What Is Arrhythmia?

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Cardiac arrhythmia (abnormal heart rhythm or dysrhythmia) is characterized by a heartbeat that loses its normal rhythm. Cardiac arrhythmias that require medical attention happen when the heart's electrical system short-circuits and seriously disrupts the natural rhythm of a beating heart.

The term "arrhythmia" broadly describes any irregular cardiac rhythm, such as heartbeats that are too fast (tachycardia), slower than usual (bradycardia), or erratic and uncoordinated (fibrillation).

There are many different types of arrhythmia. Depending on the type, irregular heartbeats can be healthy and harmless or potentially life-threatening and deadly.

Read on to learn about different types of cardiac arrhythmia, how to tell when abnormal heart rhythms are serious and require medical attention, which treatment options help fix various arrhythmias, and if worrisome heartbeat irregularities can be cured. 

Man getting heart rate measured

izusek / Getty Images

Types of Arrhythmia

Cardiac arrhythmia types are typically categorized based on whether rhythmic irregularities start in the heart's upper or lower chambers; there are two upper chambers (the left atrium and the right atrium) and two lower chambers (the left ventricle and the right ventricle).

Ventricular Arrhythmia

Ventricular arrhythmias are abnormal cardiac rhythms that start in the heart's lower chambers, known as ventricles.

Some common types of ventricular arrhythmia include:

Supraventricular Arrhythmia

Supraventricular arrhythmias are abnormal rhythms originating in the heart's upper chambers (the atria).

Types of supraventricular arrhythmias include:

Bradycardia (Slow Heart Rate)

"Brady-" is a prefix that denotes slowness in medical terms such as "bradycardia" or "bradyarrhythmia" (slow resting heart rate). These words are used interchangeably to describe arrhythmias characterized by an abnormally slow heart rate below 60 beats per minute.

There are several different types of bradycardias or bradyarrhythmias, such as: 

What Does Tachycardia Mean?

Tachycardia is a medical term that describes rapid heartbeats above 100 beats per minute.

Arrhythmia Symptoms

Although slightly irregular heart rhythms often go unnoticed and are asymptomatic, some classic arrhythmia symptoms include:

  • Palpitations
  • Light-headedness (presyncope)
  • Fainting (syncope)
  • Chest pain
  • Cardiac arrest
  • Rapid heartbeat
  • Sweating
  • Alternating fast and slow heart rate
  • Shortness of breath
  • Anxiety

Anyone experiencing heart arrhythmia symptoms should speak to a healthcare provider promptly, or call 911 immediately if it's an emergency.

What Causes an Irregular Heartbeat?

Many factors can cause arrhythmia. For example, anxiety, daily stressors, or anything that triggers the fight-or-flight stress response can speed up your heart rate and cause tachycardia. Other common causes of irregular heartbeats associated with cardiac arrhythmia include:

  • Autonomic imbalance
  • Heart disease
  • Overstimulation of the vagus nerve
  • Drugs that trigger or exacerbate arrhythmias
  • Electrolyte or metabolic disorders
  • Genetic disorders

Is Arrhythmia Always Serious?

Arrhythmia is not always serious. The seriousness of a cardiac arrhythmia depends on the type. If arrhythmias cause irregular heartbeats consistently, they can weaken or damage the heart. This may cause serious health outcomes.

Testing to Diagnose Arrhythmia

Cardiac arrhythmias are typically diagnosed using technological devices that monitor and record heart rhythms, such as an electrocardiogram. In addition to medical history and physical exam, the following heart-monitoring tools are used to perform diagnostic tests for arrhythmia:

Heart Arrhythmia Treatment

How cardiac arrythmia is treated depends on the type of arrhythmia and its seriousness. Some types of arrhythmia aren't serious and don't require any treatment, whereas others require immediate medical attention.

In many cases, cardiac arrhythmias are fixable. Some common heart arrhythmia treatment options include:

Living a Healthy Life With Arrhythmia

The following are lifestyle changes that can improve your chances of living a healthy life with arrhythmia:

Outlook for Heart Arrhythmia

In general, the outlook for heart arrhythmia is good. Everyone experiences irregular heartbeats or abnormal heart rhythms from time to time. That said, some types of heart arrhythmia can be fatal within minutes. Call 911 and seek immediate medical attention if someone with a cardiac arrhythmia experiences any signs and symptoms of a heart attack.


"Arrhythmia" is a broad term used to describe the loss of normal rhythm. Abnormal heart rhythms characterize cardiac arrhythmias. There are many different types of heart arrhythmia. Most arrhythmias aren't life-threatening, but some can be lethal. Ventricular fibrillation is the most serious and potentially fatal arrhythmia. VF requires immediate treatment, such as CPR (cardiopulmonary resuscitation) and a defibrillator.

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By Christopher Bergland
Christopher Bergland is a retired ultra-endurance athlete turned medical writer and science reporter.