Heart Failure

Cardiac Sarcoidosis — Divergent Diagnostic Philosophies Between Japan and North America

• Authors: Cross-regional review group
• Journal / date: Journal of Cardiac Failure, 2026
• DOI / URL: 10.1016/j.cardfail.2026.04.019 | PMID 42114735
• Source basis: Abstract only
• Study type: Review
• Scope: Compares Japanese Circulation Society (JCS) vs US (HRS, NHLBI) diagnostic frameworks for cardiac sarcoidosis (CS)
• Key contrasts:
• JCS: earlier recognition; accepts "clinically diagnosed" CS based on imaging (FDG-PET, CMR) in patients with known systemic sarcoid — biopsy not required. Recognizes "clinically isolated CS" as a discrete entity.
• US: emphasizes specificity — histologic proof from any organ required for definitive diagnosis.
• Why it matters (clinical takeaway):
• Diagnostic threshold directly drives downstream decisions: when to start immunosuppression, when to place ICD for unexplained LV dysfunction or arrhythmia, when to refer for advanced therapies.
• In US practice, knowing the JCS approach helps when a patient with high pre-test probability (e.g., AV block + LV dysfunction + FDG-PET pattern) lacks tissue diagnosis — the JCS framework offers a defensible pathway for empiric management.
• Argues for international harmonization to allow trials and registries to enroll on a shared definition.
• Caveats / limitations: Narrative review.
• Referenced trials pulled forward: None.