At the core of every healthy body is a strong, rhythmic, steady heartbeat. Atrial fibrillation is a condition that disrupts this rhythm. A glitch in the heart’s electrical system makes the upper chambers (the atria) quiver or fibrillate. This causes the lower chambers (the ventricles) to beat irregularly. Atrial fibrillation can be dangerous because it increases the risk of stroke and heart failure.
Normal Heart Rhythm vs. FibrillatioThe atrioventricular node is a part of the electrical control system of the heart that coordinates heart rate. It electrically connects the upper and lower chambers of the heart and is an area of specialized tissue that conducts the normal electrical impulse from the atria to the ventricles. The node relays the signals, so the four chambers pump blood in perfect rhythm. The normal range is 60-100 beats per minute.
In atrial fibrillation, abnormal signals fire from many areas within the atria. These chaotic signals make the upper chambers quiver rapidly. Too many signals are passed through to the ventricles. The result can be irregular contractions that cause a fast, irregular heart rate (100-175 beats per minute).
Unfortunately, many people do not experience obvious warning signs. When symptoms do occur, they often include: an uneven pulse, racing or pounding heart, feeling like the heart is fluttering, chest pain, dizziness, breathlessness, weakness, fatigue and fainting.
Causes of Atrial Fibrillation
The most common triggers are conditions that strain the heart, and can include high blood pressure, coronary artery disease and heart attacks, heart failure and problems with the heart valves. In some cases, atrial fibrillation may stem from thyroid disorders or serious infections, such as pneumonia.
In addition to heart conditions, there are several factors that increase the risk of developing atrial fibrillation including: being male and white; being over the age of 60; a family history of atrial fibrillation; obesity; lung disease; and excessive use of alcohol, nicotine or caffeine. Certain prescription drugs, such as albuterol, and illegal drugs that act as stimulants also can increase the risk.
Diagnosing Atrial Fibrillation
The surest way to detect atrial fibrillation is with an electrocardiogram, otherwise known as an EKG. This painless test records the electrical activity of the heart and reveals abnormalities in its rhythm. The test can be done in a physician’s office, or the physician may have the patient wear a device that records the heart’s activity continuously for 24 hours or longer.
If an EKG shows detects atrial fibrillation, additional tests may be ordered to learn more about what is going on inside the heart or to look for conditions that triggered the atrial fibrillation. An echocardiogram or ultrasound of the heart can show whether there is any valve damage or signs of heart failure and a stress test can show how well the heart is performing.
The most common treatment for atrial fibrillation involves resetting the heart’s rhythm or controlling the heart rate. This can be accomplished through procedures such as electrical cardioversion. In this procedure, a cardiologist delivers a brief electrical shock to the heart through paddles or patches placed on the chest. The shock stops the heart’s electrical activity for a moment. Ideally, when the heart restarts it resumes its normal rhythm. Medications may be prescribed to control heart rate. Some patients, however, may need cardiac catheterization or other surgery.
When To See a Physician
If any of the above mentioned symptoms and/or risk factors are identified, it is important to talk with a primary care physician or cardiologist. Atrial fibrillation is not always an emergency, but 911 should be called if any of these symptoms occur: severe chest pain; uneven pulse and feeling faint; and signs of a stroke, such as numbness or slurred speech. FBN
Lynn Otto, M.D., is a board-certified cardiologist and electrophysiologist at the Heart & Vascular Center of Northern Arizona. Dr. Otto specializes in the electrical activities of the heart including diagnosing and treating irregular heart rhythms and implanting and managing heart devices such as pacemakers and defibrillators.
The Heart & Vascular Center of Northern Arizona is a physician practice offering services ranging from general cardiology and the treatment of chronic heart and vascular conditions to advanced surgical techniques, including open heart surgery. The center is a partnership between Flagstaff Medical Center and Verde Valley Medical Center, with offices located in Camp Verde, Cottonwood, Flagstaff, Sedona, Williams and Winslow. For more information, visit NAHeartCare.com. To make an appointment, call 928-773-2150.