ECG shows atrial fibrillation and ECHO shows Left atrial enlargement. Images FINDINGS: Acute and chronic rheumatic hea disease A-Aschoff body in a patient with acute rheumatic carditis. B- Acute rheumatic mitral valvulitis: Small vegetations (verrucae) are visible along the line of closure of the mitral valve leaflet C- Neovascularization of anterior mitral leaflet D- Myxomatous degeneration of the mitral valve. This 35-year-old woman most likely has atrial fibrillation with tachycardia that is irregularly irregular. One common cause of atrial fibrillation is left atrial enlargement. In this patient, the history of childhood fever and joint pain likely is the result of streptococcal caused rheumatic fever. If untreated, the microorganism can cause inflammation of the mitral valve, leading to mitral stenosis. After 3-5 years, the mitral stenosis is likely to worsen, leading to atrial enlargement, fibrillation, and pulmonary edema with intolerance to physical exeion.