The aim of this study was to determine whether current of injury can guide adequate placement of active-fixation pacing leads. Active-fixation leads cause injury to the myocardium at the time of fixation, manifested a...The aim of this study was to determine whether current of injury can guide adequate placement of active-fixation pacing leads. Active-fixation leads cause injury to the myocardium at the time of fixation, manifested as a current of injury(COI) that may result in acute elevation of pacing thresholds. The relationship of COI to subsequent improvement in pacing thresholds is not clear. Sixty-five patients undergoing active-fixation lead implantation were enrolled. Current of injury was characterized as the duration of the intracardiac electrogram(EGM) and the magnitude of ST-segment elevation. Pacing parameters were measured up to 10 min after fixation. A total of 96 active-fixation leads were studied, and 76 leads had a current of injury. From baseline to the time of fixation, the duration of the intracardiac EGM in ventricular leads increased from 150±31 ms to 200±25 ms(p< 0.001), and the ST-segment increased from 1.5±0.2 mV to 10.0±2.0 mV(p< 0.001), with subsequent improvement in pacing thresholds from 1.5±0.4 V to 0.8±0.3 V(p< 0.001) at 10 min. Atrial leads with a current of injury had similar findings. Of the 20 leads without a COI, 5 dislodged acutely and 15 had high pacing thresholds at 10 min, requiring repositioning. The development of a COI indicates that within 10 min of fixation, pacing threshold will return to an acceptable range even if the initial measurement is high. Conversely,without a COI, lead fixation is not adequate and the lead should be repositioned.展开更多
Aretrospective analysis was performed on 52 patients with heart failure to determine the change in β-blocker therapy after cardiac resynchronization therapy(CRT). After 6 months of CRT, the number of patients receivi...Aretrospective analysis was performed on 52 patients with heart failure to determine the change in β-blocker therapy after cardiac resynchronization therapy(CRT). After 6 months of CRT, the number of patients receiving β-blocker therapy increased from 36 to 44, with improved clinical outcomes and larger β-blocker doses, indicating that these 2 therapies may work together to improve outcomes by allowing the use of larger doses of βblockers while correcting ventricular dyssynchrony.展开更多
文摘The aim of this study was to determine whether current of injury can guide adequate placement of active-fixation pacing leads. Active-fixation leads cause injury to the myocardium at the time of fixation, manifested as a current of injury(COI) that may result in acute elevation of pacing thresholds. The relationship of COI to subsequent improvement in pacing thresholds is not clear. Sixty-five patients undergoing active-fixation lead implantation were enrolled. Current of injury was characterized as the duration of the intracardiac electrogram(EGM) and the magnitude of ST-segment elevation. Pacing parameters were measured up to 10 min after fixation. A total of 96 active-fixation leads were studied, and 76 leads had a current of injury. From baseline to the time of fixation, the duration of the intracardiac EGM in ventricular leads increased from 150±31 ms to 200±25 ms(p< 0.001), and the ST-segment increased from 1.5±0.2 mV to 10.0±2.0 mV(p< 0.001), with subsequent improvement in pacing thresholds from 1.5±0.4 V to 0.8±0.3 V(p< 0.001) at 10 min. Atrial leads with a current of injury had similar findings. Of the 20 leads without a COI, 5 dislodged acutely and 15 had high pacing thresholds at 10 min, requiring repositioning. The development of a COI indicates that within 10 min of fixation, pacing threshold will return to an acceptable range even if the initial measurement is high. Conversely,without a COI, lead fixation is not adequate and the lead should be repositioned.
文摘Aretrospective analysis was performed on 52 patients with heart failure to determine the change in β-blocker therapy after cardiac resynchronization therapy(CRT). After 6 months of CRT, the number of patients receiving β-blocker therapy increased from 36 to 44, with improved clinical outcomes and larger β-blocker doses, indicating that these 2 therapies may work together to improve outcomes by allowing the use of larger doses of βblockers while correcting ventricular dyssynchrony.
