Myocardial pathology is rarely associated with myasthenia gravis (MG). We describe a case of newly diagnosed MG with decompensated heart failure [stress-induced cardiomyopathy (SICM)] that occurred during the crisis phase. Case report and review of literature. A 42-year-old woman underwent chemotherapy followed by a transsternal resection of a malignant epithelioid thymoma invading the pericardium. A month after surgical resection, she developed progressive oropharyngeal symptoms with respiratory distress requiring tracheal intubation. Cardiac evaluation on the day of admission showed a normal ejection fraction, which rapidly decreased to 15% on the second hospital day and recovered to 45% after 1 week. Review of the literature revealed 4 myasthenic patients who developed SICM in the crisis phase; all improved with treatment. SICM may occur in MG crisis, especially in the presence of malignant thymoma. All previous cases including our patient had improved myocardial function and clinical outcomes.