AN ESOPHAGEAL AND GASTRIC APPROACH TO VENTRICULAR PACING

Using a unipolar esothoracic pacing system (where current passes from a point source positioned in the distal esophagus to a chest wall pad) and pulse duration of 50 msec, satisfactory 1:1 ventricular capture w as obtained in 57 (86%) of 66 patients, with a mean threshold current of 27.7 mA at an optimal depth of 40.3 cm from the lower lip. When the unipolar esothoracic and bipolar transesophageal ventricular pacing s ystems were compared, the bipolar system was associated with a lower s uccess rate and higher threshold current. When unipolar esothoracic pa cing and gastrothoracic pacing (where current passes from a point sour ce positioned in the stomach to a chest wall pad) were compared in 23 patients with bradyarrhythmia, ventricular capture was achieved using gastrothoracic pacing in 22 patients (96%) and esothoracic pacing in 2 1 (91%): gastrothoracic pacing required less current (16.0 mA +/- SD 7 .2 vs 25.8 mA +/- SD 8.6). Optimal ventricular capture occurred using a unipolar gastrothoracic pacing electrode inserted to an average dept h of 44.3 cm together with a high impedance chest pad (250 Omega) plac ed in the fourth interspace at the left sternal edge, with 50-msec cur rent pulses and a mean threshold of 16.0 mA. Thus, using a gastroesoph ageal electrode system, ventricular pacing can be achieved successfull y, and the availability of such a system could play a major role in re suscitation of patients from severe bradyarrhythmias.