In its simplest form, cardiomyopathy (CMP) can be defined as a cardiac disorder involving myocardial dysfunction. Though there are various formal definitions of CMP in the literature, the two major ones are from the World Health Organization (WHO) and from the American Heart Association (AHA). The WHO definition is more clinical, while the AHA definition is more molecular and scientific in its delineation. For the purpose of this chapter, we will follow the simpler definition by WHO as it lends itself well to the echocardiographic evaluation of cardiomyopathies.
Cardiomyopathies can also be defined by their etiology, as was done also by the WHO task force in 1995. Since the etiology may not always be obvious, such as in many cases of dilated CMP, this classification is also less useful when discussing the general principles of echocardiographic diagnosis of CMP. The various types of cardiomyopathies, as classified by WHO, are listed in Table 14.1. Each type of CMP can have various etiologies, the discussion of which is beyond the scope of this chapter (see suggested reading list for further information). The various etiologies are nonetheless listed in Table 14.2. Table 14.3 demonstrates the key elements in the echocardiographic evaluation of a patient with a CMP.
Table 14.1. The WHO Classification of Cardiomyopathies |Favorite Table|Download (.pdf)
Table 14.1. The WHO Classification of Cardiomyopathies
Arrhythmogenic right ventricular CMP (dysplasia)
Other unclassified cardiomyopathies
Table 14.2. Partial Listing of Etiologies of Cardiomyopathies |Favorite Table|Download (.pdf)
Table 14.2. Partial Listing of Etiologies of Cardiomyopathies
Type of CMP
Idiopathic (mostly genetic)
End-stage valvular heart disease
End-stage hypertensive heart disease
Infectious (viral myocarditis, Chagas, bacterial, etc.)
Toxic/metabolic (chemotherapy, alcoholic, cocaine, etc.)
Rheumatologic (SLE, scleroderma)
Endocrine disorders (diabetes, thyroid disease, etc.)
Neuromuscular diseases (Duchenne's, myotonic dystrophy, etc.)
Electrolyte abnormalities (hypocalcemia, hypophosphatemia, etc.)
Nutritional deficiencies (thiamine, carnitine, etc.)
Infiltrative diseases (usually end-stage)
Infiltrative (amyloidosis, sarcoidosis, etc.)
Storage diseases (hemochromatosis, glycogen storage diseases, etc.)
Isolated LV noncompaction
LV apical ballooning syndrome
Table 14.3. The Key Elements in the Echocardiographic Evaluation of a Patient with a CMP |Favorite Table|Download (.pdf)
Table 14.3. The Key Elements in the Echocardiographic Evaluation of a Patient with a CMP
Assessment of chamber sizes and mass
Left ventricular and left atrial dilatation
Right ventricular dilatation, either primarily or from pulmonary hypertension
Increased cardiac mass and hypertrophy
Assessment of valvular function and valve apparatus
Tricuspid regurgitation, usually secondary from pulmonary hypertension
Mitral valve regurgitation, either due to primary dysfunction of the ...
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