A comparison of two stab-on unipolar epicardial pacing leads in children

The Oscor MP52V and Medtronic 4951 leads have similar construction and intended application. To determine if one of these designs was more suited to pediatric pacing, we reviewed implant, 3 month, and 12 months follow-up thresholds for all 18 MP52V implants at our institution from December 1989 to April 1991 and compared them to the 4951 implants from January 1982 to October 1989. Lead survival for the MP52V implants was compared to the most recent 36 4951 implants. Patients ranged in ages from 2 days-16 years (median = 4 years) and required antibradycardia pacing for congenital or acquired heart disease. Patients were compared for weight and proportion of atrial leads in each group by t-test and Fisher exact tests respectively. Energy thresholds were assessed in microJ and compared by t-test. Lead survival was defined by abandonment or replacement for any reason. Kaplan & Meier survival curves were plotted and compared by Gehan's Wilcoxan Test. There were no significant differences between the MP52V and 4951 groups for age at implant (53 months vs 80 months) or proportion of atrial implants (5/18 vs 11/36). Lead survival was poor but did not differ significantly (70% vs 78% cumulative survival at 3 years), usually failing by exit block. Implant and follow-up thresholds did not differ significantly between leads. The MP52V did not provide significant improvement in performance over the 4951. New epicardial lead designs are needed to improve lead survival and thresholds in children.