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.
What is deepened Q wave?
Q waves are considered pathological if: > 40 ms (1 mm) wide. > 2 mm deep. > 25% of depth of QRS complex. Seen in leads V1-3.
What is Q wave infarction?
Q wave myocardial infarction refers to myocardial infarctions that in a Q wave forming on the 12-lead ECG once the infarction is completed.
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 causes pathologic Q waves?
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 would be expected when evaluating an ECG for a lateral infarction?
High Lateral STEMI: ST elevation is present in the high lateral leads (I and aVL). There is reciprocal ST depression in the inferior leads (III and aVF). QS waves in the anteroseptal leads (V1-4) with poor R wave progression indicate prior anteroseptal infarction.
When do Q waves appear after MI?
Q waves may develop within one to two hours of the onset of symptoms of acute myocardial infarction, though often they take 12 hours and occasionally up to 24 hours to appear.
What does lateral infarct mean on ECG?
A lateral myocardial infarction (MI) is a heart attack or cessation of blood flow to the heart muscle that involves the inferior side of the heart. Inferior MI results from the total occlusion of the left circumflex artery. Lateral MI is characterized by ST elevation on the electrocardiogram (EKG) in leads I and aVL.
