An magnetic resonance imaging-pathology correlation case report of cardiac sarcoidosis mimicking arrhythmogenic biventricular cardiomyopathy.

Background: Cardiac sarcoidosis (CS) is a granulomatous disease that can manifest as conduction defects, ventricular arrhythmias, and heart failure. The diagnosis of CS is inherently difficult due to variable presentations; as such, endomyocardial biopsy is often required but lacks sensitivity due to patchy myocardial involvement. Moreover, the diagnostic criteria of CS and arrhythmogenic cardiomyopathy overlap, particularly in right-side dominant or biventricular presentations, which further complicates an already challenging differential diagnosis.

Case Summary: A 53-year-old man with no prior chronic medical conditions presented with ventricular tachycardia (VT) and heart failure with reduced ejection fraction. He was found to have biventricular cardiomyopathy and late gadolinium enhancement on cardiac magnetic resonance imaging, resulting in an initial diagnosis of arrhythmogenic cardiomyopathy. Implantable cardioverter-defibrillator was placed, but he was readmitted for recurrent VT 2 months later. Despite an aggressive VT therapy (combination of antiarrhythmic drugs, epicardial and endocardial ablation, and stellate ganglion block), he continued with refractory VT and developed cardiogenic shock. Extra-corporeal membrane oxygenation was initiated as a bridge to heart transplantation. Pathology of the explanted heart revealed the underlying disease to be CS.

Discussion: Cardiac sarcoidosis can mimic arrhythmogenic biventricular cardiomyopathy and may be difficult to distinguish by the proposed diagnostic criteria. High clinical suspicion and thorough investigation are necessary for an earlier diagnosis and initiation of treatment.