What is Atrial Fibrillation?
Atrial fibrillation (AFib) is an irregular heart rhythm (arrhythmia) caused by abnormal and chaotic electrical activity in the top chambers of the heart. AFib may cause rapid irregular heart rates (palpitations), and, if untreated for prolonged periods, can lead to weakening of the heart muscle. During AFib the heart is less effective at pumping blood. This may cause dizziness, weakness, fatigue and reduced energy. Occasionally people with AFib have no symptoms. In this instance AFib would likely be discovered during a routine medical examination. The severity of symptoms associated with AFib can vary greatly from person to person.
What are the types of AFib?
AFib can be paroxysmal (coming and going for minutes or hours at a time) or persistent (present for days and requiring a procedure known as a cardioversion). Episodes of AFib are rarely life-threatening but can be debilitating due to the severity of the symptoms.
What are the causes of AFib?
AFib is more common in individuals with pre-existing heart disease, especially in those who have had a previous heart attack or have valve disease. Other conditions associated with AFib include emphysema, obstructive sleep apnea, high blood pressure, overactive thyroid disease and aging. These conditions make the atria (the upper two chambers of the heart) more vulnerable to AFib.
What causes an AFib episode? For many the episode is triggered by rapid electrical signals coming from the four pulmonary veins (PVs). These vessels carry blood from the lungs back to the heart and attach to the back of the left atrium. Each PV is surrounded by a heart muscle sleeve, which is normally electrically silent. In patients with AFib, this muscle can produce bursts of electrical activity that often start and continue the AFib in the rest of the atria.
What treatments are available for AFib?
The two major reasons to treat AFib are to address the undesirable symptoms associated with having AFib and to reduce the associated risk of having a stroke.
- Medications—Anti-arrhythmic medications influence the electrical activity of the heart and suppress abnormal rhythms. Taken individually each of these drugs has no more than a 50 percent chance of eliminating all episodes of AFib. However, medications can reduce the frequency, duration and intensity of episodes. It’s also important to note that all medications have side effects. While most of the side effects caused by anti-arrhythmic medications are mild, the possibility of more severe and life-threatening side effects should be discussed with the prescribing cardiologist. Beta blockers, calcium channel blockers and digoxin are the types of medications used to slow and control the heart rate during AFib. Occasionally a pacemaker may be needed along with medications to control AFib.
- Electrical Cardioversion—If AFib persists and does not terminate on its own, a procedure called an electrical cardioversion may be performed. During a cardioversion the patient is anesthetized and then a low-energy electrical shock is administered to the patient’s heart. The shock restores the heart’s normal rate and rhythm. Cardioversion works immediately for most people. However, AFib can recur in the days, weeks and months after the procedure is performed.
The best way to treat AFib depends on a number of factors, including the presence of other heart problems, the frequency and severity of symptoms, whether the AFib is paroxysmal or permanent and how well other treatments have worked.
AFib can cause blood clots to form in the fibrillating atria. Those clots can cause a stroke if they become dislodged and travel to the brain. The risk of developing a blood clot is greatest in an older patient with underlying heart disease and high blood pressure. Those who have had a prior stroke are also at higher risk. (Younger patients without any other heart disease have minimal risk.) Taking blood thinners may significantly lower the risk of a stroke for those most at risk. If you have AFib, you should discuss the need for blood thinners with your physician.
Pulmonary Vein Isolation Procedure
If AFib symptoms cannot be controlled with medication alone, the patient may be a candidate for a procedure called pulmonary vein isolation (PVI). This procedure is performed by a cardiac electrophysiologist. During PVI a thin wire (catheter) is fed into the heart near the pulmonary veins. Energy applied to the tip of the catheter is used to inactivate (ablate) the atrial muscle around each of the pulmonary veins. The result is that the electrical signals from the pulmonary veins can no longer trigger AFib.
What should I expect during the procedure?
- Prior to the procedure, a special ultrasound (transesophageal echo) is usually performed to ensure that there aren’t any blood clots in the heart. A CT scan is sometimes performed for the same purpose.
- The procedure can take approximately three to five hours.
- A team of nurses, technical staff, the cardiac electrophysiologist and an anesthesiologist will be present.
- Patients are usually under general anesthesia for this procedure.
- Special intravenous sheaths will be placed in the veins in the appropriate areas, and catheters will then be threaded through the sheaths and positioned in the heart.
- An ultrasound probe mounted on a catheter is also positioned in the heart. The probe allows the electrophysiologist to see the veins and catheters while performing the ablations. A needle is passed across the thin membrane that separates the right and left atrium to allow catheters to be placed in the left atrium. The catheters record the heart’s electrical activity to enable the creation of an electro-anatomical map of the heart. The tip of the catheter is then positioned around each pulmonary vein, and energy is applied to the atrial tissue.
- Occasionally other abnormal heart rhythms that can trigger AFib may be identified. This includes atrial flutter and atrial tachycardia. These abnormal rhythms can be ablated during the same procedure.
- The catheters and sheaths are removed after the procedure is finished. The patient is then admitted to the hospital’s telemetry unit for overnight monitoring. The patient should stay in bed in a stationary position without bending the legs for several hours after the procedure. Most patients go home the following morning.
What can I expect after the procedure?
Prior medications will normally be continued after the procedure. Instructions will be given to the patient about the proper dosing of their anticoagulation (oral blood thinner) regimen. These instructions will vary depending on the type of anticoagulation medication the patient is taking.
For at least a week after the procedure, it’s important to avoid vigorous physical activity or lifting more than 10 pounds. Normal activities (such as walking at a normal pace) can resume the day after the procedure.
Patients should be able to return to work within three to four days.
It is not uncommon to experience some chest discomfort after the procedure, particularly when taking a deep breath or changing position. This discomfort usually goes away within a few weeks. Sometimes an anti-inflammatory medication like colchicine will be prescribed to help control this type of chest pain.
The tissues involved in the ablation are easily irritated, and recurrences of AFib during the two to three months following an ablation procedure can occur. A cardioversion or changes in the patient’s anti-arrhythmic regimen may be required during this time. Despite these early episodes of AFib, many patients will no longer experience AFib once the heart has completely healed.
Patients will be seen in the electrophysiologist’s clinic within three to four weeks after the procedure.
How successful is this procedure?
The majority of people undergoing PVI (70 to 75 percent) benefit from the procedure, with AFib episodes being significantly reduced or eliminated entirely. Approximately 60 percent of patients will not require long-term medication therapy. Some individuals (15 to 20 percent) may require anti-arrhythmic medications after the procedure to help prevent AFib. Medications that had previously been ineffective prior to the procedure often become more effective after the ablation.
Some patients do not respond to PVI (20 to 25 percent). In those cases, other options include a repeat ablation procedure, alternative anti-arrhythmic medication or the use of a pacemaker.
Who is a candidate for the PVI procedure?
The ideal PVI candidate is an individual with symptomatic paroxysmal AFib with few coexisting cardiovascular problems. Success rates are lower in individuals with persistent or long-standing persistent AFib.
PVI is not recommended for people with an underlying, uncorrected cause for AFib (including severe heart valve disease or untreated thyroid disease).
In addition, PVI is not recommended for individuals with asymptomatic AFib that are managing the condition well with few or no medications and with heart function that is not adversely affected by the AFib.
Ultimately, this is a discussion that individuals need to have with their physicians.
What are the risks of the PVI procedure?
Most individuals who undergo a PVI will experience no adverse outcome. However, as with any invasive procedure, complications can occur. Minor complications, including bleeding or bruising at the IV site, occur in approximately 5 percent of patients. Major complications—such as stroke, perforation of the heart muscle or a heart attack—are very rare and occur in less than 1 percent of patients.
Some individuals (approximately 1 to 2 percent) have the potential to form excessive scar tissue around the pulmonary veins following the procedure. This may lead to a narrowing, or stenosis, of the vein. Usually this is asymptomatic. When severe, the stenosis could interfere with blood flow from the lungs to the heart, resulting in shortness of breath. In this case, a separate procedure may be required to open the narrowed vein.
An atreoesophageal fistula is an extremely rare complication that involves an abnormal connection (fistula) between the left atrium and the esophagus (food pipe). This complication is extremely rare (occurring less than 1 percent of the time) but has a very high mortality rate. To reduce the risk of this complication, the cardiac electrophysiologist will use a special temperature probe to carefully monitor the temperature of the esophagus at the site of the ablations while the PVI procedure is taking place.
Your cardiac electrophysiologist (heart rhythm specialist) will answer any questions and address any concerns you might have and can suggest additional sources of information.
AFib can be a big burden that has the potential to dramatically affect an individual’s quality of life. There are many options for treatment available to those with AFib. We are committed to helping you find an option that best suits your situation and your needs.
Atrial Fibrillation Clinic
Cheyenne Cardiology Associates offers a specialized clinic to treat patients with a prior history of AFib or who have been newly diagnosed with AFib.
The clinic offers a comprehensive approach to treating AFib, including:
- Educating patients about AFib
- Helping patients control their symptoms
- Helping patients manage the risk of stroke associated with AFib
- Referring patients to the local sleep lab and bariatric clinic if they need help treating obstructive sleep apnea and/or losing weight
Patients are referred to the AFib Clinic from their primary care physician’s office, the emergency department or after a hospitalization for AFib.
Appointments to the AFib Clinic are available every Tuesday and Friday.
For more information about the AFib Clinic, please call Cheyenne Cardiology Associates at (307) 637-1600 or request an appointment.