The heart beats because of a set of electrical impulses. The myocardium or heart muscle contracts when the electrical signal arises from the sinoatrial node in the upper right chamber and passes to the atriventricular node. The electric impulse proceeds through the heart’s muscles to the lower chambers called the ventricles causing them to contract. The rhythmic contractions of the heart muscles are necessary to maintain the flow of blood. An irregular heart beat is known as an arrhythmia.
A number of different types of arrhythmia exist and are named on the basis of the atria or ventricle in which they occur. There are three primary reasons for arrhythmia or an abnormal heart beat.
- The heartbeat starts with an electrical impulse which does not originate in the sinoatrial node.
- The sinoatrial node may not be able to set a normal heartbeat rhythm due to some problem.
- There is a block or delay of the electric impulse which causes the heartbeat to become irregular.
Arrhythmias are diagnosed with a combination of a physical examination, EKG, and study of the individual’s medical history.
What is Atrial Fibrillation?
Atrial fibrillation is the most common arrhythmia to affect the heart. The irregular and fast heart beats associated with atrial fibrillation arise in the atria or top chamber of the heart. Instead of a single electrical impulse starting from the sinoatrial node and proceeding through the atriventricular node to the ventricles, a number of impulses begin simultaneously through the atria. This results in a rapid and arrhythmic heartbeat. The condition is potentially dangerous as it could lead to cardiac failure.
Atrial fibrillation can double the risk of death for an individual suffering from the arrhythmia. It increases the possibility of a stroke by five times and can cause congestive heart failure. There is a continuous palpitation in the chest and the individual may feel breathless and tired when afflicted with this condition. It can last from a few hours up to many days.
Treating Atrial Fibrillation with the Maze Procedure
Atrial fibrillation causes an irregular heart rhythm. The maze procedure is a surgical intervention that tries to solve the arrhythmia by interrupting the multiple electric impulses causing the condition. Essentially the procedure makes it difficult for the electric impulses to complete their journey through the heart muscle.
In order to do this, the surgeon will make incisions in both the left and right atria to form scar tissue. Once the incisions are made, they will sew up the atrium to allow normal blood flow. As the incisions heal, the scar tissue in the atria ensures that the abnormal electric impulses can’t pass through the myocardium causing the atrial fibrillation. The procedure takes about four hours.
The electric impulse can now only travel from the sinoatrial node to the atriventricular node ensuring a regular heartbeat. The surgery is performed on the beating heart without the heart lung machine. The procedure leaves only one possible route for the electric impulses similar to the concept of a children’s maze where there is only one path that leads out of the puzzle. This is the reason why it is called the maze procedure.
Recovery and Rehabilitation Post Maze Procedure
Most maze surgeries are done in conjunction with other surgeries such as coronary artery bypass grafting, mitral valve repair, or valve replacement. The maze procedure has a success rate of 60 to 95%. It can be performed in a minimally invasive manner, as well as in an open chest surgery. The recovery of the individual will depend on various interlinked factors.
The fastest recovery is reported in individuals who have only been treated for atrial fibrillation without any other cardiac condition. The lowest success rates for the maze procedure are seen in individuals who may have associated heart problems such as an enlarged heart or a valve problem. Post surgery, which is conducted under general anaesthesia, the individual will be kept under observation in the intensive care unit overnight.
Then the individual will be moved to a regular hospital room and stays there for four to eight days. The individual is given a short course of anti-arrhythmic drugs and is encouraged to resume normal activities two to four weeks after the surgery. As there is a danger of fluid build up after the surgical procedure, the individual may also be prescribed diuretics. Aspirin may be prescribed to counter the possibility of blood clots. Medication prescribed will differ for different individuals.
The rehabilitation program includes encouraging the individual to be physically active as long as the activities do not exert the breastbone and upper arm area. Walks are the best form of exercise and individuals are encouraged to pursue it. Most individuals feel normal after the surgical maze procedure within six weeks.
Reviewed by Susha Cheriyedath, MSc