The study team will examine effects of elevated plasma ketones caused by 12-week treatment with an SGLT2i (empagliflozin) treatment in participants with T2DM and HF. The study team will focus on three possible mechanisms of action for these effects and test the following:~(i) Skeletal muscle bioenergetics. Using 31P-MRS, the team will quantitate phosphocreatine [PCr], ATP, inorganic phosphate, phosphodiester, and intracellular pH. With 1H-MRS, and will measure intramyocellular lipid content at rest and ATPmax production after exercise. The team will examine the relationships between phosphorous metabolite concentrations, intramyocellular lipid content, and ATP generation before and after 12 weeks of SGLT2 inhibition.~(ii) Cardiopulmonary functional capacity.~(iii) Improvements in Patient-Reported Outcomes (PRO). The Patient-Reported Outcomes Measure Information System (PROMIS) Item Bank v2.0 - Physical Function - Short Form 20a will be used to evaluate self-reported physical function and well-being. This tool is a well-developed and validated method to obtain patient self-reported parameters of health in adults.
The study team will examine the effects of SGLT2i (and SGLT2i-induced increases in plasma ketone concentrations) on skeletal muscle and cardiac ketone uptake, skeletal muscle bioenergetics, cardiopulmonary exercise capacity, and patient-reported functional outcomes.