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

About us | Help


Tachycardia: ECG Basics

On completing this course, you will have acquired a knowledge of the fundamental principles applied in the analysis and diagnosis of tachycardia on the ECG. You will understand the clinically important distinction between a supraventricular tachycardia and a ventricular tachycardia.

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



In this course, we define important terms used in the description and analysis of a tachycardia on the ECG. We explain the difference between a supraventricular tachycardia and a ventricular tachycardia. We explain the meaning of the term ‘axis’ when used in the context of ECG analysis. You will learn how to determine the ECG axis of an event in the cardiac cycle, a key skill in tachycardia diagnosis. You will learn how to identify junctional and atrial tachycardia on the ECG. You will acquire the fundamental clinical skill of accurately identifying sinus tachycardia on the ECG.


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

1.0 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 significance of the qrs duration in the analysis of a tachycardia on the ECG
  • Define important terms used in the description of a tachycardia on the ECG
  • Explain the concept of ‘axes’ on the ECG 
  • Determine the axes of major events during the cardiac cycle from analysis of the ECG
  • Diagnose junctional tachycardia on the ECG
  • Diagnose atrial tachycardia on the ECG
  • Use appropriate terminology in the description of a tachycardia on the ECG
  • Identify sinus tachycardia on the ECG

Course Content

  • Introduction
  • Frontal Heart Schematic
  • Defining Important Terms
  • Defining SVT & VT
  • The QRS Duration
  • The Concept of Axes
  • The Determination of Axes
  • Enhanced Automaticity
  • Sinus Tachycardia
  • Junctional Tachycardia
  • Atrial Tachycardia
  • Quiz
  • Essential Reading

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. Read the papers on the essential reading list
  3. Complete the quiz
  4. Complete the activity evaluation form to provide feedback for continuing education purposes and for the development of future activities
  5. 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.


Garcia T and Miller G. (2004) Arrhythmia Recognition: The Art of Interpretation. 1st Edition, Jones & Bartlett Learning.

Rosen KM. Junctional Tachycardia. Mechanisms, Diagnosis, Differential Diagnosis, and Management. Circulation. 1973;47(3):654-64.

Kistler PM et al. P wave morphology in focal atrial tachycardia: development of an algorithm to predict the anatomic site of origin. J Am Coll Cardiol. 2006;48(5):1010-7.

Buttà C et al. Electrocardiographic Diagnosis of Atrial Tachycardia, P-Wave Morphology, and Differential Diagnosis with Other Supraventricular Tachycardias. Ann Noninvasive Electrocardiol. 2015;20(4):314-27.

Additional Reading

Antzelevitch C and Burashnikov A. Overview of Basic Mechanisms of Cardiac Arrhythmia. Card Electrophysiol Clin. 2011;3(1):23-45.

Tang CW et al. Use of P wave Configuration During Atrial Tachycardia to Predict Site of Origin. J Am Coll Cardiol. 1995;26(5): 1315-24

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 1.0 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