SEARCH · PubMed Health

Results for “Atrioventricular Node”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 289 records · Page 16Linked to original sources

PubMed1994

Late clinical and electrophysiologic outcome of radiofrequency ablation therapy by the inferior approach in atrioventricular node reentry tachycardia.

A late electrophysiologic study was conducted in 182 of 289 patients with slow-fast atrioventricular node reentry tachycardia 81 +/- 36 days after radiofrequency ablation therapy by the inferior approach. Of these 182 patients, electrophysiologic study immediately after ablation revealed a selective modification of the slow pathway in 159, a modification of both the slow and fast pathways in 15, a modification of the fast pathway alone in 3, and failure of ablation in 5. One hundred two patients had no induction of echoes; 75 had induction of fewer than four echoes; and 5 had induction of sustained tachycardia with or without isoproterenol infusion. The late electrophysiologic study in these 182 patients revealed a persistent effect without changes in conduction properties in 161 (88%) patients. A change in conduction properties was noted in 21 patients, including 5 with resumption of slow- or fast-pathway conduction with induction of sustained tachycardia, 8 with improved fast- or slow-pathway conduction, and 8 with an additional depression of fast- or slow-pathway conduction. Of the 102 patients with no induction of echoes and the 75 patients with induction of fewer than four echoes during the immediate postablation electrophysiologic study, 5 (3 and 2, respectively) patients had induction of tachycardia. Of the 5 patients with induction of sustained tachycardia in the immediate postablation electrophysiologic study, 3 continued to have induction of sustained tachycardia; 1 had induction of echoes only; and 1 had no induction of echoes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed2005

Nonlinear modeling of the atrioventricular node physiology in atrial fibrillation.

A nonlinear model of the atrioventricular (AV) node physiology in atrial fibrillation (AF) is proposed based on three assumptions: (1) normal distribution of atrial impulses, (2) right-skewed distribution of R-R intervals, (3) increase in the refractory period of the AV node due to rapid bombardment from the atria. Simulation resulted in the following conclusions, all of which are in agreement with previous experience: (1) the entry speed of atrial impulses into the AV node in AF is inversely proportional to the ventricular rate, (2) the autocorrelation function of R-R intervals is zero at all delays, (3) a newly introduced index, sign of first difference, has a negative autocorrelation function at the first delay and zero ones at all others. In spite of its simplicity, the model is able to explain what happens in atrial premature complexes, sinus tachycardia and sinus bradycardia. Different rhythms, some of which rarely seen clinically, can be reproduced by changing input patterns or by slightly manipulating the model parameters. In order to make possible a long irregular time series of R-R interval, aperiodic changes in atrial signals are shown to be necessary. In conclusion, we proposed a simple model for the AV node physiology capable of explaining the previously known facts about AF as well as predicting interesting properties of some other supraventricular arrhythmias.

Atrial Fibrillation↗

PubMed1992

Geometrically accurate activation mapping of the atrioventricular node region during surgery.

A novel method has been developed to map activation in the triangle of Koch during surgery for cardiac arrhythmias and relate the map to anatomic landmarks. It uses a hand-held electrode mounted in a freely moving linkage that has three degrees of mechanical freedom. The movements of the linkage are sensed by a computer that continuously calculates the coordinates of the electrode. The surgeon clamps the device over the triangle of Koch after the right atrium has been opened and uses the electrode to trace the anatomic landmarks of the region that are displayed on the computer screen. The position of the electrode is displayed continuously relative to these landmarks and electrograms are recorded at known positions to generate a map. The activation sequences during sinus rhythm, atrioventricular node reentrant tachycardia, "common" and "uncommon" atrial flutter, long RP' tachycardia and retrograde conduction through paranodal pathways are presented. It is concluded that 1) the high spatial resolution reveals physiologically important areas in the maps that are 8 mm long and 3 mm wide and that these areas can be related to specific anatomic landmarks; 2) there are complex electrograms in the region that may reflect the activation of different myocardial layers; and 3) there are marked changes in conduction velocity and direction within the region.

Atrial Flutter↗

PubMed1977

De subitaneis mortibus. XXVI. Fatal electrical instabiltiy of the heart associated with benign congenital polycystic tumor of the atrioventricular node.

Benign congenital polycystic tumors of the atrioventricular (A-V) node are an unusual but not very rare cause of heart block. Two such cases are presented and discussed in conjunction with the reported experience of other. The tumor is always within and only very near the A-V node, seldom involves more than the proximal end of the His bundle, and has not been reported to occur in the sinus node. Although sudden death has been reported in conjunction with these tumors, a surprising number of other patients have lived to old age and died of causes unrelated to the A-V nodal tumor. As a corollary it is important to consider a diagnosis of A-V nodal tumor in any patient of any age who presents with otherwise unexplained heart block or syncope. From accumulated experience it appears that such patients do not tolerate electronic pacing safely and some possible explanations for this are discussed. Escape rhythm in all reported cases has been characterized by QRS complexes which are narrow and a ventricular rate which is from half to two-thirds of the sinus rate. Reasons why an A-V junctional rhythm which is 66% of sinus rate may be especially stable are discussed.

Aged↗

PubMed1993

Junctional tachycardia: a useful marker during radiofrequency ablation for atrioventricular node reentrant tachycardia.

OBJECTIVES: The aim of this study was to evaluate junctional tachycardia as a useful marker during radiofrequency ablation for atrioventricular (AV) node reentrant tachycardia. BACKGROUND: Junctional tachycardia appears to be a response of the atrioventricular node to injury and is seen during both radiofrequency AV node ablation and slow and fast pathway ablation for AV node reentrant tachycardia. We hypothesized that junctional tachycardia heralding AV node block and that associated with slow or fast pathway ablation may have different characteristics that could be useful in preventing inadvertent AV block. METHODS: Characteristics of junctional tachycardia were examined after 59 radiofrequency ablation sessions in 53 consecutive patients with a mean age (+/- SD) of 41.6 +/- 16.5 years. Type 1 junctional tachycardia was followed by transient second- or third-degree AV block (n = 5) or permanent third-degree AV block (n = 1). Type 2 junctional tachycardia was followed by normal AV conduction (n = 53). RESULTS: Fifty-one patients had typical AV node reentrant tachycardia, and two patients had atypical tachycardia. Fast pathway ablation was attempted during 6 sessions and slow pathway ablation during 53 sessions. Patients underwent 15.3 +/- 10 radiofrequency applications, with a mean duration of 24 +/- 9.7 s. Junctional tachycardia was observed an average of 2.8 +/- 1.8 times per ablation session. Type 1 junctional tachycardia had a significantly faster rate than that of type 2 (cycle length 363 +/- 44 vs. 558 +/- 116, p < 0.001). In addition, type 1 junctional tachycardia was associated with predominantly ventriculoatrial block whereas type 2 was associated with predominantly 1:1 ventriculoatrial conduction (2 of 6 vs. 47 of 53 episodes, p < 0.05). CONCLUSIONS: We conclude that junctional tachycardia leading to AV block can be recognized by a faster junctional rate and ventriculoatrial block. This is a useful marker of impending AV block during slow and fast pathway ablation.

Adult↗

PubMed1997

Atypical atrioventricular node reciprocating tachycardia masquerading as tachycardia using a left-sided accessory pathway.

OBJECTIVES: The study was performed to document that atrioventricular node reciprocating tachycardia (AVNRT) can be associated with eccentric retrograde left-sided activation, masquerading as tachycardia using a left accessory pathway. BACKGROUND: The eccentric retrograde left-sided activation during tachycardia is thought to be diagnostic of the presence of a left free wall accessory pathway. However, it is not known whether AVNRT can occur with eccentric retrograde left-sided activation. METHODS: We studied 356 patients with AVNRT who underwent catheter ablation. Retrograde atrial activation during tachycardia and ventricular pacing were determined by intracardiac recordings, including the use of a decapolar coronary sinus catheter. RESULTS: The retrograde atrial activation was eccentric in 20 patients (6%). Eight of these patients had the earliest retrograde atrial activation recorded in the lateral coronary sinus leads, and 12 had the earliest retrograde atrial activation recorded in the posterior coronary sinus leads, with the most proximal coronary sinus electrode pair straddling the coronary sinus orifice. These tachycardias were either the fast-slow or the slow-slow form of AVNRT. The slow-fast form of AVNRT was also inducible in 17 of the 20 patients. Successful ablation of the slow pathway in the right atrial septum near the coronary sinus ostium prevented the induction and clinical recurrence of reciprocating tachycardia in all patients. CONCLUSIONS: Atypical AVNRT with eccentric retrograde left-sided activation was demonstrated in 6% of all patients with AVNRT masquerading as tachycardia using a left-sided accessory pathway. Ablation of the slow pathway at the posterior aspects of the right atrial septum resulted in a cure in these patients.

Adult↗

PubMed1997

Safety and efficacy of radiofrequency modification of slow pathway conduction in children < or = 10 years of age with atrioventricular node reentrant tachycardia.

This study evaluated procedural considerations, risks, and long-term efficacy of radiofrequency modification of slow pathway conduction for treatment of atrioventricular node reentrant tachycardia in children < or = 10 years of age. Using a combined anatomic and electrographic mapping approach, modification of slow pathway conduction was achieved in 25 consecutive patients, although 4 had some form of transient atrioventricular block, indicating the need for caution in patient selection, catheter manipulation, and ablation.

Adolescent↗

PubMed1987

Effects of altering the interval between the stimulus and the reflex response in the analysis of the baroreceptor control of the sinus and atrioventricular nodes in man.

Baroreceptor control of the sinus node may be determined by raising or lowering blood pressure with intravenous bolus injections of phenylephrine or glyceryl trinitrate and calculating the slope of the linear regression between the drug induced changes in systolic blood pressure and RR interval using shift 1 coupling--namely, coupling of each systolic blood pressure value with the interval of the following cardiac cycle. To assess whether shift 1 coupling provides the best linear fit and the highest regression slope nine subjects received phenylephrine and glyceryl trinitrate injections both during spontaneous sinus rhythm and during atrial pacing to evaluate baroreflex control of the sinus and of the atrioventricular node respectively. In regression analysis of the data, for each drug injection nine different shifts (from 0 to 8) were used to couple systolic blood pressure with RR or StQ intervals. When the mean results from all subjects were compared the use of shift 1 was equal or superior to the use of any other shift for both the RR and the StQ interval responses evoked by either phenylephrine or glyceryl trinitrate. In many instances, however, the shift that provided the highest correlation and regression coefficient was different from shift 1, and the use of these best individual shifts provided results considerably different from those obtained with the standard shift 1. It is concluded that in the regression analysis of baroreflex cardiac responses to vasoactive drugs the regular use of shift 1 does not invariably provide the best estimation of baroreflex sensitivity. This is better achieved by calculating the best shift in individual responses.

Atrioventricular Node↗

PubMed1996

Electrophysiologic significance of discrete slow potentials in dual atrioventricular node physiology: implications for selective radiofrequency ablation of slow pathway conduction.

Atrioventricular (AV) node reentrant tachycardia is now routinely cured by selective radiofrequency ablation of slow AV node pathway conduction. However, debate remains concerning the optimum method for localizing the site at which radiofrequency energy should be delivered to eliminate slow-pathway conduction. Some investigators have proposed simple anatomy-guided ablations posteriorly near the ostium of the coronary sinus, whereas others suggest an electrophysiology-guided ablation using either recorded "slow potentials" or mapping of the retrograde atrial exit site of slow AV note pathway conduction when possible. To examine these issues, we systematically studied slow potentials recorded in the AV junction of patients undergoing radiofrequency catheter ablation for medically refractory AV node reentrant tachycardia. In 67 patients with the slow-fast form of AV note reentrant tachycardia, we performed detailed atrial mapping along the tricuspid annulus within the triangle of Koch. Two types of slow potentials were identified. Low-amplitude, low-frequency potentials, found in 48% of patients, were localized to the mid to posterior portions of the triangle of Koch, whereas high-amplitude, high-frequency potentials, observed in 22% of patients, were located only posteriorly near the ostium of the coronary sinus. In response to a bolus infusion of adenosine or incremental atrial pacing-induced AV node Wenckebach periodicity, the low-amplitude, low-frequency potentials showed an increased duration and further reduction in amplitude and frequency and often totally disappeared. In contrast, in spite of these maneuvers, the high-amplitude and high-frequency potentials remained unchanged. Of the 25 (37%) of 67 patients in whom the earliest retrograde atrial activation during ventriculoatrial slow AV nodal pathway conduction could be recorded, no patient exhibited low-amplitude, low-frequency potentials, and only 7 (28%) of 25 of these patients showed high-amplitude, high-frequency potentials. High-amplitude, high-frequency potentials persisted after successful radiofrequency ablation of slow pathway conduction. Fewer applications of radiofrequency energy were required for successful elimination of slow pathway conduction in patients in whom the retrograde atrial exit site of slow-pathway conduction could be localized, compared with those patients who only exhibited retrograde fast AV nodal pathway conduction. We conclude that high-amplitude, high-frequency potentials are part of atrial activity, whereas the origin of low-amplitude, low-frequency potentials is unclear and may represent either true intranodal biophysical electrical activity or merely artifact or far-field potentials. Regardless, the recording of high-amplitude or low-amplitude potentials is not required for successful ablation of slow-pathway conduction, although the ability to localize the retrograde atrial exit of slow-pathway conduction may assist in the ablation procedure.

Adolescent↗

PubMed2004

Paraseptal accessory connections in the proximity of the atrioventricular node and the His bundle. Additional observations in relation to the ablation technique in a high risk area.

INTRODUCTION: Paraseptal pathways, namely, accessory connections (AC) in the vicinity of the atrioventricular node (AVN) and the bundle of His, are associated with a high risk of complete atrioventricular block (AVB) during transcatheter radiofrequency ablation (RFA) in the Electrophysiology Laboratory. In previously reported series of ablation of paraseptal ACs, the coexistence of multiple ACs in this high-risk region has rarely been mentioned. METHODS AND RESULTS: We studied 15 patients undergoing RFA of paraseptal ACs 2 of whom had dual pathways with an additional midseptal pathway revealed after the elimination of the anteroseptal target AC. The fundamental goal of the pre-ablation electrophysiological mapping was the clear-cut determination of anatomical site with His bundle recording activity. This required unique pharmacological and programmed electrical stimulation manipulations in 8 patients in whom His bundle recording activity was only temporarily possible. After identifying the corresponding His bundle site, special attention was given to the ablation catheter being situated at least 3 mm away, thus recording minimal or no His bundle activity. Additional precautions were taken so that the delivered therapy was of minimal duration and powered by temperature regulation with immediate interruption in case of AVB or nodal rhythm appearance. With this therapeutic approach, 16 of the 17 paraseptal ACs were ablated successfully with the inadvertent induction of AVB in only 1 patient. In the patient with persistent ventricular preexcitation after the ablation session, modification of both the AC and the AVN was noted so that the previously easily induced reciprocating atrioventricular tachycardia was no longer so, using programmed stimulation. CONCLUSION: Transcatheter radiofrequency ablation is a feasible and effective radical therapy for patients with paraseptal ACs, provided the His bundle site has first been clearly defined and the coexistence of other nearby tracts has been excluded.

Adolescent↗

PubMed1989

[Clinico-electrocardiographic variants of combined lesions of the sinoatrial and atrioventricular nodes].

A study of 71 patients with atrioventricular blocks and 57 patients with the sick-sinus syndrome (SSS) revealed electrophysiologic evidence of sinus dysfunction in 38 (53.5%) patients with atrioventricular blocks. Sinus dysfunction was due to pathologic vegetative effects in 15 (21.1%) patients with AV blocks, and a pathology of the sinus node itself in 23 (32.4%). Impaired atrioventricular conductivity, was registered in 29 (38.7%) patients with the SSS. A disorder of atrioventricular automatism was detected in 38 patients, and was combined with impaired AV conductivity in 19 of those. Five clinico-electrocardiographic variants of binodal heart disease have been identified, and possible therapies are discussed for each of those.

Adolescent↗

PubMed1994

Atrioventricular node re-entry of the common variety. Unusual location for the fast pathway.

Radiofrequency ablation was attempted in a 17-year-old man with atrioventricular node re-entry of the common variety. Energy was delivered to three sites around the ostium of the coronary sinus. The third attempt resulted in a sudden increase in AH interval with loss of retrograde conduction. The arrhythmia was no longer inducible. These observations may suggest the unusual location of the fast pathway.

Adolescent↗

PubMed1992

An anatomically guided approach to atrioventricular node slow pathway ablation.

Radiofrequency ablation of the "slow" pathway of the atrioventricular (AV) node reentrant circuit may be guided by electrophysiologic ("slow pathway potential") or anatomic landmarks. Experience with a systematic, anatomically guided approach in 25 patients (20 women and 5 men, aged 38 +/- 15 years) with typical AV node reentry is described. The slow pathway is assumed to be the posterior input to the AV node, approaching the nodal region in the corridor between the tricuspid annulus and the orifice of the coronary sinus. A series of radiofrequency lesions are given to interrupt this corridor at its entrance to Koch's triangle. If this is unsuccessful, the series of lesions are repeated progressively at higher levels approaching the AV node. The major end point for success is elimination of the slow pathway as determined by extrastimulus testing. A mean of 1.2 +/- 0.2 ablative sessions (20 +/- 12 applications of energy) achieved clinical success in 24 of 25 patients (96%) at a follow-up of 8.6 +/- 2.2 months. Anterograde Wenckebach cycle length increased from 361 +/- 67 ms to 398 +/- 70 ms (p = 0.01), yet the atrio-Hisian interval in sinus rhythm did not change (69 +/- 17 ms before vs 65 +/- 15 ms after ablation), p = 0.22. Retrograde Wenckebach cycle length was not affected (348 +/- 78 ms before vs 366 +/- 82 ms after ablation). During ablation, transient third-degree AV block occurred in 6 patients with no permanent sequelae. This approach provides a systematic, expedient technique to eliminate slow pathway conduction based on anatomic landmarks.

Adult↗

PubMed1987

Cryosurgical modification of the atrioventricular node: a closed heart approach in the dog.

Intraoperative modification of the atrioventricular (AV) node to prolong refractoriness could be an alternative to His bundle ablation in patients with refractory supraventricular arrhythmias. It was postulated that a cryosurgical lesion at the posterior interatrial septum in the closed heart could achieve this. An electrophysiologic study was performed in anesthetized dogs. The AV fat pad was mobilized to expose the posteroseptal region. A cryoprobe cooled to 0 to -10 degrees C was moved in the exposed region until reversible AV block indicated proximity of the AV node. The probe was then cooled to -70 degrees C for 30 seconds. Four weeks later, five dogs had a favorable result with a mean prolongation of Wenckebach cycle length of 45 +/- 7% (p less than 0.05). Two dogs had complete heart block. Decreased (one dog) or increased (one dog) duration of freezing resulted in no change and complete heart block, respectively. Histologic examination verified partial damage to the AV node with preservation of the His bundle. Thus, controlled cryoinjury to modify AV node function is feasible in the closed heart; preservation of AV conduction provides an advantage over His bundle ablation.

Animals↗

PubMed1977

The relationship between innervation and the cholinesterases of the rat atrioventricular node.

During the first 4 postnatal days, the atrioventricular specialized tissue of the rat contains butyrylcholinesterase alone. The next 7 days are associated with a mixture of both acetyl and butyryl activity, but after the 12th day, acetylcholinesterase is found to predominate largely. It is suggested that this change in activity is related to the growth of adrenergic nerves into the heart on the 4th day. Administration of antinerve growth factor prevents the development of these nerves and is found to delay the onset of the change in cholinesterase activity from butyryl to acetyl from the 5th day until the 21st. Only after the 31st day is acetylcholinesterase the most prominent enzyme in treated animals.

Acetylcholinesterase↗

PubMed1986

Canine atrioventricular node: scanning electron microscopy and enzyme histochemistry.

Morphologic features of the canine atrioventricular (AV) node were evaluated, using histochemical cholinesterase reactions and scanning electron microscopy. Three distinct regions of the AV node were observed: the transitional zone, superficial AV node, and deep AV node. The transitional zone lacked distinct cellular arrangement, and the cells were large and round with extensive branching on the ends. Superficial AV nodal cells were elongated, tightly packed, and smaller than were transitional cells. The superficial AV node was the densest zone of the AV node. Cell-to-cell contact was end-to-end. Deep AV nodal cells were long, formed laminated fascicles, were larger than the superficial AV nodal cells, and were continuous with the AV bundle.

Acetylcholinesterase↗

PubMed1998

[Hemodynamic deterioration in patients submitted to ablation of the atrioventricular node].

INTRODUCTION: Radiofrequency ablation of the atrioventricular conduction system has become an established therapy for patients with drug-refractory atrial fibrillation. We observed 14 patients with hemodynamic deterioration related to worsening of mitral regurgitation after the procedure. PATIENTS AND METHODS: We retrospectively evaluated 256 consecutive patients with drug-refractory atrial fibrillation referred for radiofrequency ablation of the AV node and implantation of a pacemaker. Because we found hemodynamic deterioration related to worsening mitral regurgitation, we compared the clinical history, electrophysiologic and echocardiographic data from the patients with hemodynamic deterioration and worsening mitral regurgitation (group A) with those without hemodynamic deterioration (group B). RESULTS: Fourteen out of 256 patients (group A) undergoing ablation of the atrioventricular conduction system deteriorated with acute pulmonary edema (3 patients) or congestive heart failure (11 patients) at a mean of 6 weeks after the ablation procedure. Four of these patients were referred for mitral valve surgery. The length of the procedure and the number of applications during ablation were similar in both groups. Compared with group B patients, group A patients had significantly higher left ventricular end-diastolic diameters (64 +/- 6 mm vs 56 +/- 9 mm; p < 0.05) at baseline despite similar left ventricular end-systolic diameters, fractional shortening and grade of mitral regurgitation (1.15 +/- 1.05 vs 1.11 +/- 0.97). Moreover, whereas no change was observed in left ventricular end-diastolic diameter, left ventricular end-systolic diameter, fractional shortening and grade of mitral regurgitation in group B patients after ablation, group A patients experienced a significant increase in left ventricular end-diastolic diameter (64 +/- 6 mm vs 72 +/- 9 mm; p < 0.01) and grade of mitral regurgitation (1.15 +/- 1.05 vs 2.90 +/- 1.15; p < 0.01). In patients operated on no ablation related structural damage to the mitral valve apparatus could be detected. The worsening of the mitral regurgitation was related to dilation of the mitral valve annulus. CONCLUSIONS: Hemodynamic deterioration together with progression of mitral regurgitation is a potential complication of ablation of the atrioventricular conduction system.

Adult↗

PubMed1993

Electrophysiological behavior of atrioventricular node after selective fast or slow pathway ablation in patients with atrioventricular nodal reentrant tachycardia.

One hundred twenty consecutive patients with symptomatic atrioventricular nodal reentrant tachycardia (AVNRT) underwent catheter ablation using radiofrequency energy. Fast pathway ablation was attempted in the first 16 consecutive patients by application of radiofrequency current in the anterior and superior aspect of the tricuspid annulus. Successful results were accomplished in 13 patients, complete atrioventricular (AV) block occurred in three. One hundred four patients underwent ablation of the slow pathway in the posterior and inferior aspect of the tricuspid annulus, which was successful in 98 patients. The remaining six patients subsequently underwent a fast pathway ablation with successful results in four and AV block in two. Therefore, 102 (98%) of the last 104 patients became free of AVNRT while maintaining intact AV conduction. This study characterizes the electrophysiological properties of the residual AV node following a selective fast or slow pathway ablation.

Atrioventricular Node↗