Arrhythmias Flashcards
(41 cards)
What is the term for arrhythmias that are located above the ventricle, which origins of arrhythmia would be there?
Supraventricular arrhythmias (SA node, AV node, atria and His origin.
What is an ectopic beat?
It is a beat that has originated from somewhere other than the SA node.
What is triggered activity?
It is during phase 3 of cardiac myocytes where where there are afterdepolarizations that cause sustained depolarisations.
Factors that cause arrhythmias can lead to an increase in the slope of phase 4 in myocytes leading to an increased heart rate. This is caused by what?
Hyperthermia.
Hypercapnia.
Hypoxia.
Hyperkalemia.
What are some of the symptoms of arrhythmias?
Palpitations. SOB. Presyncope. Syncope. Heart failure. Sudden cardiac death. Angina.
What are some of the investigations you can do into arrhythmias?
ECG. Electrocardiography (ECHO). Exercise ECG. Holors 24hr ECG. CxR
Describe Sinus bradycardia?
HR <60 BPM
Regular rhythm.
Many athletes have.
Treat with atropine.
Describe sinus tachycardia?
HR >100 BPM
Treat underlying causes.
Maybe use beta blockers.
What are the three types of supraventricular tachycardia?
AV nodal reentrant tachycardia (AVNRT)
AV reciprocating tachycardia (AVRT).
Ectopic atrial tachycardia (EAT).
How do you treat an acute supraventricular tachycardia
You are trying to slow the HR and increase vagal tone. II adenosine (potent vasodilator). or verapamil (calcium channel antagonist) if adenosine not good enough.
How do you treat chronic supraventricular tachycardia
Antiarrhythmic drugs - digoxin.
B-blockers - bisoprolol.
RFCA - selective cutting of cardiac tissue to prevent tachycardia.
Describe 1st degree heart block?
It is not really heart block, the PR interval is just increased by >0.2 seconds, every P wave results in a QRS complex
Describe 2nd degree heart block - mobitz type 1?
It is intermittent block at the AV node, PR interval gets increasingly long to the point that a heart beat is missed, happens due to atrial impulses getting weaker and weaker to the point that they fail to stimulate ventricular contraction, cycle then repeats.
Describe 3rd degree heart block?
No action potentials from the SA node get to the AV node.
What are the four types of AF?
Permanent - not treatable.
Persistent - lasts for >48hrs.
Paroxysmal - lasts <48 hrs.
Lone (idiopathic) AF - no identifiable cause.
What rate controlling drugs should you use for AF?
Digoxin.
Verapamil - calcium channel antagonist.
B-blockers.
What rhythm controlling methods should you use for AF?
Amiodarone (anti-arrhythmic drugs).
Direct current cardioversion - shocking the patient.
What would appear in the ECG of AF?
no p-waves.
Rapid QRS rhythm (>200 BPM).
HR irregularly irregular.
What is atrial flutter?
It is caused by a re-entrant rhythm in either atrium.
There is a self-perpetuating loop due to an extra electrical pathway in the atrium.
Leads to very high HR.
How would atrial flutter appear on an ECG?
Saw tooth appearance.
What causes a supraventricular tachycardia?
The electrical signal re-enters the atrium, it then goes back through the AV node. This causes another ventricular contraction meaning that the HR is very fast.
What would the QRS complex look like in a supraventricular tachycardia and the overall ECG?
It would be very narrow and last less than 0.12 seconds.
T wave, then immediately QRS complex then immediately T wave and so on.
What will/won’t appear on an ECG in AF and why?
P waves won’t because atrial fibrillation is due to disorganised atrial electrical activity
Very narrow QRS complexes due to short contractions
An irregularly irregular rhythm.
As there are irregular conductions in AF what happens to the ventricular contractions and what possible condition may occur as a side effect?
They become irregular irregular.
Tachycardic.
Heart failure due to poor filling of the ventricles.
