Screening for cardiac sarcoidosis: diagnostic approach and long-term follow-up in a tertiary centre

Background: Cardiac sarcoidosis (CS) is associated with poor prognosis, making early diagnosis and treatment important. This study evaluated the results of a diagnostic approach in patients with known sarcoidosis and suspected cardiac involvement in a tertiary centre and their long-term outcomes.

Methods: We included 180 patients with sarcoidosis and a clinical suspicion of CS. In addition to an electrocardiogram (ECG)/transthoracic echocardiogram (TTE), cardiovascular magnetic resonance imaging (CMR) and positron emission tomography (PET) were performed in 66% and 37% of the patients, respectively. The diagnosis of CS was based on the Heart Rhythm Society criteria. Follow-up was performed, and a composite endpoint of sustained ventricular tachycardia, ventricular fibrillation, aborted sudden cardiac death, heart failure hospitalisation, heart transplantation or cardiac death was used for the survival analysis.

Results: Symptoms were present in 87% of the patients, and ECG/TTE abnormalities were found in 92/180 patients (51%). Using CMR and/or PET, 31/92 patients (34%) were diagnosed with CS. In 15 patients, an alternative diagnosis was found. CS was diagnosed in 11/88 patients (13%) without ECG/TTE abnormalities. During a median follow-up time of 4.4 years (interquartile range: 2.3-6.8), 11 composite endpoints occurred, more frequently in CS patients than in sarcoidosis patients without cardiac involvement (p < 0.001). Patients with ECG/TTE abnormalities at baseline had worse outcomes than those without abnormalities (p = 0.019).

Conclusion: CS was diagnosed in 23% of the referred sarcoidosis patients. ECG/TTE were of limited diagnostic value for screening for CS but seemed to have important prognostic value as patients with normal ECG/TTE results who did meet the diagnostic CS criteria had a very good prognosis. CMR/PET provided a good diagnostic yield and identified other cardiac diseases.