Elsevier

Journal of Electrocardiology

Volume 40, Issue 5, September–October 2007, Pages 457.e1-457.e7
Journal of Electrocardiology

Education
3D Heart: A new visual training method for Electrocardiographic Analysis

https://doi.org/10.1016/j.jelectrocard.2007.04.001Get rights and content

Abstract

This new training method is based on developing a sound understanding of the sequence in which electrical excitation spreads through both the normal and the infarcted myocardium. The student is made aware of the cardiac electrical performance through a series of 3-dimensional pictures during the excitation process.

The electrocardiogram 3D Heart 3-dimensional program contains a variety of different activation simulations. Currently, this program enables the user to view the activation simulation for all of the following pathology examples:

Simulations relating to other cardiac abnormalities, such as bundle branch block and left ventricular hypertrophy fasicular block, are being developed as part of a National Institute of Health (NIH) Phase 1 Small Business Innovation Research (SBIR) program.

Introduction

Cardiologists are becoming increasingly challenged to use the standard 12-lead electrocardiogram (ECG) for diagnosis of the location and relative size of myocardial infarcts. A new method of visual training is proposed to make these diagnoses more obvious and accurate. This new method is based on developing a sound understanding of the sequence in which electrical excitation spreads through both normal and the infarcted myocardium.1, 2, 3, 4 The student is made aware of cardiac electrical performance through a time series of 3-dimensional (3D) pictures during the excitation process. This series of pictures illustrates the heart activation status, the resultant vector sum, its loop, and its relation to 12-lead ECG signals.5, 6

The availability of reperfusion therapy via primary coronary intervention (PCI) challenges clinicians to use the standard 12-lead ECG for diagnosis of acute myocardial infarction, to select patients for this intervention, and to assess the therapeutic effect. Different electrophysiologic processes are responsible for the ECG abnormalities that signify the acute transmural ischemia and the chronic myocardial infraction. The acute ST-segment deviation toward the involved region is caused by the “injury”-induced alteration of the membrane potentials during repolarization; and the chronic QRS deviation away from the involved region is caused by the infarction-induced subtraction from the balance of multidirectional depolarization “vectors.”

These altered ECG waveforms can be recognized by the responsible clinician either by memorization of patterns or by understanding how the cardiac electrophysiological process is manifested on the body surface recordings. Previous studies have documented the superior clinical diagnostic performances achieved when such understanding has been provided.7, 8, 9

A PC-based training program 3D Heart, has been developed to test the utility of this method. The illustrations in this article are from the 3D Heart program. When running the training program, the student can rotate, translate, and resize the heart and loop 3D images that are illustrated in this article.

As an example of this process, Fig. 1 presents a snapshot at 20 milliseconds after the start of the QRS complex in both a normal heart and a heart with a medium-sized anterior MI. This snapshot is taken from a movie of 35 frames that shows the cardiac excitation process in terms of the active surface shown in bright red and the vectors (indicated by arrows) that emerge from the activation of the 12 divisions: superior, middle, and apical sectors of each of the 4 quadrants: (1) anteroseptal, (2) anterosuperior, (3) posterolateral, (4) inferior.

Section snippets

Heart to loop

The cardiac electrical signal recorded on the body surface represents the summation vector of the individual vectors emerging from all of the segments at a particular point in time. Early work in this area used the Huygens principal to generate a dipole wave front that propagated from the endocardial surface to the epicardium with each new front created by a projection perpendicular to its present location.2 An electrical dipole of unit strength is assigned to each small surface segment. The

New visual aids for conduction defects

A phase 1 SBIR effort is in progress for the National Institute of Health to expand the present 3D heart instructional program to include many more disease states:

  • 1.

    Left bundle branch block (LBBB).

  • 2.

    Right bundle branch block (RBBB).

  • 3.

    Left anterior fascicular block (LAFB).

  • 4.

    Left inferoposterior fascicular block (LIFB).

These additional instructional simulation aids should make the program a more complete guide to the understanding of many types of heart problems.

In the normal heart, the left ventricle is

References (11)

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This work is being supported by the National Institute of Health under Grant 1 R43 HL077032-01A2.

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