The Influence of Atrial Size and Elasticity on the Left Atrial Pressure Tracing

There has been much argument for and against the value of the left atrial pressure tracing in the assessment of mitral stenosis and regurgitation Attention was first directed to the height and shape of the V wave (Lagerlof and Werko, 1949; Gorlin et al., 1952; Eliasch, 1952; Biorck et al., 1953; Logan and Turner, 1953; Connolly et al., 1955) and later to the diastolic y descent expressed as the Ry/V ratio (Owen and Wood, 1955). While the use of the y descent generally provides a good guide to the type of mitral valve lesion present, an occasional case of dominant mitral regurgi-tation has a small V wave and an Ry/V ratio within the stenotic range (less than 1.7). The use of a pressure tracing to differentiate between mitral stenosis and regurgitation involves the assumption that a given change in the left atrial volume will, in different patients, result in the same change in left atrial pressure. However, two other factors beside the change in volume influence the pressure changes, namely the size of the left atrium and the elastic properties of its walls. An attempt has been made to assess the influence of these factors on the indirect left atrial pressure tracing and to review the value of the Ry/V ratio in the light of these findings. MATERIAL AND METHODS The Ry/V ratio (Owen and Wood, 1955) was estimated in eighty patients in whom a clinical