cardio

Cardiovascular Diseases

  • Categories of Cardiovascular Diseases
    • Coronary Heart Disease:
    • Affects coronary vessels on the surface of the heart.
      • Angina Pectoris:
      • Chest pain, can indicate a heart attack but not always.
      • Myocardial Infarction:
      • Clinical term for a heart attack.
      • Heart Failure:
      • Condition where the heart fails to pump sufficiently.
    • Cerebrovascular Disease:
    • Affects vessels in the brain.
      • Examples include strokes and Transient Ischemic Attacks (TIAs) or mini strokes.
    • Peripheral Artery Disease:
    • Affects arteries in the extremities, causing blockages.
    • Aortic Atherosclerotic Disease:
    • Affects the aorta, major artery in the trunk.
      • Includes aneurysms (widening) and aortic dissection (rupture).

Atherosclerosis

  • Definition:
    • A chronic inflammatory disease causing various cardiovascular diseases.
  • Pathophysiology:
    • Progressive accumulation of plaques in arteries.
    • Plaques consist of:
    • Lipids
    • Smooth muscle cells
    • Macrophages (engulfed lipids)
    • Connective tissues
  • Potential Outcomes:
    • Complete vessel occlusion leading to thrombosis (blockage) and plaque rupture.
    • Ischemia: Tissue lacking oxygen and nutrients leading to stress.
    • Infarction: Cellular death due to prolonged ischemia.

Acute Coronary Syndrome (ACS)

  • Class Definition:
    • A type of coronary heart disease characterized by the following:
    • Cause: Cardiac ischemia (lack of oxygen to heart tissues).
    • Symptoms:
      • Classic symptoms: Angina (chest pain), squeezing pressure, difficulty breathing.
      • Non-classic symptoms (more common in women): Stabbing/sharp chest pain, nausea, shortness of breath, abdominal pain.
    • Types of Angina:
      • Stable Angina: Predictable, occurs during exertion, relieved by rest.
      • Unstable Angina: New or worsening chest pain at rest, indicating severe blockage.
    • Event: Acute Myocardial Infarction (heart attack).

Diagnosis of Cardiac Events

  • Role of Clinical Assessment:
    • Physical exam to distinguish between myocardial ischemia and non-cardiac causes (e.g., reflux, anxiety).
    • Tests Involved:
    • Electrocardiogram (EKG/ECG): Analyzes electrical signals in the heart.
      • Terms such as non-ST elevation MI (NSTEMI) and ST elevation MI (STEMI) are derived from this test.
    • Chest X-ray: Determines if pain is cardiac-related or linked to other conditions (e.g., pneumonia, pneumothorax, aortic dissection).
    • Lab Tests: Cardiac biomarkers used to diagnose myocardial infarctions.

Ideal Cardiac Marker Characteristics

  • Specific to cardiac tissue.
  • Rises quickly post heart attack.
  • Remains elevated for an extended time.
  • Proportional correlation to the severity of cardiac events.
  • Simple to measure with minimal interference.

Cardiac Biomarkers

  • Categories:
    • Markers of Cardiac Damage:
    • Aspartate Aminotransferase (AST):
      • Early cardiac marker, not specific to heart. Found in liver, muscles, kidneys.
    • Lactate Dehydrogenase (LD/LDH):
      • Sensitive, remains elevated longer. Not specific — often used historically.
      • LD1 is specific to myocardium; LD5 relates to skeletal muscle/liver.
    • Creatine Kinase (CK):
      • Useful post myocardial infarction; rises in 6-8 hours, peaks in 24 hours.
      • CKMB specific to myocardium.
      • Declining use for CKMB as newer tests are available.
    • Cardiac Troponins (I, T, C):
      • Key marker for MI; increases by 10x normal limit; detectable 3-12 hours after an event.
      • Peaks at 12-24 hours; remains elevated for about 14 days.
    • Myoglobin:
      • Muscle oxygen-carrying protein; rises rapidly post injury but lacks specificity.
    • Markers of Heart Failure:
    • Heart failure leads to decreased pumping function.
    • Symptoms: shortness of breath, fatigue, swelling.
    • B-type Natriuretic Peptide (BNP):
      • Released in response to heart pressure/volume overload; aids in diagnosing dyspnea causes.
    • N-terminal proBNP (NT-proBNP):
      • Precursor of BNP; preferred measurement form due to longer half-life and stable concentrations.
    • Cardiac Risk Markers:
    • Myeloperoxidase (MPO):
      • Released from neutrophils; indicates oxidative stress and plaque instability.
    • High-Sensitivity C-Reactive Protein (hs-CRP):
      • Inflammatory marker, indicates cardiac risk severity but lacks diagnostic value.
    • Measurement ranges:
      • < 1 mg/dL: Low risk
      • 1-3 mg/dL: Moderate risk
      • > 3 mg/dL: High risk
    • Homocysteine:
      • Amino acid linked to arterial damage, promoting atherosclerosis.
    • Pulmonary Embolism Marker:
    • D-dimer:
      • Breakdown product of clotting; elevated in PE but can arise from various conditions.
      • A negative D-dimer makes PE unlikely, whereas a high value does not confirm a PE.

Conclusion

  • Summary charts presented but not necessary for memorization, showcasing historical vs. current utilization of various biomarkers for different cardiac conditions.

  • Importance of accurate diagnosis and understanding roles of different markers in clinical practice emphasized throughout the lecture.

  • Thank you for your attention!