323 Questions
Which clinical presentation of ACS involves ischemia but not myocardial cell death?
Unstable angina
What is the most extreme clinical manifestation of acute coronary syndrome?
Sudden cardiac death
Which development provided emergency clinicians with effective approaches for treating life-threatening dysrhythmias occurring due to ACS?
External defibrillators
Who inaugurated the era of cardiopulmonary resuscitation (CPR) in 1960?
Kouwenhoven
Which type of myocardial infarction is characterized by myocardial cell death and ST segment elevation?
ST segment elevation myocardial infarction
Which ACS subtype involves ischemia but not ST segment elevation?
Non–ST segment elevation myocardial infarction
What is frequently included in the ACS spectrum of illnesses and represents the most extreme clinical manifestation of acute coronary syndrome?
Sudden cardiac death
What provided an important tool in the management of sudden cardiac death?
Cardiopulmonary resuscitation (CPR)
Which ACS subtype is characterized by myocardial cell death but not ST segment elevation?
Non–ST segment elevation myocardial infarction
What is frequently involved in the ACS spectrum of illnesses and involves pulseless ventricular tachycardia or ventricular fibrillation?
Sudden cardiac death
What has been added to the chest pain evaluation strategy as the most recent development?
High-sensitivity troponin testing
What is the focus of the STEMI systems of care approach?
The time-sensitivity of treatment
What is the focus of the rule-out (R/O) myocardial infarction (MI) strategy?
Detection of ACS events
What is the primary concern when attempting to lower the missed MI rate in the ED?
Increased unnecessary testing with associated risk
What has improved interventional success in the treatment of STEMI?
Newer stenting devices
What is the goal of combination therapies studied for STEMI patients?
To optimize reperfusion and adjunctive therapies
What is the primary concern when attempting to lower the missed MI rate in the ED?
Identifying and promptly treating acute myocardial infarction
What has improved interventional success in the treatment of STEMI?
Selective coronary arteriography
What revolutionized the management of patients with coronary artery disease, including chronic, stable presentations and acute coronary syndrome?
Selective coronary arteriography
Who inaugurated the era of cardiopulmonary resuscitation (CPR) in 1960?
Kouwenhoven
What is the focus of the STEMI systems of care approach?
Time-sensitivity of treatment and multidisciplinary composition of the management team
What has improved interventional success in the treatment of STEMI?
Newer stenting devices and various platelet and coagulation system inhibitors
What is the goal of combination therapies studied for STEMI patients?
Further optimizing reperfusion and adjunctive therapies
What is the most recent development added to the chest pain evaluation strategy?
High-sensitivity troponin testing
What has been added to the chest pain evaluation strategy to reduce the total evaluation time and improve throughput?
High-sensitivity troponin testing
What is the primary concern when attempting to lower the missed MI rate in the ED?
Increased unnecessary testing with associated risk, health system costs, and less resource availability for higher-risk patients
What is the focus of the rule-out (R/O) myocardial infarction (MI) strategy?
Shortening the total time, rendering it more efficient, and making it safer with respect to detection of ACS events
What has revolutionized the treatment of patients with STEMI, starting in the late 1980s?
Fibrinolytic therapy and interventional catheter-based techniques
What is the age-adjusted prevalence of coronary heart disease for men?
7.2%
What is the leading cause of death among adults in many industrialized countries?
Heart disease
What accounts for over 1 million deaths in the United States annually?
Ischemic heart disease
What has contributed to a significant reduction in age-adjusted mortality from CAD in the United States and Canada?
Improved management of hypertension, hyperlipidemia, and diabetes mellitus
What is the approximate 30-day mortality rate for patients who experience an acute myocardial infarction (AMI)?
30%
What percentage of patients with AMI die from an ACS-related dysrhythmia within 2 hours of the event initiation?
20%
What percentage of patients with ACS, including unstable angina (UA) and AMI, are discharged from the ED?
1%
What percentage of patients with myocardial infarction are rehospitalized within 1 year of their index event?
45%
What percentage of patients with acute coronary syndrome (ACS), including both unstable angina (UA) and acute myocardial infarction (AMI), are discharged from the emergency department (ED)?
5%
What percentage of patients with AMI die within 30 days of the acute myocardial infarction?
30%
Approximately how many persons experience an AMI every year in the United States?
900,000
What is the primary cause for presenting to the ED among men with approximately 49 million annual ED visits in the United States?
Chest pain
What is the age-adjusted prevalence of coronary heart disease for women?
4.2%
What is the leading cause of death among adults in many industrialized countries?
Heart disease
What has contributed to a significant reduction in age-adjusted mortality from CAD in the United States and Canada?
Diminished mortality from AMI
What is the approximate percentage of deaths from cardiovascular disease that occur in women?
More than 50%
What percentage of patients with acute coronary syndrome (ACS), including both unstable angina (UA) and acute myocardial infarction (AMI), are discharged from the emergency department (ED)?
2%
What percentage of patients with AMI die within 30 days of the acute myocardial infarction?
30%
What is the approximate 30-day mortality rate for patients who experience an acute myocardial infarction (AMI)?
30%
What is the leading cause for presenting to the ED among men with approximately 49 million annual ED visits in the United States?
Chest pain
What is the approximate percentage of deaths from cardiovascular disease that occur in women?
50%
What is the age-adjusted prevalence of coronary heart disease for men?
7.2%
What is the age-adjusted prevalence of heart disease?
10.6%
What accounts for over 1 million deaths in the United States annually?
Cardiovascular disease
Which of the following is considered a less severe manifestation of coronary heart disease?
Stable angina
What is the most severe form of Acute Coronary Syndrome (ACS) according to some experts?
Sudden cardiac death from pulseless ventricular tachycardia or ventricular fibrillation
Which manifestation of coronary heart disease is characterized by myocardial cell death and ST segment elevation?
STEMI
Which of the following is a characteristic of stable angina pectoris?
It is not considered a form of acute coronary syndrome (ACS)
What is the most severe form of acute coronary syndrome (ACS) according to some experts?
Sudden cardiac death resulting from pulseless ventricular tachycardia or ventricular fibrillation
Which condition is characterized by myocardial cell death but not ST segment elevation?
Non-ST segment elevation myocardial infarction (NSTEMI)
Which of the following is the most severe form of Acute Coronary Syndrome (ACS) according to some experts?
Sudden cardiac death due to pulseless ventricular tachycardia
What is the characteristic feature of stable angina pectoris?
Transient and episodic chest discomfort
What is the major difference between Non-ST segment elevation myocardial infarction (NSTEMI) and ST segment elevation myocardial infarction (STEMI)?
Involvement of ST segment elevation on ECG
How is unstable angina broadly defined from a semantic perspective?
Angina that is new onset or occurring at rest or with minimal exertion
When is angina considered to be 'rest angina'?
Angina occurring at rest, lasting longer than 20 minutes, and occurring within 1 week of presentation
What is 'new-onset angina'?
Angina of at least CCS classification class II severity, with onset within the previous 2 months
How is 'increasing or progressive angina' diagnosed?
When a previously known anginal pattern becomes more frequent, longer in duration, or increased by one class within the previous 2 months of at least class III severity
Which type of angina is caused by coronary artery vasospasm at rest and may be relieved by exercise or NTG?
Variant angina (Prinzmetal angina)
Which organization developed clinical criteria for acute myocardial infarction (AMI)?
American College of Cardiology (ACC)
What is the primary cause of acute myocardial infarction (AMI)?
Plaque rupture
What differentiates NSTEMI from STEMI at presentation?
Elevated cardiac troponin values
How many primary types of infarction are described by the classification of AMI?
5
What represents the most extreme clinical manifestation of acute coronary syndrome (ACS)?
Sudden unexpected cardiac death
Which descriptor fails to adequately describe the coronary event and its related pathophysiology?
Non-Q wave MI
What differentiates stable angina from unstable angina?
Severity of symptoms
What is the primary focus of diagnostic and management issues for acute myocardial infarction (AMI)?
Subtype of MI encountered
What is the major difference between NSTEMI and STEMI in terms of myocardial injury?
Extent of myocardial cell death
What has improved interventional success in the treatment of STEMI?
Advancements in medical technology
What is the characteristic feature of stable angina pectoris?
Relief by exercise or NTG
Which of the following is considered rest angina?
Angina occurring at rest, lasting longer than 20 minutes, and occurring within 1 week of presentation
What defines new-onset angina?
Angina that is new onset or occurring at rest or with minimal exertion
What characterizes increasing or progressive angina?
Angina that is worsening from a previously stable pain occurrence pattern
What is the defining characteristic of unstable angina from a semantic perspective?
Angina that is new onset or occurring at rest or with minimal exertion
What is the defining characteristic of unstable angina from a semantic perspective?
It can be severe, possibly indicating an acute myocardial infarction (AMI)
Which type of angina is caused by coronary artery vasospasm at rest and may be relieved by exercise or NTG?
Variant angina (Prinzmetal angina)
What represents the most extreme clinical manifestation of acute coronary syndrome (ACS)?
Acute myocardial infarction
What is the major difference between Non-ST segment elevation myocardial infarction (NSTEMI) and ST segment elevation myocardial infarction (STEMI)?
The location of myocardial cell death
What is the characteristic feature of stable angina pectoris?
It is predictable and reproducible
What is the focus of the STEMI systems of care approach?
Restoring blood flow to the heart muscle
What is the differentiation between STEMI and NSTEMI important for?
Management, outcome, and prognosis for patients with AMI
What is frequently involved in the ACS spectrum of illnesses and involves pulseless ventricular tachycardia or ventricular fibrillation?
Acute myocardial infarction
What is the approximate 30-day mortality rate for patients who experience an acute myocardial infarction (AMI)?
20-30%
What is the classification of AMI types based on?
Different clinical situations
What differentiates NSTEMI from STEMI at presentation?
The presence of myocardial cell death
What is the primary cause of acute myocardial infarction (AMI)?
Plaque rupture and thrombus formation
Which of the following is NOT a semantic definition of unstable angina?
Angina occurring during physical activity
How long must angina last to be considered 'rest angina'?
Longer than 20 minutes
When is angina considered 'new-onset'?
Within the previous 2 months
How is 'increasing or progressive angina' diagnosed?
When a previously known anginal pattern becomes more frequent or longer in duration
What percentage of vessel stenosis usually results in ischemic symptoms at rest?
95%
Which factor determines myocardial oxygen consumption?
Heart rate
What is the characteristic of vulnerable, or unstable, fibro-lipid plaques?
They consist of a lipid-rich core separated from the arterial lumen by a fibromuscular cap
What initiates the pathophysiologic process of ACS?
Rupture of vulnerable plaques
What is the primary cause of thrombus formation in Acute Coronary Syndrome (ACS)?
Endothelial damage and atherosclerotic plaque disruption
What makes platelet-rich thrombi more resistant to fibrinolysis in ACS?
Higher concentration of platelets
What is the most critical factor in myocardial infarction (MI) according to angiographic studies?
Acute events of plaque rupture, platelet activation, and thrombus formation
What is the likely consequence of extensive collateral vessel circulation in cases of acute stenosis of the coronary vessel in unstable angina (UA)?
Prevents cessation of blood flow, averting frank infarction
What contributes to further myocardial injury in Acute Coronary Syndrome (ACS) as debris from the occlusive plaque lesion is released?
Embolization into the distal vessel
What can the introduction of calcium, oxygen, and cellular elements into ischemic myocardium lead to?
Irreversible myocardial damage
What is the likely role of neutrophils in reperfusion injury in Acute Coronary Syndrome (ACS)?
Occluding capillary lumens and accelerating the inflammatory response
What is the primary cause of approximately 10% of MIs, occurring without significant underlying coronary artery disease (CAD)?
Coronary artery spasm and subsequent thrombus formation
What further compromises blood flow after significant coronary vessel occlusion in Acute Coronary Syndrome (ACS)?
Vasospasm induced by local mediators and vasoactive substances
What is the characteristic feature of platelet-rich thrombi in Acute Coronary Syndrome (ACS)?
Resistance to fibrinolysis
What is the primary role of platelets in the thrombotic response to rupture of coronary artery plaque and subsequent ACS?
Major role in thrombus formation
What determines myocardial oxygen consumption?
Heart rate, afterload, contractility, and wall tension
At what percentage of vessel stenosis does inadequate perfusion usually result in ischemic symptoms at rest?
95%
What characterizes stable fibrous plaques in CAD?
Produce anginal symptoms with exercise and increased myocardial oxygen consumption
What is the composition of vulnerable, or unstable, fibro-lipid plaques in CAD?
Lipid-rich core separated from the arterial lumen by a fibromuscular cap
Which of the following is the primary cause of approximately 10% of MIs, occurring without significant underlying coronary artery disease (CAD)?
Coronary artery spasm and subsequent thrombus formation
What makes platelet-rich thrombi more resistant to fibrinolysis in ACS?
Presence of platelet activation and thrombus formation
What is the major difference between NSTEMI and STEMI in terms of myocardial injury?
Extent of myocardial injury
What represents the most extreme clinical manifestation of acute coronary syndrome (ACS)?
Complete obstruction of the vessel lumen
What further compromises blood flow after significant coronary vessel occlusion in Acute Coronary Syndrome (ACS)?
Vasospasm induced by local mediators
What is the primary cause of thrombus formation in Acute Coronary Syndrome (ACS)?
Endothelial damage and atherosclerotic plaque disruption
What has revolutionized the treatment of patients with STEMI, starting in the late 1980s?
Primary percutaneous coronary intervention (PCI)
What characterizes stable fibrous plaques in CAD?
Lack of thrombus formation
What is the characteristic feature of stable angina pectoris?
Predictable pattern of chest discomfort
What is the focus of the rule-out (R/O) myocardial infarction (MI) strategy?
Differentiating MI from other causes of chest pain
What further compromises blood flow after significant coronary vessel occlusion in Acute Coronary Syndrome (ACS)?
Vasomotor hyperreactivity
What is the characteristic of vulnerable, or unstable, fibro-lipid plaques?
High risk of rupture and thrombosis
What determines myocardial oxygen consumption?
Heart rate, afterload, contractility, and wall tension
At what percentage of coronary arterial vessel stenosis does inadequate perfusion usually result in ischemic symptoms at rest?
95%
What characterizes vulnerable, or unstable, fibro-lipid plaques in CAD?
Consist of a lipid-rich core separated from the arterial lumen by a fibromuscular cap
What initiates the pathophysiologic process of ACS?
Rupture of vulnerable, or unstable, fibro-lipid plaques
What is the primary cause of thrombus formation in Acute Coronary Syndrome (ACS)?
Endothelial damage and atherosclerotic plaque disruption
What further compromises blood flow after significant coronary vessel occlusion in Acute Coronary Syndrome (ACS)?
Local mediators and vasoactive substances inducing vasospasm
What characterizes the most critical factors in the infarction in Acute Coronary Syndrome (ACS)?
Acute events of plaque rupture, platelet activation, and thrombus formation
What is the primary cause for presenting to the ED among men with approximately 49 million annual ED visits in the United States?
Acute Coronary Syndrome (ACS)
What further complicates blood flow after significant coronary vessel occlusion in Acute Coronary Syndrome (ACS)?
Vasomotor hyperreactivity and coronary vasospasm
What makes platelet-rich thrombi more resistant to fibrinolysis in ACS?
Platelets play a major role in the thrombotic response to rupture of coronary artery plaque
What is the characteristic feature of stable angina pectoris?
Pain relieved by rest or nitroglycerin
What is the approximate percentage of deaths from cardiovascular disease that occur in women?
40%
What characterizes stable fibrous plaques in CAD?
Less than 50% stenotic
What provided an important tool in the management of sudden cardiac death?
Angiographic studies
What characterizes increasing or progressive angina?
Becomes more frequent, prolonged, or severe
What is the primary role of platelets in the thrombotic response to rupture of coronary artery plaque and subsequent ACS?
Play a major role in the thrombotic response
What is the primary challenge in diagnosing ACS in the prehospital setting?
Limited adjunctive diagnostic tools
Which population may exhibit less remarkable ACS presentations?
Women
What is a nontraditional symptom of ACS frequently exhibited by diabetic patients?
Dyspnea
What is the impact of prehospital 12-lead ECG on paramedic scene time?
Increases by only 1 to 3 minutes
What is the primary challenge in diagnosing ACS in the prehospital setting?
Limited availability of adjunctive diagnostic tools
What offers high specificity and positive predictive value for STEMI in patients with atraumatic chest pain?
Prehospital 12-lead ECG
What are nontraditional symptoms of ACS frequently exhibited by diabetic patients?
Dyspnea
What do older adults commonly note as the primary manifestation of ACS?
Extreme weakness
What is a common atypical symptom of Acute Coronary Syndrome (ACS) frequently exhibited by diabetic patients?
Dyspnea
What is the primary manifestation of ACS in older adults, according to the text?
Extreme weakness
What is the key challenge in diagnosing ACS in the prehospital setting?
Chest pain being a poor predictor of AMI diagnosis
What is the impact of prehospital 12-lead ECG on paramedic scene time, according to the text?
Increases by only 1 to 3 minutes
Which symptom is the most common angina equivalent presentation in ACS?
Dyspnea
What should raise suspicion of ACS in the absence of a known history of gastroesophageal reflux disease?
Heartburn
Which symptoms are very uncommon sole presenting symptoms in ACS?
Nausea, emesis, anxiety, and fatigue
What is a common misdiagnosis in cases of missed AMI?
Gastroesophageal and upper gastrointestinal (GI) maladies
Which term refers to a tightening sensation, not necessarily a pain?
Angina
Which structures can be involved in the radiation of discomfort associated with angina pectoris?
Neck, jaw, shoulders, or arms
Which symptoms are characteristically associated with angina pectoris?
Nausea, vomiting, diaphoresis, weakness
What are the usual locations for discomfort associated with angina pectoris?
Substernal or precordial
Which of the following is a characteristic feature of angina pectoris?
Discomfort described as a tightness or pressure
What structures can be involved in the radiation of discomfort associated with angina pectoris?
Both arms and shoulders
Which symptoms are characteristically associated with angina pectoris?
Nausea and diaphoresis
What is a term used to describe symptoms that arise without chest discomfort as a presenting pattern of known ischemic coronary disease?
Atypical angina
Which symptom is the most common angina equivalent presentation of ACS?
Dyspnea
What should raise suspicion of ACS in the absence of a known history of gastroesophageal reflux disease?
Heartburn
Which presenting complaint may occasionally occur as the single presenting complaint in the ACS patient, especially in the extreme older patient population?
Excessive fatigue
What is a common misdiagnosis in cases of missed AMI?
Upper gastrointestinal maladies
What is a possible atypical feature of pain in ACS?
Pleuritic or positional pain
Which factor is associated with presentations of ACS that do not feature classic anginal pain?
Diabetes mellitus
What symptom is notably present in patients with AMI below age 85?
Dyspnea
What percentage of ED patients ultimately diagnosed with AMI did not have chest pain on presentation?
One-third
What is the most common anginal equivalent complaint in patients older than 85 years?
Dyspnea
Which population is at heightened risk for ACS and presenting with anginal equivalents?
Patients with diabetes mellitus
What is a significant risk factor for AMI without a classic chest pain presentation?
Female sex
What symptom is less likely to be attributed to cardiac symptoms by women?
Indigestion
What is a disparity in treatment approaches related to race and ethnicity in patients with acute manifestations of coronary heart disease?
Underrecognized symptoms in ACS
What characteristic is associated with worse outcomes in ACS presentations without classic anginal chest pain?
Delayed diagnosis and treatment
What is the primary focus of diagnostic and management issues for acute myocardial infarction (AMI)?
Recognizing varied presentations of ACS
What should emergency clinicians consider for all patients presenting with any chest discomfort, shortness of breath, weakness, dizziness, nausea, or vomiting?
The diagnosis of ACS
Which symptom may serve as an anginal equivalent in patients with ACS?
Dyspnea
What is a common feature of ACS presentations without classic anginal chest pain?
Dementia
What percentage of ED patients ultimately diagnosed with AMI did not have chest pain on presentation?
33%
What symptoms are notably present in patients below age 85 with AMI?
Dyspnea, stroke, weakness, and altered mental status
What is a common atypical symptom of Acute Coronary Syndrome (ACS) frequently exhibited by diabetic patients?
All of the above
Which age group is more likely to have an anginal equivalent complaint, especially dyspnea?
Patients aged 85 years and older
What is a significant risk factor for AMI without a classic chest pain presentation?
Female sex
What is a disparity in treatment approaches related to in patients with acute manifestations of coronary heart disease?
Race and ethnicity
What is the approximate increased in-hospital mortality for patients aged 85 years and older compared to those aged 65 years or younger?
10%
What do women with AMI frequently attribute their cardiac symptoms to?
Anxiety
What is a heightened risk factor for ACS and presenting with anginal equivalents?
Diabetes mellitus
What is more likely to occur in older adults due to physiologic stress from another acute condition (e.g., trauma, infection)?
Concurrent coronary ischemia
What are common findings in patients with severe forms of unstable angina (UA) and acute myocardial infarction (AMI)?
Bradycardia, tachycardia, hypotension, and pulmonary edema
What is the real incidence of reproducible chest wall tenderness in ACS?
Extremely rare
What percentage of patients with acute myocardial infarction (AMI) experience bradydysrhythmia and atrioventricular (AV) conduction blocks?
25% to 30%
What findings are associated with the ill ACS patient?
Pale appearance, anxiety, and diaphoresis
What is the response pattern of atropine in symptomatic bradydysrhythmias in the first few hours after inferior STEMI?
Atropine tends to be responsive
What is the prognosis for patients with AV block in the setting of anterior STEMI?
Poor response to therapy and poor prognosis
When does primary ventricular fibrillation commonly occur in patients with AMI?
Within the first 4 hours of AMI
How is cardiogenic shock defined in the context of acute myocardial infarction (AMI)?
End-organ hypoperfusion resulting from decreased cardiac output unresponsive to restoration of adequate preload
What is a common finding in patients with severe forms of unstable angina (UA) and acute myocardial infarction (AMI)?
Pale appearance, anxiety, and diaphoresis
What is the real incidence of reproducible chest wall tenderness in patients with ACS?
Extremely rare
What is the occurrence rate of bradydysrhythmia and atrioventricular (AV) conduction blocks in patients with AMI?
25% to 30%
What is the significance of sinus bradycardia in the context of AMI?
It is usually seen
Which type of bradydysrhythmias in the setting of AMI tend not to respond to atropine?
Conduction abnormalities appearing beyond 24 hours of AMI
What is the estimated percentage of patients with AMI who experience primary ventricular fibrillation within the first 4 hours?
60%
What is cardiogenic shock defined as in the context of acute myocardial infarction (AMI)?
End-organ hypoperfusion resulting from decreased cardiac output unresponsive to restoration of adequate preload
Which statement is true regarding tachydysrhythmias in the setting of AMI?
Tachydysrhythmias may be atrial or ventricular in origin and not all require treatment
What is a potentially life-threatening condition that should be strongly considered when evaluating a patient for nontraumatic chest pain?
Pulmonary embolism
Which condition is considered a non–life-threatening cause of nontraumatic chest pain, but can lead to significant morbidity?
Costochondritis
What condition is included in the differential diagnosis of ACS and is characterized by various gastrointestinal maladies?
Esophageal perforation
Which of the following is a non–life-threatening cause of nontraumatic chest pain?
Costochondritis
What should be strongly considered when evaluating a patient for nontraumatic chest pain?
Pulmonary embolism
Which condition is characterized by myocardial cell death but not ST segment elevation?
Non-STEMI
What ECG finding is diagnostic for ST-elevation myocardial infarction (STEMI)?
New ST elevation of greater than 1 mm in at least two contiguous leads
What ECG finding indicates an increased cardiovascular risk in the context of ACS?
Total ST segment deviation
What does ST segment elevation on ECG establish candidacy for in the management of ACS?
Emergent reperfusion therapy
Why is rhythm determination essential in the context of ACS?
To identify compromising dysrhythmias
What is a limitation of the diagnostic abilities of the ECG in ACS?
Individual variations in coronary anatomy and preexisting coronary disease
What is emphasized as the most important diagnostic study for patients with chest symptoms?
The patient’s reported history and the emergency clinician’s interpretation of that history
What is a key consideration regarding the interpretation of a single ECG in isolation?
It is neither 100% sensitive nor 100% specific for AMI
What can be misleading when evaluating a currently asymptomatic patient with a history of intermittent anginal chest pain?
A normal or nonspecifically abnormal ECG
What is important to consider about the elapsed time from symptom onset to normal ECGs in ruling out AMI?
It does not necessarily rule out an AMI even up to 12 hours after symptom onset
What can happen to patients with an initial nondiagnostic ECG who later develop AMI during hospitalization?
They are often pain-free or minimally uncomfortable on initial ED presentation
What should not be overemphasized when evaluating a currently asymptomatic patient with a history of intermittent anginal chest pain?
A normal or nonspecifically abnormal ECG
What remains uncertain despite morphologic changes that may occur in ACS?
Current clinical use of ECG information
Which ECG finding is diagnostic for ST-elevation myocardial infarction (STEMI)?
New ST elevation of greater than 1 mm in at least two contiguous leads, except for leads V2 and V3
What ECG finding may indicate an increased cardiovascular risk in the context of ACS?
Total ST segment deviation
What does the presence of LBBB on ECG suggest in the context of ACS?
Diagnosis of STEMI
What does the ST segment elevation on ECG establish in the context of ACS?
Candidacy for emergent reperfusion therapy
What is the role of the ECG in diagnosing ACS?
It may be normal or nonspecifically abnormal in early ACS events
What limits the diagnostic abilities of the ECG in ACS?
Variations in coronary anatomy and preexisting coronary disease
What should not be overemphasized when interpreting a normal or nonspecifically abnormal ECG?
The elapsed time from symptom onset to the normal ECG
What is the most important diagnostic study for patients with an initial nondiagnostic ECG?
The patient's reported history and interpretation by the emergency clinician
What is a potential consequence of relying solely on a single ECG for diagnosing ACS?
Missing early ACS events, including AMI
What is often seen in patients with an initial nondiagnostic ECG who later develop AMI during hospitalization?
"Pain-free" or minimally uncomfortable presentation at first
What is one limitation of using a single ECG to rule out AMI?
High negative predictive value but not 100% sensitive even up to 12 hours after symptom onset
What remains uncertain about the current clinical use of ECG information in diagnosing ACS?
The diagnostic abilities of the ECG
What is emphasized as more important than a single ECG for diagnosing ACS?
Patient's reported history and interpretation by emergency clinician
What is a common finding in ECGs of adults with chest pain?
ST segment elevation
What is a characteristic of the ST segment elevation in 'benign early repolarization' (BER)?
Concave morphology
How is ST segment elevation of 'benign early repolarization' (BER) different from the pathologic ST segment elevation of STEMI?
BER is a normal finding, while STEMI is a dynamic phenomenon
What should be used as the baseline when measuring ST segment elevation?
The most definable, constant baseline evident on the ECG
What is the earliest electrocardiographic finding in STEMI?
Hyperacute T wave
In addition to acute ischemia, what else can cause tall T waves on an ECG?
Hyperkalemia
What morphologic variations of ST segment elevation can be seen in STEMI?
"Tombstoned" elevation
What characterizes the upsloping portion of the ST segment in STEMI?
"Progresses as it elevates"
What is the earliest electrocardiographic finding in STEMI?
Hyperacute T wave
What may be included in the differential diagnosis of the tall T wave seen in acute ischemia?
Hyperkalemia
What morphologic variations of ST segment elevation can be seen as STEMI progresses?
"Tombstoned" elevation
What is a potential cause for concave or scooped elevation of the ST segment in STEMI?
Ischemia in specific myocardial regions
What is the baseline typically used when measuring ST segment elevation on an ECG?
TP segment
In what population is 'benign early repolarization' (BER) commonly seen?
Young males
What differentiates normal ST segment elevation from the pathologic ST segment elevation of STEMI?
The latter is a dynamic phenomenon
What type of ST segment elevation morphology is atypical for STEMI?
Concave morphology
Which type of myocardial infarction is characterized by myocardial cell death and ST segment elevation?
STEMI
Where is the reciprocal ST segment depression best seen in an inferior MI?
Lead aVL
What do reciprocal changes in the setting of STEMI increase?
Specificity of ECG in AMI
In which leads may anterior STEMI feature reciprocal ST segment depression?
Leads II, III, or aVF
What does ST segment depression generally represent in ED patients with chest pain or anginal equivalent?
Subendocardial ischemia
What type of contour is less frequently associated with ischemic ST segment depression?
Upsloping
In which condition can subendocardial ischemic ST segment depression be diffuse, spanning anterior and inferior leads?
Unstable angina or NSTEMI
Which condition is included in the differential diagnosis of ST segment depression?
Pulmonary embolism
Which ECG finding may indicate reciprocal ST segment depression with STEMI?
ST segment elevation in leads V8 and V9
In which type of MI is reciprocal ST segment depression more frequently manifested in lead aVL?
Inferior MI
Which ECG finding characterizes reciprocal changes in the setting of STEMI?
ST segment depression in lead III
Where is reciprocal ST segment depression best seen in the case of inferior MI?
Lead aVL
Which of the following is a less frequently associated contour with ischemic ST segment depression?
Upsloping
In the context of Acute Coronary Syndrome (ACS), which condition may cause ST segment depression and can be a differential diagnosis?
Pulmonary embolism
What type of ECG finding is diagnostic for ST-elevation myocardial infarction (STEMI)?
ST segment elevation
Which condition can mimic ischemic ST segment depression on an ECG?
Ventricular hypertrophy
In which leads are T waves normally upright?
Leads I, II, and V3 to V6
Which type of T wave inversions is associated with Wellens syndrome?
Deep symmetrical (type I) or biphasic (type II) T wave changes in the anterior precordial leads
Where are T wave vectors normally variable?
Leads III, aVL, and aVF
How are T wave inversions of ACS classically described?
Narrow and symmetrical
In which leads are T waves normally upright?
Leads I, II, and V3 to V6
Which type of T wave inversions are classically narrow and symmetrical in ACS?
Deep symmetrical T wave inversions (type I)
In which leads are T waves normally inverted?
Lead aVR
Where may T waves be normally inverted in addition to lead V1?
Lead V2
Which leads primarily reflect septal involvement in anterior infarctions?
Leads V1 and V2
In anterior STEMI, reciprocal ST segment depression may occur in which leads?
Leads III and aVF
ST segment elevation in lead aVR should prompt consideration of occlusion of which artery?
Left main coronary artery
Which artery is likely to be involved when the ST segment elevation extends to leads I and aVL?
First diagonal branch of the left anterior descending artery
Which artery is usually responsible for serving the inferior wall of the heart and AV node?
Right coronary artery
What ECG finding indicates occlusion of the left circumflex coronary artery or first diagonal?
ST elevation in leads I and aVL with reciprocal ST segment depression in leads III, aVF, and V1
What is the characteristic ECG finding associated with de Winter ECG pattern?
Prominent T waves with J point depression producing ST segment depression seen in the precordial leads, coupled with ST segment elevation in lead aVR
What may ST segment elevation in lead V1 in the presence of an inferior MI suggest?
Concomitant right ventricular infarction
What is the characteristic feature of high lateral infarctions?
ST elevation in leads I and aVL suggesting occlusion of the left circumflex coronary artery or first diagonal
What is the characteristic ECG finding associated with lateral infarctions?
Changes in some or all of the lateral leads I, aVL, V5, and V6 with reciprocal ST segment depression seen in leads III, aVF, and V1
What is indicated by ST segment depression in leads V1 to V3 during an inferior MI?
Reciprocal change
What may be associated with diffuse endocardial ischemia due to hypoperfusion?
ST segment elevation greater in lead III than in lead II, accompanied by ST segment depression in lead aVL
What is suggested by greater ST segment elevation occurring alongside greater elevation occurring on either leads aVR or V1?
Left main disease when occurring alongside greater ST segment elevation occurs on either leads aVR or V1
Which leads primarily reflect changes in septal involvement in anterior infarctions?
V1 and V2
In anterior STEMI, which leads may show reciprocal ST segment depression?
III and aVF
Which artery serves the anterior wall and its occlusion can lead to anterior or anterolateral STEMI?
Left anterior descending artery
What is a high-risk presentation in ACS that should prompt consideration of occlusion of the left main coronary artery?
ST segment elevation in lead aVR
Which leads primarily reflect septal involvement in an anterior myocardial infarction?
V1 and V2
In anterior STEMI, reciprocal ST segment depression may occur in which leads?
III and aVF
Which artery is likely to be involved when the ST segment elevation extends to leads I and aVL in anterior wall STEMI?
First diagonal branch of the left anterior descending artery
What should prompt consideration of occlusion of the left main coronary artery in a patient with ACS symptoms?
ST segment elevation in lead aVR
What is the characteristic ECG finding associated with de Winter ECG pattern?
Prominent T waves with J point depression producing ST segment depression in precordial leads, coupled with ST segment elevation in lead aVR
What has been added to the chest pain evaluation strategy to reduce the total evaluation time and improve throughput?
Prehospital 12-lead ECG
What is emphasized as more important than a single ECG for diagnosing ACS?
Serial ECGs
What is indicated by ST segment depression in leads V1 to V3 during an inferior MI?
Reciprocal change
What do older adults commonly note as the primary manifestation of ACS?
Chest discomfort
What ECG findings are suggestive of acute posterior myocardial infarction?
Horizontal ST segment depression and an upright T wave
Where does the culprit lesion causing posterior infarctions most commonly occur?
Right coronary artery
What percentage of acute myocardial infarction (AMI) cases demonstrate elevated ST segments only in accessory leads, posterior leads V7 through V9?
5%
Why is diagnosing acute posterior myocardial infarction challenging with a 12-lead ECG?
No electrodes are placed directly over the heart’s posterior wall
What percentage of all AMIs are estimated to be posterior infarctions?
15%
Which leads may show reciprocal ST segment changes in the context of acute posterior myocardial infarction?
Leads V1 to V3
What combination of findings in leads V1 to V3 increases the diagnostic accuracy for acute posterior MI?
Horizontal ST segment depression with an upright T wave
Where may the culprit lesion be located in cases of posterior infarctions?
Right coronary artery, its posterior descending branch, or left circumflex artery
What is the association between right ventricular infarctions and inferior MI?
Right ventricular infarctions are usually associated with inferior MI
What percentage of inferior infarctions have associated infarction of the right ventricle?
One-third
In what type of MI may an anterior MI involve some right ventricular infarction?
Anterior MI
In what percentage of inferior infarctions is there associated infarction of the right ventricle?
Less than 33%
Which type of myocardial infarction is right ventricular infarction usually associated with?
Inferior or inferoposterior MI
What is the likelihood of right ventricular infarction occurring in isolation?
Rarely occurs in isolation
Study Notes
Unstable Angina and Acute Myocardial Infarction Definitions
- Unstable angina (UA) is different from stable angina and can be severe, possibly indicating an acute myocardial infarction (AMI), and should be treated aggressively in such cases.
- UA can be defined by the patient's presentation and from a pathophysiologic perspective, involving plaque rupture, thrombus formation, and vasospasm.
- Variant angina, also known as Prinzmetal angina, is caused by coronary artery vasospasm at rest and may be relieved by exercise or NTG.
- Acute myocardial infarction involves myocardial cell death with necrosis, and clinical criteria have been developed by the American College of Cardiology (ACC) and European Society for Cardiology (ESC).
- Myocardial injury is defined by elevated cardiac troponin values, and myocardial infarction is when there is acute myocardial injury with specific symptoms, electrocardiographic abnormalities, imaging evidence, or angiographic evidence.
- The classification of AMI includes types 1 through 5, each representing different clinical situations.
- The five primary types of infarction are described by the classification: spontaneous MI, MI secondary to ischemia, sudden unexpected cardiac death, MI associated with coronary instrumentation, and MI associated with coronary artery bypass grafting.
- Diagnostic and management issues for AMI differ depending on the subtype of MI encountered.
- Serum markers and ECG abnormalities classify AMI at presentation as either NSTEMI or STEMI, with important implications for management, outcome, and prognosis.
- Previous descriptors, such as transmural, non-transmural, Q wave, and non-Q wave MI, fail to adequately describe the coronary event and its related pathophysiology, electrocardiographic presentation, and pathologic outcome.
- The differentiation between STEMI and NSTEMI has important implications in management, outcome, and prognosis for patients with AMI.
Unstable Angina and Acute Myocardial Infarction Definitions
- Unstable angina (UA) is different from stable angina and can be severe, possibly indicating an acute myocardial infarction (AMI), and should be treated aggressively in such cases.
- UA can be defined by the patient's presentation and from a pathophysiologic perspective, involving plaque rupture, thrombus formation, and vasospasm.
- Variant angina, also known as Prinzmetal angina, is caused by coronary artery vasospasm at rest and may be relieved by exercise or NTG.
- Acute myocardial infarction involves myocardial cell death with necrosis, and clinical criteria have been developed by the American College of Cardiology (ACC) and European Society for Cardiology (ESC).
- Myocardial injury is defined by elevated cardiac troponin values, and myocardial infarction is when there is acute myocardial injury with specific symptoms, electrocardiographic abnormalities, imaging evidence, or angiographic evidence.
- The classification of AMI includes types 1 through 5, each representing different clinical situations.
- The five primary types of infarction are described by the classification: spontaneous MI, MI secondary to ischemia, sudden unexpected cardiac death, MI associated with coronary instrumentation, and MI associated with coronary artery bypass grafting.
- Diagnostic and management issues for AMI differ depending on the subtype of MI encountered.
- Serum markers and ECG abnormalities classify AMI at presentation as either NSTEMI or STEMI, with important implications for management, outcome, and prognosis.
- Previous descriptors, such as transmural, non-transmural, Q wave, and non-Q wave MI, fail to adequately describe the coronary event and its related pathophysiology, electrocardiographic presentation, and pathologic outcome.
- The differentiation between STEMI and NSTEMI has important implications in management, outcome, and prognosis for patients with AMI.
Page 849-862 (Electrocardiographic Differential Diagnosis of ST Segment Elevation-(NOT included)
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