Dallas ? New guidelines out today switch up the steps for CPR, telling rescuers to start with hard, fast chest presses before giving mouth-to-mouth.

The change puts “the simplest step first” for traditional CPR, said Dr. Michael Sayre, co-author of the guidelines issued by the American Heart Association.

In recent years, CPR guidance has been revised to put more emphasis on chest pushes for sudden cardiac arrest. In 2008, the heart group said untrained bystanders or those unwilling to do rescue breaths could do hands-only CPR until paramedics arrive or a defibrillator is used to restore a normal heart beat.

Now, the group says everyone from professionals to bystanders who use standard CPR should begin with chest compressions instead of opening the victim’s airway and breathing into their mouth first.

The change ditches the old ABC training — airway-breathing-compressions. That called for rescuers to give two breaths first, then alternate with 30 presses.

Sayre said that approach took time and delayed chest presses, which keep the blood circulating.

“When the rescuer pushes hard and fast on the victim’s chest, they’re really acting like an artificial heart. That blood carries oxygen that helps keep the organs alive till help arrives,” said Sayre, an emergency doctor at Ohio State University Medical Center.

“Put one hand on top of the other and push really hard,” he said.

Sudden cardiac arrest — when the heart suddenly stops beating — can occur after a heart attack or as a result of electrocution or near-drowning. The person collapses, stops breathing normally and is unresponsive.