This event – a heart attack – is the leading cause of in-flight death, and the leading medical cause of diversions. Medical kits include aspirin and a vasodilator spray to keep blood flowing when there is chest pain. In case of cardiac arrest, cabin crew are trained to give CPR, while many airlines now also carry defibrillators to restart the heart. Cardiac monitors are use increasingly, so that data can be transmitted to medical advisors on the ground.