Why is there no wave for atrial repolarisation in the electrocardiogram?

While atrial repolarisation exists, you actually can't see it in the ECG! I can draw you a diagram of a normal cardiac cycle: this is the P wave, that you'll know represents the DEpolarisation of the atria. The QRS complex here represents the huuuuge wave of ventricular depolarisation, and then the T wave is the ventricles REpolarising.

So when does atrial repolarisation happen in the cardiac cycle? It happens very shortly after its contraction! Almost immediately after a heart muscle depolarises and contracts, it repolarises again! So the atrial repolarisation - what's called a Ta wave - is actually ABSORBED by the QRS complex, so you don't end up seeing it on an ECG!

SM
Answered by Scott M. Human Biology tutor

5866 Views

See similar Human Biology A Level tutors

Related Human Biology A Level answers

All answers ▸

What are the stages of meiosis?


State three differences between the structure of DNA and the structure of RNA


Explain how voltage-gated sodium ion channels on the membranes of neurones generate an action potential.


describe the types of blood vessels of the circulatory system and the direction in which they transport the blood.


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences