Stable Angina Lecture Notes

Overview of Stable Angina

• Substernal chest pain occurring during exertion.
  • May radiate to neck and jaw.
  • Relieved by rest.
• Importance: Mimics myocardial infarction (MI).

Diagnosis

• Stress Test (physical or chemical):
  • Induces chest pain for evaluation.
  • Changes noted in the ST segment on ECG.
• ECG Observations: ST Segment
  • Isoelectric post-QRS complex normally.
  • ST depression during exertion indicates strain.

Treatment

• Nitroglycerin: Administered to decrease preload via vasodilation.

Unstable Angina

• Major occlusion due to atherosclerosis.
• Previously known as Prinzmetal or vasospasm angina.
  • Now commonly referred to as vasospasm angina.

Progression: Stable to Unstable Angina

• Crescendo pattern leading to MI.
• Non-ST Elevation Myocardial Infarction (Non-STEMI)
  • ST depression might occur.
  • No elevation in cardiac enzymes.

Cardiac Enzymes

• Gold Standard: Troponin I
  • Not elevated in unstable angina.

Symptoms Comparison

• Stable Angina:
  • Pain during exertion.
  • Relief with rest or nitroglycerin.
• Unstable Angina:
  • Pain at rest.
  • Lasts about 30 minutes.
  • Requires aggressive treatment.

ECG Changes

• Stable Angina:
  • Induced ST depression during stress.
  • Focus on leads v4, v5, v6 (Lateral side of heart).
  • Coronary artery involved: Left circumflex.
• Comparison of Enzymes:
  • In stable angina: Cardiac enzymes are normal.
  • In unstable angina: Cardiac enzymes are negative, but still present risk.

Summary

• Difference between stable and unstable angina lies in symptoms at rest and cardiac enzyme levels.
• Key indicator for both is the ST segment changes on an ECG.

Remember to differentiate based on ECG patterns and enzyme tests for effective diagnosis and treatment planning.