An arrhythmia is a problem with the speed or rhythm of your heartbeat, caused by abnormal electrical activity in the heart. An arrhythmia can make your heartbeat too fast, too slow, or with an irregular rhythm.

Overview and Symptoms

Overview and Symptoms

Arrhythmia: A Common Condition

Some arrhythmias are life-threatening emergencies and can result in cardiac arrest and sudden death. When the heart doesn’t beat properly, it can’t pump blood efficiently. If your organs don’t get enough blood, they can shut down or suffer serious damage.

Most arrhythmias, however, are less serious. More than two million Americans are living with one type of arrhythmia called atrial fibrillation. Even a serious arrhythmia can often be treated with success. Most people with arrhythmias are able to live normal, healthy lives.

Types of Arrhythmias

  • Bradycardia: slow heartbeat
  • Tachycardia: fast heartbeat
  • Other conditions that reflect abnormal electrical activity and an irregular heart rhythm include:
  • Atrial fibrillation
  • Brugada syndrome
  • Long QT syndrome
  • Heart palpitations
  • Sudden cardiac arrest or cardiac death
  • Supraventricular tachycardia
  • Syncope (fainting)
  • Wolff Parkinson White syndrome

Bradycardia and Tachycardia

Bradycardia and tachycardia, when your heart is beating too slow or too fast, respectively, may not always be serious issues. For example, people who are extremely physically fit may normally have a slow heart rate, fewer than 60 beats per minute. Sinus tachycardia, from the heart’s sinus node, is also a natural response to exercise, illness or stress.

However, both can be signs of a more serious condition. Complications of both bradycardia and tachycardia can include fainting, heart failure, and more dangerous arrhythmias. Learn more:

  • Ventricular tachycardia
  • Supraventricular tachycardia

Some people may not notice anything, but symptoms of bradycardia or tachycardia can include:

  • Dizziness or lightheadedness
  • Fainting or near-fainting spells (syncope)
  • Shortness of breath
  • Weakness or fatigue
  • Chest pain
  • Sleep disturbances
  • Confusion or visual problems
  • Heart palpitations, or heart pounding or racing
  • Cardiac arrest (in extreme cases of tachycardia)
  • Low blood pressure (bradycardia)


Treatment may not be necessary for bradycardia or tachycardia if no underlying heart disease is detected. Your doctor may simply monitor your heart rate over a period of time and/or have you undergo periodic electrocardiograms (EKG). Other treatments may include:

  • Discontinuing medications that may be slowing or raising your heart rate
  • Taking specific medications to help control your heart rate
  • Pacemaker implantation (temporary or permanent)
  • Electrical cardioversion therapy (for tachycardia)
  • Catheter ablation (for tachycardia)
  • Implantable Cardioverter Defibrillator (ICD) for more serious cases of tachycardia
Heart Palpitations

Heart palpitations are sensations that feel like your heart is pounding or racing, or even skipping beats. Palpitations can be felt in your chest, throat or neck.

Palpitations are usually harmless, but can be a sign of a more serious condition, such as an arrhythmia, that may require treatment.

Palpitations can be caused by any number of factors or triggers, including:

  • Exercise
  • Anxiety and/or stress
  • Fever
  • Caffeine, nicotine, diet pills or cocaine
  • Hyperventilation
  • Not enough oxygen in your blood
  • Medications for asthma, thyroid disease or heart disease
  • Hormone changes, such as due to pregnancy
  • Abnormal heart valve
  • Electrolyte abnormality

Typically, palpitations do not require treatment unless you are found to have another underlying heart condition: an arrhythmia, heart failure, a valve problem or blood clots. If testing does not show any underlying problems, your doctor will likely recommend ways for you to avoid the triggers of your palpitations, such as stress reduction measures or cutting out certain stimulants.

Syncope (Fainting)

Syncope, or fainting, is a transient loss of consciousness and posture:

  • Usually related to temporary insufficient blood flow to your brain
  • Usually occurring when your blood pressure is too low and your heart is not pumping sufficient oxygen to the brain
  • May happen in reaction to triggers, such as the sight of blood or emotional upset

Fainting is usually harmless and does not need to be treated. However, your doctor may want to run tests to rule out a more serious cause of fainting, such as a heart disorder (including vascular disease), cardiomyopathy, arrhythmia or valve dysfunction.

Treatment seeks to prevent syncope from recurring. Depending on the results of your tests and the underlying cause of your syncope, your treatment may include:

  • Medication: taking new medicines, such as those for high blood pressure, or making changes to your current medications if they are found to be a contributing factor
  • Wearing support stockings to improve circulation
  • Making dietary changes such as eating meals more often, but in smaller portions; increasing salt, fluid and potassium intake; and staying away from caffeine and alcohol
  • Being careful when shifting from sitting to standing
  • Elevating the head of your bed while sleeping
  • Trying to avoid triggers that may cause a fainting episode

If you have an arrhythmia, an artificial pacemaker is the most common treatment for arrhythmias that cause syncope. A pacemaker, which can be temporarily or permanently implanted under the skin in the chest wall, contains electrodes threaded into your heart that deliver electrical impulses to regulate your heartbeat.