Novel Imaging Method Locates Cardiac Arrhythmias, Finds Study
Cardiac arrhythmias are a cause of morbidity and mortality, often necessitating invasive catheter ablation for curative treatment. Diagnosis and localization of cardiac arrhythmias are critical for clinical decision making and treatment planning. In a study, researchers have used noninvasive ultrasound called electromechanical wave imaging (EWI) to generate maps of the heart and to identify the sites of arrhythmias suggesting that the addition of this imaging method to clinical workflows could help improve decision-making and treatment planning. The research has been published in the journal Science Translational Medicine on March 25, 2020.
Electrocardiogram (ECG) algorithms have been proposed to aid in the localization of arrhythmias but have varying accuracy, and inter-observer variability is common. EWI is a high frame rate ultrasound technique that can noninvasively map with high accuracy the electromechanical activation of atrial and ventricular arrhythmias in adult patients. There has been some controversy regarding the accuracy of the inverse solution in ECGI (electrocardiogram imaging). Exploration of other noninvasive mapping approaches, such as EWI, is therefore warranted. Dr Christopher S. Grubb and his team conducted a study to evaluate the accuracy of EWI for localization of various arrhythmias in all four chambers of the heart before catheter ablation.
Researchers included a total of fifty-five patients with an accessory pathway (AP) with Wolff-Parkinson-White syndrome (WPW), premature ventricular complexes (PVC), atrial tachycardia (AT), or atrial flutter (AFL) underwent transthoracic EWI and 12-lead ECG. They compared the diagnostic accuracy of both atrial and ventricular EWI isochrones (multi-2D or 3D-rendered) with 12-lead ECG-based localization by expert electrophysiologists and finally to the gold standard of 3D electroanatomical maps performed with invasive catheter mapping and eventual successful site of ablation.
Key findings of the study were:
- Upon evaluation, the researchers found significant inter-observer variability amongst 12-lead ECG reads by expert electrophysiologists.
- They also found that 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; adjusted for arrhythmia type: OR: 12.1].
The authors concluded, "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."
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