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dilated cardiomyopathy

Dilated cardiomyopathy is a disorder characterized by dilatation of the cardiac chambers & a reduction in ventricular contractility. Etiology: 1) idiopathic (50%) a) stress cardiomyopathy b) exclusion of CAD, myocarditis, cardiac muscle disease 2) toxic/drug-induced a) alcoholic cardiomyopathy b) doxorubicin c) trastuzumab d) cobalt e) antiretroviral agents - zidovudine - dideoxyinosine (ddI) - dideoxycytosine (ddc) f) phenothiazines g) cocaine h) mercury 3) infectious myocarditis a) viral - coxsackievirus - adenovirus - cytomegalovirus - human immunodeficiency virus (HIV) b) parasitic - toxoplasmosis - trichinosis c) bacterial - diphtheria - rickettsial - Rocky mountain spotted fever -] Q fever - spirochete - leptospirosis - Lyme disease 4) infiltrative & inflammatory disorders a) connective tissue disease - scleroderma b) hypersensitivity myocarditis c) hemochromatosis d) cardiac sarcoidosis e) peripartum state (peripartum cardiomyopathy) - occurs during the last trimester or up to 6 months postpartum [2] - commonly recurs in subsequent pregnancies f) giant cell myocarditis [2] 5) metabolic abnormalities a) nutritional deficiencies - thiamine - selenium - carnitine - taurine b) electrolyte disturbances - hypocalcemia - hypophosphatemia 6) endocrine disorders a) hypothyroidism b) thyrotoxicosis c) acromegaly d) pheochromocytoma 7) tachycardia-induced myocarditis 8) hypertension [5] Pathology: 1) dilatation of cardiac chambers 2) variable hypertrophy 3) symptomatic heart failure often present 4) tricuspid & mitral regurgitation are common 5) atrial & ventricular arrhythmias in 50% 6) high incidence of sudden death 7) left ventricular non-compaction Genetics: - alcoholic cardiomyopathy associated with homozygosity for angiotensin converting enzyme (ACE) deletion allele - defects in LDB3 are a cause of dilated cardiomyopathy - defects in titin are a cause of dilated cardiomyopathy (CMD1G, autosomal dominant) - defects in ABCC9 are a cause of dilated cardiomyopathy (CMD1O), dilated cardiomyopathy with ventricular tachycardia - expression of CAMK2D is significantly increased in patients suffering from dilated cardiomyopathy - defects in LMNA are associated with type 1A - defects in ACTC1 are associated with type 1R - defects in ACTN2 are associated with type 1AA - defects in TNNT2 are associated with type 1D - defects in SCN5A are associated with type 1E - defects in desmin are associated with type 1I - defects in EYA4 are associated with type 1J - defects in CSRP3 are associated with type 1M - defects in TCAP are associated with type 1N - defects in PLN are associated with type 1P - defects in VCL are associated with type 1W - defects in TPM1 are associated with type 1Y - defects in MYH7 are associated with type 1S - defects in thymopoietin-alpha are associated with type 1T - defects in FTKN are associated with type 1X - defects in TNNC1 are associated with type 1Z - defects in TNNI3 are associated with type 2A - defects in SGCD are associated with type 2F - defects in dystrophin are associated with type 3B Special laboratory: 1) echocardiography a) 4 chamber dilation b) ventricular dysfunction c) valvular disease 2) electrocardiogram generally abnormal, but changes are non-specific 3) endomyocardial biopsy of limited value a) hemochromatosis, cardiac sarcoidosis, amyloidosis b) myocarditis Radiology: 1) radionuclide ventriculography - evidence of coronary artery disease 2) cardiac magnetic resonance imaging (CMRi) if cardiac sarcoidosis suspected - late gadolinium enhancement associated with adverse clinical outcomes [7] - 18F-fluorodeoxyglucose (FDG) PET scan if CMRi is negative Differential diagnosis: 1) hypertrophic cardiomyopathy 2) restrictive cardiomyopathy 3) pericardial disease 4) valvular disorders Management: 1) general considerations a) similar to management of heart failure from any cause b) control of total body sodium & water c) vasodilators - preload reduction - afterload reduction - ACE inhibitors are agents of choice d) low-dose beta blockers [2] e) statin may be of benefit, even in non-ischemic heart failure [6] f) counsel all women with previous peripartum cardiomyopathy to avoid pregnancy [2] g) treat peripartum cardiomyopathy with ACE inhibitors, beta-blockers & diuretics [2] 2) specific considerations a) ventricular ectopy (excluding occasional PVCs) - non-sustained ventricular tachycardia is common - high incidence of sudden death - antiarrhythmic agents do not improve survival in non-sustained ventricular ectopy b) anticoagulation - high incidence of mural thrombi c) immunosuppressive therapy for biopsy proven myocarditis - prednisone - azathioprine - cyclosporine d) implantable defibrillators appropriate in about 1/3 of patients [3] 3) evaluation for surgical options a) valvular disease b) coronary artery disease - percutaneous transluminal coronary angioplasty (PTCA) - coronary artery bypass graft (CABG) c) intra-aortic balloon counterpulsation to stabilize a patient before definitive surgical therapy 4) prognosis: a) varies with etiology, chronicity & severity b) spontaneous improvement of ventricular function in 20-40% within 6-12 months of presentation

Specific

cardiac sarcoidosis dilated cardiomyopathy with quadriceps myopathy dilated cardiomyopathy with woolly hair & keratoderma; Carvajal syndrome; palmoplantar keratoderma with left ventricular cardiomyopathy & woolly hair (DCWHK) ischemic cardiomyopathy

General

cardiomyopathy chronic heart disease

Database Correlations

OMIM correlations MORBIDMAP 160760

References

  1. Manual of Medical Therapeutics, 28th ed, Ewald & McKenzie (eds), Little, Brown & Co, Boston, 1995, pg 131-32
  2. Medical Knowledge Self Assessment Program (MKSAP) 11, 14, American College of Physicians, Philadelphia 1998, 2006 - Medical Knowledge Self Assessment Program (MKSAP) 19 Board Basics. An Enhancement to MKSAP19. American College of Physicians, Philadelphia 2022
  3. Journal Watch 22(10):77-78, 2002 Grimm W et al, Implantable defibrillator event rates in patients with idiopathic dilated cardiomyopathy, nonsustained ventricular tachycardia on Holter and a left ventricular ejection fraction below 30%. J Am Coll Cardiol 39:780, 2002 PMID: 11869841 - Kadish A Primary prevention of sudden death using ICD therapy: incremental steps. J Am Coll Cardiol 39:788, 2002 PMID: 11869842
  4. Journal Watch 22(19):155, 2002 Fernandez-Sola J et al Angiotensin-converting enzyme gene polymorphism is associated with vulnerability to alcoholic cardiomyopathy. Ann Intern Med 137:321, 2002 PMID: 12204015
  5. UpToDate 2004 http://www.uptodate.com
  6. Sola S et al, Atorvastatin improves left ventricular systolic function and serum markers of inflammation in nonischemic heart failure. J Am Coll Cardiol 2006, 47:332 PMID: 16412856 - Ramasubbu K and Mann DL The emerging role of statins in the treatment of heart failure. J Am Coll Cardiol 2006, 47:342 PMID: 16412858
  7. Eichhorn C, Koeckerling D, Reddy RK et al Risk Stratification in Nonischemic Dilated Cardiomyopathy Using CMR Imaging: A Systematic Review and Meta-Analysis. JAMA. 2024 Sep 19:e2413946. PMID: 39298146 https://jamanetwork.com/journals/jama/fullarticle/2823869