Validation of Activation Recovery Interval in Structurally Normal Human Ventricles by Optical Mapping

Background: A large Dispersion of Repolarization (DoR) is associated with an increased arrhythmogenic risk. This can be measured clinically by calculating the Activation Recovery Interval (ARI) to estimate Action Potential Duration (APD). However, the ability of ARI to accurately predict APD dispersion in patients with repolarization abnormality has not been determined. Objective: Compare ARI calculated from patients with optical mapping of human hearts to establish the validity of ARI as a surrogate for APD. Methods: Optical mapping (OM) was performed on the left ventricles of 4 explanted human hearts. APD and repolarization times were measured endo- and epicardially on the anterior of the LV. Electroanatomic mapping was performed with CARTO over the entire endo- and epicardial surfaces of 3 patients. Activation and repolarization were calculated, dispersion of ARI was measured. Results: APD and ARI were consistent between mapping methods over most of the sub-regions studied. Epicardium ARI dispersion was consistently higher than that of the endocardium in both OM and CARTO datasets. Conclusion: APD distribution, and consequently DoR, agree between mapping methods. Measuring DoR by ARI accurately assesses the underlying repolarization abnormalities in patients.