Multi-Modality Imaging, Electrophysiological, Electroanatomical, and Histopathological Characterisation of Atrial Sarcoidosis Presenting with Sinus Node Dysfunction and Sinus Arrest

Abstract

Introduction: A 42-year-old man presented via the emergency department for recurrent dizziness. His background included well-controlled type 2 diabetes mellitus. Electrocardiogram revealed junctional bradycardia at 40 bpm with aberrantly conducted premature atrial complexes. Telemetry further demonstrated episodes of atrial fibrillation and symptomatic sinus pauses for up to 8 seconds. Transthoracic echocardiogram revealed a structurally normal heart; however, cardiac magnetic resonance imaging showed diffuse multichamber T2 hyperintensities and diffuse late gadolinium enhancement. This correlated with multichamber hypermetabolism on Fludeoxyglucose positron emission tomography computed tomography. Electrophysiology study revealed severe sinus node dysfunction with sinus node recovery times up to 2,834 ms with intact AV nodal and His-Purkinje conduction. Serum angiotensin-converting enzyme level was elevated at 96 U/L (20–70 U/L) and fine-needle aspiration biopsy of a hypermetabolic paratracheal lymph node showed a non–caseating granuloma, confirming the diagnosis of sarcoidosis with cardiac involvement.