A 56-year-old man who had twice previously undergone orthotopic heart transplantation was admitted with dyspnea and heart failure symptoms. A biopsy excluded rejection. Left heart catheterization revealed a coronary cameral fistula. After the patient was given mild diuretics, his condition improved. No significant fistula flow was detected, and he was discharged. Several months later, the patient was readmitted with worsening chest pain and dyspnea. Left ventricular end-diastolic pressure and flow through the fistula were increased. To correct the coronary cameral fistula, we performed a coil embolization without complications. Several months later at follow-up, the patient's symptoms had resolved, and his left ventricular end-diastolic pressure had normalized. We conclude that coronary fistulas may be caused by trauma to the heart during the de-airing process, which may be prevented in the future with the development of safer and more effective de-airing techniques.