If you haven't heard of GoodSAM, you soon will. GoodSAM notifies off-duty first responders when someone nearby has called Triple Zero for a cardiac arrest. They're able to respond within minutes – sometimes seconds – while the ambulance is on its way. In an emergency, it can mean the difference between life and death. Twenty Victorians have already been revived because of this app – and now, we're expanding it to include all accredited and trained first aid responders. | Dan Andrews