Ablation of residual potentials along the circumferential line reduces acute reconnection in patients undergoing pulmonary vein isolation

Introduction

Acute pulmonary vein (PV) reconnection is frequently encountered in patients with atrial fibrillation (AF) subjected to PV isolation (PVI).

Purpose

In this prospective, multicenter, randomized study, we investigated whether the identification and ablation of sites along the circumferential line with specific electrogram criteria indicative of nontrasmurality, after initial achievement of PVI, reduces acute PV reconnection rate.

Methods

Patients referred for AF ablation at five European centers were enrolled. PVI with antral circumferential isolation of ipsilateral PVs was performed using a contact force sensing ablation catheter delivering 35–40W at the anterior/superior and 30W at the posterior wall with target ablation index of 550 at the anterior wall/roof and 400 at the posterior/inferior segments. Following PVI, mapping with the ablation catheter was performed to identify residual potentials (RP) along the ablation line, defined as bipolar amplitude ≥0.2 mV or 0.1–0.19 mV combined with negative component of the unipolar electrogram as recorded by the 3D mapping system. Ipsilateral PV sets with RPs were randomized to either no further ablation (Group B) or to additional ablation of RPs (Group C). The primary study endpoint was defined as spontaneous or adenosine-mediated recovery of conduction after 30-minute waiting period which was also evaluated in ipsilateral PV sets without residual potentials (Group A).

Results

In total, 109 patients (59.3±10.6 years, 47% hypertension, 9.3% diabetes, left atrial diameter 39.1±4.6mm) were enrolled in the study. After initial isolation of 194 PV pairs, 98 PV pairs had no RPs (Group A) while the remaining 96 with RPs were randomized to either Group B or C (48 PV pairs each). The number of sites with RPs did not differ between groups B and C (4.1±2.5 vs 4.7±3.2, p=0.27). The occurrence of the primary endpoint in Group A was 7.1%. Ablation of residual potentials resulted in significant reduction of spontaneous or adenosine mediated reconnection (14.6% vs 47.9%, p<0.001).

Conclusion

Following initial PVI achievement, ablation of RPs along the antral circumferential line reduces spontaneous or adenosine-mediated acute PV reconnection rate in patients undergoing first-time AF ablation. Therefore, scanning of the PVI line in search of weak links with specific electrogram criteria indicative of nontrasmurality, and subsequent deployment of bonus lesions, could represent a convenient and practical way to reduce acute PV reconnection. Further studies are required to assess long term effects on AF recurrence rates.

Funding Acknowledgement

Type of funding sources: None.

Intermuscular implantation technique for subcutaneous cardioverter-defibrillators

BACKGROUND

The conventional technique for subcutaneous implantable cardioverter-defibrillator (S-ICD) implantation has been associated with pocket complications. The aim of this study was to evaluate the efficacy and safety of an alternative intermuscular technique for S‑ICD implantation.

METHODS

S-ICDs were implanted in ten consecutive patients (ten males, mean age: 46.8 ± 14.7 years). The pocket for the pulse generator was made above the serratus anterior muscular fascia and beneath the latissimus dorsi muscle by detaching the fibrous tissue between the muscles. Electrode implantation was performed using the three- (n = 4) or the two-incision technique (n = 6).

RESULTS

All S‑ICDs were successfully implanted in the absence of any procedure-related complications with a successful 65-J standard polarity defibrillation threshold testing, apart from one patient with Brugada syndrome who needed device repositioning more dorsally. During a mean follow-up of 16.5 ± 7.3 months, no major complications requiring surgical repair were encountered, while patients demonstrated high levels of comfort and satisfaction with the cosmetic result. One patient experienced an inappropriate shock due to noise detection, which was resolved after reprogramming to a different sensing vector.

CONCLUSION

The intermuscular technique is a safe and efficacious approach for S‑ICD implantation. This technique could lead to fewer pocket-related complications and better cosmetic results.