What is the difference between transmural MI and subendocardial MI?

What is the difference between transmural MI and subendocardial MI?

The transmural type usually consisted of yellowish-brown coagulation necrosis in the center of an infarcted focus and coagulative myocytolysis at the marginal zone. The subendocardial type was characterized by coagulative myocytolysis throughout the entire focus.

What is transmural Q wave infarction?

A transmural myocardial infarction refers to a myocardial infarction that involves the full thickness of the myocardium. It was one believed that the development of Q waves indicated the infarction was “transmural;” however, autopsy studies failed to confirm this.

What is the significance of Q wave in MI?

This is part of: Myocardial Infarction Pathologic Q waves are a sign of previous myocardial infarction. They are the result of absence of electrical activity. A myocardial infarction can be thought of as an elecrical ‘hole’ as scar tissue is electrically dead and therefore results in pathologic Q waves.

What is a Subendocardial MI?

A subendocardial infarct results in necrosis exclusively inolving the innermost aspect of the myocardium. Usually a subendocardial infarct is the result of a partially occluded epicardial coronary artery (i.e. NSTEMI).

What is transmural myocardial ischemia?

When a sudden, complete occlusion of a coronary artery prevents blood flow from reaching an area of myocardium, the resulting transmural myocardial ischemia 4–6 is manifested by deviation of the ST segment toward the involved region.

Is transmural MI the same as stemi?

ST-segment elevation myocardial infarction (STEMI, transmural MI) is myocardial necrosis with ECG changes showing ST-segment elevation that is not quickly reversed by nitroglycerin. Troponin I or troponin T and CK are elevated.

What do Q waves indicate?

Technically, a Q wave indicates that the net direction of early ventricular depolarization (QRS) electrical forces projects toward the negative pole of the lead axis in question. Although prominent Q waves are a characteristic finding in myocardial infarction, they can also be seen in a number of noninfarct settings.

Why are there no Q waves in Nstemi?

Pathological (infarction) Q-waves Pathological Q-waves arise arise if the infarction is extensive, which is usually not the case in patients with NSTEMI. Hence, patients with NSTEMI typically do not develop pathological Q-waves.

Are Q waves always pathological?

Q waves in the right precordium are always pathologic and are commonly associated with right ventricular hypertrophy.

What causes abnormal Q waves?

The majority of abnormal Q waves are due to myocardial infarction, although other causes clearly must be considered. Non–Q-wave myocardial infarction may be transient or permanent. Transient Q waves have been produced experimentally in animals and have been observed in patients during ischemic episodes.

What does Subendocardial ischemia mean?

Abstract. Most forms of heart disease cause myocardial damage which often is confined to the deep (subendocardial) layer of left ventricular muscle. Much clinical and experimental evidence suggests that subendocardial muscle is prone to ischaemic damage, and a physiological mechanism for this vulnerability is described …

What is Subendocardial MI?

What is Subendocardial?

Medical Definition of subendocardial : situated or occurring beneath the endocardium or between the endocardium and myocardium subendocardial blood loss.

Which leads are Q waves normal?

A Q-wave may also be normal in aVL if the frontal QRS axis is between 60o and 90o. Septal Q-waves are small, nonpathological Q-waves <0.03 s and <0.25 of the R-wave amplitude in leads I, aVL, aVF, and V4–V6.

Are Q waves seen in NSTEMI?

Do NSTEMI develop Q waves?

A certain number of patients with NSTEMI develop Q waves. Other problems defying accurate definition of NSTEMI include the inability to determine whether a transient ST elevation had preceded the first available ECG and the possibility of unrecognized ST segment elevation in some leads, particularly the lead aVR.