Comparison of standard and Lewis ECG in detection of atrioventricular dissociation in patients with wide QRS tachycardia ☆ Uğur Aksu a, ⁎, Kamuran Kalkan b , Oktay Gülcü c , Selim Topcu c , Serdar Sevimli c , Enbiya Aksakal c , Emrah Ipek b , Mahmut Açıkel c , Ibrahim Halil Tanboğa c a Kars State Hospital, Department of Cardiology, Kars, Turkey b Erzurum Education and Research Hospital, Department of Cardiology, Erzurum, Turkey c Atatürk University, Faculty of Medicine, Department of Cardiology, Erzurum, Turkey abstract article info Article history: Received 28 May 2016 Received in revised form 22 September 2016 Accepted 23 September 2016 Available online 26 September 2016 Background: The atrioventricular (AV) dissociation, which is frequently used in differential diagnosis of wide QRS complex tachycardia (WQCT), is the most specific finding of ventricular tachycardia (VT) with lower sensitivity. Herein, we aimed to show the importance of Lewis lead ECG records to detect ‘visible p waves’ during WQCT. Method: A total of 21 consecutive patients who underwent electrophysiologic study (EPS) were included in the study. During EPS, by using a quadripolar diagnostic catheter directed to the right ventricular apex, a fixed stim- ulus was given and the ventriculoatrial (VA) Wenkebach point was found, and a VT was simulated by a RV apical stimulus at 300 ms. The standard and Lewis lead ECG records were taken during this procedure. Result: We detected ‘visible p waves’ in 7 (33.3%) and 14 (66.7%) patients in the standard and Lewis lead ECG groups, respectively. In terms of the ‘visible p waves’, there was a statistically significant difference between groups (p = 0.022). The sensitivity of standard and Lewis lead ECG in determination of the visible p waves was 33.3% and 66.7%, respectively. Conclusion: The Lewis lead ECG can be more informative about AV dissociation than the standard 12 lead ECG. As a result, we could suggest the assessment of the Lewis lead ECG recording in addition to the standard 12 lead ECG in differential diagnosis of VT in patients with WQCT. © 2016 Elsevier Ireland Ltd. All rights reserved. Keywords: Electrophysiology Ventricular tachycardia Lewis ECG Electrocardiography 1. Introduction ECG plays a basic role in differential diagnosis of ventricular tachy- cardia (VT) during wide QRS complex tachycardia (WQCT), however, over time newer and more rapid alternative diagnostic tools have been developed because 12 lead ECG is mostly insufficient [1–3]. The AV dissociation, which is used in differential diagnosis of WQCT, is one of the most specific findings of VT but owing to the low amplitude of the p wave, could only be recognized in 30% of the cases. Due to this rea- son, the absence of AV dissociation does not exclude VT. Methods in- creasing the visibility of AV dissociation in ECG are useful for differential diagnosis of VT. The Lewis lead configuration is one of these methods with increased p wave visibility and has been reported in a few case reports for usefulness in diagnosis of VT, however, there is no study showing the role of Lewis lead ECG in detection of atrial ac- tivity (AV dissociation) in patients with WQCT [4–10]. The aim of this study is to evaluate the efficacy of Lewis lead config- uration to detect AV dissociation and its ability to aid current diagnostic algorithms in patients presenting with WQCT as a result of right ventric- ular apical stimulation. 2. Materials and methods 2.1. Study design This prospective study was approved by the institutional review board and complies with the Declaration of Helsinki. The informed consents were taken from all patients. A total of 21 out of 36 patients who were referred to our tertiary cardiac center for electro- physiologic study (EPS) between October 2014 and December 2014 were eligible for and included in the study. 2.2. Inclusion and exclusion criteria The patients presenting with palpitations, syncope and/or the ones with documented and clinically important cardiac arrhythmias (tachycardia with drug-resistance, tachycar- dia with drug intolerance, and tachycardia-induced cardiomyopathy) who were candi- dates for EPS according to the current guidelines, were included in the study. Hemodynamic instability, atrial fibrillation and an intact ventriculoatrial (VA) conduction at 300 ms stimulation during EPS were excluded from the study. Prior to the procedure, information concerning the clinical data, currently used drugs, atherosclerotic risk factors, presence of coronary artery disease, echocardiography, 12- International Journal of Cardiology 225 (2016) 4–8 ☆ Preliminary results of this study were presented at the 11th International Congress of Update in Cardiology and Cardiovascular Surgery in Antalya (TR), 2015. ⁎ Corresponding author at: Kars State Hospital, Department of Cardiology, Kars, Turkey. E-mail address: aksuuu001@msn.com (U. Aksu). http://dx.doi.org/10.1016/j.ijcard.2016.09.087 0167-5273/© 2016 Elsevier Ireland Ltd. All rights reserved. Contents lists available at ScienceDirect International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard