Abstract
The right atrial appendage(RAA) is the conventional site for atrial pacing. However, fixation of the RAA electrode is not always stable because of it's morphological variations. We studied the pacing stability at the superior vena cava at the junction into the right atrium (JSVC) as atrial pacing in 7 adult mongrel dogs. JSVC could be stably paced as atrial pacing using myocardial electrode(Medtronic #6400TM) fixed by sutures from inside. There were no significant differences between RAA and JSVC in the pacing and sensing threshold. Then, we used the new pacing catheter with 4 electrodes at it's spiral shaped end which was 10.5 Fr. sized in diameter. The catheter was inserted through the external jugular vein, and was easily fixed at JSVC. Though stable pacing was obtained at the beginning, sudden exit block was encountered 15 minutes later. This might be caused by the deformity of the catheter. As Polyurethane catheter was easily affected by normal temperature, a long term pacing stability could not be examined. We are to continue the study of pacing stability at JSVC after exploration the new catheter mate rial.
