Spot diagnosis of inferior axis and concordant R-pattern predicts left ventricular inflow tract tachycardia: Ablation from the great cardiac vein of an underdiagnosed entity

Abstract

Background: The present literature holds an enormous variation concerning origin and ablation site of idiopathic ventricular arrhythmias (VA), ranging from 2.5 to 15% for the origin within the coronary venous system (CVS). The aim of the study was to detect positive predictive ECG morphology patterns to discriminate VA stemming from the CVS.

Methods: 110 consecutive patients (P) with 111 premature ventricular capture beat (PVC) morphologies undergoing successful ablation for VA were retrospectively analyzed concerning their ECG patterns.

Results: 20/110 P (18%) displayed their VA origin in the CVS with anterior/anterolateral left ventricular inflow tract (LVIT) (epicardial/GCV) in 16 P (14%), anterior/anterolateral LVIT (endo- and epicardial/GCV) in 3 P (3%), and anterior interventricular vein (AIV) 1 P (<1%). ECG morphology of all GCV cases demonstrated an inferior axis and concordant R-pattern in all precordial leads resulting in 100% sensitivity. One VA demonstrating this pattern was ablated outside at the LVOT resulting in 95% specificity for origin in the anterior/anterolateral LVIT. 3/20 P that were ablated in the CVS required additional endocardial ablation from the anterior/anterolateral LVIT resulting in 80% specificity for sole successful ablation in the CVS.

Conclusion: An inferior axis and concordant R-pattern in all precordial leads serve as diagnostic markers for an LVIT origin in the surface ECG and suggest a high primary ablation success via the GCV.

Keywords: Concordant R pattern; Great cardiac vein; Idiopathic VT; LV inflow tract; Spot diagnosis.