The CEOs for two Twin Cities major healthcare systems say their proposed merger will mean better quality healthcare for patients at a more affordable cost. Bloomington-based HealthPartners and St. Louis Park-based Park Nicollet will combine operations Jan. 1 if regulators approve. Merging the two non-profits would create a massive health organization with annual revenues of about $5 billion. The combined operations will include Park Nicollet Methodist Hospital in St. Louis Park, four HealthPartners hospitals: Regions Hospital in St. Paul, Lakeview Hospital in Stillwater, Hudson Hospital in Hudson, Wis., and Westfields Hospital in New Richmond, Wis. Officials say patients shouldn't notice any interruption and can expect to use their clinics and health plans as before.