Application of retrograde non-transseptal catheterization in the study of left atrial mechanics

The study of the pressure-dimension relationship is a valuable tool for dec iphering the function of cardiac chambers in health and disease. Acquisitio n of accurate measurements of left atrial pressure to use subsequently in a rriving at the left atrial pressure-dimension relationship, has been restri cted by the need to perform transseptal left heart catheterization. In our institution, we have developed a new approach for invasive acquisition of p recise left atrial pressure measurements by employing an externally steerab le left atrial guiding catheter to introduce a Millar micromanometer into t he left atrium retrogradely, via the left ventricle. To produce the left at rial pressure-area relationship, left atrial pressure measurements obtained by this technique were combined with simultaneous measurements of instanta neous left atrial area derived by automatic boundary detection real-time tw o-dimensional transthoracic echocardiography. This methodology has proved s afe and efficient and was applied in the study of left atrial mechanics in response to inotropic stimulation as well as in relation to the performance of retrograde non-transseptal balloon mitral valvuloplasty in patients wit h mitral stenosis. The technique of retrograde non-transseptal left atrial catheterization for left atrial pressure measurement is described in detail and the results of studies of left atrial function conducted thus far are briefly reviewed.