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Cardiac Surgery > Atrial Fibrillation Atrial Fibrillation Atrial fibrillation is the most common arrhythmia or abnormal heart beat. Two to three million Americans suffer from this disease. There are an estimated 100,000 to 200,000 people in the Phoenix, Arizona area with atrial fibrillation. Ten percent of the population age 70 or greater suffer from atrial fibrillation. Current treatments need improvement to limit complications and early death.The normal heart rhythm begins in a specific region of the atrium and then spreads through the conduction pathways through the ventricles to provide a normal sinus rhythm. Atrial fibrillation is characterized by a rapid and irregular activation of the atria. This disturbed electrical activity causes abnormal emptying of the atria. Blood does not flow normally and is prone to clot. These clots can then embolize and travel throughout the circulation, causing strokes, pulmonary emboli, and many other problems. The abnormal atrial contractions with atrial fibrillation decrease cardiac output through a variety of mechanisms. The basic loss of coordination affects cardiac output and the abnormal spread of electrical impulses affects normal atrial and ventricular emptying. The response to exercise and even many basic activities such as walking normally result in an orderly change in heart rate. This change in heart rate is controlled by the conduction system of the heart. When proper electrical control is lost, atrial arrhythmias often result leading to palpitations and a variety of premature atrial contractions. Subsequently, atrial fibrillation often results. Atrial fibrillation is associated with many other disorders. Firstl, more than 70% of patients with atrial fibrillation have underlying structural heart disease; either coronary artery disease or valvular disease. Atrial fibrillation is also associated with hypertension, thyroid disorders, pericarditis, and lung disease. Congenital heart defects are associated with atrial fibrillation and some of these defects are only detected when the arrhythmia develops. Serious disease of the conduction system of the heart sometimes results in the development of sick sinus syndrome and atrial fibrillation. Most patients with this condition will require a permanent pacemaker if their atrial fibrillation cannot be cured. Atrial fibrillation can develop at any age, but in general it begins to appear in the fifth decade of life and continues to increase in prevalence so a patient in their 70s has about a 10% chance of having atrial fibrillation. At first, atrial fibrillation usually presents as uncomfortable intermittent palpitations, which may lead to a feeling of lightheadedness and a general sense of anxiety and uncertainty. It is difficult for those who have not experienced atrial fibrillation to understand the impact that it can have on one's daily life. Battling the physical and emotional effects of this arrhythmia is debilitating, yet no one knows that the battle exists because there are few outward physical symptoms. Employers, family members and yes, even treating physicians may be unaware of the decrease in functional capacity that atrial fibrillation causes. As a result, patients often feel that others think that they are "exaggerating" their symptoms. Because atrial fibrillation is so unpredictable, patients are often reluctant to travel and may even avoid committing to social engagements. Frequent trips to the hospital for repeated episodes of atrial fibrillation can completely disrupt one's life, causing significant emotional and physical distress to victims and families alike. Types of Atrial Fibrillation Isolated atrial fibrillation, which is not associated with an identifiable cause or cardiac abnormality, is called Lone atrial fibrillation. Paroxysmal atrial fibrillation occurs intermittently and varies in frequency and duration from seconds to hours or days. This form of atrial fibrillation is interspersed with long intervals of normal sinus Rhythm. Both Lone and Paroxysmal atrial fibrillation tend to occur in younger, more active patients. These rhythms are easily recognized by patients and are often incapacitating, leading to frequent office visits, anxiety and frequent hospitalization. Persistent or chronic atrial fibrillation is a more dense form of the arrhythmia where atrial fibrillation is present as the sole rhythm. This form is often less responsive to traditional treatment by rhythm controlling medications and cardioversion. Treatment Strategies Medications to maintain Sinus Rhythm The underlying goal of therapy for atrial fibrillation is the restoration of normal sinus rhythm. Medications can help to decrease atrial excitability and automaticity. These include drugs such as Quinidine, Procainamide, Disopyramide and newer drugs such as Amiodarone and Sotalol. The effectiveness and tolerance of these medications is patient specific. Some can tolerate specific medications well, and find durable benefit. Other patients may not. Current antiarrhythmic drugs are not specific to the atria, and the ventricular side effects may be considerable. Long term side effects of some medications such as Amiodarone are troubling. Medications to Control Ventricular Rate Symptoms associated with atrial fibrillation can be lessened by controlling the ventricular heart rate. The irregular flopping sensation in the chest that is so frightening and uncomfortable to patients is from the abnormal ventricular heart rate. Patients cannot sense atrial heart rate, but the ventricular rate is evident from simply feeling the arterial pulse. The faster the ventricular rate, the more symptomatic patients become. The goal of medications such as beta blockers, calcium channel blockers and Digoxin is to decrease the excitability of cardiac cells and to slow the conduction of electrical impulses through the atrioventricular node. Control of the ventricular rate is also important to avoid the development of permanent physiologic changes to cardiac cells. This cardiomyopathy may result in a final permanent remodeling of heart muscle that can lead to progressive heart failure and death. Unfortunately, heart rate is not easy to control. Physiology is variable and it may be possible to control resting rate, but not rates in response to stress and exercise. Medications to avoid Stroke The irregular atrial contractions of atrial fibrillation cause abnormal emptying of the atria. This leads to blood clots, which can then embolize throughout the body, leading to stroke, limb loss and other life-threatening problems. To reduce this risk, anticoagulants are prescribed to thin the blood and make clots less likely to form. Coumadin is the usual drug used. Frequent blood tests such as the INR are used to monitor effectiveness of Coumadin. An INR of 2.0 to 3.0 is effective in reducing the risk of blood clots in atrial fibrillation. Unfortunately, many patients have difficulty taking Coumadin and following up with the necessary tests and are thereby ineffectively treated. Cardioversion Shocking the heart in a controlled setting with appropriate sedation, anticoagulation and cardiac monitoring can reprogram the heart back into a normal sinus rhythm. This form of therapy is used in cases of paroxysmal atrial fibrillation, after ablation procedures and after other forms of cardiac surgery. In cases of persistent atrial fibrillation it is unlikely to be durable. Endovascular Catheter Ablation Procedures These procedures are performed in a cardiac catheterization laboratory. Catheters are used to study the origins of the abnormal rhythms and to ablate foci or starting points of the abnormal rhythm. These procedures are lengthy and require special expertise in electrophysiology. In some cases, the atrioventricular node is ablated or destroyed in order to blunt the ventricular response to atrial fibrillation and a permanent pacemaker is implanted. In this case, atrial fibrillation continues to be present, but the ventricular rate is controlled. MAZE Procedure: Surgery to Cure Atrial Fibrillation Jim Cox pioneered surgery to channel the abnormal impulses of atrial fibrillation through a MAZE whereby these impulses could be directed to provide normal atrial transport and a normal sinus rhythm. Evolution of this surgery has led to the development of safer energy sources and even allows minimally invasive surgery in selected patients. The MAZE procedure offers hope for a CURE for atrial fibrillation. It can be combined with traditional cardiac surgery to improve the blood supply to the heart or to correct valve disease or congenital conditions. The Maze procedure can be performed as sole therapy for chronic atrial fibrillation via open heart surgery. For selected patients, a thoracoscopic procedure can be performed allowing rapid recovery and a high rate of success. Surgeons in our group can arrange consultation for these approaches to surgical treatment of atrial fibrillation. The workup involves a complete history and physical Exam, an EKG, some laboratory tests, a chest X ray, an echocardiogram and possibly a cardiac catheterization. While not all patients are candidates for surgery to cure atrial fibrillation, these operations can be safely performed in many patients with acceptable risk and excellent long term outcome. We are committed to developing and using the newest appropriate surgical approaches to treat atrial fibrillation and to follow our patients and assist in postoperative medical management to keep patients in normal sinus rhythm. Click here to read about MAZE in the news: Revolutionizing Treatment for AF: The MicroMaze Procedure The surgeons at Desert Cardiothoracic Surgeons would be happy to answer any questions that you may have regarding the surgical treatment of atrial fibrillation. Feel free to contact us anytime at (480) 844-2020. Click here for more information on the MAZE procedure. For more information on Atrial Fibrillation, click on the links below: |
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The content on this website is intended to provide you with a better understanding of coronary artery disease, beating heart bypass surgery and endoscopic vessel harvesting. The procedures described in this website and related links may not be appropriate for all patients. The information on this website and maintain an open dialogue with you and your an informed discussion with a physician, and is not an endorsement or recommendation of any particular physician. |
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