Clinical Notes : Cardiology

118. ECG - Pericardial Effusion

ECG - Pericardial Effusion


  • Initially the ECG feature are those of Pericarditis

  • Later, the ECG feature of massive pericarial effusion are :

    • Low QRS voltage

    • Tachycardia

    • Electrical alternans


Massive Pericardial Effusion


Low QRS Voltage

  • Low voltage is produced by…

    • The “damping” effect of increased layers of fluid, fat or air between the heart and the recording electrode.

    • Loss of viable myocardium.

    • Diffuse infiltration or myxoedematous involvement of the heart.

  • Other causes of low voltage include:

    • Fluid

      • ​Pleural effusion

    • Fat

      • Obesity

    • Air

      • Emphysema

      • Pneumothorax

    • Infiltrative / Connective Tissue Disorders

      • Myxoedema

      • Infiltrative myocardial diseases — i.e. restrictive cardiomyopathy due to amyloidosis, sarcoidosis, haemochromatosis

      • Constrictive pericarditis

      • Scleroderma

    • Loss of viable myocardium

      • Previous massive MI

      • End-stage dilated cardiomyopathy


Electrical Alternans

  • consecutive, normally-conducted QRS complexes alternate in height

  • the heart swings backwards and forwards within a large fluid-filled pericardium


Refer A+E


1. Life in the Fast Lane

Austalian Emergency Medicine website. 


Ireland notes.png

CPD Quiz and Certificate

This activity attracts 1,0 CPD point

118. ecg pericardial effusion.jpg

Scroll down the box above to view its entire content

All users who successfully complete the quiz are e-mailed a copy of their personalised CPD certificate.