Background Sarcoidosis is an inflammatory granulomatous disease that can affect several organs. Cardiac involvement is increasingly prevalent. However, characteristics of patients who present de novo with cardiac sarcoidosis (CS) compared to those diagnosed with CS after prior extracardiac sarcoidosis (ECS) diagnosis have not been studied. Methods : A retrospective cohort of 253 CS patients from 2000-2020 at an urban, quaternary medical center was studied. Medical records were reviewed for initial CS presentation, management, and outcomes. Differences (two sample t-test, chi-squared test, or Fisher's exact test) between de novo CS and prior ECS groups were analyzed. Results : There were 124 (49%) de novo CS patients and 129 (51%) with prior ECS at time of CS diagnosis (Table). De novo CS patients were more likely to meet Heart Rhythm Society definite CS criteria (P<0.001) and were diagnosed and started immunosuppression for CS at a younger age (p=0.001 and p=0.003, respectively). De novo CS patients had a more advanced cardiac presentation at CS diagnosis, with lower left ventricular ejection fraction (LVEF) (p<0.001), more frequent ventricular tachycardia/fibrillation (p<0.001), heart failure (p=0.052), reduced LVEF<50% (p=0.004), and complete heart block (p=0.001). As for treatment, de novo CS patients received prednisone at a higher frequency (p<0.001) and dose (p=0.011) compared to patients with prior ECS. Steroid sparing agent (SSA) frequency was similar with mycophenolate mofetil used more commonly among de novo CS patients. During follow-up, new VT, VT ablation, LVAD implantation, and heart transplantation were more common in the de novo CS group. LVEF recovery was less common in this group while mortality was similar. Conclusions : Patients diagnosed with de novo CS were younger, with more advanced cardiac presentation and worse clinical outcomes when compared to those presenting with CS after known ECS. These findings highlight the importance of upfront consideration of CS as a cause of unexplained heart block, arrhythmia, or cardiomyopathy to ensure timely treatment and prevention of advanced heart failure. One cannot wait for a diagnosis of ECS to consider CS. Sarcoidosis is an inflammatory granulomatous disease that can affect several organs. Cardiac involvement is increasingly prevalent. However, characteristics of patients who present de novo with cardiac sarcoidosis (CS) compared to those diagnosed with CS after prior extracardiac sarcoidosis (ECS) diagnosis have not been studied. : A retrospective cohort of 253 CS patients from 2000-2020 at an urban, quaternary medical center was studied. Medical records were reviewed for initial CS presentation, management, and outcomes. Differences (two sample t-test, chi-squared test, or Fisher's exact test) between de novo CS and prior ECS groups were analyzed. : There were 124 (49%) de novo CS patients and 129 (51%) with prior ECS at time of CS diagnosis (Table). De novo CS patients were more likely to meet Heart Rhythm Society definite CS criteria (P<0.001) and were diagnosed and started immunosuppression for CS at a younger age (p=0.001 and p=0.003, respectively). De novo CS patients had a more advanced cardiac presentation at CS diagnosis, with lower left ventricular ejection fraction (LVEF) (p<0.001), more frequent ventricular tachycardia/fibrillation (p<0.001), heart failure (p=0.052), reduced LVEF<50% (p=0.004), and complete heart block (p=0.001). As for treatment, de novo CS patients received prednisone at a higher frequency (p<0.001) and dose (p=0.011) compared to patients with prior ECS. Steroid sparing agent (SSA) frequency was similar with mycophenolate mofetil used more commonly among de novo CS patients. During follow-up, new VT, VT ablation, LVAD implantation, and heart transplantation were more common in the de novo CS group. LVEF recovery was less common in this group while mortality was similar. : Patients diagnosed with de novo CS were younger, with more advanced cardiac presentation and worse clinical outcomes when compared to those presenting with CS after known ECS. These findings highlight the importance of upfront consideration of CS as a cause of unexplained heart block, arrhythmia, or cardiomyopathy to ensure timely treatment and prevention of advanced heart failure. One cannot wait for a diagnosis of ECS to consider CS.