Cardiac arrhythmia (patient information)

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Charmaine Patel, M.D. [2]

Cardiac arrhythmia
Overview
What are the symptoms?
What are the causes?
Who is at highest risk?
Diagnosis
When to seek urgent medical care?
Treatment options
Where to find medical care for Cardiac arrhythmia?
Prevention
What to expect (Outlook/Prognosis)?
Possible complications
Cardiac arrhythmia On the Web
Ongoing Trials at Clinical Trials.gov
Images of Cardiac arrhythmia
Videos on Cardiac arrhythmia
FDA on Cardiac arrhythmia
CDC on Cardiac arrhythmia
Cardiac arrhythmia in the news
Blogs on Cardiac arrhythmia
Directions to Hospitals Treating Cardiac arrhythmia
Risk calculators and risk factors for Cardiac arrhythmia

Overview

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

What are the symptoms of cardiac arrhythmia?

When you have an arrhythmia, your heartbeat may be:

• Too slow (bradycardia

• Too quick (tachycardia

• Irregular, uneven or skipping beats

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. Symptoms can be very mild, or they may be severe or even life-threatening.

Common symptoms that may occur when the arrhythmia is present include:

• Chest pain

• Fainting

• Light-headedness, dizziness

• Paleness

• Shortness of breath

• Sweating

What causes cardiac arrhythmia?

Normally, your heart works as a pump that brings blood to the lungs and the rest of the body.To help this happen, your heart has an electrical system that makes sure it contracts (squeezes) in an orderly way.

• The electrical impulse that signals your heart to contract begins in the sinoatrial node (also called the sinus node or SA node). This is your heart's natural pacemaker.

• The signal leaves the SA node and travels though the heart along a set electrical pathway.

• Different nerve messages signal your heart to beat slower or faster.

Arrhythmias are caused by problems with the heart's electrical conduction system.

• Abnormal extra signals may occur

• Electrical signals may be blocked or slowed

• Electrical signals travel in new or different pathways through the heart

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

• Heart disease that is present at birth (congenital)

• Heart failure or an enlarged heart

• Overactive thyroid gland

Arrhythmias may also be caused by some substances or drugs, including:

• Alcohol, caffiene, or stimulants such as amphetamines

• Beta-blockers

• Cigarette smoking

• Drugs that mimic the activity of the nervous system

• Medications used for depression or psychosis

Sometimes anti-arrhythmic medications prescribed to treat one type of arrhythmia will cause another type of arrhythmia.

Some of the more common abnormal heart rhythms are:

• Atrial fibrillation or atrial flutter

• Atrioventricular nodal reentry tachycardia (AVNRT)

• Multifocal atrial tachycardia

• Paroxysmal supraventricular tachycardia

• Heart block or atrioventricular block

• Sick sinus syndrome

• Ventricular fibrillation or ventricular tachycardia

• Wolff-Parkinson-White syndrome