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Using the Initial Vector from Surface Electrocardiogram to Distinguish the Site of Outflow Tract Tachycardia
Author(s) -
YANG YANFEI,
SAENZ LUIS C.,
VAROSY PAUL D.,
BADHWAR NITISH,
JUSTIN H. TAN,
KILICASLAN FETHI,
KEUNG EDMUND C.,
NATALE ANDREA,
MARROUCHE NASSIR F.,
SCHEINMAN MELVIN M.
Publication year - 2007
Publication title -
pacing and clinical electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.686
H-Index - 101
eISSN - 1540-8159
pISSN - 0147-8389
DOI - 10.1111/j.1540-8159.2007.00777.x
Subject(s) - medicine , ventricular outflow tract , nadir , cardiology , qrs complex , predictive value , tachycardia , receiver operating characteristic , ventricular tachycardia , sinus tachycardia , ablation , electrocardiography , positive predicative value , radiofrequency ablation , satellite , engineering , aerospace engineering
Background:The purpose of this study is to determine whether initial vector force might best distinguish tachycardias arising from the right ventricular (RV) outflow tract (OT) versus aortic sinus cusps (ASCs).Methods:Among 45 patients with OT tachycardia, we measured the time from the earliest QRS onset in any lead to local onset and to the first QRS peak/nadir in each surface leads during VT. We compared the earliest phase differences among patients with foci in RVOT (n = 32) and in ASCs (n = 13) (determined by ablation), using unpaired t‐tests. We determined the optimum cut‐points by analyzing the receiver–operator characteristics curves, and derived an algorithm to discriminate ASC from RVOT foci.Results:Compared with an RVOT focus, origin in the ASC was associated with lower likelihood that the earliest lead of QRS activation was V2 (4/13 [12%] vs 29/32 [88%], P = 0.0001), later initial peak/nadir in III (110 ± 19 vs 93 ± 16 ms, P = 0.0026) and V2 (75 ± 26 vs 42 ± 19 ms, P < 0.0001). After determining the optimum cut‐points for each, we found that the presence of any one of these findings discriminated well between RVOT and ASC foci (sensitivity 92%, specificity 88%, positive predictive value 75%, and negative predictive value 97%). The sensitivity and specificity using standard ECG criteria were inferior to the vector approach.Conclusions:The ECG phase differences during VT can distinguish the origin of OT‐VT. Earliest onset or first peak/nadir in V2 and early initial peak/nadir in the inferior leads suggest a RVOT focus.