Types of Heart Rhythm Disorders

  • Atrial fibrillation – This is an irregular, fast heart rhythm in the two upper chambers of the heart.
  • Bradycardia – This is a heartbeat that is too slow.
  • Tachycardia – This is a heartbeat that is too fast.
  • Ventricular tachycardia – This is an extremely fast heartbeat.
  • Supraventricular tachycardia – This is a sudden, very fast heartbeat.
  • Ventricular fibrillation – This is a fluttering of the heart muscle that doesn’t let it pump blood.
  • Sudden cardiac arrest – This is when the heart suddenly stops beating.
  • Long QT syndrome -This is a disorder of the heart that can cause sudden abnormal rhythms of the heart.
  • Wolff-Parkinson-White (WPW) syndrome – This is a condition that causes episodes of a fast heartbeat. These are caused by an extra electrical pathway in the heart.
  • Other abnormal rhythms (arrhythmias) can be caused by pregnancy, medicine interactions, or metabolic problems.


Doctors who specifically treat heart rhythm disorders (Cardiac electrophysiologists) use results of numerous medical tests and procedures to diagnose heart rhythm defects. These tests can include:

  • Electrocardiogram (ECG). A test that records the electrical activity of the heart, shows abnormal rhythms (arrhythmias), and can sometimes detect heart muscle damage.
  • Holter monitor. A small, portable, battery-powered ECG machine worn by a person to record heartbeats over a period of 24 to 48 hours during normal activities. At the end of the time period, the monitor is returned to the doctor’s office so it can be read and evaluated.
  • Event recorder. A small, portable, battery-powered machine used by a person to record ECGs over a long period. A person may keep the recorder for several weeks. Each time symptoms are experienced, the person presses a button on the recorder to record the ECG sample. As soon as possible, this sample is transmitted to the doctor’s office for evaluation.
  • Echocardiogram (also known as an echo). A non-invasive test that uses sound waves to evaluate the heart’s chambers and valves. The echo sound waves create an image on the monitor as an ultrasound probe is passed over the heart.
  • Stress test ( also called a treadmill test or exercise ECG). A test that is given while a person walks on a treadmill or pedals a stationary bike to monitor the heart during exercise. Breathing and blood pressure rates are also monitored. A stress test may be used to detect coronary artery disease, and/or to determine safe levels of exercise following a heart attack or heart surgery.
  • Tilt table test. A test done while the person is connected to ECG and blood pressure monitors and strapped to a table that tilts the person from a lying to standing position. This test is used to determine if the person is prone to sudden drops in blood pressure or slow pulse rates with position changes.
  • Cardiac CT scan. This imaging procedure uses an X-ray machine and a computer to create a 3-dimensional pictures of the heart. Sometimes a dye is injected into the vein so that the heart arteries can be seen as well.
  • Magnetic resonance imaging (MRI) of the heart. A diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body. MRI of the heart may be used to evaluate the heart valves and major vessels, detect coronary artery disease and the extent of damage it has caused, evaluate congenital defects, and detect the presence of tumors or other abnormalities. The cardiac MRI may be used prior to other cardiac procedures such as angioplasty, stenting of the coronary arteries or cardiac or vascular surgery.
  • Magnetic resonance angiography (MRA) of the heart. A specialized type of MRI procedure used to evaluate blood vessels in the heart.
  • Electrophysiology study. A test in which insulated electric catheters are placed through the large vein in the upper leg and threaded into the heart. It is used to test the heart’s electrical system to find irregular heart rhythms.
  • Implantable loop recorder. This is a small device is put in the chest under the skin. It records heart activity when a person feels dizzy or faint.


Using cutting-edge, results-driven treatment, the high performance heart team at Parkwest Medical Center can effectively manage arrhythmias. Available treatments include:

  • Defibrillation. This is the use of a device to send a shock of electricity to the heart and make it pump regularly.
  • Medications. These can help control heart rhythm and prevent blood clots.
  • Lifestyle changes. Changes in diet or exercise can help with some heart rhythm problems.
  • Pacemaker Insertion

A small device that is implanted under the skin (most often in the shoulder area just under the collarbone) that sends electrical signals to start or regulate a slow heartbeat. A permanent pacemaker may be used to make the heart beat if the heart’s natural pacemaker (the sinus node) is not functioning properly and has developed an abnormally slow heart rate or rhythm, or if the electrical pathways are blocked.

pacemaker 1
Illustration of a pacemaker device and the location where it is placed in the chest

A newer type of pacemaker, called a biventricular pacemaker, is currently used in the treatment of ventricular dyssynchrony (irregular conduction pattern in the lower heart chambers) or heart failure. Sometimes in heart failure, the two ventricles do not pump together in a normal manner. When this happens, less blood is pumped by the heart. A biventricular pacemaker paces both ventricles at the same time, increasing the amount of blood pumped by the heart. This type of treatment is called cardiac resynchronization therapy.


  • Implantable cardioverter defibrillators (ICDs)

An implantable cardioverter defibrillator (ICD) looks very similar to a pacemaker, except that it is slightly larger. It has a generator, one or more leads, and an electrode for each lead. These components work very much like a pacemaker. However, the ICD is designed to deliver two levels of electrical energy: a low energy shock that can convert  a beating heart that is in an abnormal rhythm back to a normal heartbeat, and a high energy shock that is delivered only if the arrhythmia is so severe that the heart is only quivering instead of beating.

Illustration showing the ICD device and the location when placed in the chest

An ICD senses when the heart is beating too fast and delivers an electrical shock to convert the fast rhythm to a normal rhythm. Many devices combine a pacemaker and ICD in one unit for people who need both functions. After the shock is delivered, a “back-up” pacing mode is available if needed for a short while.

  • Catheter ablation

Catheter ablation. In this procedure, a thin tube (catheter) is put into a blood vessel in the groin. A wire is put through the catheter and sent up to the heart. A small part of the heart that is causing arrhythmia is destroyed with radiofrequency energy.