Cardiomyopathies

Exam Cram

• Cardiomyopathies are a collection of disorders of the functioning of the cardiac muscle

• Cardiomyopathy can be classified by cause: primary or secondary causes or by phenotype- dilated, restrictive, hypertrophic or Takotsubo

• Dilated is most commonly idiopathic or ischaemic

• Restrictive is commonly caused by sarcoidosis, haemochromatosis or amyloidosis

Cardiomyopathies

Myocarditis refers to acute myocardial inflammation. Cardiomyopathy refers to long term damage to myocardium. 

Cardiomyopathy Classification

Aetiology

• Primary (idiopathic)

• Secondary

Phenotypes

• Dilated

• Restrictive

• Hypertrophic: HOCM

• Takotsubo Cardiomyopathy 

• Ischaemic Cardiomyopathy

• Partum cardiomyopathy

Dilated Cardiomyopathy

Diagnosis (ECHO)

• Enlargement of ventricles with

• Ejection fraction < 40%

Causes

• Primary Idiopathic 40%

• Secondary

  • Myocardial infarction 40% 

  • Genetic 1%

  • Pregnancy

  • Infective myocarditis: Lyme disease

  • Hypertension 

  • Alcohol, Chemotherapy (Trastuzumab)

Prognosis

• Poor

• Progresses to heart failure & End of Life Care 

Restrictive Cardiomyopathy

Diagnosis (ECHO)

• Diastolic dysfunction in non dilated ventricle

Causes (majority secondary)

• Amyloidosis 

• Sarcoidosis 

• Haemochromatosis 

Management

• As per underlying cause

• Congestive Heart Failure (CHF) principles

Hypertrophic: HOCM

• Primarily primary (idiopathic) genetic cause

• Presentation: exercise syncope

• Management

  • Betablockers

  • ICD

Takotsubo Cardiomyopathy 

• Acquired primary cardiomyopathy

• Presentation: post emotional cardiac dysfunction

• Ventricular dysfunction across multiple vascular territories

• Apical most common

Outline

Assessment

History

• Worsening chest pains, exercise tolerance and fevers

• Recent upper respiratory tract infection

Examination

• Heart failure: biventricular

  • Pulmonary oedema

  • Peripheral oedema

Investigations

• Raised troponin

• ECG: widespread TWI

Diagnosis & Classification

Diagnostic criteria: clinical, usually by cardiologist

Differentials

• NSTEMI: has TWI in vascular territories, myocarditis has TWI across multiple territories

• Pericarditis has saddle ST changes

Management

• Cardiology FU: repeat ECHO

• As per Congestive Heart Failure (CHF) principles

• May require heart transplant

References and Resources

1. https://dcmfoundation.org/about-dilated-cardiomyopathy/dilated-cardiomyopathy-causes/?gad_source=1&gclid=CjwKCAiAzvC9BhADEiwAEhtlN_8sLUIdaj7bk7cALevPcFyxhOy0tzLXgm3DZWjnh6OqOs0AXkZuDRoCuY4QAvD_BwE

2. Mahmaljy H, Yelamanchili VS, Singhal M. Dilated Cardiomyopathy. [Updated 2023 Apr 7]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK441911/

3. Brown KN, Pendela VS, Ahmed I, et al. Restrictive Cardiomyopathy. [Updated 2023 Jul 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK537234/

4. Brieler J, Breeden MA, Tucker J. Cardiomyopathy: An Overview. Am Fam Physician. 2017 Nov 15;96(10):640-646. PMID: 29431384.

Links

• Diseases: cardiovascular

• Specialty: cardiology

Written in 2025