Left atrial appendage Doppler flow patterns: Implications on thrombus formation The characteristics and clinical implications of left atrial appendage (LAA) flow have not been clearly analyzed. Thirty-nine consecutive patients underwent a transesophageal echocardiographic (TEE) color Doppler study to correlate the LAA pulsed Doppler flow pattern with echocardiographic variables and the cardiac rhythm of each patient. Three different LAA flow patterns were identified. Type I flow, characterized by a biphasic pattern (waves of filling and emptying), was found in 17 patients, all in sinus rhythm; it was not associated with LAA spontaneous contrast or thrombus. Mean peak velocities of the filling and emptying waves were, respectively: 28 + 12 cmlsec and 31 f 9 cmlsec. Type II sawtooth active flow (eight patients) (mean peak velocity: 49 f 12 cmlsec) was only detected in atrial fibrillation (AF) and dilated LAA (LAA area: 421 ? 40 mm*) but without thrombus or significant LAA spontaneous echocardiographic contrast. Type ill flow pattern was noted in 14 patients with AF and a very dilated LAA (LAA area: 619 5 96 mm*). This flow pattern was characterized by the absence of identifiable flow waves and was associated with the presence of LAA spontaneous contrast; the majority (six of seven) had evidence of thrombus. We concluded that the LAA is a dynamic structure in which TEE study identified three flow patterns with different implications. AF is associated with two LAA flow types (II and Ill) with a larger LAA size as well as a higher incidence of LAA clots in type Ill flow. (AM HEART J 1992;124:955.)

Miguel A. Garcia-FernBndez, MD, Esteban G. Torrecilla, MD, Daniel San RomLn, MD, Jo& Azevedo, MD, Hector Bueno, MD, M. Mar Moreno, MD, and Juan Luis Del&m, MD Madrid, Spain

Two-dimensional echocardiography is a well-established technique in the assessmentof left atria1 anatomy and in the diagnosis of left atria1 masses.However, the left atria1 appendage (LAA) is the only cardiac structure that remains difficult to examine thoroughly by the precordial approach.lj 2 However, transesophageal echocardiography (TEE) provides highly accurate images of the left atrium and particularly of the LAA.3-7 This technique is currently used for the assessmentof left atria1 spontaneous echocardiographic contrast and LAA thrombi and their relationship, together with the clinical outcome.4-11The predilection of the LAA for thrombus development is well known. However, the characteristics and possible clinical implications of LAA flow still remain to be clearly analyzed. Our study was directed at as-

From the Cardiology General “Gregorio Received

Department, Marafik”

for publication

Reprint requests: Miguel ment, Echocardiographic kk,” c/o Doctor Esquerdo, 4/113945’i


Echocardiographic 30, 1991;


A. Garcia-Fernkdez, Laboratory, Hospital 46. 28007 Madrid,

Laboratory, April


23. 1992.

MD, Cardiology General “Gregorio Spain.


sessing by means of TEE the characteristics of the dynamic flow of the LAA and its possible relationship to left atria1 dimensions and the presence of left atria1 and LAA spontaneous contrast and clots, as well as determining the cardiac rhythm of the patient. METHODS The study group consistedof 39 consecutivepatients (11 men and 28 women; mean age 56 + 23 years) who underwent a TEE study in our laboratory. At the study, 18 patients were in sinus rhythm, whereas the remaining 21 patients showed atria1 fibrillation. The reasons for the study were: the assessment of rheumatic valve disease (27 of 39; 69 ‘Y ); the evaluation of prostheses (4 of 39; 10 % ); the determination of mitral valve prolapse (2 of 39; 5%) and cardiomyopathy (2 of 39; 2.6%); and the investigation of the embolic source (4 of 39; 13 % ). Before the transesophageal evaluation, all patients underwent a complete transthoracic study (two-dimensional, spectral pulsed- and continuous-wave Doppler, and color flow Doppler studies) using a commercially available Doppler echocardiography unit (Sonos 1000, Hewlett-Packard Co., Medical Products Group, Andover, Mass.) with a 3.5 MHz phased-array transducer. Transthoracic two-dimensional echocardiographic examinations were performed following conventional criteria. Left atria1 area was measured by planime955



et al.

October 1992 Americ :a” Heart Journal

Fig. 1. Type I LAA Doppler flow pattern with well-defined emptying and filling waves (arrows in the UPper figure). The sample volume is placed in a small LAA cavity. The color-coded study across the 1,AA demonstrates the corresponding red emptying and blue filling Doppler flow farrows in the lower par ael).

try 0 f the endocardial borders of this structure as obtained the apical four-chamber view. SU lbsequently the TEE study was performed in each patient ; after topical anesthesia of the hypopharynx and mild subli ingual sedation with diazepam (10 mg). All studies were carried out by two experienced cardiologists using a 5.0 A4Hz transducer mounted at the end of a 100 cm echo-

scope. The echoscope was advanced 25 to 30 c‘rn from the incisors, and superior tilting of the tip of the ec:hoscope allowed consistent imaging of the left atria1 app sendage at a basal short-axis view.3 The total area of the LA ,A was measured with a trackball by tracing the endocarc Sal borders of this triangular extension of the left atria1 cat rity, and the area was calculated by computed planimetry. I n each case,

Volume Number

124 4

LA appendage

Fig. 2. Type II LAA flow pattern with an active “sawtooth” color-co ded study across the LAA shows the corresponding flow (ar rows in the lower panel).

was included in the the m maximum LAA area obtained analys ris. In the ! patients who were in sinus rhythm, the maxin mm LAA area at the onset of the P wave was mea(AF), this maxsured. In the pl ttients in atria1 fibrillation independently of the electroimum area was determined cardic tgram. Th e perimeters of the LAA extended from the apex t;o the has e of the limbus between the upper left pul-


flow patterns


flow profile (arrows in the upper figure). The bright red emptying and blue filling Doppler

monary vein and the LAA and a perpendicular straighi ; line drawn to the aorta. Clots were defined as echo-d ense masses within the LAA. Special care was taken in diffe !rentiating LAA clots from muscular ridges (pectinate Inuscles). Spontaneous dynamic contrast was defined as; the presence of swirling smoke-like echoes within the left atrium or the LAA, using appropriate gain settings. Fin LdlY,



et al.


October 1992 Heart Journal

Fig. 3. Type III LAA Doppler flow pattern with a very low profile. The sample volume is placed in the LAA. Note the enlarged LAA cavity associated with this Doppler flow pattern. One can observe the presence of discrete sharp signals during the inscription of QRS deflections, corresponding to wall noise artifacts. No LAA color-coded flow was registered. LA, Left atrium; SV, sample volume; AO, aortic root. pulsed-wave and color Doppler studies of the LAA flow were obtained in every patient. The sample volume was placed within the LAA body near the base of this structure and equidistant from both LAA walls. In each case we measured peak velocity and the area enclosed in the spectral tracing of the LAA filling and emptying Doppler waves. The values of three and five measurements were averaged in patients with sinus rhythm and AF, respectively. All studies were reviewed independently by two experienced observers with respect to the type of LAA flow and the presence of LAA clots and atria1 spontaneous contrast; any discrepancy was resolved by consensus. Statistical analysis. Values are reported as means t 1 SD. Chi-square tests were used to compare categorical variables. One-way analysis of variance was used to compare continuous variables between groups, with a subsequent Scheffe test for multiple means comparisons. Statis tical significance was defined as a two-tailed p < 0.05.


Three different flow patterns were identified within the LAA. Type I flow was characterized by a biphasic flow of clearly defined waves of filling and emptying (Fig. 1). On the other hand, in type II flow a characteristic “sawtooth” morphology of fast, well-defined flow waves was noted (Fig. 2), whereas in type III flow there were no identifiable flow waves in the LAA by Doppler testing (Fig. 3). Type I flow was present in 17 (43 9%) patients and all of them showed sinus rhythm. The prevalence of the different etiologies was: rheumatic mitral disease (eight patients); mitral prosthesis (two patients); mitral valve prolapse (two patients); dilated cardiomyopathy (one patient); finally four patients were studied for detection of cardiac source of embolism.

Volume Number

124 4

LA appendage

Doppler flow patterns


Table I. Cardiac rhythm and electrocardiographic data of the patients according to LAA flow pattern LAA I Patients


Atria1 fibrillation LA spontaneous LAA spontaneous LAA thrombus LA area (cm”) LAA area (cm*) LA, Left


17 contrast contrast

LAA, left atria1

O/17 3117 2117 l/17 20.1 + 5.2 3.3 zk 6.4










a/a 518

13/14 12114

Left atrial appendage Doppler flow patterns: implications on thrombus formation.

The characteristics and clinical implications of left atrial appendage (LAA) flow have not been clearly analyzed. Thirty-nine consecutive patients und...
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