Even a cursory exploration into the physiology of atp would demonstrate the ineffectiveness of this method - the heart consumes around 6kg of ATP daily, or 250g an hour, which means you’d need to provide it with more than 4g a minute just to stay pumping in isolation. Which then leads to the issue of actually delivering the ATP to the correct part of the heart (god forbid you have a posterior infarct), and ensuring enough of a quantity to keep pumping after that first bolus dose of ATP, which isn’t going to spread far given the lack of a distribution system since there’s some blockage upstream