BP104T • Unit 3Topic 3 of 3⏱ 5 Min Read
3. Pathophysiology of Major Cardiovascular Disorders
💡 Core Concept & Clinical Context:
Cardiovascular diseases are the leading cause of global mortality. Understanding the cellular and hemodynamic pathophysiological mechanisms of Hypertension, Atherosclerosis, Ischemic Heart Disease (Angina & Myocardial Infarction), and Heart Failure is essential for rational pharmacotherapy.
Clinical Scenarios & Pharmacopoeial Examples:
1Mechanistic Overview of 4 Primary Cardiovascular Pathologies
Cellular mechanisms, clinical symptoms, and drug targets.
Step-by-Step Breakdown:
•1. Essential Hypertension:
•• Etiology: Chronic elevation of Total Peripheral Resistance (TPR) and arterial stiffness; hyperactivity of Renin-Angiotensin-Aldosterone System (RAAS) and sympathetic tone.
•• Pathophysiology: Endothelial dysfunction -> Reduced nitric oxide (NO) bioavailability -> Smooth muscle hypertrophy -> Arteriosclerosis -> Organ damage (left ventricular hypertrophy, nephrosclerosis, stroke).
•2. Atherosclerosis (Plaque Formation):
•• Endothelial injury (smoking, hypertension, hyperglycemia) -> Circulating LDL penetrates intima -> Oxidized to ox-LDL.
•• Monocytes adhere and migrate into intima -> Differentiate into Macrophages -> Ingest ox-LDL via scavenger receptors to become lipid-laden Foam Cells.
•• Foam cells form 'Fatty Streaks' -> Smooth muscle cells proliferate and secrete collagen -> Form a Fibrous Cap covering a necrotic lipid core.
•• Plaque rupture exposes thrombogenic lipid core -> Instant platelet aggregation and thrombosis -> Total arterial occlusion.
•3. Angina Pectoris vs. Myocardial Infarction (MI):
•• Angina: Transient myocardial ischemia where oxygen demand exceeds supply without permanent myocyte necrosis (Stable vs Unstable).
•• STEMI (ST-Elevation MI): Complete transmural thrombotic occlusion -> Prolonged ischemia (> 20 min) causes irreversible coagulative necrosis of myocardium. Biomarkers: Cardiac Troponin I (cTnI) and CK-MB elevation.
•4. Congestive Heart Failure (CHF):
•• Inability of heart to pump sufficient cardiac output to meet metabolic tissue demands.
•• Compensatory RAAS and sympathetic activation cause fluid retention (preload overload) and systemic vasoconstriction (afterload overload), leading to progressive ventricular remodeling, pulmonary edema, and peripheral edema.
Comparison & Reference Table:
| Disorder | Core Hemodynamic Defect | Key Diagnostic Biomarkers / Signs | First-Line Pharmacotherapy Classes |
|---|---|---|---|
| Hypertension | Elevated SVR and arterial stiffening | BP >= 140/90 mmHg, LVH on ECG | ACE inhibitors, ARBs, CCBs, Thiazide diuretics |
| Atherosclerosis | Intimal fibro-fatty plaque accumulation | Elevated hs-CRP, LDL-C > 100 mg/dL | HMG-CoA reductase inhibitors (Statins), Aspirin |
| Myocardial Infarction | Transmural ischemic myocyte necrosis | ST elevation, Elevated Cardiac Troponin I / CK-MB | Thrombolytics (tPA), Antiplatelets, Beta-blockers, PCI |
| Congestive Heart Failure | Inadequate cardiac output (EF < 40%) | Elevated BNP / NT-proBNP, pulmonary rales | ARNI (Sacubitril/Valsartan), Beta-blockers, SGLT2i, Spironolactone |
📋Key Takeaways & Exam Highlights
- Cardiac Biomarkers for MI: Cardiac Troponin I (cTnI) and Troponin T (cTnT) are highly specific and remain elevated for 7-10 days; CK-MB peaks at 24 hours.
- Atherosclerosis Progression: Endothelial injury $\rightarrow$ LDL Oxidation $\rightarrow$ Macrophage Foam Cells $\rightarrow$ Fatty Streak $\rightarrow$ Fibrous Cap Plaque $\rightarrow$ Rupture & Thrombosis.
- Systolic Heart Failure: Reduced ejection fraction ($EF < 40\%$) due to impaired contractility.
🇮🇳 हिन्दी व्याख्या (3. Pathophysiology of Major Cardiovascular Disorders)
एथेरोस्क्लेरोसिस में धमनियों में वसा और फोम कोशिकाओं की परत जम जाती है। जब यह परत फटती है तो खून का थक्का बनकर हार्ट अटैक (Myocardial Infarction) कराता है। हार्ट अटैक की पुष्टि कार्डियक ट्रोपोनिन (Troponin I) टेस्ट से होती है।