Jung Mi-Hyang, Jung Hae Ok, Lee Jung-Won, Youn Ho-Joong
Division of Cardiology, Department of Internal Medicine, College of Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
Echocardiography. 2017 Nov;34(11):1633-1639. doi: 10.1111/echo.13666. Epub 2017 Aug 22.
Doppler-driven net atrioventricular compliance (C ), which represents left atrial (LA) compliance, is an important determinant of pulmonary hypertension in mitral stenosis (MS).
We hypothesized that decreases in C during early-stage exercise underlie exercise intolerance in patients with MS.
Thirty-three asymptomatic patients with significant MS (valve area 1.24 ± 0.16 cm ) underwent resting and bicycle exercise echocardiography. LA compliance and conventional parameters were assessed at each workload. The patients were classified into two groups based on whether they developed dyspnea during exercise: an exercise-intolerance group (n = 22) and an exercise-tolerance group (n = 11). Moreover, "50 W" was defined as an early exercise stage.
Although the groups had similar resting characteristics, there were striking differences in their echocardiographic parameters from the early stages of exercise. The relative C decrease at 50 W (expressed as a percentage of the resting C ) was significantly greater in the exercise-intolerance group (70.3 ± 15.4% vs 49.7 ± 9.7%, P < .001). The overall decrease in relative C was significantly greater in the exercise-intolerance group (P = .0005). Furthermore, differences in the trends in this parameter were observed between the two groups (P < .0001 for interaction). Multivariate analysis revealed that the relative C decrease at 50 W was an independent predictor of exercise intolerance (adjusted OR 1.105, 95% CI 1.030-1.184) after adjustment for other conventional parameters.
Decreases in C during early-stage exercise are an important mechanism underlying exercise intolerance in MS.
由多普勒驱动的房室净顺应性（C）代表左心房（LA）顺应性，是二尖瓣狭窄（MS）患者肺动脉高压的重要决定因素。
我们假设MS患者在早期运动期间C的降低是运动不耐受的基础。
33例无症状的重度MS患者（瓣口面积1.24±0.16cm²）接受静息和踏车运动超声心动图检查。在每个工作量下评估LA顺应性和传统参数。根据患者在运动期间是否出现呼吸困难将其分为两组：运动不耐受组（n = 22）和运动耐受组（n = 11）。此外，“50W”被定义为早期运动阶段。
尽管两组具有相似的静息特征，但在运动早期其超声心动图参数存在显著差异。运动不耐受组在50W时相对C的降低（以静息C的百分比表示）显著更大（70.3±15.4%对49.7±9.7%，P <.001）。运动不耐受组相对C的总体降低显著更大（P =.0005）。此外，两组之间观察到该参数趋势的差异（交互作用P <.0001）。多变量分析显示，在调整其他传统参数后，50W时相对C的降低是运动不耐受的独立预测因素（调整后的OR 1.105，95%CI 1.030 - 1.184）。
MS患者在早期运动期间C的降低是运动不耐受的重要机制。
