Monomorphic Ventricular Tachycardia and Mediastinal Adenopathy Due to Granulomatous Infiltration in Patients With Preserved Ventricular Function

Abstract

This report characterizes a syndrome of granulomatous infiltration presenting as sustained monomorphic ventricular tachycardia (SMVT) with mediastinal adenopathy in patients with preserved ventricular function. Unlike truly idiopathic ventricular tachycardia, SMVT due to granulomatous infiltration responds poorly to radiofrequency ablation and has a poor prognosis. Patients without obstructive coronary artery disease and with normal ventricular function presenting with SMVT other than posterior fascicular morphology were evaluated. Computed chest tomograms, cardiac magnetic resonance imaging, and 18-fluorodeoxyglucose positron emission tomographic scans ((18)FDG PET-CT) were performed. Significant lymph nodes were evaluated for tuberculosis and sarcoidosis. Initial treatment included antiarrhythmic drugs ± radiofrequency ablation. Additionally, patients with evidence of tuberculosis received anti-tuberculosis therapy; the rest were treated as sarcoidosis. Mediastinal adenopathy with mid-myocardial scar and/or focal myocardial inflammation was observed in 14 patients; lymph nodes revealed noncaseating granulomas in all. Evidence of tuberculosis was present in 79%. During follow-up (median duration 25 months), SMVT recurred despite initial treatment in 92%. Addition of disease-specific therapy abolished further recurrences in 64% of them. Decrease in SMVT correlated with resolution of myocardial inflammation on serial (18)FDG PET-CTs. Appropriate therapies occurred in 67% of patients receiving implantable cardioverter-defibrillators. A subset of patients with SMVT with preserved ventricular function has a syndrome of arrhythmogenic myocarditis with granulomatous mediastinal adenopathy due to myocardial tuberculosis or cardiac sarcoidosis. This entity is optimally managed with a combination of disease-specific therapy and antiarrhythmic measures.