The patient's hospital course was complicated by Streptococcus mitis bacteremia with no evidence of infective endocarditis on transthoracic echocardiogram. After 20 days of hospitalization, the patient was discharged home on intravenous antibiotics for a six-week treatment and continued outpatient rehabilitation. On a 3-month outpatient follow-up, the patient had significant clinical improvement overall, with mild left-sided neurological deficits.
AEF is a rare complication that occurs in 0.1%–0.25% of AF ablation procedures with a higher prevalence among men compared with women.1,2 Symptom onset for AF ablation complications has been reported to occur around 19–20 days postprocedure (although it can vary between 1 and 6 weeks), with delayed diagnosis typically suggestive of AEF carrying high mortality.3,4 This time frame was similar for our patient who presented approximately 3 weeks after the ablation procedure. The close proximity of the anterior esophagus and the posterior left atrial wall allows for this fistula formation, typically serving as a one-way valve from the esophagus into the atrium.1 There are various proposed mechanisms of injury, including direct thermal injury, exacerbation of or new-onset gastroesophageal reflux disease caused by ablation, infection from the lumen, and ischemic injury due to thermal occlusion of end arterioles.5
Patients with AEF present with nonspecific signs and symptoms of fever, fatigue, chest discomfort, dyspnea, dysphagia, nausea, vomiting, odynophagia, hematemesis, and melena—similar to our patient's presentation.1 In one systematic review of 53 case reports of AEF, fever was the most common (n = 44), with second being neurological symptoms (n = 27), and finally hematemesis (n = 19).6 The one-way valve mechanism from the esophagus into the left atrium explains why neurologic events, strokes caused by esophageal debris, and air traveling to the brain are more commonly seen than hematemesis. Patients undergoing upper endoscopy have a significantly higher risk of embolic events even if CO2 is used for insufflation. This is because the force of insufflation opens the valve closing the fistula, allowing a rush of air and esophageal contents to travel into the left atrium. This is the most likely reason why in our patient we only saw blood in the esophagus after insufflating the esophagus. Although CO2 is an inert, noncombustible gas that is rapidly absorbed and is highly soluble in water and blood, there have been case reports of fatal embolic events occurring with CO2 during endoscopy.7 For this reason, endoscopy should be avoided if there is any concern for AEF.1 Patients presenting with sepsis due to AEF also tend to grow Gram-positive organisms in their blood culture, most likely attributed to oral flora, very similar to our patient who had bacteremia with S. mitis.
Diagnosis of AEF is best made with magnetic resonance imaging or CT of the esophagus with oral contrast, which can be seen extravasating from the esophagus into the left atrium.1 In one review of 120 AEF cases, thoracic CT was the most common modality of diagnosis, accounting for 68%, whereas another systematic review of 53 cases identified 51% of diagnosis performed by the same modality.4,6 Similarly, another systematic review found a clear diagnosis of AEF was made in 35% of cases with thoracic CT modality.8 As such, in cases with high suspicion, surgeons sometimes may have to commit to a surgery without a confirmed diagnosis of fistula, especially since early surgical repair is crucial, and the mortality without treatment is 100%.9 There have been reported cases of endoscopic esophageal stent placement for the management of AEF; however, most of these cases have shown much worse outcome than compared with surgical repair.10
In summary, AEF is a rare complication of AF ablation that carries high morbidity and mortality. It is important to be aware of the delayed time frame of patient presentation, presenting signs and symptoms, diagnostic modality, and the best management strategy. If there is any suspicion of AEF, upper endoscopy should be avoided because of the high risk of causing systemic embolization of air, CO2, and oral/gut bacteria, which can lead to serious neurologic deficits and systemic sepsis. Similarly, endoscopic management of AEF leads to significantly poor outcomes and thus should not be attempted.
Author contributions: N. Thapa and Y. Ando wrote the manuscript and reviewed the literature. SW de Melo Jr wrote the manuscript, reviewed the literature, approved the final version, and is the article guarantor.
Financial disclosure: None to report.
Informed consent was obtained for this case report.
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© 2019 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of The American College of Gastroenterology.
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