Arrhythmias Flashcards
Ecchymosis
bruise, discoloured spot resulting from an accumulation of blood under the skin surface caused by an injury
Ablation
- when they try to calm the rhythm of the heart by burning of some nerve fibres inside the heart
- they gain access to the heart by going through lungs and gaining access to pulmonary vessels
Heart Arrhythmia
abnormal heart rhythm
Three types of arrhythmias
bradycardia, tachycardia, and uncoordinated contractions
Bradycardia
- slower than normal heart rate and is usually less than 60 bpm
Tachycardia
- faster than normal heart rate and is usually more than 100 bpm
Uncoordinated contractions
causes fibrilation
list the two syndromes that can cause bradycardia
carotid sinus syndrome, and heart block
How does carotid sinus syndrome cause bradycardia?
baroreceptors on the carotid artery are excessively sensitive which triggers a response from the vagus nerve, causing a domination of the vagal-Ach effects on the heart which then causes a decrease in heart rate (i.e. bradycardia)
What are the two types of heart blocks that can lead to bradycardia?
SA block and AV block
How can SA block lead to bradycardia?
- SA block is when impulses from the SA node to atrial muscle are blocked and so atrial contraction does not occur
- atrial contraction is depolarization which means there is an ending of the P wave
How did AV block lead to bradycardia?
- AV block is when impulses through the Bundle of His is blocked which slows down impulse travel from atria to ventricle
Where is electrical activity initiated in the heart?
SA node
How do contractions start?
Electrical activity initiated at SA node is sent to the AV node which then makes its way to the Bundle of His which then sends it to the Purkinje fibres to cause coordinated contraction.
Bachman’s bundle
responsible for coordinating the contraction of both the left and right atria, and the left and right ventricle
What are the three key stages of the cardiac cycle?
P, QRS complex and T.