An Unusual Cause of Altered Mental Status: Recurrent Cerebral Air Embolism

Abstract

Atrial fibrillation remains the most common cardiac arrhythmia affecting 2.7 to 6.1 million adults in the United States and contributes to significant morbidity and mortality with more than 467,000 annual admissions and more than 99,000 annual deaths. 1,2 Current medical therapy focuses on controlling the rate or restoring sinus rhythm and concurrent anticoagulation with vitamin K antagonist based on risk stratification to decrease the risk of thromboembolic events. Medically refractory cases commonly resort to cardiac ablation to restore sinus rhythm and alleviate symptoms. But cardiac ablation is not a benign procedure and is associated with a 4.5% incidence of major complications and a 0.1% mortality rate. 3,4 Our case demonstrates an unusual but established complication of atrial fibrillation involving atrial-esophageal fistula (AEF) formation and subsequent cerebral air emboli. In a 2010 international survey of radiofrequency ablation procedures, there was a 0.04% rate of AEF formation, 3 and an incidence of 0.1% to 0.9% in patients presenting with sudden neurological symptoms after cardiac ablation. 4 Currently, atrial fibrillation uses the application of radiofrequency energy by transvenous electrodes to cardiac tissue, which leads to irreversible coagulative necrosis and formation of transmural, nonconducting myocardial tissue. 5 Although the high power delivery ensures formation of sufficient lesions, the combination of high power and the anatomical proximity of the esophagus posterior to the left atrial wall increases the risk of complications such as cardiac perforation or AEF formation. Complications from air emboli arise because air in the arterial circulation occludes microcirculation and results in end-organ ischemia. Additionally, oxygen free radicals contribute to more inflammatory changes and edema, leading to worsening damage and neurological deficits not limited to the occluded vascular supply. 5 The AEF can also provide bacterial introduction into the bloodstream with risk for subsequent sepsis. A 69-year-old male with medically refractory atrial fibrillation underwent cardiac ablation for atrial fibrillation with rapid ventricular response. During ablation, temperature did not exceed 28°C, and no events were noted by the cardiologist. The patient tolerated the procedure well and was discharged 2 days following ablation. Nine days after discharge, severe chest pain led to readmission with discovery of an AEF by computed tomography (CT) angiography and subsequent Gastrografin swallow study following surgery recommendations. The AEF was surgically repaired with intercostal muscle flap buttress, and closure confirmed with Gastrografin swallow study. Sixteen days after surgical repair and discharge, the patient developed neurological deficits, including progressively worsening left-sided paresis, hemisensory deficits, and dysarthria. Blood cultures and complete blood count obtained on admission were unconcerning for sepsis. CT and magnetic resonance imaging (MRI)/magnetic resonance angiography re...

Delayed Presentation of Cerebral Air Embolism from a Left Atrial-Esophageal Fistula: A Case Report and Review of the Literature

“…Cerebral air emboli and cardiopulmonary compromise are the main etiologies of these neurologic symptoms [ 2 ]. Oxygen-free radicals promote edema and inflammation, leading to worsening neurological deficits [ 6 ]. Moreover, atrial-esophageal fistula not only introduces air, but also bacteria and food into systemic circulation, resulting in embolization of the brain and multifocal infarcts [ 7 ].…”

“…Administering high-flow supplemental oxygen is also important as it increases the rate of absorption of the embolized air bubbles. Additionally, after supportive therapy and stabilization of the patient, surgical repair of the atrial-esophageal fistula should be undertaken [ 6 ]. Even in patients whose atrial-esophageal fistula was repaired surgically, few survived and many had lasting neurologic deficits.…”