Myasthenia gravis--an unexpected cause of respiratory failure and reversible left ventricular dysfunction after cardiac surgery.

We report a case of postpericardiotomy myasthenia gravis. A 68-year-old male patient without prior history of neuromuscular or autoimmune disorders presented with respiratory failure and severe left ventricular dysfunction four weeks after mitral valve replacement. Markedly elevated acetylcholine receptor antibodies were noted, and the patient responded promptly to immunologic therapy. Awareness of this rare but potentially fatal consequence of cardiac surgery may allow the early institution of specific treatment.