Grattan Michael, Mertens Luc, Grosse-Wortmann Lars, Friedberg Mark K, Cifra Barbara, Dragulescu Andreea
Department of Paediatrics, Division of Cardiology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada; Department of Paediatrics, LHSC Children's Hospital, University of Western Ontario, London, Ontario, Canada.
Department of Paediatrics, Division of Cardiology, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
J Am Soc Echocardiogr. 2018 Dec;31(12):1288-1296. doi: 10.1016/j.echo.2018.07.018. Epub 2018 Oct 17.
In normal left ventricles, clockwise basal rotation and counterclockwise apical rotation result in systolic torsion. Torsion is important for contractile efficiency and may be especially important in single-ventricle (SV) physiology. However, little is known about torsion in patients with SVs. The aim of this study was to measure torsion in SVs and to determine its relationship with other measures of ventricular function. The hypothesis was that torsion would be decreased in all SVs, most significantly in single right ventricles, and that it would correlate with other measures of ventricular function.
A prospective cross-sectional study was performed in 61 patients with SVs undergoing pre- or post-Fontan cardiac catheterization and 30 matched control subjects. Echocardiography, catheterization, and cardiac magnetic resonance imaging were performed under the same anesthetic. Torsion and strain were measured using speckle-tracking echocardiography. Intracardiac pressures, pulmonary vascular resistance, and cardiac magnetic resonance imaging-derived ventricular volume and ejection fraction were measured.
Thirty-five patients were left ventricular dominant, 15 were right ventricular dominant, 10 were codominant, and one had indeterminate morphology. Thirty-seven patients were pre-Fontan and 24 were post-Fontan. Patients with SVs had similar overall torsion as control subjects (median, 1.7°/cm vs 1.65°/cm; P = NS); however, they had decreased or reversed basal rotation (-0.32°/cm vs -0.93°/cm, P < .0001) and increased apical rotation (1.45°/cm vs 1.06°/cm, P = .0065). There were no differences on the basis of ventricular dominance or palliative stage. Torsion did not significantly correlate with other echocardiographic, catheter-based, or cardiac magnetic resonance imaging measures of cardiac function.
Single left and right ventricles exhibit preserved torsion, mainly because of preserved or increased apical rotation. Possible mechanisms of torsion in single right ventricles include myofiber remodeling and altered ventricular-ventricular interactions. Understanding myocardial deformation in SVs will improve the ability to interpret ventricular function in this precarious population.
在正常左心室中，基底顺时针旋转和心尖逆时针旋转导致收缩期扭转。扭转对于收缩效率很重要，在单心室（SV）生理学中可能尤为重要。然而，关于SV患者的扭转情况知之甚少。本研究的目的是测量SV的扭转，并确定其与心室功能其他指标的关系。假设是所有SV的扭转都会降低，在单右心室中最为显著，并且它将与心室功能的其他指标相关。
对61例接受Fontan手术前后心脏导管检查的SV患者和30例匹配的对照受试者进行了一项前瞻性横断面研究。在相同麻醉下进行超声心动图、导管检查和心脏磁共振成像。使用斑点追踪超声心动图测量扭转和应变。测量心内压力、肺血管阻力以及心脏磁共振成像得出的心室容积和射血分数。
35例患者为左心室优势型，15例为右心室优势型，10例为共优势型，1例形态不确定。37例患者处于Fontan手术前，24例处于Fontan手术后。SV患者的总体扭转与对照受试者相似（中位数，1.7°/cm对1.65°/cm；P =无显著差异）；然而，他们的基底旋转降低或反转（-0.32°/cm对-0.93°/cm，P <.0001），心尖旋转增加（1.45°/cm对1.06°/cm，P =.0065）。在心室优势或姑息阶段方面没有差异。扭转与其他超声心动图、基于导管的或心脏磁共振成像的心脏功能指标没有显著相关性。
单左心室和单右心室表现出保留的扭转，主要是因为心尖旋转得以保留或增加。单右心室扭转的可能机制包括肌纤维重塑和心室间相互作用改变。了解SV中的心肌变形将提高解释这一脆弱人群心室功能的能力。
