Sandeep Panikker

Pulmonary vein isolation (PVI) is the cornerstone of catheter ablation for atrial fibrillation (AF). There are limited data on the PolarX Cryoballoon. The study aimed to establish the safety, efficacy, and feasibility of same day discharge for Cryoballoon PVI. Multi-centre study across 12 centres. Procedural metrics, safety profile, and procedural efficacy of the PolarX Cryoballoon with the Arctic Front Advance (AFA) Cryoballoon were compared in a cohort large enough to provide definitive comparative data. A total of 1688 patients underwent PVI with cryoablation (50% PolarX and 50% AFA). Successful PVI was achieved with 1677 (99.3%) patients with 97.2% (n = 1641) performed as day case procedures with a complication rate of P < 0.001] and nadir temperature (OR 1.24; P < 0.001) with an optimal cut-off of ≤34 s [area under the curve (AUC) 0.73; P < 0.001] and nadir temperature of ≤−54.0°C (AUC 0.71; P < 0.001), respectively. This large-scale UK multi-centre study has shown that Cryoballoon PVI is a safe, effective day case procedure. PVI using the PolarX Cryoballoon was similarly safe and effective as the AFA Cryoballoon. The cryoablation metrics achieved with the PolarX Cryoballoon were different to that reported with the AFA Cryoballoon. Modified cryoablation targets are required when utilizing the PolarX Cryoballoon. Demonstrates the spread of temperature profiles on a per vein basis with the PolarX Cryoballoon for cryoablations with a TTI that demonstrated successful PVI.

Background Transvenous lead extraction (TLE) for implantable cardiac-devices is traditionally performed under general anesthesia (GA). This can lead to greater risk of exposure to COVID-19, longer recovery-times and increased procedural-costs. We report the feasibility/safety of TLE using conscious-sedation alone with immediate GA/cardiac-surgery back-up if needed. Methods Retrospective case-series of consecutive TLEs performed using conscious-sedation alone between March 2016 and December 2019. All were performed in the electrophysiology-laboratory using intravenous Fentanyl, Midazolam/Diazepam with a stepwise approach using locking-stylets/cutting-sheaths, including mechanical-sheaths. Baseline patient-characteristics, procedural-details and TLE outcomes (including procedure-related complications/death) were recorded. Results A total of 130 leads were targeted in 54 patients, mean age ± SD 74.6 ± 11.8years, 47(87%) males; dual-chamber pacemakers (n = 26; 48%), cardiac resynchronization therapy-defibrillators (n = 17; 31%) and defibrillators (n = 8; 15%) were commonest extracted devices. Mean ± SD/median (range) lead-dwell times were 11.0 ± 8.8/8.3 (0.3-37) years, respectively. Extraction indications included systemic infection (n = 23; 43%) and lead/pulse-generator erosion (n = 27; 50%); mean 2.1 ± 2.0 leads were removed per procedure/mean procedure-time was 100 ± 54 min. Local anesthetic (LA) was used for all (mean-dose: 33 ± 8 ml 1% lidocaine), IV drug-doses used (mean ± SD) were: midazolam: 3.95 ± 2.44 mg, diazepam: 4.69 ± 0.89 mg and fentanyl: 57 ± 40 µg. Complete lead-extraction was achieved in 110 (85%) leads, partial lead-extraction (<4 cm-fragment remaining) in 5 (4%) leads. Sedation-related hypotension requiring IV fluids occurred in 2 (managed without adverse-consequences) and hypoxia requiring additional airway-management in none. No procedural deaths occurred, one patient required emergency cardiac surgery for localized ventricular perforation, nine had minor complications (transient hypotension/bradycardia/pericardial effusion not requiring intervention). Conclusion TLE undertaken using LA/conscious-sedation was safe/feasible in our series and associated with good clinical outcome/low procedural complications. Reduced risk of aerosolization of COVID-19 and quicker patient recovery/reduced anesthetic risk are potential benefits that warrant further study.

Background: Circulatory collapse during/post-pulmonary vein (PV) isolation by cryo-balloon ablation is a Cardiology emergency that has multiple potential causes and requires a methodical investigative approach. Some of the complications that can arise include cardiac tamponade, bleeding/vascular injury, anaphylaxis, Addisonian crisis, acute pulmonary embolism, acute PV stenosis, oesophageal injury, and vagal reaction. Case summary: Here, we present a case of a 76-year-old lady who developed profound circulatory collapse during an elective pulmonary vein isolation by cryo-balloon ablation for symptomatic paroxysmal atrial fibrillation (AF). Cardiac tamponade, bleeding/vascular injury, and other less common causes were excluded. She only responded transiently to fluid resuscitation and developed intermittent bradyarrhythmias and hypotension which responded to isoprenaline. She was discharged home at Day 3 post-AF ablation after remaining well and continued to do so at follow-up. Discussion: Circulatory collapse during/post-PV cryo-balloon ablation is a Cardiology emergency that has multiple potential causes. The ganglionate plexi form part of the cardiac intrinsic autonomic nervous system (ANS) and are located close to the left atrial–PV junctions. The presence of vagal response has been observed to be a marker of ANS modulation although its significance on the long-term outcome post-ablation has yet to be elucidated. The true cause of our patient’s profound circulatory collapse is uncertain but a vital learning point in this case is the systematic exclusion of common and potentially life-threatening complications following AF ablation. A persistent vagal reaction secondary to PV cryo-balloon ablation can usually be managed with supportive medical therapy as demonstrated in our case.

Purpose of the study: Left atrial appendage (LAA) electrical isolation may improve the efficacy of persistent atrial fibrillation (AF) ablation. We have previously demonstrated substantial acute LAA reconnection rates in both canines and humans following electrical isolation. We sought to establish whether LAA ostial thickness variations could be evaluated by a novel computational algorithm applied to a pre-procedure CT. Methods used: LAA wall thickness was calculated by solving the Laplace equation between the boundary conditions assigned to the endo- and epi-cardial surfaces from CT scans of 20 patients. Comparison was made with acute LAA reconnection sites in 20 patients with longstanding persistent AF undergoing LAA isolation following conventional AF ablation and with ostial LAA thicknesses from a group of cadaveric human hearts without previous ablation matched with the ablation group. Summary of the results: The anterior (2.5 ± 0.8 mm) and superior (2.4 ± 1.2 mm) LAA margins were thickest histologically. This correlated with recorded sites of acute reconnection. The algorithm calculated thicker tissue at the same ostial sites. The thickest region was at the anterior wall; the inferior wall was the thinnest (2.4 ± 1.5 mm vs 1.8 ± 0.8 mm, p = 0.039). Conclusion: Additional LAA electrical isolation may improve persistent AF ablation efficacy. Acute LAA reconnection rates are substantial, and correlate with regions of thicker ostial tissue. This novel algorithm allows accurate delineation of LAA ostial sites with thickest tissue and correlates with clinically observed reconnection sites and with histological analysis. Identification of these sites may improve ablation efficacy and durability of LAA isolation.