Atrial arrhythmias (CVS) Flashcards
What are arrhythmias?
Arrhythmias are abnormal heart rhythms. They result from an interruption to the normal electrical signals that coordinate the contraction of the heart muscle.
What are the general symptoms of an arrhythmia?
Palpitations, dizzy, syncope, shortness of breath
What are the two basic divisions of arryhthmias?
They can be divided into bradycardias and tachycardias.
How are bradycardias divided?
Sinus bradycardia or heart block. Heart block can then be either AV block or bundle branch block. Bundle branch block can be left or right.
What are the 3 divisions of tachycardias?
SVT, Ventricular, atrial. (and sinus)
Types of ventricular arrhythmias?
Ventricular fibrillation and ventricular tachycardia
Types of Supraventricular tachycardias?
Atrioventricular nodal reentrant tachycardia (AVNRT). Atrioventricular reciprocating tachycardia (AVRT).
Types of atrial tachyarrhythmias?
Atrial fibrillation, atrial flutter and atrial tachycardia
How are arrhythmias divided in terms of their wave structure?
QRS complex size - can be either narrow or broad. Narrow QRS usually indicate supraventricular arryhtmias while broad indicate ventricular arryhtmias or SVT + conduction problems
Examples of arryhthmias with narrow QRS
Atrial flutter, AF, AVNRT, AVRT, atrial tachycardia
Examples of broad QRS complex arryhtmias?
Ventricular tachy, toursafes de pointes, vent fibrillation, aberrant conduction (e.g. SVT + BBB)
What is atrial flutter?
It is an atrial arrhythmia (technically characterised under SVT) - characterised by a rapid, regular atrial rate (300bpm) and vent rate fixed or variable, that causes symptoms
Risk factors of atrial flutter
Older age, hypertension, diabetes, heart diseases, obesity, Hx of AF. Pulmonary disease with these RFs increases risk even more.
How does atrial flutter happen (aetiology)?
Caused by a re-entrant circuit in either of the atria. It activates AV node however AVN has long refractory period so can’t conduct down bundle of his to the vents at same fast rate. Tf ratio of atrial contraction and vent should be 1:1 but is instead 2 or 3 or 4:1.
What are the clinical features of atrial flutter?
It can be asymptomatic however can include palpitations, lightheadedness, syncope, chest pain. Atrial rate of 300bpm.
What are the differentials of atrial flutter?
AF (ECG needed to distinguish), SVT (ECG also needed), VT (ECG patterns differs)
What does the ECG show for atrial flutter?
Regular rhythm, sawtooth pattern of P waves at 300bpm, narrow QRS complexes, vent rate can be 2, 3 or 4:1 and/or may be variable. When there is variable AVN block, this can make it hard to distinguish between AF.
What is the management of atrial flutter in haemodynamically unstable pts (and signs of the instability)?
Signs are shock (end organ ischemia), syncope (cerebral hypoperfusion), chest pain (myocardial ischemia), pulmonary oedema (sign of HF). For these pts, 1st line is direct current synchronised cardioversion +/- amiodarone.
What is the management of atrial flutter in haemodynamically stable pts?
Fluid rehydration in septic or dehydrated patients. For rate and rhythm control, 1st line is beta blocker (bisoprolol) or calcium channel blocker (diltiazem, verapamil). If rate control fails, consider cardioversion. If this fails or recurrent episodes - ablation at tricuspid valve isthmus (high success rate).
Complications of atrial flutter?
Increased risk of ischemic stroke - consider anti coagulation using same AF guidance
What are the two main types of supraventricular tachycardias and briefly explain pathophysio
Atrioventricular re entry tachycardia (AVRT) - this is where re entrant circuit is via an accessory pathway. AV nodal re entry tachycardia (AVNRT) - this is where the re entry circuit is within the AV node. They are narrow QRS.
What is the Ix and acute management of AVRT and AVNRT?
ECG. Pts with signs of haemodynamic instability (chest pain, confusion, hypotension, syncope, pale, clammy, cold hands) - DC shocks/cardioversion. Pts that are stable - if irregular rhythm then treat like AFib, if regular then vagal manoeurvres (such as valsalva manoeuvre or carotid sinus massage) and if this doesnt work then IV adenosine.
What is wolff parkinson white syndrome?
A congenital pre-excitation syndrome that occurs due to the presence of an accessory electrical pathway between the atria and ventricles - predisposes to AVRT. Often asymptomatic or may otherwise have typical arrhytmic symptoms.
Investigations for wolff parkinson white syndrome?
Resting ECG shows delta waves (slurred upstroke in QRS), short PR interval and broad QRS. If a re entrant arrhtyhmia occurs (AVRT) then ECG will show narrow QRS. If paroxysmal symptoms, do 24 hr ECG. Echo - assesses vent function. Routine bloods (incl thyroid function tests)
What is the emergency management of wolff parkisnosn white syndrome also presenting with SVT?
Same as SVT - unstable pt give DC cardioversion, stable pt with regular rhythm do vagal manouvres if doesnt work then V adenosine, if still doesnt work then cardioversion. If irregular - treat as AFib.
What is long term management of wolff parkinsons white syndrome?
Catheter ablation, drug treatment e.g. amiodarone or sotalol
