Sheehan Florence H, Ge Shuping, Vick G Wesley, Urnes Kara, Kerwin William S, Bolson Edward L, Chung Taylor, Kovalchin John P, Sahn David J, Jerosch-Herold Michael, Stolpen Alan H
University of Washington, Seattle, Washington, USA.
Am J Cardiol. 2008 Jan 1;101(1):107-13. doi: 10.1016/j.amjcard.2007.07.080.
Understanding of right ventricular (RV) remodeling is needed to elucidate the mechanism of RV dysfunction in the overloaded right ventricle, but is hampered by the chamber's complex shape. We imaged 15 patients with repaired tetralogy of Fallot (TOF) and 8 normal subjects by magnetic resonance imaging in long- and short-axis views. We reconstructed the right ventricles in 3 dimensions using the piecewise smooth subdivision surface method. Shape was analyzed from cross-sectional contours generated by intersecting the right ventricle with 20 planes evenly spaced from apex to tricuspid annulus. Patients with TOF had dilated right ventricles compared with normal (end-diastolic volume index 216 +/- 99 vs 81 +/- 16 ml/m(2), p <0.001) but near-normal function (ejection fraction 40 +/- 9% vs 48 +/- 12%, respectively, p = NS). RV shape in patients with TOF differed from normal subjects in several ways. First, the right ventricle had a larger normalized cross-sectional area in patients with TOF (p <0.01 in apical planes). Second, the cross-sectional shape was rounder in patients with TOF (p <0.05 in apical planes). Also, the interventricular septum underwent relatively less enlargement so that it comprised only 27 +/- 4% of total RV surface area in patients with TOF, compared with 33 +/- 2% in normal subjects (p = 0.0001). In addition, the right ventricle in patients with TOF exhibited bulging basal to the tricuspid valve (4 +/- 4% of total RV length), unlike normals (1 +/- 2%, p <0.001). This basal bulging was amplified by tilting of the tricuspid annulus (29 +/- 11 degrees vs 15 +/- 7 degrees , respectively, p <0.005). In conclusion, the right ventricle remodels in several directions rather than following a shape continuum. Characterization of RV remodeling from 3-dimensional reconstructions provides novel insights.
为阐明右心室（RV）负荷过重时右心室功能障碍的机制，需要了解右心室重构，但由于该腔室形状复杂，这一研究受到阻碍。我们对15例法洛四联症（TOF）修复术后患者和8名正常受试者进行了磁共振成像，获取长轴和短轴视图。我们使用分段光滑细分曲面法对右心室进行三维重建。通过将右心室与从心尖到三尖瓣环均匀间隔的20个平面相交产生的横截面轮廓来分析形状。与正常受试者相比，TOF患者的右心室扩张（舒张末期容积指数分别为216±99与81±16ml/m²，p<0.001），但功能接近正常（射血分数分别为40±9%与48±12%，p=无显著差异）。TOF患者的右心室形状在几个方面与正常受试者不同。首先，TOF患者右心室的标准化横截面积更大（心尖平面p<0.01）。其次，TOF患者的横截面形状更圆（心尖平面p<0.05）。此外，室间隔扩大相对较少，因此在TOF患者中，室间隔仅占右心室总面积的27±4%，而正常受试者为33±2%（p=0.0001）。此外，与正常人不同（1±2%，p<0.001），TOF患者的右心室在三尖瓣下方呈膨出（占右心室总长度的4±4%）。三尖瓣环倾斜加剧了这种底部膨出（分别为29±11度与15±7度，p<0.005）。总之，右心室在几个方向上进行重构，而不是遵循形状连续变化。从三维重建中对右心室重构进行表征提供了新的见解。
