RESUMEN
BACKGROUND: Lead-associated complications and technical issues in patients with cardiac implantable electronic devices are common but underreported in the literature. METHODS: All patients undergoing implantation of the Osypka QT-5® ventricular lead at the University Clinic St. Pölten between 1 January 2006 and 31 December 2012 were retrospectively analyzed (n = 211). Clinical data including pacemaker follow-up examinations and the need for lead revisions were assessed. Kaplan-Meier analysis to estimate the rate of lead dysfunction during long-term follow-up was conducted. RESULTS: Patients were followed for a median of 5.2 years (interquartile range (IQR) 2.0-8.7). R-wave sensing properties at implantation, compared to last follow-up, remained basically unchanged: 9.9 mV (IQR 6.8-13.4) and 9.6 mV (IQR 5.6-12.0), respectively). Ventricular pacing threshold significantly increased between implantation (0.5 V at 0.4 ms; IQR 0.5-0.8) and the first follow-up visit (1.0 V at 0.4 ms; IQR 0.8-1.3; p < 0.001) and this increase persisted throughout to the last check-up (0.9 V at 0.4 ms; IQR 0.8-1.2). Impedance significantly declined from 1142 Ω (IQR 955-1285) at implantation to 814 Ω (IQR 701-949; p < 0.001) at the first check-up, followed by a further decrease to 450 Ω (IQR 289-652; p < 0.001) at the last check-up. Overall, the Osypka QT-5® ventricular lead was replaced in 36 patients (17.1%). CONCLUSIONS: This report shows an unexpected high rate of technical issues of the Osypka QT-5® ventricular lead during long-term follow-up.
RESUMEN
BACKGROUND: No published data exist about the safety of diagnostic magnetic resonance (MR) of the heart performed in a larger series of patients implanted with MR conditional pacemakers (PM). The purpose of our study is to analyse safety and potential alterations of electrical lead parameters in patients implanted with the EnRhythm/Advisa MRI SureScan PM with 5086MRI leads (Medtronic Inc.) during and after MR of the heart at 1.5 Tesla. METHODS: Patients enrolled in this single center pilot study who underwent non-clinically indicated diagnostic MR of the heart were included in this analysis. Heart MR was performed for analyses of potential changes in right and left ventricular functional parameters under right ventricular pacing at 80 and 110 bpm. Atrial/ventricular sensing, atrial/ventricular pacing capture threshold [PCT], and pacing impedances were assessed immediately before, during, and immediately after MR, as well at 3 and 15 months post MR. RESULTS: Thirty-six patients (mean age 69 ± 13 years; high degree AV block 18 [50%]) underwent MR of the heart. No MR related adverse events occurred during MR or thereafter. Ventricular sensing differed significantly between the FU immediately after MR (10.3 ± 5.3 mV) and the baseline FU (9.8 ± 5.3 mV; p < 0.05). Despite PCT [V/0.4ms] was not significantly different between the FUs (baseline: 0.84 ± 0.27; in-between MR scans: 0.82 ± 0.27; immediately after MR: 0.84 ± 0.24; 3-month: 0.85 ± 0.23; 15-month: 0.90 ± 0.67; p = ns), 7 patients (19%) showed PCT increases by 100% (max. PCT measured: 1.0 V) at the 3-month FU compared to baseline. RV pacing impedance [Ω/5V] differed significantly at the FU in-between MR scans (516 ± 47), and at the 15-month FU (482 ± 58) compared to baseline (508 ± 75). CONCLUSION: The results of our study suggest MR of the heart to be safe in patients with the MR conditional EnRhythm/Advisa system, albeit although noticeable but clinically irrelevant ventricular PCT changes were observed.