AV nodal reentrant tachycardia (AVNRT) is a type of reentrant tachycardia (fast rhythm) of the heart. It is a supraventricular tachycardia, meaning that it originates from a location within the heart above the bundle of HIS. The term symptom (from the Greek syn = con/plus and pipto = fall, together meaning co-exist) has two similar meanings in the context of physical and mental health: Strictly, a symptom is a sensation or change in health function experienced by a patient. ... In medicine, a sign is a feature of disease as detected by the doctor during physical examination of a patient. ... The International Statistical Classification of Diseases and Related Health Problems (commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ... The following codes are used with International Statistical Classification of Diseases and Related Health Problems. ... The International Statistical Classification of Diseases and Related Health Problems (commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ... The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. ... Tachycardia is an abnormally rapid beating of the heart, defined as a resting heart rate of 100 or more beats per minute in an average adult. ... The heart and lungs, from an older edition of Grays Anatomy. ... A supraventricular tachycardia (SVT) is a rapid rhythm of the heart in which the origin of the electrical signal is either the atria or the AV node. ...

In AVNRT, the fast pathway and the slow pathway are usually both in the right atrium. The slow pathway (which is usually targeted for ablation) is located inferiorly and slightly posterior to the AV node, often following the anterior margin of the coronary sinus. The fast pathway is usually located just superior and posterior to the AV node. The atrioventricular node (abbreviated AV node) is the tissue between the atria and the ventricles of the heart, which conducts the normal electrical impulse from the atria to the ventricles. ... The atrioventricular node (abbreviated AV node) is the tissue between the atria and the ventricles of the heart, which conducts the normal electrical impulse from the atria to the ventricles. ...

Types of AVNRT

There are two types of AVNRT, called the common form and the uncommon form.

Common AVNRT

In common AVNRT, the anterograde conduction is via the slow pathway and the retrograde conduction is via the fast pathway ("slow-fast" AVNRT).

Because the retrograde conduction is via the fast pathway, stimulation of the atria (which produces the inverted P wave) will occur at the same time as stimulation of the ventricles (which causes the QRS complex). As a result, the inverted P waves may not be seen on the surface ECG since they are buried with the QRS complexes. Often the retrograde p-wave is visible, but also in continuity with the QRS complex, appearing as a "pseudo R prime" wave in lead V1 or a "pseudo S" wave in the inferior leads. ECG may also refer to the East Coast Greenway Lead II An Electrocardiogram (ECG or EKG, abbreviated from the German Elektrokardiogramm) is a graphic produced by an electrocardiograph, which records the electrical voltage in the heart in the form of a continuous strip graph. ...

Uncommon AVNRT

In uncommon AVNRT, the anterograde conduction is via the fast pathway and the retrograde conduction is via the slow pathway ("fast-slow" AVNRT). Multiple slow pathways can exist so that both anterograde and retrograde conduction are over slow pathways. ("slow-slow" AVNRT).

Because the retrograde conduction is via the slow pathway, stimulation of the atria will be delayed by the slow conduction tissue and will typically produce an inverted P wave that falls after the QRS complex on the surface ECG. ECG may also refer to the East Coast Greenway Lead II An Electrocardiogram (ECG or EKG, abbreviated from the German Elektrokardiogramm) is a graphic produced by an electrocardiograph, which records the electrical voltage in the heart in the form of a continuous strip graph. ...

Fast and slow pathways vs. accessory pathways

The fast and slow pathways should not be confused with the accessory pathways that give rise to Wolff-Parkinson-White syndrome (WPW) syndrome or atrioventricular re-entrant tachycardia (AVRT). In AVNRT, the fast and slow pathways are located within the right atrium in close proximity to the AV node and exhibit electrophysiologic properties similar to AV nodal tissue. Accessory pathways that give rise to WPW syndrome and AVRT are located in the atrioventricular valvular rings, they provide a direct connection between the atria and ventricles, and have electrophysiologic properties similar to ventricular myocardium. Wolff-Parkinson-White syndrome (WPW) is a syndrome of pre-excitation of the ventricles due to an accessory pathway known as the bundle of Kent. ...

Treatment

An episode of supraventricular tachycardia (SVT) due to AVNRT can be terminated by any action that transiently blocks the AV node. This is because the AV node is an essential portion of the reentrant circuit in AVNRT. A supraventricular tachycardia (SVT) is a rapid rhythm of the heart in which the origin of the electrical signal is either the atria or the AV node. ... The atrioventricular node (abbreviated AV node) is the tissue between the atria and the ventricles of the heart, which conducts the normal electrical impulse from the atria to the ventricles. ...

Medical therapy can be initiated with AV nodal slowing drugs such as beta blockers or calcium channel blockers. Increasing vagal tone, through measures such as carotid sinus massage, or the valsalva maneuver, can sometimes terminate the tachycardia. The vagus nerve (also called pneumogastric nerve or cranial nerve X) is the tenth of twelve paired cranial nerves, and is the only nerve that starts in the brainstem (within the medulla oblongata) and extends, through the jugular foramen, down below the head, to the abdomen. ... Arteries of the neck. ... In medicine, the Valsalva maneuver is performed by forcibly exhaling against closed lips and pinched nose, forcing air into the middle ear if the Eustachian tube is open. ...

After being diagnosed with AVNRT, patients can also undergo an electrophysiology (EP) study to confirm the diagnosis and subsequent catheter ablation of the slow pathway which effectively cures the patient of AVNRT. Catheter ablation is an invasive procedure used to remove a faulty electrical pathway from the hearts of those who are prone to developing cardiac arrhythmias such as supraventricular tachycardias (SVT) and Wolff-Parkinson-White syndrome. ...

See also

• AV Reentrant tachycardia
• Supraventricular tachycardia
• Cardiac electrophysiology
• Clinical cardiac electrophysiology