[Intragastric and intraesophageal electrocardiography in normal subjects]

This paper studies the different electrocardiographic morphologies related to unipolar, intragastric and intra-esophagic leads among 62 normal subjects, 48 male and 14 female with varying ages from 14 to 49. Each one of the volunteers was introduced with a thin nasogastric sounding lead having at its distal extremity a small electrode positioned, under radioscopic management, into the subdiaphragmatic section. The exploring electrode kept being withdrawn centimeter after centimeter with simultaneous recording of the lead II. This procedure has been repeated up to the tracheal bifurcation. The tracings have been analysed in six levels: ventricular, atrioventricular transition, low atrial, mean atrial, high atrial and supra atrial. At ventricular level the P wave has been similar to the one obtained in D2; the QRS complex presented similarities to normal aVF even though with significant exceptions; the T wave was positive and asymmetric. At atrioventricular transition level, the P wave was peaky or diphasic. The QRS complex presented deep Q and missing s or S wave which had been obtained at ventricular level. At atrial level (low, mean and high) the P wave presented a small initial negative deflection in 35%, 78% and 92% among the tracings corresponding to the depolarization of the right atrium followed by a diphasic deflection (plus-minus) that would coincide with the depolarization of the left atrium. The QRS complex, on the other hand, has been diphasic (minus-plus) or with QS morphology. At supra atrial level it paralleled in all cases to normal of a VR lead.