PANCE - Myocardial Infarction Symptoms, Diagnosis, & Treatments

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. Demographic trends: Incidence of myocardial infarctions is declining in high-income countries but rising in middle- and low-income countries. 2. Population distribution: Within the United States, MI incidence after age 35, from highest to lowest: Black males > Black females > White males > White females. 3. Gender patterns: First MI occurs approximately 10 years earlier in men than women, possibly related to risk factors such as smoking and hyperlipidemia. 4. Mortality disparities: Despite overall declining rates, mortality remains higher in women than male peers, especially for young and/or minority women. 5. Modifiable risk factors:

• Dyslipidemia
• Diabetes mellitus
• Hypertension
• Smoking (including 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. Symptom timeline:

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

3. Typical presentation: Chest pain/angina variably described as dull, sharp, squeezing, pressure, or discomfort, often radiating to arms, neck, jaw, or back. 4. Associated symptoms:

• Gastrointestinal issues (nausea, vomiting, indigestion)
• Extreme fatigue, exhaustion, or sleep disturbances
• Headaches, dizziness, lightheadedness
• Shortness of breath (dyspnea)
• Anxiety or sense of impending doom

5. 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. 1. ECG assessment:

• Should be administered as soon as possible when MI is suspected
• 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 may indicate a 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
• Anteroseptal 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:

• Cardiac troponin is key to diagnosis
• Help distinguish between NSTEMI and unstable angina (only NSTEMI shows troponin elevation)
• Both cardiac troponin I and CK-MB peak within 24 hours of MI and fall to normal levels over time

4. Coronary anatomy correlation: Understanding anatomic distribution helps localize infarcts and predict complications. 5. Diagnostic challenges: Absence of chest pain, young age, and atypical symptoms require high index of suspicion. 1. Time-dependent approach: Treatment should begin as soon as possible, ideally before hospital arrival, to reduce myocardial necrosis. 2. Pre-hospital treatment:

• Oxygen administration when oxygen saturation is less than 90%
• Aspirin for antiplatelet effects
• Nitrates for chest pain (morphine if nitrates 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
• Unstable, complicated NSTEMI often requires immediate PCI or CABG
• Uncomplicated NSTEMI patients may wait longer (a day or two), and revascularization may not be necessary

4. Pharmacologic therapy:

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

5. Fibrinolytic considerations: Generally not recommended for NSTEMI patients because potential risks outweigh benefits. 1. Risk factor modification: Diet, exercise, smoking cessation, and stress management. 2. Medication management: Long-term therapy for hypertension and hyperlipidemia. 3. Disease progression awareness: MI is an important cause of heart failure, which is itself a significant cause of death. 4. Patient education: Many patients, especially women, are unaware of risk factors and symptoms—education is crucial. 5. Social determinants: Unawareness is a significant obstacle to prevention and treatment of myocardial infarction.

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1. Atypical presentations: Not all patients experience classic angina—maintain high index of suspicion. 2. Prodromal recognition: Symptoms in days to months before acute MI may include fatigue, sleep disturbances, or vague discomfort. 3. Pain radiation patterns: May radiate from chest to arms, neck, jaw, or back—radiation patterns help confirm diagnosis. 4. Women's presentation: More likely to present with atypical symptoms and have higher mortality. 5. Young patients: Often experience missed/delayed diagnosis due to low clinical suspicion despite presentation. 1. Timing importance: ECG should be performed ASAP when MI is suspected, with serial ECGs to monitor evolution. 2. STEMI vs. NSTEMI differentiation: Critical for determining treatment pathway and urgency. 3. Localization correlation: Different lead changes indicate specific coronary territories:

• Anterior (V3-V4): Left anterior descending artery
• Anteroseptal (V1-V2): Proximal left anterior descending artery
• Lateral (I, aVL): Left circumflex artery
• Inferior (II, III, aVF): Right coronary artery (or left circumflex in ~10% with left dominance)

4. Q-wave significance: May indicate size/location of current MI or evidence of prior MI. 5. Extended lead sets: Right ventricular (V3R-V6R) and posterior (V7-V9) infarctions require additional leads. 1. Diagnostic hierarchy: Cardiac troponin is key to diagnosis of myocardial infarction. 2. Temporal pattern: Both cardiac troponin I and CK-MB peak within 24 hours of MI. 3. NSTEMI vs. unstable angina: Only NSTEMI shows rising/falling troponin levels—crucial for treatment decisions. 4. Serial measurements: More valuable than single determinations for diagnosis. 5. Integration with clinical findings: Always interpret biomarkers in context of symptoms and ECG findings. 1. Reperfusion timing: Earlier treatment leads to better myocardial salvage and outcomes. 2. STEMI management: Emergency PCI preferred; if unavailable, immediate fibrinolytic therapy. 3. NSTEMI approach: Risk stratification guides timing of intervention—unstable patients need immediate care. 4. Pre-hospital initiation: Early oxygen (when indicated), aspirin, and nitrates can limit infarct size. 5. Pharmacotherapy selection: Comprehensive approach with antiplatelets, anticoagulants, beta-blockers, statins, and ACE inhibitors. 1. Women: Higher mortality rates, more atypical presentations, first MI approximately 10 years later than men. 2. Racial/ethnic disparities: Black males have highest incidence after age 35, followed by Black females. 3. Young patients: Often experience missed or delayed diagnosis due to low clinical suspicion. 4. Health literacy impact: Many patients, especially women, lack knowledge about risk factors and symptoms. 5. Risk factor clusters: Combinations of risks like smoking, dyslipidemia, and diabetes significantly increase MI probability.

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Below is information not explicitly contained within the tutorial but important for the Physician Assistant National Certifying Examination. 1. Aortic dissection: Sharp, tearing pain; widened mediastinum; pulse deficits. 2. Pulmonary embolism: Sudden dyspnea, tachycardia, hypoxemia; risk factors for DVT. 3. Pericarditis: Pleuritic chest pain relieved by sitting forward; diffuse ST elevations. 4. Pneumothorax: Sudden chest pain and dyspnea; decreased breath sounds; hyperresonance. 5. Gastroesophageal disorders: Pain often related to meals; may improve with antacids. 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 ACS Rule: Identifies low-risk chest pain patients. 1. Coronary angiography: Indications, contraindications, and post-procedure monitoring. 2. Thrombolytic administration: Inclusion/exclusion criteria and management of complications. 3. Arterial access site care: Monitoring for bleeding and hematoma formation. 4. Temporary pacemaker management: Indications and care for patients with high-grade AV blocks. 5. IABP and mechanical support: Basic understanding of indications and management. 1. Cardiogenic shock: Recognition, initial management, and indications for mechanical support. 2. Arrhythmias: Identification and management of post-MI dysrhythmias. 3. Mechanical complications: Early recognition of papillary muscle rupture, ventricular septal defect, free wall rupture. 4. Post-MI pericarditis (Dressler syndrome): Timing, presentation, and management. 5. Heart failure: Recognition and initial management of acute heart failure post-MI. 1. Cardiac rehabilitation: Components, benefits, and patient selection. 2. Secondary prevention targets: LDL <70 mg/dL, BP <130/80 mmHg, HbA1c <7%. 3. Return to activities: Evidence-based guidance for driving, exercise, work, and sexual activity. 4. Depression screening: Recognition and management of post-MI depression. 5. Patient education strategies: Techniques to improve medication adherence and lifestyle modifications.