Foreseeable variation in parameters measured at implant and follow-up of permanent pacemaker active fixation electrodes

• Published in: Medicina intensiva (English ed.) 2012-05, Vol.36 (4), p.270-276
• Main Authors: Canabal, A, Hortigüela, V, Raigal, A, Sánchez, P, Sánchez, M, Marco, C, Fernández, E, Márquez, J.A
• Format: Article
• Language: English
• Subjects: Critical Care; Internal Medicine
• ISSN: 2173-5727; 2173-5727
• DOI: 10.1016/j.medine.2012.06.006

Abstract Objectives To analyze the variations in the parameters relative to active fixation electrodes at the time of implantation and over subsequent follow-up during 6 months of the acute phase of implantation. Design A descriptive, analytical, prospective, observational cohort study was made of consecutive cases over a period of 8 months (April–December 2010). Setting Pacing unit of an Intensive Care Unit. Patients or participants Patients undergoing permanent pacemaker implantation with active fixation electrodes, implanted in both atrium and ventricle. Interventions: Measurement of variables described with a threshold analyzer during electrode fixation and at different times during the study. Main compared variables: threshold, impedance and intrinsic activity (both atrial and ventricular) before and after fixation, at 48 h, at one month and 6 months. Comparisons were made using the Student t -test for paired data, assuming significance for p < 0.05, and ANOVA to analyze the successive changes over ambulatory follow-up. Results We analyzed 40 patients, with 19 atrial and 40 ventricular electrodes, In fixation, the electrodes showed significant variation in the impedance values of the atrial lead (1188.53 ± 397.26 vs 610.69 ± 326.30 Ohms, p < 0.0001) and ventricular lead (1512.93 ± 718.07 vs 768.80 ± 224.90 Ohms, p > 0.0001). In the first 48 h it was coupled with a decrease in ventricular (0.86 ± 0.35 vs 0.48 ± 0.23 V, p = 0.0001) and atrial pacing threshold (1.10 ± 0.39 vs 0.43 ± 0.23 V, p = 0.0003), and P-wave sensing (3.61 ± 2.25 vs 2.32 ± 1.09 mV, p = 0.0463). Over follow-up, we found the parameters to be stable, with no significant changes. Conclusions After active lead fixation, a fall in impedance of the atrial and ventricular is expected. Over the next 48 h improvement in atrial and ventricular threshold may occur, in contrast to the sensitivity of the intrinsic activity, which reached significance at the P wave measured after 48 h. These values stabilize over patient follow-up and do not differ significantly in the studied acute patient course.