Classic herbal formula Zhigancao Decoction for the treatment of premature ventricular contractions (PVCs): A systematic review of randomized controlled trials

Abstract

To systematically assess the current clinical evidence of Zhigancao (ZGC) Decoction for premature ventricular contractions (PVCs). PubMed, the Cochrane Center Controlled Trials Register, EMBASE, Chinese National Knowledge Infrastructure, Chinese Scientific Journal Database, and Wanfang Med Online Database were searched until June 2014. We included randomized clinical trials testing ZGC Decoction against anti-arrhythmic drugs, ZGC Decoction combined with anti-arrhythmic drugs versus anti-arrhythmic drugs alone. Study selection, data extraction, quality assessment, and data analyses were conducted according to the Cochrane standards. A meta-analysis of improving total effects and reducing number of ventricular premature beats was performed to evaluate the effects of ZGC Decoction on PVCs. A total of 25 studies (involving 2441 patients) were included. The methodological quality of the included trials was evaluated as generally low. The results of the meta-analysis showed that ZGC Decoction combined with anti-arrhythmic drugs had significant effect on improving total effects (RR: 1.30 [1.22, 1.38]; P<0.00001) and relieving number of ventricular premature beats (MD: -6.66 [-12.94, -0.37]; P=0.04) compared with anti-arrhythmic drugs alone. Our review showed that ZGC Decoction was more effective in improving total effects (RR: 1.22 [1.08, 1.37]; P=0.0009), compared with anti-arrhythmic drugs alone. 13 trials reported adverse events, while the others did not mention them, indicating that the safety of ZGC Decoction remains uncertain. ZGC Decoction appears to have beneficial effects on improvement of total effects, reduction of number of ventricular premature beats in participants with PVCs. However, further thorough investigation, large-scale, proper study designed, randomized trials of ZGC Decoction for PVCs will be required to justify the effects reported.