Autonomic Modulation
Cardioneuroablation
Cardioneuroablation is a catheter technique that targets small clusters of nerve tissue on the heart surface that influence heart rate. It is being used in selected patients with severe, recurrent reflex syncope or certain functional slow rhythms.
On this page
The Concept
What Is Cardioneuroablation?
The heart rate is modulated by the autonomic nervous system. Near the surface of the atria lie clusters of nerve cells called ganglionated plexi. In reflex syncope and some forms of functional bradycardia, excessive vagal activity can slow the heart or cause pauses.
Cardioneuroablation uses catheter-based radiofrequency energy to modify these nerve clusters and reduce the vagal influence. Unlike conventional ablation, the target is not a circuit but the autonomic input to the heart.
The technique is relatively new, and the evidence base is still developing, so patient selection is careful and expectations are balanced.
Mechanism
Cardioinhibitory Reflex Syncope
In vasovagal syncope a reflex can slow the heart (a cardioinhibitory response), lower the blood pressure (a vasodepressor response), or both. Cardioneuroablation targets the heart-rate part of the reflex. People whose faints are mainly due to a fall in blood pressure without marked slowing may be less likely to benefit.
Documenting the pattern helps to decide whether the reflex is mainly cardioinhibitory. This may involve rhythm recordings during symptoms, an implantable loop recorder in selected people (see Event Recorder) or tilt-table testing. See Vasovagal Syncope.
Patient Selection
Who Might Be Considered?
Recurrent vasovagal syncope
Patients who faint repeatedly and unpredictably, despite simple measures, particularly when the heart rate drops markedly during an episode.
Functional bradycardia or pauses
Selected patients in whom slow rates or pauses are due to high vagal tone rather than disease of the conduction system.
Younger patients who wish to avoid a pacemaker
In whom a device is a less attractive option, after a full discussion of alternatives.
It is generally not intended for people with fixed conduction disease or for whom the cause of fainting has not been properly established.
Assessment
Establishing the Diagnosis First
History and examination
Detailed description of faints, triggers and medicines.
Documents pauses or slowing during symptoms.
Tilt-table testing
Used in selected patients to document the reflex pattern.
Echocardiography
Excludes structural heart disease as a cause.
Shared decision
Alternatives, including observation, medication and pacing, are discussed.
The Procedure
How It Is Performed
Catheters are placed through veins, usually at the groin. 3D electroanatomical mapping is used to identify the regions where the plexi lie, using anatomical and electrical criteria, and energy is delivered in a planned pattern.
The procedure is usually carried out under sedation or general anaesthesia, depending on the centre and the patient.
A rise in resting heart rate after treatment is expected and may last for a time.
Methods of identifying targets and of defining the end point differ between centres, which is why experience with the technique is important.
Evidence
Evidence Status
Evidence consists mainly of observational studies and a small number of randomised trials, with differing techniques, targets and follow-up periods. Results cannot be applied to every patient. The treatment is generally regarded as an emerging option and is not a routine, guideline-established therapy for reflex syncope.
For this reason the procedure is discussed openly, including the possibility that symptoms return, and is reserved for people in whom simpler measures and alternatives have been considered. It should not be seen as routine or as suitable for everyone with fainting.
Expectations
Possible Benefits, Limits and Risks
Possible benefit
Fewer or no syncope episodes in some patients, and avoidance of a pacemaker in selected cases.
Limits
Long-term durability is still being studied. Parasympathetic activity can partially recover and symptoms can return.
Risks
Include those of any left- or right-atrial catheter ablation, such as vascular complications, and rarely injury to nearby structures. A higher resting heart rate may occur.
Cardioneuroablation is not suitable for every patient with fainting. Your cardiologist will advise whether it fits your situation.
After treatment
Follow-Up After Cardioneuroablation
Heart-rate changes
A rise in resting heart rate is expected and may be noticeable. Your team explains what to expect and when to report symptoms.
Symptom record
Keeping a record of any faints or near-faints, with rhythm monitoring where advised, helps the team judge the effect of treatment.
If symptoms return
A new assessment clarifies whether a repeat procedure, another measure or pacing is appropriate.
Everyday measures
Recognising warning signs and using counter-manoeuvres remain useful alongside treatment.
Questions
Frequently Asked Questions
Is cardioneuroablation a cure for fainting?
Is it an alternative to a pacemaker?
Will my resting heart rate change?
Can it be repeated?
Continue reading