Chapter 57: Classification of Cardiomyopathies
Which of the following is true about the American Heart Association (AHA) classification of cardiomyopathies?
A. Primary cardiomyopathies are limited to cardiomyopathies with systolic dysfunction
B. Secondary cardiomyopathies are cardiomyopathies that are associated with a systemic, multiorgan disorder
C. A patient with hypertrophic cardiomyopathy (HCM) that results in a dilated phenotype would be considered to have a mixed cardiomyopathy
D. Ion channel disorders are not considered to be primary cardiomyopathies
The answer is B. (Hurst’s The Heart, 14th Edition, Chap. 57) The AHA classification emphasizes the mechanism for cardiomyopathy, not the morphology.1 Under the AHA classification, cardiomyopathies are not limited to disorders of systolic dysfunction (option A). Cardiomyopathies were divided into two major groups based on predominant organ involvement. The primary cardiomyopathies were those solely or predominantly confined to heart muscle. The primary cardiomyopathies were further categorized into genetic, acquired, and mixed varieties and represented the novelty of the AHA classification (Figure 57-1). Ion channel disorders are included as genetic cardiomyopathies (Figure 57-1) (option D). Thus, a patient with HCM would have a primary genetic cardiomyopathy (option C). The secondary cardiomyopathies showed pathologic myocardial involvement as part of systemic (multiorgan) disorders (option B).
FIGURE 57-1. AHA classification of cardiomyopathy. (Reproduced with permission from Maron BJ, Towbin JA, Thiene G, et al. Contemporary definitions and classification of the cardiomyopathies: an American Heart Association Scientific Statement from the Council on Clinical Cardiology, Heart Failure and Transplantation Committee; Quality of Care and Outcomes Research and Functional Genomics and Translational Biology Interdisciplinary Working Groups; and Council on Epidemiology and Prevention, Circulation. 2006 Apr 11;113(14):1807-1816.)
Which of the following is not true of the 2008 European Society of Cardiology (ESC) classification of cardiomyopathy?
A. Ion channelopathies are not included in the classification of cardiomyopathies
B. Familial cardiomyopathies are defined by the occurrence of a phenotype in more than one family member that could be caused by the same genetic mutation
C. Arrhythmogenic right ventricular cardiomyopathy (ARVC) is considered a distinct cardiomyopathy, different from dilated cardiomyopathy, HCM, and restrictive cardiomyopathy
D. The genetic basis of cardiomyopathy is emphasized over morphofunctional features in the classification
E. None of the above are true
The answer is D. (Hurst’s The Heart, 14th Edition, Chap. 57). The 2008 ESC classification of cardiomyopathy emphasizes morphofunctional ...