Defining peak longitudinal strain and post systolic shortening
Peak longitudinal systolic strain (PLS) was measured as the maximum value of strain in systole, which was defined as the time interval between the aortic valve opening and closure. Strain values were also evaluated segmentally according to the area at risk. Values above -18 were considered significant for PLS.
PSS is described as myocardial contraction that occur after end systole or aortic valve closure. Criteria for pathologic PSS was, when PSS exceeds 20% of ejection time and when it takes more than 90 ms after AVC (5).