Background. The effect of stent size and number on left ventricular systolic function improvement after percutaneous coronary intervention (PCI) using drug eluting stent is not clear enough. Aim. To study short-term effect of stent size and number on left ventricular systolic function improvement after elective PCI. Material and methods. The study included 150 adult patients with electively stented left anterior descending artery lesion with drug-eluting stent. Patients were examined before PCI and 1 and 3 months after PCI using speckle tracking echocardiography. Results. Before revascularization, mean left ventricular ejection fraction was 51.2%±5.7, mean global longitudinal peak systolic strain (GLPSS) – -9.29±0.94%. One month after PCI, mean GLPSS increased significantly to -14.05±1.72% (p