QUOTE: .....st depression is marker of what?
>>>>The ST segment can become either depressed or elevated for ventrical receiving an insufficient supply of blood and/ or the heart cells are difficient of oxygen (hypoxia). ,
QUOTE: is transmural mi is called q wave mi definitely?
is transmural mi is called q wave mi definitely?
>>>>>The presence of the Q wave in the absence of ST and T wave abnormality generally indicates prior or healed infarction. Q wave MI, which is diagnosed by the presence of pathological Q waves and is also called transmural infarction.
The classic changes of dead heart cells (Q waves), injury (ST elevation), and occluded vessels (partial blockage) causes T wave inversion and may all be seen during acute infarction.
"In recovery, the ST segment is the earliest change that normalizes, then the T wave; the Q wave usually persists. Therefore, the age of the infarction can be roughly estimated from the appearance of the ST segment and T wave. The presence of the Q wave in the absence of ST and T wave abnormality generally indicates prior or healed infarction."
Why there can be mixed EKG signals during an acute myocardial infarction, because the central area of dead cells is generally surrounded by an area of injury, which in turn is surrounded by an area of heart cells with insufficient oxygen so various stages of myocardial damage can coexist. The distinction between cells that lack good blood flow and dead cells is a determination whether the conditions are reversible.
Hope this helps give you a perspective, and EKG abnormal signals can be due to many non-cardiac conditions, so an EKG requires supporting other clinical evidence, symptoms, etc. Take care and thanks for the quesiton.