An arrhythmia describes an irregular heartbeat. With this condition, a person’s heart may beat too quickly, too slowly, too early, or with an irregular rhythm.
Arrhythmias occur when the electrical signals that coordinate heartbeats are not working correctly. An irregular heartbeat may feel like a racing heart or fluttering.
Many heart arrhythmias are harmless. However, if they are highly irregular or result from a weak or damaged heart, arrhythmias can cause severe and potentially fatal symptoms and complications.
In this article, we define arrhythmia, as well as its causes and symptoms. We also explain the possible treatments and different types.
What is arrhythmia?
A person with arrhythmia may experience chest pain.
Cardiac arrhythmia refers to a group of conditions that cause the heart to beat irregular, too slowly, or too quickly.
There are several categories of arrhythmia, including:
bradycardia, or a slow heartbeat
tachycardia, or a fast heartbeat
irregular heartbeat, also known as a flutter or fibrillation
early heartbeat, or a premature contraction
Most arrhythmias are not severe and do not cause complications. Some, however, can increase the risk of stroke or cardiac arrest.
Some people may hear doctors use the word “dysrhythmia” when referring to their irregular heartbeat. The words arrhythmia and dysrhythmia mean the same, but the word arrhythmia is more prevalent.
What is a normal heartbeat?
Doctors identify a healthy heartbeat by counting the number of times the heart beats every minute (bpm) during rest. This is known as the resting heart rate.
The range for a healthy resting heart rate varies between individuals, but the American Heart Association (AHA) suggests that it is usually between 60 and 100 bpmTrusted Source.
The fitter a person is, the lower their resting heart rate becomes. Olympic athletes, for example, will usually have a resting heart rate of less than 60 bpm, because their hearts are highly efficient.
The heart should beat with a regular rhythm, consisting of double “ba-bum” beats with even spaces in between each.
One of these beats is the heart contracting to provide oxygen to blood that has already circulated, and the other involves the heart pushing oxygenated blood around the body.
A person can measure their heart rate using their pulse. This is a point at which they can feel the heartbeat through the skin. The best locations on the body for this are:
the wrists
the insides of the elbows
the side of the neck
the top of the foot
To learn more about how the heart works here.
Types
There are several types of arrhythmia, as described here:
Atrial fibrillation
This is the irregular beating of the atrial chambers, and nearly always involves tachycardia. Atrial fibrillation (A-fib) is common and mainly develops in adults over 65 years of age.
Instead of producing a single, strong contraction, the chamber fibrillates, or quivers, often producing a rapid heartbeat.
Read more on A-fib here.
Atrial flutter
While fibrillation causes many random and different quivers in the atrium, atrial flutter is usually from one area in the atrium that is not conducting properly. This produces a consistent pattern in the abnormal heart conduction.
Some people may experience both flutter and fibrillation.
Atrial flutter can be a serious condition and usually leads to fibrillation without treatment.
Supraventricular tachycardia
The condition known as supraventricular tachycardia (SVT) refers to a rapid but rhythmically regular heartbeat. An individual can experience a burst of accelerated heartbeats that can last from a few seconds to a few hours.
Doctors classify atrial fibrillation and flutter under SVTs.
Ventricular tachycardia
This condition refers to abnormal electrical impulses that start in the ventricles and cause an abnormally fast heartbeat. This often happens if the heart has a scar from a previous heart attack.
Ventricular fibrillation
This is an irregular heart rhythm consisting of rapid, uncoordinated, and fluttering contractions of the ventricles. The ventricles do not pump blood but quiver instead.
Ventricular fibrillation can be life threatening and usually has links to heart disease. A heart attack often triggers it.
Find out more about ventricular fibrillation here.
Long QT syndrome
This syndrome refers to a heart rhythm disorder that sometimes causes rapid, uncoordinated heartbeats. This can result in fainting, which may be life threatening.
It can also occur due to genetic susceptibility or taking certain medications.
Causes
Any interruption to the electrical impulses that stimulate heart contractions may result in arrhythmia.
Several factors can cause the heart to work incorrectly, including:
alcohol abuse
diabetes
substance use disorder
drinking too much coffee
heart disease, such as congestive heart failure
high blood pressure
hyperthyroidism, or an overactive thyroid gland
stress
scarring of the heart, often due to a heart attack
smoking
certain dietary and herbal supplements
some medications
structural changes in the heart
A person with good heart health will hardly ever experience long-term arrhythmia unless they have an external trigger, such as a substance use disorder or an electric shock.
However, an underlying heart problem can mean that electrical impulses do not travel through the heart correctly. This increases the risk of arrhythmia.
Symptoms
Arrhythmia might not cause noticeable symptoms. However, a doctor may detect an arrhythmia during a routine examination or after requesting an electrocardiogram (EKG).
Even if an individual notices symptoms, it does not necessarily mean that they have a severe arrhythmia.
Some people with life threatening arrhythmias may have no symptoms, while others with symptoms may not have a severe arrhythmia.
Symptoms depend on the type of arrhythmia, as follows:
Symptoms of tachycardia
Symptoms of a rapid heartbeat include:
breathlessness
dizziness
fainting or nearly fainting
fluttering in the chest
chest pain
lightheadedness
sudden weakness
Symptoms of bradycardia
Bradycardia can cause the following symptoms:
angina, or chest pain
trouble concentrating
confusion
finding exercise more difficult than usual
dizziness
tiredness
lightheadedness
palpitations
shortness of breath
fainting or nearly fainting
profuse sweating
Symptoms of A-fib
When A-fib symptoms occur, they often have a rapid onset and may involve:
angina
breathlessness
dizziness
palpitations
fainting or nearly fainting
weakness
Complications
Some people may not experience active symptoms due to arrhythmia. However, treatment is still essential for preventing further complications, which may include stroke and heart failure.
Stroke: Atrial fibrillation means that the heart is not pumping effectively. This condition can cause blood to collect in pools and form clots.
If a clot dislodges, it may travel to a brain artery, causing a potentially fatal blockage, or stroke. Stroke can cause brain damage and require emergency treatment.
Learn more about stroke and how to prevent one occurring.
Heart failure: Prolonged tachycardia or bradycardia can result in heart failure. When the heart is failing, it cannot pump enough blood to the body and its organs. Treatment can usually help improve this.