73-05: Focal Hypermetabolic Left Ventricular Cardiomyopathy: An Underdiagnosed Life-threatening Arrhythmogenic Disease

Abstract

Introduction: Cardiac sarcoidosis (CS) may be misinterpreted as an ARVC. The prevalence of isolated CS in pts referred for the ablation of ventricular arrhythmias (VAs) remains undetermined. Method: Pts with VAs addressed for ablation underwent a comprehensive work-up starting with a coronary angiography (CA) and CMR. Those displaying normal CA but delayed enhancement (DE) within the left ventricle (LV) underwent a FDG-PET. Pts exhibiting focal hypermetabolic LV activity had a pulmonary and blood screening (autoantibodies, TB spot, sedimentation rate, CRP, plasmatic conversion enzyme activity). Results: Over a 2-y period, 59 pts were addressed for symptomatic VAs ablation. Of these, 14 pts (24%, 56±13 yo, 10 males, LVEF 44±10%) displaying a focal hypermetabolic LV activity at FDG-PET underwent the comprehensive work-up. The immunologic, infectious and plasmatic screenings were within the normal limits, except for a positive TB-spot in 2 cases. LV biopsies (n=10) were abnormal in only 4 cases (29%); one showing lymphocytes and the others showing fibrosis, none with granuloma. The figure below shows an example of septal and lateral DE at CMR (A) and focal hypermetabolic LV activity at FDG-PET (B). Although unproven, isolated CS was suspected, which was treated in 9 pts (Prednisone, then Methotrexate sc). Focal hypermetabolic LV activity was erased in 5/ 9 (67%) and strongly reduced in 3/9 (33%) pts (C). Two pts required treatment of TB before immunosuppression. Conclusion: In pts with symptomatic complex VAs, a comprehensive work-up based on CMR and FDG-PET identified a high proportion of focal hypermetabolic LV activity suggestive of isolated CS. There were no blood markers, but immunosuppressive therapy strongly reduced the hypermetabolic Activity (Figure Presented).