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INTRODUCTION

The term cardiomyopathy describes a heterogeneous group of diseases that directly alter cardiac structure, impair myocardial function, or alter myocardial electrical properties. Discoveries in molecular genetics and the description of (ion) channelopathies as diseases have prompted periodic revisions of definitions and classifications of cardiomyopathies. The MOGE(S) classification is the most recently proposed and describes the morphofunctional phenotype (M), organ(s) involvement (O), genetic inheritance pattern (G), etiology (E; which includes genetic defect or underlying disease), and functional status (S).1,2 In simple terms, primary cardiomyopathies are diseases that solely or predominantly involve the myocardium and are usually familial in origin; the most common disorders are listed in Table 55-1. Secondary cardiomyopathies include heart muscle diseases associated with specific systemic disorders. Secondary cardiomyopathies often present with morphofunctional phenotypes and hemodynamic findings similar to those of the dilated or restrictive forms of cardiomyopathy. The most common causes of secondary cardiomyopathies are listed in Table 55-2. As a group, cardiomyopathies are the third most common form of cardiac disease encountered in the United States, following coronary (ischemic) heart disease and hypertensive heart disease. Hypertrophic cardiomyopathy is the second most common cause of sudden cardiac death in the adolescent population and the leading cause of sudden death in competitive athletes.3

TABLE 55-1The Primary Cardiomyopathies
TABLE 55-2Common Causes of Secondary Cardiomyopathies

An in-depth discussion of each of the primary familial and secondary cardiomyopathies is beyond the scope of this chapter, and emergency providers are unlikely to make a specific diagnosis in the ED. This chapter discusses selected cardiomyopathies (Table 55-3). Arrhythmogenic ventricular cardiomyopathy is discussed in Chapter 130, “Syncope, Dysrhythmias, and ECG Interpretation in Children.” The cardiomyopathies usually present with signs of systolic and diastolic ventricular dysfunction. The ED evaluation will generally guide the need for urgent treatment, admission, or referral for further diagnostic evaluation.4

TABLE 55-3Features of Selected Cardiomyopathies

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