Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Chest pain > ACS ECG > Flashcards

ACS ECG Flashcards

(110 cards)

Start Studying
1
Q

What is the earliest electrocardiographic finding in STEMI?

A

The hyperacute T wave

A tall and peaked structure that can appear within minutes of the interruption of blood flow and initiation of acute infarction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the structure of the hyperacute T wave in STEMI?

A

Broad-based and asymmetrical

The ST segment can be elevated at the junction between the QRS complex and ST segment.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does the hyperacute T wave progress to in typical STEMI?

A

ST segment elevation

This progression occurs as the infarction advances.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Which conditions can also present with tall T waves besides acute ischemia?

A
  • Hyperkalemia
  • Benign early repolarization (BER)
  • Left ventricular hypertrophy (LVH)
  • Left bundle branch block (LBBB)
  • Acute pericarditis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the morphologic variations of ST segment elevation in STEMI?

A
  • Flat
  • Convex
  • Domed
  • Tombstoned
  • Horizontal or oblique
  • Concave or scooped
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How is ST segment elevation measured on an electrocardiogram?

A

In millimeters

One block on the electrocardiographic tracing is equivalent to 1 mm in height.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the usual baseline considered for measuring ST segment elevation?

A

The TP segment

Some advocate using the terminal point of the PR segment.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is benign early repolarization (BER)?

A

A common finding in young males with ST segment elevation

It is usually 1 mm or more in men and 1 mm or less in women.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How can one differentiate normal ST segment elevation from pathologic ST segment elevation of STEMI?

A

ST segment elevation in STEMI is a dynamic phenomenon

ECGs recorded sequentially should show fluctuation in the degree of ST segment deviation.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does ST segment depression generally represent in patients with chest pain?

A

Subendocardial ischemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the typical contour of ischemic ST segment depression?

A

Horizontal or downsloping

An upsloping contour may be seen but is less frequently associated with ischemia.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which clinical conditions can present with ST segment depression?

A
  • Myocardial ischemia or infarction
  • Repolarization abnormality of left ventricular hypertrophy
  • Bundle branch block
  • Ventricular paced rhythm (VPR)
  • Digoxin effect
  • Hyperkalemia
  • Hypokalemia
  • Pulmonary embolism (PE)
  • Intracranial hemorrhage
  • Myocarditis
  • Rate-related ST segment depression
  • Postcardioversion of tachydysrhythmias
  • Pneumothorax
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

In what leads will ST segment depression appear during transmural posterior wall infarction?

A

Right to mid precordial leads

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What type of myocardial infarction is associated with ST segment depression?

A

NSTEMI

ST segment depression can also precede ST segment elevation in STEMI

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does ST segment depression in leads V1 to V3 indicate in the context of posterior MI?

A

It reflects a mirror image of ST segment elevation from posterior MI

This occurs when there is ST segment depression in the right- to mid-precordial leads

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the significance of reciprocal ST segment depression?

A

It indicates changes seen in leads opposite to ST segment elevation

For example, in posterior MI, depression in V1 to V3 reflects elevation in posterior leads V8 and V9

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Which lead is best for identifying reciprocal ST segment depression in inferior MI?

A

Lead aVL

This lead is 150 degrees removed from lead III

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

In anterior STEMI, which inferior leads may show reciprocal ST segment depression?

A

II, III, or aVF

These leads can show reciprocal changes in the context of ST segment elevation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

True or False: Reciprocal changes in STEMI increase the specificity and positive predictive value of the ECG.

A

True

They coincide with larger infarctions and increased risk of adverse cardiovascular events

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What does T wave inversion typically suggest in the context of ACS?

A

Chronic ischemic change or ACS

T wave inversions are nonspecific but significant in the right clinical context

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Which leads typically have upright T waves?

A

I, II, and V3 to V6

T waves are normally inverted in lead aVR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What characterizes the T wave inversions of ACS?

A

They are classically narrow and symmetrical

The preceding ST segment is typically isoelectric

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is Wellens syndrome characterized by?

A

Deep symmetrical T wave inversions (type I) or biphasic T wave changes (type II)

These changes are suggestive of myocardial ischemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What additional electrocardiographic features are associated with Wellens syndrome?

A

Isoelectric or minimally elevated ST segments and lack of precordial Q waves

This can occur in both anginal and pain-free states

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What happens to T waves in MI without culprit artery reperfusion?
T waves may invert as ST segments return to baseline ## Footnote The inversion may not be particularly deep
26
What does pseudonormalization of the T wave indicate?
An apparently normal T wave replacing a previously inverted T wave during acute ischemia ## Footnote This can be a sign of acute ischemia
27
What do pathologic Q waves represent?
Irreversible myocardial necrosis ## Footnote They may develop within the first hour of infarction or at 8 to 12 hours
28
True or False: Q waves can persist after MI as markers of previous infarction.
True ## Footnote They may also disappear over time, regardless of reperfusion status
29
Differential Diagnosis of Electrocardiographic ST Segment Elevation in the Adult Chest Pain Patient
Acute myocardial infarction Acute pericarditis Left ventricular hypertrophy Left ventricular aneurysm Ventricular paced rhythm Benign early repolarization Normal variant Osborn wave of hypothermia Hyperkalemia Brugada syndrome Pulmonary embolism Acute cerebral hemorrhage Prinzmetal angina Postelectrical cardioversion
30
What leads show changes in anterior infarctions?
Changes are primarily evidenced by leads V1 to V4 ## Footnote Anterior infarctions can also show reciprocal ST segment depression in leads III and aVF
31
Which leads indicate septal involvement in an AMI?
Changes are reflected by leads V1 and V2 ## Footnote Septal involvement may indicate a specific region of myocardial damage
32
What leads are involved in anterolateral myocardial infarction?
Involvement extends to leads V5, V6, I, and aVL ## Footnote Anterolateral MI indicates extension beyond the anterior leads
33
What artery supplies the anterior wall of the heart?
The left anterior descending artery ## Footnote This artery is crucial for blood supply to the anterior wall
34
What does isolated occlusion of the diagonal branch of the left anterior descending artery display?
Similar findings to left anterior descending artery occlusion, but of smaller amplitude ## Footnote Findings include ST segment elevation in leads V2 and V3, and possibly leads V1 and V3
35
What is a high-risk presentation associated with anterior or anterolateral STEMI?
Left main coronary artery occlusion ## Footnote Identifying this high-risk STEMI subtype helps in adjusting therapy
36
What should ST segment elevation in lead aVR prompt consideration of?
Occlusion of the left main coronary artery ## Footnote ST segment elevation in lead aVR (>0.5 mV) is sensitive and specific for left main coronary artery disease
37
What does ST segment elevation in lead aVR and V1 indicate?
Greater elevation in aVR favors left main disease; greater in V1 indicates left anterior descending artery occlusion ## Footnote This helps differentiate the type of occlusion present
38
What does the de Winter ECG pattern suggest?
It is associated with acute coronary syndrome ## Footnote Findings include prominent T waves with J point depression and ST segment elevation in lead aVR
39
What are the characteristics of de Winter syndrome?
Electrocardiographic findings include ST segment depression in precordial leads and ST segment elevation in lead aVR ## Footnote This syndrome is linked to proximal left anterior descending artery lesions
40
What leads indicate high lateral infarctions?
Leads I and aVL ## Footnote High lateral infarctions suggest occlusion of the left circumflex coronary artery or first diagonal
41
What is a potential complication of subtle ECG findings in leads I and aVL?
They may be easy to overlook despite indicating significant issues ## Footnote ST segment elevation in these leads can be accompanied by reciprocal ST segment depression in leads III, aVF, and V1
42
Location Leads ST Segment Anterior wall STEMI V1–V4 Elevation Lateral wall STEMI I, aVL, V5, V6 Elevation Inferior wall STEMI II, III, aVF Elevation Right ventr. wall AMI V4R Elevation Posterior wall AMI V8, V9 Elevation V1–V3 Depression
43
44
What leads are characteristic of inferior infarctions?
Limb leads II, III, and aVF ## Footnote These leads show morphologic changes indicative of inferior infarctions.
45
Which artery serves the inferior wall of the heart in about 90% of cases?
Right coronary artery ## Footnote This is referred to as right dominant circulation.
46
What is frequently seen in lead aVL in the context of inferior STEMI?
Reciprocal ST segment depression ## Footnote This can also be seen in lead I or both.
47
What does ST segment elevation in lead III greater than in lead II suggest?
Right coronary artery occlusion ## Footnote This finding is 90% sensitive and 71% specific.
48
What might ST segment elevation in lead V1 indicate in the presence of inferior MI?
Concomitant right ventricular infarction ## Footnote This is suggested when ST segment elevation in lead III is greater than in lead II.
49
How does coexistent reciprocal change with inferior STEMI affect infarct size?
Associated with larger infarct size and increased mortality ## Footnote This indicates a more severe clinical picture.
50
What may be occult on a 12-lead ECG in inferior ST segment elevation?
Occlusion of the left circumflex artery ## Footnote This may not show expected changes in lead III compared to lead II.
51
What percentage of all AMIs do posterior infarctions contribute to?
15% to 20% ## Footnote These are usually seen with inferior or inferolateral infarctions.
52
In what percentage of AMI cases do posterior infarctions occur in isolation?
Approximately 5% ## Footnote These cases demonstrate elevated ST segments only in accessory leads.
53
What findings in leads V1 to V3 suggest acute posterior myocardial infarction?
* Horizontal ST segment depression * Upright T wave * Tall, wide R wave * R wave amplitude–to–S wave amplitude ratio greater than 1
54
What increases the diagnostic accuracy of the 12-lead ECG for acute posterior MI?
Combination of horizontal ST segment depression with an upright T wave ## Footnote This combination provides better diagnostic clarity.
55
What might patients with inferior MI and ST segment changes in leads V1 to V3 experience?
Larger infarction zones, lower resultant ejection fractions, and higher rates of cardiovascular morbidity and mortality ## Footnote This indicates a worse prognosis.
56
What is suggested by the tall R wave in leads V1 and V2 during posterior infarction?
It is a mirror image of a posterior Q wave ## Footnote Its emergence may be delayed in posterior infarction.
57
What is the commonest artery involved in right ventricular infarctions?
Right coronary artery ## Footnote This type of infarction is rarely isolated.
58
What clinical features are associated with right ventricular infarction?
* Elevated jugular venous pressure * Hypotension ## Footnote These features may also suggest pericardial tamponade.
59
What initial therapy should be considered for right ventricular infarction?
Volume loading and avoidance of vasodilators ## Footnote This approach helps manage blood pressure effectively.
60
What does ST segment elevation in lead V1 during inferior STEMI suggest?
Right ventricular infarction ## Footnote Lead V1 is oriented towards the right ventricle.
61
What is the best means to diagnose right ventricular infarction with the ECG?
Application of right-sided precordial leads ## Footnote These leads provide a mirror image of the left precordial leads.
62
Which right-sided lead has the highest sensitivity for right ventricular infarction?
Lead V4R ## Footnote This lead is critical for accurate diagnosis.
63
What is a possible outcome for patients with inferior STEMI and concomitant right ventricular infarction?
Larger infarcts and higher mortality rates ## Footnote This indicates a more severe clinical scenario.
64
What are two conditions that can feature ST segment elevation mimicking infarction?
* LBBB * LVH
65
What does benign early repolarization (BER) imply regarding ACS or CAD?
Does not imply or exclude ACS or CAD
66
What are the electrocardiographic characteristics of benign early repolarization (BER)?
* ST segment elevation * Upward concavity of the initial ST segment * Notching of the terminal QRS complex at the J point * Symmetric concordant T waves of large amplitude * Diffuse ST segment elevation * Relative temporal stability over the short term
67
What is the typical J point elevation in benign early repolarization?
Usually less than 3.5 mm
68
In which leads is maximal ST segment elevation in benign early repolarization typically seen?
Leads V2 to V5
69
What is a characteristic feature of ST segment elevation in pericarditis?
Concave ST segments with an initial upsloping contour
70
What is the height of the ST segments typically seen in pericarditis?
Usually less than 5 mm
71
What is PR segment depression associated with in pericarditis?
An insensitive yet specific electrocardiographic finding
72
How can you distinguish acute anterior MI from left ventricular aneurysm using T wave and QRS complex amplitude?
If the ratio of T wave amplitude to QRS complex exceeds 0.36, it likely reflects STEMI; if less than 0.36, it likely indicates LVA
73
What effect does LBBB have on the ECG's ability to indicate ACS?
Reduces the ability
74
What does a new LBBB in a clinical situation suggest?
May indicate ACS
75
In which leads does LBBB typically show ST segment elevation and tall T waves mimicking anterior STEMI?
Leads V1 to V3
76
What is the 'rule of appropriate discordance' related to LBBB?
The ST segment and T wave vectors are expectedly discordant to the major vector of the QRS complex
77
What should be distinguished in a patient with LBBB presenting with AMI?
Normal findings in LBBB and presentation of AMI
78
What are the three independent electrocardiographic predictors of AMI in the presence of LBBB identified by Sgarbossa and colleagues?
* ST segment elevation of at least 1 mm concordant with the QRS complex * ST segment depression of at least 1 mm in lead V1, V2, or V3 * ST segment elevation of at least 5 mm discordant with the QRS complex ## Footnote These predictors help in diagnosing acute myocardial infarction (AMI) when LBBB is present.
79
What weighted scores were assigned to the predictors of AMI in the presence of LBBB?
* ST segment elevation concordant with QRS complex: 5 * ST segment depression in V1, V2, or V3: 3 * ST segment elevation discordant with QRS complex: 2 ## Footnote A specificity of 90% requires a score of at least 3 for accurate diagnosis.
80
What does a score of at least 3 indicate in the context of diagnosing AMI with LBBB?
A specificity of 90% for accurate diagnosis ## Footnote This means that further testing is recommended if only discordant ST segment elevation of 5 mm or more is present without the other two criteria.
81
What is the modified Sgarbossa criteria?
It omits the third component (discordant ST segment elevation ≥ 5 mm) and substitutes the ratio of discordant ST segment deviation to S wave amplitude ## Footnote Excessive discordance, defined by an ST/S ratio of greater than 0.25, is considered diagnostic of AMI.
82
What is the definition of excessive discordance in the modified Sgarbossa criteria?
An ST/S ratio greater than 0.25 ## Footnote This indicates a high likelihood of acute myocardial infarction.
83
What should be considered a high-risk presentation in patients with LBBB?
A newly noted LBBB occurring in a patient with a compelling presentation for AMI ## Footnote In such cases, AMI is likely.
84
How do ventricular paced rhythms (VPRs) affect the diagnosis of AMI?
VPRs can mimic and mask the manifestations of AMI ## Footnote They create a wide QRS complex with a pseudo-LBBB pattern.
85
What are the three criteria for detecting AMI in the presence of VPR?
* ST segment elevation of at least 5 mm discordant with the QRS complex * ST segment elevation of at least 1 mm concordant with the QRS complex * ST segment depression of at least 1 mm in lead V1, V2, or V3 ## Footnote These criteria are similar to those for LBBB.
86
What does left ventricular hypertrophy (LVH) mimic on the ECG?
It may mimic or obscure acute coronary syndrome (ACS) ## Footnote LVH features prominent left-sided forces but typically does not extend beyond leads V1 and V2.
87
What is a strain pattern in LVH?
Evidence of ST segment depression and asymmetrically inverted T waves in the left precordial leads ## Footnote This pattern can reassure that certain changes are due to LVH rather than AMI.
88
What is Takotsubo cardiomyopathy also known as?
Left apical ballooning or broken heart syndrome ## Footnote It is characterized by ST segment elevation or deep T wave inversions without obstructive coronary artery disease.
89
What is the prognosis for Takotsubo cardiomyopathy?
Excellent, with recovery of normal wall motion typically within 1 month or less ## Footnote It is often associated with intense emotional stress.
90
What does NSTEMI stand for?
Non-ST segment elevation myocardial infarction ## Footnote It replaced the term 'non-Q wave MI' previously referred to as 'subendocardial infarction.'
91
What are the typical electrocardiographic manifestations of NSTEMI?
* ST segment depression * T wave inversion (which may be deep and symmetrical) * Nonspecific ST segment or T wave abnormalities ## Footnote Absence of STEMI does not necessarily indicate better outcomes.
92
What is the in-hospital mortality rate for patients with ST segment depression on the initial ECG?
Similar to that of patients with ST segment elevation or LBBB (15%-16%) ## Footnote This highlights the seriousness of NSTEMI despite the absence of ST segment elevation.
93
What may ST segment depression in leads V1 to V3 or V4 indicate?
True posterior infarction on the 12-lead ECG ## Footnote This can signal the need for emergent revascularization even without ST segment elevation.
94
What is the purpose of additional lead ECGs in diagnosing AMI?
They increase sensitivity by evaluating regions of the heart prone to electrical silence.
95
What constitutes a 15-lead ECG?
It includes the standard 12-lead ECG plus posterior (leads V7 to V9) and right ventricular (V4R) electrodes.
96
Where are the posterior leads V8 and V9 placed?
Under the tip of the left scapula and at the left paraspinal area at the same level as leads V4 to V6.
97
What is considered ST elevation in posterior leads?
Any elevation in these leads, even if it is not 1 mm.
98
What enhances electrocardiographic imaging of the right ventricle?
The use of right-sided chest leads V1R to V6R.
99
Which right precordial lead has the highest sensitivity for right ventricular infarction?
V4R.
100
Does the 15-lead ECG affect the rate of AMI diagnosis in all ED patients?
No, it does not appear to affect the rate of AMI diagnosis, use of reperfusion therapy, or outcomes.
101
By how much did the 15-lead ECG increase sensitivity of ACS detection in high-risk patients?
By 12%.
102
What are some applications for additional lead ECGs?
* ST segment changes in leads V1 to V3 * Equivocal ST segment elevation in limb leads * All inferior STEMI * Hypotension in the setting of ACS
103
What is the purpose of monitoring ST segment trends and using serial ECGs?
They overcome the limitations of a single snapshot of a 12-lead ECG.
104
What is the diagnostic benefit of increased electrocardiographic surveillance?
It significantly increases sensitivity and specificity for detection of STEMI and ACS.
105
How often should ST segment trends be measured for diagnostic benefit?
Every 20 seconds for at least the first hour.
106
What percentage of patients ultimately diagnosed with STEMI have a nondiagnostic initial ECG?
Approximately 50%.
107
What percentage of patients diagnosed with AMI had nondiagnostic ECGs earlier in their course?
About 20%.
108
What is the sensitivity and specificity of a single ECG for AMI?
Sensitivity is approximately 60% and specificity is 90%.
109
What can only exclude AMI in patients being evaluated for ACS?
Serial electrocardiography combined with serial cardiac marker determinations.
110
Fill in the blank: The initial ECG is nondiagnostic in approximately ______ of patients in the ED diagnosed with STEMI.
50%

Chest pain (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions