In patients with asymptomatic aortic stenosis (AS), the prognostic value of reduced left ventricular (LV) ejection fraction is well known. Consequently, there is class I indication for surgery in these patients when LV ejection fraction <50%. However, there is growing evidences suggesting that subclinical LV dysfunction, and more particularly longitudinal myocardial dysfunction, may be a powerful early predictor of outcome, even when LV ejection is still preserved. In asymptomatic AS patients with LV ejection fraction >50%, a reduced LV global longitudinal strain, as assessed using speckle tracking imaging with transthoracic echocardiography, may be an accurate marker to identify early subclinical LV dysfunction and thus, to improve the risk stratification, the management and the timing of surgery. Several mono-centric observational small studies recently reported results emphasizing the role of LV global longitudinal strain in AS patients. Therefore, a meta-analysis may be conducted and may provide meaningful data. The investigators hypothesized that LV global longitudinal strain is a determinant of outcome in asymptomatic patients with AS and preserved LV ejection fraction.

Inclusion Criteria:

• studies selected in PubMed, Embase, Ovid, and Google Scholar, published between 2005 and 2015 without language restriction according to the following criteria: "aortic stenosis" AND "longitudinal strain"

Exclusion Criteria:

• Studies reporting global longitudinal strain derived from VVI and not speckle tracking analysis.
• Studies with cohort of patients with aortic valve replacement indication

Asymptomatic patients with at least moderate aortic stenosis (mean pressure gradient >25mmHg or aortic valve area <1.5cm²) and left ventricular ejection fraction >50%.