Wolff-Parkinson-White Syndrome Flashcards
What is Wolff-Parkinson-White syndrome?
Occurs when one or more strands of myocardial fibres capable of conducting electrical impulses (known as accessory pathways [APs] or bypass tracts) connect the atrium to the ipsilateral ventricle across the mitral or tricuspid annulus. Conduction from the atrium reaches the adjacent ventricle earlier via the AP, and a part of the ventricle is pre-excited.
What is the Bundle of Kent?
An accessory pathway that conducts impulses from the atria to the ventricles). The bundle of Kent connects the atria and ventricles, bypassing the AV node and leading to a pre-excitation of the ventricles.
Which condition do 1/3 of Wolff-Parkinson-White patients go onto develop?
Paroxysmal atrial fibrillation
How do Wolff-Parkinson-White syndrome and Wolff-Parkinson-White pattern differ?
- Wolff-Parkinson-White (WPW) syndrome: is restricted to symptomatic patients with a typical ECG abnormality.
- Wolff-Parkinson-White pattern: signifies an asymptomatic patient with typical ECG abnormalities.
What risk factors are associated with Wolff-Parkinson-White syndrome?
Congenital cardiac abnormalities. The most common is Ebstein’s anomaly.
What are the symptoms of Wolff-Parkinson-White syndrome?
- Palpitations
- Dizziness
- Dyspnoea
- Chest pain
What are the signs of Wolff-Parkinson-White syndrome?
- Atrial fibrillation
- Atrial flutter
- Congenital cardiac abnormalities
What investigations should be ordered for Wolff-Parkinson-White syndrome?
- 12-lead ECG
Why investigate a 12-lead ECG? And what may this show?
- ECG should be recorded in any patients with suspected supraventricular arrhythmia.
- Delta waves signify presence of an antegradely conducting AP; no delta waves can mean a concealed retrograde-only AP or an AP with intermittent pre-excitation.
Briefly describe the treatment for asymptomatic Wolff-Parkinson-White Syndrome
While controversy exists, most experts recommend that all patients with ventricular pre-excitation undergo risk stratification to determine their risk of sudden cardiac death, regardless of the presence of symptoms.
Asymptomatic patients in specialised jobs with particular safety issues (e.g., airline pilot, school bus driver) can be considered for catheter ablation. Catheter ablation is also performed in asymptomatic patients who are found to have a ‘high-risk’ accessory pathway at the time of electrophysiology testing.
Briefly describe the treatment for symptomatic Wolff-Parkinson-White Syndrome
Symptomatic patients usually undergo catheter ablation as a first-line therapy.
Anti-arrhythmic drugs are one of the therapeutic options for the management of symptomatic WPW syndrome, but they have been increasingly replaced by catheter ablation.
Briefly describe the treatment for stable acute Wolff-Parkinson-White Syndrome
Dependent on if classfied as orthodromic AV reciprocating tachycardia (narrow complex with short RP tachycardia), antidromic AV reciprocating tachycardia (wide complex tachycardia) or whether they have atrial fibrillation, flutter, or tachycardia.
- Narrow: carotid sinus massage or Valsalva manouvere
- Wide: IV adenosine or anti-arrthymics
- Atrial fibrillation, atrial flutter or tachycardia: anti-arrthymics
Briefly describe the treatment for unstable acute Wolff-Parkinson-White Syndrome
Patients with an acute tachycardia and who are haemodynamically unstable (BP <90/60 mmHg, with signs of systemic hypoperfusion) or who have atrial fibrillation with >250 bpm, or in whom the atrial fibrillation has degenerated to ventricular fibrillation, require immediate DC cardioversion.
What complications are associated with Wolff-Parkinson-White Syndrome?
- Sudden cardiac death
What differentials should be considered in Wolff-Parkinson-White Syndrome?
- Atriofasicular pathway
- Nodofasciular pathway
- Fasiculoventricular pathway
Briefly describe the rare forms of accessory pathways occur due to various anatomical substrates with different ECG manifestation
Note: differentials for Wolff-Parkinson-White syndrome
Atriofasciular pathway: baseline ECG normal. On electrophysiological study, the pathway will be located at right lateral tricuspid annulus to right ventricular apex.
Nodofasciular pathway: baseline ECG shows short PR interval, but no delta wave. On electrophysiological study, there will be a pathway from atrioventricular node to the ventricle.
Fasiculoventricular pathway: baseline ECG shows short PR, narrow QRS, and delta wave. On electrophysiological study, there will be a His bundle or bundle branch to the ventricle.
