Surgical Management of Atrial Fibrillation
Heart arrhythmias (abnormal heart rhythms) originate in the atria (the receiving chambers of the heart). A common arrhythmia is called Atrial Fibrillation whereby the heart beats too rapidly as well as irregularly. This not only can cause patient discomfort and anxiety, it can also result in potentially catastrophic complications such as stroke, heart failure, exercise intolerance or even death.
Pooling of the blood in the left atrium due to the abnormal rhythm can cause the development of blood clots (thromboembolism) that are spread throughout the arterial system of the body resulting in possible strokes. This can be ameliorated by the use of blood-thinning medication but this adds an ongoing risk of spontaneous bleeding with a 1 – 2% risk of a major bleeding event occurring per year in well-controlled patients.
Despite advances in drug treatment, a significant number of patients remain affected by atrial arrhythmia.
Direct surgical approaches to atrial fibrillation were pioneered by Dr James Cox in the United States with the Maze Operation.
Since 1994 at Westmead Hospital we have had an interest in direct surgical treatment of atrial fibrillation using a slightly different strategy to the Maze Operation where instead of using surgical incisions which are then sutured up to provide a block to atrial conduction a radiofrequency device is used. This produces an electrical burn on the atrial wall, which is relatively narrow. The first devices were made in-house at our hospital and used in operating on our early patients in our series. We later have used several commercially available devices over the last few years.
The surgical technique we have employed works on the principle that most atrial fibrillation is caused by random waves of activation going around and around the atrial chambers and that organisation of these waves using a pattern of lesions across which the electrical impulses cannot pass can organise the waves into a normal rhythm with activation of seven strips of atrium which each contract as the wave passes down them towards the mitral and tricuspid valve rings, which effectively insulate the impulses from the ventricles excepting one place where the Bundle of His crosses into the ventricles and transmits the atrial rhythm to the ventricles as in the normal heart. This technique we have employed retains the atrial contraction function better than Maze type approaches but still cures atrial fibrillation in the vast majority of patients depending on their individual situation.
I think that any patient with atrial fibrillation associated with other heart disease requiring surgery should be considered for an operation to attempt to cure their atrial fibrillation if they are in permanent atrial fibrillation or to minimise the risk of recurrence if they are in paroxysmal (intermittent) atrial fibrillation. Using the techniques we have developed there is a very low incidence of creation of other abnormal atrial rhythms such as atrial flutter which has been noted to occur after other surgical approaches.
There is also a small group of patients whose atrial fibrillation is causing them such severe symptoms or lifestyle problems, for example, inability to tolerate blood-thinning medication, that direct surgical treatment with a high probability of success is a reasonable option. This may be particularly relevant in the younger patient.