Video Courses Articles
Video Courses Articles For Institutions Log In GET STARTED

About us | Help


The ECG from First Principles

The basic scientific principles underlying the generation of the 12 lead ECG readout are comprehensible. Conduction of depolarization and regional cellular repolarization in the heart generate a fluctuating voltage at the center of the chest. The galvanometer at the heart of the ECG measures and reports this voltage.

2.0 x AMA PRA Category 1 Credits™
Available on the Pro Plan



In this course, we teach you the basic science underlying the generation of the 12 lead ECG readout. We explain how the conduction of cardiac depolarization and the pattern of cellular repolarization during the cardiac cycle generate a voltage of fluctuating magnitude and direction at the center of the chest. We show you how the ECG, a galvanometer, records the magnitude and direction of this voltage. We explain Einthoven’s law and Einthoven’s triangle. We explain the nature of Wilsons central terminal. We explain the difference between the bipolar frontal leads and the unipolar chest leads.


Planner and Author: Dr John Seery MB PhD

  • Consultant Physician at St. Vincent's University Hospital, Dublin, Ireland
  • Lecturer at the School of Medicine and Medical Science, University College Dublin, Ireland
  • Studied medicine at the University of Cambridge, United Kingdom
  • A Natural Sciences graduate of Trinity College Dublin, Ireland
  • PhD in Cell Biology from University College London, United Kingdom

Planner: Dr Karen Strahan PhD (University of Cambridge), Head of Editorial
Planner: Tommy O'Sullivan, CME Manager

Estimated Time to Complete

2.0 hours

Target Audience

  • Physicians
  • Nurses
  • Nurse Practitioners
  • Physician Assistants
  • Paramedics

Learning Objectives

Upon successful completion of this activity, you will be able to:

  • Explain the basic scientific principles underlying the generation of the 12 lead ECG
  • Explain the difference between the unipolar precordial leads and the bipolar frontal leads
  • Explain Einthoven’s law and Einthoven’s triangle
  • Identify abnormal axes of cardiac depolarization events based on basic vector principles.
  • Develop your knowledge and understanding of the ECG based on the principles learned in this course

Course Content

  • Introduction
  • A Disastrous Guess
  • Electricity 1
  • Electricity 2
  • Electricity 3
  • Electricity 4
  • The Heart as a Battery 1
  • The Heart as a Battery 2
  • The Heart in a Circuit
  • Einthovens Law
  • Einthovens Triangle
  • Why Three Limb Leads?
  • Unipolar Versus Bipolar Leads
  • Wilsons Central Terminal
  • The Unipolar Chest Leads
  • Augmented Vector Leads
  • Final Thoughts
  • Quiz

Release date


Expiration date


Instructions for Participation

Participants must complete the online activity during the valid period as noted above.
Follow these steps:

  1. View videos in sequence
  2. Complete quiz
  3. Complete the activity evaluation form to provide feedback for continuing education purposes and for the development of future activities
  4. Download the Certificate of Completion

Relevant Financial Disclosures

Acadoodle adheres to the ACCME's Standards for Integrity and Independence in Accredited Continuing Education. Any individuals in a position to control the content of a CE activity, including faculty, planners, reviewers or others are required to disclose all relevant financial relationships with ineligible entities (commercial interests). All relevant conflicts of interest have been mitigated prior to the commencement of the activity.

Planners and faculty for this activity have no relevant financial relationships with commercial interests to disclose.


Waller AD. A demonstration on man of electromotive changes accompanying the heart’s beat. J Physiol. 1887;8(5):229-34.

Einthoven W. Die galvanometrische Registrirung des menschlichen Elektrokardiogramms, zugleich eine Beurtheilung der Anwendung des Capillar-Elektrometers in der Physiologie. Pflügers Arch ges Physiol. 1903; 99: 472-80.

Wilson FN et al. Electrocardiograms that represent the potential variations of a single electrode. Am Heart J. 1934; 9: 447-58.

Wiggers CJ. Willem Einthoven (1860 – 1927): Some Facets of his Life and Work. Circ Res. 1961;9:225-34.

ACCME Accreditation Statement

Acadoodle, Ltd is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians.

Credit Designation Statement

AMA Physician’s Recognition Award

Acadoodle, Ltd designates this enduring material activity for a maximum of 2.0 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity.

DisclaimerPrivacy PolicyTerms of UseData Deletion© Acadoodle 2024