LOCALIZATION OF ACCESSORY PATHWAYS ACCORDING TO AP FITZPATRICK ECG CRITERIA IN PATENTS WITH WOLFF-PARKINSON-WHITE SYNDROME IN OUR POPULATION

Abstract

Objectives: The objective of this prospective study was to localize the accessory pathways (AP) in patients
with Wolff Parkinson White syndrome (WPW) using algorithm laid down by AP Fitzpatrick, in our
population.
Materials and Methods: 500 consecutive patients with the most pre-excited 12 lead ECG in sinus rhythm
visiting emergency department were analyzed. Delta wave frontal plane vector, polarity in V1, height in leads
I, II and Ill and sum of delta waves polarities in II, lII and aVF. R wave size in leads I, II, Ill, V1; R/S ratio in
leads I, aVL, V1; S wave size in V1 and QRS axis and duration; QRS horizontal plane transition zone were
the main EGG variables used to localize the accessory pathway. The most discriminative characteristics were
combined to form the following steps. Step 1, location of the transition lead (R and S waves are equiphasic) in
the chest leads and R>S wave by > or < 1mV, this divides the pathways into right and left sided. Step 2, sum
of delta waves polarities in leads II, Ill and aVF, this divides the pathways into Septal or lateral locations.
Results: Among 500 patients, 409(81.8%) patients had WPW syndrome while 91(18.2%) patients had WPW
pattern. Mean age of study population was 34.23±12.5 years. There were 327(65.4%) males and 173(34.6%)
females with a male to female ratio of 3:1. Three hundred (60%) patients had right sided accessory pathways
while 190(38%) had left sided AP. Among right sided AP Right posteroseptal pathway was the most common
location 87(28.8%) comprising (17.7%) of total population. Left antero-lateral pathway was the most
common location not only among left sided pathways 95(50%) but also in total study population (19.4%).
Conclusion: The AP Fitzpatrick ECG criteria for localization of the accessory pathways on surface ECG is an
excellent non invasive method for determination of the site of accessory pathway with very high sensitivity,
specificity and predictive accuracy. It is an excellent tool before planning invasive electrophysiological study
in WPW syndrome.