Waggoner A D, Barzilai B, Miller J G, Pérez J E
Cardiovascular Division, Washington University, St Louis, MO 63110.
Circulation. 1993 Sep;88(3):1142-9. doi: 10.1161/01.cir.88.3.1142.
Direct assessment of left atrial (LA) function has not been previously performed by noninvasive techniques; rather, LA function has been evaluated only indirectly via the analysis of transmitral flow velocity by Doppler. The recent development of real-time two-dimensional echocardiographic automatic boundary detection suggests that LA dimensions can be measured instantaneously to provide on-line assessment of its systolic and diastolic functions.
We performed echocardiographic assessment of LA dimensions and function with automatic boundary detection in 45 patients by using the apical four-chamber view. Thirty-seven patients had structural or functional cardiac abnormalities, 35 patients were in sinus rhythm, and 10 patients had atrial fibrillation. Moderate to severe mitral regurgitation (MR) was noted in 16 patients. We also studied 10 control subjects to assess normal values of LA cavity area and indexes of function. From the instantaneously derived LA area, we derived indexes of systolic atrial expansion and diastolic atrial emptying. There were excellent correlations between the on-line-derived LA areas and those measured off line from videotaped images of conventional echocardiography (r = .91 for end-diastolic and .93 for end-systolic areas; SEE, 4.0 and 3.8 cm2, respectively). Patients in atrial fibrillation had depressed diastolic emptying index (0.17 +/- 0.05) compared with those in sinus rhythm (0.28 +/- 0.12; P < .02). Furthermore, patients with chronic MR exhibited larger LA cavity areas and depressed systolic and diastolic LA function as compared with those without MR. In addition, the Doppler-determined mitral E/A ratio was related to the ratio of early diastolic-to-late diastolic change in LA cavity area (r = .79; SEE 0.6; n = 35).
Instantaneous LA cavity area measurement by echocardiographic automatic boundary detection is accurate and feasible in patients with diverse cardiac disorders. Patients with atrial fibrillation had a depressed diastolic emptying index and those with significant mitral regurgitation had depressed systolic expansion index as well. LA functional indexes in both systole and diastole can be derived providing an approach for quantitative evaluations of left atrial-left ventricular interactions based on geometric assessment noninvasively.
以往非侵入性技术尚未对左心房（LA）功能进行直接评估；相反，LA功能仅通过多普勒分析二尖瓣血流速度进行间接评估。实时二维超声心动图自动边界检测技术的最新发展表明，可以即时测量LA尺寸，以在线评估其收缩和舒张功能。
我们通过心尖四腔视图，采用自动边界检测对45例患者进行了LA尺寸和功能的超声心动图评估。37例患者存在心脏结构或功能异常，35例患者为窦性心律，10例患者为心房颤动。16例患者存在中度至重度二尖瓣反流（MR）。我们还研究了10名对照受试者，以评估LA腔面积和功能指标的正常值。从即时得出的LA面积，我们得出了收缩期心房扩张和舒张期心房排空的指标。在线得出的LA面积与从传统超声心动图录像图像离线测量的面积之间存在极好的相关性（舒张末期面积r = 0.91，收缩末期面积r = 0.93；标准误分别为4.0和3.8 cm²）。与窦性心律患者（0.28±0.12）相比，心房颤动患者的舒张期排空指数降低（0.17±0.05；P < 0.02）。此外，与无MR的患者相比，慢性MR患者的LA腔面积更大，LA收缩和舒张功能降低。此外，多普勒测定的二尖瓣E/A比值与LA腔面积舒张早期与舒张晚期变化的比值相关（r = 0.79；标准误0.6；n = 35）。
通过超声心动图自动边界检测即时测量LA腔面积在各种心脏疾病患者中准确可行。心房颤动患者的舒张期排空指数降低，严重二尖瓣反流患者的收缩期扩张指数也降低。可以得出LA收缩期和舒张期的功能指标，为基于几何评估无创定量评估左心房-左心室相互作用提供了一种方法。
