There have been no recent descriptions of the spontaneous conversion of long-standing atrial fibrillation (AF) or flutter (AFl) to sinus rhythm which, in the past, has been associated with rheumatic mitral valve disease and treatment with digoxin. We present 3 contemporary cases, all of whom progressed from AF to slow AFl and then spontaneously converted to slow sinus or junctional rhythm. None of these patients had rheumatic heart disease or were treated with digoxin. In conclusion, we believe that they provide support for the broader view that this uncommon phenomenon is associated with a severe atrial myopathy due to scar and inflammation.