“Dr Irena’s” Health Tips – No. 6

We recently had contact with a retired UK doctor who now lives in North Cyprus and met her at Kamiloglu Hospital – Kyrenia Medical Centre where she was looking after reception/patient liaison along with other English speaking people who are giving their time to ensure a good medical service for English speaking expatriates.

Irena kindly offered to write some articles about basic health issues which may be of interest to our readers.

By Irena Hulson

Atrial Fibrillation

Atrial fibrillation facts

• Atrial fibrillation is an abnormal rhythm of the heart.

• Atrial fibrillation is caused by abnormal electrical discharges within the atria.

• Atrial fibrillation reduces the ability of the atria to pump blood into the ventricles and usually causes the heart to beat too rapidly.
  • Symptoms of atrial fibrillation include palpitations, dizziness, fainting, weakness, fatigue, shortness of breath, and chest pain although some people have no symptoms.
  • Complications of atrial fibrillation include heart failure and stroke.

• Atrial fibrillation can be diagnosed by physical examination, electrocardiogram, Holter monitor, or patient-activated event recorder.
• Treatment of atrial fibrillation is directed towards controlling underlying causes, slowing the heart rate and/or converting the heart to normal rhythm, and stroke prevention using blood-thinning medications.

• Medications are commonly used in the longer term to control or prevent recurrence of atrial fibrillation, but medications may not be effective and may have intolerable side effects.

• Electrical cardio version is successful in over 95% of patients with atrial fibrillation, but 75% of patients have a recurrence of atrial fibrillation within 1 to 2 years.

• Some doctors may leave patients in atrial fibrillation for the longer term provided the heart rate is under control, blood flow is adequate, and blood is adequately thinned with medications.

• Non-medication treatments of atrial fibrillation include pacemakers, AV node ablation, atrial defibrillators, and the Maze procedure.

• Pulmonary vein isolation shows promise for the treatment of atrial fibrillation and has a high rate of success; however, longer-term experience is necessary.

Preventing atrial fibrillation and treatment

After successful cardio version many patients (up to 75%) may experience recurrence of atrial fibrillation within 12 months. Therefore, many patients will need long-term treatment with medication to prevent a recurrence of atrial fibrillation; however, medication(s) are effective only 50% to 75% of the time in preventing recurrence. Moreover, many patients cannot tolerate the side effects of long-term medication. For these reasons, several procedures have been developed to treat and prevent recurrence of atrial fibrillation; they include:

• Ablation of the AV node with implantation of a pacemaker

• Implantation of a pacemaker

• Implantation of an atrial defibrillator

• Maze procedure

• Isolation of the pulmonary vein

Ablation of the AV node with implantation of a pacemaker.

Ablation of the AV node is a procedure that destroys the AV node so that the atrial electrical discharges cannot pass through the AV node to activate the ventricles. The procedure usually is performed in a cardiac catheterization unit or an electrophysiology unit of a hospital.

1. Procedure. For ablation of the AV node, patients are given a local anesthetic to minimize pain and are mildly sedated with intravenous medications. Using X-ray guidance, a wire (catheter) is inserted through a vein in the groin to reach the heart. Electrical recordings from inside the heart help to locate the AV node. The AV node is destroyed (ablated) using heat delivered by the catheter. After successful ablation of the AV node, electrical discharges from the atria can no longer reach the ventricles. Destruction of the AV node (whether by catheter ablation or by disease that occurs with age) can lead to an excessively slow rate of ventricular contractions (slow heart rate). Therefore, a pacemaker is implanted in order to provide the heart with a minimum safe heart rate.
2. Benefits of ablation of the AV node.  The benefits of   ablation of   the AV node and implantation of a pacemaker include:

• Resumption of a regular heart rate (even though a pacemaker may be determining the heart rate);

• Relief from palpitations, fainting, dizziness, and shortness of breath; and

• Ability to stop medications and avoid their potentially serious side effects.

3.  Risks of ablation of the AV node.

Potential complications of ablation of the AV node and     permanent implantation of a pacemaker include bleeding, infection, heart attack, stroke, and introduction of air into the space between the lung and chest wall, and death. Still, this technique has helped many patients with severe symptoms to live normally.

4. Candidates for ablation of the AV node.

Candidates for ablation of the AV node are patients with atrial fibrillation who respond poorly to both chemical and electrical cardio version. These patients experience repeated relapses of atrial fibrillation, often with rapid rates of ventricular contractions despite medications. Ablation also may be an option for patients who develop serious side effects from the medications that are used for treating and preventing atrial fibrillation.

 5. Limitations of ablation of the AV node.

Ablation of the AV node only controls the rate with which the ventricles beat. It does not convert atrial fibrillation to normal rhythm. Therefore, blood clots still can form in the atria and patients are still at risk for strokes. Thus, there is a need for long-term anticoagulation in addition to the permanent pacemaker.

Pacemakers.

Permanent pacemakers are battery-operated devices that generate electrical discharges that cause the heart to beat more rapidly when the heart is beating too slowly. Recent studies suggest that some patients with recurrent paroxysmal atrial fibrillation can benefit from the implantation of a permanent pacemaker. Although the reasons for this benefit are unknown, regular electrical pulses from the pacemakers may prevent the recurrence of atrial fibrillation. Furthermore, newer pacemakers that can stimulate two different sites within the atria (dual site atrial pacing) may be even more effective than standard pacemakers in preventing atrial fibrillation. Nevertheless, permanent pacemaker implantation cannot be considered as standard non-medication treatment for atrial fibrillation.

Implantable atrial defibrillators.

Implantable atrial defibrillators can detect and convert atrial fibrillation back to a normal rhythm by using high-energy shocks. By detecting atrial fibrillation and terminating it quickly, doctors hope that these devices will prevent recurrences of atrial fibrillation over the long term.

Atrial defibrillators are surgically implanted within the chest under local anesthesia. These devices deliver high-energy shocks to the heart that are somewhat painful. Atrial defibrillators are not useful in patients with chronic sustained atrial fibrillation and are suitable only for patients with infrequent episodic attacks of atrial fibrillation.

Maze procedure.

Many doctors believe that the atria cannot fibrillate if they are sectioned into small pieces so that the conduction of the electrical current through the atria is interrupted. During the Maze procedure, numerous incisions are made in the atria to control the irregular heartbeat and restore a regular rhythm to the heart.

1. Procedure. The Maze procedure is most commonly performed via open-heart surgery. Some electro physiologists (doctors specially trained to treat abnormalities of rhythm) are now attempting to perform the Maze procedure using catheters inside the heart that are passed through a vein in the groin without open heart surgery. Unfortunately, the success rate using the catheter is below 50% and complications (such as strokes) may occur.
2. Effectiveness of the Maze procedure. The Maze procedure done surgically (using open heart surgery) has been reported to correct atrial fibrillation in 90% to 99% of patients. Only 15% to 20% of the patients need a pacemaker after surgery, and there is only a 30% chance of requiring long-term medications to maintain a normal rhythm.
3. Risks of the Maze procedure. The surgical Maze procedure involves open-heart surgery and the pumping of blood by an external bypass pump while the surgery is performed, much like patients undergoing cardiac bypass surgery. The complications are not insignificant and include stroke, bleeding, infection, and death. Therefore, doctors usually do not recommend a surgical Maze procedure for the treatment of atrial fibrillation unless the patient is undergoing open-heart surgery for another condition (such as for coronary artery bypass or replacement or repair of a diseased heart valve).

Editor’s Note

“The opinions, advice or proposals within the article are purely those of the author and do not, in any way, represent those of Cyprusscene.com“