The Relationship of Left Atrial Volume and Left Atrial Pressure in Patients With Hypertrophic Cardiomyopathy: An Echocardiographic and Cardiac Catheterization Study

Background: Left atrial enlargement is a marker of diastolic dysfunction, which is present in most patients with hypertrophic cardiomyopathy (HCM). It is unclear as to whether left atrial volume is a reliable measure of ventricular filling pressures in these patients. Methods: Left atrial volume index (LAVI) was measured in 100 symptomatic patients with HCM using transthoracic echocardiography, followed by cardiac catheterization with transseptal measurement of left atrial pressure (LAP) and end-diastolic pressure within 48 hours. Results: LAVI was only modestly related to mean LAP (r = 0.24, P = .02), and there was no significant relation to end-diastolic pressure (r = 0.11, P = .28). The specificity of increased LAVI (>28 cm(3)/m(2)) for elevated LAP (>15 mm Hg) was poor (16%). However, all patients with normal LAVI had normal LAP. Conclusions: Although left atrial size may reflect chronic changes due to diastolic dysfunction in HCM, the relation of increased LAVI to ventricular filling pressures is modest. Nonetheless, a normal LAVI suggests normal ventricular filling pressures in patients with HCM. (J Am Soc Echocardiogr 2009; 22: 961-6.)