The Carnitine/Acylcarnitine Axis in Cardiomyopathy: From Metabolic Reprogramming to Biomarker Potential

This narrative review summarizes current evidence on the carnitine/acylcarnitine axis in cardiomyopathy, with emphasis on metabolic remodeling, biomarker potential, and translational relevance. Cardiomyopathy is increasingly recognized as a metabolically heterogeneous disorder characterized by impaired myocardial energy homeostasis, mitochondrial dysfunction, and altered substrate utilization. Among the metabolic pathways involved, the carnitine/acylcarnitine axis has emerged as a key system because of its role in fatty acid transport, β-oxidation, and mitochondrial metabolic flexibility. Alterations in circulating and tissue acylcarnitine profiles may reflect incomplete fatty acid oxidation, mitochondrial dysfunction, and phenotype-specific metabolic remodeling. This review discusses the biological and clinical significance of the carnitine/acylcarnitine axis in cardiomyopathy. The physiological role of carnitine in myocardial energy metabolism, the mechanisms leading to acylcarnitine accumulation, and the relationship of these alterations with myocardial dysfunction, oxidative stress, and cardiac remodeling are examined. Available evidence on circulating acylcarnitine signatures in ischemic, non-ischemic, hypertrophic, and dilated cardiomyopathies is also evaluated, particularly regarding their diagnostic and prognostic biomarker potential. In addition, the translational implications of carnitine-centered metabolic profiling are discussed, including its relevance for patient stratification, phenotype differentiation, and targeted therapeutic approaches. Although growing evidence supports the value of acylcarnitine profiling in cardiometabolic disease, heterogeneity in study design, analytical platforms, and patient populations remains a major barrier to clinical implementation. Overall, the carnitine/acylcarnitine axis represents a promising bridge between mechanistic understanding and biomarker development in cardiomyopathy. Future standardized and phenotype-specific studies may clarify its role in precision diagnosis and metabolically guided therapeutic strategies.