Chest Pain, Coronary Artery Disease, ACS & Myocardial Infarction
Build a complete MCCQE approach to acute and chronic ischemic chest pain: exclude immediately life-threatening diagnoses, distinguish chronic coronary disease from ACS, interpret ECG and high-sensitivity troponin, choose reperfusion/invasive strategies, recognize post-MI complications and deliver evidence-based secondary prevention.
Module 2 purpose: master the complete chest-pain and coronary-disease pathway from first presentation through diagnosis, reperfusion, complications and secondary prevention. This candidate-facing course page contains study content only; MCQs remain in the separate Cardiology QBank.
Learning objectivesComplete topic mapSession 2.1Session 2.2Session 2.3Session 2.4Rapid reviewPost-MI timingReferences
Module 2 learning objectives
- Recognize and stabilize immediately life-threatening causes of chest pain before completing a routine diagnostic work-up.
- Differentiate ischemic chest discomfort from aortic, pulmonary, pericardial, gastrointestinal and musculoskeletal causes while avoiding over-reliance on one symptom descriptor.
- Use serial 12-lead ECGs, high-sensitivity troponin and focused testing to distinguish STEMI, NSTEMI, unstable angina, type 2 MI and non-ischemic myocardial injury.
- Recognize posterior and right-ventricular infarction and other high-risk ischemic ECG patterns that may be missed on a single standard tracing.
- Select an appropriate testing strategy for chronic coronary disease based on clinical likelihood, ability to exercise, baseline ECG, renal function, contrast exposure and whether the result will change management.
- Use symptom-relieving antianginal therapy and event-preventing therapy appropriately in chronic coronary disease.
- Initiate safe evidence-based ACS treatment, including antiplatelet therapy, anticoagulation, anti-ischemic therapy and early lipid lowering while respecting contraindications and bleeding risk.
- Choose between primary PCI, transfer for PCI and fibrinolysis using time-to-reperfusion principles and contraindications.
- Recognize electrical, hemodynamic, inflammatory, thrombotic and mechanical complications of myocardial infarction by their typical timing and bedside presentation.
- Plan secondary prevention after ACS, including antithrombotic therapy, lipid lowering, smoking cessation, BP/diabetes management, physical activity, cardiac rehabilitation, adherence and follow-up.
- Recognize important special presentations including older adults, women, diabetes, CKD, spontaneous coronary artery dissection, vasospasm, MINOCA and atypical/anginal-equivalent symptoms.
Module 2 — Complete syllabus & topic map
- Immediate chest-pain stability assessment: ABCs, perfusion, oxygenation, mental status, shock and malignant arrhythmia
- Chest-pain history: onset, provocation, quality, radiation, duration, exertional pattern and associated symptoms
- Ischemic symptoms and anginal equivalents: dyspnea, diaphoresis, nausea, fatigue, epigastric or jaw/arm discomfort
- Life-threatening chest-pain differential: ACS, acute aortic syndrome, pulmonary embolism, tension pneumothorax, tamponade/pericarditis and esophageal rupture
- Other chest-pain causes: GERD/esophageal spasm, pneumonia/pleurisy, costochondritis, cervical radiculopathy, anxiety/panic and herpes zoster
- Cardiovascular risk factors and pretest/clinical likelihood of obstructive CAD
- Serial ECG strategy and comparison with prior tracings
- High-sensitivity troponin: 99th percentile, rise/fall pattern, timing and assay-specific interpretation
- Acute myocardial injury versus myocardial infarction
- Type 1 MI versus type 2 MI and common supply-demand triggers
- Unstable angina in the high-sensitivity troponin era
- Chest radiography, bedside ultrasound and echocardiography in selected acute chest-pain presentations
- When CT angiography is needed for aortic disease or pulmonary embolism rather than coronary testing
- Clinical decision pathways and risk scores as adjuncts rather than substitutes for judgment
- Chronic coronary disease / stable angina: clinical features, severity and functional limitation
- Silent ischemia and atypical/less typical presentations
- Exercise ECG: appropriate use and limitations
- Stress echocardiography and nuclear perfusion imaging
- Coronary CT angiography and coronary calcium concepts
- When invasive coronary angiography is appropriate in chronic disease
- Antianginal therapy: beta-blockers, calcium-channel blockers, short- and long-acting nitrates and individualized combinations
- Nitrate safety: hypotension, right-ventricular infarction and phosphodiesterase-5 inhibitor exposure
- Event prevention in chronic CAD: antiplatelet therapy when indicated, lipid lowering, BP/diabetes control, smoking cessation and exercise
- Revascularization principles: symptom relief, high-risk anatomy, left-main/multivessel disease and shared decision-making
- Vasospastic angina and coronary spasm
- Microvascular angina / INOCA and persistent symptoms despite nonobstructive coronary arteries
- NSTE-ACS: NSTEMI versus unstable angina
- NSTE-ACS ECG patterns: ST depression, T-wave inversion, transient ST elevation and dynamic changes
- NSTE-ACS risk assessment: recurrent ischemia, hemodynamic/electrical instability, GRACE concepts and bleeding risk
- Initial ACS medications: aspirin, P2Y12 inhibition, anticoagulation, nitrates, analgesia, oxygen only when indicated and early statin therapy
- Early invasive versus selective invasive strategy in NSTE-ACS
- Renal dysfunction, anemia, thrombocytopenia and bleeding-risk considerations in ACS
- STEMI diagnostic patterns and territory localization
- Inferior MI, right-ventricular MI and right-sided leads
- Posterior MI and posterior leads
- Anterior/septal/lateral infarction and culprit-vessel concepts
- Primary PCI as preferred reperfusion when timely and feasible
- Fibrinolysis eligibility, absolute/relative contraindications and rescue-PCI concepts
- Cardiogenic shock after MI and urgent revascularization principles
- Post-MI arrhythmias: VT/VF, AF, sinus bradycardia and AV block
- Papillary-muscle rupture and acute severe mitral regurgitation
- Ventricular septal rupture
- Left-ventricular free-wall rupture and tamponade/PEA
- Early post-MI pericarditis and later post-cardiac-injury syndrome
- Left-ventricular aneurysm and mural thrombus
- Recurrent ischemia, reinfarction and acute stent thrombosis
- Post-ACS antiplatelet strategy and duration individualized to ischemic and bleeding risk
- Secondary-prevention lipid therapy and escalation when LDL-C remains above recommended thresholds
- Cardiac rehabilitation, exercise, diet, smoking cessation, vaccination and medication adherence
- Return-to-activity, work and driving considerations according to clinical recovery and local guidance
- Spontaneous coronary artery dissection (SCAD), especially in younger/peripartum patients
- MINOCA: myocardial infarction with nonobstructive coronary arteries and need for etiologic evaluation
- Cocaine/amphetamine and other stimulant-associated ischemia or vasospasm
- ACS in older adults, women, diabetes and CKD
Acute CareChronic CareAssessment / DiagnosisManagementPatient safety / emergencyHealth Promotion & PreventionMedical Expert
Study Session 2.1 — Acute Chest Pain & Life-Threatening Differential
Complete MCCQE coronary-disease study review
Core topics & learning goals
- Start with hemodynamic and respiratory stability before attempting to “name” the diagnosis.
- Use a targeted chest-pain history while recognizing that ischemia can present without classic substernal pressure.
- Identify ACS, acute aortic syndrome, pulmonary embolism, tension pneumothorax, tamponade/pericarditis and esophageal rupture as must-not-miss diagnoses.
- Obtain and interpret an early ECG and repeat it when symptoms evolve or initial findings are nondiagnostic.
- Use high-sensitivity troponin serially and distinguish myocardial injury from myocardial infarction.
- Select targeted chest radiography, echocardiography/POCUS, CT aorta or PE imaging when the differential requires it.
Clinical recognition & investigation
- Look for shock, hypoxemia, heart failure, neurologic deficit, pulse/BP asymmetry, new murmur, unilateral breath-sound loss and pericardial/tamponade clues.
- Ask about prior CAD/PCI/CABG, diabetes, CKD, smoking, dyslipidemia, hypertension, family history, cocaine/stimulant exposure and thromboembolic risk.
- Treat new diaphoresis, unexplained dyspnea, nausea or collapse in a high-risk patient as possible ischemia even without severe chest pain.
- Use serial assessment because ECG, troponin, pain and hemodynamics may change over time.
Management & patient-safety priorities
- Stabilize airway/breathing/circulation, monitor rhythm, obtain IV access and activate condition-specific emergency pathways early.
- Give aspirin promptly for suspected ACS when not contraindicated, but avoid reflexive antithrombotic therapy if aortic dissection is strongly suspected.
- Use supplemental oxygen for hypoxemia or respiratory compromise rather than routinely in normoxemic ACS.
- Do not delay definitive treatment of tension pneumothorax, tamponade, massive PE, aortic catastrophe or acute coronary occlusion for low-value tests.
MCCQE exam traps
- Chest-wall tenderness or pain improved by antacid does not completely exclude ACS.
- A normal initial ECG does not rule out ACS; serial ECGs are important when suspicion persists.
- A single negative troponin obtained too early may not safely exclude MI; follow an assay-specific serial pathway.
- Elevated troponin means myocardial injury, not automatically plaque-rupture/type 1 MI.
Authoritative sources for this study session
1. The first 5 minutes — stability before diagnosis
- Airway/breathing: assess work of breathing, oxygen saturation and signs of pulmonary edema, pneumothorax or severe PE.
- Circulation: assess BP, pulse, perfusion, capillary refill, mental status and evidence of shock. Obtain continuous cardiac monitoring when ACS or arrhythmia is possible.
- Immediate ECG: an early 12-lead ECG is central to triage. Repeat during recurrent pain or if the first tracing is nondiagnostic.
- Do not delay treatment: unstable patients need simultaneous resuscitation and focused diagnosis, not a sequential routine work-up.
2. Chest-pain phenotype — useful but never absolute
- Ischemic: pressure, heaviness, squeezing or tightness, often exertional and possibly radiating to arm, shoulder, jaw, back or epigastrium.
- Pleuritic: worse with inspiration; consider PE, pneumothorax, pneumonia/pleurisy or pericarditis.
- Positional: pericarditis may improve sitting forward; reflux or musculoskeletal causes can also vary with position.
- Abrupt maximal-at-onset pain: raises concern for acute aortic syndrome, pneumothorax or PE depending on context.
- Avoid the exam error of using the labels “typical” and “atypical” as binary rules; age, comorbidity and associated features modify probability.
3. Anginal equivalents and populations with less classic symptoms
- Dyspnea, diaphoresis, nausea/vomiting, profound fatigue, presyncope/syncope, epigastric discomfort or isolated arm/jaw discomfort may represent myocardial ischemia.
- Older adults, women, people with diabetes and patients with CKD may present with less dramatic chest pain and more dyspnea, weakness or autonomic symptoms.
- Do not dismiss ischemia solely because pain is absent, mild, reproducible or described unusually.
4. ECG strategy in acute chest pain
- Look for ST elevation, ST depression, T-wave inversion, hyperacute T waves, reciprocal changes, new conduction abnormalities and dynamic changes.
- Compare with previous ECGs when available and repeat tracings during recurrent symptoms.
- Consider right-sided leads in inferior MI with hypotension/JVP elevation and posterior leads when V1–V3 show reciprocal posterior changes.
- A nondiagnostic ECG does not end ACS evaluation when clinical suspicion remains meaningful.
5. High-sensitivity troponin — injury versus infarction
- Myocardial injury: troponin above the assay-specific 99th percentile. A rise/fall supports acute injury.
- Myocardial infarction: acute myocardial injury plus clinical evidence of ischemia such as ischemic symptoms, ischemic ECG changes, new regional wall-motion abnormality or coronary thrombus.
- Type 1 MI: acute atherothrombotic plaque disruption. Type 2 MI: ischemic supply-demand mismatch without acute coronary thrombosis.
- Non-ischemic injury can occur with myocarditis, heart failure, PE, sepsis, tachyarrhythmia, renal disease and other systemic illness.
- Interpret the trajectory, timing, symptoms, ECG and clinical context—not one isolated troponin value.
6. Chest radiograph, POCUS and echocardiography
- Chest radiography can identify pneumothorax, pulmonary edema, pneumonia and some alternative diagnoses, but a normal film does not exclude ACS, PE or dissection.
- POCUS/urgent echocardiography can rapidly identify severe LV/RV dysfunction, pericardial effusion/tamponade, acute MR/VSD clues and major volume/hemodynamic abnormalities.
- Do not use normal LV function to exclude ischemia; small NSTEMIs may have normal global EF.
7. Acute aortic syndrome — when antithrombotics can be dangerous
- Clues include abrupt severe chest/back pain, pulse or BP differential, focal neurologic deficit, new aortic regurgitation, syncope or shock.
- If suspected, prioritize rapid aortic imaging and BP/impulse-control strategy while obtaining specialist help.
- Do not reflexively give fibrinolysis or anticoagulation for “chest pain + ST/T changes” when dissection remains a serious possibility.
8. PE, tension pneumothorax, tamponade and esophageal rupture
- PE: pleuritic pain, dyspnea, tachycardia, hypoxemia, DVT risk or syncope; use pretest probability and validated PE pathways rather than indiscriminate CT.
- Tension pneumothorax: severe respiratory distress, hypotension, unilateral absent breath sounds; decompress immediately if clinically diagnosed.
- Tamponade: hypotension, raised JVP, tachycardia, pulsus paradoxus and effusion on ultrasound; urgent drainage when unstable.
- Esophageal rupture: severe chest pain after forceful vomiting/instrumentation, systemic toxicity or mediastinal air; urgent surgical evaluation.
9. Risk scores and disposition — tools, not replacements for judgment
- Structured ED pathways may incorporate history, ECG, age/risk factors and serial troponin to identify low-, intermediate- and high-risk patients.
- GRACE is especially useful for prognostic risk in NSTE-ACS and can support invasive-strategy decisions.
- No risk score should override STEMI, ongoing ischemia, shock, malignant arrhythmia or another immediately dangerous diagnosis.
- For MCCQE questions, disposition follows the highest-risk credible diagnosis: unstable/high-risk patients require monitored inpatient/specialist care; low-risk discharge requires a validated pathway and follow-up plan.
Study Session 2.2 — Chronic Coronary Disease & Stable Angina
Complete MCCQE coronary-disease study review
Core topics & learning goals
- Recognize predictable exertional angina and common anginal equivalents.
- Estimate clinical likelihood of obstructive CAD rather than ordering the same test for every patient.
- Choose exercise ECG, stress imaging, CCTA or invasive angiography based on patient/test characteristics.
- Separate symptom-relieving antianginal therapy from event-preventing therapy.
- Know when persistent symptoms or high-risk anatomy should prompt revascularization assessment.
- Recognize vasospastic angina and microvascular/INOCA presentations.
Clinical recognition & investigation
- Define symptom threshold, change over time, exercise limitation and whether symptoms are truly stable.
- Assess BP, lipids, diabetes, smoking, kidney function, activity, weight, medication adherence and psychosocial barriers.
- Escalate any recent acceleration, rest pain, prolonged episodes or biomarker/ECG evidence into an ACS pathway rather than a stable-angina pathway.
Management & patient-safety priorities
- Use short-acting nitroglycerin for episodic symptom relief when safe and individualized long-term antianginal therapy for recurrent symptoms.
- Use evidence-based vascular risk reduction: lipid lowering, antiplatelet therapy when indicated, BP/diabetes treatment, smoking cessation, exercise and nutrition.
- Refer for coronary anatomy/revascularization assessment when symptoms remain unacceptable despite medical therapy or high-risk disease is suspected.
MCCQE exam traps
- A normal resting ECG does not rule out chronic coronary disease.
- Routine stress testing is not appropriate during active ACS or unstable symptoms.
- Nitrates improve symptoms but are not a substitute for event-preventing treatment.
- Nonobstructive coronary arteries do not prove that ischemic symptoms are “non-cardiac.”
Authoritative sources for this study session
1. Stable angina and chronic coronary disease — core phenotype
- Symptoms are usually reproducible with exertion or emotional stress and improve with rest or nitroglycerin.
- Dyspnea can be an anginal equivalent. The key concept is a relatively stable relationship between myocardial oxygen demand and ischemic threshold.
- If frequency, severity or threshold changes substantially—or pain occurs at rest—reconsider ACS.
2. Clinical likelihood and deciding whether to test
- Use age, sex, symptom characteristics and major risk factors to estimate likelihood of obstructive CAD.
- Very-low-risk patients may not benefit from cardiac testing; higher-risk patients need testing that can meaningfully change management.
- Do not order invasive angiography merely because a patient has risk factors if noninvasive assessment is appropriate and symptoms are stable.
3. Choosing exercise ECG, stress imaging or CCTA
- Exercise ECG: most useful when the patient can exercise adequately and the resting ECG is interpretable.
- Stress imaging: useful when resting ECG limits interpretation, exercise is inadequate or greater ischemic localization/risk information is needed.
- CCTA: provides coronary anatomy and is useful in selected stable patients with appropriate renal function/contrast tolerance and interpretable heart-rate conditions.
- Testing choice should reflect local availability, pretest likelihood, patient factors and the clinical question—not memorization of one universal “best” test.
4. Antianginal medication strategy
- Short-acting nitroglycerin: episodic relief and pre-exertion use; counsel about hypotension and PDE-5 inhibitor interactions.
- Beta-blockers: useful for angina especially when heart rate is elevated or there is another indication; avoid/adjust in marked bradycardia, advanced AV block, shock or severe decompensated HF.
- Calcium-channel blockers: useful alternatives/add-ons; non-dihydropyridines reduce heart rate and can worsen bradycardia/AV block or HFrEF.
- Long-acting nitrates: can improve symptoms; use a nitrate-free interval to limit tolerance and remember they do not replace secondary prevention.
5. Event-preventing therapy in established CAD
- Prioritize high-intensity/maximally tolerated statin therapy and add non-statin therapy when lipid levels remain above guideline thresholds in high-risk secondary prevention.
- Use antiplatelet therapy according to CAD/PCI history and bleeding risk; DAPT is not indefinite for every stable patient.
- Treat hypertension and diabetes with agents selected for overall cardiovascular/renal benefit when indicated.
- Smoking cessation, regular activity, dietary quality, weight management and adherence are active treatments, not optional advice.
6. When revascularization becomes important
- Consider revascularization when angina remains lifestyle-limiting despite guideline-directed therapy.
- Anatomy and LV function matter: left-main disease, complex multivessel disease and selected high-risk patterns require Heart Team/specialist assessment.
- Revascularization may improve symptoms and, in selected anatomy, prognosis; it does not eliminate the need for lipid, BP, antithrombotic and lifestyle treatment.
7. Vasospastic angina
- Typically presents with rest pain and transient ischemic ECG changes due to coronary spasm.
- Calcium-channel blockers and nitrates are key therapies; identify smoking/stimulant exposure and other triggers.
- Do not assume every rest episode with normal coronary anatomy is anxiety or reflux.
8. Microvascular angina / INOCA
- Patients can have ischemic symptoms and objective evidence of ischemia despite no obstructive epicardial CAD.
- Mechanisms include microvascular dysfunction and vasospasm; management combines risk-factor control with phenotype-directed antianginal therapy.
- Persistent symptoms deserve a diagnostic explanation and treatment plan rather than dismissal after a “normal” angiogram.
Study Session 2.3 — NSTEMI / Unstable Angina
Complete MCCQE coronary-disease study review
Core topics & learning goals
- Differentiate NSTEMI, unstable angina, type 2 MI and non-ischemic myocardial injury.
- Recognize dynamic ST depression/T-wave inversion and understand that ECG may initially be normal.
- Use serial high-sensitivity troponin and assay-specific pathways rather than a single universal cutoff/delta.
- Identify recurrent ischemia, shock, acute HF and malignant arrhythmia as very-high-risk features.
- Understand aspirin, P2Y12 therapy, anticoagulation, nitrates, lipid therapy and invasive-strategy principles.
- Balance ischemic benefit against bleeding risk, CKD, anemia, thrombocytopenia and need for oral anticoagulation.
Clinical recognition & investigation
- Search for ongoing/recurrent pain, dynamic ECG change, pulmonary edema, hypotension, new MR, ventricular arrhythmia and other features requiring urgent escalation.
- Look for triggers of type 2 MI such as severe anemia, sepsis, sustained tachyarrhythmia, hypoxemia or severe hypertension/hypotension.
- Use renal function, hemoglobin/platelets, bleeding history and concurrent anticoagulants when choosing antithrombotic therapy.
Management & patient-safety priorities
- Initiate ACS therapy promptly while arranging early invasive assessment for high-risk patients.
- Do not use fibrinolysis for NSTEMI/unstable angina.
- Treat the precipitating cause when type 2 MI is present rather than automatically applying a complete type 1 MI antithrombotic pathway.
- Reassess after every intervention for recurrent ischemia, bleeding, renal deterioration and hemodynamic change.
MCCQE exam traps
- Troponin positivity alone does not tell you the MI mechanism.
- Do not call a chronically elevated stable troponin in advanced CKD an acute NSTEMI without a compatible rise/fall and ischemic evidence.
- Do not give fibrinolysis for isolated ST depression/T-wave inversion NSTE-ACS.
- A low-risk score never overrides recurrent ischemia, shock or malignant arrhythmia.
Authoritative sources for this study session
1. NSTEMI versus unstable angina in the hs-troponin era
- NSTEMI: acute myocardial infarction without persistent diagnostic ST elevation, usually demonstrated by an ischemic presentation plus troponin rise/fall above the 99th percentile.
- Unstable angina: ischemic symptoms without biomarker evidence of acute necrosis; it is less common with sensitive troponin assays but remains clinically relevant.
- Both require risk stratification; high-risk unstable angina can still require invasive evaluation despite negative troponin.
2. NSTE-ACS ECG patterns
- Dynamic horizontal/downsloping ST depression and new symmetric T-wave inversion increase suspicion for ischemia.
- Transient ST elevation may occur and should be treated as high risk.
- Deep anterior T-wave inversion after pain resolves can represent a critical proximal LAD pattern (e.g., Wellens pattern) and should not be sent for routine exercise stress testing.
- Diffuse ST depression with aVR elevation suggests severe global subendocardial ischemia/high-risk disease; it requires urgent specialist assessment but is not a precise “left-main equals” diagnosis.
3. Serial troponin and type 1 versus type 2 MI
- Use the institution/assay-specific accelerated hs-troponin pathway; absolute values and delta criteria differ among assays.
- Type 1 MI: plaque disruption with coronary thrombosis. Type 2 MI: ischemia from supply-demand mismatch such as tachyarrhythmia, severe anemia, hypoxemia, sepsis or extreme BP derangement.
- Treating the underlying trigger is central in type 2 MI; antithrombotic/revascularization decisions depend on the probability of concomitant coronary thrombosis/CAD.
4. Risk stratification and invasive timing
- Immediate/very urgent: hemodynamic instability/shock, recurrent refractory chest pain, life-threatening arrhythmia or mechanical complication.
- High risk: confirmed NSTEMI, dynamic ST/T changes, high GRACE risk or other significant features generally support early invasive evaluation.
- Lower-risk patients may undergo a more selective strategy after structured assessment.
- Exact timing is system-dependent; on exams, physiologic instability outranks a numerical score.
5. Antiplatelet therapy — aspirin and P2Y12 principles
- Aspirin is foundational in suspected/confirmed ACS unless contraindicated.
- A P2Y12 inhibitor is usually added in ACS/PCI, but agent choice and timing depend on invasive strategy, bleeding risk, prior stroke/TIA, need for CABG and concurrent oral anticoagulation.
- Do not memorize “DAPT for everyone forever.” Duration may be shortened, extended or modified according to ischemic and bleeding risk and contemporary CCS guidance.
6. Anticoagulation, nitrates, oxygen and analgesia
- Parenteral anticoagulation is standard in many NSTE-ACS pathways; specific agent/dose depends on strategy, kidney function and local protocol.
- Nitrates relieve ischemic pain and reduce preload; avoid with hypotension, suspected RV infarction/preload dependence or recent PDE-5 inhibitor exposure.
- Oxygen is for hypoxemia/respiratory compromise, not automatic treatment of every normoxemic MI.
- Opioids may be considered for severe refractory pain but can complicate assessment and drug absorption; reperfusion and anti-ischemic therapy are priorities.
7. CKD, anemia, thrombocytopenia and bleeding risk
- CKD increases both ischemic and bleeding risk; adjust renally cleared antithrombotics and interpret chronically elevated troponin using change plus ischemic evidence.
- Severe anemia can trigger type 2 MI and may alter antithrombotic/invasive decisions.
- Active bleeding or significant thrombocytopenia requires individualized cardiology/hematology planning; do not apply a routine DAPT algorithm blindly.
8. MINOCA and mimics after angiography
- MINOCA is a working diagnosis when a patient meets MI criteria but angiography shows no obstructive culprit lesion.
- Potential mechanisms include plaque disruption, spasm, embolism/thrombosis, SCAD and microvascular disease; myocarditis and Takotsubo are important mimics that must be distinguished.
- Cardiac MRI and targeted coronary evaluation can clarify etiology; treatment should be mechanism-directed rather than assuming one pathway fits all.
Study Session 2.4 — STEMI, Reperfusion, Post-MI Complications & Secondary Prevention
Complete MCCQE coronary-disease study review
Core topics & learning goals
- Recognize STEMI and coronary-occlusion patterns quickly enough to activate reperfusion without waiting for biomarkers.
- Localize inferior, RV, posterior, anterior/septal and lateral infarction and anticipate territory-specific complications.
- Understand primary PCI, inter-facility transfer, fibrinolysis and rescue-PCI principles.
- Know major fibrinolysis contraindications and situations where nitrates/preload reduction are unsafe.
- Recognize cardiogenic shock, malignant arrhythmias and mechanical complications by timing, murmur and hemodynamics.
- Plan discharge and long-term secondary prevention after ACS/PCI.
Clinical recognition & investigation
- Use symptoms plus ECG to activate reperfusion; troponin should not delay treatment when the ECG demonstrates acute coronary occlusion requiring emergent intervention.
- In inferior MI, assess for RV involvement and brady/AV block. In large anterior MI, anticipate LV dysfunction, shock and mural-thrombus risk.
- A new murmur, abrupt pulmonary edema, sudden hypotension or PEA days after MI is a mechanical-complication emergency until proven otherwise.
- Recurrent severe chest pain with new ST changes after PCI raises concern for acute stent thrombosis/re-occlusion.
Management & patient-safety priorities
- Primary PCI is preferred when it can be delivered within the recommended regional time window; otherwise eligible early presenters may require fibrinolysis plus transfer according to local STEMI systems.
- Do not give fibrinolysis when major absolute contraindications are present or when aortic dissection is suspected.
- Treat cardiogenic shock with urgent specialist/PCI-team involvement and revascularization of the culprit lesion; use vasoactive/mechanical support selectively.
- Begin secondary prevention before discharge and address medication access, adherence, smoking, exercise and cardiac rehabilitation.
MCCQE exam traps
- Do not wait for troponin confirmation before reperfusion in a clear STEMI/acute coronary occlusion presentation.
- Inferior STEMI + hypotension + elevated JVP + clear lungs suggests RV infarction; nitrates/aggressive diuresis may worsen preload-dependent hypotension.
- New hypotension plus a new holosystolic murmur after MI is not “just recurrent ischemia”—think papillary rupture or VSD.
- Fibrinolysis is not used for NSTEMI and is dangerous in suspected dissection.
Authoritative sources for this study session
1. STEMI recognition and territory localization
- Inferior: II, III, aVF; often RCA, sometimes LCx. Look for reciprocal changes in I/aVL and assess RV involvement.
- Anterior/septal: V1–V4; often LAD. Large anterior infarction carries substantial LV dysfunction/shock risk.
- Lateral: I, aVL, V5–V6; may involve LCx/diagonal branches.
- Interpret ST elevation in contiguous leads with symptoms, reciprocal changes and baseline patterns. New LBBB alone is not an automatic STEMI diagnosis.
2. Right-ventricular infarction
- Suspect with inferior STEMI plus hypotension, elevated JVP and relatively clear lungs.
- Obtain right-sided leads (especially V4R) when clinically relevant.
- Maintain adequate preload and avoid medications that cause dangerous preload reduction when hypotensive; nitrates and aggressive diuresis can worsen shock.
- Treat associated bradycardia/AV block when hemodynamically significant.
3. Posterior infarction
- Reciprocal posterior changes may appear as ST depression with tall R waves in V1–V3.
- Confirm with posterior leads V7–V9 when suspicion is present.
- Posterior MI often accompanies inferior/lateral infarction and should not be mistaken for isolated anterior ischemia.
4. High-risk coronary-occlusion patterns without classic persistent ST elevation
- Dynamic ischemic changes, hyperacute T waves, posterior occlusion, certain de Winter-like patterns and recurrent transient ST elevation can represent acute coronary occlusion/high-risk ischemia.
- Wellens-pattern anterior T-wave changes after pain resolution suggest critical proximal LAD disease; avoid routine exercise stress testing and obtain urgent cardiology evaluation.
- The exam principle is not to memorize every named pattern—it is to recognize ongoing coronary occlusion/high-risk anatomy and escalate promptly.
5. Primary PCI versus fibrinolysis
- Primary PCI: preferred reperfusion when achievable promptly by an experienced system.
- If timely PCI cannot be achieved and the patient is an eligible early-presenting STEMI patient without contraindications, fibrinolysis may be used according to regional protocol followed by transfer to a PCI-capable centre.
- Failed fibrinolysis or persistent ischemia/ST elevation requires rescue PCI; successful lysis still requires an organized pharmaco-invasive strategy.
- For MCCQE, choose the reperfusion method that restores flow fastest safely within accepted system delays.
6. Fibrinolysis contraindications — high-yield safety list
- Major absolute examples: prior intracranial hemorrhage, known intracranial vascular lesion or malignant neoplasm, recent ischemic stroke within the major exclusion window, active internal bleeding, significant recent intracranial/intraspinal surgery or severe closed-head/facial trauma, and suspected aortic dissection.
- Important relative considerations: severe uncontrolled hypertension, recent major surgery/trauma, prolonged traumatic CPR, active peptic ulcer, pregnancy/postpartum and current anticoagulant exposure depending on intensity.
- Exact timing thresholds vary by guideline/protocol; on the exam, recognize the major bleeding/intracranial/dissection exclusions and choose PCI when lysis is unsafe.
7. Cardiogenic shock after MI
- Features include hypotension with end-organ hypoperfusion, cool extremities, oliguria/altered mentation, often elevated filling pressures and pulmonary congestion.
- Urgently identify mechanical complications and perform echocardiographic assessment.
- Culprit-vessel revascularization is central; vasoactive agents and mechanical circulatory support are individualized bridges/support rather than definitive therapy.
- Routine immediate PCI of every non-culprit lesion during shock is not the default strategy; prioritize the culprit and stabilize.
8. Electrical complications after MI
- VT/VF may occur early and require immediate defibrillation/ACLS management.
- Inferior MI can cause sinus bradycardia and AV nodal block; anterior MI-associated high-grade block often reflects extensive septal disease and can be more ominous.
- AF can be triggered by ischemia, atrial pressure/heart failure and stress; treat hemodynamic instability first.
- Correct potassium/magnesium abnormalities and ongoing ischemia when managing ventricular arrhythmias.
9. Mechanical complications — timing and bedside clues
- Papillary-muscle rupture (often posteromedial): typically several days after MI; abrupt pulmonary edema/shock with acute severe MR. Murmur can be soft when shock is severe.
- Ventricular septal rupture: several days after MI; new harsh holosystolic murmur, thrill and rapidly progressive HF/shock.
- Free-wall rupture: sudden tamponade, electromechanical dissociation/PEA or catastrophic collapse.
- All require emergency echocardiography and urgent cardiothoracic/interventional management.
10. Pericarditis, LV aneurysm and mural thrombus
- Early post-MI pericarditis: pleuritic/positional pain and rub in the first few days, usually after a larger transmural infarct.
- Post-cardiac-injury syndrome (Dressler): delayed inflammatory pericarditis, usually weeks later.
- LV aneurysm: persistent ST elevation and dyskinetic scar weeks/months later; may contribute to HF, arrhythmia or thrombus.
- LV thrombus: risk rises after large anterior/apical MI with severe regional akinesis; use echocardiography and anticoagulation decisions according to specialist guidance.
11. Recurrent ischemia, reinfarction and stent thrombosis
- Recurrent chest pain after PCI with new ST elevation or instability is an emergency—consider acute stent thrombosis/re-occlusion and activate urgent catheterization.
- Check adherence to antiplatelet therapy and interactions when stent thrombosis occurs.
- Reinfarction can be difficult to diagnose when troponin is already elevated; use recurrent symptoms, ECG changes and a renewed biomarker rise where relevant.
12. Secondary prevention after ACS — discharge checklist
- Antithrombotic plan: aspirin plus a P2Y12 inhibitor after ACS/PCI unless bleeding risk or another indication changes strategy; document agent and intended duration clearly.
- Lipids: start/continue high-intensity or maximally tolerated statin; intensify with non-statin therapy when secondary-prevention thresholds remain unmet.
- BP/diabetes: control risk factors and use therapies with proven cardiovascular/renal benefit when indicated.
- Cardiac rehabilitation: referral improves recovery, exercise confidence and risk-factor management.
- Lifestyle: smoking cessation, physical activity, heart-healthy diet, weight management and medication adherence.
- Follow-up: assess LV function, HF symptoms, recurrent angina, arrhythmia, bleeding, renal function and ability to afford/take medications.
13. Special ACS presentations — SCAD, stimulants and high-risk groups
- SCAD: consider in younger patients, especially women and pregnancy/postpartum, with ACS but few traditional risk factors. Stable cases are often managed conservatively because PCI can be technically challenging; involve cardiology and evaluate associated arteriopathy as appropriate.
- Stimulants: cocaine/amphetamines can produce vasospasm, severe hypertension and thrombosis. Treat the ACS and sympathetic surge; identify polysubstance use.
- Older adults: balance invasive/antithrombotic benefit with frailty, renal function, cognition and bleeding risk without undertreating solely because of age.
- CKD: dose-adjust medications, minimize contrast injury where possible and interpret troponin trends carefully.
Sources:AHA-ACS-2025
Module 2 — Rapid recognition table
| Finding / presentation | High-yield interpretation |
|---|---|
| Chest pain + shock/arrhythmia/hypoxemia | Stabilize first while simultaneously identifying ACS, dissection, PE, pneumothorax or tamponade. |
| Normal first ECG but persistent ischemic symptoms | Repeat ECG and continue ACS evaluation; a single tracing does not exclude ischemia. |
| Troponin rise/fall + ischemic evidence | Acute MI; then determine type/mechanism and reperfusion/invasive needs. |
| Troponin rise/fall without ischemic evidence | Acute myocardial injury; search for non-ischemic causes. |
| STEMI on ECG | Activate reperfusion; do not wait for troponin. |
| Inferior STEMI + hypotension + high JVP + clear lungs | Think RV infarction; obtain right-sided leads and avoid dangerous preload reduction. |
| ST depression V1–V3 + tall R waves | Consider posterior MI; obtain posterior leads. |
| NSTE-ACS + recurrent pain/shock/VT | Very high risk; urgent invasive assessment. |
| NSTEMI | Do not use fibrinolysis; use antithrombotic therapy and risk-guided invasive management. |
| New pulmonary edema + new murmur 2–7 days after MI | Mechanical complication until proven otherwise—acute MR or VSD; emergency echo/surgical evaluation. |
| Sudden PEA/collapse several days after MI | Consider LV free-wall rupture with tamponade. |
| Stable exertional angina + interpretable ECG + can exercise | Exercise ECG may be appropriate depending on pretest likelihood and local pathway. |
| Persistent angina despite no obstructive CAD | Consider INOCA/microvascular dysfunction or vasospasm; do not dismiss symptoms. |
| Post-PCI severe pain + new ST elevation | Possible acute stent thrombosis/re-occlusion; urgent cath-lab assessment. |
Post-MI complications — high-yield timing
| Typical timing | Complications to recognize |
|---|---|
| Minutes–24 h | VT/VF, bradyarrhythmia/AV block, recurrent ischemia, acute LV failure, cardiogenic shock |
| 1–3 days | Early fibrinous pericarditis; evolving HF/arrhythmias |
| 2–7 days | Papillary-muscle rupture → acute MR; VSD rupture; free-wall rupture → tamponade/PEA |
| Days–weeks | LV thrombus after large anterior/apical infarction; ongoing remodeling/HF |
| Weeks–months | Post-cardiac-injury syndrome (Dressler), LV aneurysm, chronic HF/arrhythmia |
Timing is approximate and complications can overlap. On the MCCQE, the combination of time course, new murmur, pulmonary edema, shock, arrhythmia or tamponade physiology is more important than memorizing an exact day.
Authoritative topic-linked bibliography
- MCC-GUIDE-2026Official MCC2026Medical Council of Canada — Study smarter: A study guide for the MCCQE
Medical Council of Canada. Study smarter: A study guide for the MCCQE. Ottawa: MCC; 2026.
Used for: MCCQE blueprint, preparation framework and Cardiology placement within Medicine study sessions.
- MCC-CHESTOfficial MCC ObjectiveCurrentMCC Examination Objective — Chest pain
Medical Council of Canada. Examination Objectives: Chest pain. Medical Expert role.
Used for: Diagnose cause/severity, exclude life-threatening diagnoses, perform focused assessment and choose urgent investigations/management.
- AHA-CHEST-2021Multisociety guideline2021AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline — Evaluation and Diagnosis of Chest Pain
Gulati M, Levy PD, Mukherjee D, et al. 2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR Guideline for the Evaluation and Diagnosis of Chest Pain. Circulation. 2021;144:e368-e454.
Used for: Acute/stable chest-pain assessment, ECG/troponin pathways, risk stratification and noninvasive test selection.
- AHA-ACS-2025Multisociety guideline2025ACC/AHA/ACEP/NAEMSP/SCAI Guideline — Acute Coronary Syndromes
Rao SV, O'Donoghue ML, Ruel M, et al. 2025 ACC/AHA/ACEP/NAEMSP/SCAI Guideline for the Management of Patients With Acute Coronary Syndromes. Circulation/JACC. 2025.
Used for: Contemporary management of unstable angina, NSTEMI and STEMI including antithrombotic therapy, invasive strategy, reperfusion, cardiogenic shock and secondary prevention.
- CCS-APT-2024Canadian guideline update2024Canadian Cardiovascular Society — Focused Update of the Guidelines for Antiplatelet Therapy
Canadian Cardiovascular Society. Focused Update of the Guidelines for the Use of Antiplatelet Therapy. 2024.
Used for: Canadian antiplatelet selection and DAPT duration after ACS/PCI, including balancing ischemic and bleeding risk.
- CCS-SECONDARY-2026Canadian clinical pathway2026Canadian Cardiovascular Society — Secondary Prevention Pathway after ACS
Canadian Cardiovascular Society. CCS Secondary Prevention Pathway. Updated 2026.
Used for: Post-ACS discharge and longitudinal secondary prevention, including medications, risk factors and follow-up.
- CCS-LIPIDS-2021Canadian guideline2021Canadian Cardiovascular Society Guidelines — Dyslipidemia
Pearson GJ, Thanassoulis G, Anderson TJ, et al. 2021 Canadian Cardiovascular Society Guidelines for the Management of Dyslipidemia for the Prevention of Cardiovascular Disease in Adults. Can J Cardiol. 2021;37:1129-1150.
Used for: Secondary-prevention lipid management and escalation beyond statin therapy.
- AHA-CCD-2023Multisociety guideline2023AHA/ACC/ACCP/ASPC/NLA/PCNA Guideline — Chronic Coronary Disease
Virani SS, Newby LK, Arnold SV, et al. 2023 AHA/ACC/ACCP/ASPC/NLA/PCNA Guideline for the Management of Patients With Chronic Coronary Disease. Circulation. 2023.
Used for: Stable/chronic coronary disease, antianginal therapy, prevention, revascularization and patient-centred management.
- AHA-REVAS-2021Multisociety guideline2021ACC/AHA/SCAI Guideline — Coronary Artery Revascularization
Lawton JS, Tamis-Holland JE, Bangalore S, et al. 2021 ACC/AHA/SCAI Guideline for Coronary Artery Revascularization. Circulation. 2022;145:e18-e114.
Used for: PCI/CABG selection and revascularization principles for acute and chronic coronary disease.
Evidence review: August 19, 2026. BoardQBank study organization is educational and is not an official MCC course. Official MCC objectives determine the examination framework; Canadian specialty guidance is prioritized, with major multisociety guidelines used for current ACS/chest-pain technical standards.