Week 5: Angina

Atherosclerosis

Buildup of plaque in arteries, leading to reduced blood flow.

Coronary Artery Disease (CAD)

Narrowing or blockage of coronary arteries.

Ischemic Heart Disease

Reduced blood supply to the heart muscle.

Angina

Definition: Temporary ischemia, no tissue death.

Cause: Reduced blood flow, often due to atherosclerosis.

Pain: Chest discomfort, often predictable (e.g., with exertion).

Duration: Short-lasting (minutes), relieved by rest or nitroglycerin

Myocardial Infarction

Definition: Prolonged ischemia causing infarction and tissue necrosis.

Cause: Complete blockage of coronary artery (thrombus or rupture).

Pain: Severe, crushing, or burning, often radiating to arm, neck, or jaw.

Duration: Prolonged (20+ minutes), not relieved by rest or nitroglycerin.

The influence of Gender and Ethnicity on Angina

• Angina occurs more frequently in females

• Among racial-ethnic groups, the incidence of angina is highest amount Indigenous peoples and people of African descent

• Females of African descent have a risk of angina that is twice that of their male counterpart

Goals of Therapy Angina

• Minimize the frequency of attacks

• Decrease the duration and intensity of attacks

• Improve patient’s functional capacity

• Prevent or delay worse outcome (ie MI)

Drug Therapy for Angina

Therapy aims to increase blood flow to the ischemic myocardium and decrease myocardial oxygen demand

How Can We Decrease Myocardial Oxygen (O₂) Demand?

Decrease heart rate (HR): A slower heart rate means the heart requires less oxygen.

Decrease contractility: Reducing the force of heart contractions lowers oxygen demand.

Decrease blood pressure (BP): Reduces the workload on the heart.

Decrease preload: Reduces the amount of blood returning to the heart, lowering cardiac workload.

Decrease afterload: Reduces the resistance the heart must pump against.

Drugs for Angina (Stable Angina)

First line: Fast-acting nitrates

Drugs for Angina (Frequent, severe episodes)

Prophylactic treatment with transdermal nitrates, ß-Blockers (previously covered), and/or calcium channel blockers (previously covered)

Drugs for Angina Nitrates

• Mainstay for both prophylaxis and treatment for angina

• Given during anginal attack

• Multiple forms

• Rapid-acting and long-acting

Available forms of Nitrate

• Sublingual tablet *

• Translingual sprays*

• Intravenous solutions*

• Transdermal patches*

• Chewable tablets

• Ointments

• Oral capsules/tablets

*Bypass the liver and the first-pass effect.

Nitroglycerin: Mechanism of Action

Primary Action: Cause vasodilation by relaxing smooth muscles.

Effects:

• Venous Vasodilation: Reduces preload (decreases the volume of blood returning to the heart).

• Coronary Artery Dilation: Improves blood flow to ischemic areas.

Result:

• Reduces the heart's workload. Increases oxygen delivery to ischemic myocardial tissue.

Adverse Effects Nitroglycerin

• Headaches

• Dizziness

• Postural hypotension

• Reflex tachycardia

Tolerance may develop.

• Occurs in patients taking nitrates around the clock or with long-acting forms

• Prevented by allowing a regular nitrate-free period to allow enzyme pathways to replenish

• Transdermal forms: may be instructed to remove patch at bedtime for 8 hours, then apply a new patch in the morning

Contraindications of Nitroglycerin

• Severe anemia

• Hypotension

• Use of the erectile dysfunction drugs

• Severe head injury

• Closed-angle glaucoma

Nitro Patient Education: Application Activity

Patient Education is very important with Nitro use, topics may include:

• When to take it

• How to take it

• How to store it with rationale

• What symptoms to monitor for after dose

• When to call 911

ß-Blocker use for Angina

atenolol, metoprolol, propranolol, hydrochloride

• Block β1-receptors on the heart

Decrease heart rate, resulting in decreased myocardial oxygen demand and increased oxygen delivery to the heart

Decrease myocardial contractility, helping to conserve energy or decrease demand

Calcium Channel Blockers use with Angina

• Cause coronary artery vasodilation

• Cause peripheral arterial vasodilation, thus decreasing systemic vascular resistance

• Reduce the workload of the hear

Result: decreased myocardial oxygen demand

Dihydropyridine

Amlodipine, Nifedipine

Relax blood vessels → ↓ BP

Non-Dihydropyridine

Diltiazem, Verapamil

↓ Heart rate, ↓ contractility, ↓ BP

A patient with stable angina who was walking a dog developed chest pain and sat down. The patient continues to experience chest pain when sitting down. When should the patient call 911?

If one sublingual tablet does not relieve the pain after 5 minutes

A person who is mowing the lawn on a hot Saturday afternoon begins to notice chest pain. What should this person’s first action be?

Stop mowing and sit or lie down.