Metabolic Cardiomyopathy

Abstract

Metabolic cardiomyopathies represent a large heterogeneous group of diseases caused by inborn errors of metabolism (IEM). So far, more than 1000 distinct disorders of metabolism have been described. Cardiac involvement is present in about 5% of these metabolic defects. While in some diseases, the cardiac involvement is representing the dominant and potentially fatal condition, in the others it may be only part of a complex multisystemic disease manifestation. Cardiac involvement has been described in various types of metabolic defects including lysosomal storage diseases, different types of glycogenoses and other inborn errors of metabolism such as disorders of amino acid metabolism, organic acid metabolism, and fatty acid metabolism. In broader term of the definition, metabolic cardiomyopathies include also oxidative phosphorylation defects (OXPHOS) usually listed among mitochondrial diseases. Most IEM are inherited as autosomal recessive traits, however, some highly prevalent diseases with cardiac involvement are X-linked (Anderson Fabry disease, Hunter syndrome-type II mucopolysaccharidosis, Danon disease). Cardiomyopathies caused by IEM are phenotypically heterogeneous, most of them characterized by cardiac hypertrophy and/or by different degrees of progressive dilatation and systolic dysfunction resulting in dilated cardiomyopathy phenotype. However, several diseases may appear as restrictive cardiomyopathy phenotype. The tableau of the disease may include different electrophysiological changes (short PR, preexcitation pattern, AV conduction abnormalities) and/or valvular involvement.