Catheter Ablation -> Ventricular Arrhythmias -> Mapping & Imaging D-PO06 - Poster Session VI (ID 26) Poster

D-PO06-097 - How Much Mapping Is Required To Characterize The Ventricular Tachycardia Substrate In Ischemic Cardiomyopathy? (ID 1362)


Background: The number of points needed to delineate substrate on electroanatomical maps (EAM) for ventricular tachycardia (VT) is unclear.
Objective: To determine the effect of point density on VT substrate EAM in ischemic cardiomyopathy (ICM).
Methods: 12 ICM patients had detailed multipolar LV EAM (825±399 points /map). From original EAM, points within the bipolar low voltage area (LVA), <1.5mV, were deleted randomly and blindly to create new maps with 50%, 25%, and 10% of original points. We assessed 1) % of LVA, 2) the localization of critical site for VT based on entrainment or pace mapping, and 3) prevalence of abnormal electrograms-EGs (% abnormal EGs points /all points) in each of the 48 maps.
Results: The point density within LVA was 7.4±3.7/cm2 in original map, 4.3±2.2/cm2 in 50%, 2.6±1.3/cm2 in 25%, and 1.3±0.6/cm2 in 10% maps. The LVA was 52.2±10.7% in original map, 47.1±10.8% in 50%, 42.0±11.0% in 25% and 35.6±10.3% in 10% maps, and decreased around edge of LVA as points deleted (p<0.01). The critical site for the VT was always located within LVA in every map for all patients (Figure) regardless of the points. The prevalence of abnormal EGs was not significantly different between each map (7.2%±4.1% in original map, 7.3%±4.0% in 50%, 7.2%±4.4% in 25% and 7.6%±5.3% in 10% map)
Conclusion: In patients with ICM and VT, although the border of LVA is reduced, critical area for VT circuitry can typically still be identified within the EAM substrate defined with fewer points as long as EAM is sampled with density of >1point per cm2