Letterman back in 'Late Show' business

He did let the shield down once, though, after introducing the six doctors and two nurses who formed his medical team.

"It was five weeks ago today that these men and women [including a heart surgeon from Lubbock] saved my life," Mr. Letterman said, his voice breaking slightly. "The reason you get through it is because these people get you through it."

He then dubbed them his "medical all-stars" after shaking their hands.

Basking in a one minute, 22 second ovation, including chants of "Dave! Dave!," Mr. Letterman opened the show by touching his toes and telling viewers, "Wait'll you hear what happened to me."

He dismissed lesser bypasses - "A double is like havin' your teeth cleaned!" - before getting down to medical terms.

"Bypass surgery is when doctors surgically create new blood flow to your heart," he explained. "A bypass is what happened to me when I didn't get The Tonight Show."

Across the dial, Tonight host Jay Leno tried to blunt Mr. Letterman's triumphant return by booking Howard Stern as his principal guest.

Mr. Stern, an employee of CBS, said he had "picked the right night to be on. Everybody's tuning over to see if there's a corpse on another network."

Unbilled walk-on guest Jerry Seinfeld covered that particular base by telling Mr. Letterman, "I thought you were dead."

"I'm on CBS. I ain't dead," Mr. Letterman retorted before adding, "Why don't you go on home to your wife?"

Mr. Letterman later promised to give everyone in the studio audience a commemorative heart bypass T-shirt. It's white with six big stitches and a surgical scar on the front.

Principal guest Regis Philbin - yes, him again - repeatedly referred to Mr. Letterman as "the Big Man." As in: "It's good to have the Big Man back, isn't it?!"

But Mr. Big initially was more interested in quizzing Mr. Philbin about his salary as host of ABC's Who Wants to Be a Millionaire.

When the host asked, "Are you makin' a lot of dough, Regis?" he replied: "No, I'm not, as a matter of fact. They're still talking about it."

"Those pantywaists at ABC are not paying you what you're worth?" Mr. Letterman persisted.

"I don't think so," he said, prompting Mr. Letterman to tell him: "That stinks. That really stinks." And later, "I can't believe those bastards at ABC are screwing you."

The exchanges provided some extra news on a night that otherwise belonged to America's most famous recovering heart patient. Mr. Letterman's other guest, Robin Williams, came out in doctor's scrubs and mugged until his time was up.

Time did not allow for Late Show's signature Top 10 list, but there was more than enough bypass humor to compensate. Here's one for the road:

"Thank god I lived long enough to see the Super Bowl halftime show. What the hell was that?"