The patient is an 81-year-old woman diagnosed with a metastatic cardiac tumor and left ventricular outflow tract stenosis. Due to the high risk of sudden death associated with tumor ablation, an emergency tumor resection was performed. The patient exhibited cancer cachexia and was in a highly frail state. There were concerns about delays in postoperative recovery and chemotherapy; hence, minimally invasive cardiac surgery was performed via a transmitral approach. To secure the visual field, a longitudinal incision was made at the anterior apex of the mitral valve. The visualization was excellent; thus, the tumor could be easily resected. This report highlights the effectiveness of the transmitral approach for accessing a cardiac tumor located in the middle of the left ventricular septum and reviews relevant literature.