The Labatt Family Heart Centre, The Hospital for Sick Children, Toronto, Ontario, Canada; Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada.
The Labatt Family Heart Centre, The Hospital for Sick Children, Toronto, Ontario, Canada.
J Am Soc Echocardiogr. 2018 Jul;31(7):822-830. doi: 10.1016/j.echo.2018.03.012.
Electromechanical dyssynchrony occurs ubiquitously following tetralogy of Fallot (TOF) repair, manifesting electrically as a wide QRS duration and mechanically as a right-sided septal/apical flash. Early septal activation and prestretch of the right ventricular (RV) basal lateral wall followed by its postsystolic shortening contributes to inefficient RV mechanics. However, a right-sided septal flash is a dichotomous finding, and the severity of RV dyssynchrony as a continuous spectrum in relationship to RV dysfunction and clinical outcomes in patients with repaired TOF has not been studied. The aim of this study was to quantify the severity of electromechanical dyssynchrony in relation to RV remodeling and clinical outcomes in a pediatric cohort following TOF repair.
A retrospective analysis was performed in 81 children with RV volume loading after TOF repair, aged 13.6 ± 2.9 years, and compared with 50 matched control subjects.
Patients had higher RV basal-lateral prestretch and postsystolic strain amplitude and duration, RV mechanical dispersion, and basal lateral-septal wall delay compared with control subjects (P < .001 for all). All intra-RV dyssynchrony timing parameters were associated with reduced cardiac magnetic resonance-derived RV ejection fraction and/or echocardiography-derived RV longitudinal strain. Prestretch duration as a percentage of total shortening time and RV basal lateral-to-midseptal delay were independently associated with RV dysfunction. Postsystolic strain amplitude was higher in patients with ventricular arrhythmias compared with arrhythmia-free patients (7.8% [4.2%-13%] vs 2.0% [0%-12.5%], P = .03).
RV prestretch duration, postsystolic strain, and RV lateral-septal delay quantify RV electromechanical dyssynchrony severity and reflect the underlying pathophysiology. The prestretch duration percentage and RV basal lateral-to-midseptal delay were independently associated with RV dysfunction, potentially providing a clinical tool to quantify RV electromechanical dyssynchrony.
法洛四联症（TOF）修复后普遍存在机电不同步，表现在电上为宽 QRS 时限，表现在机械上为右室间隔/心尖闪光。早期的室间隔激活和右心室（RV）基底外侧壁的预拉伸，随后是其收缩后缩短，导致 RV 机械效率低下。然而，右室间隔闪光是一个二分法的发现，并且在修复的 TOF 患者中，与 RV 功能障碍和临床结果相关的 RV 不同步的严重程度作为连续谱，尚未得到研究。本研究旨在量化 TOF 修复后 RV 重构与临床结果相关的机电不同步的严重程度。
对 81 例 RV 容量负荷后 TOF 修复的儿科患者进行回顾性分析，年龄 13.6 ± 2.9 岁，并与 50 例匹配的对照组进行比较。
与对照组相比，患者的 RV 基底外侧预拉伸和收缩后应变幅度和持续时间、RV 机械弥散以及基底外侧-间隔壁延迟更高（所有 P <.001）。所有 RV 内不同步的时间参数均与心脏磁共振衍生的 RV 射血分数和/或超声心动图衍生的 RV 纵向应变降低相关。预拉伸持续时间占总缩短时间的百分比和 RV 基底外侧至中隔壁延迟与 RV 功能障碍独立相关。与无心律失常患者相比，心律失常患者的收缩后应变幅度更高（7.8%[4.2%-13%]与 2.0%[0%-12.5%]，P =.03）。
RV 预拉伸持续时间、收缩后应变和 RV 外侧-间隔壁延迟定量 RV 机电不同步的严重程度，并反映潜在的病理生理。预拉伸持续时间百分比和 RV 基底外侧至中隔壁延迟与 RV 功能障碍独立相关，可能为定量 RV 机电不同步提供了一种临床工具。
