Dilated Cardiomyopathy

What is it?

Dilated cardiomyopathy is defined by an ejection fraction (EF) of less than 40% in the presence of increased left ventricular end-diastolic volume.

Dilated cardiomyopathy can affect one or all four cardiac chambers and does not involve myocardial hypertrophy. As the chamber enlarges, the myocardial fibrils overstretch and their ability to effectively contract is impaired.

The mortality rate for dilated cardiomyopathy is 50% within five years of diagnosis. Death is often sudden and attributed to ventricular dysrhythmias, stroke, or progressive heart failure

The weakened and stretched myocardial fibers cause a decreased CO, resulting in backflow and pulmonary, and venous congestion.

Causes
  • MI
  • Congenital or aquired structural cardiac defects
  • Chronic tachycardia
  • Peripartum cardiomyopathy
  • Cardiotoxic agents (chemo, ETOH, drugs)
  • Thyroid disorders
  • Connective tissue disorders
Signs & Symptoms
  • General
    • Chronic fatigue
    • Weakness
    • Weight gain
    • Dizziness
    • Syncope
    • Impotence
    • Insomnia
  • Pulmonary
    • Dyspnea on exertion
    • Orthopnea
    • Paroxysmal nocturnal dysnpea
    • Cough
    • Crackles
    • Tachypnea
  • Cardiac
    • Palpitations
    • Chest pain
    • S3/S4, systolic murmur
Diagnostics
  • ECHO
    • Evaulates chamber size and contractility, as well as EF
    • EF less than 40% indicates systolic dysfunction
    • EF less than 15% is common in severe cases
  • Chest X-Ray
    • May reveal chamber enlargement, pulmonary congestion, and PE
  • ECG
    • May demonstrate LBBB, which is a common abnormality with dilated LV.
    • Sinus tachycardia
    • A-fib
    • Ventricular dysrhtyhmias
Treatment
  • Possible placement of ICD to manage lethal dysrhythmias