Cardiology Question 38 Instructor

What is the definition and the causes of dilated cardiomyopathy?

Primary myocardial failure in the absence of underlying coronary, valvular, or pericardial disease.

Causes include:

1. Toxins
   • Ethanol
   • Chemotherapy agents e.g. anthracyclines(adriamycin), cyclophosphamide
   • Heavy metals (cobalt, lead, mercury)
   • Cocaine, Catecholamines
   • Antiretroviral agents
   • Radiation
   • Psychothreapeautic drugs (tricyclic, quadricyclic, phenothiazine)
2. Metabolic abnormalities
   • Nutritional deficiencies (thiamine, selenium, carnitine, kwashiorkor)
   • Endocrine (hyper/hypothyroidism, acromegaly, Cushing’s, pheochromocytoma, diabetes)
   • Electrolyte abnormalities (Uremia, Hypokalemia, hypomagnesemia, Hypocalcemia/phosphatemia)
3. Infectious
   • Viral (Coxsackie B, CMV, HIV)
   • Rickettsia
   • Diphtheria
   • Mycobacteria
   • Fungal
   • Parasitic(toxoplasmosis, trichinosis, Chagas’)
4. Inflammatory
   • Collagen vascular(scleroderma, lupus, dermatomyositis)
   • Hypersensitivity
   • Sarcoidosis
   • Granulomatous disease e.g. Wegener’s granulomatosis
   • Giant cell arteritis
   • Peripartum (1 month before and 5 months after)
5. Neuromuscular syndromes
   • Duchenne’s
   • Facioscapulohumeral muscular dystrophy
   • Erb’s limb-girdle dystrophy
   • Myotonic dystrophy
   • Friedrich’s ataxia
6. Familial cardiomyopathies
7. Neoplasms
8. CAD with diffuse epicardial coronary-artery disease (if CAD is not excluded as an etiology)

In North America, the most common causes are:

1. CAD
2. Post-viral myocarditis
3. Alcoholic cardiomyopathy