A committee has been appointed to investigate the deaths of four individuals at the Colombo National Hospital, the Ministry of Health said today.The four patients had died after undergoing heart surgery at the hospital this week. Health Minister Dr. Rajitha Senaratne has appointed a three member committee to investigate the deaths and submit a report today.According to the Health Ministry, the four patients were among six patients who underwent heart surgery at the hospital on Monday. (Colombo Gazette)