Treatment Of Accessory Pathways Research Articles

Multi-catheter cryotherapy for the treatment of resistant accessory pathways

ObjectiveTo investigate the utility of simultaneous multi-catheter cryotherapy for the treatment of APs that were previously resistant to standard radiofrequency (RF) catheter ablation. BackgroundCatheter ablation is established in the treatment of accessory pathways (AP), with high rates of permanent procedural success with a single attempt. However, there are still instances of acute procedural failure and AP recurrences with standard RF and cryotherapy methods. MethodsSeven consecutive cases of pre-excitation syndromes with prior failed RF catheter ablation had the novel treatment. Cryotherapy was delivered using two 8 mm tip focal cryoablation catheters (Freezor® Max, Medtronic, Minneapolis, Minnesota, USA). ResultsAccessory pathway localisation was septal in 5 cases, left posterolateral in 1, right lateral in 1. In all cases, ablation of the AP was acutely successful with no procedural complications. Median procedure and fluoroscopy durations were 199 and 35 min, sequentially. Median Procedure duration fell significantly in the second half of series (174 min) compared to the first half (233 min, P = 0.05). One patient had evidence of a recurring AP conduction with pre-excitation at 5-week follow up. After a median follow up of 66.8+-6.5 months, 6 out of 7 patients remained asymptomatic and free of pre-excitation. ConclusionSimultaneous multi-catheter cryotherapy is feasible, safe and can provide definitive cure of accessory pathways that were previously resistant to standard radiofrequency ablation. Further study is required in the assessment of this novel form of advanced cryotherapy to treat complex and resistant arrhythmias.

Evaluation of left atrial and left ventricular functions in patients with Wolff-Parkinson-White syndrome before and after radiofrequency catheter ablation using three-dimensional speckle tracking echocardiography.

Wolff-Parkinson-White (WPW) syndrome is one of the most common congenital cardiac abnormalities among ventricular pre-excitation syndromes. Radiofrequency catheter ablation (RFCA) treatment of accessory pathways (APs) in WPW patients is an established curative therapy restoring normal atrioventricular conduction. We have not encountered any studies evaluating both the LA and LV functions of these patients before and after RFCA with three dimensional-speckle tracking echocardiography (3D-speckle tracking echocardiography (STE)). The purpose of the current study was to assess the LA and LV functions in patients with WPW syndrome before and after RFCA using 3D-STE. A total of 21 patients with WPW syndrome who had been scheduled for RFCA were prospectively recruited for this study. 3D-STE examinations of the patients were performed 12-24h before ablation and 1 month after ablation. The LV-global longitudinal strain (LV-GLS) and LV-global circumferential strain (LV-GCS) were significantly depressed in the pre-RFCA WPW group than in the control group (-14.3±2.1vs. -21.5±2.2, p<.001; -12.6±1.8vs. -20.4±1.8, p<.001, respectively). The left atrial strain-reservoir (LAS-r) and LAS-active were significantly decreased in the pre-RFCA WPW group than in the control group (31.9±2.4vs. 48.8±2.6, p<.001; 11.7±2vs. 26.5±2.1, p<.001, respectively). The LV-GLS, LV-GCS, LAS-r, and LAS-active values improved after RFCA compared to before. The results of our study indicated that there are subclinical impairments in LV and LA myocardial dynamics in the apparently healthy WPW patients, and these deteriorations improve after RFCA of AP.

Algorithms to Identify Accessory Pathways' Location on the 12-Lead Electrocardiogram.

The ability to estimate accessory pathway (AP) position enables pre-procedural planning, reduces mapping times, and improves risk estimates as part of the patient consent process. In this article, the nomenclature and important concepts of AP localization algorithms are outlined. An overview of three prominent algorithms is then provided. Each represents an era of invasive treatment of APs: surgical therapy, endocardial ablation, and contemporary electroanatomic mapping. In this manner, the premises, pitfalls, and evolution of AP localization algorithms are illustrated. In addition, the pertinent features of their work are distilled in a simplified topographic algorithm with the interventional electrophysiologist in mind.

Risk factors of atrial fibrillation recurrence despite successful radiofrequency ablation of accessory pathway: At 11 years of follow-up.

Previous reports on patients with radiofrequency catheter ablation (RFCA) of accessory pathway (AP) and atrial fibrillation (AF) include only short follow-up periods. The aim of this study was to analyze predictors of recurrence of AF in patients after successful RFCA of APs over long term follow-up periods. Of the 1,007 patients who underwent non-pharmacological treatment of APs (between the years 1993-2008), data of 100 consecutive patients were retrospectively analyzed (75 men, mean age 43.6 ± 14.7), with the longest period of follow-up (mean 11.3 ± 3.5 years) after successful RFCA of AP. In Group 1, there were 72 patients (54 men, mean age 40.66 ± 13.85 years) without documented episodes of AF after RFCA of AP. Group 2 consisted of 28 patients (21 men, mean age 50.79 ± 14.49 years) with AF episodes despite successful elimination of AP. In univariate analysis, patients from Group 1 were significantly younger at the time of abla-tion than patients from Group 2 (40.66 ± 13.85 vs. 50.79 ± 14.49 years; p = 0.002), had shorter his¬tory of AF episodes (4.11 ± 4.07 vs. 8.25 ± 7.50 years; p = 0.024) and had less frequently documented atrial tachycardia (AT) prior to ablation (3.39 vs. 20.00% years; p = 0.022). In multivariate analysis, the history of AF in years (p = 0.043), was an independent risk factor for AF recurrences. Older patient age, longer history of AF and AT prior to RFCA of APs identified a sub-group of patients who required additional treatment. In the multivariate analysis, the history of AF in years (p = 0.043) was a risk factor for AF recurrence.

Safety and efficacy of cryoablation vs. radiofrequency ablation of septal accessory pathways: systematic review of the literature and meta-analyses.

Radiofrequency ablation (RFA) of septal accessory pathways (APs) is associated with a significant rate of first procedure failures and complications. Cryoablation is an alternative energy source but there are no studies comparing both ablation techniques. We aimed to systematically review the literature and compare the efficacy and safety of cryoablation vs. RFA of septal APs. We conducted two separate meta-analysis of cryoablation and RFA of septal APs and calculated the global estimates of the efficacy and safety. Sixty-four articles were included: 38 articles reporting RFA and 27 articles reporting cryoablation procedures. Additionally, we included the previously non-published cryoablation registry of septal APs performed at our institution. Overall, 4244 septal APs constitute our study population, 3495 in the RFA cohort and 749 in the cryoablation cohort. Acute procedural success rate of cryoablation was 86.0% (95% CI 81.6-89.4%) and RFA 89.0% (95% CI 86.8-91.0%). Recurrence rate of cryoablation was 18.1% (95% CI 14.8-21.8%) and RFA 9.9% (95% CI 8.2-12.0%). Long-term success rate after multiple ablation procedures of cryoablation was 75.9% (95% CI 68.2-82.3%) and RFA 88.4% (95% CI 84.7-91.3%). There were no reported cases of persistent atrioventricular block (AVB) with cryoablation and 2.7% (95% CI 2.2-3.4%) with RFA. Studies of RFA for treatment of septal APs report higher efficacy rates than do studies using cryoablation, but a significantly higher rate of AVB.

Efficacy and Safety of Cryoablation of Parahissian Accessory Pathways in Children: A Single Institution Study

Catheter cryoablation of supraventricular tachycardias involving the perinodal regions is considered to be a safer alternative compared to radiofrequency ablation. Limited information is available for efficacy, midterm outcomes, and complications regarding the ablation of parahissian accessory pathways (APs) in pediatric patients. A retrospective review of all pediatric patients who underwent cryoablation for treatment of a parahissian AP was performed. Twenty-five patients (median age 13 years and weight 45.6 kg) underwent cryoablation of a parahissian AP. Median number of cryolesions applied was four (range: 3-6). Initial procedural success was achieved in 23 patients (23/25, 92%). Transient third-degree atrioventricular (AV) block was noted in two patients. There was no permanent AV block. Transient right bundle branch block (RBBB) was observed in one patient and permanent RBBB occurred in two patients. Of the patients successfully ablated with cryo, there was only one recurrence (1/23, 4.3%) over a follow-up of 17.5 months (range 6-34 months). Cryoablation of parahissian APs is both safe and effective with a low risk of recurrence in pediatric patients.

Acute Success of Cryoablation of Left‐Sided Accessory Pathways: A Single Institution Study

To compare the acute success and recurrence rate of cryoablation for left-sided accessory pathways (AP) with controls who underwent radiofrequency ablation (RFA) at the same institution. Catheter cryoablation of supraventricular tachycardia (SVT) is considered to be a safer alternative a compared with RFA. At our institution, cryoablation has become the primary interventional modality for all APs. The reported success rates of cryoablation for AP-mediated tachycardia have generally been less favorable than for RFA. However, the location of AP may influence cryoablation outcome. Furthermore, there are little data available on cryoablation of left-sided pathways. A chart review was performed for all patients undergoing cryoablation between August 2005 and August 2007. Twenty-nine patients (mean age 13 years, range 6-18 years) were identified with SVT secondary to left-sided AP. The data collected included patient age, height, weight, date of procedure, mapping, ablation and procedure time, pathway location, success, and recurrence. Cryoablation was performed via a transseptal approach. Procedural success and recurrence rate were compared with our most recent 28 patients undergoing RFA ablation. Procedural success was achieved in 97% of patients in the cryoablation group, compared with 100% in the RFA control group. Recurrence rate in the cryoablation group was 1 of 24 (4.2%) patients compared with 4 of 28 (14%) patients in the RFA group over 12 months. Cryoablation can be safely and effectively used in the treatment of left-sided AP. Long-term outcomes remain to be seen.