Updated: 12/21/2019

Dilated Cardiomyopathy

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Snapshot
  • A 60-year-old man presents to his cardiologist for worsening shortness of breath and easy fatigability. He began developing symptoms a few months prior to presentation. His shortness of breath is most significant with exertion and he notes having swollen feet. His medical history includes hypertension, hyperlipidemia, alcohol use disorder. He currently takes hydrochlorothiazide and atorvastatin. On physical exam, an S3 heart sound and a systolic regurgitant murmur is appreciated on cardiac auscultation. An echocardiogram shows markedly dilated ventricles with a reduced ejection fraction.
Introduction
  • Clinical definition
    • a cardiomyopathy characterized by cardiac chamber dilation and systolic dysfunction
  • Epidemiology
    • incidence
      • 90% of all cardiomyopathies
  • Etiology
    • stress
      • Takutsubo cardiomyopathy or broken heart syndrome
        • typically in the context of stressful situations, which can cause increased sympathetic stimulation, resulting in ventricular apical dilatation
    • toxins
      • alcohol abuse
        • toxic damage to myocardium
        • associated thiamine deficiency leads to wet beriberi
      • chronic cocaine use
      • cobalt
      • doxorubicin
    • infectious
      • coxsackie B viral myocarditis
      • Chagas disease (by protozoa Typanosoma cruzi)
        • megacolon
        • megaesophagus
        • South America
    • hereditary
      • muscular dystrophies
      • familial
    • sarcoidosis
    • hemochromatosis
      • this may also cause restrictive cardiomyopathy, but dilated cardiomyopathy is more common
    • peripartum cardiomyopathy
  • Pathogenesis
    • dilated cardiac chambers results in ↓ contractility and ↓ ejection fraction leads to systolic dysfunction
  • Prognosis
    • around 50% of patients die within 2 years from heart failure or arrhythmias
Presentation
  • Symptoms
    • progressive congestive heart failure
      • dyspnea on exertion
      • orthopnea
      • paroxysmal nocturnal dyspnea
      • fatigue
      • pulmonary edema
  • Physical exam
    • cardiac
      • S3 sound
      • systolic regurgitant murmur
    • ascites
    • jugular venous distention
    • pulmonary rales
Imaging
  • Radiography
    • indication
      • for all patients
    • recommend views
      • chest
    • findings
      • heart looks like a balloon
  • Echocardiogram
    • indications
      • for all patients
      • best initial test to assess ejection fraction
    • findings
      • dilated ventricles
      • reduced ejection fraction
Studies
  • Electrocardiography
    • findings
      • may have bundle branch block
      • may have widened QRS
  • Making the diagnosis
    • based on clinical presentation and echocardiography
Differential
  • Restrictive cardiomyopathy
    • distinguishing factors
      • Kussmaul sign on physical exam
      • electrocardiogram with low voltages
  • Hypertrophic cardiomyopathy
    • distinguishing factors
      • echocardiogram with normal ejection fraction
      • S4 gallop on physical exam
Treatment
  • Management approach
    • drugs that lower mortality
      • angiotensin converting enzyme inhibitors or angiotensin receptor blockers
      • β-blockers
      • spironolactone or eplerenone
  • Conservative
    • cessation of alcohol
      • indication
        • for all patients
  • Medical
    • angiotensin converting enzyme inhibitors (ACE inhibitors)
      • indication
        • for all patients
    • β-blockers
      • indication
        • for all patients
      • drugs with mortality benefits
        • metoprolol
        • carvedilol
        • bisoprolol
    • spironolactone or eplerenone
      • indications
        • for all patients
        • decreases work of the heart
  • Operative
    • automatic implantable cardioverter/defibrillator (AICD)
      • indication
        • ejection fraction < 35%
    • biventricular pacemaker
      • indication
        • QRS > 120 ms
        • with a widened QRS, the 2 ventricles are not in synchrony
        • a biventricular pacemaker will resynchronize the 2 ventricles
    • heart transplant
      • indication
        • the only definitive treatment
Complications
  • Heart failure
  • Thromboembolism

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