Friedberg Mark K, Silverman Norman H
Division of Pediatric Cardiology, Department of Pediatrics, Lucille Packard Children's Hospital and Stanford University, Stanford, California, USA.
J Am Soc Echocardiogr. 2007 Jun;20(6):749-55. doi: 10.1016/j.echo.2006.11.014.
Right ventricular (RV) function is an important determinant of clinical status in children with hypoplastic left heart syndrome (HLHS). However, assessment of RV function remains challenging because of its complex morphology. We investigated the S/D duration ratio in children with HLHS as a novel index of global RV function.
We measured systolic (S) and diastolic (D) duration using tricuspid regurgitation duration from Doppler flow, to calculate the S/D ratio in 33 children with HLHS and 33 control subjects matched for age and sex. We compared the S/D ratio between patients with HLHS and control subjects, between patients with HLHS and normal and abnormal RV function, and between patients with HLHS at different stages of palliation. We further correlated the S/D ratio with catheterization data.
Patients and control subjects were well matched for age (3.12 +/- 4.5 vs 3 +/- 4.5 years, not significant) sex, and heart rate (cycle length 524 +/- 179 vs 575 +/- 162 milliseconds, not significant). Patients with HLHS had a significantly higher S/D ratio than control subjects (1.65 +/- 0.85 vs 0.85 +/- 0.2, P < .0001). The S/D ratio became increasingly elevated in HLHS at higher heart rates, but not in control subjects. The S/D ratio was significantly higher in patients with HLHS and decreased RV function as compared with patients with HLHS and normal RV function (2.2 +/- 0.7 vs 1.5 +/- 0.47, P = .006), and significantly increased in patients with Norwood stage 1 versus patients with Norwood stages 2 and 3 HLHS (2.16 vs 1.4 and 1.32, respectively, P < .01 and P < .001, respectively). The S/D ratio did not correlate with catheterization-derived RV end-D pressure or cardiac index.
Patients with HLHS have an increased S/D ratio as a result of a shortened D and prolonged S. Measurement of the S/D duration ratio using Doppler flow is a novel method to augment assessment of global RV function in HLHS.
右心室（RV）功能是左心发育不全综合征（HLHS）患儿临床状况的重要决定因素。然而，由于右心室形态复杂，对其功能的评估仍然具有挑战性。我们研究了HLHS患儿的S/D持续时间比，将其作为评估右心室整体功能的一个新指标。
我们利用多普勒血流测得的三尖瓣反流持续时间来测量收缩期（S）和舒张期（D）的持续时间，计算33例HLHS患儿及33例年龄和性别相匹配的对照者的S/D比值。我们比较了HLHS患儿与对照者之间、HLHS患儿中右心室功能正常和异常者之间以及HLHS患儿在不同姑息治疗阶段的S/D比值。我们还将S/D比值与心导管检查数据进行了相关性分析。
患者和对照者在年龄（3.12±4.5岁对3±4.5岁，无显著差异）、性别和心率（心动周期长度524±179毫秒对575±162毫秒，无显著差异）方面匹配良好。HLHS患儿的S/D比值显著高于对照者（1.65±0.85对0.85±0.2，P<.0001）。在HLHS患儿中，心率越高，S/D比值升高越明显，但对照者并非如此。与右心室功能正常的HLHS患儿相比，右心室功能降低的HLHS患儿的S/D比值显著更高（2.2±0.7对1.5±0.47，P=.006），与Norwood 1期HLHS患儿相比，Norwood 2期和3期HLHS患儿的S/D比值显著升高（分别为2.16对1.4和1.32，P分别<.01和P<.001）。S/D比值与心导管检查测得的右心室舒张末期压力或心脏指数无关。
HLHS患儿因舒张期缩短和收缩期延长导致S/D比值升高。利用多普勒血流测量S/D持续时间比是一种增强HLHS患儿右心室整体功能评估手段的新方法。
