الفهرس 
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Abstract
Introduction:
Atrial fibrillation occurs in approximately 40-50% of patients with
Wolf-Parkinson-White syndrome, and in approximately 20% is the
presenting arrhythmia.
For unclear reasons, patients with overt preexcitation do have a
higher incidence of atrial fibrillation than those with with concealed
bypass tracts despite comparable locations and tachycardia cycle lengths.
These findings is also true for patients with atrio-ventricular reentrant
tachycardia (AVNRT).
Of interest, in most cases, initiation of atrial fibrillation begins in
the right atrium, a site usually far removed from the atrial insertion of the
bypass tract. This makes one wonder what the real role of the bypass tract
is in atrial fibrillation .
Aim of Work:
Our study aims to search the substrat of atrial fibrillation in patient
with WPW, so predicting the risk of development of atrial fibrillation
post ablation of the accessory pathway.
Methodology
Patients
- 60 patients referred for ablation of their supra-ventricular
tachycardia will be enrolled in the study.
- group A: 30 patients with Wolf-Parkinson-White syndrome.
- group B: 30 patients with atrio-ventricular nodal reentrant
tachycardia (AVNRT).
Inclusion criteria:
- Patient with overt pre-excitation on 12 lead ECG for the patients
with WPW syndrome.
- Symptomatic patients with documented regular short RP
tachycardia.
Exclusion criteria:
- Presence of documented atrial fibrillation on Holter monitoring or
12 lead ECG.
- Presence of one or more risk factor for Afib: age >64y;
Hypertension; Congestive heart failure; Coronary artery disease;
valvular heart disease; Diabetes; left ventricular hypertrophy;
alcohol consumption; induction of Afib during electrophysiological
study.
Methods:
- Full medical history and clinical examination are performed to
exclude risk factors for atrial fibrillation.
- 12 lead ECG is performed.
- Trans-thoracic echocardiography is performed.
Technical aspects
- Assessment of Left Atrium(LA) and Right Atrium(RA) mechanics
and analysis of LA and RA deformation:
Border tracking of the LA and RA will manually traced from the
digitized 2D video clips recorded with good quality ECG signal which
acquired and stored for off-line analysis using XStrain™ software with a
frame rate between 40–80 fps. The endocardial border is automatically
drawn at end diastole using a point-and-click approach. Tracking of LA
and RA wall is obtained from apical 4-chamber view, allowing the
system to analyze longitudinal (LNG) component of LA and RA wall
motion & time-volume curves will be extracted which provided
automatically indexed maximum LAV amd RAV (LAVImax), indexed
minimum LAV and RAV (LAVImin), and LAEF and RAEF.(15,16) We
will measure LNG peak velocities achieved by LA walls and RA walls 1
cm above the mitral annulus and tricuspid annulus respectively in
systole(Sam), early(Eam) and late diastole (Aam). Definition of LA and
RA endocardial border enabled system to calculate regional longitudinal
deformation of the LA and RA walls. Peak systolic strain(εsys) was
measured, LA and RA systolic SR(SRsys) was measured as positive
curve at LV systole (representing reservoir function), early diastole(SRe)
(representing conduit function), atrial diastole (SRa) (representing
contractile function). Image processing algorithm automatically
subdivides the atrial wall into 12 segments distributed in septum& lateral
and posterior LA and RA wall–“roof”). The graphs for each segment
were displayed and averaged to calculate global LA function.(17)
- Assessment of LA and RA electrophysiological characteristics:
Under local anesthesia (Xylocaine), 5 catheters are inserted: Three
quadripolar catheters positioned in the High Right atrium (HRA), Right
Ventricle (RV), Atrio-ventricular Junction (AVJ); One decapolar catheter
in the coronary sinus; One 4 mm tip non-irrigated ablation catheter.
A standard electrophysiological study is performed with its
principal aim the localization of the site of atrial and ventricular insertion
of the accessory pathway in the patients with WPW syndrome; and the
presence of Dual Atrio-Ventricular physiology in patients with AVNRT
as well as the exclusion of concealed accessory pathway.
Measured parameters
This is performed by one operator to avoid personal variability.
The Effective Refractory Period (ERP) and the Relative Refractory
Period (RRP) of both atria will be measured.
Calculation of the inter-atrial conduction delay as well as intraatrial
conduction delay and atrial fragmentation will be taken.
Finally, the latent atrial vulnerability will be calculated.
The relation between Left Atrial and Right Atrial electrophysiological
data and mechanical function will be analyzed.
Conclusion:
Patients with wpw have an intrinsic atrial vulnerability even in the
absence of history of atrial fibrillation, and this atrial vulnerability is
unlikely to be cured by simple ablation of the accessort pathway and thus
they are at risk of developing atrial fibrillation subsequently.
Recommendations:
Patients with WPW need follow up even after successful ablation
of the accessory pathway for risk of development of atrial fibrillation.
There is a relation between elecrophysiological parameters and
speckle tracking echocardiography in detecting atrial vulnerability the
should furtherly studied.