ECG changes in acute MI

The ECG changes are often  critical in the diagnosis of acute MI and guiding therapy.
There is a series of ECG changes reflect the evolution of the infarction (The Figure below).
1.The earliest changes are : tall, positive, hyper acute T waves in the ischemic vascular territory.
2.This is followed by elevation of the ST segments (myocardial “injury pattern”).
3.Over hours to days, T-wave inversion frequently develops.
4.And finally, diminished R-wave amplitude or Q waves occur, representing significant myocardial necrosis and replacement by scar tissue, and they are what one seeks to prevent in treating the acute MI .

 Temporal evolution of ECG changes in acute myocardial infarction.

Note the tall hyperacute T waves and loss of R-wave amplitude,followed by ST-segment elevation,T-wave inversion,and development of Q waves.Persistent ST-segment elevation suggests left ventricular aneurysm.