Cardiac arrest is the number one cause of death in Canada. It is often the first symptom of cardiac disease for the victims. Eighty-five percent of victims collapse in their own home. Fifty percent collapse in the presence of a family member. Bystander cardiopulmonary resuscitation (CPR) can improve the chance to survive a cardiac arrest by three to four times, but needs to be started quickly. In most communities, less than 30% of victims receive CPR before the ambulance arrives. Currently, only 8% of cardiac arrest victims can leave the hospital alive.

Many things have been tried to improve the number of times people do CPR. So far, the only thing that really increased the number of times that someone did CPR is when 9-1-1 attendants started to give CPR instructions to callers over the phone. The only problem is that about 25% of cardiac arrest victims gasp for air in the first few minutes. This can fool the 9-1-1 callers and attendants into thinking that the victim is still alive.

The investigators have looked at all the studies on how to help 9-1-1 attendants to recognize abnormal breathing over the phone. The investigators have also learned what should be taught after finishing a large survey with 9-1-1 attendants from across Canada. This survey was done with the help of psychologists and other education experts. It measured the impact of attitudes, social pressures, and 9-1-1 attendants' perceived control over their ability to recognize abnormal breathing and cardiac arrest. Then the investigators developed a teaching tool which helped Ottawa 9-1-1 attendants recognize abnormal breathing. When they could do that, they could also recognize more cardiac arrest.

The main goal of this project is to use the tool developed in Ottawa in more centres to help 9-1-1 attendants save the lives of even more cardiac arrest victims across Canada.

Inclusion Criteria:

We will enroll ALL patients with prehospital cardiac arrest (absence of a detectable pulse, unresponsiveness, and apnea):

• That are of presumed cardiac origin;
• That occur in the catchment area of our participating sites; and
• For which resuscitation is attempted by a bystander and/or the emergency responders.

Exclusion Criteria:

• Cardiac arrest witnessed by paramedics after their arrival (no opportunity for bystander intervention);
• Patients younger than 16 years of age (cardiac arrest usually respiratory and rare in this population);
• Patients who are "obviously dead";
• Trauma victims, including hanging and burns; or
• Patients with cardiac arrest clearly of other non-cardiac origin including drug overdose, carbon monoxide poisoning, drowning, exsanguination, electrocution, asphyxia, hypoxia related to respiratory disease, cerebrovascular accident and documented terminal illness.

All patients with prehospital cardiac arrest (absence of a detectable pulse, unresponsiveness, and apnea) occurring in the catchment area of any participating site during the active study period.