Successful treatment of life-threatening giant cell myocarditis in a patient with Brugada syndrome, controlled through dual ablation procedures and immunosuppressive therapy

A 50-year-old man who had been followed up with asymptomatic Brugada syndrome (Panel A1, baseline, 4-year-prior electrocardiogram) experienced prominent ST elevation in V1–2 (Panel A2) and recurrent ventricular fibrillation (VF, Panel A3). Cardiac echocardiography and coronary angiography did not show any abnormality, but VF was uncontrollable, leading to his connection with percutaneous cardiopulmonary support. He was transferred to our hospital to control VF. We established epicardial access and performed ablation to cover the late activation zone with fractionated potentials in the right ventricular outflow tract (Panel B). Although the VF storm was controlled, his left ventricular (LV) systolic function deteriorated gradually to an ejection fraction (EF) of 25%, and prominent myocardial oedema was observed in the LV wall (Panel C and Supplementary data online, Movies S1 and S2). Myocardial biopsy indicated myocarditis with infiltration of inflammatory cells, including giant cells (Panel D, white arrow). We diagnosed giant cell myocarditis with VF and severe LV dysfunction. Therefore, we started steroid pulse therapy, but another VF storm recurred, leading to a second ablation procedure. Cryoenergy ablation to the moderator band in the right ventricle (Panels E and F and Supplementary data online, Movie S3) successfully eliminated the ventricular premature contraction that triggered VF, as radiofrequency ablation to the same site readily and repeatedly induced VF during energy delivery. We started the administration of cyclosporin A after additional steroid pulse therapy, and echocardiography showed the patient's cardiac function fully recovered at discharge (LV ejection fraction 60%) (Panel G and Supplementary data online, Movie S4). This life-threatening myocarditis developed in a patient with Brugada syndrome underscores the usefulness of two rescue ablation procedures alongside appropriate immunosuppressive therapy.