Refractory ventricular tachycardia secondary to cardiac sarcoid: Electrophysiologic characteristics, mapping, and ablation

Abstract

Cardiac sarcoidosis is a recognized cause of ventricular tachycardia (VT) and sudden death that has not been well studied. The purpose of this study was to describe the clinical characteristics of a consecutive series of eight patients with recurrent monomorphic VT due to cardiac sarcoidosis and to define the electrophysiologic characteristics of the VT and its electrophysiologic substrate. Of 98 patents with nonischemic cardiomyopathy and VT referred for ablation over a 7-year period, sarcoid was the etiology in 8%. Mean age was 42 +/- 8 years, and all but one patient had a reduced left ventricular ejection fraction (mean 34% +/- 15%). VT was the initial manifestation of sarcoid disease in 5 of 8 cases based on retrospective analysis. All patients had not responded to therapy with multiple antiarrhythmic drugs (mean 2.5 +/- 1). Cardiac biopsy initially was negative in 3 of 7 patients, and in 2 patients the diagnosis was not made until posttransplant examination of the heart. Two patients (25%) had a previous presumptive diagnosis of arrhythmogenic right ventricular dysplasia. Electrophysiologic study revealed evidence of scar-related reentry with multiple monomorphic VTs induced (4 +/- 2 VTs per patient) with both right bundle branch block and left bundle branch block QRS configurations. Areas of low-voltage scar were present in the right ventricle in all 8 of 8 patients, in the left ventricle in 5 (63%) of 8 patients, and in the epicardium in 2 patients undergoing epicardial mapping. Ablation abolished one or more VTs in 6 (75%) of 8 patients, but other VTs remained inducible in all but one patient. Postablation, some form of sustained VT recurred in 6 of 8 patients within 6 months. However, at longer follow-up (range 6 months to 7 years), 4 of 8 patients currently are free of VT with antiarrhythmic drugs and immunosuppression. Cardiac transplantation eventually was required in 5 of 8 patients because of either recurrent VT (n = 4) or heart failure (n = 1). Sarcoid is an important diagnostic consideration in scar-related VT. Sarcoid can be misdiagnosed as idiopathic or arrhythmogenic right ventricular cardiomyopathy. Arrhythmia control can be difficult, although ablation can be helpful in some patients.