Phrenic nerve injury contemporaneous with acute decrease in compound motor action potential during laser balloon pulmonary vein isolation for atrial fibrillation

Laser balloon ablation of atrial fibrillation in a patient with a large common inferior trunk: a case report

Background

A balloon-based visually guided laser balloon (LB) ablation (LBA) is as effective and safe as radiofrequency ablation and cryoballoon ablation in curing patients with atrial fibrillation (AF). The third-generation LB is so compliant that it can be inflated to any pressure and size change of up to 41 mm with its maximal expansion, which enables maximum balloon/tissue contact regardless of the size or shape of each pulmonary vein (PV) ostium. A large common inferior trunk (CIT) with a structured, completely independent common ostium of both the right and the left inferior PVs completely conjoined prior to the junction with the left atrium is an extremely rare anatomical variant and an important triggering focus in paroxysmal AF.

Case summary

We present a case of an LBA of AF in a patient with a large CIT of 34 mm in diameter. The laser energy was individually deployed to the right-sided and left-sided antra of the large CIT with the LB positioned at the ostium of the CIT's right and left branches. The complete electrical isolation of the three PVs was achieved. The patient remained stable without any symptoms or AF recurrence 1 year post ablation.

Discussion

The LBA, which is individually deployed to the right-sided and left-sided antra of the large CIT with the third-generation LB positioned at the ostium of the right and left branches of the CIT without laser energy deployment to the posterior wall of the CIT, may be one of the effective strategies for patients with large CITs.

Predictors of Phrenic Nerve Injury During Pulmonary Vein Isolation for Curing Atrial Fibrillation With Balloon-Based Visually Guided Laser Ablation

BACKGROUND

Pulmonary vein (PV) isolation (PVI) with balloon-based visually guided laser ablation (VGLA) is useful for treating atrial fibrillation (AF), but phrenic nerve injury (PNI) is an important complication. We investigated the predictors of developing PNI during VGLA.

METHODS AND RESULTS

We included 130 consecutive patients who underwent an initial VGLA of non-valvular paroxysmal AF. Twenty patients developed PNI during the PVI. The patients with PNI had a significantly larger right superior PV ostial area (RSPVOA) than the other patients (mean [±SD] 284.7±47.0 vs. 233.1±46.4 mm2, respectively; P<0.01). Receiver operating characteristic analyses revealed that the area under the RSPVOA curve was 0.79 (95% confidence interval [CI] 0.69-0.90) with an optimal cut-off point of 238.0 mm2(sensitivity, 0.58; specificity, 0.95). In multivariate analyses, a large RSPVOA (HR 1.02, 95% CI 1.01-1.03, P<0.01) and small balloon size (HR 0.70, 95% CI 0.50-0.99, P=0.04) were independent risk factors for PNI during VGLA. PNI remained in 13 patients after the procedure, but 12 of these patients recovered from the PNI during the follow-up period.

CONCLUSIONS

The incidence of PNI during VGLA was relatively high, but PNI improved in most cases. A large RSPVOA and small balloon size were predictors of PNI during VGLA.