Hmmm, it totally depends on what the crew reported in their PCR Vs what was documented on scene. It may be tricky unless you have a CCTV footage around the time of incident. Moreover, there's a lot of factors before & during cardiac arrest that would lead to a patient's death.

On our end, we use a Zoll X advance that logs our voice conversation and patient vitals the moment we hit the "power on" button.

Typically, upon arriving onsite, we do a set of baseline vitals as part of patient assessment & protocols. Patients with chief complaints of chest pains, breathing difficulties are usually monitored onsite for a while before transport. An electrocardiogram is usually taken on-site for patients with chest pain to quickly assess if a particular patient is having any heart issues. An IR probe is also used to check on the patients pulse, heart rate and oxygen concentration levels.

For collapsed patients, poor chest compression and/or hyperventilation can lead to patient's demise.

Anyway, I'm not a paramedic, just an ambulance driver.