Objective

Combining stress echocardiography with strain analysis is a promising approach for early detection of subclinical cardiac dysfunction not apparent at rest. Data on normal myocardial strain and strain rate (SR) response to exercise in adolescents and young adults are contradictory and limited. The aim of this study was to propose a standardized protocol for semisupine bicycle stress echocardiography and to provide corresponding reference values of left ventricular (LV) two-dimensional speckle-tracking echocardiography (2D STE) strain and SR in adolescents and young adults.

Methods

Fifty healthy adolescents and young adults (mean age, 17.8 ± 3.2 years, 44% female) were prospectively assessed. Images were acquired at rest, low stress, submaximal stress, and during recovery. Optimal image quality for offline strain analysis was pursued, and image quality was rated. Global longitudinal strain and SR from apical four-/two-/three-chamber views and short-axis circumferential strain and SR were analyzed using vendor-independent software. Interobserver variability was assessed.

Results

Strain and SR increased during progressive exercise stress. Mean LV global longitudinal strain was −20.4% ± 1.3%, SR −1.1 ± 0.15/sec at rest (heart rate, 79.4 ± 12.0 beats/minute), increasing to −22.6% ± 1.6% and −1.5 ± 0.16/sec at low stress level (heart rate, 117.1 ± 8.7 beats/minute) and −23.7% ± 1.1% and −1.9 ± 0.29/sec at submaximal stress level (heart rate, 154.2 ± 7.0 beats/minute), respectively, returning to −20.6% ± 1.4% and −1.2 ± 0.16/sec postexercise (heart rate, 90.1 ± 9.4 beats/minute). Restriction on submaximal stress level ensured adequate image quality for 2D STE strain analysis. Interobserver variability for strain was acceptable even during submaximal stress.

Conclusions

This study provides a systematic, standardized protocol and corresponding reference data for 2D LV STE-derived strain and SR during semisupine bicycle exercise testing in adolescents and young adults. According to our results, global longitudinal strain and SR appear to be the most comprehensible parameters for cross-sectional studies.

中文翻译：

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健康青少年和年轻成人在次最大半仰卧自行车运动应激超声心动图期间的左心室应变和应变率：系统方案和参考值。

客观的

将负荷超声心动图与应变分析相结合是一种早期检测静息时不明显的亚临床心功能障碍的有前途的方法。青少年和年轻成人对运动的正常心肌应变和应变率 (SR) 反应的数据相互矛盾且有限。本研究的目的是提出半卧位自行车负荷超声心动图的标准化方案，并为青少年和年轻成人的左心室 (LV) 二维斑点跟踪超声心动图 (2D STE) 应变和 SR 提供​​相应的参考值。

方法

前瞻性评估了 50 名健康的青少年和年轻人（平均年龄，17.8 ± 3.2 岁，44% 为女性）。在休息、低压力、次最大压力和恢复期间获取图像。追求离线应变分析的最佳图像质量，并对图像质量进行评级。使用独立于供应商的软件分析来自顶端四腔/两腔/三腔视图的全局纵向应变和 SR 以及短轴周向应变和 SR。评估了观察者间的变异性。

结果

在渐进式运动压力期间，应变和 SR 增加。平均 LV 整体纵向应变为 -20.4% ± 1.3%，静息时 SR -1.1 ± 0.15/秒（心率，79.4 ± 12.0 次/分钟），增加至 -22.6% ± 1.6% 和 -1.5 ± 0.16/秒低压力水平（心率，117.1 ± 8.7 次/分钟）和 -23.7% ± 1.1% 和 -1.9 ± 0.29/秒在次最大压力水平（心率，154.2 ± 7.0 次/分钟）下，分别回到 -20.6 % ± 1.4% 和 -1.2 ± 0.16/sec 运动后（心率，90.1 ± 9.4 次/分钟）。对次最大应力水平的限制确保了二维 STE 应变分析的足够图像质量。即使在次最大压力下，观察者间的应变变异性也是可以接受的。

结论

本研究为青少年和年轻人半仰卧自行车运动测试期间的 2D LV STE 衍生应变和 SR 提供​​了系统、标准化的协议和相应的参考数据。根据我们的结果，全局纵向应变和 SR 似乎是横断面研究中最容易理解的参数。