Background

Chest pain after thermal cardiac ablation is common, probably caused by pericardial ablation and inadverted ablation of collateral tissue, e.g. esophagus. Pulsed field ablation (PFA) (Farapulse, Inc.) is a novel, nonthermal ablation modality that preferentially ablates myocardial tissue, with minimal collateral effect on surrounding tissues. Therefore, there is no necessity to reduce the ablation power. In preclinical studies, it has been demonstrated that PFA can create deeper and larger myocardial lesions. The ablation catheter is inserted through a novel 16.8F outer diameter steerable sheath. This study aims to quantify chest and groin pain after PFA in patients with paroxysmal atrial fibrillation.

Methods

During deep sedation and after local anesthesia, an 8F and an 8.5F sheath were inserted in the right femoral vein. After transseptal puncture, the 8.5F sheath was exchanged for a 16.8F outer diameter steerable sheath to accomodate the multispline ablation catheter. Biphasic pulse trains with a power of 1,900 V were applied. A minimum of 8 ablation applications per pulmonary vein was required. After the PVI, the femoral vein was closed using a Z-suture. After approx. 3 hours, the patients were allowed to mobilize cautiously. The morning after the ablation, the Z-suture was removed. To determine the severity of chest and groin pain, a numeric pain score (Numeric Rating Scale (NRS)) was used. Patients were asked to choose a number ranging from 0 to 10, where 0 represented „no pain at all“ and 10 represented „the worst pain possible“. The NRS was completed before PVI and 6h, 24h, 48h and 30 days after PVI.

Results

In 30 patients (mean age 63 ± 10 years; 47% male; CHA₂DS₂-VASc-Score 2 [IQR 1-3]), PFA was performed, with all PVs acutely isolated. No groin hematoma occured. In 1 patient, an uncomplicated pericardial drainage after late cardiac tamponade was performed. 

„Slightly pronounced discomfort“ was mostly stated as groin pain during the in-hospital stay. Median pain scores of the groin were 0; 1; 1; 1; 0 at baseline and 6h, 24h, 48h and 30 days after PVI, respectively. In 29 patients, pain scores for the chest were 0 at all pre- and post-ablation intervals. In the patient with the pericardial drainage after late cardiac tamponade, pain scores were 0; 1; 3; 2; 0 at baseline and 6h, 24h, 48h and 30 days after PVI, respectively.

Conclusions

1. Use of the novel 16.8F outer diameter steerable sheath and subsequent Z-suture barely causes any pain in the groin.

2. Uncomplicated PVI using PFA for PAF is does not cause any chest pain. The reason might be the different mechanism of cell death: e.g. RF ablation creates thermal coagulation necrosis with release of inflammatory mediators, whereas PFA induces necrosis, apoptosis, necroptosis and pyroptosis and less inflammatory response. Also, (subclinical) collateral damage cannot be excluded when using thermal ablation, pericarditis, pleuritis and injury to the esophagus and bronchial system are possible sources of chest pain.

3. Thirty days after PVI, all patients were free of pain.