Commotio cordis during prolonged cardiac ventricular repolarization due to exercise-induced hypokalemia: A case report

Commotio cordis is ventricular fibrillation after a direct precordial blow without mechanical damage to organs. Early recognition and prompt cardiopulmonary resuscitation with defibrillation save lives. According to previous reports, the major determinants of commotio cordis include location and timing of the blow. Other risk factors are young age, a thin and undeveloped chest cage, and a small hard spherical projectile. The pathophysiology of commotion cordis remains uncertain, such as individual susceptibility to prolonged repolarization and long QT. A 32-year-old man suddenly collapsed after a direct blow to the anterior chest from an elbow during a basketball game. A bystander called an ambulance and activated the emergency medical service immediately. Dispatch assisted the bystander with cardiopulmonary resuscitation via telephone. An automated external defibrillator was applied when emergency medical technicians arrived, which showed ventricular fibrillation. The patient regained a pulse after the first electrical shock and five-cycle-chest compression. Further examinations revealed a long QT on electrocardiogram and hypokalemia. The QT interval was within normal limits without any ventricular arrhythmia after the potassium level had been normalized. This case reminds physicians of the risk of commotio cordis associated with exercise-induced hypokalemia. An electrocardiogram should be checked for QT prolongation immediately after return of spontaneous circulation in patients of sudden cardiac arrest. Supplying adequate potassium for hypokalemia related QT prolongation should be considered as treatment and primary prevention in such case.