Tada Hiroshi
Division of Cardiology, Gunma Prefectural Cardiovascular Center, Maebashi, Gunma, Japan.
Indian Pacing Electrophysiol J. 2005 Apr 1;5(2):96-105.
Idiopathic outflow tract arrhythmias (ventricular tachycardias or symptomatic premature ventricular contractions; OT-VT/PVCs) can originate from the left ventricular (LV) epicardium (Epi-VT/PVCs), and radiofrequency (RF) energy applications from the aortic sinus of Valsalva can eliminate Epi-VT/PVCs in selected patients. Among the various ECG findings, the R-wave duration index and R/S amplitude index in leads V1 or V2 are useful for identifying Epi-VT/PVCs, and the Q-wave ratio of leads aVL to aVR and S-wave amplitude in lead V1 are useful for differentiating between an Epi-VT/PVC originating from the LV epicardium remote from the left sinus of Valsalva (LSV) and that from the LSV. Tissue tracking imaging is a promising modality for identifying the origin of OT-VT/PVCs and for differentiating between an Epi-VT/PVC originating from the LV epicardium remote from the LSV and that from the LSV. If the origin of the Epi-VT/PVC is identified within the LSV, coronary and aortic angiography should be performed to assess the anatomic relationships between the Epi-VT/PVC origin and coronary arteries and aortic valve before the RF energy delivery. To avoid potential complications, RF ablation should be performed at the LSV using a maximum power of 35 watts and maximum temperature of 55 degrees C. Epicardial mapping through the coronary venous system and the presence of potentials recorded from the ablation site within the LSV and their changes before and after the RF energy applications may be useful for diagnosing Epi-VT/PVCs or predicting a successful catheter ablation from the LSV.
特发性流出道心律失常(室性心动过速或有症状的室性早搏;OT-VT/PVCs)可起源于左心室(LV)心外膜(Epi-VT/PVCs),在部分患者中,经Valsalva窦进行射频(RF)能量施加可消除Epi-VT/PVCs。在各种心电图表现中,V1或V2导联的R波时限指数和R/S振幅指数有助于识别Epi-VT/PVCs,aVL导联与aVR导联的Q波比值以及V1导联的S波振幅有助于区分起源于远离左Valsalva窦(LSV)的左心室心外膜的Epi-VT/PVCs和起源于LSV的Epi-VT/PVCs。组织追踪成像对于识别OT-VT/PVCs的起源以及区分起源于远离LSV的左心室心外膜的Epi-VT/PVCs和起源于LSV的Epi-VT/PVCs是一种很有前景的方法。如果在LSV内确定了Epi-VT/PVC的起源,在进行RF能量传递之前,应进行冠状动脉和主动脉血管造影,以评估Epi-VT/PVC起源与冠状动脉和主动脉瓣之间的解剖关系。为避免潜在并发症,应在LSV处进行RF消融,最大功率为35瓦,最高温度为55摄氏度。通过冠状静脉系统进行心外膜标测以及在LSV内消融部位记录到的电位及其在RF能量施加前后的变化,可能有助于诊断Epi-VT/PVCs或预测从LSV进行导管消融是否成功。