Electrophysiology: it is time to simplify!

Spontaneous Variation of Ventriculo-Atrial Interval after Tachycardia Induction: Determinants and Usefulness in the Diagnosis of Supraventricular Tachycardias with Long Ventriculoatrial Interval

Background: Determining the mechanism of supraventricular tachycardias with prolongedP ventriculoatrial (VA) intervals is sometimes a challenge. Our objective is to analyse the determinants, time course and diagnostic accuracy (atypical atrioventricular nodal reentrant tachycardias [AVNRT] versus orthodromic reentrant tachycardias through an accessory pathway [ORT]) of spontaneous VA intervals variation in patients with narrow QRS tachycardias and prolonged VA. Methods: A total of 156 induced tachycardias were studied (44 with atypical AVNRT and 112 with ORT). Two sets of 10 measurements were performed for each patient—after tachycardia induction and one minute later. VA and VV intervals were determined. Results: The difference between the longest and the shortest VA interval (Dif-VA) correlates significantly with the diagnosis of atypical AVNRT (C coefficient = 0.95 and 0.85 after induction and at one minute, respectively; p < 0.001). A Dif-VA ≥ 15 ms presents a sensitivity and specificity for atypical AVNRT of 50% and 99%, respectively after induction, and of 27% and 100% one minute later. We found a robust and significant correlation between the fluctuations of VV and VA intervals in atypical AVNRTs (Coefficient Rho: 0.56 and 0.76, after induction and at one minute, respectively; p < 0.001 for both) but not in ORTs. Conclusions: The analysis of VA interval variability after induction and one minute later correctly discriminates atypical AVNRT from ORT in almost all cases.

Initial experience with a novel re-sterilisable decapolar electrophysiology catheter

PURPOSE

Diagnostic electrophysiology catheters are single-use and their expense can act as a barrier to their use. A decapolar catheter with a re-sterilisable handle and inner core was developed, along with a disposable outer sheath. This initial experience evaluated the performance of the Khelix partially recyclable steerable decapolar electrophysiology catheter.

METHODS

Sequential patients requiring a decapolar steerable catheter were included in the study. Parameters such as time to positioning from right femoral vein, fluoroscopy time and dose, pacing and sensing thresholds, and the requirement for reposition and/or support sheath were recorded. A retrospective analysis from cases using a standard disposable decapolar catheter was used to compare CS cannulation success, support sheath requirement and cost.

RESULTS

11 re-sterilisable catheter handles were used in 64 patients, each time with a disposable sheath, at two New Zealand centres from December 2017 to June 2018. Pre-defined safety measures were met in all patients, with no catheter-related adverse events. The catheter was successfully positioned in the coronary sinus for 59 cases (92%). Based on initial manufacturer recommendations, the inner recyclable portion of the catheter was able to be re-used successfully up to 12 times with re-sterilisation between cases.

CONCLUSIONS

This initial study of an innovative, partially reusable, steerable decapolar electrophysiology catheter demonstrates that it may be used safely and successfully. Use of such a catheter may decrease the cost required for electrophysiology studies.

Feasibility of implementation of a "simplified, No-X-Ray, no-lead apron, two-catheter approach" for ablation of supraventricular arrhythmias in children and adults

INTRODUCTION

Although the "near-zero-X-Ray" or "No-X-Ray" catheter ablation (CA) approach has been reported for treatment of various arrhythmias, few prospective studies have strictly used "No-X-Ray," simplified 2-catheter approaches for CA in patients with supraventricular tachycardia (SVT). We assessed the feasibility of a minimally invasive, nonfluoroscopic (MINI) CA approach in such patients.

METHODS

Data were obtained from a prospective multicenter CA registry of patients with regular SVTs. After femoral access, 2 catheters were used to create simple, 3D electroanatomic maps and to perform electrophysiologic studies. Medical staff did not use lead aprons after the first 10 MINI CA cases.

RESULTS

A total of 188 patients (age, 45 ± 21 years; 17% <19 years; 55% women) referred for the No-X-Ray approach were included. They were compared to 714 consecutive patients referred for a simplified approach using X-rays (age, 52 ± 18 years; 7% <19 years; 55% women). There were 9 protocol exceptions that necessitated the use of X-rays. Ultimately, 179/188 patients underwent the procedure without fluoroscopy, with an acute success rate of 98%. The procedure times (63 ± 26 vs. 63 ± 29 minutes, P > 0.05), major complications (0% vs. 0%, P > 0.05) and acute (98% vs. 98%, P > 0.05) and long-term (93% vs. 94%, P > 0.05) success rates were similar in the "No-X-Ray" and control groups.

CONCLUSIONS

Implementation of a strict "No-X-Ray, simplified 2-catheter" CA approach is safe and effective in majority of the patients with SVT. This modified approach for SVTs should be prospectively validated in a multicenter study.

Catheter ablation for supraventricular tachycardias: contemporary issues

The treatment of cardiac arrhythmias has evolved significantly over the last 30 years. Understanding of arrhythmia mechanisms has led to pharmacologic therapies, surgical interventions and the widely used percutaneous catheter ablation techniques. The focus of this review is centered on the current catheter ablation therapies available for supraventricular tachycardia. We will discuss current management strategies including challenges when considering catheter ablation therapy for management of supraventricular tachycardias: atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia utilizing an accessory pathway, atrial tachycardia and atrial flutter. Selected contemporary issues related to supraventricular tachycardia physiology, ablation approaches and ablation outcomes and complications will be discussed. Future goals for electrophysiologists are to continue to improve procedural safety and efficiency, while maintaining the impressive success rates that have been achieved.