QRS Patterns - ECG

The description of waves in QRS complexes is actually quite easy. There are just some rules that should be followed.

  1. Bigger amplitudes are marked with big letters and vice versa
  2. If the QRS complex starts with a negative wave, we mark it as Q (q). There can be only one Q (q) in the complex
  3. Positive waves are always marked as R (r)
  4. Negative wave following a positive wave is always marked as S (s)
  5. If there are more positive waves, then the first is marked as R (r), the second R' (r'), the third R''(r''), etc.


QRS Patterns - ECG

Some clinical significance can have the following patterns:

  • rSr' occurs in V1 lead in incomplete RBBB
  • rSR' occurs in V1 lead in complete RBBB
  • QS located in more leads can be related to a post-infarction scar
  • QS or rS in V1 combined with RsR' in V6 is typical for LBBB


Jiri Stefanek, MD  Author of texts: Jiri Stefanek, MD
 Contact: jiri.stefanek@seznam.cz
 Sources: basic text sources