Syed Zahid Jamal, Kashaf Aqeel Zaidi, Sajid Ali Sheikh, Ammar Ahmed, Ghazala Irfan, Faisal Qadir


Background: This study was conducted to establish the accuracy of R/S ratios in localizing accessory pathways in Wolff Parkinson White Syndrome on surface ECGs. Methods: This was a retrospective cross-sectional study from January 2002 till December 2016 conducted at National Institute of Cardiovascular diseases in Karachi, Pakistan. The sample included 157 patients with manifesting Wolff Parkinson White (WPW) Syndrome on a 12-lead surface ECG. As per the inclusion criteria, patients who had persistent or intermittent pre-excitation on surface ECG and had undergone electrophysiological study (EP) were included in the sample. Individuals with both successful and unsuccessful ablation procedures were included. Results: The sample consisted of 62.4% males (n=98) and 37.6% females (n=59) with mean age being 35.36±12.44. Accessory pathways (APs) were identified on the left side in majority of the patients with 54.1% (n=85) while right sided pathways were seen in 42.1% (n=66). Moreover, the most common accessory pathway amongst the males was Left Anterior (LA) and Left Lateral (LL) with a percentage of 48%, followed by Right Posteroseptal (RPS) at 20.4%. As opposed to this, the most common pathways amongst the females turned out to be RPS at 33.9% followed by LL and LA at 32.2%. Furthermore, the test using ratios were most effective in identifying left sided APs with sensitivity 74.1% and was least sensitive in identifying right sided pathways (sensitivity=40.7%). However, it was highly specific in locating right sided pathways with specificity of 94.6% as opposed to 83.3% in the left side. Furthermore, mid-septum regions had a sensitivity and specificity of 66.7% and 69.6% respectively. Conclusion: This establishes the effectiveness of R/S ratios in determining the location of accessory pathway based on the surface ECG prior to the ablation procedure. Since the younger population is affected more commonly, prolonged exposure to ionizing radiation can cause long term complications therefore, by this means, the duration of exposure can be reduced.

Keywords: Wolff Parkinson White Syndrome; accessory pathways; surface ECG; electrophysiology ablation

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Gollob MH, Green MS, Tang AS, Gollob T, Karibe A, Ali Hassan AS, et al. Identification of a gene responsible for familial wolff–parkinson–white syndrome. N Engl J Med 2001;344(24):1823–31.

Keating L, Morris FP, Brady WJ. Electrocardiographic features of Wolff-Parkinson-White syndrome. Emerg Med J 2003;20(5):491–3.

Wolff L, Parkinson J, White PD. Bundle branch block with short P-R interval in healthy young people prone to paroxysmal tachycardia. Am Heart J 1930;5:685–704.

Schamroth L. An introduction to electrocardiography. 7th ed. Oxford: Blackwell Scientific; 1990.

Sethi KK, Dhall A, Chadha DS, Garg S, Malani SK, Mathew OP. WPW and preexcitation syndromes. J Assoc Physicians India 2007;55(Suppl):10–5.

Hummel JD, Kalbfleisch SJ, Dillon JD. Pocket guide for cardiac electrophysiology. 1st ed. Philadelphia: WB Saunders Company; 2000.

Calkins H. Radiofrequency catheter ablation of supraventricular arrhythmias. Heart 2001;85(5):594–600.

Wren C, Vogel M, Lord S, Abrams D, Bourke J, Rees P, et al. Accuracy of algorithms to predict accessory pathway location in children with Wolff- Parkinson-White syndrome. Heart 2012;98(3):202–6.

Arruda MS, McClelland JH, Wang X, Beckman KJ, Widman LE, Gonzalez MD, et al. Development and validation of an ECG algorithm for identifying accessory pathway ablation site in Wolff- Parkinson White syndrome. J Cardiovasc Electrophysiol 1998;9(1):2–12.

Fitzpatrick AP, Gonzales RP, Lesh MD, Modin GW, Lee RJ, Scheinman MM. New algorithm for the localization of accessory atrioventricular connections using a baseline electrocardiogram. J Am Coll Cardiol 1994;23(1):107–16.

Taguchi N, Yoshida N, Inden Y, Yamamoto T, Miyata S, Fujita M, et al. A simple algorithm for localizing accessory pathways in patients with Wolff-Parkinson-White syndrome using only the R/S ratio. Journal of Arrhythmia, 2014;30(6):439–43.

Al-Khatib SM, Pritchett EL. Clinical features of Wolff-Parkinson-White syndrome. Am Heart J 1999;138(3 Pt 1):403–13.

Fox DJ, Klein GJ, Skanes AC, Gula LJ, Yee R, Krahn AD. How to identify the location of an accessory pathway by the 12-lead ECG. Heart Rhythm 2008;5(12):1763–6.

Cain N, Irving C, Webber S, Beerman L, Arora G. Natural history of Wolff-Parkinson-White syndrome diagnosed in childhood. Am J Cardiol 2013;112(7):961–5.

Dar M, Sheikh SH, Abid AR, Mallick NH. Localization of Accessory Pathways according to AP Fitzpatrick ECG Criteria in patients with Wolff-Parkinson-White Syndrome in our population. Pak Heart J 2012;41(3-4):21–7.

Saidullah S, Shah B, Ullah H, Aslam Z, Khan MA. Localization of accessory pathway in patients with Wolff-Parkinson-White Syndrome from surface ECG using Arruda Algorithm. J Ayub Med Coll Abbottabad 2016;28(3):441–4.

Shafquat A, Imdad A, Khalid S, Jamal S. Cardiac Electrophysiology Studies and Ablations for Treatment of Supraventricular Arrhythmias--An Initial Experience from Karachi. J Pak Med Assoc 2011;61(2):173–5.

Colavita PG, Packer DL, Pressley JC, Ellenbogen KA, O'Callaghan WG, Gilbert MR, et al. Frequency, diagnosis and clinical characteristics of patients with multiple accessory atrioventricular pathways. Am J Cardiol 1987;59(6):601–6.

Calkins H, Prystowsky E, Berger RD, Saul JP, Klein LS, Liem LB, et al. Recurrence of conduction following radiofrequency catheter ablation procedures: relationship to ablation target and electrode temperature. The Atakr Multicenter Investigators group. J Cardiovasc Electrophysiol 1996;7(8):704–12.

Calkins H, Yong P, Miller JM, Olshansky B, Carlson M, Saul JP, et al. Catheter ablation of accessory pathways, atrioventricular nodal reentrant tachycardia, and the atrioventricular junction: final results of a prospective, multicenter clinical trial. The Atakr Multicenter Investigators Group. Circulation 1999;99(2):262–70.

Calkins H, Sousa J, El-Atassi R, Rosenheck S, de Buitleir M, Kou WH, et al. Diagnosis and cure of the Wolff-Parkinson-White syndrome or paroxysmal supraventricular tachycardias during a single electrophysiology test. N Engl J Med 1991;324(23):1612–18.

Teixeira CM, Pereira TA, Lebreiro AM. Carvalho SA. Accuracy of the Electrocardiogram in Localizing the Accessory Pathway in Patients with Wolff-Parkinson-White Pattern. Arq Bras Cardiol 2016;107(4):331–8.

Moraes L, Maciel W, Carvalho H, Oliveira Jr NA, Siqueira LR, Tavares CM. A acurácia dos algoritmos eletrocardiográficos na localização das vias anômalas na síndrome de Wolff-Parkinson-White. Rev SOCERJ 2006;19(4):156–64.


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