Simplify the following text for a Grade 14 native English-speaking person.
Original: First aid treatment for cardiac arrest usually begins with cardiopulmonary resuscitation ( CPR ) to keep oxygenated blood flowing until medical treatment is available .
Simplified: The treatment for cardiac arrest is cardiopulmonary resuscitation ( CPR ) to provide circulatory support , followed by defibrillation if a shockable rhythm is present .