What are the considerations for pulse ablation in a patient with a history of Coronary Artery Bypass Grafting (CABG), atrial clip, and Barrett's esophagus?

Pulsed Field Ablation in a 68-Year-Old Post-CABG Patient with Atrial Clip and Barrett's Esophagus

Pulsed field ablation (PFA) is the preferred ablation modality for this patient because it selectively spares the esophagus while the atrial clip requires careful pre-procedural imaging and potentially modified catheter approaches, but does not represent an absolute contraindication.

Primary Safety Advantage: Esophageal Protection

PFA offers a critical safety advantage over thermal ablation methods specifically because of the Barrett's esophagus. The tissue selectivity of PFA means it does not induce esophageal injury on cardiac MRI after pulmonary vein isolation, with 0% oesophageal lesion rates compared to 43% with thermal methods (radiofrequency or cryoballoon) 1. This is particularly important because:

• Thermal ablation causes oesophageal lesions in 43% of cases where direct contact exists between the esophagus and ablation sites 1
• PFA showed no oesophageal lesions despite similar rates of direct esophageal-ablation site contact 1
• Post-procedure esophagogastroduodenoscopy after PFA revealed no mucosal lesions 2
• The risk of atrio-esophageal fistula, a catastrophic complication, is essentially eliminated with PFA 3

Barrett's Esophagus Management Considerations

The presence of Barrett's esophagus creates competing treatment priorities that must be sequenced appropriately:

• If the Barrett's contains dysplasia (low-grade or high-grade), endoscopic radiofrequency ablation of the Barrett's should be performed first before cardiac ablation, as this reduces cancer progression risk by 25% over 3 years 4 and is a Class B recommendation 5
• The British Society of Gastroenterology recommends RFA for flat dysplasia in Barrett's esophagus with a superior safety profile compared to other ablation modalities 5
• Critical timing issue: If Barrett's ablation is needed, complete it first and allow 3-4 weeks for esophageal healing before proceeding with cardiac PFA 5
• Optimize proton pump inhibitor therapy throughout both procedures to reduce acid reflux and promote healing 6

Atrial Clip Technical Considerations

The atrial clip from previous CABG surgery requires specific pre-procedural planning but is not prohibitive:

• Obtain high-resolution cardiac CT or MRI pre-procedure to map the exact location of the atrial clip relative to planned ablation sites 6
• Metal clips can cause electrical interference and create concentrated energy areas during ablation, increasing perforation risk with thermal methods 6
• The clip interferes with catheter manipulation and energy delivery, requiring modified catheter approaches 6
• PFA's advantage: The non-thermal mechanism reduces the risk of clip-related energy concentration compared to radiofrequency ablation 1

Post-CABG Arrhythmia Assessment

Before proceeding with any ablation, determine the arrhythmia mechanism:

• First-line treatment is medical management with β-blockers (Class I, Level A recommendation) before considering ablation in post-CABG patients with atrial fibrillation 6
• Evaluate whether the arrhythmia is ischemia-driven versus scar-mediated from the CABG procedure 5
• If life-threatening ventricular arrhythmias are present with 3-vessel disease, CABG itself would be indicated (Class I) 5, but this patient already has CABG
• Document that medical management has been optimized (β-blockers, amiodarone, sotalol) before ablation 6

Procedural Approach Algorithm

Step 1: Assess Barrett's dysplasia status

• Perform upper endoscopy with systematic biopsies
• If dysplasia present → treat Barrett's first with RFA 5, 4
• Wait 3-4 weeks for healing before cardiac ablation

Step 2: Optimize medical management

• Maximize β-blocker therapy for arrhythmia control 6
• Optimize PPI therapy for Barrett's protection 6
• Document failure of medical management before proceeding

Step 3: Pre-procedural imaging

• High-resolution cardiac CT/MRI to map atrial clip location 6
• Assess esophageal position relative to posterior left atrium 1
• Plan catheter approach to avoid clip interference

Step 4: Select PFA over thermal ablation

• Use multispline PFA catheter for pulmonary vein isolation 2
• Intracardiac echocardiographic guidance mandatory 2
• No esophageal protection strategy needed (unlike thermal ablation) 2
• Expect procedure time ~125 minutes with ~16 minutes fluoroscopy 2

Critical Pitfalls to Avoid

• Do not use thermal ablation (radiofrequency or cryoballoon) in this patient given the Barrett's esophagus and 43% risk of esophageal injury 1
• Do not proceed with cardiac ablation if Barrett's dysplasia is untreated, as this creates unnecessary cancer progression risk 4
• Do not assume the atrial clip is a contraindication to ablation, but do obtain detailed imaging first 6
• Do not skip post-procedural esophagogastroduodenoscopy even with PFA, to document absence of esophageal injury 2
• Be aware that even esophageal RFA for Barrett's can rarely trigger atrial flutter (one case report), requiring cardioversion 7

Post-Procedural Monitoring

• Invasive remapping at 2-3 months demonstrates 96% durable pulmonary vein isolation with PFA 2
• Continue PPI therapy indefinitely for Barrett's management 6
• Cardiac MRI at 3 months to assess for any delayed complications 1
• Resume Barrett's surveillance schedule per gastroenterology guidelines 5