Atrial Fibrillation Flashcards
(30 cards)
What is the range for a normal heart rate?
60-100 bpm
What happens in atrial fibrillation?
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.
What is the physiological cause of AF?
Abnormal electrical impulses fire in the atria and override the SAN
Describe factors that increase the risk of AF.
Old age, hypertension, atherosclerosis, heart valve problems
Why would a blood test be useful when checking for AF?
You can check for cholesterol levels, which can indicate if an individual is likely to have atheromas which increase risk of having AF
Why would an ECG be useful to check for AF?
Can check heart rate and rhythm
What is amlodipine used for?
Used to treat hypertension
What is atrial fibrillation a significant risk factor for? Why is this?
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)
What is Warfarin used for?
An anticoagulant used to prevent blood clots
What type of drug is atenolol? What is it used for? How does it work?
. 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
What are the common side effects of amlodipine and atenolol?
Dizziness and tiredness
Why are aspirin and atenolol not often used together?
Aspirin can reduce the effects of atenolol
How is the liver involved in blood clotting?
Liver uses vitamin K to produce clotting factors that cause platelets and fibrin to form a clot
How does warfarin work?
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.
Why might someone with AF be prescribed warfarin?
To reduce the risk of blood clots forming because people with AF are at a higher risk of stroke
What is the INR?
. International Normalised Ratio
. Measures time taken for blood to clot
What does a higher INR show? How about a lower INR?
Higher INR shows blood takes longer to clot, lower shows blood clots more quickly
Why is it important to check the INR before prescribing someone anticoagulants?
To regulate the dose so that the blood isn’t dangerously thinned, which could cause excessive bleeding
What is the INR of a normal healthy person?
1
What is the targeted INR for a person with hypertension?
2-3
Why shouldn’t a patient take warfarin if they have recently had surgery or have a stomach ulcer?
Warfarin lowers the blood’s ability to clot, so can cause excessive internal bleeding
What is the ‘yellow book’?
Book given to patients who are prescribed warfarin to show them how to take it properly
Why is it bad to be taking warfarin and erythromycin together?
Erythromycin increases the anticoagulant effect of warfarin, which increases the risk of excessive internal bleeding
What is DC cardioversion used for?
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
