SPECIAL PACEMAKER CATHETER TECHNIQUES - TRANS-MEDIASTINAL PLACEMENT OF SENSING ELECTRODES

Abstract

The clinical utilization of atrial programmed pacemakers is limited by the lead systems available for sensing of atrial activity. The endocardial method of lead placement is burdened by a dislodgement rate of up to 30%. Alternatively, the patient must submit to the risks of a thoracotomy. Patients (31) were treated with a transmediastinally, retrocardially positioned atrial detector electrode. In 20 patients (65%) the detector performed as desired with no postimplant revision. In 11 patients (35%) corrective measures were required primarily to correct lead placement; 7 of these were corrected under local anesthesia merely by pulling the catheter. Spontaneous lead dislocation occurred in 4 patients. Four patients (13%) underwent remediastinoscopy due to cranial displacement of the detector electrode with a resulting decrease in atrial potential to less than 0.5 mV. For technical reasons, the lead placements were performed without the benefit of X-ray illumination, with only an ECG check of the posterior atrial wall, and this may account for the relatively high incidence of revision. Transmediastinal placement of sensing electrodes presents a practicable alternative to methods presently used.