McCrary Andrew W, Collins Sydney D, Spector Zebulon Z, Kropf P Andrea, Barker Piers C A, Kisslo Joseph, Forsha Daniel E
Division of Pediatric Cardiology, Department of Pediatrics, Duke University Medical Center, Durham, NC, United States.
Divison of Cardiology, Department of Medicine, Duke University Medical Center, Durham, NC, United States.
Front Pediatr. 2025 Jan 10;12:1443924. doi: 10.3389/fped.2024.1443924. eCollection 2024.
In adolescents and adults with tetralogy of Fallot (TOF), right ventricle (RV) electromechanical dyssynchrony (EMD) due to right bundle branch block (RBBB) is associated with reduced exercise capacity and RV dysfunction. While the development of RBBB following surgical repair of tetralogy of Fallot (rTOF) is a frequent sequela, it is not known whether EMD is present in every patient immediately following rTOF. The specific timing of the onset of RBBB following rTOF therefore provides an opportunity to assess whether acute RBBB is associated with the simultaneous acquisition of EMD.
Transthoracic echocardiography with speckle tracking analysis for RV global longitudinal strain (GLS) and 12-lead ECG were performed prospectively on 20 infants following rTOF. Three apical RV views were obtained using analogous imaging planes to the standard LV views to provide a comprehensive evaluation. Regional RV GLS patterns were categorized as synchronous, EMD, or indeterminate. EMD was defined as an early-terminated septal contraction opposed by early stretch and post-systolic peak contraction in the activation delayed RV free wall. An indeterminate pattern was defined as a lack of fully synchronous contraction of all segments but not meeting criteria for EMD. Pre-rTOF echocardiograms and ECGs were analyzed to confirm the presence of synchronous contraction and a normal QRS pattern and duration prior to surgery.
Twenty TOF infants (median age 87 days; 8 days from surgery to post-rTOF evaluation) demonstrated QRSd prolongation following rTOF (pre-rTOF 58 ± 9 ms; post-rTOF 97 ± 14 ms; < 0.001) with new RBBB morphology in all but one patient. All pre-rTOF RV strain patterns were synchronous. Post-rTOF RV strain analysis showed EMD in 25% (5/20) and an indeterminate pattern in 40% (8/20) with the remaining 35% (7/20) maintaining a synchronous pattern, including the patient without RBBB. The EMD group had the lowest RV GLS following repair ( = 0.006).
Acquisition of acute QRS prolongation in a RBBB pattern is near-universal following rTOF but without matched or identical patterns of dyssynchrony, suggesting that variations in the time from electrical to electromechanical dyssynchrony potentially caused by differences in right bundle branch anatomy and injury may be relevant to electromechanical outcomes.
在法洛四联症（TOF）的青少年和成人患者中，右束支传导阻滞（RBBB）导致的右心室（RV）机电不同步（EMD）与运动能力下降和RV功能障碍有关。虽然法洛四联症修复术（rTOF）后RBBB的发生是常见的后遗症，但尚不清楚rTOF后每位患者是否立即存在EMD。因此，rTOF后RBBB发生的具体时间为评估急性RBBB是否与同时出现的EMD相关提供了机会。
对20例rTOF后的婴儿进行前瞻性经胸超声心动图检查，并采用散斑追踪分析测量RV整体纵向应变（GLS），同时记录12导联心电图。使用与标准左心室视图类似的成像平面获取三个心尖RV视图，以进行全面评估。区域RV GLS模式分为同步、EMD或不确定。EMD定义为间隔收缩提前终止，同时激活延迟的RV游离壁出现早期拉伸和收缩期后峰值收缩。不确定模式定义为所有节段缺乏完全同步收缩，但不符合EMD标准。分析rTOF前的超声心动图和心电图，以确认手术前存在同步收缩以及正常的QRS模式和持续时间。
20例TOF婴儿（中位年龄87天；从手术到rTOF后评估为8天）在rTOF后出现QRSd延长（rTOF前58±9毫秒；rTOF后97±14毫秒；<0.001），除1例患者外，所有患者均出现新的RBBB形态。所有rTOF前的RV应变模式均为同步。rTOF后的RV应变分析显示，25%（5/20）为EMD，40%（8/20）为不确定模式，其余35%（7/20）保持同步模式，包括无RBBB的患者。EMD组修复后的RV GLS最低（=0.006）。
rTOF后几乎普遍出现RBBB模式的急性QRS延长，但不同步模式不匹配或不完全相同，这表明右束支解剖结构和损伤差异可能导致从电不同步到机电不同步的时间变化，这可能与机电结果相关。
