A Comparative Analysis of Cardiac Amyloidosis and Cardiac Sarcoidosis: A Single-Center Experience

Background/Objectives: Cardiac amyloidosis (CA) and cardiac sarcoidosis (CS) are two distinct infiltrative cardiomyopathies that can present with overlapping clinical features, including heart failure and arrhythmias. However, they arise from fundamentally different pathophysiological mechanisms: amyloid protein deposition in CA versus granulomatous inflammation in CS, resulting in divergent imaging patterns, clinical trajectories, and treatment strategies. This study aimed to compare the clinical presentations, imaging characteristics, and outcomes of patients with CA and CS to identify key differentiating factors that can improve diagnostic precision and guide therapy. Methods: This single-center, retrospective, cross-sectional study analyzed electronic medical records of patients diagnosed with CA or CS within the Mount Sinai Morningside system until October 2023. Patients were identified using diagnostic codes and confirmed by histology or disease-specific imaging criteria. Clinical data, transthoracic echocardiography (TTE), cardiac magnetic resonance (CMR) imaging, pyrophosphate scintigraphy (PYP), and fluorodeoxyglucose positron emission tomography (FDG-PET) findings were collected. Statistical comparisons between groups were performed using chi-square tests and independent t-tests, with p< 0.05 considered statistically significant. Results: The study included 216 patients (125 CA, 91 CS). CA patients were older (78.2 vs. 62.0 years, p = 0.01), had greater interventricular septal thickness (1.57 vs. 1.10 cm, p = 0.01), and exhibited diffuse late gadolinium enhancement (LGE) and elevated extra-cellular volume (ECV) on CMR. CS patients had higher rates of ventricular tachycardia (53.3% vs. 10.7%, p = 0.01), increased myocardial fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET) (90%), and more frequent implantable cardioverter-defibrillator (ICD) placement (66.3% vs. 13.0%, p = 0.01). Mortality was higher in CA (18.7% vs. 5.4%, p = 0.01). Conclusions: CA and CS demonstrate distinct imaging profiles, arrhythmic risks, and treatment patterns. Early differentiation using advanced imaging is crucial for implementing disease-modifying therapies in CA and for immunosuppression and ICD implantation in CS, thereby improving patient outcomes.