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Cardiomyopathy (literally "heart muscle disease") is the measurable deterioration for any reason of the ability of the myocardium (the heart muscle) to contract, usually leading to heart failure. Common symptoms include dyspnea (breathlessness) and peripheral edema (swelling of the legs). Those with cardiomyopathy are often at risk of dangerous forms of irregular heart rate and sudden cardiac death. The most common form of cardiomyopathy is dilated cardiomyopathy.〔Cardiopulmonary Pharmacology for Respiratory Care, Jahangir Moini, Ch.2; page 24〕〔http://www.nhlbi.nih.gov/health/health-topics/topics/cm/types.html〕 Although the term "cardiomyopathy" could theoretically apply to almost any disease affecting the heart, it is usually reserved for "severe myocardial disease leading to heart failure." Cardiomyopathy and myocarditis resulted in 443,000 deaths in 2013, up from 294,000 in 1990. ==Differential diagnosis== Cardiomyopathies are either confined to the heart or are part of a generalized disorder, both often leading to death or progressive heart failure. Other diseases that cause heart muscle dysfunction are excluded, such as coronary artery disease, hypertension, or abnormalities of the heart valves. Earlier, simpler, categories such as intrinsic, (defined as weakness of the heart muscle without an identifiable external cause), and extrinsic, (where the primary pathology arose outside the myocardium itself), became more difficult to sustain. For example, as more external causes were recognized, the intrinsic category became smaller. Alcoholism, for example, has been identified as a cause of dilated cardiomyopathy, as has drug toxicity, and certain infections (including Hepatitis C). On the other hand, molecular biology and genetics have given rise to the recognition of various genetic causes, increasing the intrinsic category. For example, mutations in the cardiac desmosomal genes as well as in the DES gene may cause arrhythmogenic right ventricular cardiomyopathy (ARVC). At the same time, a more clinical categorization of cardiomyopathy as 'hypertrophied', 'dilated', or 'restrictive', became difficult to maintain when it became apparent that some of the conditions could fulfill more than one of those three categories at any particular stage of their development.The current American Heart Association definition divides cardiomyopathies into primary, which affect the heart alone, and secondary, which are the result of illness affecting other parts of the body. These categories are further broken down into subgroups which incorporate new genetic and molecular biology knowledge. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Cardiomyopathy」の詳細全文を読む スポンサード リンク
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