Incorrect timing of end-systole

Varying approaches to defining end systole depending on the software. Some systems use beginning of QRS complex and end of T wave to define event timing and, thus, it is important to have a good quality electrocardiography tracing. Setting end systole too early or too late can affect peak strain in some segments and lead to inaccurate GLS measurement (Video 13). It is important to know timing of the strain measurement: peak strain from the entire cardiac cycle, peak systole, or end systole