JCM/200426; Total nos of Pages: 6; Transthoracic Doppler echocardiography for the assessment of left atrial appendage size and blood flow velocity. A multicentre study Claudio Coletta a , Tommaso Infusino b , Sebastiano Sciarretta b , Augusto Sestili a , Paolo Trambaiolo c , Cinzia Cianfrocca d , Elettra De Marchis a , Antonio Auriti d and Alessandro Salustri c Objective The aim of this study was to evaluate the reliability of transthoracic Doppler echocardiography (TTE) in the assessment of left atrial appendage (LAA) size and function. Methods We considered 86 consecutive patients (56 male, 30 female; mean age 64 W 13 years, sinus rhythm 36 patients [42%]; atrial flutter/fibrillation 50 patients [58%]) referred for transoesophageal echocardiography (TEE) and TTE. Maximum LAA transverse diameters and LAA peak flow velocities were calculated by two-dimensional and pulsed-wave Doppler analysis at TEE and TTE. Results LAA systolic transverse diameters were detectable in 78 patients (91%) by TTE and showed a significant correlation with TEE (r U 0.77, P < 0.0001). LAA peak flow velocities were measurable by TTE in 72 patients (84%) and were comparable with TEE (50.4 W 23 vs 47.3 W 23.2 cm/s, r U 0.67, P < 0.0001). A peak blood flow velocity of <25 cm/s at TTE was the best indicator of very low (<20 cm/s) LAA flow velocity as detected by TEE (sensitivity 93%, specificity 87%, area under the curve 0.94, P < 0.0001). Conversely, a peak blood flow velocity of >56 cm/s at TTE indicated a very high (> 40 cm/s) LAA flow velocity as detected by TEE (sensitivity 50%, specificity 96%, area under the curve 0.87; P < 0.0001). Conclusions Reliable LAA size and blood flow velocities can be obtained by TTE in consecutive, unselected patients. TTE identifies patients with low and high blood flow velocities in the LAA, providing helpful information for the definition of individual embolic risk. J Cardiovasc Med 8:000–000 Q 2007 Italian Federation of Cardiology. Journal of Cardiovascular Medicine 2007, 8:000–000 Keywords: blood flow velocity, left atrial appendage, transoesophageal echocardiography, transthoracic echocardiography a Department of Cardiology, S. Spirito Hospital, Rome, Italy, b Department of Cardiology, S. Andrea Hospital, Second Faculty of Medicine, ‘La Sapienza’ University, Rome, Italy, c Department of Cardiology, P.O. Portuense, Rome, Italy and d Department of Cardiology, S. Filippo Hospital, Rome, Italy Correspondence to Dr Sebastiano Sciarretta, Department of Cardiology, S. Andrea Hospital, ‘La Sapienza’ University, Via di Grottarossa 1035, 00189 Rome, Italy Tel: +39 06 33775563; mobile: þ39 339 3229867; fax: +39 06 33775546; e-mail: sebastianosciarretta@yahoo.it Received 12 December 2006 Revised 30 January 2007 Accepted 1 February 2007 Introduction Transoesophageal Doppler echocardiography (TEE) is the gold standard technique for evaluating left atrial appendage (LAA) morphology and function. State-of- the-art multiplane transducers allow the study of its complex anatomy, with a bilobed and multilobed (>3 lobes) structure present in a high proportion of normal human autopsy hearts [1], and the detection of hidden thrombi [2]. As a consequence, TEE is suitable for the identification of the individual embolic risk in case of atrial fibrillation and need for cardioversion [3], but also for the research of embolic sources in patients with brain or peripheral ischaemic episodes [4]. The semi-invasive nature of this procedure determines a not negligible overall complication incidence [5] and unsatisfactory patient compliance, along with the need for informed consent and sedation. Furthermore, TEE requires skilled operators and the cost of the procedure is higher than conventional transthoracic Doppler echocardiography (TTE). This makes any alternative non-invasive approach potentially attractive for the assessment of LAA morphology and function. The aim of our study was to evaluate the feasibility and accuracy of TTE using tissue harmonic imaging in the assessment of LAA linear dimensions and blood flow velocities in unselected patients referred for TEE. Methods Population The investigation was planned as a multicentre, single- blind study involving three tertiary cardiology institu- tions in Rome, Italy. Between February and November Original article JCM 200426 1558-2027 ß 2007 Italian Federation of Cardiology