Variación esperable de parámetros medidos en el implante y seguimiento de electrodos de fijación activa de marcapasos definitivos

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 48hours, 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 (1,188,53±397,26 vs 610,69±326,30 ohms, p<0,0001) and ventricular lead (1,512,93±718,07 vs 768,80±224,90 ohms, p>0,0001), in the first 48hours it was coupled with a decrease in ventricular (0,86±0,35 vs 0,48±0,23 volts, p=0,0001) and atrial pacing threshold (1,10±0,39 vs 0,43±0,23 volts, p=0,0003), and p-wave sensing (3,61±2,25 vs 2,32±1,09mv, 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 antrial and ventricular is expected, over the next 48hours 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 48hours, these values stabilize over patient