High-impedance steroid-eluting lead with automatic ventricular capture verification

Abstract

There have been few reports of clinical studies on automatic ventricular capture verification with high-impedance steroid-eluting leads. Six patients were implanted with Medtronic 5554-45 leads in the atrium and Medtronic 5054-45 leads in the ventricle. A significant difference was observed (P = 0.0032) between the mean atrial evoked response (ER) (3.99 ± 1.53 mV) and the mean ventricular ER (15.21 ± 6.97 mV), although no significant difference was observed (P = 0.4637) between the mean lead polarization signals (PS) in the atrium (1.86 ± 1.53 mV) and in the ventricle (1.37 ± 0.33 mV). In all patients, the effect of autocapture was satisfactory in the ventricle; however, this function did not work properly in the atrium in four of six patients, indicating that the use of autocapture function in the atrium is not recommended. In a separate case, clinical application of the autocapture function was performed for a 73-year-old woman with bradycardia and atrial fibrillation. A Medtronic 5054-52 ventricular lead and a St. Jude Medical 5130L pulse generator were implanted. At implantation the ER was 19.15 mV, the PS was 1.96 mV, and the unipolar pacing threshold was 0.375 V (at 0.4 ms pulse width). These data seemed acceptable for proper autocapture function. At 6 months postoperatively, the ER was 16.25 mV, the PS was 1.96 mV, and the unipolar pacing threshold was 0.5 V (at 0.4 ms pulse width). The autocapture function worked properly.