Encyclopedia / H / Heart Arrhythmia

Heart Arrhythmia


An arrhythmia is an irregular rhythm of the heartbeat.


The heart has an intricate electrical system that synchronizes its beating. Controlled by its own pacemaker (the sinoatrial, or sinus node) and a complex conduction system, the heart beats an average of 70 to 80 times a minute over 100,000 times a day. The pacemaker sends tiny electrical signals via the conduction system, triggering a molecular chain that, in only a quarter of a second, causes heart muscles to contract. (It is these tiny pulses of current that are recorded on an electrocardiogram, also known as an ECG or EKG).

The rhythmic and sequential contraction and relaxation of the upper chambers (atria) and lower chambers (ventricles) of the heart create the force that circulates the blood. If the electrical impulses controlling the heartbeat become irregular, too slow, too rapid, or if they bypass the normal conduction system, chaotic contractions may result.

Depending on the arrhythmia's duration rate, degree of regularity and its effect on blood flow and blood pressure, it may be either insignificant or life-threatening.


Irregularities in the rhythm of the heart can be caused by many things, including disease (e.g., coronary artery disease, diabetes, cardiomyopathy), medications or drugs, an aging heart, metabolic problems; such as thyroid disease, or have no evident cause.


Symptoms arise from both slow arrhythmias (bradycardia) or fast arrhythmias (tachycardia), but they may differ from person to person.

The classic symptoms of arrhythmia include; palpitations, dizziness, fainting, chest pain, and shortness of breath. Of course, some of these may not occur, even with serious arrhythmias. People may experience palpitations, such as missed beats, "skips," "thumps," "butterflies," "fluttering," or "racing.” The palpitations may come in single or multiple beats and may be felt anywhere from the stomach to the head.

People often become more aware of palpitations before going to sleep at night, particularly when they lie on the left side of the body. At this time, they are free from distractions, and the bed may act like a drum, amplifying heartbeats.


Your nurse or physician may perform blood tests, do an electrocardiogram (EKG, a recording of your heart’s electrical activity), or use a heart monitor to assess your heart rate and rhythm.


If the arryhthmia is caused by a disease, treatment of the underlying disorder is necessary.

Antiarrhythmic drugs may be used to treat rhythm disorders. Many patients tolerate antiarrhythmic medications quite well, but all of these drugs may cause side effects, so patients should report any new sensations, symptoms or difficulties to their doctor.

Although the vast majority of patients benefit from antiarrhythmic drugs, heart arrhythmias may paradoxically worsen in 5 to 10 percent of patients. For that reason and the fact that the more serious heart rhythm abnormalities occur in sick patients, antiarrhythmic drugs are often first given in the hospital, so the effects on heart rhythm can be carefully monitored. These may be measured by an electrocardiogram (EKG), Holter monitor, telemetry, and/or electrophysiology studies. Most of the time, however, these drugs can be continued safely without hospitalization.

Automatic Implantable Cardioverter-Defibrillator (AICD): In 1980, a new approach to solving arrhythmia was tested in humans. Similar to a pacemaker, the AICD includes a wallet-sized case that houses a pulse generator with electrodes or leads that connect the generator to the heart. When the device's internal computer senses a dangerous arrhythmia, it delivers a shock (a process called defibrillation), in an attempt to restore the heart's normal rhythm.

This treatment is based on the same principle as traditional cardioversion, in which two paddles that are connected to an external generator are used to convert a disordered rhythm to a normal one. With the AICD, pads equivalent to these external paddles are attached directly to the heart's surface. Your physician will help you decide if an AICD is appropriate for your specific condition.


What tests are used to monitor or test for arrhythmias?

Are there any side effects or complications with these tests?

What type of arrhythmia is it?

Is the arrhythmia potentially life-threatening?

What are the signs and symptoms that indicate a possible heart attack or serious arrhythmia coming on?

What medication would be prescribed for the arrhythmia? And what are the side effects?

What are normal PACs (premature atrial contractions)?

How many PACs become abnormal or dangerous?

What effect might exercise have on this type of arrhythmia?

What effect might alcohol have on this type of arrhythmia?

If there are no symptoms with the arrhythmia now, how often should a complete physical be done?

Should a specialist be consulted?