Dilated Cardiomyopathy, New Presentation

a) Most common cause in US is ischemic, and thus must rule this out

      - Given concern for balanced ischemia, non-invasive study (e.g. stress echo or myocardial perfusion study) is typically not adequate to rule out CAD

b) Framework for other causes of DCM:

      - Valvular: AS, MR

      - Hypertrophic (can burn out and dilate): HTN, HCM

      - Infectious: viral, rheumatic fever, HIV, Lyme, Chagas

      - Stress: Takosubo, critical illness, peripartum, tachycardia

      - Metabolic: thyroid dz, Cushing's, thiamine deficiency, celiac disease

      - Infiltrative: hemochromatosis, sarcoidosis

      - Autoimmune: SLE, systemic sclerosis, giant cell arteritis

      - Toxic: EtOH, stimulant, chemotherapy, XRT

      - Congenital: muscular dystrophy, non-compaction

c) In patients with MR, it can be difficult to tell whether the MR is the cause of the DCM, or results from dilatation of the LV and mitral valve annulus

      - Central regurgitant jet and large LV suggests that the DCM is primary

      - Presence of valvular calcification or other structural abnormalities suggests that valve pathology is primary

(Christopher Woo MD, 9/3/10)