Intermittent reconnection of a pulmonary vein causing multiple tachyarrhythmias: successful identification with ultra-high-density mapping

We present the case of a 59-year-old man with very symptomatic paroxysmal atrial fibrillation (AF) since 2011. The patient had undergone two previous AF ablation procedures: in 2013 with nMARQ™ (Johnson & Johnson Interventional Systems, NJ, USA) and in 2015 with cryoballoon (ArticFront Advance™, Medtronic, MN, USA). He continued with daily episodes of paroxysmal AF, atypical flutter, atrial tachycardia, and atrial extrasystoles with the same P-wave morphology than that of atrial tachycardia, despite treatment with flecainide 100 mg bid. In 2016, we decided to perform a new procedure in order to locate the source of all these atrial arrhythmias with the use of ultra-high-density electroanatomic mapping (RHYTHMIA™, Boston Scientific, MN, USA). First we built, during continuous atrial pacing from the coronary sinus and with an Orion™ catheter, an endocardial voltage map of left atrium (LA) with 11 741 electrograms in 23 min (Figure 1A). The map showed voltage gap images in the anterior aspect of the right superior pulmonary vein (RSPV) and in the superior aspect of the left lateral ridge of a left common trunk (LCT). When the Orion™ catheter was inserted into the RSPV we discovered a regular electrical activity inside the vein with a cycle length of 187 ms dissociated from atrial activity. After ceasing atrial pacing we observed the appearance of monomorphic atrial ectopy, whose frequency increased after isoproterenol infusion. Next we performed an activation map during atrial extrasystole, with 1428 electrograms in 24 min, locating the earliest activation of LA in the RSPV gap (Figure 1B) suggesting an intermittent venoatrial conduction of the activity from the vein. When we ablated the RSPV gap the atrial ectopy disappeared, while the regular activity in the RSPV continued. Then we tried to make an activation map inside the vein, but when we got into the RSPV with the basket Orion(R) catheter the activity suddenly ceased and it was not possible to restart it with isoproterenol or pacing into the vein. We demonstrated the complete isolation of RSPV. Afterwards we could demonstrate by stimulation and activation map that the image of gap in the LCT seen in the voltage map was a false gap image generated by left atrial appendage far-field. The patient was discharged 24 h after the procedure under anticoagulation and a low dose of oral flecainide that was discontinued 3 months later. Two years later, the patient is free of symptoms and recurrence of any atrial tachyarrhythmia in repeated Holter recordings, without requirement of any antiarrhythmic drug. Ultra-high-density mapping is a useful and precise tool to accurate detect and ablate conduction gaps after a first pulmonary vein isolation procedure,1,2 allowing in this case to reach the proper location and isolation of intermittent reconnection of RSPV. Panel (A) Endocardial voltage map of the left atrium. Panel (B) Activation map showing the origin of atrial activation during atrial ectopy in the RSPV gap. This paper was published as part of a supplement supported by a grant by Boston Scientific Italy. Conflict of interest: R.R.-G. has received consultancy fees from Boston Scientific. Other authors declared no conflict of interest.