At Clydebank's Golden Jubilee University National Hospital, Chuck Maclean and his team carry out a complex five-hour operation on 60-year-old Margo, who is in urgent need of life-saving surgery to fix a faulty heart valve. Donald, 78, needs an operation to implant a defibrillator to control a dangerous heart rhythm, but the procedure may have to be put on hold as he collapsed overnight, causing a head injury, and he needs a CT scan to find out if there's been any bleeding within his brain