A 29-year-old female patient in the 28th week of pregnancy was diagnosed with a cardiac tumor. We performed tumor excision and mitral valve replacement, and her baby was born successfully with cesarean section on the 9th day after cardiac surgery. After this event, 8 cycles of chemotherapy were administered. After 10 months, metastatic intimal sarcoma of the right ovary developed, and a right salpingo-oophorectomy and omentectomy was performed. However, the patient died of sudden onset of intractable ventricular fibrillation.