Overview of Coronary Artery Disease

1. Overview

Coronary artery disease (CAD), also known as ischemic heart disease (IHD), involves an imbalance between myocardial oxygen demand and supply causing myocardial ischemia. This occurs primarily due to coronary artery problems affecting oxygen delivery. CAD manifests as angina (stable and unstable), acute coronary syndrome (ACS), myocardial infarction (MI), sudden death from arrhythmias, and heart failure. The heart’s coronary arteries supply oxygenated blood; pathologies reduce this supply below myocardial demand, especially during exercise or stress. Diagnosis involves clinical assessment, ECG, cardiac enzymes, imaging, and catheterization. Treatment includes pharmacological measures and revascularization procedures such as angioplasty and coronary artery bypass grafting (CABG).

2. Core Concepts & Key Elements

Normal Physiology of Myocardial Oxygen Supply and Demand
- Balance between oxygen demand and supply
- Rest: Demand = Supply = 3 Oxygen /sc (seconds)
- Exercise: Demand = Supply = 9 Oxygen /sc due to increased coronary flow
Ischemic Heart Disease Manifestation
- Imbalance: myocardial demand exceeds supply → ischemia
- Rest: Demand = Supply = 3 Oxygen /sc → asymptomatic
- Exercise with pathological artery: Demand = 9 Oxygen /sc, Supply = 4 Oxygen /sc → angina
Pathophysiology of Imbalance
- Reduction of coronary blood flow:
  - Organic stenosis (95%): atherosclerosis
  - Functional stenosis (5%): vasospasm (spontaneous/drug-induced)
  - Coronary embolism
- Increased oxygen demand:
  - Tachycardia
  - Hypertension or ventricular hypertrophy
Coronary Arteries Anatomy
- Right coronary artery (RCA), Left coronary artery (LCA)
- Left circumflex artery (LCX), Left anterior descending artery (LAD), etc.
Clinical Manifestations
1. Stable Angina (exertional)
2. Acute Coronary Syndrome (ACS): unstable angina, acute MI
3. Sudden death from arrhythmias
4. Heart failure
Symptoms of Ischemic Heart Disease
- Chest pain: retrosternal/precordial
- Radiation: left axilla, arm, shoulder, jaw
- Nature: constriction, pressure, heaviness

Stable Angina vs. ACS

Feature	Stable Angina	ACS (Unstable Angina/AMI)
Pathophysiology	Partial stenosis, stable plaque	Unstable plaque rupture causing total ischemia
Pain	Typical	Typical ± nausea, vomiting, sweating
Duration	< 20 minutes	> 30 minutes
Occurrence	Exercise/stress	With or without exercise (resting)
Relief	Rest/nitroglycerin	No relief with rest or vasodilators
ECG	Normal or T inversion	T inversion, ST changes, deep Q in MI
Enzymes	No necrosis or enzyme increase	Necrosis with enzyme increase in MI

Diagnostic Approach
- Exercise test (ergometry)
- Coronary CTA or MSCT
- Cardiac catheterization (coronariography)
Therapy
- Pharmacological: Nitroglycerin, antiplatelets, anticoagulants, fibrinolytics
- Non-pharmacological: PTCA, stents, CABG surgery

3. High-Yield Facts

Definitions:
- Ischemic Heart Disease: imbalance between myocardial oxygen demand and supply.
- Stable angina: chest pain on exertion due to partial coronary stenosis.
- ACS: unstable angina or MI from unstable plaque rupture.
Values:
- Myocardial oxygen demand & supply at rest = 3 Oxygen/sc.
- During exercise, demand & supply increase to 9 Oxygen/sc.
- Pathological artery supply reduced to 4 Oxygen/sc during exercise.
Mechanisms:
- 95% organic stenosis (atherosclerosis).
- 5% vasospasm (functional non-organic stenosis).
- Embolism can block coronary artery.
Clinical relevance:
- Typical angina pain is retrosternal, radiates to arm, shoulder, jaw.
- Pain quality: pressure, heaviness, constriction.
- ECG changes: T inversion (ischemia), ST elevation (injury), deep Q waves (necrosis).
- Cardiac enzymes: Troponin and CPK/CK elevated in MI only.
Diagnostic tools correlate with clinical staging and management.

4. Summary Table

Concept	Key Points	Notes
Normal oxygen supply-demand	Equal at rest and exercise, matched by coronary flow	3 oxygen/sc at rest, 9 oxygen/sc at exercise
Pathophysiology	Decreased flow or increased demand causes imbalance	Organic stenosis most common
Symptoms	Chest pain retrosternal/precordial, radiating	Constriction, pressure, heaviness
Stable angina	Partial stenosis, effort-induced pain, short duration	Relieved by rest/nitroglycerin
ACS	Plaque rupture, total ischemia, prolonged pain	Not relieved by rest, enzyme rise
Diagnosis	ECG, enzymes, imaging, catheterization	Exercise test positive in stable angina
Therapy	Pharmacological and revascularization	PTCA, stents, CABG

5. Mini-Schema (ASCII)

Coronary artery disease (IHD)
 ├─ Normal physiology
 │   ├─ Oxygen demand = supply at rest and exercise
 ├─ Pathophysiology
 │   ├─ Reduced coronary flow: atherosclerosis, vasospasm, embolism
 │   └─ Increased demand: tachycardia, hypertension, hypertrophy
 ├─ Clinical manifestations
 │   ├─ Stable angina
 │   ├─ Acute coronary syndrome: unstable angina, MI
 │   ├─ Arrhythmias (sudden death)
 │   └─ Heart failure
 ├─ Symptoms
 │   ├─ Chest pain: retrosternal, irradiating
 │   └─ Quality: constriction, pressure, heaviness
 ├─ Diagnosis
 │   ├─ Symptoms
 │   ├─ ECG changes
 │   ├─ Cardiac enzymes
 │   ├─ Exercise test
 │   └─ Imaging and catheterization
 └─ Therapy
     ├─ Pharmacological: nitroglycerin, antiplatelets
     └─ Non-pharmacological: angioplasty, stents, CABG

6. Rapid-Review Bullets

CAD = myocardial ischemia from oxygen demand-supply mismatch.
Rest oxygen demand & supply = 3 Oxygen/sec; exercise = 9 Oxygen/sec.
Stable angina pain < 20 min, provoked by exertion, relieved by rest.
ACS pain > 30 min, can occur at rest, not relieved by nitroglycerin.
95% coronary stenosis caused by atherosclerosis.
5% due to vasospasm or embolism.
ECG: T wave inversion (ischemia), ST elevation (injury), deep Q (necrosis).
Troponin and CPK increase only in MI.
Exercise test detects exercise-induced ischemia.
Coronary CTA and catheterization visualize stenosis.
Pharmacology: vasodilators, antiplatelets, anticoagulants.
PTCA and stents restore blood flow.
CABG: arterial bypass grafting in severe disease.
Typical angina pain location: retrosternal, radiating to arm, shoulder, jaw.
Pathology stops coronary flow increase needed during exertion.
Arrhythmias cause sudden death in IHD.
Heart failure as a long-term IHD complication.

1. 📌 Essentials

CAD/IHD results from an imbalance of myocardial oxygen supply and demand.

Stable angina is exertional chest pain relieved by rest/nitroglycerin.

Unstable angina and MI are forms of acute coronary syndrome with prolonged, unrelieved pain.

Atherosclerosis (95%) is the main cause of coronary stenosis.

Vasospasm (5%) causes functional restenosis; embolism can occlude arteries.

Typical angina: retrosternal, radiates to arm, jaw, shoulder; constrictive or heavy sensation.

ECG changes: T wave inversion (ischemia), ST elevation (injury), Q waves (necrosis).

Cardiac enzymes (Troponin, CPK) rise during MI but not in stable angina.

Coronary angiography confirms stenosis location and severity.

Revascularization: PTCA, stents, CABG; pharmacotherapy includes nitrates, antiplatelets, anticoagulants.

Rest: myocardial oxygen demand and supply are balanced at 3 Oxygen/sec; exercise raises demand to 9 Oxygen/sec, demand-supply mismatch causes ischemia.

2. 🧩 Key Structures & Components

Coronary arteries — supply oxygenated blood to myocardium.

Left coronary artery (LCA) — includes LAD and LCX, supplies left heart.

Right coronary artery (RCA) — supplies right heart tissues.

Atherosclerotic plaque — narrows lumen, causes stenosis.

Vasospasm — functional constriction of coronary vessels.

Myocardium — tissue affected by ischemia or infarction.

ECG leads — detect electrical changes due to ischemia/injury.

Cardiac enzymes — biomarkers for myocardial necrosis.

3. 🔬 Functions, Mechanisms & Relationships

Normal Heart Physiology:

Contraction depends on adequate oxygen supply.
Supply relies on coronary lumen patency and flow.
Demand increases with exercise; supply adjusts via coronary vasodilation.

Pathophysiology of Ischemia:

Organic stenosis (atherosclerosis) reduces flow; causes ischemia during increased demand.
Vasospasm constricts arteries temporarily; causes spasm-induced ischemia.
Embolism blocks flow acutely, leading to sudden ischemia.

Clinical Manifestation:

Imbalance during exertion → angina.
Plaque rupture → thrombus formation → ACS.

ECG & Biomarkers:

Ischemia: T wave inversion.
Injury: ST elevation.
Infarction: Q waves, enzyme elevation.

Revascularization:

Restores flow in stenosed arteries.
Pharmacotherapy alleviates symptoms and prevents progression.

4. Comparative Table for Angina and MI

Feature	Stable Angina	Unstable Angina / MI
Pathophysiology	Partial stenosis, stable plaque	Plaque rupture, thrombosis, total occlusion
Pain duration	< 20 minutes	> 30 minutes
Trigger	Exercise/stress	Rest or minimal exertion
Relief	Rest or nitroglycerin	No relief; persistent pain
ECG findings	T wave inversion, normal or ST depression	ST elevation (injury), Q waves, T inversion
Enzyme levels	Usually normal; no necrosis	Elevated Troponin, CPK/CK
Symptoms	Retrosternal, exertional angina	Prolonged pain, may radiate, nausea, sweating

5. 🗂️ Hierarchical Diagram

Coronary Artery Disease (CAD / IHD) ├─ Normal Myocardial Oxygen Physiology │ ├─ Rest: demand = supply = 3 oxygen/sec │ └─ Exercise: demand = supply = 9 oxygen/sec ├─ Pathological Causes of Imbalance │ ├─ Organic stenosis (atherosclerosis) - 95% │ ├─ Functional spasm - 5% │ └─ Embolism ├─ Clinical Manifestations │ ├─ Stable angina │ ├─ Unstable angina (ACS) │ ├─ Myocardial infarction │ └─ Sudden arrhythmic death ├─ Symptoms │ ├─ Chest pain: retrosternal, radiates │ └─ Quality: constrictive, like pressure └─ Diagnostic & Treatment Strategies ├─ ECG & enzyme tests ├─ Imaging and catheterization └─ Pharmacological and surgical revascularization

6. ⚠️ High-Yield Pitfalls & Confusions

Confusing stable vs. unstable angina—duration and relief differ.

Mistaking ST depression for infarction (which shows ST elevation).

Assuming all chest pain is cardiac—exclude GI or musculoskeletal causes.

Not recognizing that enzyme elevation (Troponin) confirms infarction specifically.

Believing vasospasm always causes pain during exertion—sometimes occurs at rest.

Confusing angina location with other causes of chest pain.

Overlooking that stable angina does not cause enzyme elevation.

Mistaking Q waves development as total infarction; early MI may have no Q waves.

Assuming angiography is always required for diagnosis—initial assessment may be clinical/ECG.

7. ✅ Final Exam Checklist

Understand the concept of myocardial oxygen demand and supply.

Know the common causes of coronary artery stenosis and spasm.

Distinguish between stable angina, unstable angina, and MI.

Recognize typical chest pain features and radiation.

Correlate ECG changes with ischemic/infarctive stages.

Know key cardiac enzymes and their significance.

Be familiar with diagnosis tools: ECG, enzymes, angiography, imaging.

Know pharmacological treatments: nitrates, antiplatelets, anticoagulants.

Understand revascularization options: PTCA, stents, CABG.

Remember the pathophysiological basis of sudden death in arrhythmias.

Be aware that exercise testing helps detect ischemia.

Know the role of vasospasm and embolism in CAD.

Recognize the importance of lifestyle modification and risk factor control.

Know the typical presentation and location of anginal pain.

Familiarize with the hierarchy of coronary arteries and common sites of disease.

Recognize that enzyme elevation confirms myocardial necrosis.

Overview of Coronary Artery Disease

Crée tes propres fiches en 30 secondes

1. Overview

2. Core Concepts & Key Elements

3. High-Yield Facts

4. Summary Table

5. Mini-Schema (ASCII)

6. Rapid-Review Bullets

Overview of Coronary Artery Disease

Crée tes propres fiches en 30 secondes

Coronary Artery Disease (CAD) / Ischemic Heart Disease (IHD) Revision Sheet

1. 📌 Essentials

2. 🧩 Key Structures & Components

3. 🔬 Functions, Mechanisms & Relationships

4. Comparative Table for Angina and MI

5. 🗂️ Hierarchical Diagram

6. ⚠️ High-Yield Pitfalls & Confusions

7. ✅ Final Exam Checklist

Overview of Coronary Artery Disease

Overview of Coronary Artery Disease

What is the typical oxygen demand and supply for the myocardium at rest and during exercise?

Overview of Coronary Artery Disease

Progression globale

Détail par thème

Introduction au système

Les différents types

Structure axiale

Structure appendiculaire

Suivi de progression par thème