Ischaemic Heart Disease And Angina

Question 1

What is the most common cause of stable ischaemic heart disease and low risk unstable angina?

Answer 1

Atheromatous plaques in the coronary arteries which disrupt blood flow

Question 2

What is angina pectoris?

Answer 2

A typical symptom of ischaemic heart disease resulting from an imbalance between myocardial oxygen supply and demand

Question 3

What is the nature of anginal pain? (Use SOCRATES)

Answer 3

It is usually a substernal, chest discomfort, described as a pressure or heaviness that is provoked by exercise and relieved by rest or glyceryl nitrate
The pain is sometimes referred and in this case is experienced in the left neck, jaw, epigastric or arm
It typically lasts for several minutes

Question 4

What are the associated factors of angina?

Answer 4

Dyspnoea on exertion
Nausea and vomiting
Perspiration
Fatigue
Hypoxia
Tachycardia

Question 5

What is stable angina?

Answer 5

Stable angina has the most predictable attacks i.e. it is exacerbated by exercise and stress and is the result of an unmet myocardial oxygen demand

Question 6

What is unstable angina?

Answer 6

This has unpredictable attacks and a coronary artery occlusion component due to platelet adhesion to the ruptured atherosclerotic plaque

Question 7

What is variant angina?

Answer 7

This results in unpredictable attacks where coronary artery occlusion occurs through vasospasm

Question 8

Why is coronary artery dilation dangerous in stable and unstable angina?

Answer 8

It may cause coronary steal

Question 9

Explain the concept of coronary steal

Answer 9

More blood is sent to an already well perfused area which is capable of dilation but in the areas where dilation cannot occur less blood is delivered because of the fall in input pressure

Question 10

What are the risk factors for ischaemic heart disease?

Answer 10

Advancing age
Smoking
Hypertension
Isolated low HDL cholesterol
Elevated LDL cholesterol
Diabetes
Inactivity
Obesity
Family history of the disease
Illicit drug use
Male sex

Question 11

Internal organs are insensitive to touch, cutting and temperature. What factors, instead, cause pain in visceral organs?

Answer 11

Stretching or chemical changes such as ischaemia

Question 12

How does the phenomenon of referred pain occur?

Answer 12

The pathways of the visceral organ sensory nerves and somatic sensory nerves converge at the same level of the spinal cord and the signal is then transmitted from here to the brain. Somatic pain is more common than visceral pain, so the brain can confuse the signals resulting in pain from the visceral organs being experienced elsewhere i.e. the skin

Question 13

Visceral pain is usually sharp and localised whereas somatic pain is dull and poorly localised. T/F?

Answer 13

False the opposite is true

Question 14

What is the purpose of the initial laboratory tests of haemoglobin, blood glucose and lipid panels when investigating angina?

Answer 14

Haemoglobin is to test for anaemia as this could be a contributing factor for the angina or could be an alternative cause of pain
Lipid panels and blood glucose are used to investigate metabolic abnormalities associated with the risk factors diabetes and hypercholesterolaemia

Question 15

What is the first investigatory test for angina?

Answer 15

Resting ECG

Question 16

What protocol is used in an exercise stress ECG?

Answer 16

Bruce protocol

Question 17

What is the bruce protocol?

Answer 17

A test where the intensity of exercise on a treadmill is gradually increased, the pace and incline are increased every 3 mins up til 21 mins with the heart being monitored on an ECG throughout

Question 18

What results from an exercise stress ECG could indicate ischaemic heart disease?

Answer 18

ST depression of greater than 2mm
ST segment elevation
Failure to increase systolic blood pressure
Sustained decreased in bp after an appropriate rise during exercise
Low exercise tolerance

Question 19

What tests other than an exercise stress ECG could be done on a patient when investigating angina and in what circumstances would these tests be performed?

Answer 19

Stress myocardial perfusion imaging
Stress echocardiography

These are done when there are abnormalities in the resting ECG than indicate that an exercise stress ECG should not be performed

Question 20

What lifestyle factors should be modified to manage ischaemic heart disease?

Answer 20

Encouraging 30-60 mins of moderate intensity aerobic activity at least 5 days per week
Smoking cessation
Weight management
Elimination of stress

Question 21

How do beta one adrenoceptor blockers work to manage ischaemic heart disease?

Answer 21

The decrease the activity of noradrenaline and adrenalin on the heart to decrease the heart rate which decreases myocardial oxygen demand

Question 22

How does ivabradine work to manage ischaemic heart disease?

Answer 22

It blocks the sodium current that contributes to SA node depolarisation towards threshold and decreases heart rate but not force which decreases metabolic oxygen demand

Question 23

What drug is commonly used for prophylaxis in stable angina?

Answer 23

Nitrovasodilators

Question 24

What other nitrovasodilators exist other than nitroglycerine?

Answer 24

Isosorbide dinitrate

Isosorbide mononitrate

Question 25

How do nitrovasodilators work to manage ischaemic heart disease?

Answer 25

They readily enter smooth muscle cells where they are reduced to nitric oxide which acts on the blood vessel to induce vasodilation by binding to the haem group of the guanylate cyclase receptor to convert GTP to cGMP

Question 26

What are the side effects of nitrovasodilators?

Answer 26

Headaches

Tolerance with prolonged use

Question 27

Vasodilators have a more potent effect on venous dilation than arterial dilation. T/F?

Answer 27

True

Question 28

In what type of angina is dilatation of the coronary arteries by calcium channel blockers useful?

Answer 28

Variant angina

Question 29

What is the first line treatment for ischaemic heart disease?

Answer 29

Short acting nitrovasodilator with a beta blocker or calcium channel blocker and drugs for secondary prevention (drugs which act to combat risk factors of the disease e.g. lipid lowering or anti hypertensive drugs)