Pozzoli M, Selva A, Skouse D, Traversi E, Mancini R, Bana G, Rossi A, Bossi M
Department of Cardiology, A. Manzoni Hospital, Lecco, Italy.
Eur J Echocardiogr. 2002 Mar;3(1):13-23. doi: 10.1053/euje.2001.0117.
Low flow velocity within the left atrial appendage, as assessed by transoesophageal echocardiography, is a predictor of thromboembolism and of a low success rate of cardioversion of atrial fibrillation. However, the semi-invasive nature does limit its serial application as a screening technique.
We investigated the value of transthoracic second harmonic echocardiography and pulsed Doppler at baseline and after intravenous contrast injection to visualize the left atrial appendage and assess blood flow velocities within its cavity. We studied 51 consecutive patients undergoing transoesophageal echocardiography. After transoesophageal echocardiography, transthoracic second harmonic imaging was performed and the left atrial appendage was visualized in 46 patients. Interpretable pulsed Doppler tracings of left atrial appendage flow were obtained at baseline in 39 patients and in 45 patients during Levovist administration. The correlations between peak emptying velocity of left atrial appendage as measured by transoesophageal echocardiography and by transthoracic standard and contrast-enhanced Doppler were 0.81 and 0.91, respectively. The agreement between transoesophageal echocardiography and transthoracic contrast-enhanced pulsed Doppler echocardiography in classifying left atrial appendage flow velocity patterns was 93%. Left atrial appendage thrombus was detected by transthoracic second harmonic imaging in only one of the eight patients shown by transoesophageal echocardiography to have a thrombus. However, all but one of the patients with left atrial appendage thrombus and/or spontaneous echocardiographic contrast at transoesophageal echocardiography had <30cm/s left atrial appendage flow velocity by transthoracic Doppler.
This study shows that left atrial appendage can be visualized by transthoracic second harmonic imaging and that the flow velocity within its cavity is reliably measured by pulsed Doppler in a substantial fraction of patients. Contrast enhancement improves the feasibility and the accuracy of transthoracic evaluation of left atrial appendage flow velocity. The practical value of these results in predicting thromboembolic risk and success of cardioversion of atrial fibrillation needs to be proved by prospective studies.
经食管超声心动图评估显示，左心耳内血流速度较低是血栓栓塞及房颤转复成功率低的一个预测指标。然而，其半侵入性本质确实限制了它作为一种筛查技术的连续应用。
我们研究了经胸二次谐波超声心动图及脉冲多普勒在基线状态及静脉注射造影剂后对左心耳的显影情况以及评估其腔内血流速度的价值。我们对51例连续接受经食管超声心动图检查的患者进行了研究。经食管超声心动图检查后，进行经胸二次谐波成像，46例患者的左心耳得以显影。39例患者在基线状态下以及45例患者在注射声诺维期间获得了可解读的左心耳血流脉冲多普勒描记图。经食管超声心动图测量的左心耳排空峰值速度与经胸标准及造影剂增强多普勒测量的左心耳排空峰值速度之间的相关性分别为0.81和0.91。经食管超声心动图与经胸造影剂增强脉冲多普勒超声心动图在左心耳血流速度模式分类方面的一致性为93%。经胸二次谐波成像仅在经食管超声心动图显示有血栓的8例患者中的1例检测到左心耳血栓。然而，经食管超声心动图显示有左心耳血栓和/或自发超声造影的患者中，除1例之外，其余所有患者经胸多普勒测量的左心耳血流速度均<30cm/s。
本研究表明，经胸二次谐波成像可显示左心耳，并且在相当一部分患者中，脉冲多普勒能够可靠地测量其腔内血流速度。造影剂增强提高了经胸评估左心耳血流速度的可行性和准确性。这些结果在预测血栓栓塞风险及房颤转复成功率方面的实际价值需要通过前瞻性研究来证实。
