• John Rickard, Milos Taborsky, David Bello, W B Johnson, Brian Ramza, Yanping Chang, and Bruce L Wilkoff.
• Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland. Electronic address: jrickar5@jhmi.edu.
• Heart Rhythm. 2014 Feb 1; 11 (2): 222-9.

BackgroundOwing to potential patient harm, magnetic resonance imaging (MRI) in patients with cardiac implantable electronic devices has traditionally been contraindicated. Following the EnRhythm MRI SureScan Study, an MR conditional pacemaker with modified leads was approved by the Food and Drug Administration. Electrical and handling characteristics of MR conditional pacing leads compared with those of traditional leads have not been established.ObjectiveTo compare short- and long-term performance of the Medtronic 5086MRI lead with that of the Medtronic 5076 lead.MethodsPatients (n = 466) implanted with 2 5086MRI leads (EnRhythm MRI Study) and 316 patients implanted with 2 5076 leads in 2 prospective clinical investigations were analyzed.ResultsElectrical characteristics were stable in both groups at implant and at 12 months and were clinically acceptable throughout. Ventricular capture thresholds were slightly higher at 12 months for the 5086MRI lead than for the 5076 lead (0.93 ± 0.47 V vs 0.74 ± 0.42 V; P < .001). Ventricular sensing amplitudes for the 5086MRI lead were lower at implant (9.0 ± 4.7 mV vs 13.9 ± 6.9 mV; P < .001) and 12 months (9.8 ± 4.8 mV vs 15.4 ± 7.5 mV; P < .001) than for the 5076 lead. There was no statistical difference in lead handling. At 12 months, the estimated right atrial lead-related complication-free survival rate was 99.3% for the 5086MRI lead and 99.6% for the 5076 lead (log-rank P = .65), and the estimated right ventricular lead-related complication-free survival rates were 98.5% and 100% (log-rank P = .03). Acute lead dislodgments occurred in 12 patients with the 5086MRI leads (2.6%) compared with 2 patients with 5076 leads (0.6%) (p = .05) than in 0.6% of the patients with the 5076 lead (P = .05).ConclusionsThe 5086MRI lead demonstrates clinically acceptable electrical characteristics while providing safe access to MR-guided diagnostics. However, compared with the 5076 lead, the 5086MRI lead exhibits lower ventricular sensing, slightly higher ventricular capture thresholds, and higher acute lead dislodgement rate.© 2014 Heart Rhythm Society Published by Heart Rhythm Society All rights reserved.

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