Noninvasive localization of cardiac arrhythmias using electromechanical wave imaging

Abstract

Cardiac arrhythmias are a major cause of morbidity and mortality worldwide. The 12-lead electrocardiogram (ECG) is the current noninvasive clinical tool used to diagnose and localize cardiac arrhythmias. However, it has limited accuracy and is subject to operator bias. Here, we present electromechanical wave imaging (EWI), a high–frame rate ultrasound technique that can noninvasively map with high accuracy the electromechanical activation of atrial and ventricular arrhythmias in adult patients. This study evaluates the accuracy of EWI for localization of various arrhythmias in all four chambers of the heart before catheter ablation. Fifty-five patients with an accessory pathway (AP) with Wolff-Parkinson-White (WPW) syndrome, premature ventricular complexes (PVCs), atrial tachycardia (AT), or atrial flutter (AFL) underwent transthoracic EWI and 12-lead ECG. Three-dimensional (3D) rendered EWI isochrones and 12-lead ECG predictions by six electrophysiologists were applied to a standardized segmented cardiac model and subsequently compared to the region of successful ablation on 3D electroanatomical maps generated by invasive catheter mapping. There was significant interobserver variability among 12-lead ECG reads by expert electrophysiologists. EWI correctly predicted 96% of arrhythmia locations as compared with 71% for 12-lead ECG analyses [unadjusted for arrhythmia type: odds ratio (OR), 11.8; 95% confidence interval (CI), 2.2 to 63.2; P = 0.004; adjusted for arrhythmia type: OR, 12.1; 95% CI, 2.3 to 63.2; P = 0.003]. This double-blinded clinical study demonstrates that EWI can localize atrial and ventricular arrhythmias including WPW, PVC, AT, and AFL. EWI when used with ECG may allow for improved treatment for patients with arrhythmias.

Cardiac Resynchronization Therapy Response Assessment with Electromechanical Activation Mapping within 24 Hours of Device Implantation: A Pilot Study

“…Its most recent prototype version programmed directly on the research ultrasound scanner is able to acquire, process, and generate 3D-rendered isochrones in <10 min. 20 Machine learning approaches have also recently been developed toward an automated and less operator dependent isochrone generation process, decreasing the time required to generate the activation maps from the current standard 90 min to <5 min per patient. 30 Hence, the operating electrophysiologists could rely on critical information provided by the 3Drendered maps at the time of point of care to optimize lead placement and/or pacing conditions appropriately to conceivably further improve resynchrony, increase %RM LV values, and thus potentially ensure better response rates.…”

“…This multi-2D sampling effect was recently investigated in LV-paced canines. 20 Future studies using 3D volumetric ultrasound could avoid this undersampling issue by mapping the entire cardiac electromechanical activity in a single heartbeat. Our group has already shown feasibility in a proof-of-concept study.…”

“…Motion is estimated in one dimension with crosscorrelation tracking on the radiofrequency data, 18 and infinitesimal incremental/interframe axial strain, namely, electromechanical strain (on the order of 0.01%) is derived throughout systole using a least squares estimator. 19 The activation timings, defined as the positive-to-negative strain zero-crossing locations (change from relaxation to contraction), are manually selected on the incremental axial strain curves of the myocardial points after QRS onset 10,20 and later displayed on color-coded two-dimensional (2D) activation maps (milliseconds), with red denoting early activation and blue late (Supplemental Figures 1B, 1C and Supplemental Figures 2.1B, 2.1C, 2.2B and 2.2C). Once all four multi-2D isochrones are created and coregistered, a linear interpolation of the activation time points is performed circumferentially to subsequently generate the 3D-rendered activation maps according to the algorithm in Nauleau et al 16 As a reference, a voxel on the resulting map has an approximate size of 1.7 Â 1.7 Â 0.06 mm (in the x elevational, y lateral, and z axial directions, respectively).…”

“…For further details on our EWI acquisition sequence and processing pipeline, see our previous publications. 14,17,20…”

Simultaneous widefield voltage and interferometric dye-free optical mapping quantifies electromechanical waves in human iPSC-cardiomyocytes

“…Such knowledge can also improve in silico electromechanical models, which have been developed over the years(Nash and Panfilov 2004, Trayanova, Constantino et al 2011, Trayanova and Rice 2011, Wang, Santiago et al 2021) but not extensively validated. Dissecting such wave interactions can inform translational imaging of electromechanical waves in the heart for noninvasive arrhythmia mapping in the clinic(Provost, Lee et al 2011, Christoph, Chebbok et al 2018, Grubb, Melki et al 2020).…”