Atrial Fibrillation

Question 1

What is the range for a normal heart rate?

Answer 1

60-100 bpm

Question 2

What happens in atrial fibrillation?

Answer 2

The atria contract irregularly and sometimes too quickly, so the heart muscle can’t relax properly between contractions. This means that the heart misses pumping blood around the body for a beat and must compensate by making the next contraction more powerful to pump enough blood around the body.

Question 3

What is the physiological cause of AF?

Answer 3

Abnormal electrical impulses fire in the atria and override the SAN

Question 4

Describe factors that increase the risk of AF.

Answer 4

Old age, hypertension, atherosclerosis, heart valve problems

Question 5

Why would a blood test be useful when checking for AF?

Answer 5

You can check for cholesterol levels, which can indicate if an individual is likely to have atheromas which increase risk of having AF

Question 6

Why would an ECG be useful to check for AF?

Answer 6

Can check heart rate and rhythm

Question 7

What is amlodipine used for?

Answer 7

Used to treat hypertension

Question 8

What is atrial fibrillation a significant risk factor for? Why is this?

Answer 8

AF is a risk factor for stroke because blood clots are more likely to form in the brain
(Either due to the high pressure spurts of blood, which cause damage to blood vessel walls and thus lead to the formation of clots. Or, blood that’s not pumped out efficiently pools and forms a clot. These clots can then travel to vessels in the brain)

Question 9

What is Warfarin used for?

Answer 9

An anticoagulant used to prevent blood clots

Question 10

What type of drug is atenolol? What is it used for? How does it work?

Answer 10

. Beta-blocker used to lower BP
. Inhibits action of noradrenaline on B1-adrenoceptors on heart and blood vessels
. Decreases heart rate and dilates blood vessels

Question 11

What are the common side effects of amlodipine and atenolol?

Answer 11

Dizziness and tiredness

Question 12

Why are aspirin and atenolol not often used together?

Answer 12

Aspirin can reduce the effects of atenolol

Question 13

How is the liver involved in blood clotting?

Answer 13

Liver uses vitamin K to produce clotting factors that cause platelets and fibrin to form a clot

Question 14

How does warfarin work?

Answer 14

Warfarin is a vitamin K antagonist, which means that it stops the liver from being able to produce clotting factors using vitamin K. This inhibits the clotting cascade.

Question 15

Why might someone with AF be prescribed warfarin?

Answer 15

To reduce the risk of blood clots forming because people with AF are at a higher risk of stroke

Question 16

What is the INR?

Answer 16

. International Normalised Ratio

. Measures time taken for blood to clot

Question 17

What does a higher INR show? How about a lower INR?

Answer 17

Higher INR shows blood takes longer to clot, lower shows blood clots more quickly

Question 18

Why is it important to check the INR before prescribing someone anticoagulants?

Answer 18

To regulate the dose so that the blood isn’t dangerously thinned, which could cause excessive bleeding

Question 19

What is the INR of a normal healthy person?

Answer 19

1

Question 20

What is the targeted INR for a person with hypertension?

Answer 20

2-3

Question 21

Why shouldn’t a patient take warfarin if they have recently had surgery or have a stomach ulcer?

Answer 21

Warfarin lowers the blood’s ability to clot, so can cause excessive internal bleeding

Question 22

What is the ‘yellow book’?

Answer 22

Book given to patients who are prescribed warfarin to show them how to take it properly

Question 23

Why is it bad to be taking warfarin and erythromycin together?

Answer 23

Erythromycin increases the anticoagulant effect of warfarin, which increases the risk of excessive internal bleeding

Question 24

What is DC cardioversion used for?

Answer 24

Used to return heat back to sinus rhythm (regular heart rate set by SAN)
simultaneously, which interrupts abnormal heart rhythm
. This allows the SAN to resume normal pacemaker activity and reset the normal regular contraction of the atria then ventricles

Question 25

How does DC cardioversion work?

Answer 25

. Electrical shock applied during R waves or QRS complex of cardiac cycle
. Electrical currents travel across myocardium from negative to positive electrode, causing cardiomyocytes to contract simultaneously
. Allows SAN to resume normal heart contraction of atria then ventricels

Question 26

What risk are patient with long-standing AF put at when undergoing DC cardioversion?

Answer 26

At risk of thromboembolism (clot from other part of circulation lodges somewhere else)

Question 27

Why are patients with long-standing AF given anticoagulants before they undergo DC cardioversion?

Answer 27

To reduce the risk of thromboembolism occurring

Question 28

What is rivaroxaban used for? How does it work?

Answer 28

. Used to reduce blood clotting by inhibiting activated factor X
. Inhibits coagulation cascade, which reduces the risk of clotting and stroke

Question 29

Give two main advantages of taking rivaroxaban instead of warfarin.

Answer 29

No diet restrictions and don’t need regular blood tests to monitor INR because rivaroxaban has predictable effects

Question 30

Why should you not suddenly start changing the amount of green vegetables you consume when on warfarin?

Answer 30

Green vegetables contain lots of vitamin K, so suddenly eating lots/less of them can cause you vit K level to increase and affect your INR readings