Teaching Case

Pulmonary vein isolation was performed in a 52-year-old male to treat paroxysmal atrial fibrillation. The procedure, carried out under general anaesthesia, was uneventful. Eight days after the treatment, the patient developed retrosternal pain aggravated by inspiration, followed by neurological symptoms (dysarthria, decreased consciousness and right hemiparesis), right pelvic pain and eventually septic shock.

In the workup, the following investigations were performed over a couple of days, listed chronologically.

Transthoracic ultrasound showed a cardiac tamponade, which was immediately drained.

Contrast-enhanced chest CT showed a pericardial drain with moderate residual fluid, retrocardial pneumomediastinum, peri-oesophageal mediastinitis, air in the left atrial auricle and ventricle and bilateral pleural effusion. The presence of an atrio-oesophageal fistula (AEF) was suggested. 

MRI of the brain revealed multifocal, bilateral, acute ischemic lesions in the cortex and basal ganglia, supposedly caused by air or septic emboli. Some lesions showed haemorrhagic transformation.

Pelvic MRI demonstrated an abscess of septic embolic origin in the right internal obturator muscle, which was drained with CT guidance.

After surgical treatment (mediastinal debridement, resection of the posterior left atrial wall and repair with xenopericardial patch) and endoscopic clipping of an oesophageal perforation, a gastrographin meal was performed. Anterior extra-oesophageal contrast leakage was demonstrated nearby the endoscopic placed clips, opacifying a necrotic cavity.

Apart from confirming the abovementioned infectious processes, postoperative PET-CT also showed clinically suspected endocarditis posterior in the left atrium near the operation region, bilateral multifocal nephritis and focal myositis of the left pectoralis major muscle.

Blood cultures were positive for multiple bacteria (streptococcus pyogenes, lactobacillus, pseudomonas, enterococcus, staphylococcus epidermidis) during a period of 6 weeks despite continuous broad spectrum antibiotics.

Background

Pulmonary vein isolation is an increasingly performed procedure to treat drug-resistant atrial fibrillation. Circumferential lesions around the pulmonary vein ostia are created by various methods, mostly radiofrequency ablation, disrupting aberrant electrical circuits causing atrial fibrillation. Cardiac CT with volume rendering reconstruction of the left atrium and the variable anatomy of pulmonary vein ostia is routinely used as a roadmap during the procedure. The risk of a major complication is around 6% and 90-day postprocedural mortality around 0.1% [1,2]. Acute or subacute complications comprise cardiac tamponade due to perforation, thromboembolic events, oesophageal thermal lesions and AEF. Pulmonary vein stenosis due to fibrosis occurs in the chronic setting. Although the incidence of an AEF is estimated at around 0.016%, it is frequently fatal [3].

Clinical perspective

Symptom onset for oesophageal perforation or AEF is variable, ranging from 1 to 8 weeks with an average of 19 days [3]. Clinical presentation is atypical, often leading to a delayed diagnosis. Possible symptoms include malaise, fever, chest pain, nausea, dysphagia, hematemesis and melena. Early suspicion is important as the development of endocarditis can rapidly lead to neurological failure, decreased consciousness, seizures and coma as illustrated in this case.

Imaging perspective

Imaging plays an important role in the diagnosis since endoscopy is theoretically contra-indicated. Oesophageal insufflation poses the risk of increasing the fistula size and inducing air embolism [4].

Contrast-enhanced chest CT is the test of choice, able to eventually suggest the presence of an AEF in 98% of cases [4]. Possible findings include pneumomediastinum, pneumopericardium, air in the left atrium or ventricle, mediastinitis and contrast leakage from the left atrium into the mediastinum or oesophagus. However, initial CT may be unremarkable. Repeat chest CT after a few days may be required to establish the diagnosis in 7% of cases [4].

Ingestion of gastrographin can demonstrate extra-oesophageal contrast leakage.

The use of other imaging investigations is determined by clinical symptoms, as in this case.

Outcome

Overall mortality in patients with AEF is estimated at around 55%, with only 17% of surviving patients making complete recovery [4].

Treatment options for AEF include surgery, oesophageal stenting and conservative management, the latter being controversial, as it is associated with very high mortality rate (97%). One study found significantly lower mortality in operated patients (33%) compared to endoscopically treated patients (65%), although this also depends on patient comorbidity [4].

Take home message

AEF is a rare but often fatal complication of pulmonary vein ablation. Contrast-enhanced chest CT is the diagnostic test of choice since endoscopy may induce clinical deterioration. Although early diagnosis is essential to minimize mortality, repeat CT may be required to establish the diagnosis.

Written informed patient consent for publication has been obtained.