Heritable arrhythmias, cardiomyopathies, and valvulopathies.

Arrhythmias, cardiomyopathies, and valvulopathies are the most frequent forms of heart disease that occur during the years of peak productivity. They have interrelated pathogenetic bases and may occur in combinations. Cases in which there is involvement of other body systems are so frequent as to suggest a need for careful cardiological evaluation of any patient with dysmorphic features or an inborn error of metabolism. Recent advances in embryology and molecular genetics have increased our understanding of the heritable arrhythmias, cardiomyopathies, and valvulopathies but clinical delineation of all of them predated those developments. Symptomatology may be confusing or absent, so electrocardiogram and echocardiogram are required for diagnosis. Holter monitoring is productive if echocardiogram and electrocardiogram are not diagnostic. For some varieties of heritable arrhythmias, cardiomyopathies, and valvulopathies, other diagnostic modalities are required. Differentiation between heritable and non-heritable varieties may require testing of relatives. Members of the immediate family are most likely to be affected. For X-linked and recessive types, more extensive genealogical investigation may be required. Medical management, prognosis, and genetic counseling are highly dependent on thorough elucidation.