NEW ORLEANS — A federal jury handed Merck & Co. a major victory yesterday, clearing the drugmaker of any responsibility in the death of a 53-year-old Florida man who had a heart attack after taking its once-popular painkiller Vioxx for less than a month.

This was the second court victory for Merck, and the first in a federal court. The company had argued in this case that plaintiff lawyers never proved any link between Vioxx and the heart attack that Richard "Dickey" Irvin suffered in 2001. Merck's lawyers contended that Irvin's age, gender and diet all put him at risk for heart attacks.

It was also the second time jurors heard the case brought by Irvin's family. In Houston, where the case was heard in November and December because of disruptions from Hurricane Katrina here, jurors were unable to reach a verdict.

Merck won a state case in New Jersey last year, while it lost one in Texas.

Irvin's widow, Evelyn Irvin Plunkett, along with the youngest of their three daughters and their only son, testified that Irvin's health had been excellent up to his heart attack.

Plunkett left the courtroom in tears without talking to reporters.

"Obviously the family is very upset," said her attorney, Andy Birchfield.

He said the biggest problem was Judge Eldon Fallon's ruling, shortly before the trial, that two of their experts — a cardiologist and a pathologist — could not testify that Vioxx was to blame for Irvin's heart attack. They were experts in their fields, but not about Vioxx, the judge ruled.

"With all due respect, we think that (ruling) was error," said Birchfield. He said he would be talking with Plunkett about whether to appeal.

A lawyer for Merck, Phil Beck, said he believes that the verdict indicates the jury decided "the Merck scientists lived up to their legal and ethical responsibilities when manufacturing and marketing Vioxx and making the decision to take Vioxx off the market."

Shares of Merck & Co. gained 90 cents, or 2.5 percent, in after-hours trading. The shares closed 7 cents higher, at $36.05, in regular trading yesterday on the New York Stock Exchange.

The jury deliberated for three hours and 40 minutes, the shortest period of any of the four juries yet in Vioxx-related cases.

Observers said the verdict was a clear victory for Merck, but the company will face more formidable cases later this year with plaintiffs who took Vioxx for 18 months or longer.

Merck removed the drug from the market after a study showed it doubled patients' risk of heart attacks and strokes after 18 months.

Still, Howard Erichson, a professor at Seton Hall Law School, said this verdict may keep plaintiff lawyers from filing short-term use cases. It may also help Merck because the judge overseeing all the federal cases has said he wants to discuss a settlement after trying the first four.

"To the extent that ultimately there is a wide settlement, this win plays in Merck's favor," said Erichson.

So far, about 9,600 cases related to Vioxx have been filed.

Analysts have estimated that Merck's liability could reach $50 billion. So far the company has set aside almost $1 billion for legal fees.

Another case is going on in state court in Texas.