Optimal Lead Position Research Articles

What is the optimal lead positioning and pacing modality in cardiac resynchronisation therapy?

What is the optimal lead positioning and pacing modality in cardiac resynchronisation therapy?

What is the optimal lead positioning and pacing modality in cardiac resynchronisation therapy?

What is the optimal lead positioning and pacing modality in cardiac resynchronisation therapy?

What is the optimal lead positioning and pacing modality in cardiac resynchronisation therapy?

What is the optimal lead positioning and pacing modality in cardiac resynchronisation therapy?

Two-dimensional Numerical Simulation on Performance of Liquid Metal MHD Generator

The performance of a liquid metal MHD generator is investigated with a two-dimensional numerical simulation. The effects of the electrode length, the position of current lead connection, and the insertion of an insulator on the performance are examined taking account of the current flow in the electrode. There exists an optimal electrode length for a given distribution of applied magnetic flux density. For a short electrode, the efficiency decreases because the power output becomes small. For a long electrode, on the other hand, the efficiency also decreases owing to the leakage current from the upstream and downstream edges of the electrode. An optimal current lead position was revealed. This fact is ascribed to the distributions of induced magnetic field and the current flow in the electrode. It was found that insertion of the insulator is effective for improving the performance, by which the eddy current can be reduced. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 156(1): 25–32, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ eej.20165

P2766 What is the optimal lead position and interventricular pacing interval during cardiac resynchronisation therapy?

P2766 What is the optimal lead position and interventricular pacing interval during cardiac resynchronisation therapy?

Acute changes in pacing threshold and R- or P-wave amplitude during permanent pacemaker implantation

This study examines the changes in pacing threshold and R- or P-wave amplitude during the first 30 minutes after implantation of tined and screw-in leads. The leads examined were those of 1 manufacturer (Medtronic) and consisted of 3 ventricular pacing leads (model numbers 6957 unipolar screwin [11 patients], 6961 unipolar tined [12 patients] and 6962 bipolar tined [7 patients]) and 1 atrial lead (model number 6957J unipolar screw-in [10 patients]). After optimal lead position was obtained fluoroscopically in the right ventricular apex or right atrium, the pacing threshold and R- or P-wave amplitudes were measured at 5-minute intervals for 30 minutes. The acute ventricular pacing threshold with the screw-in lead was significantly higher than with the tined lead (0.84 ± 0.17 vs 0.58 ± 0.15 volts; p < 0.001). There was a significant (p < 0.001) acute decrease in the ventricular pacing threshold with both lead types, with the maximum decrease occurring 5 minutes after lead implantation. There was a significant acute increase in R-wave size with the ventricular screw-in lead that peaked 20 minutes after lead implantation (11.9 ± 3.0 to 14.7 ± 4.1 mV; p < 0.001). The atrial screw-in lead behaved in a manner identical to its counterpart in the ventricle. In conclusion, there are acute changes in the pacing threshold and R- or P-wave amplitude obtained with tined and screw-in pacing leads. In some patients, a pacing threshold or R- or P-wave amplitude that is initially unacceptable may improve to an acceptable level over 15 to 20 minutes without further lead manipulation, especially when an atrial screw-in lead is used.

Transverse straggling of MeV oxygen ions implanted in silicon: J J Grob et al, Nucl Instrum Meth Phys Res, B30, 1988, 34–37

This study examines the changes in pacing threshold and R- or P-wave amplitude during the first 30 minutes after implantation of tined and screw-in leads. The leads examined were those of 1 manufacturer (Medtronic) and consisted of 3 ventricular pacing leads (model numbers 6957 unipolar screwin [11 patients], 6961 unipolar tined [12 patients] and 6962 bipolar tined [7 patients]) and 1 atrial lead (model number 6957J unipolar screw-in [10 patients]). After optimal lead position was obtained fluoroscopically in the right ventricular apex or right atrium, the pacing threshold and R- or P-wave amplitudes were measured at 5-minute intervals for 30 minutes.The acute ventricular pacing threshold with the screw-in lead was significantly higher than with the tined lead (0.84 ± 0.17 vs 0.58 ± 0.15 volts; p < 0.001). There was a significant (p < 0.001) acute decrease in the ventricular pacing threshold with both lead types, with the maximum decrease occurring 5 minutes after lead implantation. There was a significant acute increase in R-wave size with the ventricular screw-in lead that peaked 20 minutes after lead implantation (11.9 ± 3.0 to 14.7 ± 4.1 mV; p < 0.001). The atrial screw-in lead behaved in a manner identical to its counterpart in the ventricle. In conclusion, there are acute changes in the pacing threshold and R- or P-wave amplitude obtained with tined and screw-in pacing leads. In some patients, a pacing threshold or R- or P-wave amplitude that is initially unacceptable may improve to an acceptable level over 15 to 20 minutes without further lead manipulation, especially when an atrial screw-in lead is used.