Cardioneuroablation (CNA) is a specialized catheter procedure that addresses certain heart rhythm disturbances by modifying the nerves that regulate the heart. Unlike ablations targeting heart muscle, this technique focuses on nerve cell clusters within the autonomic nervous system. This system controls involuntary functions like heart rate and blood pressure.
The procedure aims to recalibrate an imbalance in the nervous system signals sent to the heart. By disrupting overactive nerve pathways, particularly those of the vagus nerve, cardioneuroablation helps stabilize heart function. This approach treats the source of the irregular signals rather than the heart’s reaction to them.
Medical Conditions Treated
Cardioneuroablation is used to treat conditions caused by an overactive parasympathetic nervous system, which can excessively slow the heart rate. The most common is vasovagal syncope, a condition characterized by fainting spells. These episodes occur when a trigger causes a sudden drop in heart rate and blood pressure, reducing blood flow to the brain and causing a temporary loss of consciousness.
Another application is for certain types of bradyarrhythmias, or abnormally slow heart rhythms. This includes functional atrioventricular (AV) block, where the electrical signal coordinating heartbeats is blocked due to excessive vagal nerve activity. This condition is not caused by a structural problem within the heart’s conduction system.
For many patients, especially younger individuals, this procedure is an alternative to a permanent pacemaker. Pacemakers are effective but can present long-term challenges for active people. Cardioneuroablation seeks to restore a normal heart rhythm without an implanted device by targeting the root cause of the nerve response.
The Ablation Procedure Explained
The cardioneuroablation procedure is a minimally invasive technique performed in a cardiac catheterization or electrophysiology lab. Patients fast for several hours beforehand and are placed under sedation or general anesthesia to ensure comfort. An electrophysiologist begins by inserting thin, flexible tubes called catheters into a blood vessel, usually in the groin area.
Using advanced imaging for guidance, these catheters are carefully threaded through the vascular system to the heart’s chambers. Once in position, the primary task is to create a detailed map of the heart’s intrinsic nervous system. This involves identifying the precise locations of the ganglionated plexi—small clusters of nerve cells on the heart’s surface that transmit vagal signals.
To locate these nerve bundles, electrophysiologists use high-frequency stimulation to observe the heart’s response. When stimulation at a certain point causes a significant slowing of the heart rate, it confirms a target ganglion. After these sites are mapped, the ablation catheter delivers radiofrequency energy, a low-voltage, high-frequency current that generates heat.
This energy creates small, precise lesions on the targeted nerve tissue, modifying it so it can no longer transmit disruptive signals. The electrophysiologist targets several of these ganglionated plexi, which are found in specific anatomical regions of the left and right atria. The entire process generally takes between one and two hours.
Determining Patient Suitability
Deciding if a patient is a suitable candidate for cardioneuroablation involves a thorough evaluation to confirm symptoms are caused by excessive vagal nerve activity. This procedure is reserved for individuals with severe and recurrent symptoms who have not found relief with first-line treatments like lifestyle adjustments or medication. The ideal candidate has a structurally normal heart, meaning the problem lies with the nervous system’s control over the heart, not the organ itself.
A series of diagnostic tests is used to pinpoint the cause of the symptoms. A head-up tilt-table test is a common tool to diagnose vasovagal syncope. During this test, the patient is secured to a table that is tilted upward, simulating a change in posture which can trigger the abnormal reflex. A positive test that reproduces fainting with a significant drop in heart rate suggests a patient may benefit.
Prolonged heart monitoring, with a Holter monitor for 24-48 hours or an implantable loop recorder for long-term tracking, is used to document episodes of bradycardia or asystole. Additionally, an atropine test may be administered. Atropine is a medication that blocks the vagus nerve’s effects, and a significant increase in heart rate after its administration indicates a high vagal tone and predicts a favorable response.
Post-Procedure Recovery and Outlook
Following a cardioneuroablation procedure, patients are monitored for several hours as the sedation wears off. An electrocardiogram (ECG) is often performed to confirm the treatment’s effect on the heart’s rhythm. A hospital stay of one night is common, though some patients may return home the same day. Bruising and mild discomfort at the catheter insertion site are typical and resolve within a few days.
Activity is generally restricted for a short period. Patients are advised to avoid strenuous exercise and heavy lifting for one to two weeks to allow the insertion site to heal completely. Most people can return to work and normal daily activities within a few days.
The long-term outlook for patients undergoing cardioneuroablation is positive. Studies show a significant reduction or complete elimination of fainting spells and other symptoms in most patients. While nerve tissue can sometimes regenerate, many patients experience lasting relief. Follow-up appointments with a cardiologist are scheduled to monitor heart rhythm and overall progress.