Dr. Selvyn Bleifer, a cardiologist and associate clinical professor at UCLA, says most people are "fully recovered" from a surgery like Letterman's by the end of six weeks, and that some of his patients have been back to work in two weeks.
"It's important to remember that once he has the operation and the arteries are bypassed, the circulation to the heart is now virtually normal. So his heart is better than it was before, and the recovery period is necessary because they had to open the chest and close the chest. . . . This is a wake-up call that he has a problem. He wants to do everything he can to prevent a recurrence of the problem."
Does that include hosting a late-night talk show? Though Letterman is notoriously self-critical when it comes to himself and his work, some doubt he'll want to stay away from work any longer than he has to.
"His whole day was about work and keeping himself healthy," said Jeff Altman, among Letterman's circle of comedian friends from the Los Angeles comedy scene of the 1970s and early '80s, when Letterman was a regular at the Comedy Store and Improv.
More often than not, Altman said, Letterman's day would go as follows: Wake up at 4 a.m., run seven miles. Get to work at 9, then spend the next 12 hours at "The Late Show."
"I think that Dave will be looking forward to getting back to work, if for no other reason than he'll be bored senseless," Altman said.