The man in the white baseball cap had just finished playing poker when he cashed in his chips in a very big way.

The grainy videotape, taken from a surveillance camera at the Boulder Station Casino, shows him lying on the floor next to a roulette table. He's in full cardiac arrest. A security officer, by chance walking by, calls for help on a radio and then starts working on him. A woman shoots a look over her right shoulder, but keeps playing.

Two minutes and 32 seconds after the man's collapse, two other guards arrive, one carrying a box about the size of a briefcase. From it they take two large plastic patches attached to wires, which they paste to his chest. The man's left hand, all of him that's now visible, jumps off the floor, the effect of 200 joules of electricity delivered in less than a tenth of a second.

By the time the county emergency medical technicians arrive nine minutes and 35 seconds into the drama, the man is sitting up and protesting. Within two hours, in fact, he's checked himself out of the hospital against medical advice. Since that day 20 months ago, he's been seen more than once back at the tables, trying his luck again.

Scenes like this have occurred dozens of times in the last two years, since casinos here began training security guards in the use of portable heart-shocking devices, known as "automated external defibrillators."

Today, Las Vegas's gambling halls are about the safest public places in the world, at least in terms of their preparation for cardiac disaster. They're leading a movement in the United States to make automated defibrillators what life jackets and seat belts once were -- pieces of technology that our risk-averse society can't imagine ever having lived without.

"Someday, these things may be as common as fire extinguishers," said Richard Hardman, training coordinator for the Clark County Fire Department, and the person largely responsible for bringing defibrillators to Las Vegas's entertainment industry.

A bill before Congress, the Cardiac Arrest Survival Act, would direct the secretary of health and human services to promote the outfitting of all federal buildings with the devices, and the training of people to use them.

The American Heart Association and the American Red Cross are the driving forces behind the bill, which has been offered twice before. This bill's sponsors are Sen. Slade Gorton (R-Wash.), whose state is home to two of the three makers of the devices, Medtronic Physio-Control and Heartstream, and Rep. Cliff Stearns (R-Fla.).

Even without the bill, the devices are proliferating in federal offices. Congress and the Supreme Court have them, and the Washington headquarters of HHS, Labor, EPA and several other agencies are getting them. The Internal Revenue Service and the Federal Deposit Insurance Corp. are putting them in "selected buildings" nationwide.

About 40,000 of the devices will be sold this year, with the market doubling about every 18 months. More than a dozen airlines carry them on all planes. American Airlines, the first domestic carrier to acquire them, reports eight "saves" out of 17 uses in two years.

USX Corp. recently got automated defibrillators for two steel mills near Pittsburgh, and over the next year will outfit four more plants, as well as four oil refineries run by its subsidiary, Marathon Oil. John Hancock Mutual Life Insurance Co. has them in five office buildings at its Boston headquarters. R&B Falcon Corp., an oil drilling contractor in Houston, bought 88 for its rigs and offices.

"We want to make certain that we give our employees the best possible care. The defibrillator is as important to us on a rig as any other safety equipment," said Robert B. Carvell, the company's director of risk management.

Nationwide, about 250,000 people die each year of sudden cardiac arrest, which is sometimes also called "sudden death." Although regional variations in medical care have been widely documented in recent years, few are as dramatic as those seen in the treatment of this condition.

Seattle and its suburbs in King County, Wash., have among the highest save rates, 14 percent and 18 percent, respectively, with a save defined as a resuscitated person leaving the hospital alive. New York's, however, is only 1.4 percent, and Chicago's is 2 percent.

By some estimates, one-quarter to one-third of people in sudden cardiac arrest might be saved with optimal emergency care, including faster defibrillation. To achieve that, however, lots of ordinary people will have to be willing to do something they've only seen on "ER."

Contrary to popular impression, electricity isn't a general tonic capable of jolting errant hearts back to work. There are rhythms that don't benefit from shocking, and ones made worse by it. A heart in electrical standstill, for example, can't be restarted with a defibrillator.

However, shock is the treatment of choice for ventricular fibrillation, the heart rhythm found in about 80 percent of cardiac arrest victims in the first minutes after collapse.

Of 127 people who have collapsed, pulseless and not breathing, in a casino equipped with a defibrillator, 51 have been revived and have gone home alive. This "save rate" of 40 percent is roughly five times that of the rest of the country.

Automated defibrillators cost about $3,000 apiece. Although it is possible to operate one without training, most places give security guards or other employees three to five hours of instruction.

Current models require only that a person place two electrode patches as instructed on the victim's chest and press a start button. The machine takes an EKG and analyzes it, and a voice prompts if the rhythm is one that can be shocked. (If it isn't, the device doesn't charge up, so ill-advised shocks are impossible.) The machine even shouts "Stand clear!" although the operator has to deliver the shock with a button.

Public access to automated defibrillators is getting its biggest test in Chicago's airports, where 33 were installed at O'Hare and seven at Midway in June. They are in plain view, rigged to dial 911 when removed from the wall.

"The wider use of defibrillation is not a new wish," said Peter Safar, a longtime resuscitation researcher. "The technology has now caught up with the wish."

Their notable success in reviving Las Vegas's downed gamblers is attributable to two things -- access and speed.

Although not every person in cardiac arrest can be saved by electricity, those who can need to be shocked within five minutes of collapse to have a reasonable chance of survival. There are now about 350 automated defibrillators in 59 Las Vegas casinos. As a rule, security guards can get one to any place on a property in less than three minutes.

On a recent morning, Paul Ready, medical training officer for Sam's Town, dropped a mannequin on the floor of the sprawling casino's sports bar, which was closed for cleaning. It was time for the monthly defibrillator drill. An assistant called the casino operator to say that a member of the janitorial crew was down.

First officer on the scene: 1:05 minutes. Equipment arrival: 1:35. Rhythm analysis: 2:38. First Shock: 2:52.

"I'm glad to have these. I might need one one day," said Henry McCallum, 56, red-faced and sweating, when the drill was over. He once was a police officer in Manchester, N.H., where, he says, "we ran the city ambulance with absolutely no training." He doesn't mind being better prepared now.

Some companies fear that training employees to operate an automated defibrillator may expose them to lawsuits if victims die. The Nevada legislature addressed this problem when it was raised by casino owners. It extended the state's Good Samaritan law to cover nonmedical workers, such as security guards, who defibrillate people on the job.

In recent years, 43 states have enacted laws protecting rescuers using defibrillators (and in some cases, the companies who own the devices) from liability suits. The bill before Congress would extend protection to the rest. Maryland and Virginia each have such laws, but the District doesn't.

There have been no lawsuits over deaths following the use of a defibrillator by "lay" rescuers. Most experts, in fact, think risk to employers lies elsewhere.

"If there's any threat of litigation, it is more for not providing the device," said Richard Hamburg, director of government relations for the American Heart Association.