ABSTRACT
BACKGROUND: Low-level exercise echocardiography is useful to assess left ventricular (LV) contractile reserve after an acute myocardial infarction. Whether low-level exercise can elicit LV contractile reserve in patients with severe aortic stenosis, reduced LV systolic function and low transvalvular gradient are unknown. Accordingly, the value of low-level exercise to elicit contractile reserve was assessed in these patients using dobutamine administration as the gold standard method. METHODS AND RESULTS: Seventeen patients with severely decreased aortic valve area (0.75 +/- 0.03 cm(2)), reduced LV ejection fraction (35 +/- 2%) and low mean transvalvular gradient (23 +/- 3 mmHg) underwent low-level exercise and dobutamine echocardiography. Ejection fraction increased by 23% (P < 0.001) with dobutamine and decreased by 8% (P = 0.2) with low-level exercise. Left ventricular outflow tract velocity time integral increased from 13 +/- 1 to 16.7 +/- 1 cm (P < 0.001) with dobutamine but did not change with low-level exercise (13 +/- 1 vs. 13.5 +/- 1, P = 0.5). CONCLUSION: Low-level exercise fails to elicit LV contractile reserve in patients with severe aortic stenosis, reduced LV systolic function, and low transvalvular gradient.
