Asrar ul Haq Muhammad, Mutha Vivek, Lin Tina, Profitis Konstantinos, Tuer Zoe, Lim Kwang, Hare David L, Wong Chiew
Department of Cardiology, The Northern Hospital, 185 Cooper Street, Melbourne, Victoria 3076, Australia.
Cardiovasc Ultrasound. 2014 Feb 15;12:8. doi: 10.1186/1476-7120-12-8.
2D speckle tracking echocardiography allows for assessment of left ventricular (LV) torsional deformation as a composite function of the radial, longitudinal and circumferential fibres. We test the hypothesis that post-exercise LV torsional dynamics are more sensitive markers for myocardial dysfunction than resting measures, and better predictors for exercise capacity compared to post-exercise LV diastolic filling pressure (E/e').
We studied 88 patients referred for stress echocardiogram. Treadmill exercise was performed using Bruce protocol, and echo images were acquired using GE Vivid 7. LV rotational dynamics were analysed by speckle tracking method using the GE ECHOPAC software. Tertiles were defined according to exercise capacity measured by the achieved metabolic equivalents (METS) adjusted for age and gender. Comparison was made between LV torsional dynamics and E/e' to correlate with METS to predict exercise capacity.
Mean age of the study population was 58 years, 48% females. Patients with systolic dysfunction or evidence of ischaemia were excluded from the analysis. No significant correlation was found between METS and LV torsion measures at rest. There was statistically significant correlation between METS and post-exercise LV torsion (r=0.34, p=0.001), twist velocity increase (r=0.27, p=0.01), and incremental change in torsion (r=0.22, p<0.05). In addition, a correlation was also shown between post-exercise E/e' and METS (r=-0.33, p=0.002).
Post-exercise LV torsional dynamics correlate with exercise capacity and may be a useful tool for assessing LV myocardial function in subjects with normal LVEF.
二维斑点追踪超声心动图可用于评估左心室（LV）扭转变形，它是径向、纵向和圆周纤维的复合功能。我们检验了这样一个假设，即运动后左心室扭转动力学是比静息测量更敏感的心肌功能障碍标志物，并且与运动后左心室舒张期充盈压（E/e'）相比，是运动能力更好的预测指标。
我们研究了88例接受负荷超声心动图检查的患者。使用布鲁斯方案进行跑步机运动，并使用GE Vivid 7采集超声图像。使用GE ECHOPAC软件通过斑点追踪方法分析左心室旋转动力学。根据通过根据年龄和性别调整后的达到的代谢当量（METS）测量的运动能力定义三分位数。比较左心室扭转动力学和E/e'与METS的相关性，以预测运动能力。
研究人群的平均年龄为58岁，女性占48%。收缩功能障碍或有缺血证据的患者被排除在分析之外。静息时METS与左心室扭转测量之间未发现显著相关性。METS与运动后左心室扭转（r = 0.34，p = 0.001）、扭转速度增加（r = 0.27，p = 0.01）以及扭转增量变化（r = 0.22，p < 0.05）之间存在统计学显著相关性。此外，运动后E/e'与METS之间也显示出相关性（r = -0.33，p = 0.002）。
运动后左心室扭转动力学与运动能力相关，可能是评估左心室射血分数正常受试者左心室心肌功能的有用工具。
