A 74 year old lady called an ambulance for an acute chest pain. She has a history of diabetes died in the ambulance. What is the most likely cause of death?

A 74 year old lady called an ambulance for an acute chest pain. She has a history of diabetes mellitus and hypertension, and is a heavy smoker. Paramedics mentioned that she was overweight and recently immobile because of a hip pain. She collapsed and died in the ambulance. What is the most likely cause of death?