b

1. BY
ROBERT IGBEDE

2. In this disorder, accessory pathways form
and fail to disappear during fetal
development and this dormant tract is
known as the ATRIOVENTRICULAR
BYPASS TRACT
It is Formed near the mitral or tricuspid
valves or even interventricular septum
An AV bypass tract is sometimes referred
to as the bundle of Kent

3.  From SA node directly
to AV node AND to
ventricular
myocardium Partially
bypassing the bundle
of His and purkinje
fibers

5.  Wide QRS
 due to early
depolarization and not
due to a delay in
depolarization
 Shortened PR interval
 Upstroke QRS
complex is slurred;
delta wave

6. As a general rule: the initial QRS
complex (delta wave) vector will point
away from the area of the ventricles
that is first to be stimulated by the
bypass tract

7.  Left Lateral
negative delta waves in I and/or aVL and
positive in V1
 Posterior
positive delta waves in most of the
precordial (chest) leads and negative in the
inferior leads
 Right
negative delta waves in V1 and V2 and
positive in I and V6
 Anteroseptal (anterior)
negative delta waves in leads V1 and V2

8.  Unstable patient: DC cardioversion (calcium
blockers and beta blockers contraindicated)
 Stable patient: procainamide/amiodarone
(calcium blockers eg diltiazem and verapamil)
 Sodium channel blockers: Flecainide,
Etmozine, Etacizine, Propaphenone
 Surgical: Catheter ablation of accessory
pathways
 Asymptomatic patients are often monitored
and not treated

9.  WPW pattern: EKG findings (short PR interval
and delta wave) in the absence of symptoms
 WPW pattern: EKG findings (short PR interval
and delta wave) symptoms present
(arrhythmias involving the accessory
pathway)
 Most patients with WPW pattern never
develop WPW syndrome and they are both
variable in patients
 It may be constant, intermittent or disappear
permanently over time