3-month, and no further improvement were observed from 3- to 6-month follow-up in the NYHA functional class (ΔNYHA 0; 0–1.0, P= 0.999), 6MHW (Δ6MHW: 39.2 ± 70.4 m, P= 0.231), MLWHF quality of life score (ΔMLWHF: 2.7 ± 3.9, P= 0.158), and LVEF (ΔLVEF: 2.0%, 95% CI: −2.0%–7.0%, P= 0.313). Conclusions: CCM might be a new choice of device treatment for Chinese patients with nonischemic cardiomyopathy and heart failure if they have normal QRS duration.