Index
Ep Defined | Getting Started | Working in the EP Lab
Right Atrium | Right Ventricle | Left Atrium | Left Ventricule | Cardiac Conduction | Cardiac Cell Properties | Action Potential | Sympathetic or Not | Med Page
Electrograms Defined | Recording Modes | Electrode Spacing | Filters | EGM Interpretation | Arrhythmia Analysis
The Physical Lab | Tools of the Trade
Setting Up | Catheter Placement | Baseline Measurement | SNRT | Conduction Study | Arrhythmia Induction | Pacing Protocols | Ablation | Tilt Table | Secrets to Success
Bradycardia | Atrial Tach | Atrial Flutter | Atrial Fibrillation | AVNRT | AVRT | Ventricular Tachycardia
Surface ECG's | Intracardiac Questions | Med Challenge | Advanced

Introduction to EP - EP Defined

What, exactly, is cardiac electrophysiology?

 

          EP is the study of the cardiac conduction system. The purpose is to identify and correct abnormal rhythms of the heart. To achieve this, it is important that we understand the normal rhythm of the heart. By comparing what we know to be normal with how what we are seeing is different from that, we can gain derive a great deal of information on the type of abnormal rhythm that is occurring.

          In order to understand what electrophysiology is and what it takes to work in an EP lab, there are a number of areas that we first must understand. This web site is set up as an instructional tool that will allow the reader to step through each area of key information. The goal of this process is to gain a solid understanding of working in this field. To achieve this, the following sections have been written;

The EP Lab – This section discusses the environment of the lab and the tools used during EP procedures. When we first come to work in the lab, by necessity, we learn to operate the equipment.

Anatomy & Physiology – Learning to use the tools of EP requires a basic knowledge of the heart. In the early stages, we begin to learn a bit about the structures of the heart and how they function. Without this information, we can not take the next step into understanding the basics of how EP is performed.

Fundamentals of EP – This section discusses how the electrical signals of the heart are recorded and displayed. It also takes the user into the anatomy and physiology of the causes behind the various different arrhythmia types and the steps used to distinguish what type of rhythm is being observed.

EP Procedures – This section looks at the procedural aspects of putting the previously gained knowledge into practice. Information in this section deals with the different techniques used to evaluate how the electrical conduction system is functioning. These techniques also allow us to determine the specific abnormal rhythm or rhythms encountered.

Cardiac Arrhythmias – Now that we know how to record, evaluate and identify the different abnormal rhythms we take a direct look at the rhythms themselves. This includes discussion of the mechanism of each arrhythmia along with recordings of each one.

          The first step in the learning process is to define cardiac electrophysiology as a procedure. Above it was stated that EP is the study of the cardiac conduction system. The process of analyzing the electrical signals of the heart falls into the category of diagnostic electrophysiology. In order to diagnose a rhythm, we first must record it.

          A recording of an electrical signal is known as an electrogram. When the electrical signal is specific to the heart, we refer to it as a cardiac electrogram or an electrocardiogram. The term electrocardiogram is the origin of the anagram ECG. When you see the term ECG, it refers to the electrocardiogram. As this term was originally described in a Germanic language, it was originally written as EKG.

          There are two types of electrograms used in EP. The first is recorded using electrodes attached to the patient’s skin. These electrodes allow us to visualize the surface ECG, also known as the 12 lead electrocardiogram. When the electrical signals are recorded from inside the heart, they are referred to as intracardiac electrograms. The anagram EGM is often used to refer to these signals.

          The ability to record cardiac electrograms is the very basis of the field of cardiac electrophysiology. If the EP initiate starts out with the understanding that everything that is performed in the lab is done based upon the ability to record and interpret these signals, then that person has taken the most important step in learning EP. Everything you do in the lab is based upon recording and interpreting these signals. It is this knowledge that allows the EP practitioner to successfully complete an EP procedure.

          Once the signals have been recorded and the abnormal rhythm identified, the determination is made as to what the best therapeutic approach is. There are a number of choices that can be made in dealing with an abnormal rhythm. The specific choice will be determined by the nature of the rhythm identified and what is best for the patient.

          Many arrhythmias are corrected using a process known as ablation. The ablation procedure allows the physician to eliminate the cells that are causing the abnormal rhythm. The physician may also choose to utilize medications to help control the arrhythmia. Some cardiac conditions may require the implantation of a pacemaker or an internal cardiac defibrillator (ICD). Pacemakers help prevent that patient’s heart rate from dropping too low. The ICD is used to deliver an electric shock that “resets” the patient’s heart rhythm. ICD’s are used to control rhythms that may go dangerously fast.   It is also possible that the rhythm identified may require no action at all. While advances in therapy have made it possible to treat almost all abnormal rhythms, sometimes therapy is not needed, or is too risky for the patient.

          This brief description of EP will be expanded upon throughout the various sections of this web site. There is a lot of information to be learned. Relax and do not try to rush through it all. It will take around 2 years to become really proficient in the EP lab. Even at that point, there will still be much to learn. One of the great things about cardiac electrophysiology is that it is a field of medicine that can challenge you for years to come.

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