Dwayne, I wouldn't say as much out loud, but I would follow with implied consent. My feeling is that although the patient previously declined care, he may not have completely understood the ramifications of his choice, or didn't believe it when the paramedic told the patient in clear and concise terms what would happen without medical attention.
Remember, one of the significant signs of a heart attack is denial, but there eventually comes a time when the patients have had the sudden "Oh shit" moment and realise that they're going to die for a stupid reason. I'll always follow up treatment with an implied consent, even after being told "Don't touch me if I pass out." because that is not a valid or legal advanced care directive and I feel I am doing the best for my patient. Having family there makes it easier too.