© 2005 The European Society of Cardiology. Published by Elsevier Ltd. All rights reserved.
CP10: OUTCOME OF RIGHT VENTRCULAR BIFOCAL PACING LEADS: APEX VERSUS OUTFLOW TRACT
1Zaansch MC Zaandam; 2Waterland Hospital Purmerend, Netherlands
BACKGROUND: In 47 pts (40 BRIGHT pts in 9 participating centres) with bifocal pacing in CHF 2 leads are used for RV pacing: apex (Ap) and outflow tract (OT).Pts characteristics: age 69 ± 9 years, 11 female/36 male, NYHA class 3,0 ± 0,3; EF 24 ± 6%; QRS-width178 ± 19 ms.
METHODS: Positioning attempts and complications were noted. Pacing & sensing measurements were done with the Era 300B* at implant or via the pacemaker (STRATOS-LV*): pacing threshold (Thr), R-wave amplitudes (wa) and pacing impedances (Imp), up to 10 months follow up.
RESULTS: For positioning of the Ap and OT lead 1,7 ± 0,8 (1-4) vs. 2,4 ± 2,2(1-10, p<0.05) attempts were needed, with respectively passive fixation vs. active fixation (ELOX*, *=Biotronik). In 2 pts advanced AV block occur—red acutely during active fixation at the RVOT. Conduction recovered < 4 months. Positioning of the Ap lead caused ventricular fibrillation in one pt. Two leads were repositioned due to extreme high Thr's (OT1/Ap1) and two OT leads showed early dislocation and were repositioned successfully. Ap-wa is significant higher vs OT-wa: 22±12 vs.14±9 mV (p<0,001). During follow Ap-wa remained stable (average 19 mV) and OT-wa could not be measured. Thr at Ap was lower 0,5±0,3 Volt vs. OT: 0,7± 0,3 (p<0,0002), which difference remained during follow up, but both showed a significant increase at 1 month: Ap increased to 1,2 ± 0,7 Volt and OT to 1,8 ± 1,1 (both p < 0,0001), and both declined at month 7 to Ap 0,9 ± 0,3 (n= 16, p=0,085) and OT 1,3 ± 0,4 (n=16, p=0,089). Imp was lower at the OT, vs. at the Ap: 627±187 Ohm vs. 981±240 Ohm (p < 0,00001).
CONCLUSION: Significant differences were observed between leads positioned in the OT vs Ap; this partly due to the design of the leads and partly due to the location in the right ventricle. Complications are acceptable, but could be reduced by the growing experience of the investigators.