NEW YORK--(BUSINESS WIRE)--Fitch Ratings has affirmed the 'F1+' rating on Adventist Health System Sunbelt (Adventist) approximately $335.5 million of outstanding variable rate debt issued by Highlands County Health Facilities Authority supported by self-liquidity. Adventist's Long-term rating is 'AA'. Key Rating Drivers SUFFICIENT INTERNAL LIQUIDITY: The 'F1+' rating reflects the strength of Adventist's cash and investment position to pay the cost of a mandatory tender on its self-liquidity deb