Long-term follow-up of pulse width threshold of transvenous and myo-epicardial leads.
Postoperative pulse width thresholds were measured at a constant of 5 volts in 140 patients. In 41 patients, transvenous atrial and/or ventricular leads were implanted at a median age of 13 years (3-78 yrs). Myo-epicardial leads were implanted in 99 patients at a median age of 8 3/4 years (1 wk to 76 yrs). The initial rapid rise of threshold was found to persist not longer than to the third follow-up period of 11 days to 5 weeks in all atrial and transvenous ventricular leads; in myo-epicardial ventricular leads it persisted until the period of more than 5 weeks to 6 months. During initial rise, pulse width threshold m + sem did not exceed 0.45 ms. We therefore suggest that a pulse width setting of 0.5 ms at 5 V is a safe setting for this period. In only one patient did a late rise of threshold occur. The comparison of pulse width thresholds of transvenous versus myo-epicardial leads showed lower mean values for transvenous atrial leads in each follow-up period, but the difference was not statistically significant. The pulse width thresholds of transvenous ventricular leads were significantly lower than those of myo-epicardial leads in some follow-up periods. We therefore conclude that transvenous leads have a slight advantage with regard to postoperative pulse width threshold.
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D004567:Electrodes, Implanted; D004699:Endocardium; D005500:Follow-Up Studies; D006325:Heart Atria; D006352:Heart Ventricles; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008875:Middle Aged; D010138:Pacemaker, Artificial; D013997:Time Factors