Arrhythmia Brief Description

A condition in which the electrical signals come from the atria at a very fast and erratic rate. The ventricles contract in an irregular manner because of the erratic signals coming from the atria A condition in which the electrical signals come from the atria at a very fast and erratic rate. The ventricles contract in an irregular manner because of the erratic signals coming from the atria that activate the AV node.

Atrial Fibrillation

A condition in which the electrical signals come from the atria at a fast but regular rate, often causing the ventricles to contract faster and increase the heart rate. When the signals from the atria are coming at a faster rate than the ventricles can respond to, the ECG pattern typically (but not always) develops a signature "sawtooth" pattern, showing two or more flutter waves between each QRS complex. The number of waves between each QRS complex is expressed as a ratio, for example, a two-to-one atrial flutter means that two waves are occurring between each QRS.

Atrial Flutter

A condition in which an atrial pacemaker site above the ventricles sends out an electrical signal early. The ventricles are usually able to respond to this signal, but the result is an irregular heart rhythm, which is typically benign. PACs are common and may occur as the result of stimulants such as coffee, tea, alcohol, cigarettes, or medications.

Premature supraventricular contractions or premature atrial contractions (PAC)

A condition in which an electrical signal originates in the ventricles and causes the ventricles to contract before receiving the electrical signal from the atria. PVCs are common and typically do not cause symptoms or problems. However, if the frequency of the PVCs increases significantly, symptoms such as weakness, fatigue, dizziness, fainting, or palpitations may be experienced. Heart failure may develop.

Preventricular Contractions (PVC's)

A condition in which the sinus node sends out electrical signals too slowly. There may be alternation between too-fast and too-slow rates (tachy brady syndrome). This condition may cause symptoms if the rate becomes too slow for the body to tolerate.

Sick Sinus Syndrome

A common condition in which the heart rate varies with breathing. Sinus arrhythmia is commonly found in children; adults may often have it as well. This is a benign (not dangerous) condition.

Sinus Arrhythmia

A condition in which the heart rate is faster than normal because the sinus node is sending out electrical impulses at a rate faster than usual. Most commonly, sinus tachycardia occurs as a normal response of the heart to exercise when the heart rate increases to cope with increased energy requirements. Sinus tachycardia can be completely appropriate and normal, such as when a person is exercising vigorously. Sinus tachycardia is often temporary, also occurring when the body is under stress from strong emotions, infection, fever, hyperthyroidism, or dehydration, to name a few causes. It may cause symptoms, such as weakness, fatigue, dizziness, or palpitations, if the heart rate becomes too fast to pump an adequate supply of blood to the body. Once the stress is removed, the heart rate will return to its usual rate.

Sinus Tachycardia

A condition in which the heart rate speeds up due to abnormal tissue above the ventricles. There are several different forms of SVT arrhythmias. A couple of the more common examples include arrhythmias caused by an abnormal electrical connection between the top and bottom chambers of the heart, such as atrioventricular node reentry tachycardia also referred to as paroxysmal SVT, or atrioventricular reentry tachycardia due to an extra conduction pathway between the atria and the ventricles. If that pathway conducts signals from the atria to the ventricles, it is known as Wolff-Parkinson-White Syndrome. Another common SVT form can be caused by a site in the atria that fires rapidly called atrial tachycardia. SVT usually begins and ends rapidly, occurring in repeated periods. These arrhythmias can cause symptoms, such as weakness, fatigue, dizziness, fainting, or palpitations if the heart rate becomes too fast. They can cause shortness of breath or chest discomfort.

Supraventricular tachycardia (SVT)

Palpitations (a sensation of fluttering or irregularity of the heartbeat) Weakness Fatigue Low blood pressure Dizziness Fainting Heart failure Collapse and cardiac arrest Difficulty feeding (in babies)

Symptoms of arrhythmia

A condition in which many electrical signals are sent from the ventricles at a very fast and erratic rate. As a result, the ventricles are unable to fill with blood and pump. This rhythm is life-threatening because there is no pulse and complete loss of consciousness. A person in VF requires prompt defibrillation to restore the normal rhythm and function of the heart. It will result in sudden cardiac death if not treated within seconds.

Ventricular Fibrillation

A potentially life-threatening condition in which an electrical signal is sent from the ventricles at a very fast, but often regular rate. If the heart rate is sustained at a high rate for more than 30 seconds, symptoms, such as weakness, fatigue, dizziness, fainting, or palpitations, may be experienced. Cardiac arrest may occur. A person in VT may require an electric shock or medications to convert the rhythm back to normal sinus rhythm.

Ventricular tachycardia