Arrhythmias Flashcards
1) Name 2 cardiac causes of arrhythmias
2) Name 2 non-cardiac causes of arrhythmias
3) Name 2 ways arrhythmias may present as
1) Ischaemic heart disease, structural changes to the heart, cardiomyopathies, pericarditis, myocarditis
2) Caffeine, smoking, alcohol, pneumonia, drugs (beta2 agonists, digoxin, L-dopa, tricyclics, doxorubicin), metabolic imbalances (K+, Ca2+, Mg2+, hypoxia, hypercapnia, metabolic acidosis, thyroid disease) and pheochromocytoma
3) Palpitations, chest pain, syncope, hypotension, pulmonary oedema
What is sick sinus syndrome and what causes it?
Sick sinus syndrome is when the SA node becomes dysfunctional which sometimes leads to bradyarrhythmias and sometimes leads to tachyarrhythmias. It’s usually caused by scarring or fibrosis of the SA node.
What is the definition of a narrow complex tachycardia?
When an ECG shows a rate of >100bpm and the QRS complex duration is <120ms
Sinus tachycardia
1) Comment on the rhythm and QRS complex of sinus tachycardia
2) What is sinus tachycardia with no known reason called?
3) Name a cause of this type of sinus tachycardia
4) Name 2 potential causes of sinus tachycardia
5) What 2 groups of drugs can be used to treat sinus tachycardia
1) Regular rhythm, narrow QRS
2) Inappropriate sinus tachycardia
3) Autonomic neuropathy
4) Systemic vasodilation, fever, anaemia, dehydration, drugs (i.e. caffeine, salbutamol, nicotine), hyperthyroidism, pregnancy
5) CCBs and beta blockers
Focal atrial tachycardia
1) Comment on the rhythm and QRS complex in focal atrial tachycardia
2) What causes focal atrial tachycardia?
3) How does focal atrial tachycardia appear differently on an ECG than sinus rhythm?
1) Regular rhythm, narrow QRS
2) A group of atrial cells act as a pacemaker, but these group of cells outpace the SA node
3) P wave morphology is different
Atrial flutter
1) Comment on the rhythm and QRS complex of atrial flutter
2) What is the classic appearance of atrial flutter on ECG?
3) What causes atrial flutter?
4) Name 3 causes of atrial flutter
5) The treatment of atrial flutter is similar to what other condition?
6) If a patient with atrial flutter is unstable, what method of cardioversion - direct current or pharmacological - is preferred?
7) As recurrence rates are high in atrial flutter, what is often recommended for long term management?
1) Regular rhythm, narrow QRS
2) Sawtooth
3) A re-entrant circuit causes electrical activity to circle the atria at 300bpm. Some of these of these impulses pass through the AVN resulting in ventricular rates that are factors of 300
4) Hypertension, heart failure, ischaemic heart disease, COPD, PE, hyperthyroidism
5) AF
6) Direct current cardioversion
7) Radiofrequency ablation
Types of supraventricular tachycardias (SVTs)
1) What are the 3 main types of SVTs?
2) Generally, what causes these types of arrhythmias?
3) Comment on the rhythm and QRS complex of SVTs
4) What is paroxysmal SVT?
5) What are the 3 non-pharmacological ways of managing SVTs?
6) What is the pharmacological way of managing SVTs, and what is the alternative drug group. Name an example when the 1st line is contraindicated therefore the 2nd line would be used?
7) What is the non-pharmacological long term management of paroxysmal SVT, and what 3 drug/drug groups that can be used in the pharmacological long term management of SVT?
1) Atrioventricular nodal re-entrant tachycardia (AVNRT), atrioventricular re-entrant tachycardia (AVRT) and atrial tachycardia
2) Electrical signals re-entering the atria from the ventricles, travelling back through the AV node to cause another ventricular contraction
3) Regular rhythm and narrow QRS
4) An SVT that occurs and remits in the same patient over time
5) Continuous ECG monitoring, Valsalva manoeuvre and carotid sinus massage
6) Adenosine as rapid IV bolus dose, non-dihydropyridine CCB i.e. verapamil. Adenosine is contraindicated in asthma
7) Cardiac ablation. Amiodarone, CCB, beta blocker
Atrioventricular re-entrant tachycardia (AVRT)
1) What causes an AVRT?
2) What is the direction of this conduction called?
3) Comment on the rhythm and QRS complex that conduction going in this direction generates
4) What is it called when the direction of conduction is the opposite?
5) Comment on the QRS complex that conduction going in this direction generates
1) An accessory pathway allows electrical activity from the ventricles to pass to the resting atrial myocytes, which generates a circuit.
2) Orthodromic
3) Regular rhythm, narrow QRS
4) Antidromic
5) Broad QRS
Atrioventricular nodal re-entrant tachycardia (AVNRT)
1) What causes AVNRT?
1) Electrical signals re-entering the atria through the AV node to cause another ventricular contraction
Ventricular tachycardia (VT)
1) Comment on the rhythm and QRS complex in VT
2) Name 2 causes of VT
3) How is VT treated to restore sinus rhythm?
4) What is administered if this fails?
1) Regular rhythm, broad QRS
2) Electrolyte abnormalities, structural heart disease i.e. MI, drugs that cause QT prolongation i.e. clarithromycin, and channelopathies i.e. Brugada syndrome
3) DC cardioversion
4) IV amiodarone
Torsades des Pointes (TdP)
1) Comment on the rhythm and QRS complex
2) What type of arrhythmia is TdP, and what ECG feature is it associated with?
3) Name a cause of a long QT interval (which may predispose a patient to developing TdP)
4) How is TdP managed in stable patients?
5) How is TdP managed in unstable patients?
1) Irregular rhythm, wide QRS
2) Polymorphic ventricular tachycardia - long QT interval
3) Toxins i.e. drugs such as clarithromycin, TCAs and antiarrhythmics, ischaemia, myocarditis, electrolyte abnormalities, mitral valve prolapse and inherited long QT syndromes i.e. Romano Ward syndrome, subarachnoid haemorrhage
4) IV magnesium sulphate
5) DC cardioversion
Ventricular fibrillation
1) Comment on the rhythm (2) and QRS complex (2)
2) When does it most commonly occur, and name another occasion that it may occur in
3) The first aspect of management = BLS (chest compressions to ventilation 30:2), and then unsynchronised defibrillator shocks - how many unsuccessful shocks are given before medication are given?
4) What are the 2 medication given, how are they given, and what are their doses?
1) Irregular and pulseless rhythm, wide and polymorphic QRS
2) During or shortly after an MI. Electrolyte imbalances and genetic conditions i.e. brugada syndrome
3) 3
4) Adrenaline (1mg) and adenosine (300mg). Both IV
Wolff Parkinson White syndrome (type of AVRT)
1) What are the 3 ECG changes that is seen in WPW syndrome?
2) What causes WPW syndrome?
3) How is it treated?
4) Most antiarrhythmic drugs are contraindicated in patients with WPW syndrome that also develop what other arrhythmia?
5) What is the reason for these drugs being contraindicated?
1) Wide QRS, short PR interval, delta wave (slurred upstroke of QRS)
2) Accessory pathway connecting the atria and the ventricles called the bundle of Kent
3) Cardiac ablation
4) AF or atrial flutter
5) These drugs reduce conduction through the AV node, however in WPW syndrome this would promote conduction through the accessory pathway (bundle of Kent) which can cause a polymorphic wide complex tachycardia - ventricular fibrillation
Brugada syndrome
1) This is an autosomal dominant genetic condition caused by what?
2) Which group of people is this condition more common in?
3) Name a risk factor that increases the chances of an individual with brugada syndrome developing an arrhythmia
4) What is the investigation of choice, and why is it used?
5) How is it treated?
1) Sodium channelopathies
2) Males of Asian ethnicity
3) Fever, dehydration, excess alcohol intake
4) Flecainide - it makes the ECG changes more apparent
5) Implantable cardioverter defibrillator (ICD)
Cardiac arrest rhythms
1) What are the 4 cardiac arrest rhythms?
2) Which of these are shockable (defibrillator should be used)?
3) Which if these are unshockable (defibrillator should not be used)?
1) VT (pulseless), VF, asystole, pulseless electrical activity
2) VT (pulseless) and VF
3) Asystole, pulseless electrical activity
