Slim George, Pagano Joseph, Punithakumar Kumaradevan, Noga Michelle, Tham Edythe
Stollery Children's Hospital, Divisions of Pediatric Cardiology and Diagnostic Imaging, University of Alberta, Edmonton, AB, Canada.
Servier Virtual Cardiac Centre, Mazankowski Alberta Heart Institute and Department of Radiology and Diagnostic Imaging, University of Alberta, Edmonton, AB, Canada.
Cardiol Young. 2025 Jul;35(7):1335-1343. doi: 10.1017/S1047951125101212. Epub 2025 Aug 1.
Pulmonary regurgitation leading to right ventricular enlargement may occur after repaired tetralogy of Fallot (rTOF) or balloon dilation for pulmonary valve stenosis. Cardiac magnetic resonance imaging (CMR) guidelines to identify the timing of valve replacement in rTOF are not necessarily applicable to isolated pulmonary regurgitation. This study aims to compare deformation parameters of isolated pulmonary regurgitation and rTOF at comparable right ventricular volume loads.
Adopting a quantitative retrospective analytic framework, CMR was performed in 44 patients (0-30 years), 22 in each of the isolated pulmonary regurgitation and rTOF study arms, matched for age (±12 months), and Right ventricular end-diastolic volume -score (±1). Right ventricular longitudinal strain/strain rate and circumferential strain/strain rate were measured. Comparisons between groups were analysed using two-tailed -tests and one-way ANOVA.
Both groups showed predominance of longitudinal over circumferential strain. Circumferential strain was significantly greater in rTOF compared to isolated pulmonary regurgitation (-26.5% versus -22.3%, < 0.05). Longitudinal strain did not differ between groups. The longitudinal:circumferential strain ratio was significantly lower in rTOF compared to isolated pulmonary regurgitation (1.24 versus 1.53, = 0.05). Circumferential and longitudinal strain rates did not differ between groups.
The right ventricles in rTOF demonstrate greater reliance on circumferential strain in response to increased volumes. The decrease in longitudinal:circumferential strain ratio suggests rTOF right ventricles display a greater adaptive response to the volume load than isolated pulmonary regurgitation, highlighting the importance of the relative contributions of both circumferential and longitudinal strain in order to understand the mechanisms of right ventricular dysfunction in pulmonary regurgitation.
法洛四联症修复术后（rTOF）或肺动脉瓣狭窄球囊扩张术后可能发生导致右心室扩大的肺动脉反流。用于确定rTOF中瓣膜置换时机的心脏磁共振成像（CMR）指南不一定适用于孤立性肺动脉反流。本研究旨在比较在可比的右心室容量负荷下孤立性肺动脉反流和rTOF的变形参数。
采用定量回顾性分析框架，对44例（0至30岁）患者进行CMR检查，孤立性肺动脉反流和rTOF研究组各22例，年龄匹配（±12个月），右心室舒张末期容积评分匹配（±1）。测量右心室纵向应变/应变率和圆周应变/应变率。组间比较采用双尾检验和单因素方差分析。
两组均显示纵向应变大于圆周应变。与孤立性肺动脉反流相比，rTOF中的圆周应变显著更大（-26.5%对-22.3%，P<0.05）。两组间纵向应变无差异。与孤立性肺动脉反流相比，rTOF中的纵向：圆周应变率显著更低（1.24对1.53，P = 0.05）。两组间圆周和纵向应变率无差异。
rTOF中的右心室在应对容量增加时对圆周应变的依赖性更大。纵向：圆周应变率的降低表明rTOF右心室对容量负荷的适应性反应比孤立性肺动脉反流更大，突出了圆周应变和纵向应变的相对贡献在理解肺动脉反流中右心室功能障碍机制方面的重要性。
