To Mend a Heart — Elizabeth Harrison

The cardio-thoracic unit at the Central was world famous, thanks to Marcus Northiam, the brilliant but difficult heart-surgeon who dominated it, and his able first assistant, James Leyburn. But James's private life was not as successful as his career. It was years since he'd been jilted by Melissa, yet somehow he'd never been able to disentangle himself, until her adorable younger sister Emily joined the unit . . . Suddenly life looked marvelous to James, and then Northiam dropped his bombshell.