Minimally Invasive AF Ablation Surgery

The Convergent Treatment Strategy for AF
The Convergent procedure is a hybrid approach involving collaboration between a cardiac electrophysiologist and a cardiac surgeon.

The goal of the procedure is to return your heart back to normal sinus rhythm. The procedure is called hybrid as it is a collaboration between a specialist Electrophysiologist (EP) and Cardiac surgeon. EP leads the team to identify appropriate candidates who will benefit from the procedure.

The procedure has two stages. The first stage is minimal invasive surgery which is performed by the cardiac surgeon and the second stage is mapping and catheter ablation performed by EP.

The aim of the procedure is to ablate areas of the heart which are considered to be the source of AF. Radiofrequency is used as an energy to ablate, and create scar tissue in the focused area of the heart to ablate/interrupt AF circuits without causing any significant long-term side effects.

The Convergent treatment has an established track record with over 9000 procedures performed in the US and Europe.

Who is considered and why?
In the vast majority of patients with paroxysmal AF and a structurally normal heart, catheter ablation using radiofrequency energy (focused heat) only targeting the pulmonary veins (Pulmonary Vein Isolation or PVI) will provide an excellent suppression of AF. This is done by a cardiologist (cardiac electrophysiologist) and in most cases only requires an overnight stay in hospital. When this is successful the patient experiences an improvement in quality of life as a result of symptom control and avoids the need for anti-arrhythmic medication.

Convergent is considered when we suspect that AF is being initiated and maintained by diseased areas outside of the pulmonary veins. Most patients considered for Convergent will have persistent AF (AF that lasts continuously for more than 7 days) or will have failed previous attempts at PVI procedures. An electrophysiologist who has experience with Convergent identifies patients who are likely to benefit from the hybrid procedure. These patients generally represent the ‘difficult end of the spectrum of AF’ usually because they have AF sources separate or distant from the pulmonary veins. Not all patients who have persistent AF are candidates for this procedure.

What is the difference with catheter ablation?
Convergent is a significantly more aggressive ablation strategy than standard catheter ablation. It requires a close collaboration between two medical specialists and their respective teams; A cardiothoracic surgeon and a cardiac electrophysiologist. The surgeon will perform the surgical ablation which is the first part of the treatment and then six months later the cardiac electrophysiologist will perform a catheter mapping and ablation procedure accessing the heart using catheters inserted at the right groin.

Fundamentally, cardiothoracic surgeons are able to perform minimally invasive ‘thoracoscopic’ procedures from the outside of the heart, while cardiac electrophysiologists perform minimally invasive procedures using catheters placed within the heart itself. This approach allows for maximum ablation of the posterior left atrial wall resulting in debulking of AF sources.

The surgeon performs a thoracoscopic surgical ablation which requires the use of a specially engineered ablation tool and delivery system. Thoracoscopic surgical ablation is performed on the beating heart with small incisions rather than entirely opening the chest wall and stopping the heart from beating. This significantly reduces the risk, and results in a more rapid recovery than open heart surgery.

The surgical ablation tool has a much larger working surface than an ablation catheter and, using the same radiofrequency energy as catheter ablation, efficiently ablates a greater surface area of atrial tissue. In addition, the latest design of surgical tools allows for the radiofrequency energy to be directed only to the focused area of the heart while protecting the structures around it. This design helps prevent injury to the oesophagus (food pipe) which is highly sensitive to heat. This avoids a nasty complication called atrial esophageal fistula.

During the Convergent procedure and immediately after the surgical ablation, an additional procedure is performed to occlude and isolate the left atrial appendage. The left atrial appendage is a little pouch originating from the left atrium. It is thought to be the source of 90% of clots in patients with atrial fibrillation increasing the risk of stroke. Your left atrial appendage will be occluded with a device known as Atriclip PRO2. This serves two important functions:

  1. Stroke reduction – the majority of blood clots (>95%) leading to AF strokes originate from the left atrial appendage
  2. AF reduction – the appendage muscle tissue becomes strangulated because the pressure of the AtriClip blocks the nourishing blood flow and eventually the tissue beyond the Atriclip dies. This removes another potential non-pulmonary vein electrical source of AF as the left atrial appendage is a well recognised secondary source of AF triggers.

Each patient has different anatomy and some areas of the left atrium cannot be reached during the surgical part of the procedure. For this reason at 2-3 months post-surgery, the cardiac electrophysiologist will perform an extensive electrical mapping and ‘touch up ablation’ of the left atrium using specialised mapping tools and 3 dimensional electrical mapping. The pulmonary veins are also checked and re-ablated if necessary during this second component.

Before your surgical procedure

Patients will have separate appointments with the cardiologist/cardiac electrophysiologist and surgeon to assess their suitability to undergo this procedure. Work-up for the procedure involves a number of tests including but not limited to: to blood tests, a chest X-ray, and a cardiac CT scan.
After your outpatient review with the surgeon, you will be given information about the admission process. You will be reviewed by a nurse in a preadmission clinic. Some blood tests will be performed in preparation for the procedure. Generally, you will be admitted to hospital the night before your procedure. The patient will have the opportunity to speak with the cardiac anaesthetist prior to the procedure. Specific instructions for preparations for this procedure may include temporarily withholding medications, fasting, and using a special soap to shower.

Anticoagulant (blood thinner) medication :
You will be asked to stop your anticoagulation medication 48 hours prior to the procedure. You must discuss this with the surgeon prior to the procedure. Failure to stop these medications may result in cancellation of the procedure due to increased risk of bleeding.

What happens on the day of admission for surgical procedure ?
The patient will be admitted to hospital the night before the procedure and will be asked to change into a surgical gown in preparation for the procedure. Nurses and hospital staff will ask about the patients’ health history and medications and an ECG and blood tests will be performed. Body hair may be clipped. All your blood results and reports will be reviewed. Any of the pending tests may be completed during the day. Your anaesthetist will meet with you to discuss the anaesthetic part and management of postoperative pain. Please discuss any concerns you have regarding anaesthesia or pre-procedure anxiety.

The surgeon may visit you during the day in case you have any queries.

On the day of your surgical ablation procedure

During the surgical ablation procedure, the patient will be under a general anaesthetic administered by a cardiac anaesthetist. The patient will be administered an anaesthetic using an IV line. After the patient is under anaesthesia, a urinary catheter and other monitoring lines are inserted. The anaesthetist will perform a transesophageal echocardiogram (TOE) to check for blood clots in the heart. The procedure will be abandoned if any clots are located in the heart.

The surgeon will then make a small incision. He will then use a telescope guided radiofrequency tool, to create scar tissue on the outside of the back wall of the left atrium that will destroy the irregular electrical pathways. Your heart will NOT stop beating during this procedure. The surgical part of the procedure lasts 2 to 3 hours. A small drain will be placed in the cavity outside the heart.

After the surgical ablation, the surgeon will also place the Atriclip device on the left atrial appendage to occlude it using 3 small incisions (1-1.5cm) placed on the left side of the chest. This usually takes less than 30 minutes.
The patient will be awake after the procedure.

After your surgical procedure
Once the procedure is complete the patient will be returned to the cardiac surgery ward for 2-3 more days. During this time, the heart will be carefully monitored. Heart rate, heart rhythm, blood pressure, and oxygen level will be continuously monitored. A tube will be used to drain fluid from outside the heart and will be removed 6-24 hours post-op. An IV line will administer fluids and medication will be prescribed to manage the pain. Please ask for additional pain killers if you are experiencing pain. Nurses will assess your pain on a scale of 1 to 10 and administer analgesics.

The day following the procedure your nursing team will help you sit in a chair and also walk in the corridor. This will help you recover from surgery.

The surgeon will talk to you about the procedure on the following day and you can discuss any questions you have.

At this stage your heart rhythm may be regular but don’t be surprised/disappointed if you are still in AF.

On the day of discharge:
A night prior you will be notified of your discharge time and date. You will have a dressing in the front of your chest which can be removed by yourself or your GP after 2 weeks. You will go home with 2 stitches on the left side of your chest which will be removed by your GP after 5 days.

You will be given a list of medications. You will also be given a request for an echocardiogram to be undertaken in 2 weeks and cardiac CT in 4 weeks. You need to organise an appointment to see your cardiologist/electrophysiologist in their rooms 2-3 weeks after the procedure. The surgeon will see you for follow-up after 4 weeks.

Post discharge care:
Do not put any ointment or creams on wounds. If you have any unusual pain or redness, please visit your GP and also notify the surgeon.

Do take a shower. You can discuss with the nurse prior to discharge about care to be taken during the shower. Please do not go swimming or in the bath tub for 2-3 weeks until wounds are completely healed.

Stay active at home. Take rest in between activities. It is not uncommon to feel tired easily but you should see gradual improvement in your stamina. Avoid lifting more than 5 kg for 3 weeks following the procedure

Fortunately, they are uncommon given the nature of the procedure. The most relevant complications are:

Cardiac perforation or injury – any procedure on the heart has this risk. It is quite an uncommon complication. However, the management of this requires sternotomy (breastbone incision) and repair of injury. Since the first stage of procedure is done by a heart surgeon, they are very capable of dealing with such complications in the event it occurs

Pericarditis – Pericardium is a sac around the heart. To gain access to the heart the surgeon will incise the sac. The instruments and catheter used during the procedure rubs against the sac. This and other aspects of the procedure leads to inflammation of the sac which is called “ pericarditis” ie. Inflammation of pericardium. Your team will already implement a preventative strategy to minimise this problem. These complications can manifest as pain, fever or fluid build up in the sac.

Stroke – Although very rare it is worth a mention. It can result during or after the procedure due to formation of small clots in the atrium. You will get an intraoperative tranoesophageal echocardiogram to assess and confirm the absence of any clots prior to proceeding with the procedure. After surgery, you will be commenced on blood thinners to prevent clot formation in the heart.

Pericardial effusion – this is the fluid build-up around the heart. This can occur secondary to inflammation of pericardium. Depending on its size we may observe it or aspirate it with a needle. This can occur after you are discharged. It can cause shortness of breath, fever, flu like symptoms, sweats or fast heartbeat. Please contact your cardiologist if you experience any of these symptoms.

Incisional hernia – some patients may experience gapping under the incision. This may lead to abdominal structure like the intestine to migrate under the skin incision intermittently (hernia). Please consult your surgeon if you notice such a development.

You will be reviewed by the surgeon in the clinic after 4 weeks with chest x ray and cardiac CT. At this visit you will get a chance to discuss any question or results of the procedure. You will be discharged from the clinic if there are no ongoing issues.

You should get an appointment with your Cardiologist after your procedure with the first appointment at 1 month post-surgery. At each visit you will have an ECG to determine whether or not you are in sinus rhythm. It is normal to require a DC cardioversion within the first few visits. Your cardiologist will organise a holter monitor to assess your rhythm at regular intervals.

A DC cardioversion uses an electric shock to literally shock the heart back into rhythm. This is performed under a brief (minutes) general anaesthetic and the patient is discharged 2 hours later.

At six months post surgical ablation the cardiologist will book your mapping and ablation procedure.

Comparatively this procedure is significantly less invasive than the surgery and is done to document completeness of the surgical ablation with some additional ‘touch up’ ablation from within the heart to complete the posterior wall ablation. The pulmonary veins are also checked and ablated if necessary during this second component.

The success rate of the Convergent procedure is highly dependent on individual patient circumstances. We know that patients with AF can significantly improve their success rate of any AF intervention by maintaining a healthy weight by diet and exercise, addressing sleep apnoea if it is present, managing any coronary disease aggressively and keeping blood pressure and blood sugar within tight control.

As a general guide, we expect a minimum success rate of 70% for any patient being considered for this treatment. Some patients have clinical features that suggest a poor outcome and they will not be considered for the hybrid approach. Importantly, the surgical component cannot be repeated due to the formation of scar tissue. Patients can have repeated catheter ablation following Convergent if required.

Associate Professor Pragnesh Joshi trained for HyCASA ablation in the USA during supervised intensive training in November 2018 and now works in close clinical collaboration with specialist cardiac electrophysiologists for patients offered this treatment strategy.