Successful bail-out of a massive air embolism during catheter ablation for atrial fibrillation

Catheter ablation is an effective treatment for atrial fibrillation (AF). With the evolution of catheters, the incidence of periprocedural complications has decreased. Air embolisms are a severe and sometimes life-threatening complication. We experienced a case involving the successful bail-out—without any residual neurological disability—of a massive air embolism filling the ascending aorta and right coronary artery during radiofrequency catheter ablation of AF.

A man in his 60s with hypertension developed dyspnea on exercise and was diagnosed with persistent AF. He was started on edoxaban (60 mg, once daily). His body mass index was 24.5 kg/m². No sleep apnea syndrome had been pointed out. A family doctor referred him to our hospital for catheter ablation of AF.

One day before the ablation procedure, transesophageal echocardiography confirmed the absence of left atrial appendage thrombus. On the day of the ablation procedure, the patient presented in AF with an average heart rate of 58 beats/min. The procedure was performed under deep sedation using propofol and flunitrazepam with the assistance of adaptive servo-ventilation (ASV). The procedure was consistently performed in the supine position. After obtaining right femoral venous access (9F and 2 8F long SL0 sheaths [Abbott, St. Paul, MN] in the right femoral vein), heparin was administered to maintain an activated clotting time of 300–350 seconds. A single transseptal puncture was performed using intracardiac echocardiographic and fluoroscopic guidance. AF was restored to sinus rhythm after defibrillation with 150 J. Under sinus rhythm, each pulmonary vein was successfully isolated by a radiofrequency catheter (Tacti Catheter SE D-D; Abbott). The cavotricuspid isthmus line was ablated, and a bidirectional block was confirmed. The SL0 sheath was replaced in the left atrium (LA) by a deflectable sheath (Agilis; Abbott) for LA linear ablation. After that, the patient suddenly became agitated, hypotensive, and bradycardic with ST elevation of II, III, and aVF on a 12-lead electrocardiogram. Intracardiac echography revealed no epicardial effusion; however, left ventricular inferior wall hypokinesis was observed. Subsequently, cardiac arrest occurred, and emergency coronary angiography under pacing (pacing cycle length = 600 ms) from the right ventricular apex was performed. Fluoroscopy showed a translucent right coronary artery (RCA) (Figure 1A and 1B ), which indicated that the RCA was entirely embolized by a large amount of air. The patient’s head was held down to avoid raising it above the horizontal level. An aspiration catheter (Thrombuster 7Fr GR; Kaneka Medical, Tokyo, Japan) was used to aspirate a large amount of air; the coronary angiography revealed residual air in the RCA (Figure 1C), and a smaller aspiration catheter (Thrombuster 6Fr GR; Kaneka Medical) was used to attempt aspiration from the distal RCA and to inject nitroprusside hydrate. The air in the RCA was removed entirely by further washout with saline, and the ST elevation improved (Figure 1D). At this point, air retention was suspected in the anterior portion of the ascending aorta (between the aortic root and arch, which is the highest level in the supine position). A 5F pig-tail catheter and a 5F Judkins Right (JR4) catheter were inserted from the femoral artery to aspirate air in the ascending aorta. Then, the air in the ascending aorta appeared to be entirely removed. Further ablation procedures ceased. The patient was admitted to the coronary care unit ward.

After the procedure, his consciousness rapidly recovered. A certified neurologist performed a systematic clinical neurological examination and noted no abnormal neurological findings. Diffusion-weighted magnetic resonance imaging showed a small high-intensity area (2.0 × 2.2 mm) in the right corona radiata that was suspicious for acute cerebral infarction. No residual air was observed on cerebral, chest, or abdominal computed tomography. The peak creatine kinase (CK) and CK-MB levels were 355 U/L (normal levels 59–248 U/L) and 32 U/L (normal levels 0–5 U/L), respectively, and he was discharged without a residual disability on the fourth postoperative day. The patient had a recurrence of AF 1 year later, underwent repeat ablation, and remained AF-free.

We experienced a case of massive air embolism of the RCA and ascending aorta during RF catheter ablation for persistent AF in which emergency catheter treatment rescued the patient without any residual disability.