Left Atrial Distensibility and Left Ventricular Filling Pressure in Acute Myocardial Infarction

Left atrial volume (LAV) provides the significant prognostic information in the general population and patients with heart disease, including acute myocardial infarction, left ventricular dysfunction, mitral regurgitation, cardiomyopathy and atrial fibrillation. Large left atrial volume, which represents chronic diastolic dysfunction, is associated with poor outcome, regardless of systolic function. Thereby, LAV provides a long-term view of whether or not the patient has the disease of diastolic dysfunction, regardless of whatever loading conditions are present at the time of the examination, as the hemoglobin A1C in diabetes. However, whether left atrial (LA) parameters could correlate with LVFP and reflect short-term change in left ventricular filling pressure(LVFP) remains unknown. Only one article of our team confirmed the relationship between LAV and LVFP in patients with severe mitral regurgitation by simultaneous echocardiography-catheterization. The prior report proposed a new parameter, LA distensibility, and disclosed its logarithmic relationship with LVFP. The LA distensibility precisely indicated rapid change in LVFP of patients with acute severe mitral regurgitation, and was even superior to mitral E/Em (early-diastolic mitral inflow velocity divided by early-diastolic mitral annular velocity). As left atrial pressure rises to maintain adequate left ventricular diastolic filling, increased atrial wall tension tends to dilate the chamber and stretch the atrial myocardium. Therefore, the smaller left atrial stretchability, the more pressure left atrium (LA) faces to. The first objective of this study was to test the value of LA distensibility for assessing LVFP, particularly in patients with acute myocardial infarction. The second objective was to assess the prognostic value of LA distensibility.