title: Transthoracic Versus Transesophageal Two-Dimensional Echo Doppler Determination of Flow Velocity in the Left Atrial Appendage.
abstract: The assessment of flow velocity (FV) in the left atrial appendage (LAA) by transesophageal echocardiography (TEE) has been reported to be a useful tool as a high risk marker for systemic emboli. The analysis of FV in LAA by transthoracic echocardiography (TTE) has not yet been validated. The purpose of this study was to compare FV measurements in the LAA by TEE and TTE in 30 consecutive patients (age 19-87 years, mean = 55) sent for echocardiographic study with the following diagnosis: stroke (11 patients), mitral stenosis (6 patients), congenital heart disease (4 patients), mitral prosthetic function assessment (2 patients), and other pathologies (7 patients). FV was measured at the outlet and mid-portion of the LAA with TTE, from the apical two-chamber view and with biplane TEE, from the longitudinal two-chamber view. Satisfactory measurements were obtained with TTE from the outlet of the LAA in 96.7% and from the mid-portion of the LAA in 90% of patients. One third of patients were in atrial fibrillation (AF) during the study. The mean FV in the outlet of the LAA was 32.7 +/- 2.5 (SE) cm/sec with TTE and was 33.7 +/- 3.04 (SE) cm/sec with TEE (r = 0.95). The mean FV in the mid-portion of the LAA was 40.9 +/- 3.3 and 42.7 +/- 3.9 with TTE and TEE respectively (P = NS) (r = 0.95). There was no difference in the LAA FV determination by TTE and TEE in the subgroup with AF. TTE was able to detect FV < 30 cm/sec with a sensitivity of 88% and specificity of 81% and a positive predictive value of 84% compared with TEE.
authors.affiliation: Division of Cardiology, Chilean Air Force Hospital, Santiago, Chile.
authors.forename: César
authors.initials: C
authors.lastname: Carranza
authors.forename: Alejandro
authors.initials: A
authors.lastname: Abufhele
authors.forename: Fanny
authors.initials: F
authors.lastname: Cartes
authors.forename: Alejandro
authors.initials: A
authors.lastname: Forero