Friedberg Mark K, Silverman Norman H, Dubin Anne M, Rosenthal David N
Division of Pediatric Cardiology, Stanford University, Stanford, California 94304, USA.
J Am Soc Echocardiogr. 2007 Sep;20(9):1073-9. doi: 10.1016/j.echo.2007.02.015. Epub 2007 Jun 12.
Mechanical dyssynchrony predicts response to cardiac resynchronization therapy in adults with heart failure. Children with hypoplastic left heart syndrome (HLHS) are susceptible to right ventricular (RV) failure; however, mechanical dyssynchrony has not been studied in this population with newly available methodologies. We investigated RV mechanical dyssynchrony in children with HLHS using vector velocity imaging.
We used vector velocity imaging to quantify the SD of time to peak velocity, strain, and strain rate among 6 RV segments to define intraventricular RV synchrony in 16 children with HLHS and RV and left ventricular (LV) synchrony in 16 healthy age-matched control subjects. We further investigated relations between QRS duration and mechanical dyssynchrony and between mechanical dyssynchrony and systolic function.
Children with HLHS had significant RV mechanical dyssynchrony versus LV and RV control subjects (strain 37 +/- 35 vs 8 +/- 8 milliseconds, P = .003 [LV], 9 +/- 11 milliseconds, P = .005 [RV]; strain rate 31 +/- 37 vs 10 +/- 13 milliseconds, P = .04 [LV], 14 +/- 15 milliseconds, P = .09 [RV]). There was no significant relationship between QRS duration and mechanical dyssynchrony and no obvious relation between the degree of mechanical dyssynchrony and the RV fractional area of change.
Children with HLHS have RV mechanical dyssynchrony unrelated to surface electrocardiographic QRS duration. This may contribute to RV dysfunction and may indicate the usefulness of cardiac resynchronization therapy in this population.
机械性不同步可预测成人心力衰竭患者对心脏再同步治疗的反应。左心发育不全综合征（HLHS）患儿易发生右心室（RV）衰竭；然而，尚未采用最新方法对该人群的机械性不同步进行研究。我们使用矢量速度成像技术研究了HLHS患儿的右心室机械性不同步情况。
我们使用矢量速度成像技术量化了16例HLHS患儿6个右心室节段达到峰值速度、应变及应变率的时间标准差，以定义右心室内同步性，并在16例年龄匹配的健康对照受试者中定义右心室与左心室（LV）同步性。我们进一步研究了QRS波时限与机械性不同步之间的关系以及机械性不同步与收缩功能之间的关系。
与左心室及右心室对照受试者相比，HLHS患儿存在显著的右心室机械性不同步（应变37±35 vs 8±8毫秒，P = 0.003[左心室]，9±11毫秒，P = 0.005[右心室]；应变率31±37 vs 10±13毫秒，P = 0.04[左心室]，14±15毫秒，P = 0.09[右心室]）。QRS波时限与机械性不同步之间无显著关系，机械性不同步程度与右心室面积变化分数之间也无明显关系。
HLHS患儿存在与体表心电图QRS波时限无关的右心室机械性不同步。这可能导致右心室功能障碍，并可能提示心脏再同步治疗对该人群有用。
