SV-Tachycardias (WPW syndrome & PSVT) Flashcards
1
Q
Tachycardias (WPW Syndrome & PSVT): Definition
A
Wolff-Parkinson-White syndrome:
- Accessory pathways (myocardial fibres extending from atria to ventricles) pre-excite the ventricle - obv causing inc HR
- ie. conduction from the atrium reaches the adjacent ventricle earlier via the AP, and a part of the ventricle is pre-excited.
- The term WPW syndrome is restricted to symptomatic patients with typical ECG abnormality
- whereas the term WPW pattern signifies an asymptomatic patient with typical ECG abnormalities
PSVT
- a type of supraventricular tachycardia, named for its intermittent episodes of abrupt onset and termination
2
Q
Tachycardias (WPW Syndrome & PSVT): Aetiology
A
WPW
- WPW pattern on ECG arises from a developmental cardiac defect in the atrioventricular (AV) electrical insulation at the AV groove due to the presence of an accessory pathway (AP).
- These APs are usually single epicardial strands of tissue that travel across the AV groove to connect the atrium and the adjacent ventricular myocardium.
PSVT
- The cause is not know
- But the underlying mechanism ‘typically involves an accessory pathway that results in re-entry’
3
Q
Tachycardias (WPW Syndrome & PSVT): Risk factors
A
WPW
- Ebstein’s anomaly (picture attatched)
- a congenital heart defect in which the septal and posterior leaflets of the tricuspid valve are displaced towards the apex of the right ventricle of the heart
- hypertrophic cardiomyopathy
- mitral valve prolapse
- atrial septal defect
PSVT
- cause is unknown so risk factors difficult to find
- I imagine it’s a congenital structural heart defect like in WPW
4
Q
Tachycardias (WPW Syndrome & PSVT): Pathophysiology
A
I’m going to re-insert aetiology here because step by step pathophysiology isn’t clear
WPW
- WPW pattern on ECG arises from a developmental cardiac defect in the atrioventricular (AV) electrical insulation at the AV groove due to the presence of an accessory pathway (AP).
- These APs are usually single epicardial strands of tissue that travel across the AV groove to connect the atrium and the adjacent ventricular myocardium.
PSVT
- The cause is not know
- But the underlying mechanism ‘typically involves an accessory pathway that results in re-entry’
5
Q
Tachycardias (WPW Syndrome & PSVT): Cinical manifestations: key presentations, other symptoms and signs
A
WPW
- palpitations
- dizziness
- shortness of breath
- chest pain
- sudden cardiac death
PSVT
- palpitations
- feeling lightheaded
- sweating
- shortness of breath
- chest pain
6
Q
Tachycardias (WPW Syndrome & PSVT): Investigations (diagnosis): 1st line, gold standard & other
A
ECGs all round
WPW
- Delta wave: slurred upstroke in the QRS (seen in attatched pic), in WPW is associated with a short PR interval
- Broad QRS
PSVT
- narrow QRS complexes and a fast heart rhythm typically between 150 and 240 beats per minute.
7
Q
Tachycardias (WPW Syndrome & PSVT): DDx
A
- I think just any other arrhythmia due to dodgy ECG (artifacts etc)
8
Q
Tachycardias (WPW Syndrome & PSVT): Management
A
WPW
- Treatment of acute presentations is based on the nature of the arrhythmia.
- Ongoing treatment is decided according to the symptoms of the patient as well as risk stratification for sudden cardiac death
- may require synchronized electrical cardioversion
- Antiarrhythmic medication
-
AV node blockers should be avoided
- They can exacerbate the syndrome by blocking the heart’s normal electrical pathway (therefore favoring 1:1 atrial to ventricle conduction through the pre-excitation pathway, potentially leading to unstable ventricular arrhythmias)
- definative treatment:
- destruction of the abnormal electrical pathway by radiofrequency catheter ablation
PSVT
- Vagal maneuvers, such as the Valsalva maneuver, are often used as the initial treatment
- If not effective and the person has a normal blood pressure the medication adenosine may be tried
- Next, CCB or BB
- Otherwise synchronized cardioversion is the treatment
- Future episodes can be prevented by catheter ablation
