Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Estimation of the Physical Quantities01:05

Estimation of the Physical Quantities

4.1K
On many occasions, physicists, other scientists, and engineers need to make estimates of a particular quantity. These are sometimes referred to as guesstimates, order-of-magnitude approximations, back-of-the-envelope calculations, or Fermi calculations. The physicist Enrico Fermi was famous for his ability to estimate various kinds of data with surprising precision. Estimating does not mean guessing a number or a formula at random. Instead, estimation means using prior experience and sound...
4.1K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Standardized processing of explanted hearts after stereotactic arrhythmia radiotherapy (Bio-STAR): a STOPSTORM framework and first human findings.

European heart journal open·2026
Same author

DIGIT-HF: Results From the Win Ratio Analyses.

Circulation. Heart failure·2026
Same author

From clinical observation to shared knowledge: the European Heart Journal Case Reports Cases of the year 2025.

European heart journal. Case reports·2026
Same author

Simple ECG features predict successful catheter ablation of idiopathic premature ventricular contractions with an inferior axis.

Journal of electrocardiology·2026
Same author

Artificial intelligence for patient selection in pulsed-field ablation: promise, pragmatism, and the need for standards.

Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology·2026
Same author

Ventricular conduction is a marker for arrhythmic risk in SCN5A-E1784K overlap sodium channel disease.

Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology·2026
Same journal

[Extrasystoles in endurance athletes].

Herzschrittmachertherapie & Elektrophysiologie·2026
Same journal

[AI-Assisted ECG diagnostics : Classical test statistics still apply].

Herzschrittmachertherapie & Elektrophysiologie·2026
Same journal

[Perioperative complications during transvenous pacemaker and defibrillator implantation].

Herzschrittmachertherapie & Elektrophysiologie·2026
Same journal

Herzschrittmachertherapie & Elektrophysiologie·2026
Same journal

[Late complications after atrial fibrillation ablation : Diagnosis and management].

Herzschrittmachertherapie & Elektrophysiologie·2026
Same journal

[Position paper of the German Society of Cardiology-quality criteria for performing catheter ablation of atrial fibrillation: executive summary].

Herzschrittmachertherapie & Elektrophysiologie·2026
See all related articles

Related Experiment Video

Updated: May 30, 2025

Transthoracic Speckle Tracking Echocardiography for the Quantitative Assessment of Left Ventricular Myocardial Deformation
09:05

Transthoracic Speckle Tracking Echocardiography for the Quantitative Assessment of Left Ventricular Myocardial Deformation

Published on: October 20, 2016

19.4K

Determining the QRS axis: visual estimation is equal to calculation.

Johanna Mueller-Leisse1, Giulia Syrbius2, Henrike Aenne Katrin Hillmann2

  • 1Hannover Heart Rhythm Center, Department of Cardiology & Angiology, Hannover Medical School, Carl-Neuberg Str. 1, 30625, Hannover, Germany. mueller-leisse.johanna@mh-hannover.de.

Herzschrittmachertherapie & Elektrophysiologie
|January 27, 2025
PubMed
Summary
This summary is machine-generated.

Visual estimation of the QRS axis using the hexaxial reference system closely correlates with calculated values. This method is accurate enough for most clinical applications involving electrocardiograms (ECGs) and premature ventricular complexes (PVCs).

Keywords:
12-Lead-ECGECG basicsHexaxial reference systemOutflow tract PVCsPVC morphology

More Related Videos

Real-Time Cardiac Mapping with a Noninvasive Imageless Electrocardiographic Imaging System
10:17

Real-Time Cardiac Mapping with a Noninvasive Imageless Electrocardiographic Imaging System

Published on: April 11, 2025

378
Estimating Bilateral Atrial Function by Cardiovascular Magnetic Resonance Feature Tracking in Patients with Paroxysmal Atrial Fibrillation
08:10

Estimating Bilateral Atrial Function by Cardiovascular Magnetic Resonance Feature Tracking in Patients with Paroxysmal Atrial Fibrillation

Published on: July 20, 2022

1.6K

Related Experiment Videos

Last Updated: May 30, 2025

Transthoracic Speckle Tracking Echocardiography for the Quantitative Assessment of Left Ventricular Myocardial Deformation
09:05

Transthoracic Speckle Tracking Echocardiography for the Quantitative Assessment of Left Ventricular Myocardial Deformation

Published on: October 20, 2016

19.4K
Real-Time Cardiac Mapping with a Noninvasive Imageless Electrocardiographic Imaging System
10:17

Real-Time Cardiac Mapping with a Noninvasive Imageless Electrocardiographic Imaging System

Published on: April 11, 2025

378
Estimating Bilateral Atrial Function by Cardiovascular Magnetic Resonance Feature Tracking in Patients with Paroxysmal Atrial Fibrillation
08:10

Estimating Bilateral Atrial Function by Cardiovascular Magnetic Resonance Feature Tracking in Patients with Paroxysmal Atrial Fibrillation

Published on: July 20, 2022

1.6K

Area of Science:

  • Cardiology
  • Medical Imaging
  • Diagnostic Tools

Background:

  • The QRS axis on an electrocardiogram (ECG) is crucial but often estimated crudely.
  • Precise QRS axis determination is valuable for scenarios like pinpointing the origin of premature ventricular complexes (PVCs).
  • Visual estimation using the hexaxial reference system offers a method for more exact QRS axis determination.

Purpose of the Study:

  • To evaluate the correlation between visually estimated QRS axis and mathematically calculated QRS axis.
  • To assess the accuracy of visual QRS axis estimation in patients with outflow tract PVCs.

Main Methods:

  • Analysis of 12-lead ECGs from a PVC database (2012-2020) for outflow tract PVCs.
  • Visual QRS axis determination by two physicians using the hexaxial reference system (±10° accuracy).
  • Calculation of QRS axes using three established voltage-based formulas.

Main Results:

  • Strong correlations were found between visually estimated and calculated QRS axes for both regularly conducted beats (r=0.97-0.98) and PVCs (r=0.94).
  • Estimated QRS axis for regularly conducted beats was 39±40°, and for PVCs was 88±15°.
  • Calculated QRS axes closely matched the visual estimations across all formulas and beat types.

Conclusions:

  • Sophisticated visual estimation of the QRS axis is a reliable method.
  • This visual estimation correlates well with voltage-based calculations.
  • The visual method is sufficient for most clinical purposes in ECG analysis.