Cardiovascular Diseases: Myocardial Infarction Symptoms

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Questions and Answers

What percentage of MI cases are silent or atypical?

40%

10%

20% (correct)

30%

Which of the following is NOT a sign of heart failure?

Asymmetric BP (correct)

Cool extremities

Lung crackles + S3

HoTH

What is a common finding in patients with ischemia?

Tachycardia

Diaphoresis (correct)

Hypertension

Hypotension

What is the preferred biomarker for diagnosing ACS?

cTn Signup and view all the answers

What is a key feature of high-likelihood ACS?

All of the above Signup and view all the answers

What is a common symptom of ACS in females, elderly, and diabetic patients?

Epigastric pain without chest pain Signup and view all the answers

What is a common acute anti-ischemic measure?

All of the above Signup and view all the answers

What is the primary goal of the ECG in triaging ACS?

To detect signs of ischemia Signup and view all the answers

Which of the following is a characteristic of stable angina?

No plaque ulceration and no thrombus Signup and view all the answers

What is the difference between unstable angina and non-ST elevation myocardial infarction (NSTEMI)?

Cardiac biomarkers are elevated in NSTEMI Signup and view all the answers

What is the primary mechanism of acute coronary syndrome (ACS)?

Rupture of atherosclerotic plaque Signup and view all the answers

What is the most common cardiac biomarker used in the diagnosis of ACS?

Troponin I Signup and view all the answers

What is the time frame for troponin I to increase after a myocardial infarction?

2-4 hours Signup and view all the answers

Which of the following is a characteristic of atherosclerotic plaques prone to disruption?

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

What is the duration of elevation of troponin I after a myocardial infarction?

Weeks Signup and view all the answers

Which of the following is a characteristic of transmural ischemia?

Occurrence with complete 100% flow obstruction Signup and view all the answers

What is the main objective of treatment in STEMI?

Open the artery (revascularization) Signup and view all the answers

What is the contraindication for thrombolysis in a patient with a history of ischemic stroke?

Ischemic stroke < 3 months Signup and view all the answers

What is the effect of inferior MI on the vagal nerve?

Stimulates the vagal nerve Signup and view all the answers

What is the purpose of aspirin in the treatment of STEMI?

To inhibit platelet aggregation Signup and view all the answers

What is the loading dose of clopidogrel?

300-600 mg Signup and view all the answers

What is the effect of beta blockers on the heart?

Reduce oxygen demand Signup and view all the answers

What is the purpose of nitrates in the treatment of STEMI?

To reduce oxygen demand Signup and view all the answers

What is the effect of occlusion of the RCA?

Cause RV infarction Signup and view all the answers

What is the type of heparin that can be used with fibrin-specific lytics?

UFH Signup and view all the answers

What is the purpose of GP IIb/IIIa inhibitors?

To inhibit platelet activation Signup and view all the answers

Study Notes

Acute Coronary Syndrome (ACS)

New-onset, crescendo, refractory, and post-MI/PCI types of ACS
Associated symptoms:
- Pallor, diaphoresis
- N/V, dyspnea
- Palpitations or light-headedness

Silent or Atypical MI

~20% of MIs are silent or atypical
Atypical symptoms may include N/V, epigastric pain without chest pain
More common in females, elderly, DM, and inferior ischemia

Physical Exam

Signs of ischemia:
- Diaphoresis
- S4
- Paradoxical S2
- New MR murmur (papillary muscle dysfunction)
Signs of HF:
- HoTH
- Cool extremities
- Increased JVP
- Lung crackles and S3
Signs of other vascular disease:
- Asymmetric BP
- Carotid/femoral bruits
- Decreased distal pulses

Approach to Triage

ECG:
- Within 10 minutes of presentation
- After 15-30 minutes
- Repeat 6-12 hours later if clinical changes occur
Cardiac biomarkers:
- cTn (preferred over CK-MB) at presentation and after 3-6 hours
- Repeat 6-12 hours later if clinical or ECG changes occur
If ECG and cTn remain normal and low likelihood of ACS, search for alternative causes
If intermediate likelihood of ACS, rule out UA with stress test or CTA

Acute Anti-Ischemic/Analgesic/Anti-Thrombotic Measures

NTG (SL or IV)
β-blockers
± Oxygen
± Morphine
Aspirin/Heparin

Likelihood of Acute Coronary Syndromes

High likelihood:
- Any of the following:
  - Chest/L arm pain
  - Reproducing pain
  - Documented angina
  - History of CAD (including MI)
Intermediate likelihood:
- NO high features BUT any of the following:
  - Chest/L arm pain
  - Male
  - >70 years old
  - DM
Low likelihood:
- NO high/intermediate features BUT may have:
  - Probable ischemic symptoms in absence of any intermediate features
  - Recent cocaine use

Definition of Acute Coronary Syndrome

Spectrum of clinical presentations, including UA, NSTEMI, and STEMI
UA/NSTEMI differentiated from STEMI by absence of STE
Presentation of UA/NSTEMI similar, but in patients with NSTEMI, evidence of myocardial necrosis (cardiac biomarkers) is present

Extent of Ischemia

Transmural ischemia:
- Occurs with complete 100% flow obstruction (STEMI)
Subendocardial ischemia:
- Occurs with flow obstruction but some distal blood flow
- Stable angina, unstable angina, and NSTEMI

Biomarkers

Cardiac biomarkers:
- Biomarkers spill into blood with cardiac injury
- Most common marker used: troponin I/T
- Increase 2-4 hours after MI
- Stay elevated for weeks
- CK-MB also used
- Increase 4-6 hours after MI
- Normalize within 2-3 days

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Description

This quiz covers the symptoms and signs associated with myocardial infarction, including angina, silent or atypical MI, and physical exam signs.