The NY Times has a nice first person story from a cardiologist who examined an intern for chest pain and made the wrong call. Nobody died; the man was correctly diagnosed the next morning and treated for a blockage.
What's interesting is that the cardiologist struggled with the morality of what to say to the patient. Years of experience caution doctors against admitting anything, or even sincerely apologizing for an incorrect diagnosis.
Anyway, the story tugged at me a little bit, so here it is: