CVS Grg

Ischemic Heart Disease

  • Definition: A condition characterized by reduced blood flow to the heart muscle, leading to insufficient oxygen supply.

Types of Ischemic Heart Disease:

  1. Coronary Artery Disease (CAD)
  2. Angina Pectoris
  3. Myocardial Infarction (MI)

Angina Pectoris

  • Description: Severe chest pain due to inadequate blood supply to the heart muscle.
  • Causes Agitation and discomfort, indicating ischemia.

Types of Angina:

  1. Classical (Stable) Angina
    • Triggered by exertion or stress.
  2. Unstable Angina
    • Occurs at rest or with increased frequency/intensity.
  3. Variant (Prinzmetal) Angina
    • Caused by vasospasm of coronary arteries.

Pathophysiology:

  • Plaque formation in blood vessels narrows arteries, impeding blood flow, which prevents the heart from receiving adequate oxygen.
  • Mechanism of Action:
    • At rest: Body dilates blood vessels to maintain flow.
    • During exertion: Blood vessels should further dilate; however, in CAD, they can't due to existing conditions.

Symptoms:

  • Chest Pain: Described as sensation of pressure or squeezing.

Treatment for Angina

Goals:

  1. Decrease heart workload.
  2. Increase blood flow.

Pharmacological Agents:

  1. Nitrates
    • Induces vasodilation.
    • Examples: Glyceryl Trinitrate (GTN), Isosorbide Dinitrate (ISDN).
    • Mechanism:
    • Release of nitric oxide (NO) leading to vascular smooth muscle relaxation.
    • Side effects: Headache, tolerance with frequent doses (requires a nitrate-free interval of 6-8 hours).
  2. Calcium Channel Blockers (CCB)
    • Example: Diltiazem, Amlodipine.
    • Mechanism: Prevents calcium influx, causing dilation of blood vessels and decreasing heart rate.
    • Side Effects: Headache, constipation, gum hypertrophy.
  3. Beta-Blockers
    • Examples: Metoprolol, Carvedilol.
    • Mechanism: Reduce heart rate and contractility, decreasing workload.
  4. Anti-spasmodics for variant angina.
  5. Sildenafil (Tadalafil): Caution when combining with nitrates due to the risk of hypotension.

Non-Pharmacological Treatments:

  • Lifestyle changes: Diet, exercise, and smoking cessation.

Myocardial Infarction (MI)

  • Definition: A heart attack resulting from prolonged ischemia leading to death of heart muscle tissue.

Symptoms:

  • Severe chest pain, often radiating to shoulders, neck, arms, jaw.
  • Nausea, sweating, shortness of breath.
  • Diagnostic markers: Elevated Troponin levels indicate myocardial damage.

Types of MI Based on ECG:

  1. STEMI: ST-segment Elevation Myocardial Infarction
    • Full thickness heart muscle damage
  2. Non-STEMI: Partial thickness damage.

Treatment Strategy:

  1. Immediate Treatments:

    • Morphine, Nitrates, Aspirin to relieve pain and prevent clotting.
    • Thrombolytics (e.g., Streptokinase) to dissolve clots.

  2. Chronic Management:

    • Antiplatelet agents (Clopidogrel).
    • Beta-blockers for cardioprotection.
    • Statins for cholesterol management.

Special Circumstances & Treatment:

  • Heart Failure: Inadequate blood flow to tissues despite normal or elevated cardiac output.
  • Pharmacological management includes diuretics and inotropic agents (e.g., Dopamine, Dobutamine)

Congestive Heart Failure (CHF)

  • Definition: A condition where the heart cannot pump sufficient blood to meet the body's needs.

Types of CHF:

  1. Systolic Dysfunction
  2. Diastolic Dysfunction

Management Goals:

  1. Fluid management: Diuretics (e.g., Furosemide).
  2. Increase contractility: Inotropic drugs (e.g., Digoxin).
  3. Control heart rate: Beta-blockers and CCB.

Treatment Overview:

  1. Diuretics: Loop diuretics (Furosemide) to relieve edema.
    • Side Effects: Electrolyte imbalance (hypokalemia).
  2. Inotropics: Increasing cardiac contractility with agents (Dopamine).

Additional Drug Classes in Cardiology

  1. ACE Inhibitors

    • Example: Lisinopril, Enalapril.
    • Mechanism: Block conversion of Angiotensin I to II, causing vasodilation, reducing preload & afterload.
    • Side Effects: Cough, angioedema.

  2. Angiotensin Receptor Blockers (ARBs)

    • Example: Losartan, Valsartan.
    • Similar action to ACE inhibitors with fewer side effects.

  3. Direct Vasodilators

    • Example: Hydralazine, Nitroprusside used in hypertensive emergencies.

  4. Beta-Blockers: Control heart rate and reduce blood pressure. Example: Atenolol.

Renin-Angiotensin-Aldosterone System (RAAS)

  • Overview: Critical in blood pressure regulation.
  • Inhibition of RAAS lowers blood pressure and decreases workload of heart, useful in treating hypertension and heart failure.

Conclusion

  • Understanding ischemic heart diseases, angina, myocardial infarction, and heart failure aids in the development of effective treatment strategies to manage heart conditions and improve patient outcomes.