Long-term risk of recurrence, morbidity and mortality in giant cell myocarditis.

Giant cell myocarditis (GCM) is a rare disorder in which survival beyond 1 year without heart transplantation is uncommon. Long-term follow-up data on those with such survival are lacking. Twenty-six patients with biopsy-proved GCM who survived for >1 year without heart transplantation were identified from a multicenter GCM registry. The incidence of death, transplantation, ventricular assist device placement, and histologically proved disease recurrence was ascertained retrospectively. The rates of recurrent heart failure, ventricular arrhythmias, renal failure, and infectious complications were calculated. The mean age of the cohort was 54.6 ± 13.9 years (65% women). The mean follow-up duration was 5.5 years starting 1 year after diagnosis. There were 3 deaths (12%), 5 heart transplantations (19%), and 1 ventricular assist device placement (4%). Three histologically confirmed recurrences of GCM (12%) occurred between 1.5 and 8 years after diagnosis. Thirteen of 26 patients experienced a total of 30 heart failure episodes ≥1 year after initial diagnosis. There were 23 episodes of elevated creatinine in 12 patients, 41 infectious events in 13 patients, and 19 episodes of ventricular arrhythmias in 6 patients with a total of 144 years of follow-up. Starting 1 year after GCM diagnosis, the combined rate of death, transplantation, ventricular assist device placement, and GCM recurrence was 47% at 5 years. In conclusion, the risk for GCM recurrence continues to ≥8 years after diagnosis.