Left atrial remodelling in mitral regurgitation-methodologic approach, physiological determinants, and outcome implications: a prospective quantitative Doppler-echocardiographic and electron beam-computed tomographic study

• Published in: European heart journal Vol. 28; no. 14; pp. 1773 - 1781
• Main Authors: Messika-Zeitoun, David, Bellamy, Michael, Avierinos, Jean-Francois, Breen, Jerome, Eusemann, Christian, Rossi, Andrea, Behrenbeck, Thomas, Scott, Christopher, Tajik, Jamil A., Enriquez-Sarano, Maurice
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.07.2007; Oxford Publishing Limited (England)
• Subjects: Aged; Atrial Function, Left - physiology; Biological and medical sciences; Blood Flow Velocity - physiology; Cardiology. Vascular system; Cardiovascular system; Cohort Studies; Electrocardiography - methods; Endocardial and cardiac valvular diseases; Female; Heart; Heart Atria - ultrastructure; Humans; Investigative techniques, diagnostic techniques (general aspects); Male; Medical sciences; Middle Aged; Mitral Valve Insufficiency - diagnostic imaging; Prospective Studies; Tomography, Emission-Computed - methods; Ultrasonic investigative techniques; Ultrasonography; Atrium; Mitral valve; Echocardiography; Computed tomography; Outcome; Sonography; Prognosis; Radiodiagnosis; Determinant; Electron beam; Cardiovascular disease; Left atrium; Phlebology; Prospective; Cardiac valvular disease; Mitral regurgitation; Medical imagery; Evolution; Computerized axial tomography; Circulatory system; Cardiology; Quantitative analysis
• ISSN: 0195-668X; 1522-9645
• DOI: 10.1093/eurheartj/ehm199

Aims To define accurate and normal range of echocardiographic left atrial (LA) volume measurement and to assess the prevalence, determinants, and outcome implications of LA enlargement in mitral regurgitation (MR). Methods and results We prospectively compared LA volume obtained simultaneously by electron beam-computed tomography (EBCT) and by four echocardiographic methods in 33 test patients. Accurate echocardiographic LA volume measurements were obtained only by biplane area-length method with vertical longitudinal-length (r = 0.95, P < 0.0001; 145 ± 57 vs. 143 ± 55 mL, P = 0.57). Using this method, the normal range in 100 normal subjects, the physiological determinants and outcome implications of LA enlargement in 320 patients with organic MR were analysed. In normal subjects, indexed to body surface area, LA index (27 ± 6 mL/m2) was not influenced by age or gender and values ≥ 40 mL/m2 were beyond the upper limit of normal. In MR, the most powerful determinants of LA enlargement were higher regurgitant volume (RVol) and atrial fibrillation (AF) (P < 0.0001), followed by older age, female gender, higher left ventricular end-systolic volume, and mass (all P < 0.001). After diagnosis in sinus rhythm, LA index ≥ 40 mL/m2 predicted superiorly and independently to LA diameter the occurrence of AF [adjusted RR 1.48 (1.06-2.16), P < 0.01] and the combined endpoint of death or need for mitral surgery [adjusted RR 1.61 (1.3-2.0), P < 0.0001]. Conclusion LA remodelling can be accurately assessed by echocardiography and LA index ≥ 40 mL/m2 is beyond the normal range. In organic MR, higher LA index is the combined result of multiple physiological effects, provides independent prognostic information, and therefore should be part of a comprehensive echocardiographic examination.