Cryoablation, Antalya | Prof. Dr. Umuttan Doğan

Cryoablation puts the heart tissue causing a rhythm disorder out of action by freezing it rather than heating it. It is also spoken of as cold ablation. Its commonest use is in atrial fibrillation: a balloon-shaped catheter is seated at the mouth of a vein coming from the lungs and freezing creates a ring of isolation in one go. Whether it suits you depends largely on the anatomy of those veins.

What Is Cryoablation?

The aim of ablation is the same whatever the method: to take away the ability of the tissue that starts or sustains a rhythm disorder to conduct.

In cold ablation, as the name says, that is done with cold. A liquefied gas is fed into the balloon at the tip of the catheter; as it expands inside the balloon it draws heat from its surroundings and the surface of the balloon falls to a very low temperature. The tissue it touches freezes.

How Does Cold Affect the Tissue?

As it freezes, ice crystals form inside and around the cells. They disrupt the structure of the cell, and the cell loses its function.

There is a practical detail here: once freezing begins, the balloon sticks to the tissue. That holds the catheter steady and stops it slipping during the procedure. With methods such as radiofrequency, keeping the catheter still is a job in itself.

Why a Balloon?

The core of atrial fibrillation ablation is creating an unbroken line around the openings where the veins from the lungs enter the left atrium. This is called pulmonary vein isolation.

With radiofrequency that line is drawn point by point; the cardiologist completes the circle by moving the catheter along one step at a time. If one of the points is missed, a gap is left in the line.

With a cryoballoon, the balloon sits at the mouth of the vein and seals it. Once freezing begins, the whole circumference in contact is treated at the same moment; the ring is made in one go.

This is why cryoablation is spoken of as a single-shot method, and the procedure often runs more predictably. In return it is less flexible: the balloon can only seat at a round opening and cannot draw a free line within the atrium.

Who Is Cryoablation For?

Patients with atrial fibrillation whose palpitations and symptoms continue despite medication
Those who cannot take rhythm medicines because of side effects
People whose AF comes in episodes and for whom rhythm control is the goal
Patients whose pulmonary vein anatomy suits a balloon

Is the Anatomy Suitable?

This section covers what decides a cryoablation, and most other sources do not include it.

Normally four separate veins open into the left atrium. For the balloon to do its work, each opening has to be round and of a size the balloon can seat in properly.

Anatomy is not the same in everyone, though. In some people two veins open through a single shared opening, which can be too wide for the balloon to seal. In others there is an additional vein.

The anatomy of the left atrium and the veins is therefore assessed with a CT scan beforehand. Where it is not suitable, radiofrequency or PFA is preferred.

When It May Not Be Suitable

Where there is a clot in the left atrium; the procedure is postponed
Where the openings of the veins are not shaped to suit a balloon
Advanced atrial fibrillation needing extra lines within the atrium
Where an ablation has been done before and the point to be isolated again calls for point-by-point work
Where there is a correctable cause behind the rhythm disorder

Is Cryoablation Used Outside Atrial Fibrillation?

Yes. Cold ablation has a characteristic of its own that brings it to the fore in some rhythm disorders other than atrial fibrillation.

A Reversible Trial: What Only Cold Can Do

Some sources of palpitations sit right beside the heart’s natural conduction pathway. Delivering energy there carries a risk: damage to that pathway can mean a permanent pacemaker.

With radiofrequency the effect is permanent the moment the energy is delivered; there is no going back.

Cryoablation has an intermediate step. The tissue is first cooled without going all the way down to freezing. At that milder cold the cells stop conducting for a time, but their structure is not damaged.

That lets the cardiologist run a trial: have the palpitations stopped, and has the conduction pathway been affected? If the answer is what was wanted, the freezing is taken to full strength and the effect becomes permanent. If an unwanted change is seen in the conduction pathway, the cooling is stopped, the tissue warms and its function returns.

This “try it first, then make it permanent” option exists only with cold energy. It is why cryoablation is considered particularly for sources very close to the conduction pathway, and in younger patients.

How Is the Procedure Carried Out?

It goes in through the vein in the groin. The catheters first reach the right atrium; to get to the left atrium, a controlled crossing is made through the thin wall that separates the two.

The balloon is placed at the mouth of the vein. That the opening is fully sealed is confirmed by injecting contrast dye: if none leaks back, the contact is complete. Freezing then begins.

A freezing cycle is applied for each vein, and at the end the isolation is measured to confirm that it is complete. This confirming step is not skipped.

How Is the Phrenic Nerve Protected?

This is the most characteristic concern with cryoballoon ablation, and the way it is guarded against is surprisingly simple.

The phrenic nerve, which drives the diaphragm, runs just beside the veins on the right side. If the freezing reaches that nerve, the diaphragm can weaken temporarily.

To prevent it, the phrenic nerve is stimulated continuously with a separate catheter while the right side is being frozen. The diaphragm contracts with each impulse, and the cardiologist places a hand on the abdomen and feels that contraction. If it begins to weaken, the freezing is stopped there and then.

The nerve is protected, in other words, not by an advanced device but by that simple check kept up throughout. Any weakness that does develop is usually temporary and recovers in time.

What Will You Feel?

Cold has a numbing effect of its own. Cryoablation is therefore less uncomfortable than radiofrequency, and local anaesthetic with sedation is enough for most patients.

While the freezing is under way you may feel coldness or mild pressure in the chest. Do tell the team if you are uncomfortable.

How Long Does It Take?

It would not be right to give a firm figure. The number of veins, how easily the balloon seats and whether extra freezing is needed all decide it. Because the balloon makes the ring in one go, the procedure runs to a predictable pattern in most patients. Your observation afterwards is the same as the standard follow-up after such a procedure.

How Cryoablation, Radiofrequency and PFA Differ

Radiofrequency: heat, working point by point. Flexible, which suits cases needing extra lines within the atrium.
Cryoablation: cold, making the ring in one go. It runs predictably but needs an anatomy the balloon can seat in.
PFA: non-thermal energy, short electrical pulses. Its defining feature is selectivity for the tissue.

There is no order of superiority among the three that holds for every patient. The choice follows the structure of the atrium and the veins, how long the atrial fibrillation has been going on, whether an ablation has been done before, and the equipment available.

How Do You Prepare?

Checking for clot: shortly before the procedure, the left atrium is assessed with imaging for clot. If there is one, the procedure is postponed.
CT scan: the anatomy of the veins is examined beforehand; the size of balloon and the plan follow from it.
Your list of medicines: bring everything you take, with the doses. You may be asked to stop some rhythm medicines; that decision is your doctor’s.
Blood thinners: your doctor decides how they are managed around the procedure; do not stop them on your own.
Your rhythm recordings: bring any ECG and Holter recordings made during your palpitations.

At the consultation beforehand the expected benefit, the possible risks and the alternative methods are explained, and your written consent is taken.

What Are the Possible Risks?

Temporary effects on the phrenic nerve. This is the best known concern with a cryoballoon; it is monitored throughout, and where it does develop it usually recovers in time.
Bruising, bleeding or injury to the vessel at the access site
A small opening left in the wall that was crossed; it usually closes by itself, though in some patients it stays open for a long time and is monitored
Fluid collecting in the sac around the heart; rare, and drained if needed
Narrowing at the mouth of a vein
The rhythm disorder returning in time, with a second procedure needed

The risks are weighed against the benefit expected from the procedure and discussed in detail for your own situation at the consultation beforehand.

Afterwards

Pressure is applied at the access site in the groin and bed rest is advised for a period.
The first three months are the blanking period; episodes of palpitations during it are to be expected and do not mean the procedure has failed.
Blood-thinning treatment is followed for the period your doctor sets. That period follows your risk of stroke, not the result of the ablation.
Your rhythm medicines may be continued for a while; whether they are stopped is your doctor’s decision.
Weight, sleep apnoea, alcohol and blood pressure all affect the result directly.
Cardiology review is carried out at set intervals, with rhythm recordings if needed.

If you notice palpitations that go on for a long time, worsening breathlessness or marked swelling at the access site, see your doctor without waiting.

Cryoablation in Antalya

Prof. Dr. Umuttan Doğan is a cardiologist who trained in electrophysiology at the Gülhane Military Medical Academy in 2012; ablation of rhythm disorders using radiofrequency, cryoballoon and PFA energy is one of the areas he works in. The procedures are carried out in the catheter laboratory at Antalya American Hospital.

If you have palpitations, or ablation has been suggested to you, you can be seen at the clinic in Konyaaltı with your ECG and Holter recordings. For atrial fibrillation as a whole see AF ablation, and for the other procedures the rhythm disorders and ablation page. You will find his background and contact details on their own pages.

Frequently Asked Questions

Does freezing harm the heart?

The aim is precisely to take away the conducting ability of a small, targeted area of tissue, and that is done in a controlled way. Cold acts over the limited area it touches. The possibility of unwanted effects on neighbouring structures is monitored throughout; watching the phrenic nerve while the right side is frozen is the clearest example.

Which is better, cryoablation or radiofrequency?

There is no order of superiority that holds for every patient. Where the openings of the veins suit a balloon, cryoablation runs predictably. Where extra lines are needed within the atrium, or the anatomy does not suit a balloon, radiofrequency is more flexible. The decision follows your own anatomy.

Is the procedure painful? Will I be awake?

Because cold has a numbing effect of its own, cryoablation is generally less uncomfortable, and local anaesthetic with sedation is enough for most patients. You may feel coldness or mild pressure in the chest while the freezing is under way.

Can cryoablation be done in every patient?

No. The balloon has to seat properly at the mouth of the vein. In some people two veins open through a single wide shared opening, or there is an additional vein. The anatomy is therefore assessed with a CT scan beforehand; where it does not suit, another form of energy is chosen.

What happens if my palpitations carry on after the procedure?

The first three months are called the blanking period, and episodes during it are to be expected; while the treated tissue heals it stays excitable for a while longer. No judgement is made before the three months are up. It helps to record those episodes and show them to your doctor at your review.

The information on this page is for general guidance and does not replace a consultation. Decisions about diagnosis and treatment are made by your doctor after assessing your own situation.