Normally, the heartbeat is triggered by electrical impulses which start in a special area of the heart tissue called the Sinoatrial (SA) node. From the SA node, these impulses flow down and across special electrical conduction pathways (cells) which cover the whole heart. These electrical impulses result in your heart squeezing (beating) regularly like a clock; diseases within the electrical pathways of the heart cause an abnormal irregular heart rhythm to occur and these are called arrhythmias. Atrial fibrillation is the most common heart arrhythmia and is sometimes referred to as A.F. It is a condition in which lots of small abnormal electrical pathways (electrical circuits) develop within the two upper chambers of the heart or ‘atriums’ causing the heart to beat erratically and often fast.
Atrial fibrillation (AF) is the commonest cardiac arrhythmia in humans and affects 0.4% of the general population and 5% of individuals older than 65 years, with the prevalence expected to double in the next 50 years. In many patients it is the cause of debilitating symptoms such as lethargy, breathlessness, dizziness and palpitations. AF dramatically increases the risk of hospitalization, heart failure, stroke and death.
When atrial fibrillation is often controlled by medications and most people live a normal life with few symptoms. There are a number of modifiable risk factors that patients and their doctors should try to change first before therapies are considered or if the patient is symptomatic along with the prescribed therapies.
However, if poorly controlled or resistant to medications, this condition can become serious symptoms, particularly if the heart beats too fast causing a drop in blood pressure or if blood clots within the heart escape and cause a stroke. All forms of ablation are to improve quality of life by abolishing disabling symptoms and are not for prognostic purposes. Invasive treatment options for AF include.
- Electrical cardioversion, where the cardiologist or surgeon uses special paddles on top of the chest/heart to “shock” or “short circuit” the heart back into a normal rhythm.
- Catheter ablation, where the cardiologist uses a special tool to destroy (ablate) the abnormal electrical tissue cells that cause the arrhythmia. This is done in a cardiac catheterization laboratory (cath lab).
With the current approach of percutaneous catheter ablation, some patients with longstanding persistent atrial fibrillation may undergo two, three or more procedures in order to restore sinus rhythm in the long term. If these treatments do not work or if a patient is due to undertake cardiac surgery for a different reason (coronary artery by-pass, valve repair/replacement) a surgical procedure can be carried out. This type of surgery is called Concomitant Maze Surgery. Specific patients could have Stand Alone Surgical Cardioablation or Hybrid Cardioablation, where two procedures a surgical one and a percutaneous one are combined to achieve better results, for a specific group of patients.
Surgery for atrial fibrillation – Concomitant Maze Surgery
During a Maze procedure, a surgeon creates a “maze” of new electrical pathways in order to let electrical impulses travel more easily through the heart.
If you get occasional atrial fibrillation or if your atrial fibrillation has been persistent for up to 12 month or so, we recommend an isolated Maze procedure to the left atrium. If however your arrhythmia has been present for a much longer period then you are best treated with a more extensive procedure that includes pulmonary vein isolation plus other linear lesions in order to destroy the abnormal circuits.
Your surgeon will use special equipment (called a Cardio-ablator) to create a series of shallow lesions on your heart. These lesions work like the “Great Wall of China”. They separate the abnormal electrical pathways from the non-diseased heart cells allowing a normal heart rhythm to develop. The number of lesions required will depend on the “type “of atrial fibrillation your are suffering from. The type of cardioablator will depend on your surgeons’ preferences.
It is not always necessary to open the heart to perform this kind of operation but it may be necessary, if extensive lesions are needed or valve surgery is to be performed.
Surgical ablation can be performed as stand-alone operation, but it is usually undertaken in conjunction with other surgical procedures at the same time.
Convergent Procedure – Hybrid Treatment for atrial fibrillation
The Convergent Approach is a hybrid approach combines these two therapies using the standardized percutaneous techniques along with a new, minimally invasive surgical procedure. The Convergent Approach is typically offered to patients with AF of longer duration, patients with enlarged left atria (upper chamber of the heart), or those who have undergone unsuccessful attempts at percutaneous ablation.
The initial surgical part of the procedure
Prior to the procedure, you will be given a general anesthetic to minimize any discomfort. During the procedure, you will be lying on your back while you are continuously monitored throughout the procedure by medical personnel. As with any surgery, success will depend on your age, activity level and other factors. Your doctor will determine if you are a good candidate for the Convergent Approach procedure.
Your surgeon will create an 2cm incision just below the breat bone (or in the upper part of the abdomen) and then willget access to the pericardium (the sac that holds the heart). A cannula will be inserted into the chest cavity to provide a pathway for the ablation device (EPi-Sense Device) to reach the back of the heart and perform the ablation using Radiofrequency energy. The ablation device will be suctioned on to the heart and then the physician will turn on the radiofrequency energy to create a “scar” on the heart and burn as many areas that generate additional electricity causing AF.
Following your procedure, you will be monitored during your recovery. Your doctor will determine how long you need to be in the hospital. If necessary, your doctor will discuss prescriptions for cardiac medications and pain management. Before you go home, your doctor will schedule a follow-up appointment at 6 weeks from the operation date and you will be offered a date for the second step of this procedure.
Second step – percutaneous completion of ablation
Following the surgical ablation performed with the Epi-Sense Device, a new electrophysiological study will be performed approximately 6-8 weeks from the initial operation and by a designated consultant electrophysiologist at the electrophysiology laboratory.
The electrophysiologist will put catheters (fine electrical wires) into a blood vessel in the groin and thread it up to the heart giving access to the inside of the heart. Detailed mapping of the electrical activity will take place and if necessary, additional, supplementary lesions will be made in order to complete the treatment.
Following your procedure, you will be monitored during your recovery. Your doctor will determine how long you need to be in the hospital. If necessary, your doctor will discuss prescriptions for cardiac medications and pain management. You will be seen in the outpatient clinic 3 months after the second procedure.
Excision of left atrial appendage
The left atrial appendage (LAA) is an area within the left atrial chamber where blood can pool and become immobile during atrial fibrillation. Static blood can lead to clot formation. Dislodgement of this clot can cause devastating embolic episodes known as strokes
The left atrial appendage is recognised as a key site of thromboembolic origin in atrial fibrillation (AF), acting as the primary source of around 90% of embolic strokes in non-valvular AF patients.
The most serious complication of AF is a cerebral stroke. Generally, this disease occurs with a frequency of 8% in the Western population; in patients over 65 years old, it is as high as 20%. Approximately 20% of strokes are caused by AF. If a stroke occurs during atrial arrhythmia, the subsequent cerebral ischaemia is much more serious than ischaemia caused by non-cardioembolic events. Stroke is currently the third leading cause of death in Western countries.
removal of the left atrial appendage along with cardioablation for atrial fibrillation can lead to a significant reduction of the risk of stroke and the need for blood thinning medications called anticoagulation. A number of techniques have been used over the years to treat/exclude/excise the left atrial appendage. The technique most often used to surgically excise of the left atrial appendage is with endo-GIA automatic stapling and cutting device.
Currently the safest and most commonly used device is the AtriClip can offer 97% successful and atraumatic exclusion of the left atrial appendage with no device migration or device related complication recorder currently. The AtrtiClip comes at different size and the appropriate size is used to fit to the specific anatomy of the patient. The AtriClip can be applied during other cardiac operations or as a minimally invasive, stand alone, day case for patient who can not have anticoagulations due to contraindications or side-effects.
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