Diagnosis, treatment, and outcome of giant-cell myocarditis in the era of combined immunosuppression.

BACKGROUND

Giant-cell myocarditis often escapes diagnosis until autopsy or transplantation and has defied proper treatment trials for its rarity and deadly behavior. Current therapy rests on multiple-drug immunosuppression but its prognostic influence remains poorly known. We set out to analyze (1) our experience in diagnosing giant-cell myocarditis and (2) the outcome of patients on combined immunosuppression.

METHODS AND RESULTS

We reviewed the histories, diagnostic procedures, details of treatment, and outcome of 32 consecutive patients with histologically verified giant-cell myocarditis treated in our hospital since 1991. Twenty-six patients (81%) were diagnosed by endomyocardial or surgical biopsies and 6 at autopsy or post-transplantation. Twenty-eight (88%) patients underwent endomyocardial biopsy. The sensitivity of transvenous endomyocardial biopsy increased from 68% (19/28 patients) to 93% (26/28) after up to 2 repeat procedures. The 26 biopsy-diagnosed patients were treated with combined immunosuppression (2-4 drugs) including cyclosporine in 20 patients. The Kaplan-Meier estimates of transplant-free survival from symptom onset were 69% at 1 year, 58% at 2 years, and 52% at 5 years. Of the transplant-free survivors, 10/17 (59%) experienced sustained ventricular tachyarrhythmias during follow-up and 3 received intracardiac defibrillator shocks for ventricular tachycardia or fibrillation.

CONCLUSIONS

Repeat endomyocardial biopsies are frequently needed to diagnose giant-cell myocarditis. On contemporary immunosuppession, two thirds of patients reach a partial clinical remission characterized by freedom from severe heart failure and need of transplantation but continuing proneness to ventricular tachyarrhythmias.