Computer Modeling in EP Education

Day 1

Remember the first day you stumbled into the EP lab? You were likely eager to work in procedural medicine and fascinated with the technology, but also possibly overwhelmed by the electrograms, x-ray, ultrasound and 3D mapping. 

VisibleEP is interactive learning software that was created to help students avoid ‘being overwhelmed’ by bringing a virtual EP laboratory to your personal computer. One can study and practice EP on their terms, away from the frantic pace of the clinical laboratory.

The core of the interactive software is a computational model of electrical propagation that was conceived by Dr. Peter Spector and colleagues at the University of Vermont,¹ and originally designed to study the relationship of tissue excitation and electrogram recordings.² It soon became apparent that the power of real-time simulation could be harnessed to provide students in EP with an interactive training tool that allows for the practice of EP studies away from the time pressure of the clinical lab.

Virtual EP Lab

Becoming acquainted with electrophysiology can be a daunting task. Mastering the language of electrograms alone usually requires a prolonged learning process: before you can interpret beat-to-beat activation on a live screen, you first have to understand the individual deflections and assemble multiple electrograms into a coherent pattern to form a picture of the rhythm in your mind’s eye. VisibleEP enables the user to observe the spread of electrical activity through the heart and establish the critical link between cardiac excitation and the resultant electrograms. (Figure 1)

One can rotate the heart through 3D space, or open it up and peer inside. Users can watch propagation (and electrograms) at any speed, as well as pause activation or play it backwards.

Electrical propagation and the ensuing electrograms are simulated in real time; as you alter the position of a catheter, electrogram morphology will change accordingly. In addition, the user has free reign over catheter design, so they can create new catheters with any numbers of electrodes, varying inter-electrode spacing and recording configuration (unipolar or bipolar). (Figure 2) 

One can also induce various rhythms such as atrial fibrillation or ventricular tachycardia. The user can alter the electrophysiologic properties of individual cells or groups of cells (e.g. the slow pathway) to create the substrate for AVNRT, atrial flutter or AV reciprocating tachycardia. Using an integrated full function stimulator, one can study the heart’s electrical properties and induce arrhythmias. The user can diagnose arrhythmias with differential pacing or by creating a 3D electroanatomic map. (Figure 3) It is also possible to deliver ablation and see if you made the correct diagnosis. VisibleEP is a complete virtual EP lab on the laptop computer. (See sample video on www.eplabdigest.com.)

Real-time Interactive Education

This virtual EP laboratory is wrapped inside interactive didactic books to give trainees a guided learning experience. (Figure 4) The study material is designed on the premise that teaching the fundamental concepts of electrophysiology enables a student to apply those principles to whatever clinical scenarios they encounter. For example, you first learn about how source-sink relationships can lead to unidirectional block, which is a requirement for reentry. In a simplified circuit one can then try to induce reentry, and once initiated, terminate it via anti-tachycardia pacing. This interactive environment allows students to both learn by trial and error and visualize the wavefronts to understand the critical components involved in initiation and termination of reentry. The same concepts will be applied in more advanced chapters, such as “Differential Diagnosis of Narrow Complex Tachycardia”; here, students are presented with clinical cases and asked to interpret ECGs and intracardiac electrograms, and perform pacing maneuvers to identify the rhythm. 

The didactic material spans from basic concepts (“Ion Channels and Action Potentials”, “Principles of Propagation”, “Arrhythmia Mechanisms”) to hands-on EP (“Mapping of Accessory Pathways”, “3D Mapping and Entrainment”). Along with the didactic material, each chapter includes quizzes, exercises and clinical cases.

VisibleEP’s simulation software can also be integrated with clinical mapping and electrogram recording systems as well as the Simbionix physical catheter simulator (Figure 5). This allows students to learn electrophysiology in a hands-on interactive environment. This offers a great advantage to the doctors, nurses and technicians using computer simulation in EP education — it enables them to see the rhythm and interact with it in real time.

Disclosures:  Outside the submitted work, Dr. Habel reports consulting fees/honoraria from Medtronic. In addition, Dr. Habel holds equity in Visible Electrophysiology, LLC.

References

1. Spector PS, Habel N, Sobel BE, Bates JHT. Emergence of complex behavior: an interactive model of cardiac excitation provides a powerful tool for understanding electric propagation. Circ Arrhythm Electrophysiol. 2011;4(4):586-591.
2. Correa de Sa DD, Thompson N, Stinnett-Donnelly J, et al. Electrogram fractionation: The relationship between spatiotemporal variation in tissue excitation and electrode spatial resolution. Circ Arrhythm Electrophysiol. 2011;4(6):909-916.