Innovative diagnosis: Accessory pathway localized using strain imaging- EHJ case report.
Figure: Peak longitudinal strain values before (A) and after accessory atrioventricular pathway ablation (B). The regional strain value in the anterior basal wall of the left ventricle was decreased (A, arrow). Improvement in the regional strain at the site of ablation was observed after successful accessory atrioventricular pathway ablation.
JAPAN: In Wolff–Parkinson–White (WPW) syndrome, accessory atrioventricular pathways (AP) result in abnormal pre-excitation around the atrioventricular annuli and produce a dyssynchronous contraction of cardiac chambers. Identification of the AP affects the outcome of catheter ablation. Tanabe et al in an interesting case report have shared their approach using longitudinal 2D-speckle tracking echocardiography (STE) to accurately identify contractile abnormalities associated with the AP, and thus non-invasively estimate the localization of the AP in WPW syndrome.
The patient was a 65-year-old man who had been repeatedly visiting the emergency department because of palpitations. Wolff–Parkinson–White syndrome was suspected from the 12-lead ECG finding obtained at that time, and an antiarrhythmic drug was prescribed; however, it did not improve the symptom. Later, paroxysmal atrial fibrillation (AF) was detected, and the patient was hospitalized for catheter ablation therapy.
WPW syndrome Type B was suspected from lead V1 on ECG, but when 2D-STE was performed a decrease in regional strain was observed in the anterior basal wall of the left ventricle (LV). They identified the earliest site of atrioventricular conduction in sites of 3 and 4 of the coronary sinus catheter under rapid right ventricular pacing (interval, 324 ms). The area was explored with an ablation catheter, and multiple cauterizations were performed at the most probable site.
The conduction disruption of the AP was confirmed, and cauterization of the circumference was additionally performed. Subsequently, pulmonary vein isolation and radiofrequency ablation of the cavo-tricuspid isthmus line were performed successfully.
When 2D-STE was performed on the day after the catheter ablation, improvement in the regional strain at the site of the ablation was observed.(Figure)
Atrioventricular pathways result in abnormal pre-excitation around the atrioventricular annuli and produce a dyssynchronous contraction of cardiac chambers. Non-invasive diagnostic modalities to localize AP with high accuracy before performing catheter ablation can result in a shorter procedure time and fluoroscopy durations.
Strain echocardiography by speckle tracking has been successfully applied to study myocardial deformation and dyssynchrony. Since electrical pre-excitation in WPW causes systolic dyssynchrony, strain by speckle tracking can be used to identify the site of earliest mechanical activation.
"Longitudinal 2D-STE accurately identified contractile abnormalities associated with the AP, allowing us to non-invasively estimate the localization of the AP in WPW syndrome", concluded the authors.
Source: European Heart Journal -case reports: https://doi.org/10.1093/ehjcr/ytab078
