Three dimensional flow in the human left atrium

• Published in: Heart (British Cardiac Society) Vol. 86; no. 4; pp. 448 - 455
• Main Authors: Fyrenius, A, Wigström, L, Ebbers, T, Karlsson, M, Engvall, J, Bolger, A F
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd and British Cardiovascular Society 01.10.2001; BMJ; BMJ Publishing Group Ltd; BMJ Publishing Group LTD
• Subjects: Adult; Atrial fibrillation; Atrial Function; Atrial Function, Left - physiology; atrium; Basic Research; Biological and medical sciences; Blood clot; blood flow; Blood Flow Velocity - physiology; Cardiovascular system; Diastole - physiology; Embolism; Female; haemodynamics; Heart; Heart ventricle, Left; Humans; Investigative techniques, diagnostic techniques (general aspects); Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Male; Medical sciences; MEDICIN; MEDICINE; Middle Aged; Mitral valve stenosis; Pulmonary Veins - physiology; Radiodiagnosis. Nmr imagery. Nmr spectrometry; Risk factors; Systole - physiology; Thrombosis; Veins & arteries; Velocity; Vortices; United States; United States > US; Heart; Human; Medical imagery; Exploration; Tridimensional image; Circulatory system; Hemodynamics; Left atrium; Technique; Nuclear magnetic resonance imaging; Blood flow
• ISSN: 1355-6037; 1468-201X; 1468-201X
• DOI: 10.1136/heart.86.4.448

BACKGROUND Abnormal flow patterns in the left atrium in atrial fibrillation or mitral stenosis are associated with an increased risk of thrombosis and systemic embolisation; the characteristics of normal atrial flow that avoid stasis have not been well defined. OBJECTIVES To present a three dimensional particle trace visualisation of normal left atrial flow in vivo, constructed from flow velocities in three dimensional space. METHODS Particle trace visualisation of time resolved three dimensional magnetic resonance imaging velocity measurements was used to provide a display of intracardiac flow without the limitations of angle sensitivity or restriction to imaging planes. Global flow patterns of the left atrium were studied in 11 healthy volunteers. RESULTS In all subjects vortical flow was observed in the atrium during systole and diastolic diastasis (mean (SD) duration of systolic vortex, 280 (77) ms; and of diastolic vortex, 256 (118) ms). The volume incorporated and recirculated within the vortices originated predominantly from the left pulmonary veins. Inflow from the right veins passed along the vortex periphery, constrained between the vortex and the atrial wall. CONCLUSIONS Global left atrial flow in the normal human heart comprises consistent patterns specific to the phase of the cardiac cycle. Separate paths of left and right pulmonary venous inflow and vortex formation may have beneficial effects in avoiding left atrial stasis in the normal subject in sinus rhythm.