title: Assessment of left atrial operative mean stiffness using simultaneous recordings of left ventricular pressure and M-mode echocardiography of the left atrium and mitral valve.
abstract: Left atrial (LA) operative mean stiffness was measured using simultaneous recordings of the left ventricular (LV) pressure and M-mode echocardiography of the LA and mitral valve. The LA operative passive mean stiffness value was obtained during LV systole using LV pressure at the mitral valve opening and the pre-atrial contraction where the LV and LA pressure curves cross each other. Before the LA stiffness measurement, the LA volume calculated by biplane left atriography was compared with the dimension of the LA M-mode echocardiogram at three points (maximum volume, pre-atrial contraction and minimum volume) in another 23 patients (5 normal subjects, 4 patients with angina pectoris, 14 patients with myocardial infarction), and the regression equation was obtained by power fitting (y = ax3+ b). Using this equation, the LA volumes were calculated and used for the measurement of LA operative mean stiffness. Eleven normal subjects (C group), 14 patients with myocardial infarction (ejection fraction: EF > or = 55%; NF group), and 12 patients with myocardial infarction (EF < 55%; F group) were studied. The measured operative mean stiffness values based on the LA dimension and LV pressure [K(D)] were 0.69 +/- 0.40, 1.0 +/- 0.37, and 2.0 +/- 0.61 mmHg/mm, respectively (p < 0.01 in C vs F). The mean stiffness values calculated with LA volume [K(V)] were 0.48 +/- 0.23, 0.42 +/- 0.19, and 0.66 +/- 0.25 mmHg/ml, respectively (p < 0.05 in NF vs F). In F group, both the K(D) and K(V) values were high. The K(D) value can thus be used clinically as an easily obtained index of the LA operative mean stiffness. The high LA operative mean stiffness in F group appeared to be related to the increased LA pressure at the mitral valve opening. This method of measurement of the LA operative mean stiffness can be easily applied and used as a routine measurement providing additional information regarding left ventricular function.
authors.affiliation: Second Department of Internal Medicine, Gifu University School of Medicine.
authors.forename: M
authors.initials: M
authors.lastname: Tomita
authors.forename: K
authors.initials: K
authors.lastname: Kagawa
authors.forename: T
authors.initials: T
authors.lastname: Noda
authors.forename: K
authors.initials: K
authors.lastname: Nishigaki
authors.forename: H
authors.initials: H
authors.lastname: Fujiwara
mesh_terms: D000368:Aged; D000787:Angina Pectoris / Q000000981:diagnostic imaging / Q000503:physiopathology; D006328:Cardiac Catheterization; D002306:Cardiac Volume; D004452:Echocardiography; D006325:Heart Atria / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008943:Mitral Valve / Q000000981:diagnostic imaging*; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000503:physiopathology; D016277:Ventricular Function, Left; D017725:Ventricular Pressure