PANCE - Myocardial Infarction

Here are key facts for Physician Assistant National Certifying Examination (PANCE) from the Myocardial Infarctions: Diagnosis & Treatment tutorial, focusing on clinical recognition, diagnosis, and management that are essential for certification. See the tutorial notes for further details and relevant links.

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1. Global trends: Incidence of myocardial infarctions is declining in high-income countries but rising in middle- and low-income countries. 2. Demographic patterns: Incidence after age 35, from highest to lowest: Black males > Black females > White males > White females. 3. Age and gender differences: MI occurs approximately 10 years earlier in men than in women, possibly related to risk factors such as smoking and hyperlipidemia. 4. Mortality disparities: Although mortality rates have declined overall, they remain higher in women than in men, especially for young and/or minority women. 5. Modifiable risk factors: Dyslipidemia, diabetes mellitus, hypertension, smoking (possibly including daily use of e-cigarettes), obesity, psychosocial stress, alcohol consumption, poor diet (low in fruits and vegetables). 1. Definition: Myocardial infarction is defined as myocardial injury with ischemia. 2. Presentation types:

• Prodromal symptoms: May occur days, weeks, or even months prior to the heart attack
• Acute symptoms: Experienced at the time of the event
• Silent MI: No noticeable symptoms

3. Classic presentation: Chest pain/angina variably described as dull, sharp, squeezing, pressure, or discomfort, often radiating to arms, neck, jaw, or back. 4. Atypical presentations: Not all patients experience angina—absence of chest pain and/or young age often leads to missed or delayed diagnosis, with worse outcomes. 5. Associated symptoms: Gastrointestinal issues (nausea, vomiting, indigestion), extreme fatigue/exhaustion, sleep disturbances, headaches, dizziness, lightheadedness, shortness of breath (dyspnea), anxiety, sense of impending doom. 1. ECG evaluation:

• Should be administered as soon as possible when MI is suspected
• Should be re-administered frequently to observe the evolution of the infarction
• Distinguishes between ST-segment elevated (STEMI) or Non-ST elevated (NSTEMI) myocardial infarctions
• Q-wave abnormalities may indicate size/location of current MI or prior MI

2. ECG localization:

• Lateral infarction: Leads I and aVL; left circumflex artery
• Apical infarction: Leads V5 and V6; left circumflex or right coronary arteries
• Anterior infarction: Leads V3 and V4; left anterior descending artery
• Anterior septal infarction: Leads V1 and V2; proximal left anterior descending artery
• Inferior infarction: Leads II, aVF, and III; right coronary artery or left circumflex artery
• Right ventricular infarction: Requires additional leads V3R through V6R
• Posterolateral infarction: Requires additional leads V7-V9; right coronary or left circumflex artery

3. Cardiac biomarkers:

• Essential for diagnosis, especially cardiac troponin
• Help distinguish between NSTEMI and unstable angina (only NSTEMI is associated with rising/falling troponin levels)
• Both cardiac troponin I and CK-MB peak within 24 hours of MI and fall to normal levels over time

4. Anatomical correlations: Understanding of coronary artery anatomy and territorial supply is essential for localizing infarcts. 5. Critical diagnostic point: Absence of chest pain and/or young age should not exclude MI from the differential—maintain high clinical suspicion. 1. Time-sensitive approach: Treatment should begin as soon as possible, ideally before hospital arrival, to reduce the extent of myocardial necrosis. 2. Pre-hospital treatment:

• Oxygen administration when oxygen saturation is less than 90%
• Aspirin for antiplatelet effects
• Nitrates for chest pain (morphine is an option if nitrates are ineffective)

3. Reperfusion strategies:

• Vary by severity of infarction
• Include percutaneous coronary intervention (angioplasty), coronary bypass grafting, or fibrinolytic drugs
• STEMI patients should receive emergency PCI; if unavailable, fibrinolytic drugs must be given as soon as possible

4. Treatment by MI type:

• STEMI: Emergency PCI recommended (if unavailable, immediate fibrinolytics)
• NSTEMI: Unstable, complicated cases require immediate PCI/CABG; uncomplicated cases may wait longer with possible medical management only
• Fibrinolytic therapy: Generally not recommended for NSTEMI (risks outweigh benefits)

5. Medication protocol:

• Antiplatelets (aspirin, clopidogrel, or others)
• Anticoagulation drugs (unfractionated or low molecular weight heparin)
• Beta-blockers (or calcium-channel blockers)
• Statins
• ACE-inhibitors

1. Risk factor modification: Long-term treatment focuses on reducing risk factors through improved diet and exercise. 2. Medical management: Ongoing medications to manage hypertension and hyperlipidemia. 3. Follow-up care: Regular monitoring for complications and progression to heart failure. 4. Patient education: Many patients, especially women, are unaware of risk factors and symptoms—education is a critical obstacle to prevention and treatment. 5. Secondary prevention: Aggressive risk factor management to prevent recurrent events.

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1. Atypical presentation awareness: Not all patients experience classic angina—absence should not exclude MI diagnosis. 2. Prodromal recognition: Symptoms in the days to months before acute MI may include fatigue, sleep disturbances, or vague discomfort. 3. Silent MI risk: Higher in diabetics and elderly patients—maintain high index of suspicion. 4. Gender differences: Women often present with more subtle or atypical symptoms and have worse outcomes. 5. Age considerations: Though MI occurs approximately 10 years earlier in men, young patients should not be excluded from consideration. 1. Evolution monitoring: Serial ECGs track the progression of infarction and may reveal developing complications. 2. STEMI criteria: ST-segment elevation indicates transmural injury requiring immediate reperfusion. 3. NSTEMI patterns: ST depression or T-wave changes may indicate subendocardial ischemia. 4. Localization accuracy: Different lead changes correlate with specific coronary artery territories:

• Anterior (V3-V4): Left anterior descending artery
• Inferior (II, III, aVF): Right coronary artery (or less commonly left circumflex)
• Lateral (I, aVL): Left circumflex artery

5. Extended lead sets: Right ventricular involvement (V3R-V6R) and posterior wall (V7-V9) require additional leads. 1. Troponin significance: Key biomarker for diagnosis of myocardial infarction. 2. NSTEMI vs. unstable angina: Biomarker values help distinguish these conditions—only NSTEMI shows troponin elevation. 3. Temporal considerations: Both cardiac troponin I and CK-MB peak within 24 hours of MI. 4. Serial measurements: More valuable than single determinations for diagnosis and prognosis. 5. Interpretation context: Always integrate biomarker results with clinical presentation and ECG findings. 1. Reperfusion timing: "Time is myocardium"—earlier treatment leads to better outcomes. 2. STEMI management: Emergency PCI preferred; if unavailable, immediate fibrinolytic therapy. 3. Pre-hospital initiation: Early aspirin, nitrates, and oxygen (when indicated) can limit infarct size. 4. NSTEMI approach: Risk stratification guides timing of invasive management—unstable patients need immediate intervention. 5. Pharmacotherapy selection: Evidence-based combinations of antiplatelets, anticoagulants, beta-blockers, statins, and ACE inhibitors. 1. Women: Higher mortality rates, more atypical presentations, later age of onset (approximately 10 years). 2. Minority patients: Black males have highest incidence after age 35, followed by Black females. 3. Young patients: Often missed or delayed diagnosis due to low clinical suspicion. 4. Elderly: May present with dyspnea or fatigue rather than chest pain. 5. Awareness disparities: Many patients, especially women, lack knowledge about risk factors and symptoms—patient education is crucial.

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Below is information not explicitly contained within the tutorial but important for the Physician Assistant National Certifying Examination. 1. Acute coronary syndrome: STEMI, NSTEMI, and unstable angina differentiation. 2. Non-ACS cardiac causes: Myocarditis, pericarditis, cardiomyopathy, aortic dissection. 3. Pulmonary causes: Pulmonary embolism, pneumonia, pneumothorax, pleuritis. 4. Gastrointestinal conditions: Esophageal spasm, GERD, peptic ulcer, pancreatitis, cholecystitis. 5. Other considerations: Musculoskeletal pain, herpes zoster, anxiety/panic disorder. 1. TIMI Risk Score: Predicts 14-day outcomes in ACS patients. 2. GRACE Risk Score: Predicts in-hospital and 6-month mortality. 3. HEART Score: Stratifies chest pain patients in the emergency department. 4. CRUSADE Score: Assesses bleeding risk in ACS patients. 5. Ottawa Heart Failure Risk Scale: Identifies low-risk chest pain patients. 1. P2Y12 inhibitor selection: Clinical factors influencing choice between clopidogrel, ticagrelor, and prasugrel. 2. Anticoagulation options: UFH, LMWH, fondaparinux based on clinical scenario. 3. Bleeding risk management: Balancing antiplatelet/anticoagulant therapy with bleeding risk. 4. Revascularization decisions: Culprit-only vs. complete revascularization in multivessel disease. 5. Special situations: Cardiogenic shock, mechanical complications, right ventricular infarction. 1. Cardiac rehabilitation: Evidence-based programs improving outcomes. 2. Secondary prevention optimization: Target goals for lipids, blood pressure, and glucose. 3. Medication adherence strategies: Patient education and barrier identification. 4. Return to activities: Evidence-based guidance for driving, exercise, and work. 5. Screening for depression: Associated with worse outcomes if untreated. 1. STEMI systems of care: PA role in regional networks and transfer protocols. 2. Quality metrics: Understanding core measures for MI care. 3. Transition of care: Discharge planning, medication reconciliation, follow-up arrangements. 4. Patient education: Symptom recognition, risk factor modification, medication adherence. 5. Community resources: Connecting patients with smoking cessation, cardiac rehabilitation, and support services.