What to know about variable heart rhythms and AFib
An Ohio State cardiac electrophysiologist shares what to know about heart rhythms and AFib.
Atrial fibrillation is a rapid and irregular heart rhythm that originates from the top chambers of the heart called the atria. The rapid rate in the atria causes the bottom chambers of the heart, the ventricles, to also beat rapidly and irregularly. In a manner similar to other pumps, the heart pump does not work as efficiently as it should when it is beating rapidly and irregularly.
Atrial fibrillation is the most common heart rhythm problem. Nearly three million people in the United States have atrial fibrillation, and this number is increasing. While it usually occurs in patients who have other heart disease, it also is frequently found in patients who do not have heart disease. With increasing age, atrial fibrillation becomes more common, roughly doubling with each 10 years of life. In other words, three percent of people in their 60s, about six percent of people in their 70s and about 10 percent of people in their 80s will develop atrial fibrillation.
In many patients, an episode of atrial fibrillation will stop on its own, and this is termed paroxysmal atrial fibrillation. For other patients, the atrial fibrillation will not stop unless the patient is given a medication, called an antiarrhythmic medication, or an electrical cardioversion (an electrical shock to the heart) to interrupt the atrial fibrillation. This type of atrial fibrillation is termed persistent atrial fibrillation. In general, patients with persistent atrial fibrillation have a "tougher" variety of atrial fibrillation and tend to be less responsive to medications than patients with paroxysmal atrial fibrillation.
There are many factors that can contribute to atrial fibrillation, including:
In nearly all patients with atrial fibrillation, a key cause of atrial fibrillation is electrical short circuits or abnormal electrical firings from within the heart. These rapid electrical firings can lead to an episode of atrial fibrillation. Using special electrophysiology catheters (catheters that record electrical signals from within the heart) it has been found that many of these electrical firings arise from within or near the pulmonary veins. The pulmonary veins are blood vessels that carry blood from the lungs back to the heart and join the heart in the left atrium.
Atrial fibrillation often causes symptoms such as:
Ohio State's Ross Heart Hospital has a specialized team of heart rhythm specialists, called electrophysiologists, and more than 100 nursing personnel who specialize in caring for patients with heart rhythm problems. Our electrophysiology program is the largest program in Ohio, and one of the top in the nation, with extensive experience in managing a wide spectrum of heart rhythm problems.
Aaron's irregular heartbeat increasingly caused him to miss out on things that were important to him, time with his wife and three young daughters.
Watch his story.
The first step in the diagnosis of atrial fibrillation is a medical history and physical examination by your doctor. Sometimes, when patients experience their first episode of atrial fibrillation, they feel the irregular beats of their heart and seek help at an Emergency Department. Obtaining an electrocardiogram (EKG/ECG), an electrical recording of the heart, while the patient is experiencing their symptoms is one of the most reliable and most common ways of first diagnosing atrial fibrillation.
If you have not had an EKG/ECG showing atrial fibrillation, other methods to diagnosis atrial fibrillation involve recording the heart rhythm at the time of your symptoms. These recordings are obtained as an outpatient and include:
Holter monitor – A portable, battery-operated EKG/ECG that is worn for a day or two and provides your physician with continuous data about the electrical activity of your heart.
Cardiac event monitor – A small device that is worn for longer periods of time (weeks to months) to record the heart rhythms.
Physicians at Ohio State design a specific, personalized plan for each of our patients. This plan will consider your medical problems, the health of your heart and your goals. In general, the atrial fibrillation plan will consider three major components: prevention of blood clots and stroke; controlling your heart rate; and controlling your heart rhythm.
Prevention of blood clots and stroke
During atrial fibrillation, there is no organized vigorous contraction of the top chambers of the heart (the atria) and so blood clots may form within the heart chamber. This increases the chances that the blood clot may travel from the heart to the brain resulting in a stroke, which is permanent damage to part of the brain.
Even though a patient may have a diagnosis of atrial fibrillation, the risk of stroke varies greatly from one patient to another. Your physician will discuss with you whether your risk of stroke is high enough to warrant the use of an anticoagulant (blood thinner) such as warfarin (Coumadin) or if a different therapy, such as aspirin, is more appropriate.
Controlling heart rate
For many patients, symptoms related to atrial fibrillation are due to a rapid heart rate. Controlling your heart rate may help to minimize your atrial fibrillation symptoms and can be done through the use of medications such as beta blockers, calcium channel blockers and digoxin. These medications slow your heart rate when you are in atrial fibrillation. Patients often use a monitoring device, such as a Holter monitor or cardiac event monitor, to ensure that their heart rate is being controlled.
It is important to note that medications used to control heart rate are unlikely to reduce or eliminate the episodes of atrial fibrillation. In other words, these medications are designed to reduce the heart rate but not to control the heart rhythm, so these medications are unlikely to reduce the occurrence of atrial fibrillation.
For some patients, treating the heart rate but not eliminating the atrial fibrillation heart rhythm will be the proper therapy. This approach is called rate control.
Controlling heart rhythm
There are many treatment options (medications, cardiac catheterization or surgery) that treat atrial fibrillation by preventing recurrences of the atrial fibrillation and restoring normal rhythm. These therapies are called rhythm control and treatment options include:
Antiarrhythmic medications – These are medications specifically designed to help restore and to maintain normal rhythm by preventing recurrences of atrial fibrillation. The majority of patients will require daily medications, but rarely, some can be managed with "Pill-in-the-Pocket." This treatment is based on the concept that because the episodes of atrial fibrillation are so infrequent and because there are no other significant heart problems, the patient can take an antiarrhythmic medication soon after the atrial fibrillation begins. In this manner, the hope is that the medication will help stop the episode of atrial fibrillation quickly. If this is a successful method, then the patient will not need to take medicine on a daily basis, but only at the time of their infrequent episodes of atrial fibrillation. This approach is not suitable for most patients.
Electrical cardioversion – An electrical shock is delivered to the heart to convert the heart rhythm to normal. The electrical shock is quite successful in restoring normal rhythm, but the shock does not have any lasting effect to prevent recurrences of the atrial fibrillation. Patients will often require an antiarrhythmic medication or catheter ablation procedure.
Catheter ablation – An ablation therapy to permanently eliminate atrial fibrillation by burning away the electrical short circuits that are the root cause of the atrial fibrillation. This procedure is performed through a small hole in the leg vein that involves inserting catheters – thin, flexible wires – into a blood vessel, and winding the catheter into the heart. By use of a technique called radiofrequency ablation, energy in the radio wave frequency is delivered through the tip of the catheter to eliminate (or ablate) the site of the atrial fibrillation. Another ablation technique is the use of cryoablation, an ultra-cold substance that freezes the site of the atrial fibrillation.
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