Symptoms and Complications

When the heart beats faster than normal, it's called tachycardia. Symptoms include chest discomfort, palpitations, lightheadedness, dizziness, and sometimes fainting. When it beats slower than normal, it's called bradycardia. Bradycardia can cause fatigue, lightheadedness, dizziness, and fainting, as it tends to produce low blood pressure.

Everyone knows what it feels like to experience an occasional flutter of the heart, and usually it doesn't mean anything. But if you get chest pains or feel faint, or when checking your pulse you notice it to be irregular over a prolonged period, it's time to see a doctor.

Making the Diagnosis

The stethoscope is still a valuable instrument when it comes to detecting arrhythmias, but there are modern tests that can pinpoint the problem. The electrocardiogram (ECG) prints a graph of the heart's electrical activity using small electrodes taped to the chest. The pattern on these graphs reveals the type of arrhythmia. Since the arrhythmia might not occur at the hospital, there are portable ECGs that you can bring home. Some are constantly turned on over a specified period of time - others are turned on when you feel an arrhythmia. Some of these devices can download the heart signal data over the phone line. Certain arrhythmias may be associated with exercise; therefore you may be asked to walk on a treadmill or ride a stationary bicycle while hooked up to an ECG machine.

Electrophysiologic study (EPS) is a more elaborate test. Thin tubes are inserted into a blood vessel in the leg and guided up to the heart. They hold electrodes that can find the muscle tissue that may be over-riding the signals from the sinus node.

Treatment and Prevention

In some cases, arrhythmias are due to bad habits, like drinking too much alcohol. Breaking the habit can cure the problem. In others, the arrhythmias are a symptom of heart disease, and they won't go away unless this deeper problem is tackled. Fortunately, many people can benefit from modern medicine and especially in the area of surgery and the insertion of special electrical devices.

There are several medications that can slow down a rapid heartbeat (known as "rate control"). Beta blockers (e.g., atenolol*, metoprolol) are medications that are very useful for rate control in people with a variety of heart conditions. Often, these medications can be used for more than one purpose (i.e., rate control, high blood pressure as well as for after a heart attack). Another medication, digoxin, is derived from a substance called digitalis that has been used for arrhythmias for over 200 years.

Other medications called antiarrhythmics can convert an abnormal rhythm back to normal, and prevent it from recurring (known as "rhythm control"). Patients with atrial fibrillation are usually given the anticoagulant warfarin, which thins the blood to keep blood clots from forming and causing strokes. Recent research has shown that rate control and adequate anticoagulation are very important (perhaps even more important than rhythm control) to people with certain kinds of arrhythmias (e.g., atrial fibrillation).

Many arrhythmias can be cured outright with radiofrequency ablation. The same tubes used in EPS (see Making the Diagnosis) are inserted into the heart to send radio waves directly onto electrical pathways carrying inappropriate signals, to prevent it from triggering an abnormal heart rhythm.

Artificial pacemakers can take over the job of generating the electrical signals. Once limited to treating slow heart rates, the latest pacemakers can control fast heart rates too. Amazingly, they can run up to 15 years on one battery. Some save power by switching off when the heartbeat is normal. Most units are placed under the skin, requiring very minor surgery.

Defibrillators are devices that restart arrested hearts with jolts of electricity to the chest. Defibrillators are effective at stopping ventricular fibrillation, but since ventricular fibrillation can be fatal in less than four minutes, they are most useful when used early. Most defibrillators are external devices, but now there are automatic implantable cardiovertors/defibrillators (AICD). These miracles of miniaturization can be as small as pacemakers. They can detect a dangerous fibrillation and jolt the heart back to normality before any harm is done. As one doctor puts it, "it's like having an emergency room implanted in your chest."

*All medications have both common (generic) and brand names. The brand name is what a specific manufacturer calls the product (e.g., Tylenol®). The common name is the medical name for the medication (e.g., acetaminophen). A medication may have many brand names, but only one common name. This article lists medications by their common names. For more information on brand names, speak with your doctor or pharmacist.