Originally published in the Tri-City Voice on May 9, 2017
Did Your Heart Just Skip a Beat?
Washington Township Cardiologist Explains the Dangers and Treatment Strategies for Atrial Fibrillation
When your heart beats too slowly, too rapidly or irregularly, it is known as an arrhythmia. Atrial fibrillation, often called AFib, is the most common arrhythmia in the United States. Caused by a malfunction of the heart’s electrical system, AFib occurs when the upper chambers of the heart – the atria – contract irregularly and in an uncoordinated fashion. This causes the lower chambers – the ventricles – to beat erratically and inefficiently.
“AFib is a serious condition that increases your risk for stroke, heart failure and death,” says Catherine Dao, MD, a noninvasive cardiologist with Washington Township Medical Foundation (WTMF). “Typical symptoms include palpitations, a sensation that your heart is racing or beating irregularly, chest discomfort, or shortness of breath. Many people with AFib have more vague symptoms, however, such as fatigue, low energy, lightheadedness and a reduced capacity for exercise, or they have no symptoms at all.”
Dr. Dao notes that approximately one in five strokes are due to AFib. “With AFib’s erratic heartbeat, blood can pool in the atria and form clots,” she explains. “If a clot travels to the brain, it can cause a stroke, which is why people with AFib often require blood thinners called anticoagulants. Many stroke patients were unaware that they had AFib before a stroke occurred because they did not recognize the symptoms. In addition, screening for AFib is not routinely
performed unless someone has known risk factors for AFib.”
The risk of AFib increases as people age, and the overall incidence of AFib is increasing as the U.S. population ages. Other substantial risk factors for AFib such as high blood pressure (hypertension), diabetes and obesity also are on the rise. Additional risk factors include excessive alcohol and caffeine intake, severe infection, stress, inflammation and thyroid disorders.
“AFib can be diagnosed with an electrocardiogram (ECG), which is a noninvasive test that measures the electrical activity of the heart,” Dr. Dao says. “Since AFib may not occur all the time, other people might need to wear an ambulatory ECG monitor, or ‘Holter’ monitor for days or several weeks to obtain a diagnosis. The monitor is a small, portable, battery-operated device that measures and records the heart’s rhythm continuously as the patient goes about regular daily activities.”
AFib can occur in brief, self-limited episodes, or it can be an ongoing condition. Paroxysmal AFib is an episode that terminates in less than seven days. Persistent AFib is a condition in which the abnormal heart rhythm continues for more than a week. In both cases, the faulty electrical signals and rapid heart rate begin suddenly and then stop either on their own or with treatment. AFib is
considered “permanent” when it is chronic and the normal heart rhythm cannot be restored with treatment. Both paroxysmal and persistent AFib episodes may become more frequent over time and may progress to permanent AFib.
“There are several considerations I take when treating patients with AFib,” says Dr. Dao. “First, I identify and correct reversible risk factors and manage other chronic risk factors such as diabetes and hypertension. Second, I determine their risk for developing clots and try to prevent the clots by using anticoagulants. “Warfarin is the most commonly prescribed anticoagulant,” she adds. “It is highly effective. It is available in a generic form and is not as costly as many of the newer anticoagulants that have recently come onto the market. Warfarin can be difficult for some patients to take, however, as it has a narrow therapeutic window. Too much warfarin can lead to increased bleeding; too little is not effective. It also can interact with a number of foods and drugs that affect its level. Therefore, the dose for warfarin needs to be carefully monitored. Blood
tests are used to determine the appropriate warfarin dosage. Initially, testing can be very frequent, such as once or twice a week. Once the patient’s levels are stable, testing is usually performed on a monthly basis. Several newer anticoagulants may be easier to take because they might not require such frequent monitoring and may be associated with less bleeding, but they also are far more expensive.”
According to Dr. Dao, there are two main strategies for treating the actual rhythm
disturbance that occurs during AFib. “One strategy is to keep patients out of AFib, and in ‘sinus rhythm’ – their normal heart rhythm,” she says. “This approach is preferred for patients who have
symptoms that significantly impact their quality of life, and it sometimes involves the use of antiarrhythmic medications to control the heart rhythm.”
Dr. Dao notes that in some cases, an AFib attack cannot be brought under control with medications, and a short-term treatment called an electrical cardioversion may be appropriate. The procedure involves delivering a shock to the heart via the surface of the chest wall that “resets” the heart back into sinus rhythm.
”While cardioversion can get a patient back into sinus rhythm, its effects are often temporary, as it does not address the underlying structural problem causing AFib,” she cautions. “For patients where medications and cardioversion cannot maintain sinus rhythm, I may refer them to an electrophysiologist for an ablation to restore a normal heart rhythm.”
An ablation is an invasive procedure, performed while the patient is under general anesthesia. The electrophysiologist inserts a catheter into a vein, usually in the groin, and maneuvers it up to the heart. Small electrodes are placed in the heart to locate the areas where the abnormal electrical activity originates. Radiofrequency energy is then delivered to disrupt the electrical impulses in
those malfunctioning areas.
“The other strategy involves allowing the patient to stay in AFib, but keeping their heart rate controlled,” she notes “This strategy might be more appropriate for older patients with persistent or permanent AFib who have minimal or no symptoms. In these cases, I use medications that help control the heart rate, such as beta blockers and calcium channel blockers.”
Dr. Dao takes a multidisciplinary approach to treating AFib by working with other physicians to treat factors that can contribute to the condition. “Many people with sleep apnea have higher blood pressure and are more prone to AFib,” she says. “Treating sleep apnea has been shown to lower blood pressure and reduce the recurrence of AFib. I often refer patients that I suspect
may have sleep apnea to a sleep medicine specialist to evaluate them and treat them with use of a CPAP, or continuous positive airway pressure, machine. In other cases, people with diabetes may need to work with a primary care physician or an endocrinologist to manage their blood sugar levels, since diabetes is a risk factor for AFib.”
Dr. Dao’s clinical practice is located at 2287 Mowry Avenue in Fremont. If you need help finding a physician, visit the Washington Township Medical Foundation website at www.mywtmf.com and click on the tab for “Your Doctor.”
