Background:

In severe aortic stenosis (AS), reduced left ventricular ejection fraction (LVEF) (<50%) may be attributed to decreased contractility, afterload mismatch (AM) or a combination of both mechanisms. However, when LVEF is ≥50% some patients may have decreased contractility.

Objective:

The aim of this study was to assess contractility level (CL), AM and ventricular geometry as determinants of LVEF in patients with severe AS.

Methods:

Doppler echocardiography was used to study 184 patients with severe AS and 71 normal individuals (N). Contractility was assessed as the difference between measured and predicted midwall fractional shortening (mFS) minus 2 standard errors for an established meridional end-systolic stress (ESS). Patients with AS were divided into 4 groups: LVEF <50% (n = 78), LVEF 50-59% (n = 27), LVEF 60-69% (n = 45), and LVEF ≥70% (n = 34).

Results:

Decreased CL was observed in approximately half of the patients with LVEF <60% and in a lesser degree in patients with LVEF ≥60%. Afterload mismatch was found in patients with LVEF <50% with decreased (34%) as well as preserved (45%) CL. Conclusions: Half of the patients with LVEF <60% presented decreased CL and to a lesser extent this occurred in the rest of the patients, even with LVEF ≥70%. The overestimation of systolic function using LVEF seems to be related to the degree of concentric hypertrophy..