Arrythmias Flashcards
Where do supraventricular arrythmias originate?
Above the ventricle, e.g.: SA node, Atrial muscle, AV Node, the origin of the bundle of His.
What does the Bachmann’s bundle supply?
Supplies electrical activity to the left atrium.
What are ectopic beats?
Heart beats that originate outside the SA node
Name as many supraventricular arrythmias as you can.
TACHY Atrial fibrillation Atrial flutter Ectopic atrial tachycardia BRADY Sinus bradycardia Sinus pauses
Name as many AV node arrythmias as you can.
AVN re-entyr
Accessory pathways - Wolff-Parkinson White
AV block - 1,2+3
Name as many ventricular arrythmias as you can.
Premature ventricular complex (PVC)
Ventricular Tachycardia
Ventricular Fibrillation
Asystole
What can cause arrythmias?
Congenital defects of the heart Sympathetic stimulation and increased vagal tone Hypoxia Ischaemia Electrolyte imbalance Inflammation Drugs Genetics
What is the basic cause of arrythmias?
A change in automaticity.
Does hypothermia cause bradycardia or tachycardia?
Bradycardia
It decrease the phase 4 slope
Does hyperthermia cause bradycardia or tachycardia?
Tachycardia
It increases the phase 4 slope
Does hypercapnia cause bradycardia or tachycardia?
Tachycardia
It increases the phase 4 slope
Does hypoxia cause bradycardia or tachycardia?
Tachycardia
It increases the phase 4 slope
Does cardiac dilation cause bradycardia or tachycardia?`
Tachycardia
It increases the phase 4 slope
Does hypokalaemia cause bradycardia or tachycardia?
Tachycardia
It increases the phase 4 slope
Also increases the presence of ectopics and prolongs repolarisation.
Does hyperkalaemia cause bradycardia or tachycardia?
Bradycardia
It decrease the phase 4 slope
It slows conduction and blocks
What does Digoxin toxicity cause?
Palpitations and irregular pulse. (Small depolarisation after phase 3)
What are the symptoms of ischaemia and re-entry arrythmia?
Palpitations Dizziness Dyspnoea Syncope Sudden cardiac death Worsening of current conditions
Name the investigation for structural heart disease
Echocardiogram
Name the investigation to assess rhythm, signs of previous MI and pre-excitation
ECG
Name the investigation to assess ischaemia and exercise induced arrythmias.
Exercise ECG
Name the investigation to assess for paroxysmal arrythmias
24hr Holter ECG
What kind of symptoms would you see in atrial ectopic beats
Often none or palpitations
How would you treat Atrial ectopic beats?
Generally no treatment
Avoids stimulants like caffeine and cigarettes
B blockers can help
How would you treat bradycardia?
Atropine
What is sinus bradycardia?
Heart rate
What is sinus tachycardia?
Heart rate >100bpm
How would you treat tachycardia?
Treat underlying pathology
B blockers
What is the treatment for SVT (Supraventricular tachycardia)
Vagal manoeuvres e.g carotid massage
IV Adenosine -A1 blocker
IV Verapamil - Calcium Channel Blocker
What is the chronic treatment for SVT?
Avoid stimulants
B blockers &/or Calcium channel blocker
What is ablation?
Selective cautery of cardiac tissue to prevent tachycardia, targeting either an automatic focus or part of a re-entry circuit.
Describe 1st degree heart block
Longer PR interval than normal (>0.2 sec)
No treatment
But long term follow up as it could get worse
What is Mobitz I heart block?
2nd degree heart block
Causes progressive lengthening of PR interval resulting in a dropped beat
Usually vagal in origin
What is Mobitz II heart block?
2nd degree heart block Pathological May progress to complete heart block Its normally 2 beats to 1 dropped beat e.g 2:1 or can be 3:1 Permanent pacemaker needed
Describe 3rd degree heart block
No action potential from the SAN get to through the AVN
Random P waves with no association to QRS
List the options for acute pacing
Transcutaneous - Emergency until venous access is achieved.
Tranvenous pacer - Via main vein.
What are the two types of pacemakers?
Single chamber - Used for arrythmias involving SAN
Dual chamber - Used for AVN disease
How would you treat Premature ventricular ectopics?
B-Blockers
If they are worse on exercise you need to investigate further.
What is a ventricular tachycardia caused by?
Life threatining condition caused by Coronary artery disease Previous MI Cardiomyopathy Inherited arrythmias
What is ventricular fibrillation?
Chaotic ventricular electrical activity
Heart loses its ability as a pump`
What is the treatment for VF?
Defib and resuscitation.
What is the treatment for VT?
DC Cardioversion in acute unstable cases
If stable consider pharmacological cardioversion
What is the long term treatment for VT?
Correct ischaemia
ICD (Implantable cardioverter defibrillator)
Optimise CHF therapies
What can cause Torsades de Pointes
Digitalis toxicity
