An arrhythmia is an abnormal heartbeat which may or may not have symptoms. An arrhythmia can cause the heart to beat irregularly, too fast, or too slow. The heart’s pumping motion is coordinated by electrical activity that moves in an organized fashion from the top of the heart (the sinus node) through the middle of the heart (the atrioventricular node) and to the bottom of the heart (through the bundle of His and Purkinje fibers). First the electrical impulse reaches the atria at the top which causes them to contract, filling the ventricles with blood. Then, the electrical impulse travels to the bottom of the heart, causing the ventricles to contract, which forces blood out of the heart and through the lungs and body. A normal heart rate runs at 60 to 100 beats per minute though athletes may naturally have lower heart rates. With an arrhythmia, this normal electrical activity does not work exactly right. Most of the time arrhythmias are not a problem and may not even be felt. Sometimes, however, arrhythmias can cause life-threatening complications. Types of arrhythmias include ventricular fibrillation, ventricular tachycardia, atrial fibrillation, atrial flutter, sick sinus syndrome, heart conduction block, long QT syndrome, Wolf-Parkinson White Syndrome, supraventricular tachycardias, and others. Arrhythmias can be caused by damage to the heart muscle (like scarring from a previous heart attack), elevated blood pressure, diabetes, heart disease, hyperthyroidism (elevated thyroid activity), smoking, drug use, stress, medications, alcohol, caffeine, and some herbal supplements. Older people with more damage to the heart are more likely to develop abnormal heart rhythms. Arrhythmias can lead to inadequate pumping function of the heart which can lead to feelings of lightheadedness, palpitations, shortness of breath and even structural changes to the heart like congestive heart failure. Risk factors for developing arrhythmias include coronary artery disease (blockages in the arteries that carry blood to the heart muscles), cardiomyopathy (abnormally dilated or enlarged walls of the heart), diseases of the valves of the heart, increasing age, genetics, thyroid problems, medications, high blood pressure, obesity, diabetes, obstructive sleep apnea, alcohol, electrolyte imbalance, and caffeine and nicotine. Having certain types of arrhythmias increases the risk of blood clots developing in the heart which can lead to strokes. The abnormal beating of the heart can also lead to heart failure either over a long time or quickly if the heart is beating too fast.
Palpitations, fluttering sensation the chest, fast heartbeat, shortness of breath, lightheadedness, slow heart beat, chest pain, dizziness, fainting
Diagnosis of an arrhythmia begins with your doctor taking a history and physical exam. Your doctor will pay particular attention to your heart sounds and pulse rate. Your doctor will want to perform an electrocardiogram (EKG). An EKG is done by placing small stickers over the chest which are attached to a machine to create a picture of the electrical activity of the heart. This picture can tell a cardiologist what type of rhythm the heart is in as well as any areas that might not be working properly. An EKG can help determine how fast your heart is going and help determine your treatment. Your doctor or cardiologist may also recommend a Holter monitor that is worn for 24 hours to record the heart’s activity or an event monitor which begins recording when the patient feels an abnormal heart beat and a pushes a button to record. Further testing can include various ways of looking at the heart muscle including echocardiograms (ultrasound of the heart), CT scan or MRI of the heart to look at the heart function and the arteries, stress tests (where the heart is induced to pump faster either by exercise or medicine while a picture of the heart’s motion is taken), and tilt table tests (where you are placed on a table lying flat then tilted upward). Your cardiologist may recommend electrophysiologic testing or “mapping” of the electrical currents in the heart which helps show the cardiologist what areas need to be treated to prevent further electrical abnormalities. This testing is done by threading thin catheters to the heart which send small electrical impulses into the heart to see where they go, which is turned into a map of the heart’s electrical pathways.
Depending on the type of arrhythmia you have, treatment may or may not be needed. If you are having symptoms from your arrhythmia, you likely need treatment. For slow heartbeats (bradycardia) without a treatable cause, your cardiologist will consider putting in a pacemaker which is a small box that helps the sinus node start the heartbeat at a good, normal pace. A pacemaker is a small battery box placed in the chest with a wire implanted into the heart where it can control the sinus node. Most pacemakers sense the normal rhythm of the heart and help the heart beat faster only when it is needed. For fast heartbeats, the treatments are much more varied. First, your doctor will likely try vagal maneuvers like holding the breath or coughing to see if the fast heart rate can be slowed. Another treatment for fast heartbeats is medications that can either control the rate of the heartbeat or the rhythm including beta-blockers and calcium channel blockers. Certain medications may also be used to try to chemically change the heart rhythm to a normal rhythm, so-called “chemical cardiversion”. Electrical cardioversion involves shocking the heart with an electrical current to reset the electrical activity of the heart (after you have medication to help you relax and minimize any associated pain). If you are kept in the hospital due to fast heart beat, you will likely be placed on telemetry which are stickers placed on the chest attached to a machine to monitor your heart rate. If a source of your abnormal heart beat is discovered through electrical mapping of the heart, your cardiologist may be able to lightly burn the abnormal cells causing the alternate electrical pathway and stop the abnormal rhythm, a procedure called ablation. Some heart arrhythmias may require implantable devices including pacemakers (as described above) or an implanted cardioverter-defibrillator (ICD) which detects abnormal heart rhythms and corrects ones which are dangerous by delivering an electric shock to reset the heart’s electrical system. Some implantable devices are a combination of pacemakers and ICDs. If coronary artery disease is the cause of your arrhythmia, your doctor may recommend an angiogram. During this procedure, a thin wire is placed in one of the blood vessels in the leg or wrist and fed up to the heart. The cardiologist then injects dye through that small wire and takes pictures of the arteries of the heart. If vessels are found which are too small, the cardiologist may be able to either use small balloons to open them or place stents (tube-shaped wire meshes) which helps keep the arteries open. Surgical options may also be available to treat arrhythmias. One surgery is called the Maze procedure (a procedure during which a series of small incisions are made in the atrium to create tiny scars that will impede the abnormal electrical circuit. The Maze procedure is very successful, but requires open heart surgery. If the cause of your abnormal heart rhythm is an aneurysm or bulge of an artery supplying the heart with blood, open heart surgery to correct that abnormality can also eliminate the arrhythmia. If heart attacks or poor blood supply are the cause of your arrhythmia, you may require coronary artery bypass surgery where narrowed parts of vessels are bypassed with healthy, open vessels to supply blood to all parts of the heart. You should discuss all of your diagnostic and treatment options with your doctor or cardiologist.
