Cardiovascular magnetic resonance (CMR) imaging is being increasingly used to help identify patients with cardiac sarcoidosis (CS). Whereas ventricular arrhythmias have been well studied in this population, atrial arrhythmias have not been thoroughly investigated. We sought to better characterize the arrhythmia burden of a cohort of patients diagnosed with CS by CMR imaging. Patients with biopsy-proven extracardiac sarcoidosis were referred to the University of Chicago for evaluation of the presence of CS. CMR imaging was used to categorize the patients into 2 groups; those with and those without late gadolinium enhancement (LGE) for comparison of arrhythmic events. Arrhythmic evaluation included Holter monitor, event recorder, electrophysiology testing, or implantable cardioverter-defibrillator (ICD) interrogation; 192 consecutive patients were evaluated with CMR imaging, 57 of whom did not have ambulatory monitoring results and thus were excluded. LGE was present in 44 patients. Atrial arrhythmias were documented in 16 patients (36%) with myocardial LGE and in 11 patients (12%) without myocardial LGE (p = 0.002). Ventricular arrhythmias were documented in 27% of patients with myocardial LGE and 2.2% of LGE-negative patients (p = 0.00076). Of 26 LGE-positive patients with ICDs, 8 (30.8%) received therapies, 3 (11.5%) of which were inappropriate for atrial arrhythmias. In conclusion, atrial arrhythmias were documented more frequently than ventricular arrhythmias in patients with sarcoidosis with cardiac involvement and were 3 times more prevalent than in patients with sarcoidosis without cardiac involvement. Risk-benefit assessment of anticoagulation for primary prevention of stroke should be performed for patients with CS. In patients receiving implantable defibrillators, programming to minimize inappropriate ICD shocks for atrial arrhythmias must be considered.
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