Challenges in the diagnosis of cardiac sarcoidosis- an observational study from northern India

Abstract Background Cardiac involvement in sarcoidosis is associated with significant morbidity and mortality. Current diagnostic criteria for cardiac sarcoidosis (Heart Rhythm Society 2014 and Japanese Circulation Society 2017) mainly stress on proof of extracardiac involvement for diagnosis of cardiac sarcoidosis. However, isolated cardiac presentation without any extracardiac involvement is a common clinical scenario, posing a challenge in correct diagnosis. Purpose The current study was conducted to assess the challenges faced in diagnosing cardiac sarcoidosis. Methods This was a single-centre retrospective observational study, where we enrolled patients with a provisional diagnosis of cardiac sarcoidosis managed between January 2021 and December 2023 (3 years). The study included patients with primary cardiac manifestation suggestive of cardiac sarcoidosis (new onset ventricular arrhythmia, conduction disturbance, ventricular dysfunction/heart failure) and cardiac imaging (MRI/PET) showing patchy myocardial inflammation. Clinical details, investigations and details of treatment received were collected from the hospital database. After collecting all available clinical information, diagnostic criteria (HRS and Japanese guidelines) were applied to each enrolled patie Results The study included a total of 42 patients with provisional diagnosis of primary cardiac sarcoidosis. Ventricular tachycardia(20) was the most common cardiac manifestation, followed by heart failure(12) and complete heart block(10). Endomyocardial biopsy was performed in 11 patients, out of which only one patient showed evidence of granuloma in histopathology. CT chest detected mediastinal lymphadenopathy in 20/42(47%) patients, out of which only nine patients showed sarcoid granuloma in histopathology. Two patients had skin lesions, and histopathology revealed granuloma suggestive of sarcoidosis. After relevant investigations, both diagnostic criteria were applied to all patients. Only one patient had evidence of granulomatous inflammation in an endomyocardial biopsy, meeting the histological diagnosis of both criteria. According to HRS 2014 criteria, 30/42(71%) did not meet any diagnosis as there was no histologic evidence of extracardiac sarcoidosis. According to Japanese Circulation Society guidelines, diagnosis of cardiac sarcoidosis was uncertain in 15/42(35%) patients. Four patients (9.5 %) included in the study had some evidence of extracardiac focus of TB and were treated with both anti-tubercular therapy and steroids. Conclusion The present study demonstrates a high proportion of patients with an isolated cardiac presentation with imaging evidence (Cardiac MRI/PET) without any evidence of extracardiac organ involvement posing a challenge to diagnosis. With the advancement of cardiac imaging, more such cases getting diagnosed provisionally as sarcoidosis and guidelines should consider reclassification.Table 1 Table 2