Meta-analysis Of Effectiveness Of Cardiac Resynchronization Therapy In Patients With NYHA Class Ⅰ/Ⅱ Heart Failure

Objective To evaluate the effectiveness of cardiac resynchronization therapy(CRT) on patients with reduced ejection fraction(EF), prolonged QRS interval, and New York Heart Association (NYHA) functional class Ⅰ/Ⅱ heart failure(HF) by Meta-analysis. Methods Prospective randomized controlled trials of CRT in patients with New York Heart Association(NYHA) Class Ⅰ/Ⅱ heart failure were identified. Data regarding all-cause mortality, heart failure events, left ventricular(LV) volumes and ejection fraction,6-min walk distance (6MWT), improved NYHA functional class, complications were extracted and meta-analyzed by using Review Manager5.0software. Results Five randomized controlled studies met inclusion criteria, including4,317patients with NYHA functional class Ⅰ/Ⅱ HF.CRT significantly decreased all-cause mortality by19%[RR(relative risk)0.81,95%confidence interval (CI)0.67to0.79; Z=2.26, P=0.02], and HF hospitalization risk by31%[RR0.69,95%CI0.59to0.80;Z=4.94, P<0.00001]. CRT also reduced a significant LV reverse remodeling:[weighted mean difference (WMD)of LVEF4.82%,95%CI0.95to8.69;Z=2.44, P=0.01],[WMD of LVEDV-37.6ml,95%CI-40.24to-35.01; Z=28.20, P<0.00001],[WMD of LVESV-39.05ml,95%CI-41.61to-36.49; Z=29.92, P<0.00001],[WMD of LVEDVi-18.82ml/m2,95%CI-20.10to-17.53;Z=28.74, P<0.00001],[WMD of LVESVi-19.43ml/m2,95%CI-20.68to-18.19; Z=30.55, P<0.00001]. In addition, CRT improved NYHA functional class [RR1.37,95%CI1.13to1.66; Z=1.90, P=0.06] and6-min walk distance [WMD6.8m,95%CI4.61to8.98; Z=6.09, P<0.00001]. However, complications in patients with CRT increased by78%[RR1.78,95%CI1.46to2.18; Z=5.73, P<0.00001]. Conclusions This meta-analysis suggests that CRT could decrease all-cause mortality and the risk of heart failure hospitalization,reduce LV reverse remodeling and increase in6minutes walking distance among patients with reduced ejection fraction, prolonged QRS interval, and NYHA functional class Ⅰ/Ⅱ heart failure. However, there is no evidence of improvements in NYHA functional class showed in this study, which also reveals CRT could bring about high risk of complications.