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Welcome to The EP Lab...

About The EP Lab...

This web site offers a unique perspective for the Allied Health Professional working in the field of Cardiac Electrophysiology. The information found throughout the lab offers a blend of EP facts balanced with the experiences of someone who has worked in the field for 15 years. As the author of The EP Lab, I have sought to provide an online resource that will help Allied Health Professionals gain a better understanding of this exciting, dynamic field.

Many people have asked about the subscription fees associated with this site. I consider this to be an online book that offers similar materials to that which you would find in a printed text. Authors rarely give away books and are compensated for their knowledge and the effort they have put into providing that knowledge to the reader. This site is no different. The subscription costs vary depending upon the number of months you subscribe for. For one month, the cost is $20. If you subscribe for a full year, the cost is $8.33 per month. Below is a list of some of the subject matter covered in The EP Lab.

Cardiac Anatomy & Physiology

The cardiac structure is the environment in which we work. The more you know about the heart, the more effective your skills in the lab will become. This section covers the essential cardiac structures and the role they play in both normal and abnormal cardiac activity. The following sections are found in this section of the site;

The Cardiac Structure

Cardiac Chmabers; Right Atrium, Right Ventricle, Left Atrium, Left Ventricle, Cardiac Base vs Apex

Cardiac Layers; Pericardium, Cardiac Perforation, Epicardial Mapping, Epicardium, Myocardium, Myocardial Tissue Thickness, , Myocardial Fiber Alignment, Endocardium

Cardiac Valves; Atrioventricular Valves - Tricuspid Valve & Mitral Valve, Arterial or Semilunar Valves - Pulmonic & Aortic Valves

Cardiac Circulation; SVC / IVC, RA, RV, RVOT, PA, The Lungs, LA, LV, LVOT, AO, The Coronary Arteries (Image), The Coronary Sinus


Right Atrial Structures:

The Sinus Node, Crista Terminalis (Terminal Crest & Terminal Sulcus), Pectinate Muscles, Right Atrial Appendage, Inter atrial and Intra atrial Pathways, Bachman's Bundle, Atrial Septum, Foramen Ovale / Fossa Ovalis, Limbic Band / Ridge, Coronary Sinus, Thebesian Valve, Eustachion Ridge / Valve, Membranous Septum, Tricuspid Valve, Triangle of Koch, Atrial Ventricular Node (AV Node), Right Atrial Isthmus, Inferior Vena Cava (IVC)

The Right Ventricle

Right Ventricular Structures:

The Inflow Track and Right Ventricle; Tricuspid Valve, Muscular Bands, Papillary Muscles

Right Ventricular Outflow Track; Infundibulum, Pulmonic Valve, Pulmonary Artery


Left Atrial Structures:

Atrial Septum, Bachman's Bundle, Foramen Ovale / Fossa Ovalis, Left Atrial Appendage, Ridge of Marshall, Mitral Isthmus, Mitral Valve,

Pulmonary Veins; Left Superior & Left Inferior, Right Superior * Right Inferior

The Left Ventricle

Left Ventricular Structures:

Mitral Valve, Left Bundle Branches; Left Anterior Bundle, Left Posterior Bundle, Left Ventricular Papillary Muscles; Anterior, Posterior and Lateral, Left Ventricular Outflow Track, Membranous Septum, Limbus Marginalis, Aortic Valve and the three different cusps

The Cardiac
Conduction System

Cardiac Conduction:

Sinus Node, Intra-Atrial Tracks / Bachman's Bundle, AV Node, HIS Bundle, Right Bundle, Left Anterior & Posterior Fascicles, Purkinje Network


The Action Potential:

Phase 0, Phase 1, Phase 2, Phase 3, Phase 4, Transmembrane Potential, Abnormal Automaticity, Differences in Action Potentials, Autonomic Innervation, Sympathetic Tone, Parasympathetic Tone


Cellular Properties:

Automticity, Excitablity & Refractoriness; Image series demonstrating Refractory Periods

The Autonomic
Nervous System

The Autonomic Nervous System:

Sympathetic and Parasympathetic Response


Classification of Antiarrhytmic Drugs:

Class I: Class Ia Medications; Class Ib Medications, Class Ic Medications, Class II, Class III, Class IV, Class V



Electrograms are the language of EP. To become proficient in the lab, you can learn how to push all the buttons on the equipment. To master EP, you must learn to read electrograms. This section contains information that describes everything you need to know to learn the language of the lab.

Electrograms Defined

Electrograms Defined:

A Graph of Voltage over Time, The Isoelectric Line, Grounding the Signal, The Driven Reference, Creating a Zero Potential

Recording Modes

Recording Modes:

Number of Electrodes, Unipolar, Bipolar, The Zero Potential Reference, The Driven Reference

Images showing the difference between unipolar and bipolar electrograms.

Electrode Spacing

Electrode Spacing:

What the different spacing of the electrodes does to a bipolar electrogram, The Surface ECG bipolar electrograms.

(213) 598-4806

Electrogram Filters:

Noise Filter, Notch Filter, High Pass Filter, Low Pass Filter, Band Pass Filter, Common Filter Settings

Image Sequence that demonstrates how adjusting the Band Pass Filter settings affects Surface ECG's, Intracardiac Bipolar and Intracardiac Unipolar Electrograms.

EGM Interpretation

Electrogram Interpretation:

Discussion on the finer points of reading electrograms. This section is under development.

Surface ECG's

Surface Electrocardiograms:

A look at the oldest non-contact unipolar mapping system. This section is under development.

Intracardiac EGM's

Intracardiac Electrograms:

Electrograms recorded from inside the heart. This section takes a look at how to start the interpretive process of understanding what bipolar signals recorded from different catheters tell you.



This section is dedicated to the different procedures performed in the EP Lab.

Setting Up

Setting Up & Patient Prep:

Power Connections: How understanding some of the basic principals of electrical interference can make life easier in the lab.
Skin Prep; What can you do to ensure the best signal quality? A few pointers on good skin prep.
Patch Placement; Knowing where to place the various types of surface patches used in EP and where not to place them can save your lab a great deal of difficulty.

Catheter Placement

Catheter Placement:

Discusses the standard locations for catheter placement during diagnostic EP procedures.

Baseline Measurements

Baseline Measurements:

What are the baseline measurements taken at the start of an EP study and what are the normal values for each. This section under development.


Sinus Node Recovery Time:

Evaluation of the sinus node with normal and abnormal results including corrected SNRT's.

Conduction Study

Conduction Study:

Evaluation of conduction through the AV Node and the His Bundle both antegrade and retrograde, fast pathway refractory period, wenkebach conduction pattern and 2:1 block.

Arrhythmia Induction

Arrhythmia Induction:

Examine the techniques used to induce arrhythmias during EP procedures. Methods include Programmed Stimulation, Burst Pacing, Medication Challenge (Isoproterinal / Isoprel)

Pacing Maneuvers

Pacing Maneuvers:

Explore the various methods that pacing is utilized during electrophysiology procedures. Techniques include verification of presence of a concealed pathway, anti-tachycardia pacing, pace entrainment, pace mapping and advancing the "A" to differentiate arrhythmias.


Cardiac Mapping:

This section will cover the fundamental principles of cardiac mapping including both contact and non-contact mapping.

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Gain an understanding of the biophysics of ablation and look at radiofrequency ablation as well as cryoablation.


Tilt Table Studies:

Look into the diagnostic tool used to evaluate the presence of neuro-cardiogenic syncope.

Secrets To Success

Secrets to Success:

What do you do when confronted with the difficult case? This section will provide some tips for dealing with the toughest cases.



The whole purpose of working in the lab is to determine if an abnormal rhythm is present. This may be an arrhythmia or a dysrhythmia. This section is dedicated to learning how to identify the various rhythms that are encountered in the lab. There is discussion of the mechanisms behind the rhythms and the cardiac structures that are most commonly involved with the various rhythms.

  • Bradycardia
  • Atrial Tachycardia
  • Atrial Flutter
    • Typical
    • Atypical
  • Atrial Fibrillation
  • AVRT (WPW)
  • Ventricular Tachycardia
    • Arrhythmogenic Right Ventricular Dysplasia
    • Outflow Track Tachycardias
    • Bundle Branch Reentry
    • Ishcemic VT

The Resource Center

As I find information that may be helpful for Allied Health Professionals, I will post it in this section. This area provides information on the following subjects;

  • EP Education Resources
  • EP Organizations
  • Industry Sites
  • Tomes & Texts
  • EP Articles
  • Practice Rhythm Strips
  • Practice Intracardiac Recordings
  • Anatomy Questions

The Forum

The Forum is provided for our members to discuss subjects of interest.

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