Cardiac Electrophysiology Program, Cardiovascular Division, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.
J Cardiovasc Electrophysiol. 2018 Nov;29(11):1515-1522. doi: 10.1111/jce.13747. Epub 2018 Oct 8.
Differentiation of right versus left ventricular outflow tract (RVOT vs. LVOT) arrhythmia origin with left bundle branch block right inferior axis (LBRI) morphology is relevant to ablation planning and risk discussion. Our aim was to determine if lead I R-wave amplitude is useful for differentiation of RVOT from LVOT arrhythmias with LBRI morphology.
The R-wave amplitude in lead I was measured in a retrospective cohort of 75 consecutive patients with LBRI pattern ventricular arrhythmias (VAs) successfully ablated from the RVOT (n = 54), LVOT (n = 16), or the anterior interventricular vein (AIV; n = 5). The optimal R-wave threshold was identified and diagnostic indices were compared with the previously reported transitional zone (TZ) index and V2S/V3R index.
An R-wave amplitude greater than or equal to 0.1 mV predicted LVOT origin with 75% sensitivity and 98.2% specificity. In comparison, the TZ and V2S/V3R indices had 50% and 68.8% sensitivity, and 75.9% and 88.9% specificity, respectively, for predicting LVOT origin. The area under the curve (AUC) was 0.85 for lead I R-wave amplitude, 0.87 for V2S/V3R, and 0.72 for the TZ index. Of 36 cases with QS in lead I, 30 (83.3%) were from the anterior RVOT, three (8.3%) from the LVOT, and three (8.3%) from the AIV.
The presence of R-wave amplitude in lead I (≥0.1 mV) is a simple and useful criterion to identify LVOT cusp or endocardium focus in LBRI arrhythmias. A QS pattern in lead I suggests an origin in the anterior RVOT, or less commonly the adjacent LV summit.
具有左束支传导阻滞右下轴（LBRI）形态的右心室流出道（RVOT）与左心室流出道（LVOT）心律失常起源的鉴别对于消融计划和风险讨论很重要。我们的目的是确定 I 导联 R 波振幅是否可用于鉴别具有 LBRI 形态的 RVOT 与 LVOT 心律失常。
我们回顾性分析了 75 例连续的具有 LBRI 模式室性心律失常（VA）的患者，这些患者均成功地从 RVOT（n=54）、LVOT（n=16）或前间隔静脉（AIV；n=5）消融。测量 I 导联的 R 波振幅，并确定最佳 R 波阈值，并与之前报道的过渡区（TZ）指数和 V2S/V3R 指数进行比较。
R 波振幅大于或等于 0.1 mV 预测 LVOT 起源的敏感度为 75%，特异性为 98.2%。相比之下，TZ 和 V2S/V3R 指数预测 LVOT 起源的敏感度分别为 50%和 68.8%，特异性分别为 75.9%和 88.9%。I 导联 R 波振幅的曲线下面积（AUC）为 0.85，V2S/V3R 的 AUC 为 0.87，而 TZ 指数的 AUC 为 0.72。在 I 导联出现 QS 的 36 例患者中，30 例（83.3%）起源于 RVOT 前嵴，3 例（8.3%）起源于 LVOT，3 例（8.3%）起源于 AIV。
I 导联存在 R 波振幅（≥0.1 mV）是一种简单而有用的标准，可用于识别 LBRI 心律失常中的 LVOT 嵴或心内膜起源。I 导联出现 QS 图形提示起源于 RVOT 前嵴，或较少见的起源于相邻的 LV 心尖。
