Clinical Electrophysiology -> Ventricular Arrhythmias -> Mapping & Imaging D-PO01 - Featured Poster Session (ID 11) Poster

D-PO01-006 - Perfusion Defects Assessed With Rubidium-82 Positron Emission Tomography(82Rb-PET): Correlation To Vt Substrate And Successful Ablation Sites (ID 878)

Abstract

Background: A detailed correlation between 82Rb-PET perfusion defects and ischemic VT substrate has not been previously performed.
Objective: To compare 82Rb PET perfusion defects to high-resolution electroanatomic maps (EAM) in ischemic VT patients.
Methods: Left ventricular (LV) 3D reconstructions were created from 82Rb-PET perfusion images in ischemic patients undergoing VT ablation. PET perfusion defects were defined as severe (<50% uptake) or moderate (50-80% uptake) based on the maximum uptake value in 17-segment analysis. LV 3D reconstructions were co-registered with the corresponding high-resolution 3D EAM maps.
Results: In 31 patients, severe PET defects were larger than EAM scar (<0.5mV) with 40.5±30.8 cm2 vs 21.9±34.3 cm2 (p<0.05). Moderate and severe PET defects (<80% uptake) were larger than abnormal EAM area (<1.5mV) with 107.52±43.67 cm2 vs 74.13±55.50 cm2 (p<0.01). Overlap between PET <50% and EAM <0.5mV was 54.1%, while PET <80% scar and EAM <1.5mV was 74.4%. VT channel/exit sites (n=35 in 31 pts) were in an area of <80% 82Rb perfusion uptake in 89%. Of those, 26% and 63% co-localized to severe or moderate perfusion defects. 11% of VT channel/exit sites localized to areas of normal perfusion (>80%) but were all within 12±7mm distance to areas of abnormal tracer uptake. Rapid transition areas (RTA; >40% uptake change in <15mm) were seen in 45% of patients with an average width of 12.5±1.8 mm. They co-localized with the VT channel/exit site in 57% of patients. ROC curve analysis for 82Rb-PET uptake to predict EAM scar with voltage segments <0.5 mV showed AUC of 0.75 (95% CI: 0.6-0.9, p=0.01). Kaplan-Meier survival curves showed a non-significant increase in 7-year mortality for above median <80% PET uptake (25% vs 70%, p=0.29) and moderate PET defect area (30% vs 70%, p=0.43).
Conclusion: Color-coded, incremental 3D 82Rb-PET perfusion maps can be successfully registered with clinical mapping systems. Perfusion maps predict successful ablation sites in ~90% of VT and can identify intra-VT substrate heterogeneities such as RTA associated with VT. Nearly half of the myocardium with severe perfusion defect is able to generate >0.5mV bipolar voltage suggesting significant surviving electrically active myocardial cells within this region.
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