Background: Diastolic dysfunction is a major pathophysiological abnormality in hypertrophic cardiomyopathy (HCM). Doppler echocardiographic parameters correlate with left ventricular (LV) filling pressures in other diseases, but it is unclear whether these findings apply to patients with HCM, who have multiple complex interrelated events leading to diastolic dysfunction. This study compares Doppler echocardiographic estimates of filling pressures to direct measurements of left atrial pressure (LAP) via catheterization in 100 patients with HCM.
Methods and results: One hundred patients who were symptomatic with HCM (New York Heart Association class III/IV, 82%) underwent measurement of early diastolic transmitral flow velocity (E) and mitral annular velocities (e') with the use of transthoracic echocardiography within 48 hours of cardiac catheterization with direct measurement of LAP. In a subset of 42 patients, echocardiographic and catheterization measurements were performed simultaneously. Mean LAP directly correlated with medial E-e' ratio in the overall population (r=0.44, P<0.0001) and also in the subgroup of patients who had simultaneous echocardiographic and catheterization studies (r=0.28, P=0.07). However, scatter was present. A calculated mean LV filling pressure was derived from the E-e' ratio with the use of a previously described regression equation, and the 95% confidence limits of agreement with measured mean LAP exceeded +/-18 mm Hg both for the overall group and for the subgroup who had simultaneous studies. Similar results were obtained with the lateral E-e' ratio. Only 1 patient had a previously defined "normal" E-e' ratio of <8.
Conclusions: In symptomatic patients with HCM, Doppler echocardiographic estimates of LV filling pressure with the use of transmitral flows and mitral annular velocities correlate modestly with direct measurement of LAP. Given the complex nature of diastolic dysfunction in HCM, precise characterization of LV filling pressure in an individual patient cannot be determined with the use of these noninvasive parameters.