Spontaneous reversion of long-lasting chronic atrial fibrillation to sinus rhythm.

We report a case of a 72-year-old lady with rheumatic heart disease and chronic, long-lasting atrial fibrillation, who reverted spontaneously to sinus rhythm. Doppler study showed evidence of mechanical contraction of the right but not of the left atrium. This may be a sign of marked histologic changes in the atria and may require the insertion of a permanent pacemaker, because of subsequent development of sinus bradycardia.