Arrhythmias Flashcards
What are the two classes of arrhythmias described by where the arrhythmia arises?
Supraventricular
Ventricular
Supraventricular arrhythmias tend to have narrow QRS complexes. True/False?
True
Because the arrhythmia does not originate from ventricles
What are ectopic beats? How are they treated?
Beats/rhythms that originate outwith the SA node - typically present as palpitations
Avoid stimulants, B blockers, nothing
Ectopic beats may not be dangerous. True/False?
True
Why might ectopic beats not be harmful?
Depends on where they originate - if in non-contractile areas, they are unlikely to affect cardiac output
Name the main supraventricular arrhythmias
SVTs: atrial fibrillation (atria beat rregularly), atrial flutter (atria beat regularly but faster than usual), ectopic atrial tachycardia
Bradycardias: sinus bradycardia (<60 bpm), sinus pauses (SAN doesnt stimulate impulse)
Name the main AV node arrhythmias
AV node reentry Accessory pathway AV block (1st, 2nd, 3rd degree)
Name the main ventricular arrhythmias
Premature ventricular complex (ectopic beat from purkinje fibres)
Ventricular tachycardia
Ventricular fibrillation
Asystole
What are the 3 main physiological types of arrhythmia?
Altered automaticity
Triggered activity
Reentry (accessory pathway)
List the investigations you would do for arrythmias
ECG/exercise ECG/24hr ECG CXR Echo Event recorder EP study (induce arrhythmia to map pathway)
How would acute SVT be managed?
Vagal manoeuvres, carotid massage, IV adenosine, IV verapamil
Give examples of some vagal manoeuvres
Holding your breath and bearing down (Valsalva)
Immersing face in ice-cold water (diving reflex)
Holding nose/unblocking ears
What is the treatment of choice for managing chronic arrhythmias?
Radiofrequency ablation
What is radiofrequency ablation?
Selective cauterisation of cardiac tissue to prevent tachycardia
Target reentry circuit or automatic myocite
Which drugs must be stopped before radiofrequency ablation?
Antiarrhythmic drugs 3-5 days beforehand
What is notorious for causing AV block in young people?
Cytomegalovirus
Describe 1st degree AV block
PR interval increased (greater than 0.2s)
Describe 2nd degree Mobitz 1 AV block
PR interval gets progressively longer, followed by dropped QRS
Describe 2nd degree Mobitz 2 AV block
Lonely P waves not followed by QRS - QRS wave dropped every nth time
N.B. PR interval not prolonged
Describe 3rd degree AV block
P waves without QRS complexesi.e. no association between atrial and ventricular systole
What is typical of an ECG showing ventricular tachycardia?
Broad QRS complexes
What is the difference between monomorphic and polymorphic VT?
In monomorphic VT, the QRS complexes look similar
Polymorphic is disorganised (Torsades de Pointes)
How would acute VT be treated?
DC cardioversion if unstable
Adenosine if unsure it’s VT
What are the 3 classifications of AF?
Paroxysmal
Persistent
Permanent
Define paroxysmal AF
Recurrent AF, lasting less than 48 hours
Define persistent AF
AF lasting greater than 48 hours which can be cardioverted to normal sinus rhythm
Define permanent AF
AF that is unable to be restored to normal sinus rhythm via pharma + non pharmacological methods
What is meant by lone AF?
AF where a cause cannot be found
What would a typical ECG of AF show?
Rate greater than 300bpm
Irregularly irregular
P waves absent
What are the two management pathways for AF patients? What must you always consider?
Rhythm control (get back to NSR) Rate control (accept AF, control ventricular rate) ANTICOAGULATION
What pharmacological therapy can be used for rate control in AF?
Digoxin
B blockers
Verapamil
How can NSR be restored in AF (rhythm control)?
Amiodarone
Class I and III anti-arrhythmics
DC cardioversion
Class I anti-arrhythmic drugs act on which phase of the AP and block which channels?
Act on phase 0 - increase time spent in open and inactivated states to normalise beating frequency
Block Na+ channels
Name a class I anti-arrhythmic drug
1C: slow rate - Flecainide
1B: rapid rate - Lignocaine
1A: moderate rate - Disopyramide
Class II anti-arrhythmic drugs act on which phase of the AP and block which channels?
Act on phase 4
Block B receptors (B blockers)
Class III anti-arrhythmic drugs act on which phase of the AP and block which channels?
Phase 3
Block K channels
Name a class III anti-arrhythmic drug
Amiodarone
Sotalol
Class IV anti-arrhythmic drugs act on which phase of the AP and block which channels? Give an example
Phase 2
Block Ca channels
Verapamil
What would a typical ECG of atrial flutter look like?
Saw tooth baseline
Regular rhythm
What are the typical symptoms of arrhythmia?
Palpitations SOB Dizziness Syncope/pre-syncope (faintness) Chest pain Fatigue Sweatiness Worsening angina, CHF
In what situation is sinus bradycardia normal? How is it treated?
Athletes
Atropine acutely
Pacing if haemodynamic collapse
In what situation is sinus tachycardia normal? How is it treated?
Anxiety, fever, hypotension, anaemia
B blockers, change medications
What would Wolf Parkinson White syndrome look like on an ECG?
Broad QRS with slurred upstroke on R wave
‘Delta wave’
How is heart blocked treated?
Ventricular pacing
What are some causes of AF?
Heart surgery Hypertension Alcohol abuse Coronary HD Thyroid D Obesity/ athletes Valvular HD Familial
What score is used to estimate the need for anticoagulation in AF?
CHAD2VASC score
What would hyperkalaemia look like on an ECG?
Tall tented T waves
Wide QRS
What is the most common cause of sudden cardiac death in young people?
Hypertrophic cardiomyopathy
What drugs are used most commonly in SV arrhythmias?`
Adenosine
Digoxin
Verapamil
What drug is used most commonly in V arrhythmias?
Amiodarone
Lignocaine
What are some common side effects of anti-arrhythmic drugs?
Phototoxicity
Pulmonary fibrosis
Peripheral neuropathy
Thyroid abnormalities
