Spotter of the week

07 JUL 2016

What Dr.Shihana says ?

Dr Remya A S

WPW SYNDROME

Described by Louis Wolff, John Parkinson and Paul Dudley White in 1930
It is an pre excitation syndrome characterised by AV conduction through a bypass tract that results in earlier activation of the ventricles than through the AV node
Most common preexcitation syndrome
Classic pathway is the Kent pathway
Others are the James / Brechenmacher and Mahaim tracts

EPIDEMIOLOGY
Overall incidence : 3.96/100000 persons/year
Most cases are sporadic
Bimodal age distribution – 1st year and then young adulthood
Autosomal inheritance pattern

Types
Orthodromic
Antidromic

CLINICAL FEATURES
Palpitations
Mild Weakness
Dizziness
Mild chest pain
Breathing difficulty
Syncope

Complications
Tachyarrhythmias
Sudden cardiac death

ECG Findings
Short PR Interval (<120 ms)
Wide QRS complex longer than 120 ms
Slurred onset of QRS waveform producing a delta wave in early part of QRS
Secondary ST – T wave changes

Other Investigations
Stress testing
Electrophysiological study to determine :
Mechanism of clinical dysrhythmia
Conduction capabilities and refractory periods of the pathways
Number and locations of Aps
Response to pharmacological or ablation therapy

Caution
Usual presentations are SVT
Narrow Complex AVRTs and AVNRTs :
Vagal Maneuvers
IV Adenosine 6-12mg
IV Verapamil 5-10mg / Diltiazem 10mg    

Drugs to be avoided in WPW with AF :
Adenosine
Beta blockers
Calcium channel blockers
Digoxin

Treatment
Class 1c (Flecainide) and Class 3 (Ibutilide)
Slows AP conduction facilitating blockage of SVT
Radiofrequency ablation is the treatment of choice
>90% success rates