The Long-term Follow-up Study Of Active-fixation Leads

Objective: With a broadening of the indications for pacing and an aging population, the number of pacemaker implantation is increasing. The development of pacemaker has experienced more than 50 years. At the same time, pacing electrodes have also taken place with every passing day. Traditional, passive-fixation lead offers easily placement, simply operation and lower price and so on, so it has been most commonly used. Now, people have deep understanding of special position of heart (right ventricular outflow tract, superior atrial septum, inferior atrial septum). Because of the advantages and features of active-fixation lead, it will be used more and more widely in china. The purpose of the study was to observe the long- term parameters of active-fixation lead and to explore the advantage of its application.Methods: 124 patients (67 men, mean ages 66.20±11.31 years,) were implanted by the permanent pacemakers and the active-fixation leads (atrial active-fixation lead 1, ventricular active-fixation leads 124) from Jan. 2006 to Aug. 2007. Lead Models: TendrilTM1688T were 94 (St.Jude Medical), Capsurefix 5076 were 31 (Medtronic). Implantation sites: 1 was implanted in the right atrial appendage, 93 in ventricular septum, 31 in ventricular apex. The parameters were followed up during the operations and postoperative 1-month, 3-month, 6-month and 12-month.Results:①There were no complications during the operations.②Pacing parameters: The pacing thresholds were higher (0.60±0.16V) in operations and decreased the postoperative 1 month (0.51±0.20V). There was significant statistical difference between the operations and the postoperative 1 month (P<0.01). There were not significant differences during postoperative 1 month (0.51±0.20V), 3 month (0.54±0.21V), 6 month (0.56±0.20V) and 12 month (0.55±0.20V), P>0.05. There were not significant differences in the sensitivities (P>0.05) during the operations (11.60±3.71mV) and postoperative follow-up (11.40~11.85mV). Impe- dances were higher in the operations (711.86±114.40?) and decreased in postoperative follow-up (393.72~401.09?). There were significant stati- stical differences in the operations and postoperative follow-up (P<0.01). The pacing thresholds increased in 2 patients (1.6% leads in St.Jude Medical) after 6 month of operation. One patient with sick sinus syndrome was implanted by DDDR pacemaker, and the ventricular active-fixation lead was placed apex. The pacing threshold was 0.9V in operation and increased at 3 month follow-up (1.25V) and 6~12month follow-up (6.0V). The lead was not replaced for prolonging the AV interval to 250ms and no dependent ventricular pacing in the patient without atrial ventricular block (AVB). Another patient with III degree AVB was implanted by DDDR permanent pacemaker and the active-fixation lead in the high ventricular septum and replaced for the pacing threshold increased to 5V in 6 month follow-up.Conclusion: The dislocation rate of active-fixation leads was lower and the stability of active-fixation leads was more firm than passive- fixation leads. The thresholds and impedances were higher during the operation for local edema. But the threshold and impedance may be dropped with the time goes on. The incidence of threshold rising was low (1.6%), and the pacing parameters were stability in postoperative follow up.