Arrhythmia 1 Flashcards
What does supraventricular mean and include?
Non-specific term as it means origin is above the ventricle
ie. AV node, SA node, atrial muscle. Slide 4
What are the possible supraventricular arrhythmias?
Atrial Fibrillation Atrial Flutter Ectopic Atrial Tachycardia Sinus bradycardia Sinus pauses. Slide 5
What are the possible ventricular arrhythmias?
Ventricular ectopics or premature ventricular complexes (PVC) Ventricular tachycardia Ventricular Fibrillation Asystole. Slide 6
What are possible arrhythmias that could arise in the AV node?
AVN re-entry tachycardia
AV reciprocating tachycardia
AV block from 1st to 3rd degree. Slide 7
What are the anatomical and autonomic nervous system causes for arrhythmias?
Anatomy:
LV hypertrophy
Accessory pathways
Congenital HD
Nervous:
Sympathetic stimulation e.g. stress
Increased vagal tone. Slide 9
Apart from anatomical and nervous causes, what else could cause arrhythmias?
Metabolic e.g. hypoxia Inflammation e.g. myocarditis Drugs Genetics e.g long QT syndrome Slide 9
What are the electrophysiological mechanisms of an arrhythmia?
Ectopic beats:
Altered automaticity
Triggered Activity
Re-entry:
Accessory pathway tachycardia.
Slide 10
What are the 4 ways to alter automaticity?
Change the slope to threshold
Change the threshold itself
Change resting memebrane potential
PNS can afftect phase 4 slope. Slide 13
Why does hypokalaemia cause an increase in heart rate?
Due to the increase in phase 4 slope and prolongs repolarisation. Slide 14
What is triggered activity and what are the potential causes?
In phase 3 a small depolarisation may occur whcih if sufficient then may triger a sustained train of depolarisations which is triggered activity.
Digoxin toxicity
Long QT syndrome and hypokalaemia
Slide 15
How does Re-entry of a potential cause an arrhythmia and what are some structural causes of re-entry?
There is a second conduction pathway and causes another potential to split off from the main potential and become a recurrent potential circling back to the atrium.
Structural: Accessory pathways, scars from previous MI and congenital HD. Slide 17+21
What are the symptoms of an arrhythmia?
Palpitations SOB Dizziness Syncope Faintness Sudden cardiac death Angina
What are the investigations of arrhythmias?
12 lead ECG CXR Echocardiogram Stress ECG for exercise related arrhythmias 24hr ECG Slide 26
On an ECG what indicates pre-excitation?
The slope up to the QRS called a delta wave and a short PR interval. Slide 28+44
Sinus arrhythmia is bad. True or False?
False, sinus arrhythmia is the only normal arrythmia where during inspiration and expiration the heart can speed up or slow down. Slide 35
What is the treatment for sinus bradycardia?
Atropine
Slide 36
What does orthodromic and antidromic AV reciprocating tachycardia present as on a ECG?
Orthodomic AVRT:
Inverted P wave after QRS
Antidromic AVRT:
Wide QRS complex with delta wave. Slide 44
What is the acute and chronic management of supraventricular tachycardia management?
Acute: Slow AV node conduction -IV adenosine/verapamil Increase vagal tone: -Carotid massage
Chronic: Avoid stimulants Radiofrequency ablation in young patients B blockers Anti-arrhythmic drugs. Slide 46
What is radiofrequency catheter ablation?
Selective cautery of cardiac tissue to prevent tachycaria. Slide 47
What are possible causes of heart block?
Ageing Acute MI Myocarditis Amyloid Drugs e.g. B blockers, Ca antagonists Aortic valve disease Genetic e.g. Lenegre's disease. Slide 51
What is 1st degree AV block and what is the treatment?
When the conduction from P wave to QRS is longer.
There is no treatment just monitor incase it gets worse. Slide 52
What are the two types of 2nd degree AV block?
Mobitz I: progressive lengthening of the PR interval and results in a dropped beat.
Mobitz II: Pathological and is usually in a 2:1 P wave to QRS.
Slide 53
What is 3rd degree heart block?
When there is no action potential from the SA node.
Instead there is only rhythm coming spontaneously from the ventricular myocytes. Slide 57
If the QRS complex is narrow it is ____, if the QRS complex is broad it is ____.
Atrial - narrow
Ventricular - broad
Slide 57
What are the types of pacemakers?
Single chamber or dual chamber. Slide 59
What are the possible causes for ventricular ectopic beats?
Structural: LVH, myocarditis
Metabolic: Ischaemic heart disease
Slide 61
If there is a man who is acute SOB at rest and chest pain
70 male, hypertension, diabetes, Smoker.
Had a remote MI six months ago.
What is the most common diagnosis?
Ventricular tachycardia until proven otherwise. Slide 63
What is ventricular tachycardia?
When patients have significant heart disease and is life threatening but is harmodynamically stable. Slide 64
Why do some patients feel light headed or syncope due to ventricular tachycardia?
As there is a large sustained reduction of arterial pressure. Slide 65
What are the differences between monomorphic VT and polymorphic and what does polymorphic VT have monomorphic doesn’t?
Monomorphic is haemodynamically stable as the VT rhythm is regular
Polymorphic is haemodynamically unstable and has an irregular VT rhythm.
Polymorphic has signs of torsades de pointes.
Slide 66+67
What is Ventricular fibrillation?
Chaotic ventricular electrical activity which causes the heart ot lose the ability to function as a pump. Slide 68
What is the acute and long term treatment of VT?
Acute
Unstable: Direct current cardioversion
Stable: Pharmacologic cardioversion.
Chronic Correct ischaemia Anti-arryhtmic drugs Implantable cardiovertor defibs. VT catheter ablation. Slide 69+70
What does an ICD do?
Termination the occurance of a VT or VF by defibirillation. Slide 72
