Acute myocarditis is defined as inflammation of the myocardium, leading to the sudden onset of heart failure, arrhythmia, fulminant hemodynamic collapse and sudden mortality [1]. They may lead to dilated cardiomyopathy (DCM) and cardiac dysfunction, with serious and lethal consequences. This retrospective study was performed to evaluate the effect of intravenous immunoglobulin (IVIG) on the cardiac function and cardiac rhythm of children with acute myocarditis and/or early DCM.

The patients were divided into IVIG therapy and non- IVIG therapy (control) groups. Data analysis of laboratory tests including blood levels of myocardial enzymes, troponin, and C reactive protein; other investigations including electrocardiography, chest X-ray and echocardiography were performed prior to and following treatment. Gender, age, cardiac function classification, parameters of echocardiography, blood test data and incidence of complications were compared between the two groups. Echocardiography data was analyzed for by standard methodology. Left ventricular ejection fraction (LVEF), diameter of the left atrium (LA), left ventricular end diastolic diameter (LVEDD), left ventricular systolic diameter (LVSD), diameter of the right atrium (RA) and diameter of the right ventricle (RV) were analyzed. The recovery of left ventricular function was assessed in hospital and post-treatment at 3 and 6 months. IVIG was administered at a dose of 1 gm/kg per day for two days. Other conventional therapies were administered as required in both groups. The primary outcome was survival. Secondary outcomes measures were improve-ment in LVEF and LVEDD on echocardiography; and incidence of fatal cardiac arrythmias. All statistical analyses were performed with the Statistical Package for Social Sciences version 16.0 (SPSS Inc., Chicago, IL, USA).

A total of 35 children were initially eligible for the study; however, 7 were excluded due to insufficient clinical data/non comparable factors. Twenty-eight children were ultimately included. Of these, 12 patients, (7 males) had received treatment with IVIG (1gm/kg per day) for two days, while the remaining 16 patients (9 males) had not received IVIG therapy. At baseline, children of the two groups did not differ significantly with regard to the echocardiographic data of left ventricular function i.e. LVEF and LVEDD. At both three months and six months post-treatment, the mean LVEF and LVDD in the IVIG group was significantly better than control group (P=0.003). The LVEF of both groups had improved significantly at 6 months; however, children treated with IVIG had a significantly higher LVEF than those without IVIG. The episodes of ventricular tachycardia/fibrillation and atrioventricular block were reduced significantly in the IVIG group. There were two mortalities in the IVIG therapy group and seven in the non IVIG therapy group (P=0.032).

Previous studies have indicated the therapeutic effects of the high dose IVIG in acute myocarditis. [2-7]. High dose IVIG is commonly used at dosage of 1gm/kg/day for 2 days [5,8]. However, evidence from Cochrane collaboration review of 2010, based on one trial did not support the use of IVIG for the management of adults with presumed viral myocarditis, and observed that there are no randomized pediatric trials [8]. A randomized controlled trial (RCT) suggested that IVIG did not augment the improvement in LVEF for 62 patients with recent onset dilated cardiomyopathy [9]. We observed that IVIG therapy improved the outcome in such patients. The retrospective nature of the study, no comparison of baseline clinical data of patients, and non-availability of reasons for starting IVIG were the shortcoming of this study.

In conclusion, this study suggests that IVIG for the treatment of acute myocarditis and/or early dilated cardiomyopathy is associated with improved recovery of left ventricular function and a reduction in the episodes of fulminant arrhythmias.

Contributors: ANP, SC: were responsible for the clinical work; ANP: compiled the data, statistical analysis and drafted the manuscript. He will act as guarantor.

Funding: None; Competing interests: None stated.

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