Restrictive Cardiomyopathy

ECG Features of Restrictive Cardiomyopathy
  • Low voltage QRS complexes
  • Non-specific ST segment / T wave changes
  • Bundle branch blocks
  • Atrioventricular block (3rd degree AV block may occur in sarcoidosis)
  • Pathological “pseudo-infarction” Q waves
  • Atrial and ventricular dysrhythmias


Restrictive cardiomyopathy is the least common form of cardiomyopathy. It occurs in the advanced stages of myocardial infiltrative disease — e.g. due to haemochromatosis, amyloidosis or sarcoidosis.

  • Diffuse myocardial infiltration leads to low voltage QRS complexes.
  • Atrial fibrillation may occur due to atrial enlargement; ventricular arrhythmias are also common
  • Infiltration of the cardiac conducting system (e.g. due to septal granuloma formation in sarcoidosis) may lead to conduction disturbance — e.g. bundle branch blocks and AV block.
  • Healing granulomas in sarcoidosis may produce “pseudo-infarction” Q waves

Example ECG
ECG low QRS voltage

ECG of a patient with restrictive cardiomyopathy, demonstrating:

  • Low voltage QRS complexes
  • Widespread flattening of T waves


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Emergency Physician in Prehospital and Retrieval Medicine in Sydney, Australia. He has a passion for ECG interpretation and medical education | ECG Library |

MBBS (UWA) CCPU (RCE, Biliary, DVT, E-FAST, AAA) Adult/Paediatric Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Editor-in-chief of the LITFL ECG Library. Twitter: @rob_buttner

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