context: Atrial fibrillation, or AFib, is a quivery, fluttery heartbeat. You might also hear the doctor call it arrhythmia. It means your heart's normal rhythm is out of whack. Because your blood isn't moving well, you're more likely to have heart failure. That's when your heart can't keep up with your body's needs. Blood can also pool inside your heart and form clots. If one gets stuck in your brain, you can have a stroke. What happens in AFib? Normally, the top part of your heart (the atria) squeezes first, then the bottom part (the ventricles). The timing of these contractions is what moves the blood. When you have AFib, the electrical signals that control this process are off-kilter. Instead of working together, the atria do their own thing. More than 2 million Americans have AFib. It's more common in people 60 and older. Other heart problems can make it more likely: Heart disease due to high blood pressure Heart valve disease Heart muscle disease (cardiomyopathy) Heart defect from birth (congenital heart defect) Heart failure Past heart surgery People with certain medical conditions have a greater chance, too: Long-term lung disease (such as COPD) Overactive thyroid gland Sleep apnea Medicines (including adenosine, digitalis, and theophylline) can raise the chance of having AFib. Sometimes, it's linked to: Heavy alcohol, caffeine, or drug use Infections Genetics When your heart is in AFib, you might feel: Like your heart is racing or fluttering in your chest (palpitations) Fatigued or weak Dizzy or lightheaded Chest pain or pressure Short of breath If you have these symptoms, call your doctor and make an appointment as soon as possible. If they last more than 24 hours, go to the hospital. Sometimes it doesn't cause any symptoms. If you're at risk, talk to your doctor about your chances for having AFib, and get regular checkups. The main thing your doctor wants to see is the electrical activity in your heart. She'll probably do some tests to see what's going on. Tests for atrial fibrillation include: Blood tests to check your thyroid, liver, and kidneys Electrocardiogram ( EKG) to record how fast your heart is beating and the timing of electrical signals that pass through it. A nurse or technician will place about 12 small, sticky sensors on your chest. Wires connect them to a machine that takes the measurements. Chest X-ray to make sure lung disease isn't the cause of your problems Echocardiogram, which uses sound waves to make a video of your heart working CT scans, special X-rays that make a 3 D picture of your heart MRI, which uses magnets and radio waves to create snapshots and videos of your heart Exercise stress test to see how your heart works when you're active. You might walk on a treadmill or ride a stationary bike while wearing sensors connected to an EKG machine. And she might use some special gadgets to learn more about your heartbeat such as: Holter monitor: Your doctor may want you to wear this gadget for a few days while you go about your regular activities. It's like a mobile EKG that records data from your heart 24/7. It helps your doctor spot signs of an arrhythmia. If your AFib symptoms come and go, you may need a different kind of monitor for a longer time. Depending on how severe your symptoms are, you doctor may recommend medications, surgery, or even a pacemaker to get and keep your heart in a normal rhythm. Medication: Continue Reading Below Your doctor can give you drugs that will: Slow your heart rate and ease the strength of contractions (beta-blockers and calcium channel blockers) Bring your heart's rhythm back to normal (sodium and potassium channel blockers) Prevent blood clots ("blood thinners," or anticoagulants and antiplatelets) Medical procedures: If medications don't work, your doctor will probably try one of these to reset your heart's rhythm. Electrical cardioversion: She'll stick special pads to your chest to send an electric shock to your heart. You won't feel it because you'll be asleep under general anesthesia. Ablation: She'll make a cut in one of your blood vessels and run a small tube through it and into your heart. Then she'll use a laser, radio waves, or extreme cold to burn off the tissue on the surface of your heart that's causing the problem. This creates scar tissue that doesn't pass the off-beat signals. Maze procedure: If you're having open heart surgery for another reason, your doctor might do this. It's similar to ablation. Mini maze: This is also similar to ablation, but the doctor will make three or four small cuts in your side and put tubes, surgical tools, and a tiny camera into them. Convergent procedure: This pairs catheter ablation with a mini maze. One doctor uses radiofrequency ablation in the pulmonary vein, and a surgeon makes a small cut under your breastbone to use radiofrequency energy on the outside of your heart. Pacemaker : Will help keep your heart rate steady. If you take medicine to lower your heart rate, you may need one as a backup. You'll have minor surgery to put the small device under your skin. It runs on batteries and sends little electrical bursts to your heart when it beats too slowly. You can protect your heart by the choices you make in your daily life, too. Eat healthy food. Get plenty of fresh vegetables and fruits, along with whole grains and lean protein. Limit alcohol and caffeine. Quit smoking. It can double your risk of AFib. Stop drinking: It can raise your odds of AFib. How much depends on how much you drink. And it can affect the way your blood thinners work. Exercise. It's good for you and your heart. It helps keep your muscles strong, your blood moving, and your weight in check. It even helps you sleep. Talk to your doctor about the best activities for you, so you don't overdo it. Check labels. Over-the-counter products like cold medications could have ingredients that will speed up your heart rate.