Chapter 9: Infarction Flashcards
A coronary artery can be gradually narrowed by lipid deposits that become ____________ ______ beneath the ______ ______ of the vessel. The intima may eventually rupture, exposing the plaque to the blood within the artery. This initiates the formation of a ________.
atheromatous plaque
intima lining
thrombus
(p. 259)
The EKG can tell us which ________ ______ is occluded, and can even reveal any ______ in the ventricular conduction caused by the infarction.
coronary artery
blocks
(p. 259)
The coronary arteries originate at the…
…base of the aorta.
p. 260
Necrotic, infarcted tissue cannot…
…depolarize.
p. 262
Hypoxic ventricular foci in the area of necrosis are often the source of…
…serious ventricular arrhythmias.
p. 262
The myocardial infarction triad is ________, ______, and ________, but any of the 3 may occur alone.
Also, not all 3 need to be present in order to _________ myocardial infarction.
ischemia, injury, necrosis
diagnose
(p. 263)
The term “ischemia” literally means…
…reduced blood supply.
p. 263
The characteristic sign of ischemia on EKG is…
…inverted T waves.
p. 264
Angina is usually associated with…
…transient T wave inversion.
p. 264
In adults, flat (nonexistent) T waves or minimal T wave inversion may be a ______ _______ in any of the LIMB leads.
normal variant (p. 265)
However, any T wave inversion in leads __ through __ is considered pathological.
V2 through V6
p. 265
Marked T wave inversion in leads V2 and V3, the hallmark of _______ ________, alerts us to ________ of the anterior __________ coronary.
Wellens syndrome
stenosis
descending
(p. 265)
Elevation of the ST segment signifies…
It tells us that an MI is…
…“injury”.
…acute (recent).
p. 266
Angina without exertion, “Prinzmetal’s” angina, can cause _________ __ _________ in the absence of an infarction.
transient ST elevation
p. 266
If the ST segment is elevated without associated _ _____, this may represent ___-_ ____ __________.
Q waves, non-Q wave infarction
p. 267
A ventricular aneurysm can cause persistent ST elevation in…
…most of the chest leads, and the ST segment does NOT return to the baseline with time.
(p. 267)
Pericarditis produces a unique type of ST segment elevation that may also elevate the _ ____ off the baseline.
T wave
p. 267
______ _______ _____ can occur spontaneously in patients with Brugada syndrome.
Sudden cardiac death
p. 268
Brugada syndrome is a __________ condition, characterized by RBBB and ST elevation in leads __ to __.
hereditary, V1 to V3
p. 268
Brugada syndrome is caused by dysfunctional…
Prophylaxis against the deadly arrhythmias that can result requires…
…cardiac sodium channels.
…ICD implantation.
p. 268
Brugada syndrome is responsible for nearly _______ of the sudden deaths in healthy young individuals without structural heart disease.
one-half
p. 268
Pericarditis may be caused by…
…a virus, bacteria, cancer, or other sources of inflammation, including MI.
(p. 269)
With pericarditis, the ST segment is elevated and usually ____ or _______.
flat or concave
p. 269
Name the 3 conditions under which the ST segment may become depressed:
subendocardial infarction
positive stress test
digitalis
(p. 270)
A subendocardial infarction does not extend through the ____ _________ of the ventricular ____.
full thickness
wall
(p. 270)
Subendocardial infarction is a type of _________ MI, and is identified by ____ __ _______ __________.
non-Q wave
flat ST segment depression
(p. 271)
While classic MI is transmural, a subendocardial infarction must be respected as a ____ __.
true MI (p. 271)
The Q wave is the _____ ________ stroke of the QRS complex, and it is never ________ by anything in the complex. If there is any positive wave, even a tiny spike, before the downward wave, the downward wave is an _ ____ and the upward wave preceding it is an _ ____.
first downward, preceded
S wave, R wave
(p. 272)
Significant Q waves are ______ in normal tracings.
absent
p. 272
A significant Q wave indicates ________ and is diagnostic for __________.
necrosis, infarction
p. 272
A (capital) Q wave is ________, but smaller q waves (lowercase letter) are not significant.
abnormal
p. 273
Normally, ventricular depolarization begins ______ down the interventricular septum. Septal depolarization (initiated at mid-septum by the ____ Bundle Branch) is _____-to-_____, and this initial rightward ventricular activation may produce tiny, insignificant q waves in leads where the QRS is usually _______.
midway
Left, left-to-right
upright
(p. 273)
Insignificant q waves are, by definition…
…less than one millimeter (0.04 sec) in duration.
p. 273
A significant Q wave is at least…
…one small square (0.04 sec) wide, or one-third of the entire QRS amplitude.
To check for an infarction, we scan all leads (EXCEPT FOR ___!) for the presence of significant Q waves.
AVR
p. 275
We do not assess lead AVR for Q waves because the lead is…
Basically, lead AVR is like an ___________ lead __, so the large Q waves that are commonly seen in lead AVR are really…
…positioned in such a way that data about Q waves are unreliable.
upside-down, II
…upside down R waves from lead II.
(p. 275)
An infarct is necrotic; it cannot depolarize and it has no _______. Therefore, the positive electrode nearest the _________ area detects no “toward” or “positive” vectors. A Q wave in inscribed on EKG in the leads which use that positive electrode for recording.
vectors
infarcted
(p. 277)
An anterior infarct will show Q waves in…
…V1 through V4.
p. 277
A lateral infarct will show Q waves in…
…leads I and AVL.
p. 277
An inferior infarct will show Q waves in…
…leads II, III, and AVF.
p. 277
An infarction evidenced by Q waves in V1 and V2 includes the septum and is called an…
…anteroseptal infarction.
p. 278
An infarction evidenced by Q waves in V3 and V4 is called an…
…anterolateral infarction.
p. 278
And remember that insignificant q waves are seen normally in…
…V5 and V6.
p. 278
The lateral limb leads use the ____ ___ as the positive electrode.
The inferior limb leads use the ____ ____ as the positive electrode.
left arm
left foot
p. 279
Diaphragmatic infarct is synonymous with…
…inferior infarct.
p. 281
Autopsy data show that about _________ of inferior infarctions also include portions of the _____ _________.
one-third
right ventricle
(p. 281)
Left ventricular depolarization may be said to proceed from the ___________ (inner lining) to the __________ (outer surface).
endocardium
epicardium
(p. 282)
If an acute anterior infarction produces Q waves and ST elevation in V1 and V2, then a posterior infarction would…
…appear the opposite.
p. 283
In acute POSTERIOR infarction, there is a large _ ____ (the opposite of a _ ____) in V1 and V2, and ST __________ instead of _________.
Remember that R waves in lead I are normally ____ ____.
R wave, Q wave
depression, elevation
very tiny
(p. 284)
If you suspect an acute posterior infarction (due to large R wave and ST depression in V1 or V2) then try “reversed trans-illumination” or the “mirror test”. These tests require _________ the EKG tracing, then either holding it to a strong light and looking at the back unprinted side, or _________ and then looking at it in a mirror. Now you can see Q waves and ST elevation, just as if it were an ________ infarct.
inverting, inverting
anterior
(p. 287)
The EKG diagnosis of infarction is generally not valid in the presence of ____ ______ ______ _____.
So, any Q wave originating in the L ventricle could not appear at the beginning of the QRS complex with LBBB; rather it would fall somewhere in the ______ of the QRS complex, making it difficult to detect significant Q waves.
One special exception is possible. The R and L ventricles share the interventricular septum in common. So, an infarct in the septal area would be shared by the right ventricle, which depolarizes _____ in LBBB. This would produce Q waves at the beginning of the wide QRS. Therefore, even in the presence of LBBB, Q waves in the chest leads might suggest (but not _______) antero-septal infarction.
left bundle branch block middle first confirm (p. 289)
The two main arteries of the heart are the ____ and _____ coronary arteries.
The major branches of the ____ coronary artery are the __________ and the ________ __________.
left and right
left, circumflex, anterior descending
(p. 291)
A lateral infarction is caused by occlusion of the…
…circumflex branch of the left coronary artery
p. 292
An anterior infarction is caused by occlusion of the…
…anterior descending branch of the left coronary artery.
p. 292
The posterior portion of the left ventricle is supplied by the…
…right coronary artery which wraps around the right ventricle.
(p. 293)
True posterior infarctions are generally caused by an occlusion of the…
…right coronary artery or one of its branches.
p. 293
In addition, the right coronary artery usually supplies blood also to the…
This is why acute posterior infarctions are often associated with…
…SA Node, AV Node, and His bundle.
…serious arrhythmias.
p. 293
The hemiblocks are blocks of either the ________ or the _________ division of the LEFT bundle branch.
anterior, posterior
p. 295
The _____ bundle branch does not have consistent, named ____________ of either clinical or electrocardiographic importance (yet).
RIGHT, subdivisions
p. 295
The word “fascicle” means ______, so any main division of the ventricular conduction system is a fascicle. ____ Bundle Branches as well as both divisions of the LBB are fascicles.
bundle
both
(p. 303)
Note: pp. 296 - 302 were skipped.
This material is not on the exam.
The EKG has never become obsolete because it provides…
…more cardiac information than any other diagnostic modality. (?? echo??)
(p. 307)
