Heart rhythm conditions

An abnormal heart beat is called an arrhythmia. It may last for a few seconds to a few hours or even days before returning to normal. Most of the time, arrhythmias are harmless and happen in healthy people free of heart disease. However, some arrhythmias can be serious or even deadly. Typical arrhythmia symptoms include palpitations, shortness of breath, fatigue, dizziness, or feeling faint, but some people with arrhythmias do not have symptoms.

Common causes

Different types of arrhythmias occur in different parts of the heart, but they are all caused by problems with the heart’s electrical system. That’s why we refer to our EPs as heart electricians. Some common causes of arrhythmia include: 

  • Structural damage to the heart such as a leaky valve or weak heart squeeze.
  • Abnormal thyroid or electrolyte levels.
  • Sleep apnea.
  • Heart blockage.
  • High blood pressure.

Types of arrhythmias

Our Heart Rhythm Team has extensive experience treating and helping adult patients manage all types of arrhythmias: 

  • Atrial fibrillation (AF or AFib) is the most common abnormal heart rhythm. In AFib, an abnormality in the heart’s electrical system causes the top chambers (called the atria) to beat so quickly and irregularly that the heart begins to quiver instead of squeeze. This abnormal heart beat decreases the amount of blood the heart can pump, which can cause a blood clot and/or stroke. Patients with AFib are five times more likely to experience a stroke than those without the arrhythmia. If AFib is not treated, it can weaken the heart and lead to a condition called heart failure.
  • Atrial flutter happens when a normal heart beat signal gets caught in a loop and spins around rapidly in the upper chamber of the heart. This leads to a very fast but steady heartbeat and can increase a patient’s risk of stroke.
  • Sick sinus syndrome (SSS) is a group of symptoms that occur when the heart’s natural pacemaker is not working properly. In SSS, the heart rate can alternate between being too slow (called bradycardia) and too fast (called tachycardia). This often happens when patients also have AFib or atrial flutter.
  • Sinus tachycardia is a normal increase in the heart rate that happens during events such as exercise, excitement, or fever. It is generally harmless, but a person experiences it while they are at rest, it may be caused by an underlying problem such as low blood count or an overactive thyroid gland. This is called inappropriate sinus tachycardia.
  • Ventricular fibrillation (VF) is the most serious arrhythmia. This dangerously fast and disorganized heartbeat can accompany a heart attack but often happens without warning. It causes the heart to stop working and deprives the body of oxygen. If not immediately treated, VF is deadly.
  • Ventricular tachycardia (VT) is an arrhythmia that occurs in the heart’s lower chambers. Because it can lead to VF and be life threatening, VT requires immediate and aggressive treatment. VT is usually seen in people with damage to their heart muscle, but it can happen in people with normal hearts too.
  • Premature contractions are extra, early, or “skipped” beats that can start in the upper chambers of the heart (called premature atrial contractions) or the lower chambers (called premature ventricular contractions). They are common and can happen in people of all ages. Premature contractions typically are not dangerous, and they don’t require treatment unless they cause symptoms.