Xinsuning capsule for the treatment of premature ventricualr contraction: a multicenter randomised clinical trial

BackgroundPremature ventricular contraction (PVC) is one of the most common cardiac disorders. Most of the antiarrhythmic chemical drugs (type I–IV) have important clinical effects, but none of them is satisfactory enough because of proarrhythmia and other side-effects. Xinsuning is a Chinese patent drug that has been commonly used in clinical practice in China and has potential advantages in treating arrhythmia. Findings from an experimental study in Oxford University showed that xinsuning could increase the effective refractory period, which suppressed tachyarrhythmias caused by re-entry mechanisms. This study aimed to assess the clinical effect of xinsuning for PVC.MethodsThis three-armed randomised clinical trial took place in 2014 in China (ChiCTR-TRC-14004180). Patients diagnosed with PVC were randomly assigned (2:2:1) to xinsuning (1·92 g in four capsules plus simulated mexiletine 100 mg in two capsules), mexiletine (simulated xinsuning 1·92 g plus mexiletine 100 mg), or placebo groups (simulated xinsuning 1·92 g and simulated mexiletine 100 mg). Each patient took the treatments three times daily for 4 weeks. The primary outcome was the change in the frequency of premature ventricular contractions detected by 24 h ambulatory electrocardiography.Findings861 patients from 39 hospitals were eligible for inclusion. 343 patients were assigned to the xinsuning group, 345 patients were assigned to the mexiletine group, and 173 patients were assigned to the placebo group. The mean reduction of the PVC frequency in the xinsuning, mexiletine, and placebo groups were 4604·67 (SD 6990·07), 4502·86 (5771·70), and 1512·47 (8311·14), respectively. The difference in PVC frequence between patients in the xinsuning and mexiletine groups versus placebo group was statistically significant (xinsuning vs placebo Z=6·2630, p<0·0001; mexiletine vs placebo Z=6·2856, p<0·0001). We detected no difference between the xinsuning and mexiletine group (Z=0·4806, p=0·6308).InterpretationXinsuning capsule is effective drug for PVC. Xinsuning can be used as a complementary or alternative therapy for PVC, especially for patients with contraindications of chemical drugs. This is a three-arms multicentre randomised clinical trial, with placebo and positive drugs control. Double-blind and double-simulation were used to reduce the performance bias. Patient's syndrome of traditional Chinese medicine was not considered as a factor for inclusion criteria and random allocation. This may weaken the effect of xinsuning. The interaction between xinsuning and mexiletine was not investigated.FundingShanxi Momentum Pharmaceutical Company.