The Relationship Between ST Elevation and ST Depression in Acute MI

To evaluate the ST segment, we need to look at the QRS that precedes it and the T waves that follow. Left bunnabranch block or LVH cause discordant anterior ST elevation and discordant lateral ST depression. If the QRS is abnormal, this can cause secondary ST and T wave changes discordant to the QRS. St elevation from parachiditis is diffuse and concave without preceding Q waves and without abnormal T waves following it.