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Supraventricular tachycardia - Wikipedia, the free encyclopedia 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. This is in contrast to ventricular tachycardias, which are tachycardias that are not dependent on the atria or AV node. Supraventricular tachycardia is a general term that describes a number of different arrhythmias of the heart, each with a different mechanism of impulse maintenance. en.wikipedia.org /wiki/Supraventricular_tachycardia   (576 words)

AV nodal reentrant tachycardia - Wikipedia, the free encyclopedia AV nodal reentrant tachycardia (AVNRT) is a type of reentrant tachycardia (fast rhythm) of the heart. It is a supraventricular tachycardia, meaning that it involves the atria (upper chambers) of the heart. This is because the AV node is an essential portion of the reentrant circuit in AVNRT. en.wikipedia.org /wiki/AV_nodal_reentrant_tachycardia   (297 words)

AV Nodal Reentrant Tachycardia The atrioventricular (AV) node and the His bundle are the linchpin of the electrical circuit because normally they are the only electrical connection between the atria and ventricles. The AV node and His bundle are shown as a single one-way pathway connecting the atria to the ventricles. In individuals with a normal AV node there is only a single AV nodal pathway; the electrical impulse conducts from the SA node, through the right atrium, and then traverses the single AV node pathway to the ventricles. www.kpep.org /svtachyarrhythmias/avnrt.htm   (488 words)

Chin Med J (Taipei) 1997;59:71-7. (Atrioventricular Nodal Reentrant Tachycardia) AV nodal reentrant tachycardia was diagnosed by using previously described criteria; the atrial tachycardia and the tachycardia incorporating a paraseptal accessory pathway were excluded [8,9]. Catecholamine-sensitive AV nodal reentrant tachycardia was defined as AV nodal reentrant tachycardia which was not inducible until intravenous infusion of isoproterenol [10]. AV nodal reentrant tachycardia did not fulfill the criteria of fast-slow form or slow-fast form [6,7,13]. www.vghtpe.gov.tw /~cmj/5902/590201.htm   (3231 words)

[No title]   (Site not responding. Last check: 2007-10-24) Indeed, multiple arrhythmia mechanisms such as the presence of an accessory AV pathway, atrial tachycardia, ventricular tachycardia, or atrial flutter may be present in an individual and the accurate definition and treatment of each tachycardia is important. However, the persistence of a dual AV nodal conduction pattern or the induction of single AV nodal echo beats does not indicate that further ablation is needed as long as AVNRT cannot be induced in the presence of isoproterenol. Factors that predispose to AV block include congenital heart disease (in which the AV conduction can be inferiorly displaced), an usual orientation of the coronary sinus ostium, or a prolonged refractory period of the fast pathway at baseline. www.hrsonline.org /professional_education/learning_categories/articles/kay   (1505 words)

Catheter Ablation for Supraventricular Tachycardias: Introduction By far the most common supraventricular tachycardia in adults, AV nodal reentrant tachycardia is also one of the most easily cured rhythms encountered by the heart rhythm specialist (cardiac electrophysiologist). The AV node lies between the upper chambers of the heart (the atria) and the lower chambers of the heart, the ventricles. The AV node's normal job in your heart is two-fold: (1) to permit the electrical impulse arising in the atrium to pass to the ventricles and (2) to delay the electrical impulse slightly to allow time for blood to physically move from the atria to the ventricles. www.medtees.com /avnodalreentry.html   (2241 words)

AV Nodal Reentrant Tachycardia   What is AV nodal reentrant tachycardia? Tachycardia is the medical term for an abnormally fast heart rate. In patients with AV nodal reentrant tachycardia (AVNRT) the heart rate is generally 160 to 220 beats per minute. The catheter is directed to the area of the AV node causing the tachycardia and radio frequency waves cause a small burn in the area interrupting the circuit. www.siheartdocs.com /av_nodal_reentrant_tachycardia__.htm   (613 words)

Postgraduate Medicine: Clinical Cardiac Electrophysiology Symposium: Reentrant tachycardias However, after the beat arrives at the AV junction, the fibers in the fast pathway have sufficiently recovered to conduct the beat in a retrograde manner back to the atrium, where the impulse is again conducted to the ventricle via the newly recovered slow pathway. Unfortunately, typical AV nodal reentrant tachycardia can be mimicked by several supraventricular tachycardias, including atrial flutter, atrial tachycardia with fixed and uniform blocked conduction, reentrant tachycardia with impulses traveling down the AV node and returning to the atrium via an accessory pathway, orthodromic transmission, and automatic nonreentrant junctional tachycardia. Tachycardia via an accessory pathway is usually initiated with a ventricular premature beat, which blocks the retrograde AV node pathway, and the beat travels instead in a retrograde manner to the atrium via the accessory pathway and returns to the ventricle via the AV node. www.postgradmed.com /issues/1998/01_98/karas.htm   (2964 words)

Indian Pacing and Electrophysiology Journal - Belhassen   (Site not responding. Last check: 2007-10-24) Incremental doses of ATP (10-60mg) were administered, first in sinus rhythm and then during tachycardia induced at electrophysiologic study, to 84 patients with inducible AVNRT and to 18 control patients with inducible AV reentrant tachycardia (AVRT) and no electrophysiologic evidence of DAVNP. Thus, findings at termination of tachycardia by ATP may be useful in the noninvasive diagnosis of the mechanism of a paroxysmal supraventricular tachycardia. Therefore, AV nodal echos were considered to be present when, following a sinus complex conducted with an increased PR interval: a) a >70% increment in P-P interval was observed or b) retrograde P waves were seen at the end of the QRS complex. www.ipej.org /0301/belhassen.htm   (3260 words)

Heart Rhythm Society   (Site not responding. Last check: 2007-10-24) Thus, a study aimed simply at diagnosis might be limited to establishing the presence of an accessory AV connection and the demonstration of induction of an AV reentrant tachycardia and atrial fibrillation using a single electrode catheter in the heart or the esophagus. Repeated inductions of tachycardia are recommended in an effort to elicit bundle branch block aberration during the tachycardia to obtain diagnostic information concerning the presence and location of the accessory AV connection(s). Assuming a sustained AV reentrant tachycardia is induced, the effects of premature ventricular and atrial beats introduced during diastole may be useful in understanding, localizing, and characterizing the tachycardia circuit. www.hrsonline.org /swPositionStatementFiles/ps101035444.asp   (3969 words)

Junctional Tachycardias AV nodal reentrant tachycardia is the most common type of reentrant paroxysmal SVT, occurring in about 60% of patients with SVT. The AV nodal reentrant circuit involves the AV node and tissue in close proximity to it. Atrioventricular reentry tachycardia requires the participation of both atrium and ventricle and a piece of conducting tissue bridging the atrium and ventricles outside of the AV node. www.txai.org /edu/irregular/junctional.htm   (1310 words)

Wolff Parkinson White Syndrome Tachycardia due to the concealed tract should be considered when the QRS complex is normal and the retrograde P wave occurs well after completion of the QRS complex, out in the ST segment or even in the T wave. Patients with a reciprocating tachycardia due to an accessory AV bypass tract almost always have a VA interval of greater than 70 milliseconds measured from the onset of ventricular activation to the onset of atrial activity recorded on an esophageal lead or greater than 95 milliseconds when measured to the high-right atrium. During orthodromic AV reentrant tachycardia, the time between the ventricular and atrial potentials is short and a pathway potential may be observed. www.rjmatthewsmd.com /Definitions/wolff_parkinson_white_syndrome.htm   (9796 words)

006 The purpose of this study is to investigate the clinical and electrophysiologic characteristics in pediatric patients with AV nodal reentrant tachycardia. Forty-eight pediatric patients with AV nodal reentrant tachycardia were studied (age: 11-18 years; M/F = 25: 23) to evaluate the electrophysiologic characteristics by using atrial and ventricular incremental pacing and extrastimulation. A higher incidence of antegrade dual AV nodal pathways in adult patients with AV nodal reentrant tachycardia was demonstrated (p = 0.003). www.unepsa.org /china/ab/1299.HTM   (224 words)

AV nodal reentrant tachycardia - SJMMC, Ann Arbor, Michigan MI Excluding atrial fibrillation, atrioventricular nodal reentrant tachycardia (AVNRT) is the most common type of supraventricular tachycardia. Atrioventricular tachycardias are caused by an abnormal or extra electrical pathway in the heart, a kind of "short circuit." Electrical pathways in the heart consist of microscopic muscle fibers that conduct electrical impulses. During AV nodal reentrant tachycardia the electrical impulses continuously go around the two pathways. www.sjmercyhealth.org /111804.cfm   (305 words)

Adenosine   (Site not responding. Last check: 2007-10-24) In individuals suspected of suffering from a supraventricular tachycardia (SVT), adenosine is used to help identify the rhythm. Fast rhythms of the heart that are confined to the atria (e.g, atrial fibrillation, atrial flutter) or ventricles (e.g, monomorphic ventricular tachycardia) and do not involve the AV node as part of the re-entrant circuit are not typically effected by adenosine. Because of the effects of adenosine on AV node-dependent SVTs, adenosine is considered a class V antiarrhythmic agent. www.gogoglo.com /wiki/en/wikipedia/a/ad/adenosine.html   (390 words)

IngentaConnect Electrophysiological Characteristics of Junctional Rhythm During ...   (Site not responding. Last check: 2007-10-24) Results: In all patients with slow-fast AV nodal reentrant tachycardia, the atrial activation sequence recorded during JR was similar to that of the retrograde fast pathway, and transient retrograde conduction block during JR was found in 1 (4%) patient. In patients with slow-intermediate AV nodal reentrant tachycardia, the atrial activation sequence of the JR was similar to that of the retrograde fast pathway in 5 (45%), and to that of the retrograde intermediate pathway in 6 (55%) patients. In patients with fast-slow AV nodal reentrant tachycardia, retrograde conduction with block during JR was noted in 7 (100%) patients. www.ingentaconnect.com /content/bsc/pace/2005/00000028/00000002/art00005   (495 words)

Tachycardia (Fast Heart Rate) AV nodal reentrant tachycardia usually first causes symptoms during the teenage years to middle age. Ventricular tachycardia (VT) may last for only three beats and then spontaneously revert to a normal rhythm, or it may last for hours at a time. When either type of tachycardia occurs in someone with significant coronary artery disease, the heart may not receive enough blood to keep up with the demands of the increased heart rate. hw.healthdialog.com /kbase/topic/special/ps1684/sec9.htm   (440 words)

eMedicine - Paroxysmal Supraventricular Tachycardia : Article by Monika Gugneja, MD Because the arrhythmia does not involve the AV node, nodal blocking agents such as adenosine and verapamil are usually unsuccessful in terminating this arrhythmia. AV conduction is most commonly 2:1, which yields a ventricular rate of approximately 150 bpm (see Image 4) (Akhtar, 1984; Tintinalli, 2000; Josephson, 2001). Trohman RG: Supraventricular tachycardia: implications for the intensivist. www.emedicine.com /MED/topic1762.htm   (7314 words)

Section 8 : Supraventricular Tachycardias This is mostly used in the context of describing an unknown tachycardia. Because the mechanism depends on the AV node, we can reason that if we were to temporarily disable the AV node, this rhythm might "break," that is, convert to a sinus rhythm. The important thing to note is that these tachycardias are not dependent on the AV node for their survival. www.mauvila.com /ECG/ecg_psvt.htm   (610 words)

ECG Archive 2004   (Site not responding. Last check: 2007-10-24) Left one was ablated but the ablation of the parahisian accessory pathway was deferred to another session after discussion of the risk of AV block with the patient and her relatives. Tachycardia morphology is suggestive of VT. At EP study a sustained VT morphologically different from the above clinical tachycardia was also inducible. This is rare with atrial tachycardias and is more compatible with the presence of accessory pathways or more common at this age and sex AV nodal reentrant tachycardia. www.iranep.org /ECG_archive2004.htm   (829 words)

Characterization of subforms of AV nodal reentrant tachycardia -- Heidbüchel and Jackman 6 (4): 316 -- Europace Atrioventricular nodal reentrant tachycardia: electrophysiological characteristics of four forms and implications for the reentrant circuit. AV nodal reentrant tachycardia with unusual characteristics: lessons from radiofrequency catheter ablation. Reentrant circuits in the canine atrioventricular node during atrial and ventricular echoes: electrophysiological and histological correlation. europace.oxfordjournals.org /cgi/content/full/6/4/316   (4048 words)

Tachycardia induced tachycardia: case report of right ventricular outflow tract tachycardia and AV nodal reentrant ... Tachycardia induced tachycardia: case report of right ventricular outflow tract tachycardia and AV nodal reentrant tachycardia RVOT tachycardia was not initiated by AVNRT in the this case. Coincidence of idiopathic ventricular outflow tract tachycardia and atrioventricular nodal reentrant tachycardia heart.bmjjournals.com /cgi/content/full/81/3/321   (865 words)

eMedicine - Atrioventricular Nodal Reentry Tachycardia (AVNRT) : Article by Brian Olshansky, MD The tachycardia is initiated when an appropriately timed atrial premature complex is blocked in the fast pathway (longer refractory period) and conducts in the slow pathway (shorter refractory period) (see Image 1). The substrate for AVNRT is the presence of dual AV nodal pathways. In the presence of a wide complex tachycardia, the institution of therapy should always follow a careful review of the patient's prior cardiac history, including left ventricular function and previous electrocardiograms, which are helpful tools for defining the origin of the arrhythmia (ie, supraventricular vs ventricular). www.emedicine.com /med/topic2955.htm   (3030 words)

Tachycardia - Page 3 AV reentrant tachycardia using an accessory bypass connection. Atrial tachycardias may be focal (arising from only one place in one of the atria) or multifocal (arising from many different places in the atria). Multifocal atrial tachycardia is a condition in which there are multiple foci of activation of the atria, leading to different morphologies of the atrial activities in the EKG. heart.healthcentersonline.com /arrhythmia/tachycardia3.cfm   (803 words)

Atrial Electrogram Characteristics in Patients With and Without Atrioventricular Nodal Reentrant Tachycardia -- ...   (Site not responding. Last check: 2007-10-24) AV nodal reentrant tachycardia in the mean number of deflections of the posterior atrionodal inputs to the AV node. Anatomic reconstruction of the AV junction in AV junctional (`AV nodal') reentrant tachycardia. circ.ahajournals.org /cgi/content/full/92/1/77   (3154 words)

What you should know about Catheter Ablation The AV node is the "gate-keeper" to the lower chambers and is normally the only electrical connection between the upper and lower chambers. During atrial fibrillation, the AV node is bombarded with many electrical impulses for the atria (the abnormal wavefronts), which cause the lower chambers (ventricles) to beat rapidly and irregularly. Atrial tachycardia is due to an abnormal electrical impulse originating from a spot (focus) in the upper chambers (atria) other than the normal pacemaker center (SA node). www.brighamandwomens.org /cvcenter/Patient/catheterablation.asp   (2205 words)

The chemical structure of adenosine Chemical structure of adenosine ... In individuals suspected of suffering from a supraventricular tachycardia supraventricular tachycardia (SVT), adenosine is used to help identify the rhythm. Fast rhythms of the heart that are confined to the atria atria (ie: atrial fibrillation atrial fibrillation, atrial flutter atrial flutter) or ventricle ventricles (ie: monomorphic ventricular tachycardia monomorphic ventricular tachycardia) and do not involve the AV node as part of the re-entrant circuit are not typically effected by adenosine. Because of the effects of adenosine on AV node-dependant SVTs, adenosine is considered a class V antiarrhythmic agent antiarrhythmic agent. www.biodatabase.de /adenosine   (453 words)

AV nodal re-entrant tachycardia (AVNRT)- The Doctors Lounge(TM) Atrioventricular (AV) nodal reentrant tachycardia is the most common type (excluding atrial fibrillation) of supraventricular tachycardia. AV nodal reentrant tachycardia (AVNRT) occurs in the presence of a reentrant circuit (an abnormal or extra electrical pathway in the heart, a kind of "short circuit.") involving two anatomically and physiologically distinct pathways (fast and slow pathways) linking the right atrium to the AV node. In typical (slow-fast) AVNRT, activation spreads from the atrium to the AV node via the slow pathway and returns to the atrium via the fast pathway. www.thedoctorslounge.net /cardiology/diseases/avnrt.htm   (231 words)

Cogprints - Role of Adenosine/ATP Test in Supraventricular Tachycardia   (Site not responding. Last check: 2007-10-24) Non-invasive diagnosis of dual AV node physiology (DAVNP) in patients with AV nodal reentrant tachycardia by administration of ATP or adenosine has been reported by different authors4,5. Belhassen B, Fish R, Glikson M, Glick A, Glikson M, Eldar M. Non invasive diagnosis of dual AV node physiology in patients with AV nodal reentrant tachycardia by administration of adenosine-5'-triphosphate during sinus rhythm. Non invasive diagnosis in patients with undocumented tachycardias: value of the adenosine test to predict AV nodal reentrant tachycardia. cogprints.org /4290   (709 words)

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