Arrhythmias (done) Flashcards
How does a yung boi figure out the heart rate on an ECG
Count the number of large squares between the QRS complex to give you ‘X’
Divide 300 by ‘X’
Which type of arrhythmia is the most prevalent in hospital?
Atrial fibrillation
What is atrial fibrillation?
Chaotic electrical activity in the Atria causing fluttering muscle contractions of the atrial walls
What is the nature of an AFib rhythm and why?
Irregularly irregular
Chaotic nature of depolarisation of atria means conduction through the AV node is random
This means the ventricles contract randomly so you get irregular QRS complexes
Describe what an AFib ECG looks like
Fucking mental base line, but with irregularly irregular QRS complexes
Heart rate high but not baked as a cake, tends to be 100-175 bpm
The fact that there is still QRS complexes is important for telling between A fib and V fib etc
How does AFib present?
Often asymptomatic
if symptomatic then:
- Palpitations
- Dyspnoea SOB
- Chest pain
- Fatigue maybe dizziness
Can present with/due to complication
What risk is associated with AFib?
Embolism
Often manifesting in stroke
How do you investigate persistent AFib?
ECG - 12 lead, 24 hour recording
Blood test for hyperthyroidism
ECHO
How would you investigate paroxysmal AFib?
ECG event recorder = “Holter monitor” - ambulatory monitor that patient can wear which is more suitable if AFib is intermittent
Bloods - hyperthyroidism
ECHO
Why is thyroid levels in bloods important for AF investigation?
Hyperthyroidism can sometimes cause Arrhythmias
What surgical treatments are available for AFib?
Drug therapy is on the other deck
Radiofrequency catheter ablation:
- Ablation of AV node (+ implantation of pacemaker)
- Maze procedure
- Pulmonary vein ostial ablation
DC cardioversion is also an option (ICD)
How does AV-nodal re-entrant tachycardia (a type of SVT) present?
palpitations
dyspnoea
dizziness
What does Supraventricular tachycardia look like on an ECG?
Regular
HR over 100 but not mental
Shape of SVT is quite characteristic so look it up or something
Main features:
- S dip goes a wee bit lower than Q dip
- Single large wave between each complex
Overt AV re-entrant tachycardia is known as what?
Wolff-Parkinson-White syndrome
WPW
How is WPW / AV re-entrant tachycardia corrected?
Radiofrequency catheter ablation
Drug treatment is a bit iffy so doubt you’ll be asked about it
What is atrial flutter?
Type of SVT in which the atria has rapid contractions
However, it is not as chaotic as AFib
How does an ECG of Atrial flutter look?
Saw tooth P-wave appearance
Usually 1, 2 or 3 Saw tooth P waves between each QRS complex
What causes Atrial flutter?
Re-entry loop in the right atrium which includes the “Cavotricuspid isthmus”
The loop causes rapid aortic contractions, but the AV node’s long refractory period means some of them aren’t conducted down to the Ventricles
How is Atrial flutter treated?
Drugs - Control ventricular rate & thromboembolic risk
Usually cardiovert
Prevent with AA drugs or RFA of cavotricuspid isthmus
What is ventricular fibrillation?
Rapid uncoordinated squirming contractions of the ventricles
Caused by a re-entrant loop in the ventricle
How does VFib present?
Presents often as cardiac arrest - patient seriously unwell
How is VFib treated?
Cardiac arrest protocol
Defibrillation & CPR
IV adrenaline 100microg and amiodarone if needed
How does Vfib look on an ECG?
Fucking mental
No recognisable waves - just a big mess
How does Ventricular Tachycardia present?
Palpitations Chest Pain Dyspnoea Dizziness Syncope
How is VT investigated?
ECG
Bloods (Thyroid)
ECHO
Angiogram
What causes long QT syndrome?
Repolarisation phase is abnormally long in some of their heart cells
This means the time taken for the T wave to occur (which is caused by repolarisation) is longer
What causes long QT syndrome?
Congenital or acquired
What can be caused by long QT syndrome?
Torsades de Pointes
How would you identify TdP on an ECG?
Short-long-short intervals between QRS complexes
What are the indications for a patient to receive an ICD?
Cardiac arrest due to VF/VT not due to transient or
reversible cause eg early phase of acute MI
Sustained VT causing syncope or significant compromise
Sustained VT with poor LV function
“Sick sinus rhythm” can happen to someone after what?
MI
What is Sick sinus rhythm?
asymptomatic SA node suppression
Occasional really long gaps between heart beats
What are the indications for temporary pacing?
intermittent or sustained symptomatic bradycardia,
particularly syncope
prophylactic when patient at high risk for development of severe bradycardia eg 2nd or 3rd degree AV block, post anterior MI, even when asymptomatic
What are the indications for permanent pacing?
Symptomatic or profound 2nd/3rd degree AV block,
particularly when cause is unknown ± unlikely to disappear
Probably Mobitz type II 2nd/3rd degree AV block even if asymptomatic
AV block associated with neuromuscular diseases
After (or in preparation for) AV-node ablation
alternating RBBB/LBBB
syncope when bifascicular/trifascicular block and no other explanation
sinus node disease associated with symptoms
carotid sinus hypersensitivity/malignant vasovagal syncope
What does first degreeHeart block look like on an ECG?
Long PR interval > 200ms
What does Mobitz (2D) type 1 heart block look like on an ECG?
PR interval progressively grows until dropped beat
What does Mobitz (2D) type 2 heart block look like on an ECG?
Occasional dropped QRS complex/beat but with consistent PR intervals
What does third degree (complete) heart block look like?
P waves are regular and consistent and QRS complexes are also regular
But P waves and QRS complexes have no relation to each other as there is no conduction of depolarisation
So PR intervals are completely random
