Chapter 14: Myocardial Infarction
How is a posterior MI diagnosed?
By a mirror image of the normal indicative changes of an MI in V1 to V2.
If the location of the STEMI is laterla, what are the EKG changes and what use the correlating coronary artery?
-EKG CHANGES: Indicative changes in I, aVL, V5 to V6 May see reciprocal changes in II, III, aVF -CORONARY ARTERY: circumflex
If the location of the STEMI is inferior, what are the EKG changes and what use the correlating coronary artery?
-EKG CHANGES: Indicative changes in II, III, aVF Reciprocal changes in I, aVL, and V leads -CORONARY ARTERY: Right coronary artery (RCA)
If the location of the STEMI is anteroseptal, what are the EKG changes and what use the correlating coronary artery?
-EKG CHANGES: Indicative changes in V1 plus any anterior lead(s) Usually no reciprocal changes -CORONARY ARTERY: LAD
If the location of the STEMI is anterior, what are the EKG changes and what use the correlating coronary artery?
-EKG CHANGES: Indicative changes in V2 to V4 Reciprocal changes in II, III, aVF -CORONARY ARTERY: Left anterior descending (LAD)
If the location of the STEMI is posterior, what are the EKG changes and what use the correlating coronary artery?
-EKG CHANGES: No indicative changes, because no leads look directly at posterior wall Diagnosed by reciprocal changes in V1 and V2 (large R wave, upright T wave, and possibly ST depression). SEen as a mirror image of an anterior MI -CORONARY ARTERY: Is not listed in text
What is a normal variant sometimes seen in young people, especially young black males?
-Early repolarization which results in ST elevation that may be convex or concave
What have experiments on dogs revealed about MIs?
-Experiments on dogs have shown that almost immediately after a coronary artery becomes occluded, the T wave invests in the EKG leads overlooking the occluded area
What damages do ischemia and injury cause? What damages do infarction cause?
-Ischemia and injury to myocardial tissue and cause repolarization changes, so the ST segments and the T waves will be abnormal -Infarction causes depolarization changes, so the ARS complex will show telltale signs of permanent damage
What is the end result/damage/reversibility of possible damage of ischemia, injury and infarction?
-Ischemia no injury are reversible if circulation is restored -Once the tissue has infarcted, however, the tissue is permanently dead -Myocardial cells do not regenerate
Why is MI pain dangerous to the patient?
-It increases heart rate and stressed the heart even more -Relieving pain is extremely important
What are thrombolytic?
-Medications that dissolve blood clots
What are the EKG complications of anterior MI?
-Mobitz II second-degree AV block -Third degree AV block with wide QRS, V-fib in early hours, RBBB, LPHB, AIVR, sinus tachycardia, ventricular arrhythmias
What is ST segment elevation most often associated with? However, what can it also imply?
-Most often associated with an MI in progress -There are times when it may instead imply an inflammation of the pericardium, called pericarditis
If occlusion persists, what happens to the jeopardized myocardial tissue?
-Myocardial tissue necrosis (dies) and turns black -In time, the dead tissue will become scar tissue
Which MI is typically difficult to diagnose and why?
-NSTEMIs (non-ST elevation MIs) because they do not result in the typical EKG changes associated with STEMIs (ST elevation MIs)
Where do infarctions mostly occur and why?
-Occur mostly in the left ventricle because it has the greatest demand and thus is impacted more adversely by poor coronary artery flow
What is ischemia?
-Oxygen deprivation in the tissues
What is the treatment for suspected MI patients?
-Patients will be started on oxygen y nasal cannula to decrease the heart's workload -They'll be given nitroglycerin and perhaps morphine for chest pain
How do diabetes feel/express their pain of MIs?
-Patients with long time diabetes may not have chest or other discomfort with their MI -They can have a condition called neuropathy, which results in diminished pain sensation
If you turn the EKG upside down, and there is a significant Q wave and T wave inversion in V1 and V2 in this upside-down reverse approach, there is a ____________. What will the ST segment be like?
-Posterior MI -The ST segment may be elevated or at baseline, depending on the age of the MI
As the QRS travels through the leads, describe if the QRS is negative or positive.
-QRS starts out primarily negative in V1 and goes through a transition around V3 or V4, where the QRS is isoelectric -The QRS then ends up primarily positive by V6
EKG has ST elevation in Leads V1 to V2. What is the diagnosis?
-RECALL V1 is a septal lead and V2 is an anterior lead -The combination of V1 plus any anterior lead results in an anteroseptal MI
What does the American Heart Association and American College of Cardiology recommend in the treatment of STEMI patients?
-Recommends that they be immediately taken to the cardiac catheterization lab for reperfusion via PCI (percutaneous coronary intervention), a ballon procedure to pen the blocked coronary artery -A wire mesh called a stent may then be placed at the site of the former blockage to act as a sort of scaffold to keep the artery open
What does subendocardial mean?
-Referring to the myocardial layer just beneath the endocardium
What does early repolarization look like on the EKG?
-Repolarization begins so early in this condition that the ST segment appears to start even before the QRS complex has finished, making it appear that the ST segment is mildly elevated -Often there is a "fishhook" at the end of some of the QTS complexes that makes recognition of early repolarization easier
What are the characteristics of a normal T wave?
-Rounded with an amplitude less than or equal to 5 mm in the frontal leads and should be upright in all leads except a VR and V1 -aVR's T waves hould be negative -V1's T wave can be lat, inverted or upright
What are the two types of myocardial infarction?
-ST elevation MIs (STEMI) And -non-ST elevation MIs (NSTEMI)
To determine if an MI is present, what three parts of the EKG do we look at?
-ST segments -T waves -the QRS complexes
At some smaller hospital without cardiac catheterization labs, PCI is not possible, so how are STEMI patients treated?
-STEMI patients at these facilities can either be transported to a. Nearby facility that can do the PCI within the 90 minutes or they can be treated with thrombolytic medications (medications that dissolve blood blots) within 30 minutes of arriving at the smaller hospital
What are other symptoms of MI?
-Shortness of breath -Nausea/vomiting -Pallor -Diaphoresis -Arrhythmias -Not all patients with MI will have all these symptoms
Describe the normal ST segment.
-Should be on the baseline at the same level as the PR segment -Think of the PR segment as the baseline for ST segment evaluation purposes
What should be done to patients suspected of having an MI?
-Should have a 12-lead ekg and blood drawn to determine if an MI is in progress
What are the characteristics of QRS complexes in MIs? What does it mean for a Q wave to be significant?
-Significant Q waves and poor R wave progression as clues to an AMI -For a Q wave to be significant, it must be either 0.04 seconds (one little block) wide or at least one-third the size of the R wave
What appears on the EKGs in STEMIs?
-Significant Q waves develop on the EKG
What are silent MIs and which demographic of people tend to have them?
-Silent MIs are those that show up, perhaps on a. Routine EKG at the physician's office, without the typical signs and symptoms
What conditions are common following an MI?
-Sinus tachycardia -Decreased diastolic filling time (Heart rate raises too high and there is not enough time in between beats for the heart to fill up with blood) -Cardiogenic shock (a type of shock caused by catastrophic heart failure) -Arrhythmias (Ventricular fibrillation)
What condition is common after an MI and why?
-Sinus tachycardia because the heart can't pump out as much blood as before so it compensates by pumping out more often
Where do leads V2 through V4 sit and what do they look at?
-Sit right in front of the heart -Looking at the anterior wall
The NSTEMI tends to be _________ or __________.
-Subendocardial or incomplete -Means damaging only the innermost layer of the myocardium just beneath the endocardium
What occurs on the EKG which is a characteristic of injury?
-The ST segment arises, indicating a current of injury and the beginning of an acute STEMI
How can we tell that myocardial tissue is ischemic from viewing an EKG?
-The T wave inverts in the EKG leads overlooking the occluded area -Myocardial tissue is ischemic, starving for blood and oxygen due to the lack of blood flow
What is MONA?
-The combination of meds used to treat MI patients -Morphine, oxygen, nitroglycerin, aspirin
What do the positive poles of Leads II, III, and aVF look at?
-The heart from the bottom -Views the inferior wall of the left ventricle
What is the infarcted zone?
-The innermost zone which has been deprived of oxygen the longest, as it's the deepest layer and thus farthest away from the blood supply
If occlusion persists after ischemia and injury, what occurs in both the heart and the EKG?
-The jeopardized myocardial tissue endorses (dies) and turns black -Significant Q waves develop (in STEMIs) on the EKG -In time, the dead tissue will become scar tissue
What is the transition zone? When does it occur normally?
-The lead in which the QRS becomes isoelectric -Should normally occur between V3 and V4
With NSTEMIs, what symptoms do patients typically have?
-The patient will have the usual symptoms of an MI
What is the three I's of Infarction?
-The sequence of events that occurs when a coronary artery becomes occluded 1) Ischemia 2) Injury 3) Infarction
What is the ischemic zone?
-The zone immediately surrounded the injured zone
What is the injured zone?
-The zone immediately surrounding the infarcted zone
Describe abormal ST segments.
-They are elevated or depressed
What are the characteristics of normal Q waves
-They imply septal and right ventricular deplarizaiton
How can NSTEMIs be diagnosed?
-They present ST segment depression and T wave inversion -At other times, the MI is diagnosed only by patient history, ST segment changes, and elevated lab values that indicate myocardial damage
If the R waves do not get progressively larger in the precordial leads, what should this imply?
-This can imply myocardial infarction -Sometimes poor R wave progression is the only electrocardiographic evidence of an MI
What are hyperacute changes
-Those that accompany an MI in its earliest stages -or "those seen int he earliest stages of a disease or condition"
What is the downside to treating patients witH thrombolytics with MIs?
-Thrombolytics dissolve the blood clot causing the MI, but they can only be given to a closely screened population of patients because of the increased risk of bleeding, which can cause strokes or other complications
What does transmural mean?
-Through the full thickness of the wall at that location
How do you see if the ST segment is abnormal?
-To see if the ST segment is elevated or depressed, draw a straight line extending from the PR segment out past the QRS -An elevated ST segment is one that is above this line -A depressed ST segment si one that is below this line
What is an easy way to find posterior MIs?
-To turn the EKG upside down (make the top the bottom) and look at V1 and V2 from the back of the EKG -This mimics that the EKG would look like if we had leads directly over the posterior wall
How is the posterior wall of the heart viewed?
-Unlike the other infarct locations, there are no leads looking looking directly at the posterior wall because we do not put EKG electrodes on the patients back for a routine 12-lead EKG -Therefore, the only way to look at the posterior wall is to look through the anterior wall
Which type of arrhythmias are common following an MI?
-Ventricular fibrillation
The myocardium is very ______________ during/after MI and ___________ often result.
-Very irritable -Ventricular arrhythmias
EKG has widespread concave ST elevation in Leads I, II, III, aVL, aVF, and V1 to V6. What is the diagnosis?
-Widespread concave ST elevation is not typical of an MI because it is so widespread -It is possible that this is a huge MI instead of pericarditis. HOWEVER, based not he concave ST elevation scattered across many leads, its more likely that its pericarditis.
An MI that has ST segment elevation is _________.
-acute (one to two days old or less)
An MI with significant Q waves, baseline (or almost back to baseline) ST segments, and interested T waves is of _________.
-age indeterminate (several days old, up to a year in some cases) -Some authorities call this a recent MI
What occurs during a myocardial infarction?
-death of myocardial tissue in an are deprived of blood flow by an occlusion (blockage) of a coronary artery
How do patients often describe the pain of MIs?
-left sided chest tightness -heaviness -pressure -"An elephant sitting on the chest" Or some variation of those
Right ventricular infarction: 1) What does it accompany 2) How is it diagnosed?
1) Accompanies inferior wall MI 2) Diagnosed by seeing ST elevation in V3 to V4R on right-sided EKG
What is acute, age indeterminate, and old "age of STEMIs"?
1) Acute = ST elevation 2) Age indeterminate = Significant Q wave, ST back (or almost back) to baseline, T wave inverted 3) Old = significant Q wave, ST at baseline, T wave upright
Convex ST segment elevation: 1) What is it also called? 2) What is it most often associated with?
1) Also called a coved ST segment 2) most often associated with a STEMI in progress
Wall of the left ventricle... What arteries are they fed by? 1) Anterior 2) Inferior 3) Lateral 4) Posterior
1) Fed by left anterior descending coronary artery 2) Fed by right coronary artery 3) Fed by circumflex 4) Fed by right coronary artery
In order to diagnose a RV infarction, what are the two conditions that must be met?
1) First, there must be an electrocardiographic evidence of an inferior wall MI on a standard 12-lead EKG 2) Second, a right-side EKG must reveal ST elevation in V3R and/or V4R
Pericarditis: 1) What is it? 2) How is it diagnosed?
1) Inflammation of pericardial sac--also inflames myocardium 2) Causes. Concave ST elevation (smiley face). ST elevation widespread
What are the three I's of infarction?
1) Ischemia: Decreased blood flow to heart muscle --tissue pale whitish--inverted T wave on EKG 2) Injury: Tissue injured by continued lack of blood flow--tissue bluish--ST segment elevation 3) Infarction: Tissue dies and turns black--significant Q waves
Where can pain be felt in the early signs of acute coronary syndrome (heart attack)?
1) Just under sternum, midchest, or the entire upper chest 2) Midchest, neck and jaw 3) Midchest and the shoulder and inside arms (more frequently the left) 4) Upper abdomen, often mistaken for indigestion 5) Larger area of the chest, plus neck, jaw and inside arms 6) Jaw from ear to ear, in both sides of upper neck, and in lower center neck 7) Shoulder (usually left) and inside arm to the waist, plus opposite arm, inside to the elbow 8) Between the shoulder blades
What is the STEMI criteria (what shows up on the EKG) for: 1) Anterior 2) Inferior 3) Lateral 4) Posterior 5) Extensive anterior 6) Anteroseptal
1) ST elevation V2 to V4 2) ST elevation II, III, aVF 3) ST elevation I, aVL, V5 to V6 4) ST depression and large R wave in V1 to V2 5) ST elevation I, AVL, all V leads 6) ST elevation V1 plus any other lead form V2 to V4
How do NSTEMIs affect the following: 1) ST segment 2) T wave
1) ST segment depression 2) T wave inversion
How do STEMIs affect the following? 1) ST segment 2) T wave inversion 3) Q waves
1) ST segment elevation 2) T wave inversion 3) Significant Q waves
What are the two types of MI?
1) STEMI - ST elevation MI 2) NSTEMI - Non-ST elevation MI
Early repolarization: 1) Who is it common in? 2) What does it cause on the EKG?
1) Young people, especially young black males 2) Causes mild ST elevation--sometimes see "fishhook" at end of QRS complexes in V leads
STEMIs occur over ___________.
A period of time
The classic symptom of an MI, whether STEMI or NSTEMI, is _____________.
Chest pain
What does angina mean?
Chest pain
ST elevation can be either ___________ or __________.
Concave or convex
______ and ______ are notoriosu for having atypical symptoms (or no symptoms at all) of their MI.
Females and diabetics
MIs can defect any of the _______.
Four walls of the left ventricle
How do the ventricles depolarize?
From endocardium to epicardium (from inside to outside)
If an hour later, Mr. Milner is doubled over with crushing chest pain and his EKG now shows marked ST elevation in II, III, aVF and V5 to V6, what is happening?
He is now injuring the inferior and lateral wall of the left ventricle. This is an acute MI in progress, which is reversible if he receives PCI or thrombolytic medications. IF the MI in progress is untreated, myocardial tissue will die and significant Q waves will develop in the inferior and lateral leads on his EKG
What are RV infarctions?
Heart attacks which occur when the blockage to the right coronary artery system is so extensive that damage extends into the right ventricle
What can a tall, pointy T wave be a signal of?
Hyperkalemia or hyperacute changes of an MI in progress
How are ischemia and injury reversible?
If circulation is restored
How can the heart's attempt to pump out more blood after a heart attack backfire?
If the heart rate rises too high, there is not enough time in betwen beats for the heart to fill back up with blood--referred to as decreased diastolic filling time--so the cardiac output drops even more
8) If the transition zone of the precordial ends in in V1 to V2, which kind of rotation is heart said to have?
If the transition zone is in V1 to V2, there is counterclockwise rotation of the heart
6) If there is a marked ST elevation in Leads II, III, and aVF, how old is the MI and in which wall of the heart?
If there is ST elevation in II, III, and aVF, the MI is acute inferior
7) If there is a significant Q wave in V1 to V3 with baseline ST segments and upright T waves, how old is the MI and in which wall of the heart?
If there is a significant Q wave in V1 to V3 with baseline ST segments and upright T waves, the MI is an old anteroseptal MI
In lead aVR, which wall of the heart does it look at?
Ignore this lead when looking for MIs
Can MIs travel across the heart?
In a sense, MIs can extend across into other walls as well -For example, a patient might have an inferior-lateral MI, which would involve the inferior leads as well as the lateral leads
A STEMI is diagnosed on the EKG by ____________ in the leads for the area.
Indicative changes (i.e. ST elevation, T wave inversion, and significant Q waves)
When an EKG is interpreted, the interpreter does not necessarily know the patient's clinical status and therefore must base determination of the MI's age on the ________.
Indicative changes present on the EKG
In lead II, which wall of the heart does it look at?
Inferior
In lead III, which wall of the heart does it look at?
Inferior
In lead aVF, which wall of the heart does it look at?
Inferior
What is pericarditis
Inflammation of the pericardium
Treatment of STEMIS and NSTEMIS differ after _______ and ______.
Initial treatment and diagnostic workup
How does nitroglycerin help suspected MI patients?
Nitroglycerin dilates (opens up) the narrowed coronary artery, allowing more blood flow tot he stricken myocardium. This can relive pain.
Depending on the age of the infarct, ______________ will be present.
Not all of those indicative changges
3) Which coronary artery's occlusion results in an anterior wall MI?
Occlusion of the left anterior descending coronary artery causes anterior MI
The MI with significant Q waves, baseline ST segments, and upright T waves is ________.
Old (weeks to years old)
EKG has significant Q waves remaining in V1 to V2. ST segments would be at baseline and the T waves would be upright. What is the diagnosis?
Old anteroseptal MI
EKG has only significant Q waves in II, III, and aVF. The ST segments would be at baseline and T waves would be upright. What is the diagnosis?
Old inferior MI
EKG has baseline ST segments, significant Q waves, and upright T waves in I, AVL, and V5 to V6. What is the diagnosis?
Old lateral wall MI
If there is only a little ST elevation in the indicative leads, there should be _____________________.
Only a little depression in the reciprocal leads
When is the only time a right-sided EKG is done?
Only if an RV infarction is suspected (i.e. The patient. Exhibits symptoms, particularly hypotension, beyond what is expected with just an inferior MI)
How are NSTEMIs diagnosed?
Only in the acute phase, as they do not cause significant Q waves and their T waves are already inverted.
What is the MI Treatment for STEMIs?
PCI or thrombolytics
Concave ST segment seen with ____________.
Pericarditis
What is concave ST segment most often associated with?
Pericarditis -- an inflammation of the pericardium and the myocardium immediately beneath it, but it can also be seen in STEMIs
STEMIs tend to be _________.
Transmural (they usually, though not always damage the entire thickness of the myocardium in a certain area of the heart)
What are hyperacute T waves?
Unusually tall T waves seen in earliest stages of MI
What's opposite T wave inversion?
Upright T wave
A transition in __ or __ is called counterclockwise.
V1 or V2
A transition in __ or __ is called clockwise.
V5 or V6
What is sometimes the first clue that the patient has had an MI?
Ventricular fibrillation
Aspirin
medication that reduces pain and fever. Helps decrease platelets aggregation (clumping of platelets)
Counter clockwise
move in opposite direction than clock's hand.
EKG has baseline ST segments, significant Q waves and upright T waves in I, aVL, and V1 to V6. What is the diagnosis?
old extensive anterior MI
EKG has the only tall R wave remaining. ST segments would be at baseline and the T wave would be inverted. What is the diagnosis?
old posterior MI
What is acute pericarditis? What occur son the EKG?
the pericardium and the myocardium just beneath it are inflamed, causing repolarization abnormalities that present as concave St segment elevation
Chest pain location
under sterum, midchest, entire upper chest midchest, neck, and jaw midchest, shoulder and inside arms, more left upper abdomen, often mistaken for indigestion chest, plus neck, jaw, inside arms. Jaw from ear to ear, both sides upper neck, and lower center neck shoulder usually left, inside arms to waist, plus opposite arm, inside to elbow. Between shoulder blades.
What are the symptoms of MI?
*Patients may have any or all of these* -Chest pain, pressure, or discomfort that can radiate to the arms, jaw, neck, back -Pallor -Nauseau -Feeling of impending doom -Shortness of breath -Lightheadedness of dizziness
2) State the differences between a STEMI and a NSTEMI.
-A STEMI causes ST elevation, T wave inversion, and significant Q waves develop on the EKG -The NSTEMI does not cause development of significant Q waves
What is PCI (percutaneous coronary intervention)?
-A ballon procedure to open the blocked coronary artery -A wire mesh called a stent may then be placed at the site of the former blockage to serve as. Sort of scaffold to keep the artery open
What is the goal of a PCI?
-A door to ballon time of 90 minutes, meaning the STEMI impatient should be having the PCI procedure within 90 minutes of arriving at the hospital
Typically, how is early repolarization diagnosed?
-A series of EKGs would reveal the typical evolutionary changes if an MI were present, and they would remain unchanged if early repolarization were present -
What is great help in differentiating repolarization and MI?
-Age and presentation of the patient -i.e. A 20 year old black male with no cardiac complaints who has mild ST elevation probably has early repolarization -VS a 65 year old male with chest pain and ST elevation is more likely to have an MI in progress -Only by examining the patient Can the definitive diagnosis of early repolarization versus MI be made
How is the age of an MI determined?
-An MI that has ST segment is acute (one to two days old or less) -An MI with significant Q waves, baseline (or almost back to baseline) ST segments, and inverted T waves is of age indeterminate (several days old, up to a year in some cases). Some authorities call this a recent MI. -The MI with significant Q waves, baseline ST segments, and upright T waves is old (weeks to years old).
How does the ST elevation of pericarditis differ from that of an MI?
-An MI usually produces convex ST elevation, whereas pericarditis produces concave elevation -These are often referred to as the smiley-face and frowny-face ST segments -The smiley face is the concave ST elevation -The frowns face is convex
What are treatments that NSTEMI patients may receive?
-Antiplatelet or anticoagulant medications o thing he blood and prevent recurrences of the MI -They may be started on beta blockers to decrease the heart's workload -They will eventually have an Angiogram done to determine the location of the coronary artery blockage (Further Treatment can then be determined based on the angiogram results)
Why is the treatment of STEMIS more emergent than the treatment of NSTEMIs?
-Because the coronary artery blockage is complete, and myocardial necrosis is a certainty without treatment
How does the heart try to compensate after damage of a heart attack?
-Because the heart cant pump out as much blood as before, it compensates by pumping more often--this is an attempt to maintain cardiac output -Therefore, sinus tachycardia is common following an MI
What does injured cardiac tissue look like?
-Becomes bluish in appearance
When myocardial tissue is ischemic, what happens to it in appearance?
-Becomes pale and whitish in appearance
What is an occlusion?
-Blockage of a coronary artery
What are the EKG complications of an inferior MI?
-Bradycardias, first-degree AV block, Wenckebach, third-degree AV block wth narrow ARS, accelerated junctional rhythm, junctional bradycardia, AIVR, ventricular arrhythmias, V-fib in early horus
Where can the pain of the MIs extend to?
-Can extend into the jaw, the right chest, the neck, the back, or down the arm (usually the left arm) -Can even represent as a stubborn toothache
What can decreased diastolic filling time lead to?
-Cardiogenic shock, a type of shock caused by catastrophic heart failure
What should be "looked for" in the blood of suspected MI patients?
-Certain enzymes (troponin and CPK in particular) are released into the blood stream by damaged myocardial cells during an MI and can be noted on lab values
What is an MI? What is it caused by?
-Death of myocardial tissue -Caused by occlusion of a coronary artery
If the location of the STEMI is extensive anterior (sometimes called extensive anterior-lateral), what are the EKG changes and what use the correlating coronary artery?
-EKG CHANGES: Indicative changes in I, aVL, V1 to V6 Reciprocal changes in II, III, aVF -CORONARY ARTERY: LAD or left main
EKG has widespread ST depression and T wave inversions. What is the diagnosis?
Acute NSTEMI
EKG has ST elevation in V2 to V4 and reciprocal ST depression in Leads II, III, and aVF. What is the diagnosis?
Acute anterior MI
EKG has significant Q waves and ST elevation in I, aVL, and V1 to V6 along with the reciprocal ST depression in II, III, and aVF. What is the diagnosis?
Acute extensive anterior MI
EKG has ST elevation in Leads I, aVL, and V5 to V6. Also reciprocal ST depression in Leads II, III, and aVF. What is the diagnosis?
Acute lateral wall MI
EKG has tall R wave in V1 to V2 along with ST segment depression and an upright T wave. What is the diagnosis?
Acute posterior wall MI
EKG has more normal ST segments, significant Q waves and inverted T waves in V1 to V2. What is the diagnosis?
Age indeterminate anteroseptal MI
EKG has more normal ST segments along with significant Q waves and inverted T waves in Leads II, III, and aVF. What is the diagnosis?
Age indeterminate inferior MI
EKG has more normal ST segments along with significant Q waves and inverted T waves in I, aVL, and V5 to V6. What is the diagnosis?
Age indeterminate lateral MI
EKG has more normal ST segments, a tall R wave and an upright T wave. What is the diagnosis?
Age indeterminate posterior MI
What's the opposite of a Q wave?
An R wave
ST elevation in Leads II, III, and aVF indicates ______.
An inferior MI
Posterior MIs almost always accompany __________.
An inferior MI, so always look for a posterior MI when an inferior MI is present
In lead V3, which wall of the heart does it look at?
Anterior
In lead V4, which wall of the heart does it look at?
Anterior
In lead V2, which wall of the heart does it look at?
Anterior (posterior if mirror image)
After the tissue becomes ischemic, what happens next?
As the coronary occlusion continues, the once ischemic tissue becomes injured by the continued lack of perfusion
Females in general are more likely to have _____ when they infarct.
Atypical symptoms
Describe the St elevation of pericarditis.
Because pericarditis does not involve coronary artery blockage, the ST elevation will not be limited to Leads overlying areas fed by a certain coronary artery--it will be widespread throughout many leads
NSTEMIS are treated less aggressively early on. Why is that?
Because these MIs do still allow some coronary artery flow distal to (beyond) the narrowed area
Why are indicative changes named 'indicative'?
Because they indicate in which leads the MI is located
___________ are notorious for have "silent MIs".
Diabetics
What are indicative changes?
EKG changes that indicate the presence of an MI
It is not always possible to distinguished _________.
Early repolarization from an MI based on only a single EKG
Actual death of tissue is the need of a process that begins with _____ and ______.
Ischemia and injury
ST depression implies ____ or _____.
Ischemia or reciprocal changes opposite the area of infarct
1) List the three I's of infarction.
Ischemia, injury, and infarction
If Mr. Milner, a 69-year-old man with ah story of chest pain, arrives in your ER with newly inverted T waves in leads II, III, and aVF, what do you suspect is happening?
It is likely he has new ischemia in the inferior wall of the left ventricle
In Lead V6, which wall of the heart does it look at?
Lateral
In lead I, which wall of the heart does it look at?
Lateral
In lead V5, which wall of the heart does it look at?
Lateral
In lead aVL, which wall of the heart does it look at?
Lateral
Where is early repolarization most evident (the leads)?
Leads V2 to V4
The positive pole of Leads II, III, and aVF sit on the _______.
Left leg
Each of the ______ can be "seen" by our EKG electrodes.
Left ventricular walls
NSTEMIS are treated _____________ early on.
Less aggressively early on.
EKG has normal ST segments, significant Q waves and T wave inversions in V2 to V4. What is the diagnosis?
MI is age indetermiante
EKG has only significant Q wave remaining, ST segment would be back at baseline and the T wave would be upright. What is the diagnosis?
MI is old
What is the MI treatment for all suspected MIs?
MONA -morphine -oxygen -nitroglycerin -aspirin
What is the MI treatment for NSTEMIs?
Medications such a s beta blockers, anticoagulants or anti-platelet agents, eventual angiogram
If nitroglycerin is ineffective in suspected MI patients, what can be done to help the patient?
Morphine, a narcotic that has cardiac benefits (it modestly decreases return of venous blood to the heart, helping treat/prevent heart failure) can be used to relive MI pain
What is a significant Q wave?
Must be at least 0.04 seconds wide or one-third the size of the R wave
ST segment elevation implies ___________.
Myocardial injury
What can abnormal T waves imply
Myocardial ischemia
A significant Q wave implies _______.
Myocardial necrosis
________ is damaged during an MI.
Myocardium
Which MI typically does less damage?
NSTEMIs (non-ST elevation MIs)
What happens to the R waves as they travel through the leads?
R waves progress from very small in V1 to very large in V6
What is the R wave progression?
R waves tart out small in v1 and get larger as they move toward V6. Transition zone V3 to V4
What is age indeterminate also called?
Recent MI
In the area electrically opposite the infarct area are _______________.
Reciprocal changes (i.e. ST depression)
5) Reciprocal changes are seen in which area of the heart?
Reciprocal changes are seen int he area electrically opposite the damaged area
Ischemia and injury are ___________.
Reversible
On occasion, an inferior MI will be accompanied by a ___________.
Right ventricular (RV) infarction
ST elevation in Leads V3R to V4R. What is the diagnosis?
Right-side EKG
Why are RV infarctions not detectable by routine EKG?
Routine 12-lead EKG which looks at the left ventricle
What's the opposite ST elevation?
ST depression
ST depression is seen only when there is ________ in the indicative leads.
ST elevation
Convex (coved) ST segment implies _________.
STEMI
The treatment of STEMIS or NSTEMIS is more emergent?
STEMIS
What are the EKG complications of an anteroseptal?
Same as anterior but with increased chance of v-fib occurring late (greater than 48 hours after infarct)
In lead V1, which wall of the heart does it look at?
Septal (posterior if mirror image)
If there is significant ST segment elevation in the indicative leads, there should be ________________.
Significant ST depression in the reciprocal leads
Because the myocardium is damaged during an MI, it is not unusual for ______________ to occur.
Some degree of heart failure (decreased pumping efficiency)
What is evolution?
The EKG changes over the course of a STEMI
Acute Anteroseptal MI
The ST elevation in Leads V1 to V2 (V1 a septal lead and V2 an anterior lead) The combination of V1 plus any anterior lead.
What is the posterior wall of the left ventricle? What artery feeds it?
The back wall--fed by the right coronary artery
What is the inferior wall of the left ventricle? What artery feeds it?
The bottom wall--fed by the right coronary artery
10) Which coronary artery supplies the lateral wall of the left ventricle?
The circumflex coronary artery supplies the lateral wall of the left ventricle
4) Name the three normal indicative changes of an MI.
The normal indicative changes of an MI are ST elevation, significant Q waves, and T wave inversions
What is the anterior wall of the left ventricle? What artery feeds it?
The front wall--fed by the left anterior descending coronary artery
9) The kind of MI that can be diagnosed by inverting the EKG and looking at leads V1 and V2 from behind is the ___________.
The kind of MI that can be diagnosed by inverting (turning over) the EKG and looking at leads V1 and V2 from behind is the posterior MI
What is the lateral wall of the left ventricle? What artery feeds it?
The left side wall of the heart--fed by the circumflex coronary artery
Besides nitroglycerin, oxygen, and possibly morphine, what is also done to help MI patients and why?
They are given an aspirin to chew (yes, chew) to help decrease platelet aggregation (clumping of platelets). -Platelet aggregation forms clots -Preventing this aggregation helps prevent any blood clot that is already int he coronary artery from growing larger -These media re given only if there are no contraindications (i.e. A patient with bleeding ulcers I n his or her stomach may not be given the aspiring, because it would increase the chance of bleeding)
What do an MI and pericarditis have in common--symptom wise?
They both cause chest pain and as a result, it is important to differentiate between the two
Where do leads I, aVL, and V5 and V6 sit and what do they view?
They sit on the heart's left side and look at the lateral wall
If NSTEMIs are not treated, what will typically occur?
They will typically go on to have a STEMI within a few months if treatment for the coronary artery blockage is not provided
What s the only way to diagnose a posterior MI?
To look for changes opposite those that would be seen with an anterior
What symptoms should be paid very careful attention to in females?
When a female, especially one who is postmenopausal complains of fatigue, shortness of breath, or other vague symptoms -It could be her version of chest pain--what cardiologists call women's angina equivalent)
How is a right-side EKG done?
With the limb leads in their normal places, but with the precordial leads placed on the right side of the chest instead of the left.
EKG has ST elevation in Leads II, III, and aVF and reciprocal ST segment depression in Leads I, aVL, and V1 to V6. What is the diagnosis?
acute inferior MI
EKG has more normal ST segments along with significant Q waves and T wave inversion. What is the diagnosis?
age indeterminate extensive anterior MI