Institut Universitaire de Cardiologie et Pneumologie de Québec, 2725 Chemin Sainte-Foy Québec, QC, Canada.
Europace. 2011 Mar;13(3):409-15. doi: 10.1093/europace/euq499. Epub 2011 Jan 26.
Cardiac resynchronization therapy (CRT) improves survival and reduces heart failure symptoms. However, phrenic nerve stimulation and high pacing thresholds are common problems that limit CRT effectiveness. Current technology allows reprogramming of left ventricular (LV) pacing vectors, permitting 'electronic repositioning' to overcome both phrenic nerve stimulation and high pacing output without the need for re-operation.
Patients underwent prospective evaluation of a CRT system implantation with a bipolar LV. Optimal LV threshold and avoidance of phrenic nerve stimulation were determined at baseline and at 6 months. A subset of 48 patients underwent more detailed evaluation of pacing threshold and phrenic nerve stimulation at baseline and at 6 months. Between 2004 and 2007, 228 patients underwent CRT implantation (64 CRT pacemakers, 164 CRT defibrillators). At baseline, electronic reprogramming to determine an alternate configuration compared with standard LVtip to LVring found a ≥ 1.0 V reduction in pacing threshold in 80 patients (35%). Of the 17 patients who had an LVtip to LVring configuration and high pacing threshold (>5.0 V), 16 could be reduced by >1.0 V (94%) and 11 could be reduced by >2.0 V through electronic repositioning alone without repositioning the lead (65%). At implant, there were 48 patients with phrenic nerve stimulation at less than maximum pacing output (21%) using the standard LVtip to LVring configuration. In 37 cases (77%), there was at least one other configuration with no phrenic nerve stimulation, which prevented the need for lead revision.
Electronic repositioning is an important tool in the management of CRT patients which may help to lower thresholds, avoid phrenic nerve stimulation, and prevent unnecessary re-operations for LV lead repositioning.
心脏再同步治疗（CRT）可改善生存率并减轻心力衰竭症状。然而，膈神经刺激和高起搏阈值是常见问题，限制了 CRT 的疗效。目前的技术允许重新编程左心室（LV）起搏向量，实现“电子重新定位”，在无需再次手术的情况下克服膈神经刺激和高起搏输出。
患者前瞻性评估了具有双极 LV 的 CRT 系统植入术。在基线和 6 个月时确定 LV 阈值最佳且避免膈神经刺激。48 例患者的起搏阈值和膈神经刺激在基线和 6 个月时进行了更详细的评估。在 2004 年至 2007 年间，228 例患者接受了 CRT 植入术（64 例 CRT 起搏器，164 例 CRT 除颤器）。在基线时，与标准 LVtip 至 LVring 相比，电子重新编程以确定替代配置发现 80 例患者（35%）的起搏阈值降低了≥1.0V。在 17 例具有 LVtip 至 LVring 配置且高起搏阈值（>5.0V）的患者中，16 例可通过电子重新定位降低>1.0V（94%），11 例可通过电子重新定位降低>2.0V（65%），无需重新定位导联。在植入时，有 48 例患者使用标准 LVtip 至 LVring 配置时在最大起搏输出以下出现膈神经刺激（21%）。在 37 例（77%）中，至少有一种其他配置无膈神经刺激，从而避免了导联修订的需要。
电子重新定位是 CRT 患者管理的重要工具，可帮助降低阈值、避免膈神经刺激，并防止因 LV 导联重新定位而进行不必要的再次手术。
