Cardiac Rhythms | Lessons, Drills, Quizzes

Cardiac Rhythms and ECG Overview

Study of a patient's cardiac rhythms using an ECG may indicate normal or abnormal conditions. Abnormal rhythms are called arrhythmia or sometimes, dysrhythmia. Arrhythmia is an abnormally slow or fast heart rate or an irregular cardiac rhythm. During a single heart beat, several electrical events occur. These events are part of an ECG tracing and are called P, Q, R, S, T and U.

The first movement of the ECG tracing (usually upwards) is the P wave, indicating electrical activity that triggers atrial contraction. The QRS complex indicates ventricular depolarization and contraction and are usually of greater amplitude than the P wave. The PR interval indicates the electrical signal traveling from the sinus node to the ventricles.

T wave is normally a smaller (than QRS) upwards waveform, indicating ventricular repolarization.

Cardiac Rhythm Strip Reference Guide

Our rhythm strips guide provides information on essential dysrhythmia categories:

Atrial
- Premature Atrial Contractions
- Atrial Flutter
- Atrial Fibrillation
- Multifocal Atrial Tachycardia
- Wandering Atrial Pacemaker
Junctional
- Junctional Rhythm
- Junctional Tachycardia
- Premature Junctional Contraction
- Supraventricular Tachycardia
Ventricular
- Premature Ventricular Contractions (several type of)
- Accelerated Idioventricular Rhythm
- Ventricular Fibrillation
- Monomorphic Ventricular Tachycardia
- Polymorphic Ventricular Tachycardia
Heart Blocks
- First Degree Heart Block
- Second Degree Heart Block, Type 1 - Mobitz I
- Second Degree Heart Block, Type 2 - Mobitz II
- Third Degree Heart Block
Sudden Arrhythmic Death Syndrome

For each cardiac rhythm category we provide one or more ECG tracings. A synopsis of the cardiac rhythm (dysrhythmia) is provided and electronic calipers can be used to study each tracing.

Cardiac Rhythms Strip Guide

Cardiac Rhythms - Training Tools

Learn about cardiac rhythms using these tools:

Cardiac Rhythm Strips Drills
Rhythms Quiz
ECG Guide
Basic Training Lessons

Each of these training methods is summarized below.

Authors and Sources

Authors and Reviewers

ECG heart rhythm modules: Thomas O'Brien.
ECG monitor simulation developer: Steve Collmann
12 Lead Course: Dr. Michael Mazzini, MD.
Spanish language ECG: Breena R. Taira, MD, MPH
Medical review: Dr. Jonathan Keroes, MD
Medical review: Dr. Pedro Azevedo, MD, Cardiology
Last Update: 11/8/2021

Sources

Electrocardiography for Healthcare Professionals, 6th Edition Kathryn Booth and Thomas O'Brien
ISBN10: 1265013470, ISBN13: 9781265013479
McGraw Hill, 2023
Rapid Interpretation of EKG's, Sixth Edition
Dale Dublin
Cover Publishing Company
EKG Reference Guide
EKG.Academy
12 Lead EKG for Nurses: Simple Steps to Interpret Rhythms, Arrhythmias, Blocks, Hypertrophy, Infarcts, & Cardiac Drugs
Aaron Reed
Create Space Independent Publishing
Heart Sounds and Murmurs: A Practical Guide with Audio CD-ROM 3rd Edition
Elsevier-Health Sciences Division
Barbara A. Erickson, PhD, RN, CCRN
The Virtual Cardiac Patient: A Multimedia Guide to Heart Sounds, Murmurs, EKG Jonathan Keroes, David Lieberman
Publisher: Lippincott Williams & Wilkin)
ISBN-10: 0781784425; ISBN-13: 978-0781784429
Project Semilla, UCLA Emergency Medicine, EKG Training Breena R. Taira, MD, MPH
ECG Reference Guide
PracticalClinicalSkills.com