Clinical evaluation of a new esophageal electrode, with particular reference to the bipolar esophageel electrocardiogram part II. Observations in cardiac arrhythmias

Abstract

1. 1. The application of the salt-bridge method of esophageal electrocardiographic registration to the development of a simple and clinically reliable bipolar esophageal lead has been outlined. The results of multichannel, multilevel esophageal lead surveys made with this device upon 26 subjects with normal sinus mechanism and 74 with various cardiac arrhythmias are reported here. The leads which were routinely recorded simultaneously in these surveys include unipolar registration from the proximal and distal members of the lead assembly (VE P and VE D), the difference in potential between these two members (Lead BE), and a conventional extremity lead (usually Lead II). 2. 2. A careful and extensive analysis of the group of subjects with normal sinus rhythm confirms that both the unipolar and bipolar esophageal leads greatly exceed the capability of conventional body surface leads in depicting the forces of atrial depolarization and repolarization. In this group the bipolar esophageal leads appeared to have certain advantages as compared to the unipolar leads, and in no instance did they prove inferior to the unipolar leads. 3. 3. In our evaluation of the group of subjects with cardiac arrhythmias the esophageal leads offered unsurpassable diagnostic superiority as compared to the conventional leads. In a number of cases the bipolar esophageal lead was decidedly better than the unipolar leads, although this was not invariably so. 4. 4. Our clinical observations of the unipolar and bipolar esophageal electrocardiograms appear to confirm the theoretical principles which were previously developed in this laboratory. As anticipated, the bipolar lead has proved to be particularly sensitive to alterations in the time course of atrial depolarization. It also provides a ready means for sorting atrial from ventricular deflections, especially in situations in which they occur concomitantly. 5. 5. On the basis of the experiences reported here, we believe that no complicated or perplexing arrhythmia will have been studied adequately without the benefit of esophageal tracings. The relative technical simplicity of the salt-bridge principle as applied to unipolar and bipolar esophageal registration greatly minimizes the demands which such a procedure would ordinarily impose upon the physician's time and energy.