From the St. Vincent Medical Group, Indianapolis, IN.
Circ Arrhythm Electrophysiol. 2014 Aug;7(4):640-4. doi: 10.1161/CIRCEP.113.000999. Epub 2014 Jul 11.
Definitive diagnosis of bilateral bundle-branch delay/block may be made when catheter-induced right bundle-branch block (RBBB) develops in patients with baseline left bundle-branch (LBB) block. We hypothesized that a RBBB pattern with absent S waves in leads I and aVL will identify bilateral bundle-branch delay/block.
Fifty patients developing transient RBBB pattern in lead V1 during right heart catheterization were studied. Patients were grouped according to whether the baseline ECG demonstrated a normal QRS, left fascicular blocks, or LBB block pattern. The RBBB morphologies in each group were compared. The prevalence of bilateral bundle-branch delay/block pattern was examined in our hospital ECG database. All patients with baseline normal QRS complexes (n=30) or left fascicular blocks (4 anterior, 5 posterior) developed a typical RBBB pattern. Among the 11 patients with a baseline LBB block pattern, 7 developed an atypical RBBB pattern with absent S waves in leads I and aVL and the remaining 4 demonstrated a typical RBBB. The absence of S waves in leads I and aVL during RBBB was 100% specific and 64% sensitive for the presence of pre-existing LBB block. Among the consecutive 2253 hospitalized patients with RBBB, 34 (1.5%) had the bilateral bundle-branch delay/block pattern.
An ECG pattern of RBBB in lead V1 with absent S wave in leads I and aVL indicates concomitant LBB delay. Pure RBBB and bifascicular blocks are associated with S waves in leads I and aVL.
当基线存在左束支（LBB）阻滞的患者出现导管诱导的右束支阻滞（RBBB）时，可以明确诊断双侧束支传导延迟/阻滞。我们假设，在 I 导联和 aVL 导联中 S 波缺失的 RBBB 形态将识别双侧束支传导延迟/阻滞。
在右心导管检查中，研究了 50 例在 V1 导联出现短暂 RBBB 形态的患者。根据基线心电图是否显示正常 QRS 波、左束支分支阻滞或 LBB 阻滞模式，将患者分组。比较了每组的 RBBB 形态。在我院心电图数据库中检查了双侧束支传导延迟/阻滞模式的患病率。所有基线 QRS 综合波正常的患者（n=30）或左束支分支阻滞（4 个前支，5 个后支）均出现典型的 RBBB 形态。在 11 例基线 LBB 阻滞模式的患者中，7 例出现 I 导联和 aVL 导联 S 波缺失的非典型 RBBB 形态，其余 4 例表现为典型 RBBB。在 RBBB 时 I 导联和 aVL 导联 S 波缺失的特异性为 100%，对存在预先存在的 LBB 阻滞的敏感性为 64%。在连续 2253 例 RBBB 住院患者中，有 34 例（1.5%）存在双侧束支传导延迟/阻滞模式。
V1 导联 RBBB 伴 I 导联和 aVL 导联 S 波缺失的心电图模式表明同时存在 LBB 延迟。单纯 RBBB 和双分支阻滞与 I 导联和 aVL 导联的 S 波相关。
