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R-wave amplitude (electrocardiogram, ECG)

Published: August 9, 2026Updated: August 16, 2026

This test measures the height of the R-wave on an electrocardiogram (ECG), a recording of the electrical activity of your heart. It helps assess heart conduction and potential abnormalities in heart rhythm or structure.

Quick summary

["The R-wave amplitude can indicate how well your heart’s electrical signals travel through the heart muscle."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
10020-6
Short code
R' wave Amp L-V5
Synonyms
R' wave Amp L-V5
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ekg
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What Is an R-Wave Amplitude Test Used For?

Doctors may use this measurement to evaluate heart health, especially in diagnosing conditions like heart block, heart muscle disease (cardiomyopathy), or assessing the spread of electrical signals during an ECG. It can also help identify early signs of heart rhythm disorders or structural changes in the heart.

How Is This Test Performed?

You’ll lie down on an exam table with electrodes attached to your chest. A machine records the electrical signals passing through your heart, and the R-wave amplitude is measured from the ECG tracing. No special preparation is needed, but avoid caffeine or nicotine 30 minutes before the test.

What Does an Abnormal R-Wave Amplitude Mean?

Changes in R-wave amplitude can signal different issues, such as delayed conduction (e.g., bundle branch block), heart enlargement, or scarring from past heart damage. A doctor will interpret results in the context of your full ECG and medical history.

Common Causes of Abnormal Results

Variations in R-wave amplitude may occur due to normal aging, differences in body size, or certain heart conditions. For example, a smaller R-wave might indicate a block in the heart’s electrical pathway, while a larger wave could suggest heart enlargement or other structural changes.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

ECG R-wave height

Frequently asked questions

Why might my doctor order an R-wave amplitude test?
Your doctor may order this test if they suspect heart-related issues like heart block, cardiomyopathy, or other conduction abnormalities. It can also be part of a routine ECG to monitor heart health, especially in people with a history of heart disease or those at higher risk for heart rhythm problems.
Is there any preparation needed before this test?
No special preparation is required, but avoid caffeine or nicotine 30 minutes before the test to ensure accurate results. Wear loose clothing and avoid metal jewelry on your chest.
Can R-wave amplitude changes be caused by non-heart-related factors?
Yes, factors like body size, age, or electrode placement can influence R-wave amplitude. However, persistent or abnormal changes warrant further evaluation by a healthcare provider to rule out underlying heart conditions.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy