If big pharma's not interested, would the costs of getting this kind of therapy into paramedics' hands be within the reach of private philanthropy (e.g. Gates foundation or YC's recent non-profit efforts)?
Glucose, insulin and potassium are already readily available on every ambulance, so all you'd need is a clinical trial proving that the mixture is effective and safe to use for heart attack patients. The costs of a clinical trial seem well within the reach of private philanthropy, especially since this isn't an experimental drug where you'd have to start from scratch--all three of those meds have been extensively studied both separately and in combination. (Glucose and insulin is a combination commonly used to treat high potassium levels, for example.)