Intra-cardiac ultrasound guided approach for catheter ablation of typical right free wall accessory pathways

Zero-Fluoroscopy Catheter Ablation of Supraventricular Tachycardias in the Pediatric Population

Catheter ablation (CA) of supraventricular tachycardias (SVTs) is conventionally performed with the aid of X-ray fluoroscopy. Usage of a three-dimensional (3D) electro-anatomical mapping (EAM) system and intracardiac echocardiography (ICE) enables zero-fluoroscopy ablation, eliminating the harmful effects of radiation. We retrospectively analyzed the feasibility, effectiveness and safety of zero-fluoroscopy radiofrequency and cryoablation of various types of SVTs in pediatric patients. Overall, in 171 consecutive patients (12.5 ± 3.9 years), 175 SVTs were diagnosed and 201 procedures were performed. The procedural success rate was 98% (193/197), or more precisely, 100% (86/86) for AVNRT, 95.8% (91/95) for AVRT, 94.1% (16/17) for AT and 100% (2/2) for AFL. No complications were recorded. Follow-up was complete in 100% (171/171) of patients. During the mean follow-up period of 488.4 ± 409.5 days, 98.2% of patients were arrhythmia-free with long-term success rates of 98.7% (78/79), 97.5% (78/80), 100% (13/13) and 100% (2/2) for AVNRT, AVRT, AT and AFL, respectively. Zero-fluoroscopy CA of various types of SVTs in the pediatric population is a feasible, effective and safe treatment option.

Medical instrument detection in ultrasound: a review

Medical instrument detection is essential for computer-assisted interventions, since it facilitates clinicians to find instruments efficiently with a better interpretation, thereby improving clinical outcomes. This article reviews image-based medical instrument detection methods for ultrasound-guided (US-guided) operations. Literature is selected based on an exhaustive search in different sources, including Google Scholar, PubMed, and Scopus. We first discuss the key clinical applications of medical instrument detection in the US, including delivering regional anesthesia, biopsy taking, prostate brachytherapy, and catheterization. Then, we present a comprehensive review of instrument detection methodologies, including non-machine-learning and machine-learning methods. The conventional non-machine-learning methods were extensively studied before the era of machine learning methods. The principal issues and potential research directions for future studies are summarized for the computer-assisted intervention community. In conclusion, although promising results have been obtained by the current (non-) machine learning methods for different clinical applications, thorough clinical validations are still required.

Conventional fluoroscopy-guided versus zero-fluoroscopy catheter ablation of supraventricular tachycardias

Purpose

The aim of this study was to evaluate the safety and efficacy of zero-fluoroscopy (ZF) catheter ablation (CA) for supraventricular tachycardias (SVT).

Methods

584 consecutive patients referred to our institution for CA of SVT were analysed. Patients were categorised into two groups; zero-fluoroscopy (ZF) group and conventional fluoroscopy (CF) group. The ZF group was further divided into two subgroups (adults and paediatric). Patient characteristics, procedural information, and follow-up data were compared.

Results

The ZF group had a higher proportion of paediatric patients (42.2% vs 0.0%; p < 0.001), resulting in a younger age (30.9 ± 20.3 years vs 52.7 ± 16.5 years; p < 0.001) and lower BMI (22.8 ± 5.7 kg/m2 vs 27.0 ± 5.4 kg/m2; p < 0.001). Procedure time was shorter in the ZF group (94.2 ± 50.4 min vs 104.0 ± 54.0 min; p = 0.002). There were no major complications and the rate of minor complications did not differ between groups (0.0% vs 0.4%; p = 0.304). Acute procedural success as well as the long-term success rate when only the index procedure was considered did not differ between groups (92.5% vs 95.4%; p = 0.155; 87.1% vs 89.2%; p = 0.422). When repeated procedures were included, the long-term success rate was higher in the ZF group (98.3% vs 93.5%; p = 0.004). The difference can be partially explained by the operators' preferences.

Conclusion

The safety and efficacy of ZF procedures in adult and paediatric populations are comparable to that of CF procedures.

Outcomes Of Manifest Right Free Wall Accessory Pathway Ablation: Data From A Single Center

Background

Right free wall (RFW) accessory pathways (AP) typically present anatomical challenges to ablation leading to high rates of procedural failure and recovery of AP conduction.

Methods

Patients with a diagnosis of Wolff-Parkinson-White Syndrome (WPW) and a manifest RFW AP undergoing an electrophysiology study (EPS) or an ablation at our center between 01/01/2008 and 08/01/2019 were identified from our databases using diagnosis codes and manual chart review.

Results

Twenty-one patients with manifest RFW AP underwent EPS, all of which were targeted for ablation. Single procedure success rate was 19 / 21 (90.5%). Of the 19 successful cases, 4 (17.4%) patients were found to have recurrent right free wall pathway conduction at follow-up and each underwent a successful 2nd procedure (9.5%). Fluoroscopic and 3D electroanatomic mapping software was used in all cases to guide ablation. A 4 mm or 8 mm non-irrigated radiofrequency (RF) ablation catheter was used in 76% of cases while an 8 mm cryo-catheter was used in one case. More than one type of ablation catheter was used in four cases (16%). A steerable sheath was used in 68% of cases.

Conclusions

In a tertiary center, RFW AP ablation has high acute success (>90%) but approximately 21% of patients with initially successful ablation required a 2nd procedure for recurrence of pathway conduction. A combination of a large tip ablation catheter and a steerable sheath were used in most cases.

Intracardiac Echocardiography to Guide Non-fluoroscopic Electrophysiology Procedures

Intracardiac echocardiography (ICE) is the most practical method for online imaging during electrophysiological procedures. It allows guiding of complex catheter ablation procedures together with electroanatomical mapping systems, either with minimal or with zero fluoroscopy exposure. Besides safe and reproducible transseptal puncture, ICE helps to assess location and contact of the tip of the ablation catheter relative to specific anatomical structures. Another option is visualization of the arrhythmogenic substrate in patients with ventricular arrhythmias. This article describes the clinical utility of ICE in non-fluoroscopic electrophysiology procedures more in detail.

Fluoroless catheter ablation of accessory pathways in adult and pediatric patients: a single centre experience

Catheter radio-frequency ablation (RFA) and cryo-ablation (CRA) procedures are an effective and safe treatment options for adult and pediatric patients with accessory pathway (AP) mediated tachycardias. Non-fluoroscopic techniques during catheter ablation (CA) procedures reduce potentially harmful effects of radiation. Our aim was to investigate the efficacy and safety of completely fluoroless RFA and CRA procedures in pediatric and adult patients with APs. Consecutive patients with AP-related tachycardia and high risk asymptomatic ventricular pre-excitation were assessed in retrospective analysis. Three-dimensional (3D) electro-anatomical mapping (EAM) and intra-cardiac echocardiography (ICE) were used as principal imaging modalities. Fluoroscopy was not used during any stage of the procedures. Among 116 included patients (22.76 ± 16.1 years, 68 patients < 19 years), 60 had left-sided APs, 16 right-sided APs and 40 septal APs. Altogether, 96 had RFA and 20 CRA procedures. The acute success rates (ASR) of RFA and CRA were 97.9% and 95%, respectively (p = 0.43), with recurrence rates (RR) of 8.33% and 40%, respectively (p < 0.0001). The outcome difference was principally driven by lower RR with RFA in septal APs (9.1% vs. 38.9%, p = 0.025). Pediatric patients with APs (12.21 ± 3.76 years) had similar procedural parameters and outcomes compared to adult patients. There were no procedure-related complications. In adult and pediatric patients with AP-related tachycardias, both CRA and RFA can be effectively and safely performed without the use of fluoroscopy. In addition, RFA resulted in better outcomes compared to CRA.