I Came Home To Find My Husband Lying On Our

I came home to find my husband lying on our bed.across it as if he had st on the edge to get up from bed or get into bed. , but instead fell backwards onto the bed. His mouth was partially open and his eyes partially..mostly open. It only to less than 5 seconds to realize he wasn't playing a trick on me.....cause he never moved. His face was pale and lips tinged blue around the outside. I stated CPR and after removing my mouth each time there was a gurgling sound. Why was there a gurgling sound...had he died instataneous ly when the heart attack occurred?. How long before I found hm had he been dead?