IMMUNOSUPPRESSIVE THERAPY FOR THE CONTROL OF LIFE-THREATENING VENTRICULAR ARRHYTHMIAS IN CHRONIC MYOCARDITIS

Chronic myocarditis predisposes to the occurrence of spontaneous ventr icular arrhythmias. It is not known if an immunosuppressive treatment - as a causal therapy - leads to arrhythmia suppression. In the presen t study, 12 patients (four female, eight male, mean age 53 +/- 15 year s) with a mean left-ventricular ejection fraction of 52 +/- 19 % were included. After exclusion of coronary macroangiopathy, the presence of chronic myocarditis was demonstrated by immunohistological evaluation of right-ventricular biopsies taking the number of specific lymphocyt es (CD 2-8), of activated macrophages and the degree of HLA-expression on interstitial and endothelial cells as a basis. Seven patients had a successful resuscitation due to ventricular fibrillation in their ca se history, three patients presented sustained monomorphic ventricular tachycardia and two syncopes with inducible tachyarrhythmias. As a '' conventional'' therapy ten patients received antiarrhythmic drugs and four patients an implantable cardioverter/defibrillator. After confirm ation of the diagnosis by a second biopsy after 3 months, all patients underwent an immunosuppressive therapy with methylprednisolone. The i nitial dose of 1 mg/kg body weight was reduced by 20 mg each every 2 w eeks, until a maintenance dosage of 8-12 mg/day was achieved. If the c ontrol study after 6 months still gave a positive result, a combined t herapy with azathioprine, 100-150 mg/day, was carried out for a furthe r 6 months. In nine patients (75 %), the control biopsy became negativ e, in three patients (25 %), the biopsy remained to be positive. In th e group presenting negative bioposies no tachyarrhythmia relapse occur red within a follow-up period of 49 +/- 13 months, while in the group with positive biopsies, relapses occurred in two of three patients. Co mplete suppression during EPS after therapy was achieved in 50 % of th e patients who were inducible before therapy. In addition to lymphocyt e infiltration, particularly HLA expression on endothelial and interst itial cells was significantly reduced; left-ventricular ejection fract ion was improved only in tendency, while left-ventricular filling pres sure decreased significantly. In summary, in patients with chronic myo carditis and malignant ventricular arrhythmias, a high-dose immunosupp ressive long-term therapy results in the significant reduction of infl ammatory infiltrations in about 75 % of the cases and, at the same tim e, in the effective suppression of arrhythmias.