SV-Tachycardias: (A flutter & A fib)

Question 1

SV-Tachycardias: (A flutter & A fib): Definition

Answer 1

• flutter: (of a bird or winged creature) to fly unsteadily or hover by flapping the wings quickly or lightly
• Therefore, atrial flutter is a condition where the atria beat regularly, but faster than usual and more often than the ventricles, so you may have four atrial beats to every one ventricular beat
• fibrillation: (of a muslce, especially in the heart) make a quivering movement due to uncordinated contraction of the individual fibrils
• Therefore, atrial fibrillation is a condition that causes an irregular, and often fast, heartbeat
• Afib is the most common serious abnormal heart rhythm
• So, the difference is that in Aflutter the atria beat regularly whereas in Afib the atria beat irregularly - and they both involve tachyarrhythmia
• Also, Afib may start as other forms of arrhythmia such as Aflutter that then transform into AF

Question 2

SV-Tachycardias: (A flutter & A fib): Aetiology

Answer 2

• I think both can be caused by similar things; various cardiac conditions:
  
  • HTN
  • Valvular heart disease
  • heart failure
  • coronary artery disease
  • cardiomyopathy
  • congenital heart disease
  • structural abnormalities of the heart
    
    • may be idiopathic atrial fibrosis
    • may be due to scars from atrial surgery or prior atrial ablation sites
• Afib is linked to several forms of cardiovascular disease but may occur in otherwise normal hearts

Question 3

SV-Tachycardias: (A flutter & A fib): Risk factors

Answer 3

• Same at aetiology really
  
  • HTN
    
    • therefore obesity etc
  • valvular heart disease
    
    • therefore genetics
  • heart failure
  • coronary artery disease
  • cardiomyopathy
  • congenital heart disease
  • structural abnormalities of the heart
  • may be idiopathic atrial fibrosis
  • may be due to scars from atrial surgery or prior atrial ablation sites

Question 4

SV-Tachycardias: (A flutter & A fib): Pathophysiology

Answer 4

• Specifics depends on aetiology
• Aflutter
  
  • Typically initiated by a premature electrical impulse arising in the atria
  • atrial flutter is propagated due to differences in refractory periods of atrial tissue.
  • This creates electrical activity that moves in a localized self-perpetuating loop, which usually lasts about 200 milliseconds for the complete circuit.
  • For each cycle around the loop, an electric impulse results and propagates through the atria
• Afib
  
  • The primary pathologic change seen in Afib is the progressive fibrosis of the atria - fibrosis may also occur in SA or AV node
    
    • this fibrosis can be caused by many of the range of Afib aetiologies
  • In AFib, the normal regular electrical impulses generated by the sinoatrial node are overwhelmed by disorganized, rapid electrical discharges produced in the atria and adjacent parts of the pulmonary veins.
  • These disorganized waves conduct intermittently through the atrioventricular node, leading to irregular activation of the ventricles that generate the heartbeat.

Question 5

SV-Tachycardias: (A flutter & A fib): Cinical manifestations: key presentations, other symptoms and signs

Answer 5

• Aflutter
  
  • can sometimes go unnoticed
  • but people may notice their heart beating too fast/ hard until the episode is over or the HR is controlled
  • if Aflutter is due to aetiology like CAD, patients may experience the related symptoms and Aflutter will be noticed on ECG
• Afib
  
  • can be symptomless
  • similar to Aflutter in the sense that patient may simply realise their heart is beating too fast or hard
  • occasionally may produce anginal chest pain (if the high heart rate causes the heart’s demand for oxygen to increase beyond the supply of available oxygen (ischemia))
  • beyond the above, as Afib is often secondary to other conditions, symptoms of angina/ lung disease/ hyperthyroidism can also be present

Question 6

SV-Tachycardias: (A flutter & A fib): Investigations (diagnosis): 1st line, gold standard & other

Answer 6

• Both conditions will often be noticed on ECG during investigation of conditions that are causing more sig symptoms than the Afib or Aflutter alone, ie. CAD/ ischaemia-angina
• Afib
  
  • Irregularly irregular QRS complexes
  • Absence of P waves
  • QRS usually < 120ms unless patient has other conducting problems
  • ECHO if suspected valvular disease
• Aflutter
  
  • Organised ‘sawtooth pattern’
  • Important factor is a regular beat
  • Murmurs or rubs on auscultation suggest valvular disease, pericarditis, or congenital heart disease

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Question 7

SV-Tachycardias: (A flutter & A fib): DDx

Answer 7

• Aflutter
  
  • other supraventricular tachycardias
  • Afib
• Afib
  
  • atrial flutter
  • atrial tachycardia
  • paroxysmal supraventricular tachycardia
  • Wolff-Parkinson-White syndrome

Question 8

SV-Tachycardias: (A flutter & A fib): Management

Answer 8

• In general, Aflutter should be managed in the same way as Afib
  
  • bc both rhythms can lead to atrium clot formation, so,
    
    • anticoagulation agents
    • antiplatelet agent
• Both rhythms can be associated with dangerously fast heart rates and thus require medication to control the heart rate
  
  • beta blockers
  • calcium channel blockers
• and/or rhythm contro
  
  • with class III antiarrhythmics (such as ibutilide or dofetilide)
• Hemodynamically Unstable due to uncontrolled tachycardia:
  
  • immediate heparin
  • attempted cardioversion with synchronised DC shock
• Hemodynamically Stable: ​​​
  
  • Anti-coagulation (red stroke risk)
  • Rate control - patient not in severe tachycardia but will still have Afib rhythm
    
    • BBs are first line
    • CCBs or Digoxin are second line
  • Rhythm control - returns to sinus rhythm, given to patients with reversible causes, or new onset of Afib, achieved by cardioversion
    
    • Pharmacological Cardioversion - amiodarone
    • Electrical cardioversion - controlled shock delivered
• Long term BBs for rate and rhythm control
• Definitive treatment is catheter ablation