Division of Cardiovascular Diseases, Mayo Clinic, Scottsdale, Arizona, USA.
JACC Cardiovasc Imaging. 2010 Jan;3(1):1-9. doi: 10.1016/j.jcmg.2009.08.011.
We explored the incremental value of quantification of tissue Doppler (TD) velocity during the brief isovolumic contraction (IVC) phase of the cardiac cycle for the prediction of exercise performance in patients referred for cardiopulmonary exercise testing (CPET).
Experimental studies have shown that rapid left ventricular (LV) shape change during IVC is essential for optimal onset of LV ejection. However, the incremental value of measuring IVC velocities in clinical settings remains unclear.
A total of 82 subjects (age 53+/-14 years, 56 men) were studied with echocardiography and CPET. Reduced LV ejection fraction (EF) (EF<50%) was present in 38 (46%) subjects. Pulsed-wave annular TD velocities were averaged from the LV lateral and septal annulus during isovolumic contraction (IVCa), ejection, isovolumic relaxation, and early and late diastole (Aa) and compared with peak oxygen consumption (VO2) and percentage of the predicted peak VO2 (% predicted peak VO2) obtained from CPET.
Patients with reduced EF had lower IVCa (6.3 vs. 4.5 cm/s, p=0.04), ejection (7.7 vs. 5.5 cm/s, p<0.001), and Aa velocities (7.9 vs. 6.6 cm/s, p=0.04). Similarly, % predicted peak VO2 was lower in patients with reduced EF (52.9% vs. 73.1%, p<0.001) and correlated with the variations in IVCa (r=0.7, p=0.001). Multivariate analysis of 2-dimensional and Doppler variables in the presence of reduced LV EF revealed only IVCa and Aa as independent predictors of % predicted peak VO2 (r2=0.612, p=0.02 for IVCa and p=0.009 for Aa). The overall performance of IVCa in the prediction of exercise capacity was good (area under the curve=0.86, p<0.001).
Assessment of TD-derived IVC and atrial stretch velocities provide independent prediction of exercise capacity in patients with reduced LV EF. Assessment of LV pre-ejectional stretch and shortening mechanics at rest may be useful for determining the myocardial functional reserve of patients with reduced EF.
我们探讨了在心动周期的短暂等容收缩（IVC）阶段测量组织多普勒（TD）速度的增量值对于预测因心肺运动测试（CPET）而就诊的患者的运动表现的作用。
实验研究表明，IVC 期间左心室（LV）快速变形对于 LV 射血的最佳起始至关重要。然而，在临床环境中测量 IVC 速度的增量价值仍不清楚。
对 82 名患者（年龄 53+/-14 岁，56 名男性）进行超声心动图和 CPET 检查。38 名（46%）患者存在左室射血分数降低（EF<50%）。在等容收缩（IVCa）、射血、等容舒张以及早期和晚期舒张（Aa）期间，从 LV 侧壁和间隔环获得脉冲波环形 TD 速度平均值，并与 CPET 获得的最大耗氧量（VO2）和最大 VO2 预测百分比（% predicted peak VO2）进行比较。
EF 降低的患者的 IVCa（6.3 与 4.5 cm/s，p=0.04）、射血（7.7 与 5.5 cm/s，p<0.001）和 Aa 速度（7.9 与 6.6 cm/s，p=0.04）较低。同样，EF 降低的患者的% predicted peak VO2 较低（52.9%与 73.1%，p<0.001），并且与 IVCa 的变化相关（r=0.7，p=0.001）。在 LV 射血分数降低的情况下，二维和多普勒变量的多元分析仅发现 IVCa 和 Aa 是% predicted peak VO2 的独立预测因素（IVCa 的 r2=0.612，p=0.02；Aa 的 p=0.009）。IVCa 在预测运动能力方面的整体性能良好（曲线下面积=0.86，p<0.001）。
TD 衍生的 IVC 和心房牵张速度评估可独立预测 LV 射血分数降低的患者的运动能力。在休息时评估 LV 射血前的牵张和缩短力学可能有助于确定 EF 降低患者的心肌功能储备。
