2. Ischemic heart disease

Types of ischemic heart disease

1. Stable/chronic/typical angina Pectoris

2. Acute coronary artery syndrome which includes

   Unstable angina

   Myocardial infarction

   Variant (prinzmetals angina)

   Silent ischemia

   Microvascular angina

   Sudden cardiac death

Stable angina

Predictable chest pain triggered by excretion or stress, relieved by rest or nitroglycerin

Underlying cause of stable angina

Stable atherosclerotic plague

Mechanism of stable angina

Fixed, partial obstruction of coronary arteries leading to decreased blood flow during increased oxygen demand

Common signs of stable angina

Substernal chest pain (pressure, heaviness)

Radiates top left arm or jaw

Triggered by excretion or emotion

Relieved within minutes by rest or nitrates

When do signs of stable angina occur

During physical or emotional stress

Diagnosis of stable angina

Normal ECG at rest, stress ECG may show ST depression

Relieved by nitrates and rest

Negative troponins

Coronary angiography shows fixed stenosis

Duration of pain of stable angina

Less than 15 minutes that is to say 2-5 miners per episode

Acute coronary syndrome

Includes

Unstable angina Pectoris,

Myocardial infarction which is classified into STEMI (ST elevation MI) and NSTEMI (Non ST elevation MI)

Myocardial infarction

is the irreversible death of heart muscle tissue due to prolonged blockage of blood flow in a coronary artery for a long time, leading to ischemia and necrosis.

STEMI(ST elevation Ml)

Is the acute necrosis of myocardium with ST elevation on ECG

Underlying cause of STEMI

Plague rupture with complete thrombotic occlusion

Mechanism of STEMI

Complete coronary artery occlusion

Common signs of STEMI

Severe, crushing chest pain >30 minutes

Diaphoresis, dyspnea, nausea, palpitations

Signs of cardiogenic shock in severe cases

When signs of STEMI occur

Often at rest, early morning; sudden onset

Diagnosis of STEMI

ECG: ST-segment elevation in ≥2 contiguous leads.

Troponins: Elevated.

Coronary angiography: Complete vessel occlusion.

Duration of chest pain in STEMI

Greater than 30 minutes

NSTEMI (Non ST elevation MI)

Subendocardial myocardial infarction without ST elevation

Underlying cause of NSTEMI

Plague rupture with partial thrombotic occlusion

Mechanism of NSTEMI

Subendocardial ischemia due to reduced blood flow

Common signs of NSTEMI

Similar chest pain as STEMI

Less intense or prolonged than STEMI

Symptoms may be intermittent

When signs occur in NSTEMI

Often at rest, not always associated with exertion

Diagnosis of NSTEMI

ECG: ST depression, T-wave inversion; no ST elevation.

Troponins: Elevated.

Angiography: Partial occlusion.

Duration of pain in NSTEMI

Greater than 20 minutes

Variant angina

Episodic chest pain at rest due to coronary artery spasm

Underlying cause of variant angina

Vasospasm of coronary arteries, often with no fixed obstruction

Mechanism of variant angina

Transient coronary artery spasm, leading to ischemia

Common signs of variant angina

Chest pain at rest, often in early morning

May be severe and recurrent

When signs of variant angina occur

Usually at rest, especially at night/early morning

Diagnosis of variant angina

ECG during episode: Transient ST elevation.

Troponins: Normal unless prolonged.

Provocation testing or angiography with ergonovine.

Duration of pain of variant angina

Usually 5-30 minutes

Silent ischemia

Myocardial ischemia without subjective symptoms

Underlying cause of silent ischemia

Stable or unstable atherosclerosis; often seen in diabetics

Common signs of silent ischemia

Often asymptomatic

May present when signs of heart failure or arrhythmia

Women signs of silent angina occur

Often detected accidentally

Diagnosis of silent angina

Abnormal stress ECG or Holter monitoring

Positive myocardial perfusion scan

Microvascular angina

Angina with normal coronary arteries on angiography

Underlying cause of Microvascular angina

Dysfunction of small coronary vessels

Mechanism of Microvascular angina

Impaired microcirculatory vasodilation, leading to ischemia

Common signs of Microvascular angina

Typical angina-like chest pain

Often more prolonged, not always exertion-related

Diagnosis of Microvascular angina

ECG: May show ischemic changes during stress.

Angiography: Normal epicardial coronary arteries.

Duration of pain in Microvascular angina

Greater than 10 minutes

Sudden cardiac death (SCD)

Unexpected cardiac death within 1 hour of symptom onset

Underlying cause of sudden cardiac death

Ischemia induced ventricular arrhythmias e.g VF , VY

Common signs of sudden cardiac death

Sudden collapse, no pulse or respiration

Often preceded by chest pain or palpitations

When signs occur

Often early post infarction or as first presentation of lHD

Diagnosis of sudden cardiac death

Clinical (witnessed arrest)

ECG: May show VT/VF

Autopsy shows acute infarction or arrhythmias substrate

Duration of sudden cardiac death

Immediate, fatal within minutes without resuscitation

Risk factors of ischemia heart disease

Non-Modifiable

• Age (men >45 years, women >55 years)

• Male sex

• Family history of premature CAD

• Genetic predisposition

Modifiable

• Hypertension

• Diabetes mellitus

• Dyslipidemia (high LDL, low HDL)

• Smoking

• Obesity

• Physical inactivity

• Unhealthy diet

• Chronic stress

• Excessive alcohol consumption

Major cause of ischemic heart disease

Deposition of fatty material (cholesterol plagues) and platelet aggregation inside the coronary arteries of the heart, thus leading to ischemia and or infarction

Pathophysiology of ischemic heart disease

Ischemic heart disease occurs when there is an imbalance between myocardial oxygen supply and oxygen demand, most commonly due to reduced coronary blood flow.

1. Initial event: Coronary artery narrowing

The most common cause is coronary atherosclerosis, where plaques form inside coronary arteries.

Atherosclerosis process:

Endothelial injury (from smoking, hypertension, diabetes, dyslipidemia)

LDL cholesterol enters vessel wall

Oxidation of LDL → triggers inflammation

Monocytes → macrophages → foam cells

Fatty streak → fibrous plaque

Plaque grows and narrows lumen

👉 Result: reduced coronary blood flow (chronic ischemia)

2. Reduced oxygen supply to myocardium

Due to:

Fixed stenosis (atherosclerotic plaque)

Acute plaque rupture → thrombus formation

Coronary vasospasm (e.g., Prinzmetal angina)

Reduced oxygen carrying capacity (anemia, hypoxia)

3. Increased myocardial oxygen demand

Demand increases with:

Exercise

Emotional stress (sympathetic stimulation)

Tachycardia

Hypertension (↑ afterload)

Left ventricular hypertrophy

4. Myocardial ischemia (core problem)

When supply < demand:

Cellular changes:

↓ ATP production (anaerobic metabolism starts)

Lactic acid accumulation → pain (angina)

Na⁺/K⁺ pump failure → cellular swelling

Calcium overload → contractile dysfunction

Reduced myocardial relaxation and contraction

5. Clinical consequences

Depending on severity and duration:

(a) Reversible ischemia

Stable angina

No permanent cell death

(b) Prolonged ischemia

Unstable angina

Severe plaque rupture + partial thrombosis

(c) Complete occlusion

Myocardial infarction (MI)

Irreversible myocardial necrosis

6. Reperfusion injury (after blood flow returns)

Even after restoration:

Free radical generation

Calcium overload worsens

Inflammatory damage increases

Summary flow

Endothelial injury → atherosclerosis → coronary narrowing → ↓ blood flow → ischemia → ATP depletion + lactate buildup → angina or infarction

Causes of ischemic heart disease

Atherosclerosis

• Coronary artery spasm (e.g., Prinzmetal angina)

• Embolism to coronary arteries

• Coronary artery dissection

• Coronary artery anomalies

• Vasculitis (e.g., Kawasaki disease)

• Severe anemia

• Hypertrophic cardiomyopathy

• Aortic stenosis

• Tachyarrhythmias

• Cocaine or amphetamine use

• Diabetes mellitus

• Hypertension

• Hyperlipidemia

• Hyperhomocysteinemia

• Obesity

• Smoking

• Sedentary lifestyle

• Post-radiation therapy

• Autoimmune diseases (e.g., lupus)

Signs and symptoms of ischemic heart disease

• Chest pain (angina)

• Radiating pain (left arm, neck, jaw)

• Dyspnea (shortness of breath)

• Fatigue

• Nausea

• Vomiting

• Sweating (diaphoresis)

• Palpitations

• Syncope or dizziness

• Tachycardia

• Bradycardia

• Cyanosis

• Anxiety or sense of impending doom

• Orthopnea

• Paroxysmal nocturnal dyspnea

• Hypotension (in MI)

• Pulmonary edema

• Heart murmurs

• Cold, clammy skin

• Reduced exercise tolerance

Differential diagnosis of ischemic heart disease

Gastroesophageal reflux disease (GERD)

• Esophageal spasm

• Musculoskeletal chest pain

• Pericarditis

• Aortic dissection

• Pulmonary embolism

• Pneumothorax

• Mitral valve prolapse

• Anxiety disorders

• Costochondritis

Diagnosis of ischemic heart disease

1. Stable Angina (CCS Classification)

• Class I: Angina with strenuous exertion

• Class II: Angina with moderate exertion (e.g., walking >2 blocks)

• Class III: Angina with mild exertion (e.g., walking <2 blocks)

• Class IV: Angina at rest or with minimal exertion

2. Unstable Angina

• Rest angina >20 min

• New-onset angina (<2 months)

• Increasing angina (frequency, severity, duration)

3. Myocardial Infarction (MI)

• STEMI: ST-elevation on ECG + troponin elevation

• NSTEMI: Normal or ST-depression + troponin elevation

Diagnosis of ischemic heart disease from UCG

Cardiac enzymes(CPK, troponin)

ECG (at rest and stress ECG)

Echocardiogram

Goals of management of ischemic heart disease

Stable Angina

• Relieve symptoms

• Reduce myocardial oxygen demand

• Prevent progression to MI or acute coronary syndrome

• Prevent further growth of plaques

• Improve quality of life

• Control risk factors (BP, lipids, diabetes)

Unstable Angina/NSTEMI

• Prevent MI and death

• Relieve ischemia

• Stabilize plaques

• Reduce clot formation

STEMI

• Revascularization (PCI or thrombolysis)

• Salvage myocardium

• Prevent complications (arrhythmias, failure)

Silent Ischemia

• Detect via monitoring

• Prevent progression with anti-ischemic therapy

 

Non pharmacological management of ischemic heart disease

Smoking cessation

• Low-fat, low-sodium diet

• Regular aerobic exercise

• Weight loss

• Stress reduction

• Control of diabetes and hypertension

• Limit alcohol

Non pharmacological management of stable angina

Avoid known triggers (cold, exertion, stress)

• Lifestyle optimization

• Cardiac rehab programs

Non pharmacological management of post myocardial infarction or unstable angina

Early mobilization

Structured cardiac rehabilitation

Implantable defibrillator in high-risk patients

Long-term lifestyle adherence