Findings of the US multicentre cardioneural ablation (CNA) registry were presented during a late-breaking clinical trial session at the Heart Rhythm Society’s 2022 annual meeting (HRS 2022, 29 April–1 May, San Francisco, USA), showing that ablation can be a safe solution to address vasovagal syncope, according to investigators.
The results build on international data around CNA and indicate that the minimally invasive procedure to improve the brain-heart connection is a promising alternative to implanting a permanent pacemaker in young patients, the study’s authors suggest.
Vasovagal syncope is a type of recurrent fainting that occurs when there is a sudden drop in heart rate and blood pressure and can be associated with standing upright for prolonged periods of time, dehydration, stress, or other emotional triggers. Many patients will receive a pacemaker to target slow heartbeats that cause fainting.
CAN is a novel, catheter-based ablation procedure to achieve vagal denervation and was first introduced as a treatment for vasovagal syncope in Brazil in 2004, China in 2012, and Turkey in 2015. This study is the first multicentre trial in the USA to evaluate the feasibility and safety of CNA procedures to treat recurrent fainting spells and slow heart rates.
Between 2016‒2022, 76 CNA procedures were performed in 71 patients across 13 US centres. Patients were treated on a compassionate basis based on their non-responsiveness to medical therapy and/or behavioural modification, and on their desire to not receive permanent pacing. Patients were between the age of 30 and 64 years old. Of the procedures, 63% were performed as concomitant with primary ablation (86% atrial fibrillation/atrial flutter ablation, 7% ventricular tachycardia or premature ventricular contraction, 7% supraventricular tachycardia).
Results showed a low rate of procedural complications with a reasonably high rate of efficacy in patients that received CNA. The majority of patients (82%) remained free from syncope after a single procedure at a median 8.5 months, showing a reduction of median episodes (6 to 0 episodes; p<0.001) after CNA. A sympathetic response during ablation, or an increase in heart rate, (heart rate increase >5 bpm) were observed 70% of cases (SVC-Ao (58%], RAGP [49%], LSGP [19%], LIGP [8%], RA septum [6%], PMLV [2%].
“The benefits of ablation for patients with arrhythmias is well-established, and now we have the potential to apply this modified approach to a young patient population in desperate need of a solution,” said Roderick Tung (University of Arizona College of Medicine, Phoenix, USA), the study’s principal investigator.
“Some patients included had significant head and facial trauma as a result of their sudden fainting episodes. We believe our findings lay the groundwork for new indications for CNA, after seeing the significant impact ablation can make in rebalancing the autonomic nervous system.”
Tung added: “We are encouraged that with a safe, efficient procedure, we may be able to revolutionise how we treat vasovagal patients and patients with functional bradycardia to allow them to resume their everyday lives without the fear and frustration of fainting recurrence.”
Tung was the first cardiologist to report this procedure in the USA and has performed 15 CNA procedures at the University of Chicago and five at the University of Arizona College of Medicine in Phoenix. The authors express that these findings further validate the international data for the use of CNA in vasovagal syncope patients and support a potential expanded indication for catheter ablation for these patients. They also stressed the importance of a prospective registry or randomised trial to further confirm the results and advance this new field and procedure.