Chapter 117: Cardiomyopathies and Myocarditis
Cardiomyopathies are primary diseases of heart muscle. Table 117-1 summarizes distinguishing presenting features of the three major types of cardiomyopathy (CMP). Table 117-2 details the comprehensive initial evaluation of suspected cardiomyopathies.
DILATED | RESTRICTIVE | HYPERTROPHIC | |
---|---|---|---|
Ejection fraction (normal >55%) | Usually <30% when symptoms severe | 25–50% | >60% |
Left ventricular diastolic dimension (normal <55 mm) | ≥60 mm | <60 mm (may be decreased) | Often decreased |
Left ventricular wall thickness | Normal or decreased | Normal or increased | Markedly increased |
Atrial size | Increased | Increased; may be massive | Increased |
Valvular regurgitation | Related to annular dilation | Related to endocardial involvement; frequent mitral and tricuspid regurgitation, rarely severe | Related to valve-septum interaction: mitral regurgitation |
Common first symptoms | Exertional intolerance | Exertional intolerance, fluid retention early | Exertional intolerance; may have chest pain |
Congestive symptomsa | Left before right, except right prominent in young adults | Right often dominates | Left-sided congestion may develop late |
Arrhythmia | Ventricular tachyarrhythmia; conduction block in Chagas’ disease, and some familial forms. Atrial fibrillation | Ventricular uncommon except in sarcoidosis, conduction block in sarcoidosis and amyloidosis. Atrial fibrillation | Ventricular tachyarrhythmias; atrial fibrillation |
aLeft-sided symptoms of pulmonary congestion: dyspnea on exertion, orthopnea, paroxysmal nocturnal dyspnea. Right-sided symptoms of systemic venous congestion: hepatic and abdominal distention, discomfort on bending, peripheral edema.
Clinical Evaluation |
Thorough history and physical examination to identify cardiac and noncardiac disordersa Detailed family history of heart failure, cardiomyopathy, skeletal myopathy, conduction disorders and tachyarrhythmias, sudden death History of alcohol, illicit drugs, chemotherapy, or radiation therapya Assessment of ability to perform routine and desired activitiesa Assessment of volume status, orthostatic blood pressure, body mass indexa |
Laboratory Evaluation |
Electrocardiograma Chest radiographa Two-dimensional and Doppler echocardiograma Magnetic resonance imaging to assess myocardial inflammation and fibrosis Chemistry: Serum sodium,a potassium,a calcium,a magnesiuma Fasting glucose (glycohemoglobin in diabetes mellitus) Creatinine,a blood urea nitrogena Albumin,a total protein,a liver function testsa Lipid profile Thyroid-stimulating hormonea Serum iron, transferrin saturation Urinalysis Creatine kinase isoforms Cardiac troponin Hematology: Hemoglobin/hematocrita White blood cell count with differential,a including eosinophils Erythrocyte sedimentation rate |
Initial Evaluation When Specific Diagnoses Are Suspected |
DNA sequencing for genetic disease; panel selection based on phenotype Titers for infection in presence of clinical suspicion: Acute viral (e.g., coxsackievirus, echovirus, influenza) Human immunodeficiency virus Chagas’ disease, Lyme disease, toxoplasmosis Coronary angiography in pts with angina who are candidates for interventiona Serologies for active rheumatologic disease Endomyocardial biopsy including sample for electron microscopy when suspecting specific diagnosis with therapeutic implications Screening for sleep-disordered breathing |
aLevel I Recommendations from ACC/AHA Practice Guidelines for Chronic Heart Failure in the adult.
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Citation
Kasper, Dennis L., et al., editors. "Chapter 117: Cardiomyopathies and Myocarditis." Harrison's Manual of Medicine, 20th ed., McGraw Hill Inc., 2020. harrisons.unboundmedicine.com/harrisons/view/Harrisons-Manual-of-Medicine/623029/all/Chapter_117:_Cardiomyopathies_and_Myocarditis.
Chapter 117: Cardiomyopathies and Myocarditis. In: Kasper DLD, Fauci ASA, Hauser SLS, et al, eds. Harrison's Manual of Medicine. McGraw Hill Inc.; 2020. https://harrisons.unboundmedicine.com/harrisons/view/Harrisons-Manual-of-Medicine/623029/all/Chapter_117:_Cardiomyopathies_and_Myocarditis. Accessed December 9, 2024.
Chapter 117: Cardiomyopathies and Myocarditis. (2020). In Kasper, D. L., Fauci, A. S., Hauser, S. L., Longo, D. L., Jameson, J. L., & Loscalzo, J. (Eds.), Harrison's Manual of Medicine (20th ed.). McGraw Hill Inc.. https://harrisons.unboundmedicine.com/harrisons/view/Harrisons-Manual-of-Medicine/623029/all/Chapter_117:_Cardiomyopathies_and_Myocarditis
Chapter 117: Cardiomyopathies and Myocarditis [Internet]. In: Kasper DLD, Fauci ASA, Hauser SLS, Longo DLD, Jameson JLJ, Loscalzo JJ, editors. Harrison's Manual of Medicine. McGraw Hill Inc.; 2020. [cited 2024 December 09]. Available from: https://harrisons.unboundmedicine.com/harrisons/view/Harrisons-Manual-of-Medicine/623029/all/Chapter_117:_Cardiomyopathies_and_Myocarditis.
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