Diagnostic accuracy of cardiac magnetic resonance imaging for cardiac sarcoidosis in complete heart block patients implanted with magnetic resonance-conditional pacemaker

Background: Cardiac magnetic resonance (CMR) imaging has become the principal noninvasive imaging modality for the diagnosis of cardiac sarcoidosis (CS) patients. This study aimed to determine the diagnostic performance of CMR imaging for CS in new-onset complete heart block (CHB) patients implanted with magnetic resonance-conditional pacemaker (MRCP).

Methods: Fifty CHB patients implanted with MRCP were enrolled in this study. Clinical CS was diagnosed if there was a histological diagnosis of extra-cardiac sarcoidosis in patients with CHB based on the consensus statement; clinical CS was the reference standard. The diagnostic performance of CMR sequences, including cine magnetic resonance imaging (MRI), increased T2-weighted signal (T2WS), and late gadolinium enhancement (LGE), for clinical CS was investigated. We also compared the diagnostic performance of CMR sequences between the entire left ventricle (LV) and the basal septum, which involves the electrical pathway of atrioventricular conduction.

Results: In total, 8 of the 50 patients with CHB were confirmed to have extra-cardiac sarcoidosis and were diagnosed with clinical CS. The accuracy, sensitivity, and specificity of LGE in the basal septum and entire LV were 94%, 100%, and 93% and 80% (p = 0.023), 100% (p = 1.00), and 76% (p = 0.023), respectively. The accuracy, sensitivity, and specificity of increased T2WS and cine MRI in the basal septum were 94%, 75%, and 98% and 90%, 38%, and 100%, respectively. There was no statistical difference between the entire LV and the basal septum for the diagnostic performance of increased T2WS and cine MRI.

Conclusions: CMR can be a diagnostic tool for evaluating clinical CS in patients with CHB implanted with MRCP. LGE in the basal septum might provide the overall best diagnostic performance for clinical CS with CHB.