Background Herbal medicines are being used for treating viral diseases including viral myocarditis, and many controlled trials have been done to investigate their efficacy. Objectives To assess the effects of herbal medicines on clinical and indirect outcomes in patients with viral myocarditis. Search strategy We searched the Cochrane Central Register of Controlled Trials(CENTRAL) in The Cochrane Library Issue 3, 2009, MEDLINE (January 1966 - July 2009), EMBASE(January 1998 - July 2009), Chinese Biomedical Database(1979 - 2009), China National Knowledge Infrastructure(1979 - 2009), Chinese VIP Information(1989 - 2009), Chinese Academic Conference Papers Database and Chinese Dissertation Database (1980 - 2009), AMED(1985 - 2009), LILACS accessed in July 2009 and the trials register of the Cochrane Complementary Medicine Field. We handsearched Chinese journals and conference proceedings. No language restrictions were applied. Selection criteria Randomised controlled trials of herbal medicines (with a minimum of seven days treatment duration) compared with placebo, no intervention, or conventional interventions were included. Trials of herbal medicine plus conventional drug versus drug alone were also included. Only trials that reported adequate description of allocation sequence generation were included. Data collection and analysis Two review authors independently extracted data and evaluated trial quality. Adverse effects information was collected from the trials. Main results Fourteen randomised trials involving 1463 people were included. All trials were conducted and published in China. Quality of the trials was assessed to be low. No trial had diagnosis of viral myocarditis confirmed histologically, and only a few trials attempted to establish viral aetiology. Nine different herbal medicines were tested in the included trials. The trials reported electrocardiogram results, level of myocardial enzymes, cardiac function, symptoms, and adverse effects. Astragalus membranaceus (either as an injection or granules) showed significant positive effects in symptom improvement, normalisation of electrocardiogram results, CPK levels, and cardiac function. Shengmai injection also showed significant effects in symptom improvement. Shengmai decoction triggered significant improvement in quality of life measured by SF-36. No serious adverse effects were reported. Authors' conclusions Some herbal medicines may lead to improvement of symptoms, ventricular premature beat, electrocardiogram, level of myocardial enzymes, and cardiac function in viral myocarditis. However, interpretation of these findings should be taken with care due to the low methodological quality, small sample size, and limited number of trials on individual herbs. Further robust trials are needed to explore the use of herbal medicines in viral myocarditis.
