Buffalo Bills safety Damar Hamlin suffered a cardiac arrest on the field after making what appeared to be a routine tackle against the Bengals. This caused a frightening scene: Hamlin was administered CPR on the field as players from both teams watched in horror. Hamlin survived and is reportedly making "remarkable" progress in his recovery. We connected with interventional cardiologist, Daniel Kiss, M.D., to discuss his take on what happened and the importance of knowing CPR.