Atrial Fibrillation Flashcards
Which anatomical structures are affected in atrial fibrillation?
The right and left atria
The pulmonary veins where they meet the left atrium
What physiology is affected in atrial fibrillation?
The pacemaker activity of the heart
How does atrial fibrillation affect the ventricles?
The conduction of electrical depolarisation through the atrium is affected
This affects stimulation of electrical activity in the ventricles
What structural abnormalities are present in atrial fibrillation?
The atria are dilated
There is fibrosis (scarring) of the atrial muscle
How is pacemaker activity of the heart affected in atrial fibrillation?
The SA node is overwhelmed by disorganised electrical discharge
Where does the disorganised electrical activity usually originate from?
at a pulmonary vein insertion
What 6 prior events may lead to atrial fibrillation?
- hypertension
- primary heart diseases
- lung diseases
- excessive alcohol consumption
- hyperthyroidism
- heart failure
What symptoms are experienced by the patient?
- palpitations
- tired and/or breathless with exercise
- sometimes chest tightness (angina)
- sometimes ankle swelling (oedema)
What is meant by heart palpitations?
This is awareness of the heart beat
It may be fast, irregular or both
What clinical signs may be seen in a patient with atrial fibrillation?
- irregular pulse
2. signs of an underlying cause
What signs of an underlying cause may be seen?
- high blood pressure
- lung disease
- valve murmur heard with stethoscope
- weight loss with overactive thyroid
What abnormal test results may be seen in a patient with AF?
ECG - there are no clear P waves
What 3 methods of medical/surgical intervention are used to treat AF?
- rate control
- rhythm control
- electrically isolating the pulmonary veins from the elft atrium
Which drugs are used to control the heart rate?
digoxin, beta-blockers, verapamil
What is the aim of treatment through rate control?
This seeks to slow down the heart rate to prevent palpitations and to improve the efficiency of the heart beat
Which drugs/other treatments are used to control the heart rhythm?
drugs - amiodarone
DC (direct current) cardioversion is electrical shock treatment
What is the aim of treatment for AF through rhythm control?
This seeks to convert the heart rhythm back to normal, regular sinus rhythm
How can the pulmonary veins be electrically isolated from the left atrium?
- surgery
- catheter - placing a tube in the heart from the arm/leg
- ablation
What is ablation?
Use of an energy pulse which makes the atrial cells unable to conduct electricity
How can patients work to try and prevent AF?
Avoid consuming an excess of alcohol and stimulants such as nicotine and caffeine
What is the most effective way of preventing AF?
Early and effective treatment of diseases that causes atrial fibrillation
e.g. high blood pressure, lung diseases
Why is warfarin used in AF patients?
It prevents the formation of blood clots in the atrium
What is the downside of using aspirin occasionally as an alternative to warfarin?
It is less effective in preventing blood clot formation and embolisation
What is embolisation?
Movement of a blood clot from the atrium to the body
What happens if an embolus forms in the brain?
This causes a stroke due to death of brain tissue
What happens if an embolus forms in the leg or bowel?
Ischaemia due to lack of blood
or
Necrosis due to death of tissue
