The body needs the mineral potassium to regulate muscle contraction. The heart, being a muscle, often responds to changes in potassium levels by developing irregular heartbeat or arrhythmia. Normally, potassium levels in the blood range from 3.5 to 5.0 mill-Equivalents per Liter. Symptoms from low potassium, also called hypokalemia, normally don't appear until levels drop to 2.5 mEq/L, according to "In a Page: Signs and Symptoms," by Scott Kahan. A potassium level between 3.1 and 3.3 mEq/L might not cause atrial fibrillation, but only your own doctor can determine this for you.
Definition Atrial Fibrillation
Atrial fibrillation occurs when the wiring in your heart gets its signals crossed. Electrical signals that originate in the sinus node, sometimes called the sinoatrial node, regulate your heartbeat. The SA node acts as the heart's natural pacemaker, sending signals through the heart that cause different muscles to contract in a coordinated fashion. This action pumps blood from the atria, the two top chambers of the heart, down to the ventricles, the lower chambers, and then out to the rest of your body. If you have atrial fibrillation, the atria get signals that cause them to fire too frequently, so that they quiver rather than forcefully contract.
Some people with atrial fibrillation do not notice symptoms; the problem only shows up if they have an electrocardiogram, or EKG. Between 30 and 60 percent of people with atrial fibrillation do experience symptoms, the University of California reports. Other people feel like their heart is beating too fast or in an unusual manner or flopping in their chest. They may become anxious, dizzy and sweaty. Shortness of breath or exercise intolerance may develop. Because the heart doesn't beat forcefully, blood can pool in the atria, increasing the risk of developing blood clots in the chambers. As the heart beats, these clots may be forced through the heart into the circulation. If they lodge in arteries to the brain, stroke can result.
Relation to Hypokalemia
Around 80 percent of people with potassium levels of 2.7 or lower have abnormal electrical activity on their EKG, Kahan reports. Low potassium levels can cause cells in the heart to become more excitable than normal, which may cause them to fire in an abnormal pattern, causing atrial fibrillation. Controls that normally keep this from happening are also disrupted, according to the Cleveland Clinic. These two effects cause an increase in electrical activity in areas of the heart that normally don't have spontaneous electrical activity, which can lead to atrial fibrillation.
If you have atrial fibrillation from a potassium level in the 3.1 to 3.3 mEq/L range, raising your potassium level should treat the problem. Potassium can be given in pill form or via an intravenous infusion. Low potassium levels can result from prolonged vomiting or diarrhea, diuretic use, kidney disorders or poor dietary intake, although hypokalemia from poor diet occurs rarely, according to the Mayo Clinic. Do not take potassium tablets without your doctor's approval; diagnosing and treating the underlying cause is as important as correcting the imbalance.