In our Ask a Doc series, we sit down with physicians and other clinical experts across our networks, including at Allegheny Health Network, for a chat on an important health topic. In this edition, we’re talking with Dr. Amit Thosani about the risks, causes and treatments for atrial fibrillation.
Atrial fibrillation, sometimes called AF or AFib, is an irregular heart rhythm from the top chambers of the heart. People experiencing AF — about 2.7 million Americans according to the American Heart Association — often describe it as a fluttering or quivering sensation in the chest. Most cases are diagnosed after age 65, and women tend to be diagnosed between five and eight years later than men (closer to age 70).
Amanda Changuris (AC): Dr. Amit Thosani, as a clinical cardiac electrophysiology specialist with Allegheny Health Network, what kind of symptoms do you see in patients diagnosed with AF?
Dr. Amit Thosani (AT): Patients experience AF differently; they may have palpitations, heart racing, shortness of breath, fatigue or a general sense of being unwell. Patients may have some combination of multiple symptoms. There is also a subset of patients who don’t have symptoms, so they may not know they have AF.
If you’re experiencing symptoms like these, you’ll want to see your doctor so he or she can help you figure out what’s going on.
AC: Why is AF so concerning? What can happen as a result of that fluttering feeling?
AT: There are two main risks related to AF. First and most importantly, AF increases the risk of stroke, which is our biggest concern. Secondly, symptoms caused by AF can reduce a patient’s quality of life.
AC: From what I understand, there are a few varieties of atrial fibrillation. Can you describe those for me?
AT: Atrial fibrillation can have a number of different patterns.
Generally speaking, when people first are diagnosed with atrial fibrillation, they tend to be paroxysmal and over time the episodes become more frequent. Often, the individual episodes may become longer in duration or more symptomatic until the point where AF becomes persistent and stays unless treatment is offered to restore the heart’s normal rhythm.
Our study of the natural history of AF and treatment outcomes show that there is likely a time period in which people respond better to treatment, either when they are paroxysmal or early in the persistent stage. However, many patients who are persistent or long-standing persistent may still benefit from restoration and maintenance of normal sinus rhythm.
AC: Evaluating and reducing a patient’s stroke risk sounds like a top priority for treatment. How do you start that process?
AT: Our first step involves assessing a patient’s risk of stroke, which depends not only on having AF, but also on other cardiovascular risk factors; for example, heart failure, hypertension, prior stroke or diabetes. After assessing a patient’s individual stroke risk, we may recommend treatment with a blood thinner to reduce the risk of stroke. Blood thinners, also known as anticoagulants, include warfarin or newer medications that are available now — rivaroxaban (Xarelto), apixiban (Eliquis), dabigatran (Pradaxa) or edoxaban (Savaysa).
Warfarin has been used for years, has been proven to be effective, is inexpensive, and for many years was the best available option we had for reducing stroke risk related to AF. One challenge, however, is that it’s often difficult to maintain warfarin in what we call the therapeutic range. We want it to keep the blood thin enough to reduce the risk of stroke without significantly increasing the risk of bleeding. In our best clinical trials, the time that patients who take warfarin are in the therapeutic range is usually at best about 60 percent. That means that up to 40 percent of the time, patients may not be adequately anticoagulated and thus not adequately protected from the risk of having a stroke. Warfarin also interacts with different foods and medications, and individual doses must be tailored to each patient.
The newer medications work differently and their blood thinning effect is much more predictable, which means that unlike warfarin, they don’t require frequent blood testing. They also tend to have fewer drug interactions.
The other potential advantage to the newer blood thinners is that the risk of a bleeding type of stroke — bleeding in the brain — is lower with all of the newer medications than it is with warfarin. There’s still a risk of bleeding on any blood thinner, but the lower risk of a bleeding type of stroke is an important consideration.
AT: Patients often seek treatment because the symptoms of atrial fibrillation result in a decreased quality of life.
We have been fortunate to build a comprehensive Center for Atrial Fibrillation. Our program consists of talented cardiac electrophysiologists, cardiac surgeons, nurse practitioners and specialized technical support staff. We strive to provide personalized care for each of our patients, and we are always available.
We can offer various treatment options for patients suffering from symptoms due to AF, which range from medications to help control the heart rate, to stronger medications called antiarrhythmic medications, which help control the heart rhythm, to procedures to restore and maintain a normal heart rhythm.
One such procedure is called a cardioversion. A cardioversion restores the heart’s normal rhythm with a controlled electric shock while the patient is asleep. In some cases a cardioversion can be performed with medications without an electric shock. We also offer more advanced treatment options known as AF ablation procedures, which are designed to minimize the risk of recurrent atrial fibrillation by eliminating the triggers and, in some cases, the substrate for the arrhythmia.
AC: What are those triggers?
AT: The most common reason people have atrial fibrillation is because of triggers from structures called the pulmonary veins.
The job of those pulmonary veins is to return oxygen-rich blood from the lungs to the heart so the heart can pump it out to the body. The pulmonary veins contain muscle sleeves that can fire at random and set the heart off its normal rhythm.
This physiology is the foundation for our ablation procedures. We use either radio frequency energy or cryoablation — freezing the veins — to electrically uncouple those veins so when they are active and firing, they don’t disrupt the heart’s normal rhythm.
AT: These catheter ablation procedures are minimally invasive — there are no incisions or stitches; just needle punctures in the veins of the groin. We advance long wires called catheters into the heart and electrically uncouple those pulmonary veins from the heart. After ablation, when those extra beats fire, they don’t reach the main body of the heart and cause atrial fibrillation.
AC: Does AF often occur alongside other health issues or conditions?
AT: Atrial fibrillation is associated with a number of issues. Obesity is one, obstructive sleep apnea — which is a treatable condition — is another driver of atrial fibrillation. So are high blood pressure, coronary artery disease, valvular heart disease, diabetes and lung disease. Some patients may not have any of these risk factors but still have atrial fibrillation.
AC: So if I have that kind of history or condition, I’ll want to be extra aware of AF. Are there steps I can take to reduce my risk even if I’m relatively healthy?
AT: Maintaining a healthy lifestyle for general cardiovascular health is important, not just for preventing atrial fibrillation but other forms of heart disease, as well.
As with many medical conditions, disease prevention is the best way to avoid the need for treatment. Be sure you have a primary care physician, have your recommended medical checkups, and maintain a healthy diet and lifestyle.
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