Carnitine: Its Crucial Role in Metabolic Health and Cardiovascular Function L carnitine Supplementation as Treatment for Cardiac Fibrosis and Heart Failure with Preserved Ejection Fraction The Effect of Carnitine Supplementation on Left Ventricular Function: Lessons from Current Evidence and Insights for Future Studies The Potential Connection Between Mechanical Stress and Heart Failure with Preserved Ejection Fraction: Mechanistic Insights and Therapeutic Potential