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Waveform analysis of cardiac electrical activity (ventricular action potential maximum slope)

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

This test measures the steepness of the electrical signal in your heart’s ventricles, which helps assess how well your heart muscle can generate and conduct electrical impulses.

Quick summary

["This test supports evaluation of heart rhythm and conduction disorders."]

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

Key facts at a glance

LOINC
79923-9
Short code
TV A-wave Vmax
Synonyms
TV A-wave Vmax
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
us-doppler
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 This Test Measures

The test analyzes the electrical activity recorded during an electrocardiogram (ECG) or similar cardiac monitoring procedure. It specifically examines the slope of the ventricular action potential—the rapid rise in electrical charge that triggers heart muscle contraction. This slope reflects the heart’s ability to generate and propagate electrical signals efficiently.

Why It Matters in Heart Health

Abnormal slopes in ventricular action potentials can indicate conditions like long QT syndrome, heart block, or other conduction disorders. The slope may also be affected by medications, electrolyte imbalances, or structural heart disease.

Common Conditions Evaluated

This measurement is often used alongside other ECG findings to diagnose or monitor arrhythmias, sudden cardiac death risk, or response to treatments for heart rhythm disorders.

Sample Preparation and Testing Process

No special preparation is needed. The test is typically performed during an ECG or invasive cardiac monitoring (e.g., electrophysiology study). Electrodes are placed on the chest to capture electrical signals, and the waveform slope is analyzed digitally.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Abnormal findings may suggest underlying cardiac electrical dysfunction, which can influence decisions about medications, device implants (e.g., pacemakers), or further diagnostic testing. This test is rarely standalone but often part of a broader evaluation for suspected conduction abnormalities.

Short name

Ventricular Action Potential Max Slope (Waveform Analysis)

Frequently asked questions

What does a ‘normal’ result mean?
A normal result indicates that the heart’s electrical signals are generating and propagating appropriately during the recorded interval. However, individual results depend on the clinical context (e.g., patient symptoms, other test results).
Can lifestyle changes affect this test?
While lifestyle factors like diet, exercise, or stress may influence heart health broadly, they rarely directly alter the measured slope of ventricular action potentials. Your provider will consider overall cardiac health when interpreting results.
Is this test painful or invasive?
No, this test involves only surface electrodes placed on the chest, which are painless and temporary. If performed invasively (e.g., during an electrophysiology study), a local anesthetic may be used, but the procedure is generally well-tolerated.
  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