ARF is an immune-mediated sequela of untreated strep pharyngitis and a must-know topic for USMLE Step 1.

🔬 Key Concepts:

• J♥NES criteria – Major clinical features you can’t forget

• Type II hypersensitivity (molecular mimicry)

• Mitral valve involvement: regurgitation early, stenosis later

• Penicillin for treatment and prophylaxis

🧠 Memorize the criteria, recognize the cardiac complications, and understand the immune mechanism behind it all.