We examined 114 patients who were diagnosed with inflammatory heart disease without proof of viral infection based on immunohistochemical methods or PCR using tissue from endomyocardial biopsies. These patients were examined before and after immunoglobulin therapy. Diagnosis of inflammatory heart disease is defined by: 14 lymphocytes / mm2 in endomyocardial biopsy tissue and / or a positive histopathological result according to the Dallas criteria. Patients were treated on day one and on day three with Pentaglobin® at 10 ml/day/kg bodyweight. Within six months of therapy initiation, 45 patients (40 %) were rebiopsied to determine the effectiveness of the therapy. We compared the following parameters before and after therapy: left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVEDD), shortening fraction (SF) or the left ventricular end-diastolic volume index (LVEDVI) using cardiac catheterization where a second heart catheter examination was available. Furthermore, we evaluated respective ECG, treadmill tests and clinical parameters according to the NYHA classification and epidemiological data (age, gender, heart failure medication), before and after therapy. After Pentaglobin® therapy, all patients demonstrated a significant clinical improvement according to the NYHA classification and an improved LVEF and LVEDD. Seventy-one percent of rebiopsied patients exhibited no evidence of residual inflammatory disease. We report a conspicuous reduction of the inflammatory reaction as well as an improvement in cardiac function in patients with inflammatory heart disease after immunoglobulin therapy. We found a significant improvement of LVEDD, LVEF and SF in patients with a reduced LVEF (<50%), a large LVEDD and a NYHA classification III or IV at the beginning of the immunoglobulin therapy. In summary our results show that an immunoglobulin therapy is able to improve the cardiac function and to assuage the aliments of the patients. Beyond, it seems that the immunoglobulin treatment has a positive effect on the elimination of the myocardial inflammation. It becomes clear that only in resuming controlled clinical studies it can be clarified whether the good results of our investigation can be reproduced.