Guoguo, a 3-month-and-18-day-old infant, was admitted to the Tongzhou branch of Beijing Anzhen Hospital on October 12 for a congenital ventricular septal defect. The surgery was originally expected to take 4 hours but lasted about 18 hours. The next morning, the family received a notice of death without having received a critical condition notice. The cause of death remains unexplained, and an autopsy is currently underway.