R wave

R wave Overview

The R wave is the first upward deflection after the P wave. The R wave represents early ventricular depolarisation

ECG basics: waves, segments and intervals LITFL ECG library

Abnormalities of the R wave

There are three key R wave abnormalities:

  1. Dominant R wave in V1
  2. Dominant R wave in aVR
  3. Poor R wave progression

1. Dominant R wave in V1

Causes of Dominant R wave in V1

Examples of Dominant R wave in V1

Normal paediatric ECG (2 yr old)
Normal paediatric ECG R wave

Right Ventricular Hypertrophy (RVH)
Right Ventricular Hypertrophy (RVH)

Right Bundle Branch Block
Right Bundle Branch Block RBBB

Right Bundle Branch Block MoRRoW
Right Bundle Branch Block RBBB MoRRoW

Posterior MI
Posterior MI R wave

Wolff-Parkinson-White (WPW) Type A
Wolff-Parkinson-White (WPW) Type A R wave

Leads V1 and V3 reversed
Leads V1 and V3 reversed R wave

Muscular dystrophy
Muscular dystrophy R wave


2. Dominant R wave in aVR


Examples of Dominant R wave in aVR

Poisoning with sodium-channel blocking drugs
Poisoning with sodium-channel blocking drugs
  • Causes a characteristic dominant terminal R wave in aVR
  • Poisoning with sodium-channel blocking agents is suggested if:
    • R wave height > 3mm
    • R/S ratio > 0.7

Dextrocardia
Dextrocardia R wave

This ECG shows all the classic features of dextrocardia:

  • Positive QRS complexes (with upright P and T waves) in aVR
  • Negative QRS complexes (with inverted P and T waves) in lead I
  • Marked right axis deviation
  • Absent R-wave progression in the chest leads (dominant S waves throughout)

Left arm/right arm lead reversal
Lead-reversal-590x208

The most common cause of a dominant R wave in aVR is incorrect limb lead placement, with reversal of the left and right arm electrodes. This produces a similar pattern to dextrocardia in the limb leads but with normal R-wave progression in the chest leads. With LA/RA lead reversal:

  • Lead I becomes inverted
  • Leads aVR and aVL switch places
  • Leads II and III switch places

Ventricular Tachycardia
Ventricular Tachycardia R wave 2

3. Poor R wave progression

Poor R wave progression is described with an R wave ≤ 3 mm inV3 and is caused by:

  • Prior anteroseptal MI
  • LVH
  • Inaccurate lead placement
  • May be a normal variant
PRWP

Note that absent R wave progression is characteristically seen in dextrocardia (see previous ECG).


ECG Library Basics

LITFL Further Reading

Advanced Reading

ECG LIBRARY 700

ECG LIBRARY

Electrocardiogram

Emergency physician MA (Oxon) MBChB (Edin) FACEM FFSEM with a passion for rugby; medical history; medical education; and informatics. Asynchronous learning #FOAMed evangelist. Co-founder and CTO of Life in the Fast lane | Eponyms | Books | vocortex |

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