170 Questions
Which condition can mimic ST segment elevation of infarction on an ECG?
Left bundle branch block (LBBB)
What is a normal electrocardiographic variant that does not imply or exclude ACS or CAD?
Benign early repolarization (BER)
What is the usual J point elevation in benign early repolarization (BER)?
$< 3.5$ mm
What is a characteristic of the ST segment in benign early repolarization (BER)?
Upward concavity of the initial portion
In acute pericarditis, the ST segments are typically:
Concave, with an initial upsloping contour
Which leads usually show ST segment elevation in pericarditis?
All leads except for aVR
What electrocardiographic finding is associated with pericarditis and is best seen in the inferior leads and lead V6?
PR segment depression
Why is the term 'myopericarditis' considered more appropriate than 'pericarditis'?
ST segment changes result from epicardial irritation
What is the characteristic ST segment morphology that strongly suggests STEMI on an ECG?
Convex or domed
In pericarditis, which electrocardiographic finding is both insensitive and specific, and is typically best seen in the inferior leads and lead V6?
PR segment depression
What is the term used to describe a more appropriate diagnosis than 'pericarditis' due to the electrical silence of the pericardium?
Myopericarditis
Which leads usually show ST segment elevation in benign early repolarization (BER)?
$V2$ to $V5$
Which condition can mimic ST segment elevation of infarction on an ECG?
Left bundle branch block (LBBB)
What is a characteristic of the ST segment in benign early repolarization (BER)?
ST segment elevation
In acute pericarditis, the ST segments are typically:
Elevated in most leads
What electrocardiographic finding is associated with pericarditis and is best seen in the inferior leads and lead V6?
$ ext{T wave inversion}$
Which of the following may help distinguish acute anterior MI from LVA?
Ratio of T wave amplitude to QRS complex amplitude
In a clinical situation strongly suggestive of ACS, a new LBBB may indicate:
ACS
Where are ST segment elevation and tall, vaulted, upright T waves mimicking those seen in anterior STEMI often observed?
Right precordial leads (leads V1 to V3)
What is a confounding pattern that reduces the ECG’s ability to indicate ACS?
LBBB
What may help distinguish acute anterior MI from LVA?
The ratio of the amplitude of the T wave to the QRS complex
Where are ST segment elevation and tall, vaulted, upright T waves mimicking those seen in anterior STEMI often observed?
Right precordial leads (leads V1 to V3)
What is a confounding pattern that reduces the ECG’s ability to indicate ACS?
LBBB
In a clinical situation strongly suggestive of ACS, what may indicate ACS when considering LBBB?
A new LBBB
What is the specificity score required for accuracy in diagnosing AMI in the presence of LBBB, based on the identified electrocardiographic predictors?
Score of at least 3
Which electrocardiographic finding is recommended to be further tested if it features only discordant ST segment elevation of 5 mm or more but neither of the other two criteria?
ST segment elevation discordant with the QRS complex
What weighted score is assigned to ST segment depression of at least 1 mm in lead V1, V2, or V3 as an electrocardiographic predictor of AMI in the presence of LBBB?
3
What is the specificity score required for accuracy in diagnosing AMI in the presence of LBBB, based on the identified electrocardiographic predictors?
90%
Which electrocardiographic finding is recommended to be further tested if it features only discordant ST segment elevation of 5 mm or more but neither of the other two criteria?
None of the above
What weighted score is assigned to ST segment elevation of at least 1 mm that is concordant with the QRS complex as an electrocardiographic predictor of AMI in the presence of LBBB?
5
What is considered diagnostic of acute myocardial infarction (AMI) in the modified Sgarbossa criteria?
Discordant ST/S ratio greater than 0.25
What should be considered a high-risk presentation when occurring in a patient with a compelling presentation for AMI?
A newly noted LBBB
What can mimic and mask the manifestations of AMI, creating a wide QRS complex with a pseudo-LBBB pattern?
Ventricular paced rhythms (VPRs) originating in the right ventricular apex
What should be applied when the ECG is not diagnostic for acute infarction as noted by the Sgarbossa criteria?
Diagnostic adjuncts to the history and physical examination
What is considered diagnostic of acute myocardial infarction (AMI) in the modified Sgarbossa criteria?
ST/S ratio greater than 0.25
In a patient with a compelling presentation for AMI, what should be considered a high-risk presentation?
A newly noted LBBB
What can mimic and mask the manifestations of AMI, creating a wide QRS complex with a pseudo-LBBB pattern?
Ventricular paced rhythms originating in the right ventricular apex
What should be applied when the ECG is not diagnostic for acute infarction as noted by the Sgarbossa criteria?
Diagnostic adjuncts to the history and physical examination
What is a confounding pattern that reduces the ECG’s ability to indicate ACS?
Ventricular paced rhythm
What is a characteristic of the ST segment in left ventricular hypertrophy (LVH) that may mimic or obscure ACS on the ECG?
ST segment depression of at least 1 mm in lead V1, V2, or V3
Where are ST segment elevation and tall, vaulted, upright T waves mimicking those seen in anterior STEMI often observed?
Lead V5 and V6
What electrocardiographic finding is associated with pericarditis and is best seen in the inferior leads and lead V6?
PR segment depression
What electrocardiographic finding is associated with Takotsubo cardiomyopathy?
ST segment elevation and deep T wave inversions
Which condition is characterized by a strain pattern in the left precordial leads and a mirror image pattern in the right precordial leads?
Left ventricular hypertrophy (LVH)
What is a characteristic feature of Takotsubo cardiomyopathy on ventriculography or echocardiography?
Ballooning of the left ventricular apex
What is characteristic of the changes in LVH over time?
Static
Which electrocardiographic finding is associated with Takotsubo cardiomyopathy?
ST segment elevation and deep T wave inversions
What is a characteristic feature of Takotsubo cardiomyopathy on ventriculography or echocardiography?
Ballooning of the left ventricular apex
What is a confounding pattern that reduces the ECG’s ability to indicate ACS?
Tall, vaulted, upright T waves
What is a characteristic of the changes in LVH over time?
Static changes in ST segment morphology
What is a characteristic feature of the initial portion of the elevated ST segment in left ventricular hypertrophy (LVH)?
Concave morphology
Which electrocardiographic finding is associated with left ventricular hypertrophy (LVH) and may mimic or obscure acute coronary syndrome (ACS) on the ECG?
Prominent left-sided forces in V1 and V2
Which of the following is a confounding pattern that reduces the ECG’s ability to indicate ACS?
ST segment elevation discordant with QRS complex
What electrocardiographic finding may help distinguish acute anterior myocardial infarction (AMI) from left ventricular aneurysm (LVA)?
$ ext{ST segment elevation in leads II, III, and aVF}$
What electrocardiographic manifestations are associated with NSTEMI?
ST segment depression and T wave inversion
What may lead to the absence of ST segment elevation in NSTEMI?
Diseased artery not totally occluded
What is the significance of ST segment depression on the initial ECG in NSTEMI?
Similar in-hospital mortality rate as ST segment elevation or LBBB
What does ST segment depression in leads V1 to V3 or V4 in NSTEMI may indicate?
True posterior infarction on the 12-lead ECG
What electrocardiographic manifestations are associated with NSTEMI?
ST segment depression and T wave inversion
What percentage of in-hospital mortality rate is associated with patients having ST segment depression on the initial ECG?
15%–16%
What may ST segment depression in leads V1 to V3 or V4 indicate in NSTEMI?
True posterior infarction
Why does the precise terminology for NSTEMI pose difficulties?
Q waves may disappear with time and the criteria for significant Q waves vary
Which additional lead ECG application can be used for identifying ST segment changes in isolated leads or more than one?
80-lead ECG
In which setting can additional lead applications like the 18-lead and 24-lead ECG be employed?
High-risk ACS detection
Which patients may demonstrate findings consistent with AMI when additional electrocardiographic leads are applied?
Patients with classic ACS presentation
What does opinion-based recommendations suggest about the use of additional ECG leads in patients lacking significant 12-lead ECG abnormality?
They may demonstrate findings consistent with AMI
Which leads are used to enhance electrocardiographic imaging of the right ventricle in the 15-lead ECG?
Leads V1R to V6R
Where are posterior leads V8 and V9 placed in the 15-lead ECG?
Under the tip of the left scapula and at the left paraspinal area at the same level as leads V4 to V6
What is considered ST elevation in posterior leads V8 and V9?
Any elevation, even if it is not 1 mm
Which lead is considered the lead of choice to include in the 15-lead tracing for enhanced electrocardiographic imaging of the right ventricle?
Lead V4R
What is the purpose of using additional lead ECGs, such as the 15-lead ECG, in high-risk ACS patients?
To increase the sensitivity of ACS detection
Which ST segment changes are considered for identification using additional lead ECGs?
ST segment changes in leads V1 to V3, in an isolated lead or in more than one
When should additional electrocardiographic leads be employed according to opinion-based recommendations?
In patients with classic ACS presentation lacking significant 12-lead ECG abnormality
What is the limitation associated with the data on the use of additional lead ECGs for increasing the rate of STEMI diagnosis?
Limited data to indicate when additional ECG leads should be employed
Where are posterior leads V8 and V9 placed in the 15-lead ECG?
Under the tip of the left scapula and at the left paraspinal area at the same level as leads V4 to V6
Which leads are used to enhance electrocardiographic imaging of the right ventricle in the 15-lead ECG?
V1R to V6R (RV1 to RV6)
What is considered ST elevation in posterior leads V8 and V9?
Any elevation, even if it is not 1 mm
Which lead has the highest sensitivity for right ventricular infarction and is recommended to be included in the 15-lead tracing?
V4R
What is the recommended frequency for automated serial ECGs in ED patients with chest pain?
Every 20 minutes
In patients admitted with nondiagnostic initial ECGs and symptoms consistent with ACS, how long of continuous 12-lead electrocardiographic monitoring is recommended in a coronary care unit setting?
12 hours
What is defined as ST segment episodes in the context of continuous electrocardiographic monitoring?
ST segment elevation or depression > 1 mm different from baseline that endured for at least 1 minute
What is the interval for measuring ST segment trends during electrocardiographic surveillance in ED patients with chest pain?
Every 20 seconds
What is the recommended frequency for automated serial ECGs in ED patients with chest pain?
Every 20 minutes
In patients admitted with nondiagnostic initial ECGs and symptoms consistent with ACS, how long of continuous 12-lead electrocardiographic monitoring is recommended in a coronary care unit setting?
24 hours
What defines ST segment episodes in the context of continuous electrocardiographic monitoring in a coronary care unit setting?
ST segment elevation or depression > 1 mm different from baseline, enduring for at least 1 minute
How often should ST segment trends be measured during electrocardiographic surveillance in ED patients with chest pain?
Every 20 seconds for at least the first hour
What is the sensitivity of a single ECG for AMI?
60%
What percentage of patients diagnosed with STEMI have an initially nondiagnostic ECG in the ED?
50%
What can exclude AMI in patients being evaluated for ACS?
Serial electrocardiography combined with serial cardiac marker determinations
What does a single normal or nondiagnostic ECG recorded well after the onset of symptoms ensure?
Absence of ACS
What is the sensitivity of a single ECG for AMI?
Approximately 60%
What percentage of patients ultimately diagnosed with STEMI have a nondiagnostic initial ECG in the ED?
Approximately 50%
What percentage of patients ultimately diagnosed with AMI have nondiagnostic ECGs earlier in their course?
About 20%
What can exclude AMI in patients being evaluated for ACS?
Serial electrocardiography combined with serial cardiac marker determinations
What can be considered an insensitive sign of aortic dissection in ACS?
Mediastinal width
In AMI patients, what indicates a higher risk for increased mortality?
Pulmonary congestion on chest radiograph
What may suggest the chronicity of the CHF syndrome in AMI patients?
Presence of cardiomegaly with or without pulmonary edema
What may be considered an insensitive sign of aortic dissection in ACS?
Mediastinal width
In AMI patients, what does the presence of heart failure on the chest radiograph indicate?
Higher risk
What may suggest the chronicity of the CHF syndrome in AMI patients?
Heart size
What role do biochemical markers play in the diagnosis, risk stratification, and guidance of treatment of ACS?
They play a pivotal role in the diagnosis, risk stratification, and guidance of treatment of ACS
What caution is advised when a single initial serum marker level is not elevated in patients with a nondiagnostic ECG?
Caution is advised when a single initial serum marker level is not elevated
What remains the most vital portion of the diagnostic evaluation of potential ACS?
Patient's history
What type of marker to identify myocardial ischemia without myocardial necrosis is not yet available?
Sensitive and specific marker
Which serum marker confirms a presumptive diagnosis of NSTEMI in patients with a nondiagnostic ECG?
Troponin I or T
What is the caution advised when a single initial serum marker level is not elevated in patients with a nondiagnostic ECG?
A single test, in the first hours following symptom onset, is currently too insensitive to support a decision for discharge.
What remains the most vital portion of the diagnostic evaluation of potential ACS?
The patient’s history
What can be used to rule out acute coronary event occurrence in patients with symptoms consistent with unstable angina?
No marker can be used to rule out that diagnosis.
When do serum troponin levels begin to rise measurably in the serum?
2 to 3 hours after onset
How long do troponin levels remain elevated in the serum?
7 days or more
What is considered an elevated level of troponin?
Exceeding the 99th percentile in a healthy population
What is recommended for evaluating patients presenting with recent onset of symptoms regarding troponin measurements?
Serial measurements
Which biomarker is utilized by the HEART score, HEART Pathway, and EDACS-ADP pathway for evaluation of ACS?
Myocardial troponin I (TnI)
What does the biphasic rise in serum troponin levels after myocardial injury correspond to?
Early release of the free cytoplasmic proteins followed by a slower rise from muscle fiber breakdown
What is the duration of sustained release of troponins following myocardial cell injury?
5 to 7 days
Which proteins precede the release of creatine kinase-MB fraction (CK-MB) into the serum during myocardial ischemia?
Troponin I (TnI) and troponin T (TnT)
What is the recommended action for evaluating patients presenting with recent onset of symptoms regarding troponin measurements?
Perform serial measurements
What defines an elevated level of troponin?
Exceeding the 99th percentile in a healthy population
What is the sensitivity of traditional troponin assays to detect abnormal low troponin levels?
Varies among existing assays
When do serum troponin levels begin to rise measurably after onset?
As early as 2 to 3 hours after onset
Which of the following is true regarding the role of cardiac troponin in the evaluation of ACS?
It is the only cardiac marker referenced in the consensus universal definition of MI
What is the biokinetics of troponin release related to?
The location of the protein within the cell
What do myocardial troponin I (TnI) and troponin T (TnT) precede during myocardial ischemia?
Release of creatine kinase-MB fraction (CK-MB) into the serum
What defines the sustained release of troponins following myocardial cell injury?
Slow destruction of the myocardial cell contractile proteins
What is the recommended interval for measuring high-sensitivity troponin (hs-T) assay testing when combined with other appropriate clinical data?
1 to 2 hours
What do detectable serum troponin levels with a high-sensitivity troponin assay indicate?
Presence of structural heart disease and all-cause mortality
What percentage of patients at risk of 30-day major adverse cardiac event (MACE) can be identified using serial hs-T assay testing combined with other appropriate clinical data?
> 99%
What concern has been expressed by some clinicians regarding the increased utilization of high-sensitivity troponin (hs-T)?
Increased incidental finding of myocardial injury unrelated to ACS
What is the recommended protocol for patients with chest pain onset greater than 3 hours from presentation?
1-hour serial marker protocol with subsequent discharge after two negative markers or minimally detected troponin without significant rise on repeat testing
What is the significance of very low or undetectable hs-T level upon presentation in patients?
It may be sufficient in ruling out acute myocardial injury
What should be noted about troponin elevation in isolation?
It is not diagnostic of ACS and can result from various cardiac and noncardiac conditions
What do elevated troponin levels in asymptomatic patients with end-stage renal disease commonly indicate?
They are commonly seen and may relate to the high prevalence of cardiac disease in this population
What is associated with elevated troponin levels in the setting of renal failure?
Increased risk of death and major cardiac and vascular morbidity
When should a repeat troponin level be measured?
In unclear circumstances to elucidate whether the elevated level may represent acute myocardial injury
What percentage of healthy subjects should a highly sensitive troponin assay result in reportable levels of troponin in?
Greater than 50%
What outcome is associated with even very low elevations of high-sensitivity troponin levels?
Adverse outcomes
What does serial high-sensitivity troponin (hs-T) assay testing combined with appropriate clinical data aid in identifying with greater than 99% sensitivity?
Patients at risk of 30-day major adverse cardiac event (MACE)
What is a concern expressed by some clinicians regarding the increased utilization of high-sensitivity troponin (hs-T)?
Increased incidental finding of myocardial injury unrelated to ACS
What is the recommended protocol for patients with chest pain presenting greater than 3 hours from symptom onset?
1-hour serial marker protocol with subsequent discharge after two negative markers or minimally detected troponin without significant rise
What is the significance of very low or undetectable hs-T level upon presentation in patients?
It may be sufficient in ruling out acute myocardial injury
What should be noted about troponin elevation in isolation?
It is not diagnostic of ACS and can be seen in various cardiac and noncardiac conditions
What do elevated troponin levels in asymptomatic patients with end-stage renal disease commonly indicate?
They are commonly seen and may relate to the high prevalence of cardiac disease rather than reduced renal clearance
What is the association between elevated troponin levels and sepsis or critically ill patients?
Elevated troponin levels are associated with increased morbidity and mortality in these patients
What should be considered when elevated troponin levels are observed in patients without evidence of ACS?
The source of these levels may be underlying noninfarction myocyte injury that occurs with certain conditions
What does current expert opinion suggest about utilizing a very low or undetectable hs-T level upon presentation for ruling out acute myocardial injury?
Consideration of such a strategy should be reserved for lower-risk patients presenting greater than 3 hours from symptom onset and only with utilization of appropriate, assay-specific cutoffs.
In which subset of patients are troponin level elevations associated with increased morbidity and mortality?
In sepsis and critically ill patients
Which serum marker is rapidly released into the circulation after cellular injury?
Myoglobin
In the setting of acute myocardial infarction (AMI), when does creatinine phosphokinase-MB (CK-MB) become detectable in the serum?
3 hours after onset of necrosis
What may lead to abnormal elevations of creatinine phosphokinase-MB (CK-MB) levels?
Muscular dystrophies
Why has creatinine phosphokinase-MB (CK-MB) been virtually eliminated from modern clinical decision rules for acute coronary syndrome evaluation in the emergency department?
Troponin level assays have become more sensitive
What is the reason for myoglobin largely falling out of favor as an early indicator of myocardial injury?
Lack of specificity for myocardial injury
Which marker is a potentially useful ACS biomarker that reportedly detects early myocardial ischemia rather than the later myocyte necrosis?
Ischemia-modified albumin (so-called cardiac albumin)
Which marker is generally used as a marker for heart failure but has good predictive power for recurrent ACS events and cardiac-related deaths?
B-type natriuretic peptide (BNP)
What is the significance of the natriuretic peptides in patients with UA, NSTEMI, and STEMI?
Excellent predictors of short-and long-term mortality
What has limited benefit in the ED evaluation of ACS with the advent of standard and high-sensitivity troponin assays?
Multimarker approaches
What is a concern regarding the increased utilization of high-sensitivity troponin (hs-T)?
Increased false positive results
What is a characteristic feature of Takotsubo cardiomyopathy on ventriculography or echocardiography?
Apical ballooning
What is released from cardiac myocytes in response to increases in ventricular wall stress?
B-type natriuretic peptide (BNP)
What may elevated plasma levels of myeloperoxidase predict, even with negative cardiac troponin levels and no evidence of myocardial necrosis?
Short-term risk of adverse cardiac events
What may be useful in evaluating the risk of a cardiac event by having long-term prognostic value for healthy individuals and potential short-term prognostic value when combined with other markers for ACS?
High-sensitivity CRP (hsCRP)
Which serum marker is rapidly released into the circulation after cellular injury, peaks at 5 to 7 hours, and returns to baseline by 24 hours?
Myoglobin
Which condition may lead to abnormal elevations of creatinine phosphokinase-MB (CK-MB) levels, potentially causing confounding interpretations?
Muscular dystrophies
In contemporary emergency departments, which marker has been virtually eliminated from modern clinical decision rules for acute coronary syndrome evaluation due to the increased sensitivity of troponin level assays?
Creatinine phosphokinase-MB (CK-MB)
Which muscle tissue contains small amounts of creatinine phosphokinase-MB (CK-MB), potentially leading to non-specific elevations in the serum?
Skeletal muscle
Which cardiac-specific myonecrosis marker is mentioned in the text?
Fatty acid–binding protein
What is the potential use of ischemia-modified albumin in ACS biomarker evaluation?
Detecting early myocardial ischemia
Which biomarker is known for its long-term prognostic value for cardiac events in healthy individuals?
C-reactive protein (CRP)
What is the primary role of natriuretic peptides in ACS patients?
Determining future prognosis
What has limited benefit in the ED evaluation of ACS, according to the text?
Multimarker approaches
What is a potential drawback of using myoglobin as an early indicator of myocardial injury?
Lack of specificity for myocardial injury
Exercise stress testing NOT included
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