Surgery for Ablation of Atrial Fibrillation

 

What is atrial fibrillation (AF)?

The heart beats at regular intervals and is able to beat faster when required to pump more blood in the body if required while exercising,or during increased level of activity. The heart has two sides and four chambers. They need to synchronise to be able to receive blood in and pump it out. Thinner chambers of the heart are collecting chambers and are known as “Atrium”.  Both the right and left atrium collect blood and empty that into thicker, more muscular chambers known as “ventricles”. Ventricles pump blood out of the heart. It is obvious that both the atrium and ventricles need to beat in synchrony to be able to function properly. This normal synchronised rhythm is known as “ sinus rhythm “

There are various types of rhythm abnormalities but the term atrial fibrillation applies to the rhythm that results from propagation of disorganised electrical impulse that spreads from the atria to the rest of the heart. Normal “sinus rhythm” is generated by an electrical impulse generated by the main electrical power house of the heart known as the “sinus node”. In atrial fibrillation the impulses of the sinus node are masked by disorganized electrical impulses generated by abnormal areas in both atria. The left atrium is more affected than the right in atrial fibrillation. In atrial fibrillation, there is a random, disorganised electrical impulse firing,leading to random and disorganised beating of the heart,which is most commonly experienced as random fast heart beat or pounding heart. Patients may experience dizziness, blackouts , tiredness, shortness of breath or lack of energy. Some patients will not experience any symptoms at all.

Atrial fibrillation can occur on its own or may be associated with other heart disease.

What are the side effects of atrial fibrillation?

There are other more dangerous heart rhythms than AF. AF can cause the following complications

  1. Stroke
  2. Heart failure
  3. Heart valve malfunction – leakage

Types of AF

Paroxysmal AF: Simply put this type of AF is on and off with or without the use of medication. This type responds to medical therapy and catheter ablation(via groin puncture) and yields very good long term results

Persistent AF: Simply put this type is a complex one which is resistant to medical therapy or catheter ablation. Patients with this type are in AF continuously or for longer periods with or without therapy. In general, catheter ablation has a lower success rate and multiple procedures are necessary to improve the success rate.

What are the treatment options for correction of AF?

There are three options:

  • Medical therapy
  • Catheter ablation
  • Surgical ablation

Lets understand what works for whom

Medical therapy : is not very effective and hence not popular. This is because of its lower success rate and significant side effects of medications. Anti AF medications have quite a few toxic side effects and some of them require monitoring. So, generally medical therapy is reserved for patients who have very few symptoms or are a not candidate for invasive therapy

Catheter ablation : is a very effective method of controlling and correcting AF when AF is occurring in episodes(Paroxysmal AF). However, when someone has AF all the time (Persistent AF), catheter ablation alone is not as effective and multiple procedures may need to be performed to increase the rate of success. Multiple catheter procedures also expose patients to procedural risks, albeit low.

Surgical AF ablation: Generally a reserved option for patients who have failed medical or catheter ablation. It is also offered as a first option where the cardiologist thinks that the success rate with catheter ablation is very low. Surgical AF ablation has the highest rate of success if performed by surgeons who specialise in this type of surgery.

How to decide what is good for me?

Generally when you have AF you will be seen by a cardiac electrophysiologist who is a specialist cardiologist dealing with rhythm disorders. Your cardiologist or GP will make a referral to a cardiac electrophysiologist if they think you need further treatment for AF.

Cardiac electrophysiologists are specialists treating heart rhythms including AF. They will assess, and make recommendations for you. Surgery is generally considered a last resort but should not be delayed for too long. Long delays in correcting AF can result in lower success rates.

Surgery for treatment of AF

Surgery is generally used as a last resort for AF. AF is treated by a specialist cardiologist who is known as a cardiac electrophysiologist. They will treat AF with medication, electrical shock (DCCV) or catheter ablation. When the above strategies fail and patients have significant symptoms then they are referred for surgery. Patients with long standing AF may be referred directly for surgery due to low success rate of catheter ablation.

What is AF ablation?

Ablation involves creating scars on the wall of the atrial chambers using radiofrequency energy. It is like creating a fire break during a bushfire. Scar tissue is not able to conduct electrical impulses. During AF ablation, lines of scar tissue are created around abnormal heart tissue that generates abnormal random electrical impulses. By doing so, random impulses remain trapped within scar tissues and are not able to propagate to the rest of the heart,allowing normal sinus rhythm to persist.

Ablation can be done by a tiny catheter introduced from the groin or surgical tools. Catheters have limitations due to their small size but have the advantage of being minimally invasive. Surgical tools are very effective but their application requires heart surgery.

Surgeries for AF   –  “ALL AF ABLATIONS ARE NOT MAZE PROCEDURE “

  1. MAZE procedure – This procedure involves treatment/ablation of both atrial chambers and is the most complete ablation.
  2. Pulmonary vein isolation – this is a minimalistic target ablation of veins from the lungs that connect to the heart. Majority of AF originates around their insertion point.
  3. Left atrial ablation – This includes ablation of the pulmonary veins and back wall of the left atrium. This is very effective as the majority of AF originates from the pulmonary veins and the back wall of the left atrium.

Approach for surgical AF ablation

  1. Conventional sternotomy approach (heart needs to be stopped)
  2. Minimally invasive mini-thoracotomy approach (heart needs to be stopped)
  3. Minimally invasive thoracoscopic approach (done without stopping heart)
  4. Hybrid approach (video)(done without stopping heart)

AF ablation(MAZE procedure) using sternotomy approach:

We will use  the term “MAZE procedure” for AF ablation. The goal of AF ablation via sternotomy is to maximize ablation to include all target areas of both atrium. This is quite readily achievable via a sternotomy approach. MAZE procedure via sternotomy using currently available energy devices is one of the simplest heart surgeries compared to other heart surgeries. But it is fairly rare for patients to be referred for this approach. Patients are also reluctant to get a sternotomy for MAZE procedure.

After performing a sternotomy, the heart is supported with a heart lung machine. Some of the ablation can be performed without stopping the heart and Dr Joshi routinely performs some of the ablation without stopping the heart thereby reducing the time the heart needs to be stopped. After the initial ablation, the heart is stopped with a special solution. Initially, the left atrial chamber is opened to perform further ablation. After completion of the ablation on the left side, the left atrium is sutured closed. Next, the right atrial chamber is opened and ablation on the right atrium is completed followed by closure of the right atrial incision. Additional external ablation is performed on the vein of the heart (coronary sinus). Following this, the heart is started again. While the heart is recovering, Dr Joshi applies a device on the left atrial appendage while the heart is beating. This device is known as an Atriclip and will prevent blood going into the blind pouch ie left atrial appendage. This helps prevent stroke in patients who have ongoing atrial fibrillation. Temporary pacing wires are applied to the heart and the chest is closed. Patient is returned to the ICU. Temporary wires allow ICU specialists to control your heart rate. It is quite common for your heart to not have its own rhythm for a few days. During this time, temporary wires are connected to an external pacing box which gives impulses to your heart until it recovers its own rhythm.

Will I be in a lot of pain?

Pain is very subjective, but overall it is uncommon for patients to experience severe pain. You will be given strong painkillers, some of which may have unpleasant side effects like nausea, vomiting and constipation. Nursing staff will manage your pain medication in close collaboration with you. You are encouraged to notify staff if your pain is unbearable, prevents you from deep breathing, or keeps you awake.

Typically most patients are kept asleep with medications for 3-6 hrs to observe for stability. While you are asleep you will be breathing with breathing machine. The ICU specialist (Intensivist) is in charge of your care while you recover in ICU. When you wake up you will feel very sleepy and weak. You will notice few lines , tubes and wires connected to you which is a routine.  You will also notice a small box size of a compass  with blinking lights on top of it – this is a pacing box. Temporary wires on your heart are connected to this box. This will stay with you for 5-7 days. You will feel a bit uncomfortable with all those attached to your body. The additionals are removed as you progress in your care and most are removed by day 5. As a routine, you will be helped to get out of bed and sit in chair for few hours to help your lungs breath better. Physiotherapist will take you for a short walk on day 2 in ICU. Stay in ICU is typically for 2 days. You will be transferred to cardiac ward after for further care.

Progress in ward

You will be in a room once you arrive to ward. You will be connected to monitor so nurses can see any alarming signals from your heart rhythm. You need to be careful that the monitor leads remain attached to you body properly. If they get detached, you should inform your nurse by pressing call button. Most important thing in ward is to start getting more mobile. You will be asked to walk 5 times every day and your physio will teach you exercises. Dr Joshi will give instruction of removal of pacing wires. Removal of wires and lines are very tolerable. By day 5-7, you will be asked by physiotherapists to complete climbing of two flights of stairs. This is done to assess your fitness to be discharged at home and your independent mobility. You will have regular blood test and chest x rays. Electrolytes are frequently replaced with intravenous infusions.

Heart rhythm :

You may be in normal sinus rhythm of a slow regular heart rhythm. Dr Joshi  and cardiologist will carefully monitor your rhythm. You may slip back in AF. If that happens please don’t get disheartened. It is quite common to develop AF in first two months.

Blood thinner:

You will be discharged with warfarin or one of the alternatives. You should continue this medication until further instructions from Dr Joshi or your cardiologist. If you are on warfarin, you will need regular blood test to guide the dosage of your medication. You should only stop blood thinner in consultation with your specialist.

Going home

Most patients are expected to be discharge between 5-7 days after surgery. You will receive discharge education from your nurse who will give you information about incisions, dressing, shower etc. Pharmacist will visit you to discuss your medications which might have changed a little bit. You must remember to take discharge file with you that should include all your instructions regarding follow up appointments, medication list and other material. You should carry this file with you when you visit your cardiologist or cardiac surgeon for follow up at 4-6 weeks

Dressings

You will have a long dressing on chest. You should remove it after 4 weeks under running shower. You can remove it earlier  if it starts to come off or breaks. If you have any concerns about wound please visit your GP or notify Dr Joshi

Complications:

Generally considered a low risk operation despite complexity associated with it. In the absence of major medical problems most patients have 1%  or less risk of death or major complications. Most important complications to keep in mind is risk of bleeding and stroke. The incidence of bleeding and stroke is expected to be around 1% and if the risks are higher it will be pointed out at the time of consultation. Other major complications that are associated with any major surgery like heart surgery is infection, heart attack and kidney injury and they are fairly uncommon.

One of the important non major complication with this surgery is a risk of permanent pacemaker (PPM) which is about 5%. If your electrical system does not recover within a week than Mr Joshi will ask cardiologist to insert a PPM under local anaesthetic prior to your discharge from hospital. Insertion of PPM does not hold you long in hospital nor affects your recovery adversely.

Some patients may develop rhythm abnormality other than atrial fibrillation. This abnormal rhythm are known as Atrial tachycardia. This is complication that may require further catheter ablation by cardiologist in future if persists.

Younger patients are a risk of developing  fluid build up around the heart. This typically manifests at about 4 weeks. This is reactive fluid and younger patients are more prone. It is not harmful but can make some patients feel short of breath or feverish. If that happens you should present to ED or notify your cardiologist or Mr Joshi. The treatment involves anti inflammatory medications and in some cases taking the fluid out with needle or small incision.

If the risks of surgery are elevated then you will be informed about it at the time of consultation.

Why and when sternotomy approach for MAZE procedure?

As mentioned earlier, it is rare for patients to be referred for sternotomy MAZE procedure. Such case usually are complex AF cases where every other approach has been considered or tried or failed. Generally, sternotomy MAZE procedure are performed concomitantly when patient is undergoing other heart surgeries like valve surgery, bypass surgery , aortic surgery etc. Mostly commonly, it is performed in combination with mitral and tricuspid valve surgeries.

You should arrange an appointment to see Dr Joshi in 6-8 weeks and your cardiologist in 8 weeks. You should visit your GP withing a week after being discharged from hospital

Mr Joshi will see you for follow up after 6 weeks and then your long term follow up is organised by your cardiologist and GP. You will need holter monitor test 3-4 monthly which will be organised by your cardiologist. If you are on warfarin than your GP will guide you regarding frequency of blood test and dosage of warfarin.

One of the reason to restore normal sinus rhythm is to enable you to return to your normal life. If you had any limitations due to your heart issues then if should also get better, effectively improving quality of your life. One would be expected to return completely back to normal life but it may not be the case for all patients. If you are on warfarin or other blood thinners then necessary changes to your life style is recommended.