Innovative diagnosis: Accessory pathway localized using strain imaging- EHJ case report.
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.
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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