Cardiomyopathy: An Overview

Overview

Cardiomyopathy describes a group of disorders that affect the heart muscle (the myocardium). They were previously classified as dilated, restricted, and hypertrophic, but this has been abandoned due to the large degree of overlap between them.

Instead, they are classified as:

• Primary cardiomyopathies – disease process originates in the myocardium itself:
  • Genetic cardiomyopathies:
    • Hypertrophic obstructive cardiomyopathy (HOCM)
    • Arrhythmogenic right ventricular cardiomyopathy (ARVC)
    • Ion channelopathies including long QT syndrome
  • Mixed cardiomyopathies:
    • Dilated cardiomyopathy
    • Restrictive cardiomyopathy
  • Acquired cardiomyopathies:
    • Stress cardiomyopathy (Takotsubo cardiomyopathy)
    • Myocarditis
    • Peripartum cardiomyopathy
• Secondary cardiomyopathies – disease process originates outside of the myocardium:
  • Infective causes:
    • An example cause is coxsackie B virus
  • Metabolic causes:
    • An example cause is haemochromatosis
  • Endocrine causes::
    • Example causes are acromegaly, thyrotoxicosis, and diabetes mellitus
  • Toxic causes:
    • Example causes are alcohol and doxorubicin
  • Infiltrative causes:
    • An example cause is amyloidosis
  • Autoimmune and inflammatory causes:
    • Such as systemic lupus erythematosus
    • Such as sarcoidosis
  • Neuromuscular causes:
    • Example causes are muscular dystrophies and Friedrich’s ataxia
  • Cardiomyopathy secondary to nutritional deficiency:
    • An example cause is vitamin B1 (thiamine) deficiency