B-po03-161 omnipolar technology mapping: derivation and validation against cardiac magnetic resonance-derived maps and endomyocardial biopsy

A novel grid mapping catheter became available and was found to permit quick and accurate mapping during ventricular tachycardia ablation. Omnipolar technology (OT) maximum voltage (Vmax) mapping, a novel grid catheter-based technique allowing high resolution substrate mapping independent of catheter orientation, was recently developed. To assess the feasibility and reliability of OT Vmax maps of the left ventricle (LV), as compared to standard bipolar endocardial maps, and cardiac magnetic resonance (CMR)-derived pixel signal intensity (PSI) maps, among patients undergoing electroanatomical voltage mapping (EVM)-guided endomyocardial biopsy (EMB). We included 5 patients, undergoing LV substrate mapping and EVM-guided EMB at our institution; the LV was mapped with the Advisor HD Grid catheter (Abbott) in stable sinus rhythm. Contrast enhanced-CMR was obtained in each patient before the procedure, and PSI maps were derived from late gadolinium enhancement sequences with the ADAS-VT software (Galgo Medical). Abnormal voltage areas were measured in PSI endocardial (10-50% of wall thickness) maps and compared to low-voltage areas (LVA, defined as peak-to-peak voltage <1.5 mV) measured by standard bipolar endocardial mapping, and OT Vmax endocardial mapping. Continuous variables were checked for normality with the Shapiro-Wilk test, and statistical comparisons were made with the ANOVA or T tests, as appropriate. The main clinical indications for EVM-guided EMB were clinically suspected myocarditis (n=4) or infiltrative cardiomyopathy (n=1). The mean procedural and fluoroscopy times were 130±27 min and 10±6 min, respectively. Endocardial low voltage areas were non-significantly less widespread in OT Vmax than in standard bipolar or PSI maps (OT:13±9 cm2; Bipolar:16±6 cm2; PSI:17±11 cm2; ANOVA p=0.96); furthermore, a numerically higher number of points was obtained with OT Vmax mapping (OT:27699; Bipolar:17787; p=0.19). The diagnostic yield of EMB measured 100%. OT mapping allowed accurate characterization of the LV substrate, and might help limiting false positive low-voltage areas due to poor catheter-tissue contact. Further research is needed to define specific OT Vmax cutoffs for scar.