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61 Cards in this Set

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How many major arterial systems supply blood to the myocardium?
two
one supplies the right,
the other the left
Name the two main arteries supplying the heart.
right coronary artery
left main artery
coronary artery that runs between the right atrium and right ventricle and then swings around to the posterior surface of the heart
right coronary artery
In most individuals, the AV node is supplied by a descending branch of this artery.
right coronary artery
In about 10% of the population, the AV node is supplied by a branch of this artery.
left circumflex artery
(off the left main artery)
vessel that supplies the left side of the heart; divides into two arteries
left main artery
left main artery divides into these two arteries
left anterior descending artery (LAD)
left circumflex artery
artery that supplies the anterior wall of the heart and most of the interventricular septum
left anterior descending (LAD)
artery that runs between the left atrium and the left ventricle and supplies the lateral wall of the left ventricle
circumflex artery
Why is localization of an infarct important?
Prognosis and therapy are in part determined by the location of the infarct.
general anatomic categories of infarctions
inferior infarctions
lateral infarctions
anterior infarctions
posterior infarctions
(combinations, eg. "anteriolateral")
Almost all myocardial infarctions involve this part of the heart.
left ventricle
True or False:
Frequently, MI does not effect the left ventricle.
False.
Almost all MIs involve the left ventricle.
In addition to the left ventricle, some inferior infarctions involve a portion of the ______.
right ventricle
True or False:
Left ventricle is most vulnerable to a compromised blood supply.
True.
In which leads do the electrocardiographic changes of infarction occur?
only in those leads overlying or near the site of infarction
infarction that involves the diaphragmatic surface of the heart
inferior infarction
infarction that is often caused by occlusion of the right coronary artery or its descending branch
inferior infarction
In which leads can an inferior infarction can be seen?
the inferior leads
(II, III, AVF)
infarction that involves the left wall of the heart
lateral infarction
infarction often due to occlusion of the left circumflex artery
lateral infarction
In which leads can a lateral infarction be seen?
lateral leads
(I, AVL, V5, V6)
infarction that involves the front surface of the left ventricle
anterior infarction
infarction usually caused by occlusion of the left anterior descending artery
anterior infarction
In which leads can an anterior infarction be seen?
any of the precordial leads
(V1 through V6)
infarction that involves the rear surface of the heart and is usually caused by the occlusion of the right coronary artery
posterior infarction
In which leads can a posterior infarction be seen?
as reciprocal changes in the anterior leads
especially V1
What is a 15 lead EKG?
An EKG with three extra leads for assessing posterior infarction. (rarely used) Extra leads are V8 and V9 (back) and V4R (right precordial).
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.
In which leads may reciprocal changes be seen in inferior infarctions?
anterior and left lateral
Which respective leads would show characteristic and reciprocal evidence of an inferior infarction?
changes: II, III, AVF

reciprocal changes: anterior and left lateral leads
Which respective leads would show characteristic and reciprocal evidence of a lateral infarction?
changes: I, AVL, V5, V6

reciprocal changes: inferior leads
Which respective leads would show characteristic and reciprocal evidence of an anterior infarction?
changes: precordial (V1-V6)

reciprocal changes: inferior leads
Which respective leads would show characteristic and reciprocal evidence of a posterior infarction?
characteristic changes: none, unless posterior leads are placed

reciprocal changes: anterior precordial leads, especially V1
Although in most infarctions, Q waves remain for the life of the patient, what is the case with inferior infarctions?
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.)
What may the presence of small Q waves inferiorly indicate?
May be an old inferior infarction; may be nothing. Clinical history of the patient must be your guide.
In which leads are reciprocal changes from lateral infarctions seen?
inferior leads
In which leads are reciprocal changes from anterior infarctions seen?
inferior leads
LAD occlusion may precipitate this event.
anterior infarction
Which leads may show characteristic changes in an anteriolateral infarction?
precordial leads
leads I and AVL
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.
What can be said about precordial R wave progression in anterior infarctions?
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.
In normal hearts, the amplitude of R waves should progress at least ______ per lead as you progress from V1 to V4 or V5?
1 mV
1mV per lead R wave precordial lead progression typical of normal hearts may vanish with ______ infarctions.
anterior
True or False:
Even in the absence of significant Q waves, poor R wave progression may signify anterior infarction.
True.
Term used to describe vanished or diminished amplitude increase of R waves that is normally seen across precordial leads.
poor R wave progression
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.
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.
ST depression

tall R waves
The normal QRS complex on V1 consists of a ______ R wave and a ______ S wave.
small

deep
What should you look for in V1 in the presence of a posterior infarction?
tall R wave with ST depression
In V1, the presence of an R wave of greater amplitude than the corresponding S wave is highly suggestive of what?
posterior infarction
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
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 ______.
right ventricular hypertrophy
How can you tell the difference between the EKG findings characteristic of posterior infarction and right ventricular hypertrophy?
Right ventricular hypertrophy requires the presence of right axis deviation, which is not present in posterior infarction.
True or False:
Not all myocardial infarctions produce Q waves.
True
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.
transmural infarction
(full thickness)

subendocardial infarction
(inside thickness)
the only EKG changes seen with a non-Q wave infarction
T-wave inversion and ST segment depression
True or False:
A non-Q wave infarction may be either transmural or subendocardial.
True.
Non-Q wave infarctions have ______ initial mortality rate and ______ risk for later infarction and mortality.
lower

higher
True or False:
Non-Q wave infarctions behave as incomplete infarctions.
True.
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.