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Questions and Answers

What does NSTEMI stand for in the context of acute coronary syndrome?

Non-ST-Elevation Myocardial Infarction (correct)

Non-ST-Temporal Myocardial Injury

New ST-Elevation Myocardial Infarction

Narrowed ST-Elevation Myocardial Ischemia

What is the primary cause of the imbalance in myocardial oxygen supply and demand in acute coronary syndrome?

Severe emotional stress

Coronary artery thrombosis (correct)

High blood pressure levels

Increased physical activity

Which condition is NOT classified under non-ST elevation acute coronary syndromes?

Both A and B

Unstable Angina

Stable Angina (correct)

NSTEMI

In unstable angina, what typically signifies a worsening of the patient's condition?

Occurrence at rest or low level of activity Signup and view all the answers

Which option best describes the nature of the plaque formation in acute coronary syndrome?

Formation leading to coronary artery thrombosis Signup and view all the answers

What is considered a severe chest pain characteristic indicating a potential NSTEMI?

Occurs at rest and lasts more than 10 minutes. Signup and view all the answers

Which of the following is a preferred biomarker for diagnosing NSTEMI?

Cardiac Troponin 1 (cTn) Signup and view all the answers

In the context of diagnosing NSTEMI, which assessment is not typically performed?

Imaging studies like X-rays Signup and view all the answers

What condition is indicated by cardiac troponin 1 levels being elevated?

Non-ST elevation myocardial infarction (NSTEMI) Signup and view all the answers

What is the main initial treatment for patients with NSTE-ACS?

Anti-ischemic therapy, bed rest, and oxygen Signup and view all the answers

Which medication is considered the cornerstone of anti-thrombotic treatment in NSTE-ACS?

Aspirin Signup and view all the answers

Which of the following anticoagulants has been found to be superior to unfractionated heparin in reducing recurrent cardiac events?

Enoxaparin Signup and view all the answers

What monitoring is essential for patients admitted with NSTE-ACS?

Continuous ECG monitoring for ST-segment deviation and arrhythmias Signup and view all the answers

Which anticoagulant is a direct thrombin inhibitor suitable for use prior to or during PCI?

Bivalirudin Signup and view all the answers

What is the first step in the invasive treatment strategy for acute coronary syndrome?

Coronary arteriography within 48 hours Signup and view all the answers

Which of the following scenarios would prompt a conservative treatment strategy to become more invasive?

Positive biomarkers of necrosis Signup and view all the answers

Which of the following is NOT a component of the long-term medical management of acute coronary syndrome?

Increased physical activity Signup and view all the answers

In a conservative management strategy, when is coronary arteriography performed?

If ST-segment changes recur Signup and view all the answers

What primarily characterizes Prinzmetal’s variant angina?

Occurs at rest and is associated with ST segment elevation. Signup and view all the answers

Which risk factor is most commonly associated with Prinzmetal's variant angina?

Cigarette smoking Signup and view all the answers

What are the provocative tests used to diagnose Prinzmetal's variant angina?

Hyperventilation and intercoronary acetylcholine Signup and view all the answers

Which treatment is specifically recommended for Prinzmetal's variant angina?

Nitrates and calcium channel blockers Signup and view all the answers

What should be avoided in the treatment of Prinzmetal's variant angina due to possible adverse effects?

Aspirin Signup and view all the answers

What is the prognosis for patients diagnosed with Prinzmetal’s variant angina after five years?

90-95% survival rate Signup and view all the answers

Which of the following factors is NOT considered a common risk factor for acute plaque rupture?

Hypercoagulability Signup and view all the answers

What characterizes the chest pain often associated with STEMI?

Heavy squeezing and crushing Signup and view all the answers

Among the following, which is identified as a precipitating factor for STEMI?

Vigorous physical exercise Signup and view all the answers

What type of histological characteristic might indicate a plaque’s susceptibility to rupture?

Rich lipid core and thin fibrous cap Signup and view all the answers

Which of the following is NOT a differential diagnosis for chest pain suggestive of STEMI?

Pulmonary embolism Signup and view all the answers

Which symptom is commonly associated with STEMI?

Chest Pain characterized as heavy squeezing Signup and view all the answers

What is a characteristic feature of the location of chest pain during a STEMI?

Central chest and/or epigastrium Signup and view all the answers

Which factor is a known precipitating cause of STEMI?

Vigorous physical exercise Signup and view all the answers

Which associated symptom might indicate impending doom in a STEMI patient?

Sense of impending doom Signup and view all the answers

During a physical examination of a patient with STEMI, which finding is likely?

Diaphoretic and anxious Signup and view all the answers

Which differential diagnosis is relevant for evaluating chest pain suggestive of STEMI?

Acute aortic dissection Signup and view all the answers

What is the maximum target delay for obtaining a 12-lead ECG after the first medical contact?

10 minutes Signup and view all the answers

Which of the following biomarkers is typically elevated in patients experiencing STEMI?

Cardiac-specific troponin T (cTnT) Signup and view all the answers

What technique helps in detecting the presence of wall motion abnormalities during an echocardiogram?

Two-dimensional echocardiography Signup and view all the answers

What complication can Doppler echocardiography help detect following STEMI?

Mitral regurgitation Signup and view all the answers

When are cardiac biomarkers detectable in the peripheral blood?

Once overflow from cardiac lymphatics occurs Signup and view all the answers

What is the role of cardiac MRI in the assessment of myocardial infarction?

To utilize a technique referred to as late enhancement Signup and view all the answers

What other imaging technique, besides echocardiography, is mentioned for myocardial assessment?

Radionuclide imaging Signup and view all the answers

What is defined as the first medical contact (FMC)?

The time a patient is assessed by medical personnel who can interpret the ECH. Signup and view all the answers

What does the term 'rescue PCI' refer to?

Emergent PCI performed after failed fibrinolysis. Signup and view all the answers

What characterizes the 'primary PCI' approach?

Immediate PCI without previous fibrinolysis. Signup and view all the answers

What does the pharmacoinvasive strategy combine?

Fibrinolysis with either rescue PCI or routine early PCI. Signup and view all the answers

What signifies a STEMI diagnosis?

Presence of ischemic symptoms and ST-segment elevation. Signup and view all the answers

What is the time goal for initiating PCI following first medical contact?

120 minutes Signup and view all the answers

Which complication may arise from coronary artery reocclusion after fibrinolysis?

Arrhythmias Signup and view all the answers

What is the maximum recommended door-to-needle time for fibrinolysis?

90 minutes Signup and view all the answers

What is one indication for urgent PCI during hospitalization?

Positive exercise stress test Signup and view all the answers

What is one of the major goals in the management of patients presenting with acute coronary syndrome?

Minimize time to reperfusion therapy Signup and view all the answers

What is the dietary recommendation for fat intake during the first 4–12 hours?

≤30% Signup and view all the answers

Which medication is indicated for sedation to manage inactivity?

Lorazepam Signup and view all the answers

What is the initial dose of Nitroglycerin during the first 24-48 hours?

5-10 mcg/min Signup and view all the answers

What type of diet is recommended to manage bowel health?

Diet rich in bulk Signup and view all the answers

Which of the following is NOT recommended for patients with STEMI?

CCBs Signup and view all the answers

What is the primary reason for the use of Aspirin in patients experiencing STEMI?

To rapidly inhibit Cox-1 in platelets Signup and view all the answers

Which medication is administered to STEMI patients who cannot tolerate ACE inhibitors?

Angiotensin receptor blockers (ARB) Signup and view all the answers

How does beta-adrenoceptor blockade affect myocardial oxygen supply and demand?

It improves the supply-demand relationship Signup and view all the answers

What is the maximum initial bolus dose of Unfractionated Heparin (UFH) for treating STEMI patients?

60 U/kg, maximum 4000 U Signup and view all the answers

Which characteristic is essential for administering Mineralocorticoid Receptor Antagonists in STEMI patients?

Creatinine level in men ≥2.5 mg/dL Signup and view all the answers

What advantage does Enoxaparin (LMWH) offer compared to Unfractionated Heparin?

High bioavailability with subcutaneous administration Signup and view all the answers

What is a common treatment recommendation in the early hours following STEMI?

Bed rest for the first 6-12 hours Signup and view all the answers

Which newer P2Y12 ADP receptor antagonist is known to be more effective than Clopidogrel?

Prasugrel Signup and view all the answers

Study Notes

Acute Coronary Syndrome (ACS)

ACS represents a spectrum of conditions associated with sudden reduced blood flow to the heart.

Non-ST-Elevation Myocardial Infarction (NSTEMI)

NSTEMI is a type of ACS characterized by partial blockage in the coronary arteries leading to heart muscle damage.

Unstable Angina

Unstable angina is another form of ACS, indicating significant heart stress without significant heart muscle damage.

Pathophysiology

ACS occurs due to an imbalance between myocardial oxygen supply and demand, leading to ischemia.

Causes of ACS

Plaque formation in coronary arteries can lead to blockage.
Coronary artery thrombosis results from plaque rupture, impeding blood flow.

Key Points

Immediate recognition and treatment of ACS are crucial to prevent severe heart damage.
Risk factors for ACS include high cholesterol, hypertension, smoking, diabetes, and sedentary lifestyle.

Diagnosis Overview

Diagnosis involves a combination of history, physical examination, age assessment, ECG, and cardiac troponins (cTns) levels.

History and Physical Examination

Severe chest pain is a critical symptom, characterized by:
- Occurrence at rest or with minimal exertion, lasting longer than 10 minutes.
- Recent onset of symptoms, specifically within the past two weeks.
- Crescendo pattern indicating an increase in severity, duration, or frequency compared to previous episodes.

Electrocardiogram (ECG)

ECG evaluation is essential for diagnosing cardiac-related issues and should be performed alongside other diagnostic tools.

Cardiac Biomarkers

Cardiac Troponin 1 (cTn) is a crucial biomarker for identifying myocardial necrosis, especially in NSTEMI (Non-ST Elevation Myocardial Infarction).
cTn is highly sensitive and relatively specific, making it the preferred marker for distinguishing NSTEMI from unstable angina (UA).
Elevated cTn levels indicate ongoing myocardial injury and are vital for confirming NSTEMI diagnosis.

Medical Management of NSTE-ACS

Patients identified with NSTE-ACS based on clinical features, cardiac troponin (cTn) levels, or ST-T-wave changes on ECG require hospital admission.
Continuous ECG monitoring is essential for observing ST-segment deviation and cardiac arrhythmias, preferably in a specialized cardiac unit.
Bed rest is prescribed, along with oxygen therapy for patients exhibiting hypoxemia.

Anti-ischemic Treatment

The initial treatment includes anti-ischemic measures, along with bed rest and oxygen for hypoxemic patients.

Anti-thrombotic Therapy

Antiplatelet and anticoagulant therapy are crucial components of NSTE-ACS treatment.
Initial antiplatelet treatment includes aspirin administration.

Anticoagulant Options

Four main parenteral anticoagulant therapies can be utilized alongside antiplatelet agents:
- Unfractionated heparin (UFH) has historically been essential in managing NSTE-ACS.
- Enoxaparin, a low-molecular-weight heparin (LMWH), has shown superior effectiveness over UFH in reducing recurrent cardiac events.
- Bivalirudin acts as a direct thrombin inhibitor, achieving similar efficacy to UFH or LMWH, particularly used during percutaneous coronary intervention (PCI).
- Fondaparinux is a synthetic factor Xa inhibitor, comparable in effectiveness to enoxaparin but associated with a lower risk of major bleeding events.

Invasive vs Conservative Treatment Strategies

Invasive Strategy: Utilizes anti-ischemic and antithrombotic medications followed by coronary arteriography within 48 hours after presentation. This approach leads to coronary revascularization through PCI (Percutaneous Coronary Intervention) or CABG (Coronary Artery Bypass Grafting).
Conservative Strategy: Starts with anti-ischemic and antithrombotic drugs, followed by a selective invasive approach. Patients are closely monitored, with coronary arteriography indicated if specific conditions arise, such as:
- Presence of epicardial coronary stenosis on coronary computed tomography angiography.
- Recurrence of rest pain or ST-segment changes.
- Positive biomarkers indicating myocardial necrosis.
- Severe ischemia demonstrated on a stress test.

Long-Term Management

Medical Management: Involves a structured approach to patient care:
- Dual antiplatelet therapy with Aspirin (ASA) and P2Y12 inhibitors for 12 months; if the patient is at high risk of bleeding, monotherapy may be initiated afterwards.
- Use of Beta-Blockers to manage heart rate and workload.
- ACE inhibitors (ACEi) or Angiotensin II Receptor Blockers (ARBs) to help regulate blood pressure.
- Lipid-lowering therapy aimed at achieving target LDL cholesterol levels (LDL-C).

Characteristics of Prinzmetal's Variant Angina

Occurs at rest, not triggered by exertion, and is linked to ST segment elevation on ECG.
Primarily caused by focal spasm of epicardial coronary arteries.

Clinical Profile

Predominantly affects younger individuals with minimal risk factors other than cigarette smoking.
Cardiac exam typically shows unremarkable findings.
Diagnosis involves observing transient ST-segment elevation associated with rest pain.

Angiographic Manifestations

Diagnostic hallmark: transient coronary spasm detected during angiography.
Provocative tests include hyperventilation and intercoronary acetylcholine (Ach) to induce and confirm focal coronary stenosis or provoke rest angina with ST-segment elevation.

Treatment and Management

Primary medications include nitrates and calcium channel blockers (CCB).
Aspirin is contraindicated as it may worsen ischemic episodes due to increased sensitivity of coronary tone to prostacyclin synthesis changes.
Statins are beneficial in reducing adverse effects related to coronary artery disease.
Coronary revascularization is considered for patients with discrete, flow-limiting, proximal fixed obstructive lesions.

Prognosis

The 5-year survival rate is high, ranging from 90% to 95%.
Initial phase lasts about 6 months, marked by frequent angina episodes and increased risk of cardiac events.

Pathophysiology of Acute Plaque Rupture

Risk factors for acute plaque rupture include hypertension (HTN), smoking, lipid accumulation, multiple coronary risk factors, and unstable angina (UA).
Less common factors involve hypercoagulability, collagen vascular disease, cocaine abuse, and intracardiac thrombi or masses which can cause coronary emboli.
Histological characteristics of plaques prone to disruption consist of a rich lipid core and a thin fibrous cap.
Rarely, STEMI may be induced by coronary artery occlusion from coronary emboli, congenital abnormalities, coronary spasm, or systemic inflammatory diseases.

Clinical Presentation of STEMI

About half of STEMI cases exhibit precipitating factors such as vigorous physical exercise, emotional stress, or significant medical/surgical illness.
Common symptoms include:
- Chest Pain:
  - Character: Typically described as deep, heavy, squeezing, and crushing; can also present as stabbing or burning.
  - Location: Mainly in the central chest and/or epigastrium; may radiate to arms and occipital area, but not below the umbilicus or trapezius.
- Associated symptoms: Weakness, nausea, sweating, vomiting, anxiety, and a profound sense of impending doom.
- Less common signs include sudden loss of consciousness (LOC), confusion, profound weakness, arrhythmias, peripheral embolism, and unexplained drops in arterial pressure.

Differential Diagnosis

Conditions to consider in differential diagnosis include:
- Acute pericarditis
- Acute aortic dissection
- Costochondritis
- Gastrointestinal disorders

Pathophysiology and Clinical Presentation

Precipitating factors are present in around half of STEMI cases; common triggers include vigorous physical exercise, emotional stress, and medical or surgical conditions.
Typical chest pain associated with STEMI is described as deep, heavy, squeezing, or crushing in nature; may vary and can also be stabbing or burning.
Pain is primarily located in the central chest and/or epigastric region, sometimes radiating to the arms and occipital area; pain never radiates below the umbilicus or to the trapezius region.
Associated symptoms may include weakness, nausea, sweating, vomiting, anxiety, and a profound sense of impending doom.
Less common symptoms can occur, including sudden loss of consciousness (LOC), confusion, severe weakness, arrhythmias, peripheral embolism, and unexplained drop in arterial pressure.
Differential diagnoses to consider include acute pericarditis, acute aortic dissection, costochondritis, and gastrointestinal disorders.

Physical Examination Findings

Patients often present as anxious, restless, and diaphoretic.
Patients may exhibit behaviors aimed at pain relief such as moving in bed, changing positions, or stretching.
Anterior STEMI is associated with sympathetic nervous system hyperactivity, resulting in tachycardia and hypertension.
Inferior STEMI often presents with parasympathetic hyperactivity, leading to bradycardia and/or hypotension.

Electrocardiogram

A 12-lead ECG recording should be done at first medical contact (FMC) with a maximum delay of 10 minutes.
ST-segment elevation can evolve to Q waves in most patients presenting with an acute myocardial infarction (MI).
Detection of transmural MI occurs with the presence of Q waves or loss of R waves; if only transient ST-segment and T-wave changes are present, nontransmural MI may be indicated.

Serum Cardiac Biomarkers

Cardiac biomarkers appear in peripheral blood when the cardiac lymphatics cannot clear the infarct zone interstitium, leading to a spillover into circulation.
Cardiac-specific troponin T (cTnT) and I (cTnI) may significantly increase after ST-Elevation Myocardial Infarction (STEMI), often exceeding the upper reference limit.

Cardiac Imaging

2D echocardiography typically shows abnormalities in wall motion, aiding in swift diagnosis.
The absence or presence of wall motion abnormalities detected via echocardiography informs management decisions regarding reperfusion therapy such as fibrinolysis or percutaneous coronary intervention (PCI).
Echocardiography can reveal right ventricular (RV) infarction, ventricular aneurysm, pericardial effusion, and left ventricular (LV) thrombus.
Doppler echocardiography assists in detecting and quantifying ventricular septal defects and mitral regurgitation—serious complications of STEMI.

Other Imaging Techniques

Cardiac MRI, particularly late enhancement techniques, help in further evaluation of myocardial damage.
Radionuclide imaging techniques are also applicable for assessing cardiac conditions.

Definitions of Key Terms in Cardiology

First Medical Contact (FMC): Refers to the initial assessment of a patient experiencing cardiac symptoms by qualified healthcare personnel (physician, paramedic, nurse, or EMS personnel) either in a prehospital setting or upon arrival at a hospital, such as the emergency department.
STEMI Diagnosis: Defined as the moment when a patient presenting with ischemic symptoms is identified as having ST-segment elevation on an ECG, indicating a serious heart condition.
Primary PCI (Percutaneous Coronary Intervention): An urgent procedure involving the use of a balloon, stent, or other approved devices to treat the infarct-related artery (IRA) without prior fibrinolytic therapy, aimed at restoring blood flow to the heart.
Rescue PCI: An emergency PCI performed as soon as possible when initial fibrinolytic treatment fails to restore adequate blood flow, providing a critical intervention to prevent further damage.
Pharmacoinvasive Strategy: A combined approach that utilizes fibrinolysis followed by either a rescue PCI in case of treatment failure or a routine early PCI strategy following a successful fibrinolysis, optimizing patient outcomes.

Prognosis in Cardiac Events

Prognosis is influenced by two main types of complications: electrical (arrhythmias) and mechanical (pump failure).

Prehospital Care

Effective prehospital care can impact overall patient outcomes, transitioning quickly to hospital management.

Emergency Room Management

Main objective: Reduce the duration from first medical contact to beginning reperfusion therapy, maximizing patient recovery chances.
Patients may need to be transferred from non-PCI hospitals to PCI-capable facilities.

Reperfusion Therapy Timing

Ideal initiation of Percutaneous Coronary Intervention (PCI) should occur within 120 minutes of first medical contact.
Fibrinolysis should be initiated within 30 minutes of patient presentation, with a target door-to-needle time of 90 minutes.

Indicators for Urgent PCI

Consider urgent PCI if there's coronary artery reocclusion indicated by ST segment elevation or recurrent chest pain.
Development of recurrent ischemia, such as recurrent angina or a positive exercise stress test prior to discharge, is another indicator for urgent PCI consideration.

Anti-thrombotics

Aspirin: Chewed 160-325 mg tablet for rapid Cox-1 inhibition, reducing thromboxane A2 levels. Followed by daily doses of 75-162 mg.
P2Y12 ADP Receptor Antagonists: Prasugrel and Ticagrelor show greater efficacy than Clopidogrel for ischemic complications in STEMI patients receiving PCI.
Unfractionated Heparin (UFH): Initial bolus of 60 U/kg (max 4000U) with infusion of 12 U/kg/h; APTT target is 1.5-2 times control value.
Enoxaparin (LMWH): High bioavailability allows subcutaneous administration, providing reliable anticoagulation without monitoring.
Fondaparinux: Demonstrated superiority over placebo in untreated STEMI patients; however, its safety compared to UFH is uncertain.

Beta-Adrenoceptor Blockers

Improves myocardial oxygen supply-demand balance.
Reduces pain and infarct size.
Decreases incidence of serious ventricular arrhythmias.

Inhibition of RAAS

ACE Inhibitors: Lower mortality rates after STEMI; greater benefits in high-risk groups (elderly, anterior infarction, previous infarction, depressed left ventricular function).
ARBs: Administered to STEMI patients intolerant to ACE inhibitors, especially those with heart failure signs.
Mineralocorticoid Receptor Antagonists (e.g., Spironolactone, Eplerenone): Used in STEMI patients with LVEF ≤40%, symptomatic heart failure or diabetes, and without significant renal dysfunction.

Others

Activity: Recommend bed rest for 6-12 hours, followed by upright posture to reduce pulmonary capillary wedge pressure.
Diet: NPO for initial 4-12 hours; fat intake ≤30%, cholesterol ≤300 mg/d; complex carbohydrates should constitute 50-55% of intake.
Bowel Management: High-bulk diet and routine stool softeners like dioctyl sodium sulfosuccinate (200 mg/d) recommended.
Sedation: Agents like Diazepam (5 mg), Oxazepam (15-30 mg), or Lorazepam (0.5-2 mg) to assist with inactivity.
Nitroglycerin: Initial dose of 5-10 mcg/min, with a maximum of 200 mcg/min while maintaining hemodynamic stability for the first 24-48 hours.
Calcium Channel Blockers (CCB): No role in treating STEMI patients.

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Description

Test your knowledge on Acute Coronary Syndrome, focusing on Non-ST-Elevation Myocardial Infarction (NSTEMI) and unstable angina. Explore the pathophysiology and causes of ACS, including the critical concepts of myocardial oxygen supply and demand balance.