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Arrhythmia localization prior to catheter ablation is critical for clinical decision making and treatment planning. The current standard lies in 12-lead electrocardiogram (ECG) interpretation, but this method is non-specific and anatomically limited. Accurate localization requires intracardiac catheter mapping prior to ablation. Electromechanical Wave Imaging (EWI) is a high frame-rate ultrasound modality capable of non-invasively mapping the electromechanical activation in all cardiac chambers in vivo. In this study, we evaluate 3D-rendered EWI as a technique for consistently localizing the accessory pathway (AP) in Wolff-Parkinson-White (WPW) pediatric patients. A 2000 Hz EWI diverging sequence was used to transthoracically image 13 patients with evidence of ECG pre-excitation, immediately prior to catheter ablation and after successful ablation whenever possible. 3D-rendered activation maps were generated by co-registering and interpolating the 4 resulting multi-2D isochrones. A blinded electrophysiologist predicted the AP location on 12-lead ECG prior to ablation. Double-blinded EWI isochrones and clinician assessments were compared to the successful ablation site as confirmed by intracardiac mapping using a segmented template of the heart with 19 ventricular regions. 3D-rendered EWI was shown capable of consistently localizing AP in all the WPW cases. Clinical ECG interpretation correctly predicted the origin with an accuracy of 53.8%, respectively 84.6% when considering predictions in immediately adjacent segments correct. Our method was also capable of assessing the difference in activation pattern from before to after successful ablation on the same patient. These findings indicate that EWI could inform current diagnosis and expedite treatment planning of WPW ablation procedures.

Objectives: This study sought to demonstrate the feasibility of electromechanical wave imaging (EWI) for localization of accessory pathways (AP) prior to catheter ablation in a pediatric population., Background: Prediction of AP locations in patients with Wolff-Parkinson-White syndrome is currently based on analysis of 12-lead electrocardiography (ECG). In the pediatric population, specific algorithms have been developed to aid in localization, but these can be unreliable. EWI is a noninvasive imaging modality relying on a high frame rate ultrasound sequence capable of visualizing cardiac electromechanical activation., Methods: Pediatric patients with ventricular pre-excitation presenting for catheter ablation were imaged with EWI immediately prior to the start of the procedure. Two clinical pediatric electrophysiologists predicted the location of the AP based on ECG. Both EWI and ECG predictions were blinded to the results of catheter ablation. EWI and ECG localizations were subsequently compared with the site of successful ablation., Results: Fifteen patients were imaged with EWI. One patient was excluded for poor echocardiographic windows and the inability to image the entire ventricular myocardium. EWI correctly predicted the location of the AP in all 14 patients. ECG analysis correctly predicted 11 of 14 (78.6%) of the AP locations., Conclusions: EWI was shown to be capable of consistently localizing accessory pathways. EWI predicted the site of successful ablation more frequently than analysis of 12-lead ECG. EWI isochrones also provide anatomical visualization of ventricular pre-excitation. These findings suggest that EWI can predict AP locations, and EWI may have the potential to better inform clinical electrophysiologists prior to catheter ablation procedures., (Copyright © 2019 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Risk stratification of patients with Wolff-Parkinson-White syndrome for sudden death is a complex process, particularly in understanding the utility of the repeat exercise stress test. We report a case of an 18-year-old patient who was found to have a high-risk pathway by both invasive and exercise stress testing after an initial exercise stress test showing beat-to-beat loss of pre-excitation.

Background: First-line therapy for children with attention-deficit-hyperactivity disorder (ADHD) is stimulant medication, which may have potential cardiovascular side-effects. In patients with supraventricular tachycardia or Wolf-Parkinson-White syndrome (WPW), therapy for ADHD could become challenging. The purpose of the present study was to review the authors' experience of performing electrophysiologic study (EPS) with or without ablation to determine how it affected ADHD therapy., Methods: Retrospective chart review of patients who underwent EPS between 2002 and 2009 was carried out. All patients under 21 years of age who had prior diagnosis of ADHD were included., Results: Twenty patients met the inclusion criteria. The mean age was 12.1 ± 2.7 years (range: 5.6-16.8 years). The patients were diagnosed with ADHD on average 3.9 ± 2.7 years (range: 6 months-9 years) prior to the EPS. All patients had a structurally normal heart. Sixteen patients had cardiac symptoms. Seventeen patients underwent ablation of the arrhythmia substrate (16/17, 94% successful). Three patients with asymptomatic WPW were at low risk for life-threatening arrhythmias and did not have ablation. After the EPS, two patients had increased doses of their ADHD medications, and two patients whose health-care providers stopped the stimulant medication prior to EPS because of recurrent tachycardia were restarted on medications. All other patients on ADHD medications continued therapy., Conclusions: EPS for risk stratification and ablation of arrhythmia substrate is safe and effective, allowing more liberal therapy in patients with ADHD and supraventricular tachycardia or WPW., (© 2011 The Authors. Pediatrics International © 2011 Japan Pediatric Society.)

A 16-year-old female patient with Wolff-Parkinson-White syndrome and supraventricular tachycardia underwent radiofrequency (RF) catheter ablation of an accessory pathway in the left lateral area. During RF ablation she developed reversible ST segment elevation secondary to coronary artery spasm. Coronary angiography demonstrated the ablation catheter in close proximity to the circumflex coronary artery, with no evidence of coronary artery injury. Subsequently, conduction by way of the accessory pathway was successfully eliminated with cryoablation with no further coronary spasm or injury.