(CNN) -- It was 5:16 a.m. when the call came in to a 911 dispatcher in Madison, Wisconsin. The story, from Cathy Silver, came out staccato: Cathy's husband, Jim, was gagging, gasping for air. A nurse at the University of Wisconsin Hospital, Cathy could see that her husband, the father of four grown children, was in cardiac arrest.

Though trained in CPR, Cathy was flustered. "I can't do the breaths!" she shouted. Nevermind, said the dispatcher. Get over him, press on his the chest, circulate the blood. Help would be there soon.

Four minutes later, a Madison police officer arrived and took over. More chest compressions, still no breaths. By the time paramedics arrived, it was nearly 10 minutes since Jim had stopped breathing.

Fifty frantic minutes later, after more than a dozen electric shocks to the heart, seven injections of epinephrine, and one wild ambulance ride, Jim's heart regained a stable beat. A week later, he was up and talking in his hospital bed.

For years, anyone learning CPR -- emergency resuscitation -- was taught the "ABC": Check the airway for blockages, give breaths, then circulate the blood. New guidelines issued Monday by the American Heart Association turn that alphabet on its head, punctuating a shift that has led emergency responders to emphasize compression of the chest over all else when treating victims of cardiac arrest.

The new catch-phrase is "C-A-B" -- as in start pushing on the chest before doing anything else. The AHA guidelines also uphold a 2008 recommendation that untrained responders call 911 but then forget rescue breathing completely, and simply press on the victim's chest until help arrives.

Going a step beyond that, the 2010 guidelines "strongly recommend" that 911 dispatchers guide callers in "compression-only" CPR, sometimes known as CCR. However, medical professionals and trained lay people are still urged to give the victim two "rescue breaths" in between each series of 30 chest compressions.

All the changes apply only to adult victims who collapse of cardiac arrest; artificial respiration is still recommended for children and for adults in a few cases, including near-drowning and drug overdose.

The science behind the changes is simple. In an adult who has been breathing normally, for several minutes even after cardiac arrest there is enough oxygen in the bloodstream to maintain the heart and brain, as long as compressions circulate that oxygen.

In this scenario, pausing to provide oxygen through rescue breaths is not only unnecessary, but harmful because it requires the rescuer to stop pressing on the chest for at least several seconds.

Dr. Gordon Ewy of the Sarver Heart Center at the University of Arizona, who led some of the first animal studies on CCR, says rescue breaths can also be harmful because they cause lower air pressure in the chest cavity, which slows down circulation -- the most important element in the whole process.

The new guidelines also call for faster and more forceful compressions than in the past. The new standard is to compress the chest at least two inches on each push, at a rate of 100 compressions per minute. The AHA says the perfect pace is that of the Bee Gees' "Staying Alive."

In recent months, after the guidelines were written but before their release Monday, additional research has added to the evidence that chest compressions are the key to effective resuscitation. But Dr. Peter Nagele, whose paper in the Lancet recommended compression-only for bystanders, says the guidelines are not likely to go further. "This [the AHA guidelines] is a consensus document, and there are a lot of opinionated researchers in this field."

One of those opinionated researchers is Ewy. A fierce advocate for "compression-only CPR" and a sometime-thorn in the side of the AHA, Ewy issued a statement sharply criticizing the new guidelines, saying they don't go far enough.

"Why do the Guidelines state that, 'Rescuers should avoid stopping chest compressions and avoid excess ventilations' and yet not advocate chest-compression-only CPR?" His statement said. "The 'Guidelines' have lost or are in danger of losing their credibility."

In an interview, he said the evidence shows CCR is superior to CPR, even when done by medical professionals.

Ewy does agree that some patients -- including young children, and victims of drug overdoses and near-drownings -- should receive rescue breaths.

Dr. Ben Bobrow, who also helped write the new AHA guidelines, says the controversy should not be overblown.



"The difference between the specific types of CPR isn't nearly as large as the difference between not doing CPR, and getting people to do any kind of CPR at all," says Bobrow.

One clear benefit of eliminating mouth-to-mouth is that by eliminating fear of infections, you get more people to jump in. As director of emergency services for the state of Arizona, Bobrow has made public education a major focus, with billboards, radio spots and other messages, driving people to a teaching website. Since 2004, the number of bystanders who attempt CPR has gone from 28 percent to 40 percent.

"But that needs to be 70 percent," Bobrow said. "The major hurdle is getting people to act, and not just do nothing. What we need to do is change the culture, so it's unacceptable to do nothing."

Dr. Michael Sayre, an emergency physician at the Ohio State University and a spokesman for the AHA, says the odds of survival roughly double if a bystander steps in to provide CPR. According to Sayre, if the national rate of bystander assistance could be raised to 70 percent -- the same rate as the city of Seattle, where a public education campaign has run for decades -- a minimum of 20,000 lives would be saved every year.

Two and a half years later, Jim Silver recalls his brush with death in a soft voice, with an occasional chuckle. The former superintendent of Madison's Catholic school system bears no measurable injury from that frightful morning. His cardiac arrest was caused by a coronary blockage and he underwent a quadruple bypass operation after his resuscitation, but he's physically active as ever, logging 3,000 miles this year on Madison's omnipresent bike paths.

He has no memory of the incident, but reads aloud from an e-mail his wife recently received from the police officer who helped to save him. "I've thought a lot about that morning... I'm really glad I was able to help Jim."

"Me too, me too," he laughs quietly. Silver is writing his own e-mail now, in reply. He narrates over the phone. "Thanks for saving my life. It seems like a considerable understatement, but I'm thankful for your efforts on my behalf. I'm glad I'm alive to enjoy the fall weather." A pause, then more. "Without those constant compressions by you and others, a lapse of a minute or so, all this would have been for naught."

No longer writing, just talking now, Silver finishes his thought. "It's kind of a mind-blower. I was really shaken. But I feel great."