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
Objective: The objective of the current study was to determine the clinical factors that were associated with abandonment of a rate-control or a rhythm-control strategy in patients with atrial fibrillation(AF). Backgr...Objective: The objective of the current study was to determine the clinical factors that were associated with abandonment of a rate-control or a rhythm-control strategy in patients with atrial fibrillation(AF). Background: Although the AFFIRM Study demonstrated that outcomes are similar with a primary strategy of rate-control or rhythm-control for AF, there may be clinical or demographic factors associated with abandonment of the initial treatment strategy. Knowledge of these risk factors would be useful so that patients may be given appropriate initial therapy and, as appropriate, switched to alternative treatments earlier. Methods: Patients in the AFFIRM Study were subdivided into those who were maintained on their initial treatment strategy versus those who abandoned initial treatment strategy for alternative therapies. We determined the clinical and demographic factors associated with change in initial treatment strategy. Results: At 5 years the original treatment strategy was maintained in 85%of the patients in the rate-control arm versus 62%of those in the rhythm-control arm(P< .0001). Length of the qualifying episode of AF was associated with abandonment of both rhythm-control and rate-control strategies. Antiarrhythmic drug failure before randomization and a history of thyroid disease also were associated with abandonment of rhythm-control. Patients were more likely to maintain rate-control if they already had an implanted pacemaker or if they were older than 75 years, while an ejection fraction < 30%was associated with abandonment of the rate-control strategy. Conclusions: In patients with AF, rhythm-control strategies are abandoned significantly more often than rate-control strategies. Patients with long durations of AF on presentation or previous antiarrhythmic drug failure might be considered for rate-control as initial treatment.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Objective: The objective of the current study was to determine the clinical factors that were associated with abandonment of a rate-control or a rhythm-control strategy in patients with atrial fibrillation(AF). Background: Although the AFFIRM Study demonstrated that outcomes are similar with a primary strategy of rate-control or rhythm-control for AF, there may be clinical or demographic factors associated with abandonment of the initial treatment strategy. Knowledge of these risk factors would be useful so that patients may be given appropriate initial therapy and, as appropriate, switched to alternative treatments earlier. Methods: Patients in the AFFIRM Study were subdivided into those who were maintained on their initial treatment strategy versus those who abandoned initial treatment strategy for alternative therapies. We determined the clinical and demographic factors associated with change in initial treatment strategy. Results: At 5 years the original treatment strategy was maintained in 85%of the patients in the rate-control arm versus 62%of those in the rhythm-control arm(P< .0001). Length of the qualifying episode of AF was associated with abandonment of both rhythm-control and rate-control strategies. Antiarrhythmic drug failure before randomization and a history of thyroid disease also were associated with abandonment of rhythm-control. Patients were more likely to maintain rate-control if they already had an implanted pacemaker or if they were older than 75 years, while an ejection fraction < 30%was associated with abandonment of the rate-control strategy. Conclusions: In patients with AF, rhythm-control strategies are abandoned significantly more often than rate-control strategies. Patients with long durations of AF on presentation or previous antiarrhythmic drug failure might be considered for rate-control as initial treatment.
