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.
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 bpm.
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
There are several types of arrhythmia, as described here:
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.
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.
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.
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.
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.
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.
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
- substance use disorder
- drinking too much coffee
- heart disease, such as congestive heart failure
- high blood pressure
- hyperthyroidism, or an overactive thyroid gland
- scarring of the heart, often due to a heart attack
- 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.
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:
- fainting or nearly fainting
- fluttering in the chest
- chest pain
- sudden weakness
Symptoms of bradycardia
Bradycardia can cause the following symptoms:
- angina, or chest pain
- trouble concentrating
- finding exercise more difficult than usual
- 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:
- fainting or nearly fainting
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.
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.
Treatment for arrhythmia is only necessary if the condition is increasing the risk of more severe arrhythmia or a complication, or if the symptoms are severe.
The various arrhythmias require different treatments.
Treatments for bradycardia
If bradycardia occurs due to an underlying condition, a doctor will need to treat that condition first. If they find no underlying problem, the doctor may advise implanting a pacemaker.
A pacemaker is a small device that a doctor places under the skin of the chest or abdomen to help control abnormal heart rhythms. Pacemakers use electrical pulses to prompt the heart to beat at a regular minimum rate.
Treatments for tachycardia
There are several different treatments for tachycardia:
Vagal maneuvers: Specific movements and exercises that a person can carry out at home might stop some types of arrhythmia that start above the lower half of the heart.
Medications: These will not cure an arrhythmia but are usually effective in reducing the number of tachycardia episodes. Some medications also promote electrical conduction through the heart.
Cardioversion: The doctor may use an electric shock or medication to reset the heart to its regular rhythm.
Ablation therapy: A surgeon inserts one or more catheters into the inner heart. They place the catheters in areas of the heart that they suspect may be the source of the arrhythmia. The surgeon will then use them to destroy small sections of damaged tissue, which often corrects the arrhythmia.
Implantable cardioverter-defibrillator (ICD): A surgeon implants this near the left collarbone. The device then monitors the heart rhythm. If it detects an unusually fast rate, it stimulates the heart to return to its normal speed.
Maze procedure: During the maze procedure, a surgeon makes a series of surgical incisions in the heart. These then heal into scars and form blocks that guide the electrical impulses, helping the heart to beat efficiently.
Ventricular aneurysm surgery: Sometimes, an aneurysm, or bulge, in a blood vessel that leads to the heart can cause arrhythmia. If other treatments are not effective, a surgeon may have to remove the aneurysm.
Coronary bypass surgery: A surgeon grafts arteries or veins from elsewhere in the body on to the coronary arteries. This helps the circulation bypass any regions that have become narrow and improve the blood supply to the heart muscle.
To diagnose an arrhythmia, a doctor has to identify the unusual heartbeat and try to find its source or trigger. This will involve a detailed interview, which may touch on medical history, family history, diet, and lifestyle.
A doctor may request the following tests to support an arrhythmia diagnosis:
- blood and urine
- A Holter monitor, a wearable device to record the heart for 1–2 days
- chest X-ray
- a tilt-table test to help identify if sudden decreases in blood pressure or heart rate are the cause
- electrophysiologic testing
- heart catheterization
The following may increase a person’s risk of arrhythmia:
- being 65 years of age or older
- inherited genetic anomalies
- underlying heart problems
- hypothyroidism or hyperthyroidism
- some prescription medications and over-the-counter drugs
- uncontrolled diabetes
- obstructive sleep apnea
- electrolyte imbalances
- heavy and regular alcohol consumption
- too much caffeine
- illegal drugs
While some of these are unavoidable, a person can take a few steps to reduce their risk of arrhythmia.
These actions include staying active, avoiding the regular use of alcohol or illegal drugs, and limiting caffeine intake.
The AHA recommend at least 150 minutes of moderately intense exercise every week.