PubMed Health⌕ Search

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 253 records · Page 14Linked to original sources
PubMed1985

Right atrial thrombus formation after transvenous catheter ablation of the atrioventricular node.

The formation of a right atrial mass was detected in a patient by two-dimensional echocardiography 3 weeks after successful transvenous electrical ablation of the atrioventricular node had been performed. The mass was attached to the atrial septum at the site where the electrode catheter used for the ablation had supposedly been located and it exhibited no mobility. It was interpreted as a right atrial thrombus induced by the ablation procedure. Although no pulmonary embolic events have been observed during a 7 month follow-up period, right atrial thromboembolism must be considered a potentially dangerous complication of transvenous catheter ablation to control cardiac arrhythmias.

Adult↗
PubMed1993

Elimination of slow pathway conduction: an accurate indicator of clinical success after radiofrequency atrioventricular node modification.

OBJECTIVES: The purpose of this study was to determine the optimal end point of radiofrequency atrioventricular (AV) node modification using anatomically guided slow pathway approaches in patients with AV node reentrant tachycardia. BACKGROUND: The optimal end point for AV node modification using radiofrequency energy is uncertain, although elimination of inducible AV node reentrant tachycardia has been used. METHODS: We followed up 51 consecutive patients (40 women, 11 men, mean age +/- SD 41 +/- 16 years) with symptomatic AV node reentrant tachycardia for 12 +/- 6 months (range 4 to 24) after radiofrequency AV node modification using an anatomically guided slow pathway approach. Inducible AV node reentrant tachycardia was eliminated in all patients, whereas residual slow pathway conduction persisted in 12 patients (24%) after ablation. One study was complicated by complete AV block and two patients were lost to follow-up (one with and one without residual slow pathway conduction). RESULTS: Clinical recurrence of AV node reentrant tachycardia was documented in seven patients (14%) 3 days to 3 months (median 1 month) after ablation. The recurrence rate was significantly higher in patients with than in those without residual slow pathway conduction (6 [55%] of 11 vs. 1 [3%] of 37, p < 0.01). The recurrence rate was not different between patients with only residual slow pathway conduction and those with residual slow pathway conduction and inducible single echo cycles (three [60%] of five in both groups, p = NS). The number of radiofrequency energy applications was not significantly different between those without and those with recurrence (20 +/- 17 vs. 16 +/- 9, p = NS). Junctional tachycardia during application of radiofrequency energy tended to be more frequently observed in those with a successful outcome (77% vs. 57%, p > 0.05). Of the 22 patients who underwent modification before 1992, residual slow pathway conduction was present in 9 (41%) of 22 patients. Atrioventricular node reentrant tachycardia recurred in five (56%) of these nine patients. A greater effort made in 1992 to eliminate slow pathway conduction in 29 patients resulted in residual slow pathway conduction in only 3 (11%) with recurrence in 2 (4%). CONCLUSIONS: Complete elimination of slow pathway conduction is feasible in the majority of patients. Elimination of slow pathway conduction is highly predictive of long-term success after AV node modification using an anatomically guided approach.

Adult↗
PubMed2005

Permanent His-bundle pacing after atrioventricular node ablation in a patient with chronic atrial fibrillation and mitral regurgitation.

Hemodynamic deterioration because of worsening of mitral regurgitation can occur in a small number of patients undergoing atrioventricular node (AVN) ablation and pacing therapy. Patients with moderate mitral regurgitation before ablation seem prone to this complication. Successful permanent His-bundle pacing after AVN ablation was performed in a patient with chronic atrial fibrillation and moderate mitral regurgitation. Pulmonary capillary wedge pressure V-wave amplitude was markedly diminished and the mitral regurgitation area, calculated from the echocardiogram, was decreased by His-bundle pacing compared with that during right ventricular outflow tract or apical pacing.

Aged↗
PubMed1994

[Short-term pharmacological block of the atrioventricular node in the diagnosis of cardiac arrhythmias].

73 patients were examined with the aim of establishing the clinical importance of the method of short-term pharmacologic blockage (SPB) of atrioventricular node (AVN) in the diagnosis of paroxysmal tachycardias, latent forms of ventricular pre-excitation and attached forms of parasystole. SPB AVN was performed as an intravenous bolus of adenosinetriphosphate (ATP) in graded doses (10-30 mg) with simultaneous ECG recording. If adverse effects of ATP occurred its reinfusions were tapered to a dose of 5-10-15 mg in the presence of preliminary intravenously administered verapamil (5 mg). Objective nature of the diagnostic information obtained by using SPB AVN in the above outlined cardiac arrhythmias is analysed.

Adenosine Triphosphate↗
PubMed1981

Function of atrioventricular node conduction: hyperbolic model.

Twenty four patients were subjected to an electrophysiologic clinical procedure. The conventional extrastimulus test was applied to verify the relation between conduction time increase through the atrioventricular node of the extrastimulus beat (delta AH), and its preceding interval (A1A2). Following the least square root method the parameters of the hyperbolic model delta AH.A1A2 = m . delta AH + n were adjusted. The correlation coefficients obtained and tested in all cases were very high and significant. From this hyperbolic equation it was possible to determine the equations for the effective refractory period (ERPe = m) and functional refractory period (FRPe = ERPe + n). The theoretical values for refractoriness approached very closely those of the actually measured ERP and FRP, in all cases. This model proved to be, in respect to adjustments and especially in calculating refractory periods, at least as good as the exponential model proposed previously by other authors.

Adolescent↗
PubMed2001

Radiofrequency ablation at the coronary sinus ostium interrupts the vagal efferent input to the atrioventricular node in the canine heart.

The fat pad at the junction of the inferior vena cava and inferior left atrium is the area of convergence of vagal projections into the atrioventricular node (AVN) region. The present study investigated whether radiofrequency (RF) ablation applied to the area around the coronary sinus (CS) ostium would impair vagal input to the AVN in the canine heart. Twenty-four dogs were anesthetized by sodium pentobarbital and RF energy was delivered at 20W for 5-10s. In the baseline state without vagal stimulation (10Hz, 2ms), the electrophysiological variables did not change significantly after RF ablation. Vagally induced changes in the sinus cycle length and effective refractory period of the right atrium and left ventricle did not differ after RF ablation. However, the effects of vagal stimulation on the AVN function were impaired after RF ablation to the CS area from the ostium to 10mm within the ostium. After ablation was applied to the fast pathway area, the vagally induced changes in the AVN function decreased, but these changes were not affected after RF ablation in the slow pathway area. RF ablation in the vicinity of the CS would attenuate vagal input to the AVN.

Animals↗
PubMed1990

Fatal Lyme carditis and endodermal heterotopia of the atrioventricular node.

A fatal case of Lyme carditis occurring in a Suffolk farmworker is reported. Post-mortem examination of the heart showed pericarditis, focal myocarditis and prominent endocardial and interstitial fibrosis. The additional finding of endodermal heterotopia ('mesothelioma') of the atrioventricular node raises the possibility that this could also be related to Lyme infection and account for the relatively frequent occurrence of atrioventricular block in this condition. Lyme disease should always be considered in a case of atrioventricular block, particularly in a young patient from a rural area. The heart block tends to improve and therefore only temporary pacing may be required.

Adult↗
PubMed1985

Filtering role of the atrioventricular node in atrial fibrillations.

Experiments on rabbit heart preparations were carried out with the aim of studying the causal relation between the signals at the input and at the output of the atrioventricular node (AVN) during atrial fibrillations (AF). Electrograms were recorded simultaneously from the posterior and anterior inputs and from the output of AVN, together with cellular action potentials from one or two structures of the node. AVN is shown to play the role of a filtering unit for the excitatory waves passing from the atria to the ventricles during AF. The random and fragmentary character of the atrial excitatory front during AF causes summation of excitatory waves, local and manifested re-entry, and conduction along competitive pathways. These processes accompany both the successful conduction through AVN and the blocking of the excitation at different levels in the node. The filtration process takes place mainly in the AN- and N-zones of the node. In the NH-zone conduction does not differ compared to that in the case of spontaneous rhythm. The results obtained show that conduction through AVN during AF does not take place through triggering of specific mechanisms, but through a complex combination of the mechanisms characterizing the deteriorated conduction under extreme conditions.

Animals↗
PubMed1994

Intracellular calcium transients recorded with Fura-2 in spontaneously active myocytes isolated from the atrioventricular node of the rabbit heart.

We have used the fluorescent Ca indicator Fura-2 to assess the changes in intracellular calcium (Cai) in single spontaneously active myocytes isolated from the rabbit atrioventricular node (AVN). Simultaneous recordings of membrane potential and the Fura-2 ratio signal (which reflects Cai) showed that a transient rise of Cai occurred with each spontaneous action potential (AP). The AP upstroke preceded the rise in Cai and repolarization of the AP occurred faster than the decline of Cai. The level of Cai remained raised and progressively declined towards a baseline diastolic level during the subsequent pacemaker depolarization. The Fura-2 (Cai) transient in spontaneously active AVN cells had a time-to-peak of 49.2 +/- 5.4 ms (mean +/- s.e.m.; n = 7) and declined with a single exponential time course (time constant = 139.8 +/- 23.9 ms; n = 7). Application of 10 microM ryanodine completely and irreversibly abolished the Cai transient, identifying the sarcoplasmic reticulum (SR) as the major source of releasable Ca. Both removal of external Ca and block of L-type Ca channels (with 2 microM nifedipine) also abolished Cai transients, suggesting that Ca entry via L-type Ca-channels is involved in triggering the SR Ca release underlying the Cai transient. Removal of external Na (in the presence of 20 microM nifedipine to block L-type Ca channels) caused a reversible increase in Cai, showing that Na/Ca exchange is present in AVN cells and that it is involved in Cai regulation. Spontaneous Cai transients were abolished by 1 microM acetylcholine, and this was associated with a hyperpolarization of membrane potential and cessation of action potentials.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1987

[Influence of the autonomic nervous system on the normal and pathological atrioventricular node].

The finding of a first-degree atrioventricular block suggests various mechanisms of atrioventricular (AV) node alteration: organic lesion, or functional disorder related to the autonomic nervous system, or a combination of both. The influence of the autonomic nervous system was evaluated by administration of Jose's regimen, i.e. intravenous injection of propranolol 0.2 mg/kg bodyweight and atropine 0.04 mg/kg bodyweight. This regimen was tested in 101 patients divided into two groups: 38 subjects with normal sinus node and AV node acting as controls, and 63 patients with abnormal AV node. In the control group the autonomic nervous system had no influence on atrio-hisian (AH) conduction time or on the effective refractory period of the AV node under an imposed cycle of 600 ms. Wenckebach's period significantly (p less than 0.01) increased from 352 +/- 40 ms to 376 +/- 47 ms. Parasympathetic activity was found to predominate in the sinus node. In the group with pathological AV node three types of response were observed after pharmacological inhibition of the autonomic nervous system: (a) improvement or even complete normalization (40%) of AV node conduction ability (AH, Wenckebach's period) suggesting vagal hyperactivity, as also found in the sinus node; (b) changes similar to those observed in the control group and reflecting the same behaviour of the autonomic nervous system, and (c) increase in AH conduction abnormalities reflecting the presence of a sympathetic overdrive tending to minimize the consequences of an atrioventricular organic lesion. This sympathetic overdrive was also found to be present in the sinus node.

Adolescent↗
PubMed1987

A case of swallow syncope induced by vagotonic visceral reflex resulting in atrioventricular node suppression.

A 48-year-old man repeatedly experienced syncope associated with paroxysmal atrioventricular block (PAVB) while swallowing. PAVB ("Mobitz type II" AH block) occurred only when "balloon-like" deformity of the lower esophagus developed. Balloon inflation in the lower esophagus induced PAVB. However, inflation in the upper or mid portion, or other vagal maneuvers, caused only sinus slowing. PAVB was not induced after intravenous atropine. The PAVB in this patient was probably caused by a vagotonic reflex triggered by tensoreceptors in the lower esophagus, resulting in selective suppression of the atrioventricular node.

Deglutition↗
PubMedDate not supplied

Endodermal heterotopia of the atrioventricular node associated with transposition of the great arteries.

A 13-year-old girl with surgically corrected complete transposition of the great arteries died suddenly while walking to school. Postmortem examination revealed endodermal heterotopia of the atrioventricular node, a condition not previously associated with transposition of the great arteries. New immunohistochemical observations are described, and the embryogenesis of the condition and its association with complete transposition are discussed.

Adolescent↗
PubMedDate not supplied

[Individual and age-related variability of the arteries to the atrioventricular node in the human heart].

Investigation was performed on 501 preparations of the hearts of people of various age without the pathology of cardiovascular system. Complex of morphological methods, including morphometry was used in the work. Individual variability of the atrioventricular node artery was established to be characterized by diverse diameter and length (within limits, determined for every age), direction, branching characteristics, zones of distribution, and different participation in blood supply of the atrioventricular region of conducting system of the heart.

Adult↗
PubMed1992

A degenerative lesion of the approach to the atrioventricular node producing second-degree and third-degree atrioventricular block.

We report a case of a degenerative approach lesion in an 83-year-old male with diabetes mellitus, hypertension, and ischemic heart disease. His ECGs changed from first-degree atrioventricular (AV) block 14 years ago, to third-degree AV (A-H) block. A pacemaker was implanted for bradycardia. He died 4 years later from heart and renal failure. Serial sections through the conduction system revealed total depletion and fatty replacement of the atrial muscle at the approaches to the AV node.

Aged↗