Simultaneous esophageal and standard electrocardiographic leads for the study of cardiac arrhythmias

Abstract

The value of esophageal leads for the study of cardiac arrhythmias is well established, but we found difficulties in some cases; (1) It may be impossible to distinguish P and QRS or to separate them when they are superimposed, because their component rapid deflections may be similar, and their relative sizes may vary widely, P being equal to, larger, or smaller than QRS; and (2) Differences in configuration of QRS and even P may be more apparent in other leads. These difficulties may be obviated by the use of a simultaneous standard lead. The complementary value of simultaneous standard and esophageal leads is illustrated in six cases: (1) atrial tachycardia (flutter) with multifocal ventricular ectopic systoles or variations in ventricular conduction; (2) A-V dissociation with interference, different atrial foci discernible only in the E lead, and different QRS complexes discernible only in Lead III; (3) atrial tachycardia (flutter) with alternating bidirectional P waves; (4) atrial parasystole, difference in atrial foci apparent in the standard leads, but not in the E lead; (5) ventricular tachycardia with retrograde conduction to the atria; and (6) double reciprocal beats (return extrasystoles) after ventricular ectopic systoles. The arrhythmia of Case 3 has not previously been described and that of Case 6 only once. Their recognition is an indication of the value of the method.