2.3. Assessment of aortic strain
Aortic root, AoS and AoD was measured by 2D motion mode (M-mode) transthoracic echocardiography at a level of 3–4 cm above the aortic valve from a transthoracic parasternal long-axis view, at the time of maximum aortic anterior motion, and at the peak of the QRS complex at the simultaneous electrocardiogram recording, respectively. The percentage change in the aortic root was calculated as DAo% = 100 × (AoS ˗ AoD) / AoD to obtain aortic strain (9).