Head- To-Head Comparison of T1 Mapping and Electroanatomical Voltage Mapping in Patients with Ventricular Arrhythmias

Abstract

Objective: To assess the relation between left ventricular (LV) endocardial voltage obtained by electroanatomical voltage mapping (EAVM) and extracellular volume (ECV) obtained by T1-mapping. Background: EAVM has been compared with late gadolinium enhancement cardiovascular magnetic resonance (LGE-CMR), which cannot delineate diffuse fibrosis. T1-mapping CMR overcomes the limitations of LGE-CMR, but has not been directly compared against EAVM. Methods: The study investigated patients who underwent endocardial EAVM for ventricular arrhythmias (CARTO 3, Biosense Webster, Diamond Bar, USA) together with pre-procedural contrast-enhanced T1-mapping (Ingenia 3T, Philips Healthcare, Best, the Netherlands). After image integration, EAVM data-points were projected onto LGE-CMR and ECV-encoded images. Average values of unipolar voltage (UV), bipolar voltage (BV), LGE-transmurality and ECV were merged from corresponding cardiac segments (6 per slice) and pooled for analysis.Results: The analysis included data of 628 segments from 18 patients (age: 57{plus minus}13 years, female gender: 17%, LV ejection fraction: 48{plus minus}14%, non-ischemic/ischemic cardiomyopathy/controls: 8/6/4 patients). Based on the 95th and 5th percentile values obtained from the controls, ECV >33%, BV <2.9mV and UV <6.7mV were considered abnormal. There was a significant inverse association between voltage and ECV, but only in segments with abnormal ECV. Increased ECV could predict abnormal BV and UV with acceptable accuracy (AUC: 0.78 [CI 0.74 - 0.83] and 0.84 [CI 0.79 - 0.88]). Conclusion: This study found a significant inverse relationship between LV endocardial voltage and ECV. Real time integration of T1 mapping may guide catheter mapping and may allow identification of areas of diffuse fibrosis potentially related to ventricular arrhythmias

Keywords: ECV, T1 mapping, fibrosis, voltage, image integration