Atrial Fibrillation Diagnosis

Diagnosis

Atrial fibrillation occurs when the heart's two upper chambers quiver rather than beat effectively Figure 01.

Figure 01. The heart

To beat effectively, the heart relies on an organized sequence of electrical impulses. Any deviation from this normal sequence is known as an “arrhythmia.” in the case of atrial fibrillation, the arrhythmia is one in which the heart beats too fast (tachycardia).

Atrial fibrillation can cause a feeling of a racing heart or extra heartbeats (palpitations). However, sometimes it occurs without symptoms, in which case it can be discovered during a routine physical examination. If your condition is very serious or you have other forms of heart disease, your doctor will probably refer you to a heart specialist (cardiologist) to take over your care. If left untreated, atrial fibrillation can lead to heart failure or stroke.

Atrial fibrillation is serious, but can be treated. Most patients with atrial fibrillation can lead normal lives. The heart returns to a normal rhythm in roughly 50% of people whose atrial fibrillation comes on suddenly. Whether or not someone with atrial fibrillation will require treatment depends on the severity of their symptoms and their person’s overall health, age, and lifestyle.

Experts aren’t certain what causes atrial fibrillation Table 01. In many cases, atrial fibrillation results from an enlarged upper heart chamber (atrium), which can be caused by heart failure, high blood pressure over time, or diseased heart valves. Atrial fibrillation is also a common complication of heart surgery; especially among older people. It can also be caused by such illnesses as lung disease or asthma, from alcohol abuse or street drug use (primarily “uppers”), or from certain over-the-counter herbal preparations (such as Ephedra or ginseng). Atrial fibrillation can also occur without any obvious cause.

The most common symptom of atrial fibrillation is an irregular, thumping heartbeat (heart palpitations) Table 02. The symptoms of atrial fibrillation vary because they depend on many factors, including the rate that the ventricles contract and pump blood, how well the heart is functioning, and the presence or lack of heart disease.

People often do not recognize extra heartbeats. However, feelings that your heartbeat is racing, irregular, or particularly forceful are common. Fatigue, trouble with exercise, shortness of breath, dizziness, chest pain, and overall weakness are other symptoms associated with atrial fibrillation.

Some people with atrial fibrillation never have any symptoms.

Sometimes patients with atrial fibrillation have no symptoms.

Atrial fibrillation is the most common serious heart rhythm disorder, affecting 5% to 9% of individuals over the age of 65. Although experts are not certain about what causes atrial fibrillation, a variety of factors can be involved.

• Age. Studies show that the number of people who develop atrial fibrillation doubles with each decade after age 50; about 9% of people who reach the age of 80 will have atrial fibrillation. One reason is that changes in the atria—for example, buildup of scar tissue, protein, or starch deposits, and inflammation—tend to occur naturally with aging. In addition, these changes can result from diseases that are more common in older people, such as diabetes and coronary artery or heart valve disease.
• Gender. Men are 1.5 times more likely to develop atrial fibrillation than women are, although women who develop it have a greater risk for early death.
• Heart disease. There are several heart conditions that increase the likelihood for atrial fibrillation—especially heart valve disease, heart failure, and heart attack. Others include high blood pressure, endocarditis, and cardiomyopathy. Coronary artery disease and rheumatic heart disease also increase risk.
• Other conditions. Lung disease, blood clots that form in the lungs, emphysema, and asthma also seem to affect the heart in ways that can lead to atrial fibrillation. Diabetes and thyroid disease also affect risk.
• Lifestyle factors. Other important factors that increase the likelihood of developing atrial fibrillation include cigarette smoking, alcohol abuse, and use of stimulant drugs such as cocaine, amphetamines, and even caffeine.

Your doctor will take a complete medical history to determine if your symptoms indicate atrial fibrillation. It’s important to provide your doctor with as much information as possible about your symptoms. For example, be prepared to explain your exact symptoms, when they first occurred, and if they occur all the time or just occasionally. Think about any activities that might have triggered an irregular heartbeat, such as exercise. Remember that factors that seem unimportant to you may be helpful in pinpointing the cause of your symptoms.

Your doctor will listen to your heart with a stethoscope to determine whether your heart is beating too fast or too slow, or if you have any sort of underlying heart disease. Your doctor will also want to measure your blood pressure, take your pulse, and look for signs of other diseases that can contribute to atrial fibrillation, such as alcoholism, lung disease, or thyroid problems.

Your doctor will probably order an electrocardiogram (EKG) to learn more about your heart’s rhythm and electrical impulses. An EKG can also reveal if the heart is enlarged (a factor that often leads to atrial fibrillation), and if there is any damage to the heart muscle as a result of a heart attack.

The EKG is conducted in your doctor’s office, and involves placing electrical sensors on each arm and leg and across the chest when you are lying down. The results are recorded on a sheet of paper as waves, which represent the different stages of your heartbeat.

If your doctor suspects that your condition is serious or that you have another type of disease that can worsen your arrhythmia, he or she will probably conduct further tests. Such tests can include Holter monitoring, a chest x-ray, an exercise test, or an echocardiogram.

• Holter monitor. A Holter monitor is a portable EKG machine that records heart rhythm over a period of time (usually 24 hours). It is worn under clothing and also uses electrical leads to record your heart’s impulses.
• Chest x-ray. A chest x-ray is often used to determine if the heart or vessels leading to the lungs are enlarged. It can also show calcium deposits, which indicate valve disease, scarred muscle tissue, or blocked arteries. A chest x-ray is also used to learn if there is fluid in the lungs, which indicates congestive heart failure.
• Exercise testing. An exercise test measures how well your heart functions under different levels of activity. Exercise testing involves walking on a treadmill or pedaling an exercise bicycle at various speeds and levels of intensity while your doctor measures your heart rate and rhythm and blood pressure.
• Echocardiogram. This procedure uses sound waves that are transmitted to the heart, and is essentially the same technology used in an ultrasound to observe a fetus in pregnant women. The echoes are produced when the waves are reflected back and turned into images by an instrument called a transducer. An echocardiogram provides very specific information about the size of the heart’s chambers, the valve movements (which show whether they are closing and opening properly), and any changes in the blood vessels and other structures in and around the heart.

Your doctor will conduct blood and urine laboratory tests to confirm or rule out thyroid disease and diabetes. The doctor may also ask about chronic alcohol abuse, and may run blood tests to confirm that diagnosis. A complete blood count—a test that measures the levels of red and white blood cells and platelets in your blood—can detect anemia or an infection, both of which can trigger AF. The doctor will also want to rule out diabetes and thyroid disease, as both of these conditions can increase your risk for atrial fibrillation; their presence can also help to confirm the diagnosis. The same is true for chronic alcohol abuse.

The doctor will also test to make sure your kidneys are working normally.

Because underlying heart disease is an important risk factor for atrial fibrillation, key lifestyle changes can help to keep your heart healthy. High blood pressure, coronary artery disease, heart attack, and cigarette smoking are a few of the many risk factors for atrial fibrillation. Taking charge of your heart health is essential for maintaining your overall health.

• Lower your intake of foods that are high in saturated fats, cholesterol, and trans-fatty acids. Trans-fatty acids are fats that raise cholesterol levels and are found in hydrogenated vegetable oils
• Control your weight and engage in regular physical activity (30 minutes 3 to 4 times weekly) to keep your blood pressure within a safe range
• Make sure that between 55% and 60% of your diet consists of fruits, vegetables, legumes, and whole grains
• Keep alcohol intake to a moderate level (no more than two drinks daily)
• Try not to eat more than 6 grams of salt daily
• If you smoke, it's important to stop