An arrhythmia is a disorder of the heart rate (pulse) or heart rhythm, such as beating too fast (tachycardia), too slow (bradycardia), or irregularly.

Abnormal heart rhythms; Bradycardia; Tachycardia

The doctor will listen to your heart with a stethoscope and feel your pulse. Your blood pressure may be low or normal.

Heart monitoring devices are often used to identify the rhythm problem, such as a:

• Holter monitor (used for 24 hours)
• Event monitor or loop recorder (worn for 2 weeks or longer)

Other tests may be done to look at heart function:

• Coronary angiography
• ECG (electrocardiogram)
• Echocardiogram

A special test, called an electrophysiology study (EPS), is done to take a closer look at the heart's electrical system. 

When an arrhythmia is serious, you may need urgent treatment to restore a normal rhythm. This may include:

• Electrical "shock" therapy (defibrillation or cardioversion)
• Implanting a short-term heart pacemaker
• Medications given through a vein (intravenous) or by mouth

Sometimes, getting better treatment for your angina or heart failure will decrease the chance of having an arrhythmia.

Medications called anti-arrhythmic drugs may be used:

• To prevent an arrhythmia from happening again
• To keep your heart rate from becoming too fast or too slow

Some of these medicines can have side effects. Take them as prescribed by your health care provider. Do not stop taking the medicine or change the dose without first talking to your health care provider. 

Other treatments to prevent or treat abnormal heart rhythms include:

• Cardiac ablation used to destroy areas in your heart that may be causing your heart rhythm problems
• An implantable cardiac defibrillator is placed in people who are at high risk of sudden cardiac death
• Pacemaker, a device that senses when your heart is beating irregularly, too slowly, or too fast. It sends a signal to your heart that makes your heart beat at the correct pace.

The outcome depends on several factors:

• The kind of arrhythmia -- some arrhythmias may be life threatening if not treated right away, or do not respond well to treatment
• Whether you have coronary artery disease, heart failure, or valvular heart disease

Call your health care provider if:

• You develop any of the symptoms of a possible arrhythmia
• You have been diagnosed with an arrhythmia and your symptoms worsen or do not improve with treatment

Taking steps to prevent coronary artery disease may reduce your chance of developing an arrhythmia.

Epstein AE, DiMarco JP, Ellenbogen KA, Estes NA 3rd, Freedman RA, Gettes LS, et al. ACC/AHA/HRS 2008 Guidelines for Device-Based Therapy of Cardiac Rhythm Abnormalities: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Revise the ACC/AHA/NASPE 2002 Guideline Update for Implantation of Cardiac Pacemakers and Antiarrhythmia Devices): developed in collaboration with the American Association for Thoracic Surgery and Society of Thoracic Surgeons. Circulation. 2008;117:e350-e408.

Olgin SE. Approach to the patient with suspected arrhythmia. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 62.

Rubart M, Zipes DP. Genesis of cardiac arrhythmias, electrophysiologic considerations. In: Bonow RO, Mann DL, Zipes DP, Libby P, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 9th ed. Philadelphia, Pa: Saunders Elsevier;2011:chap 35.