a, Timeline for β-hydroxybutyrate (βHB) injection experiment in which CS-MPC2−/− mice were injected i.p. with saline vehicle or 10 mmol/kg βHB daily from 12 to 14 weeks of age. b-h, Echocardiography measurements before and after 2 weeks of daily i.p. injection of saline vehicle (Veh) or 10mmol/kg β-hydroxybutyrate. Left ventricular (LV) mass index, end-diastolic volume (EDV), end-systolic volume (ESV), heart rate (HR), relative wall thickness (RWT), ejection fraction (EF), and cardiac output (CO) (n=4 Veh, 5 βHB). i, Plasma total ketone body concentrations (n= 4 Veh, 5 βHB). j, Heart weight normalized to tibia length (n= 4 Veh, 5 βHB). k, Gene expression markers of hypertrophy, heart failure, and fibrosis from hearts after 2 weeks of daily vehicle or βHB treatment (n= 4 Veh, 5 βHB). Data presented either as PRE-POST, or mean ± s.e.m. shown within dot plot. Each symbol represents an individual sample. Two-tailed unpaired Student’s t test.