Atrial Flutter Ablation
In some hearts, an abnormal heart rhythm develops.
BACKGROUND
The heart is a pump responsible for maintaining blood supply to the body. It has four chambers. The two upper chambers (the right atrium and left atrium) are the chambers that receive blood as it returns from the body via the veins. The lower chambers (the right and left ventricle) are the chambers responsible for pumping the blood out to the body via the arteries. Like any pump, the heart has an electrical system that controls how it functions.
Normal heart rhythm.
In order for the heart to do its work (pumping blood throughout the body), it needs a sort of spark plug or electrical impulse to generate a heartbeat. Normally this electrical impulse begins in the upper right chamber of the heart (in the right atrium) in a place called the sino-atrial (SA) node. The SA node is the natural pacemaker of the heart. The SA node gives off electrical impulses to generate a heartbeat in the range of 60 to 100 times per minute. If you are exercising, doing strenuous work or are under stress, your heart rate will be faster. When you rest or sleep your heart rate will slow down. If you take certain medications, your heart rate may be slower.
From the Sinus Node, the electrical impulse is relayed along the heart’s conduction system. It spreads throughout both the right and left atria causing them to contract evenly.
When the impulse spreads over the right atrium it reaches the atrio-ventricular (AV) node. This is a very important structure in the heart because it is the only electrical connection between the top chambers and the bottom chambers. It is therefore the only way in which an electrical impulse can reach the pumping chambers (the ventricles). The impulse spreads through the AV node and down into the lower chambers or ventricles of the heart. This causes them to contract and pump blood to the lungs and body.
The heart is made up of four chambers. The top two chambers are call the Atria and the bottom two chambers are called the Ventricles.
The top and bottom chambers are separated by two valves the Tricuspid Valve and the Mitral Valve.
The Tricuspid Valve separates the Right Atrium from the Right Ventricle
The Mitral Valve separates the Left Atrium from the Left Ventricle
Slide 1 of 8
The top and bottom chambers are separated by two valves the Tricuspid Valve and the Mitral Valve.
The Tricuspid Valve separates the Right Atrium from the Right Ventricle
The Mitral Valve separates the Left Atrium from the Left Ventricle
Slide 1 of 8
1) The normal heart beats starts in the Sino-Atrial Node located in the Right Atrium. This acts as the spark plug to start the heart.
Slide 2 of 8
Slide 2 of 8
The normal heart beats starts in the Sino-Atrial Node located in the Right Atrium. This acts as the spark plug to start the heart.
2) Electrical conduction then activates both atria and travels to a structure called the AV-Node. The AV node acts as the ‘gate keeper’ of all electrical impulses to the ventricles.
Slide 3 of 8
2) Electrical conduction then activates both atria and travels to a structure called the AV-Node. The AV node acts as the ‘gate keeper’ of all electrical impulses to the ventricles.
Slide 3 of 8
The normal heart beats starts in the Sinus Node located in the Right Atrium. This acts as the spark plug to start the heart.
Electrical conduction then activates both atria and travels to a structure called the AV-Node. The AV node acts as the ‘gate keeper’ of all electrical impulses to the ventricles.
3) After electrical conduction passes through the AV node it travels down the Left and Right Bundle Branches which activates the Ventricles and tells them to contract.
Slide 4 of 8
Electrical conduction then activates both atria and travels to a structure called the AV-Node. The AV node acts as the ‘gate keeper’ of all electrical impulses to the ventricles.
3) After electrical conduction passes through the AV node it travels down the Left and Right Bundle Branches which activates the Ventricles and tells them to contract.
Slide 4 of 8
The heart's normal contraction can be seen on the ECG. This ECG shows normal sinus rhythm and is made up of a series of waves called the P, QRS and T wave.
Slide 5 of 8
Slide 5 of 8
Atrial activation is represented by the ‘P-Wave’ on the ECG.
Slide 6 of 8
Slide 6 of 8
Ventricular activation is represented by the ‘QRS’ complex on the ECG. This normally takes less than 120 milliseconds.
During this time the Ventricles contract and blood is pumped from the heart to the lungs and through the aorta to the rest of the body.
Slide 7 of 8
During this time the Ventricles contract and blood is pumped from the heart to the lungs and through the aorta to the rest of the body.
Slide 7 of 8
The final wave is called the T wave. During this phase the Ventricles relax. This normally takes less than 450 milliseconds.
Slide 8 of 8
Slide 8 of 8
How do abnormal heart rhythms occur?
In some hearts, an abnormal heart rhythm develops when an electrical impulse either starts from a different location, other than the SA node, or follows a route (or pathway) that is not normally present. This is what happens in atrial flutter. A short-circuit develops in the right atrium as show in the diagram below.
Atrial Flutter is due to a short circuit in one of the upper chambers of your heart termed the right atrium. This rapid short circuit has several consequences:
- The short circuit drives the pumping chambers very rapidly and sometimes erratically. This produces palpitations, shortness of breath, and tiredness. In some people it can also cause dizzyness and chest pain.
- The short circuit results in ineffective pumping of the upper chambers. This leads to slow blood flow in both of these upper chambers (the left and right atrium). This can rarely cause blood clots and possibly stroke. One of the major reasons to cure atrial flutter is to prevent this risk of stroke.
Typical flutter is an abnormal rhythm of the right atrium.
It is a simple circuit that rotates around the right atrium at over 300 beats per minute.
The typical atrial flutter circuit is shown by the orange arrows.
Slide 1 of 5
It is a simple circuit that rotates around the right atrium at over 300 beats per minute.
The typical atrial flutter circuit is shown by the orange arrows.
Slide 1 of 5
Atrial flutter has a classical ‘saw-toothed’ pattern on the 12 lead ECG. During atrial flutter, the atria beat 2-4 times faster than the Ventricles. Because the atria and ventricles are beating out of synchrony patients will notice symptoms of palpitations or shortness of breath.
Slide 2 of 5
Slide 2 of 5
Although right atrial flutter is the most common form of atrial flutter there are many other possible flutter circuits that can be formed in both atria. Abnormal flutter circuits can also form after open heart surgery.
Slide 3 of 5
Slide 3 of 5
Patients with surgically corrected congenital heart disease or previous cardiac surgery are prone to atrial flutter. Because of their underlying anatomy, arrhythmias in these patients can be quite challenging.
We have a vast amount of experience in treating atrial flutter in these complex post-surgical patients.
Slide 4 of 5
We have a vast amount of experience in treating atrial flutter in these complex post-surgical patients.
Slide 4 of 5
The majority of the flutter circuits in these patients are due to re-entry circuits.
Re-entry circuits revolve around areas of scar or around surgical sutures lines from their original surgery.
Slide 5 of 5
Re-entry circuits revolve around areas of scar or around surgical sutures lines from their original surgery.
Slide 5 of 5
What treatments are available for atrial flutter?
- Atrial flutter can be treated with medication. In some people these medicines can be very effective. In others however, the medications are ineffective and may produce side effects. If you elect to take medication, your doctor will discuss the different options and the possible side effects of these medications.
- DC Shock. When the heart is in flutter it can be reverted to the normal rhythm with a “shock on the chest”. You receive a short general anaesthetic and the shock reverts the rhythm to normal in almost all cases. With this approach the possibility of the flutter returning remains present (approximately 50% of patients will have another episode of atrial flutter over the next year). In addition, most patients will also require a medicine to try to prevent the flutter coming back.
- Blood Thinning medication. Because of the risk that atrial flutter may return with the above treatments, most patients with atrial flutter will require blood thinning medication to prevent blood clots forming. At your doctors discretion this may either be with aspirin or warfarin.
- Radiofrequency ablation. This procedure carries a success rate of approximately 95% for curing the atrial flutter. The risk of the flutter returning at some time in the future is approximately 10%.
