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61 Cards in this Set
- Front
- Back
How many major arterial systems supply blood to the myocardium?
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two
one supplies the right, the other the left |
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Name the two main arteries supplying the heart.
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right coronary artery
left main artery |
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coronary artery that runs between the right atrium and right ventricle and then swings around to the posterior surface of the heart
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right coronary artery
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In most individuals, the AV node is supplied by a descending branch of this artery.
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right coronary artery
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In about 10% of the population, the AV node is supplied by a branch of this artery.
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left circumflex artery
(off the left main artery) |
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vessel that supplies the left side of the heart; divides into two arteries
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left main artery
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left main artery divides into these two arteries
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left anterior descending artery (LAD)
left circumflex artery |
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artery that supplies the anterior wall of the heart and most of the interventricular septum
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left anterior descending (LAD)
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artery that runs between the left atrium and the left ventricle and supplies the lateral wall of the left ventricle
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circumflex artery
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Why is localization of an infarct important?
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Prognosis and therapy are in part determined by the location of the infarct.
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general anatomic categories of infarctions
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inferior infarctions
lateral infarctions anterior infarctions posterior infarctions (combinations, eg. "anteriolateral") |
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Almost all myocardial infarctions involve this part of the heart.
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left ventricle
|
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True or False:
Frequently, MI does not effect the left ventricle. |
False.
Almost all MIs involve the left ventricle. |
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In addition to the left ventricle, some inferior infarctions involve a portion of the ______.
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right ventricle
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True or False:
Left ventricle is most vulnerable to a compromised blood supply. |
True.
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In which leads do the electrocardiographic changes of infarction occur?
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only in those leads overlying or near the site of infarction
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infarction that involves the diaphragmatic surface of the heart
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inferior infarction
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infarction that is often caused by occlusion of the right coronary artery or its descending branch
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inferior infarction
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In which leads can an inferior infarction can be seen?
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the inferior leads
(II, III, AVF) |
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infarction that involves the left wall of the heart
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lateral infarction
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infarction often due to occlusion of the left circumflex artery
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lateral infarction
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In which leads can a lateral infarction be seen?
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lateral leads
(I, AVL, V5, V6) |
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infarction that involves the front surface of the left ventricle
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anterior infarction
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infarction usually caused by occlusion of the left anterior descending artery
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anterior infarction
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In which leads can an anterior infarction be seen?
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any of the precordial leads
(V1 through V6) |
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infarction that involves the rear surface of the heart and is usually caused by the occlusion of the right coronary artery
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posterior infarction
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In which leads can a posterior infarction be seen?
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as reciprocal changes in the anterior leads
especially V1 |
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What is a 15 lead EKG?
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An EKG with three extra leads for assessing posterior infarction. (rarely used) Extra leads are V8 and V9 (back) and V4R (right precordial).
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True or False:
Coronary anatomy can vary markedly among individuals, and the precise vessel involved may not always be what one would predict from the EKG. |
True.
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In which leads may reciprocal changes be seen in inferior infarctions?
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anterior and left lateral
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Which respective leads would show characteristic and reciprocal evidence of an inferior infarction?
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changes: II, III, AVF
reciprocal changes: anterior and left lateral leads |
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Which respective leads would show characteristic and reciprocal evidence of a lateral infarction?
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changes: I, AVL, V5, V6
reciprocal changes: inferior leads |
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Which respective leads would show characteristic and reciprocal evidence of an anterior infarction?
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changes: precordial (V1-V6)
reciprocal changes: inferior leads |
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Which respective leads would show characteristic and reciprocal evidence of a posterior infarction?
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characteristic changes: none, unless posterior leads are placed
reciprocal changes: anterior precordial leads, especially V1 |
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Although in most infarctions, Q waves remain for the life of the patient, what is the case with inferior infarctions?
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In about 50% of cases, Q waves disappear within half a year. (This is why small inferior Q waves *may* point to an old inferior infarction in which the Q waves have shrunk.)
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What may the presence of small Q waves inferiorly indicate?
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May be an old inferior infarction; may be nothing. Clinical history of the patient must be your guide.
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In which leads are reciprocal changes from lateral infarctions seen?
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inferior leads
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In which leads are reciprocal changes from anterior infarctions seen?
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inferior leads
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LAD occlusion may precipitate this event.
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anterior infarction
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Which leads may show characteristic changes in an anteriolateral infarction?
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precordial leads
leads I and AVL |
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True or False:
Loss of electrical forces anywhere in the heart will necessarily produce a Q wave in all leads except AVR. |
False.
The loss of anterior electrical forces in anterior infarction is not always associated with Q wave formation. |
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What can be said about precordial R wave progression in anterior infarctions?
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There may be a loss or dimishiment of the normal pattern of precordial R wave progression to indicate infarction, even if no Q wave are present.
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In normal hearts, the amplitude of R waves should progress at least ______ per lead as you progress from V1 to V4 or V5?
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1 mV
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1mV per lead R wave precordial lead progression typical of normal hearts may vanish with ______ infarctions.
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anterior
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True or False:
Even in the absence of significant Q waves, poor R wave progression may signify anterior infarction. |
True.
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Term used to describe vanished or diminished amplitude increase of R waves that is normally seen across precordial leads.
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poor R wave progression
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True or False:
Poor R wave progression is specific to the diagnosis of anterior infarction. |
False.
It can be seen often with improper lead placement. It is also seen in right ventricular hypertrophy and in patients with chronic lung disease. |
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In posterior infarction, because we can't look for ST elevation and Q waves in nonexistent posterior leads, we must look for ______ and ______ in the anterior leads, notably V1.
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ST depression
tall R waves |
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The normal QRS complex on V1 consists of a ______ R wave and a ______ S wave.
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small
deep |
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What should you look for in V1 in the presence of a posterior infarction?
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tall R wave with ST depression
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In V1, the presence of an R wave of greater amplitude than the corresponding S wave is highly suggestive of what?
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posterior infarction
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True or False:
In posterior infarction, because the inferior wall usually has the same blood supply as the posterior wall, there will often be evidence of accompanying infarction of the inferior wall. |
True
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In addition to posterior infarction, the presence of a large R wave exceeding the amplitude of the accompanying S wave in V1 is also one criterion for the diagnosis of ______.
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right ventricular hypertrophy
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How can you tell the difference between the EKG findings characteristic of posterior infarction and right ventricular hypertrophy?
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Right ventricular hypertrophy requires the presence of right axis deviation, which is not present in posterior infarction.
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True or False:
Not all myocardial infarctions produce Q waves. |
True
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Previously used in relation to non-Q wave infarctions, based on the largely discounted thinking that Q waves relate to the wall thickness of the infarction.
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transmural infarction
(full thickness) subendocardial infarction (inside thickness) |
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the only EKG changes seen with a non-Q wave infarction
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T-wave inversion and ST segment depression
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True or False:
A non-Q wave infarction may be either transmural or subendocardial. |
True.
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Non-Q wave infarctions have ______ initial mortality rate and ______ risk for later infarction and mortality.
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lower
higher |
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True or False:
Non-Q wave infarctions behave as incomplete infarctions. |
True.
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True or False:
Cardiologists are not overly concerned with non-Q wave infarctions. |
False.
Cardiologists take aggressive measures to prevent further infarction and death, because the risk of later infarction and mortality is very high. |