Background: Autonomic dysfunction resulting from an imbalance between sympathetic and parasympathetic cardiac activity can lead to functional bradycardia due to sinus node dysfunction and atrioventricular nodal block. In case of absence of a structural heart disease and responsiveness to inhibition of the parasympathetic nervous system by anticholinergic agents the main cardiac ganglionated plexi are a potential target for ablation.

 

We hereby report a case of functional bradycardia due to a high grade, symptomatic atrioventricular block in a young 24-year-old female. The patient is an electro technical student and implantation of a pacemaker potentially limits her professional career significantly. After a thorough discussion with the patient we decided to ablate the ganglionated plexi as an alternative to pacemaker implantation offering an individualized treatment approach.

 

Methods and Results: The atria and neighboring great vessels harbor the parasympathetic system in paracardiac fat pads close to the pulmonary veins while sympathetic cells are remote.  For ablation of the ganglionated plexi we used the  cryoballoon technique since it offers a reliable and standard method with very few associated complications. Four cryo-freezes (180 sec, -50°C) in the left atrium covering the ganglionated plexus area using the Medtronic Arctic Front advance cryoballoon ablation catheter were applied. As endpoint we achieved altered autonomic response and gathered data of antegrade, retrograde Wenckebach, and sinus node recovery time. There was a decrease of Wenckebach cycle length (antegrade 400 to 320 ms, retrograde, retrograde 380 to 340 ms) and corrected sinus node recovery time (1710 to 360 ms), respectively.

 

Patient’s recovery and post interventional outcome was uncomplicated and the patient could be discharged from hospital the next day. Post-interventional ECG monitoring showed an increase in heart rate and a reduced heart rate variability without recurrence of AV-nodal block. An implantable event recorder was rejected by the patient, therefore Holter ECGs were scheduled every 2 months for the first 12 months.

 

Conclusion: Cardio neuroablation using the cryoballoon technique is a promising method to treat disorders of increased cardiac parasympathetic activity. Due to a lack of standardized approaches and concomitant evidence at this point cardio neuroablation must be considered as individual treatment option solely.