Treating Abnormal Heart Rhythm
You may be standing still, but your heart never stops moving. Even at rest, the average heart rate is 60 to 80 beats per minute. If you listened to your heart through a stethoscope, you would hear a steady thump-bump rhythm. But problems can develop if the cadence starts going too fast or too slow, resulting in an arrhythmia or irregular heartbeat.
An arrhythmia occurs when the heart beats too fast (tachycardia), too slow (bradycardia) or irregularly. Some common causes of abnormal heartbeats are:
- Abnormal levels of potassium or other substances
- Heart attack, or a damaged heart muscle from a past heart attack
- Congenital heart disease
- Heart failure or an enlarged heart
- Overactive thyroid gland
- Substances or drugs, including alcohol, caffeine, or stimulants such as amphetamines, beta-blocker, nicotine, or anti-depressants.
Some of the more common abnormal heart rhythms are:
- Atrial fibrillation or flutter, where the heart ventricles beat very rapidly in a regular pattern
- Atrioventricular nodal reentry tachycardia (AVNRT), where there is an abnormal electrical impulse starting in the atria
- Heart block or atrioventricular block, where the electrical signals that stimulate heart muscle contractions are blocked between the atria and the ventricles
- Multifocal atrial tachycardia, where multiple locations in the atria fire signals at the same time
- Paroxysmal supraventricular tachycardia, where the heart beats rapidly, starting in the part of the heart above the ventricles
- Sick sinus syndrome, where the sinus node – the heart’s natural pacemaker – doesn’t work properly
- Ventricular fibrillation, where the lower chambers of the heart flutter rather than beat, causing the heart to pump little or no blood
- Ventricular tachycardia, a fast heartbeat that starts in the lower chambers of the heart
- Wolff-Parkinson-White syndrome, where there is an extra electrical pathway in the heart that leads to a very fast heartbeat
Symptoms of arrhythmia can include fainting, skipped beats, dizziness, paleness, shortness of breath and sweating. An arrhythmia may be present all of the time or it may come and go. You may or may not feel symptoms when the arrhythmia is present. Or, you may only notice symptoms when you are more active. Possible complications associated with arrhythmias include chest pain and heart attack, stroke and even sudden death. That’s why it is important to seek medical help and begin treatment if you develop any symptoms of a possible arrhythmia.
Your doctor may use a number of tests to diagnose heart arrhythmia, including:
- Electrocardiogram (ECG). During an ECG, sensors (electrodes) that can detect the electrical activity of the heart are attached to the chest and sometimes to the limbs. An ECG measures the timing and duration of each electrical phase in your heartbeat.
- Holter monitor. This portable ECG device can be worn for a day or more to record heart’s activity during a person’s daily routine.
- Event monitor. For sporadic arrhythmias, this portable ECG device can be attached to the body only when an individual experiences symptoms of an arrhythmia, allowing the doctor to check heart rhythm at the time that symptoms occur.
- Echocardiogram. In this noninvasive test, a hand-held device (transducer) is placed on the chest and uses sound waves to produce images of the heart’s size, structure and motion.
Fortunately, arrhythmias can be treated a number of ways. Factors taken into account when developing a treatment program may include the nature and severity of the arrhythmia, any underlying diseases that could affect your health, age, medical history and prescribed medications for other conditions. Treatment options include lifestyle changes, medications, electronic devices, catheter ablation and surgery.
Because other heart disorders can increase your risk of developing arrhythmias, lifestyle changes such as eating a healthy diet, exercising and not smoking may be recommended. A healthy lifestyle also can help lessen the symptoms of arrhythmias.
In addition, your doctor may prescribe medicine to treat the heart rhythm disorder and lessen associated symptoms. There are more than 20 antiarrhythmic medications available in the United States. They are generally divided into four categories:
- Class I sodium-channel blockers are used to slow electrical conduction in the heart.
- Class II beta-blockers work by blocking impulses that can cause irregular heartbeats.
- Class III medicines block potassium channels by slowing electrical impulses in the heart.
- Class IV medicines block calcium channels in the heart.
All drugs work in different ways, so your doctor may prescribe a few different kinds of antiarrhythmics to find the one that works best for you.
Electronic devices such as implantable cardioverter-defibrillators (ICD) and pacemakers may be used to help maintain a normal heart rhythm. An ICD can quickly detect a life-threatening rapid heartbeat and deliver an electrical shock to the heart to restore a normal rhythm.
Two more options for treating arrhythmias include catheter ablation and maze surgery. Catheter ablation involves threading a long, flexible tube through a blood vessel into the heart where a burst of radiofrequency energy destroys a targeted area of heart tissue that was causing the arrhythmia. During maze surgery, surgeons create a “maze” of new electrical pathways in the heart to allow impulses to travel more easily.