Perhaps my understanding here is lacking, but that doesn't sound good at all. Feels like if someone has some sort of cardiac event, or, worse, isn't breathing, by the time the ambulance gets there, they'll be dead, with too much brain death for any resuscitation effort to be worth it.

How exactly do you expect an ambulance to be able to reach any part of a county in under 12 minutes??

Yes, I believe your understanding is lacking. Ambulances are dispatched for other medical emergencies as well. Compared to many other parts of Australia and even the world, the response time statistics claimed are very good.

Sadly, A heart attack can be fatal even with immediate medical intervention at a hospital. A defibrillator can only correct certain kinds of abnormal heart electrical activity.

In my experience as soon as the dispatcher understands it's a medical problem, has confirmed the address and that the patient is not breathing, they will begin talking the caller through performing CPR.

I suppose if I was concerned about it, the burden would be on me to move somewhere closer to the hospital or wherever the ambulance stages between calls. Unfortunqtely, there's always a chance no ambulance is available or that an accident has blocked the road.

How soon do you believe assistance should arrive?

Cardiac events don’t usually work like that. You could, for example, get permanent damage if your heart attack isn’t treated within 30 minutes (as a guideline, the circumstances vary heavily). Even an aneurism doesn’t often act quicker than 20 minutes. But ya, sub 10 minute response times only happen in a hospital, sub 1 minute response times in intensive care, etc…

Still, you feel like you are having a heart attack, call 911 (in the US) right away. The main time killer is probably just you recognizing that you need help (vs the time it takes to get help once called).