LAUSR

Outflow tract premature ventricular complexes (PVCs) may be ablated at sites where the local electrogram is early. We describe ablation of PVCs of varying morphology at a cruciate structure extending from the inflection of the great cardiac vein to the junction of the distal RVOT and from the left ventricular (LV) inflow myocardium through the aortic mitral continuity (AMC) to the right coronary sinus of Valsalva centered below LSOV, termed the LV crux. Evaluate a novel target for ablation of PVCs with varied QRS morphologies. A series of 51 patients undergoing ablation for PVCs between 2013–2018 was identified. In all cases, ICE-guided ablation occurred at the center of the LV crux. All patients had high PVC burden >20% (28±8%); EF<50% in 40/51 (78%). QRS morphology of PVCs is summarized in Table 1. 50% had prior ablation attempted at early sites. Mapping and ICE-guided ablation at the LV crux (Figure 1 A-B) revealed early activation with near-field ventricular or fascicular signal in 31 (61%), while others had early sites at extensions of the crux. PVCs were eliminated in 50/51 (98%) with continued suppression at 3-months. EF normalized in all 51. Table 1. ECG charactaeristics ECG characteristics Number of patients (%) Inferior morphology 51/51 (100%) Lead I morphology   Monophasic R 8/51 (16%)   Rs 9/51 (18%)   rS 34/51 (66%) Precordial transition   Positive across precordium 40 (78%)   V2 transition 7 (14%)   V3 transition 4 (8%) Maximum deflection index   <0.55 37 (73%)   >0.55 14 (27%) Figure 1. Mapping and ablation A cruciate interventricular multidimensional crux centered below the LSOV is a site for successful ablation of varied PVC morphologies and should be considered for detailed mapping and ablation, particularly when multiple morphologies are present or prior ablation at early sites is unsuccessful. Ventricular myocardial architecture along with conduction system remnants may be the basis for this phenomenon.