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Cardiology Journal 2009Cardiac resynchronization therapy (CRT) is an important advance for the treatment of end-stage heart failure (HF). About 15-50% of HF is complicated by atrial... (Review)
Review
Cardiac resynchronization therapy (CRT) is an important advance for the treatment of end-stage heart failure (HF). About 15-50% of HF is complicated by atrial fibrillation (AF), associated with worsened outcomes. The presence of AF may interfere with optimal delivery of CRT due to competition with biventricular (BiV) capture by conducted beats. Pacing algorithms in newer devices may not ensure consistent CRT delivery during periods of rapid ventricular rates. Atrioventricular junction ablation with permanent pacing eliminates interference by conducted beats and provides complete BiV capture and is associated with improved outcomes. Catheter ablation of AF is another promising alternative to maintain sinus rhythm in patients with AF and HF. However, the optimal indications for CRT delivery for patients in this complex cohort remain to be assessed in randomized clinical trials.
Topics: Algorithms; Atrial Fibrillation; Atrioventricular Node; Cardiac Pacing, Artificial; Catheter Ablation; Clinical Trials as Topic; Combined Modality Therapy; Heart Failure; Heart Rate; Humans; Pacemaker, Artificial; Treatment Outcome
PubMed: 19130410
DOI: No ID Found -
Journal of the American College of... Feb 1993We compared the electrophysiologic effects on atrioventricular (AV) node physiology of selective "fast" versus selective "slow" pathway radiofrequency ablation in 42... (Comparative Study)
Comparative Study
OBJECTIVES
We compared the electrophysiologic effects on atrioventricular (AV) node physiology of selective "fast" versus selective "slow" pathway radiofrequency ablation in 42 patients with drug-resistant AV node reentrant tachycardia who underwent 51 ablation attempts to prevent tachycardia recurrence while preserving AV conduction.
BACKGROUND
The recent introduction of radiofrequency ablation to treat AV node reentrant tachycardia allows the opportunity to study the effects of selective elimination of the different limbs involved in AV node reentrant tachycardia.
METHODS
Selective fast pathway ablation was attempted in 13 patients by delivering radiofrequency energy anteriorly across the tricuspid valve anulus. Selective slow pathway ablation was attempted in 29 patients by delivering radiofrequency energy posteriorly across the tricuspid valve anulus at sites where putative slow pathway potentials were recorded.
RESULTS
Selective fast pathway ablation eliminated AV node reentrant tachycardia without AV block in 6 (46%) of 13 patients after one ablation session and in an additional 3 patients (69% of total) after repeat ablation sessions. Slow pathway ablation eliminated AV node reentrant tachycardia without AV block in 26 (90%) of 29 patients after one radiofrequency ablation session and in an additional 2 patients (97% of total) after repeat ablation sessions. Selective fast pathway ablation increased the PR interval (140 to 220 ms, p = 0.0001) and AH interval (66 to 153 ms, p = 0.0001), whereas slow pathway ablation did not change these intervals. Fast pathway radiofrequency ablation caused retrograde block in 7 (64%) of 11 patients, whereas no patients undergoing slow pathway ablation developed selective retrograde block. Single AV node echo beats were commonly induced after slow but not fast pathway ablation (17 of 29 patients vs. 1 of 11 patients, respectively, p = 0.01) and did not predict recurrence of AV node reentrant tachycardia.
CONCLUSIONS
Successful selective radiofrequency ablation of fast or slow pathways in patients with AV node reentrant tachycardia resulted in different electrophysiologic properties after ablation. Slow pathway ablation produced more successful outcomes, with a decreased prevalence of recurrent AV node reentrant tachycardia or AV block.
Topics: Atrioventricular Node; Cardiac Pacing, Artificial; Catheter Ablation; Female; Follow-Up Studies; Humans; Male; Middle Aged; Recurrence; Tachycardia, Atrioventricular Nodal Reentry
PubMed: 8426009
DOI: 10.1016/0735-1097(93)90686-u -
British Heart Journal Jan 1981We have analysed the ventricular response as seen on the surface electrocardiogram in patients with paroxysmal atrial fibrillation and flutter in relation to the...
We have analysed the ventricular response as seen on the surface electrocardiogram in patients with paroxysmal atrial fibrillation and flutter in relation to the electrophysiological properties of the corresponding atrioventricular pathways. In 15 patients who had atrial fibrillation with conduction solely through the atrioventricular node, there was a significant correlation between th shortest and mean RR intervals during atrial fibrillation and the functional refractory period, "pre-Wenckebach cycle length", and the shortest ventricular cycle length that resulted from 1:1 atrioventricular conduction. In 18 patients with conduction through an accessory atrioventricular pathway the only good correlation was between the shortest and mean ventricular rate during atrial fibrillation and the "pre-Wenckebach cycle length" and shortest ventricular cycle length during 1:1 atrioventricular conduction. In 12 patients with an atriofascicular bypass tract or rapidly conducting atrioventricular node there was no significant correlation between the RR intervals during atrial fibrillation and the electrophysiological indices; the same lack of correlation was evident in all 11 patients with atrial flutter, all of whom had atrioventricular nodal conduction. The response of atrioventricular pathways to electrophysiological testing, particularly the use of incremental atrial pacing, provides useful guidance in the further management of these atrial arrhythmias.
Topics: Adult; Aged; Atrial Fibrillation; Atrial Flutter; Atrioventricular Node; Cardiac Pacing, Artificial; Electrocardiography; Female; Heart Conduction System; Heart Ventricles; Humans; Male; Middle Aged
PubMed: 7459168
DOI: 10.1136/hrt.45.1.83 -
Minerva Cardioangiologica Feb 2003Although we soon will be marking the 100th anniversary of the discovery of the atrioventricular (AV) node, the mysteries of this most complex of all parts of the... (Review)
Review
Although we soon will be marking the 100th anniversary of the discovery of the atrioventricular (AV) node, the mysteries of this most complex of all parts of the conduction system of the heart remain. We are still battling controversies related to the precise morphology of the AV node and its atrial approaches. We are still debating the exact reentrant pathways of the AV nodal reentrant tachycardia. We are still uncertain if the so-called dual AV nodal electrophysiology encompasses two or more pathways, and what exactly makes these pathways in the absence of distinct insulated cables between the atrium and the AV node. It may be just surprising, in view of the above limitations, that current level of knowledge has nevertheless made possible some of the most spectacular successes in the modern cardiac electrophysiology. Thus, the cases of typical AVNRT are cured with a very high rate of success by radiofrequency ablations, increasing the quality of life of thousands of patients. AV nodal modifications are being performed to slow the ventricular rate during atrial fibrillation, although more progress is needed in this endeavor. The goal of the present review is to outline the major anatomic and electrophysiologic efforts in understanding the mechanisms underlying the dual pathway AV nodal propagation and to trace some novel approaches that promise to widen the horizon of the experimental and clinical fields.
Topics: Animals; Atrial Fibrillation; Atrioventricular Node; Electrocardiography; Electrophysiology; Heart Conduction System; Humans
PubMed: 12652255
DOI: No ID Found -
Journal of Cardiovascular... Mar 2021The feasibility and outcomes of concomitant atrioventricular node ablation (AVNA) and leadless pacemaker implant are not well studied. We report outcomes in patients...
BACKGROUND
The feasibility and outcomes of concomitant atrioventricular node ablation (AVNA) and leadless pacemaker implant are not well studied. We report outcomes in patients undergoing Micra implant with concomitant AVNA.
METHODS
Patients undergoing AVNA at the time of Micra implant from the Micra Transcatheter Pacing (IDE) Study, Continued Access (CA) study, and Post-Approval Registry (PAR) were included in the analysis and compared to Micra patients without AVNA. Baseline characteristics, acute and follow-up outcomes, and electrical performance were compared between patients with and without AVNA during the follow-up period.
RESULTS
A total of 192 patients (mean age 77.4 ± 8.9 years, 72% female) underwent AVNA at the time of Micra implant and were followed for 20.4 ± 15.6 months. AVNA patients were older, more frequently female, and tended to have more co-morbid conditions compared with non-AVNA patients (N = 2616). Implant was successful in 191 of 192 patients (99.5%). The mean pacing threshold at implant was 0.58 ± 0.35 V and remained stable during follow-up. Major complications within 30 days occurred more frequently in AVNA patients than non-AVNA patients (7.3% vs. 2.0%, p < .001). The risk of major complications through 36-months was higher in AVNA patients (hazard ratio: 3.81, 95% confidence interval: 2.33-6.23, p < .001). Intermittent loss of capture occurred in three AVNA patients (1.6%), all were within 30 days of implant and required system revision. There were no device macrodislodgements or unexpected device malfunctions.
CONCLUSION
Concomitant AVN ablation and leadless pacemaker implant is feasible. Pacing thresholds are stable over time. However, patient comorbidities and the risk of major complications are higher in patients undergoing AVNA.
Topics: Aged; Aged, 80 and over; Atrioventricular Node; Female; Humans; Male; Pacemaker, Artificial; Registries; Treatment Outcome
PubMed: 33428248
DOI: 10.1111/jce.14881 -
Journal of the American Heart... Jun 2016Radiofrequency ablation (RFA) for atrioventricular nodal reentrant tachycardia appears to reduce atrial tachycardia, which might relate to parasympathetic denervation at...
BACKGROUND
Radiofrequency ablation (RFA) for atrioventricular nodal reentrant tachycardia appears to reduce atrial tachycardia, which might relate to parasympathetic denervation at cardiac ganglionated plexuses.
METHODS AND RESULTS
Compared to 7 control canines without RFA, in 14 canines, RFA at the bottom of Koch's triangle attenuated vagal stimulation-induced effective refractory periods prolongation in atrioventricular nodal and discontinuous atrioventricular conduction curves but had no effect on the sinoatrial node. RFA attenuated vagal stimulation-induced atrial effective refractory periods shortening and vulnerability window of atrial fibrillation widening in the inferior right atrium and proximal coronary sinus but not in the high right atrium and distal coronary sinus. Moreover, RFA anatomically impaired the epicardial ganglionated plexuses at the inferior vena cava‒inferior left atrial junction. This method was also investigated in 42 patients who had undergone ablation of atrioventricular nodal reentrant tachycardia, or 12 with an accessory pathway (AP) at the posterior septum (AP-PS), and 34 patients who had an AP at the free wall as control. In patients with atrioventricular nodal reentrant tachycardia and AP-PS, RFA at the bottom of Koch's triangle prolonged atrial effective refractory periods and reduced vulnerability windows of atrial fibrillation widening at the inferior right atrium, distal coronary sinus and proximal coronary sinus but not the high right atrium. In patients with AP-free wall, RFA had no significant atrial effects.
CONCLUSIONS
RFA at the bottom of Koch's triangle attenuated local autonomic innervation in the atrioventricular node and atria, decreased vagal stimulation-induced discontinuous atrioventricular nodal conduction, and reduced atrial fibrillation inducibility due to impaired ganglionated plexuses. In patients with atrioventricular nodal reentrant tachycardia or AP-PS, RFA prolonged atrial effective refractory periods, and narrowed vulnerability windows of atrial fibrillation.
Topics: Analysis of Variance; Animals; Atrioventricular Node; Cardiac Pacing, Artificial; Catheter Ablation; Dogs; Female; Heart Rate; Humans; Male; Middle Aged; Neural Conduction; Parasympathectomy; Sinoatrial Node; Tachycardia, Atrioventricular Nodal Reentry; Vagus Nerve Stimulation
PubMed: 27287698
DOI: 10.1161/JAHA.115.003083 -
Journal of the American College of... Oct 1992A comprehensive electrophysiologic study followed by selective radiofrequency ablation from three sites was performed in patients with atrioventricular (AV) node...
OBJECTIVES
A comprehensive electrophysiologic study followed by selective radiofrequency ablation from three sites was performed in patients with atrioventricular (AV) node reentrant tachycardia to better delineate the nature of the tachycardia circuit.
BACKGROUND
We postulated that the retrograde fast pathway is the anterior superficial group of transitional cells and the slow pathway is the compact node with its posterior input of transitional cells. Twenty-three consecutive patients were studied. In nine, the atria could be dissociated from the tachycardia by delivery of an atrial extrastimulus during tachycardia.
METHODS
Radiofrequency ablation was performed with three approaches. The anterior approach was designed to interrupt the anterior superficial atrial input to the compact node, the posterior approach to interrupt the posterior atrial input to the compact node and the inferior approach to destroy the compact node itself.
RESULTS
Selective ablation of the retrograde fast pathway was achieved in seven patients, six with the anterior and one with the inferior approach. Anterograde fast pathway conduction was not affected, whereas retrograde fast pathway conduction was either abolished or markedly depressed. None had induction of echoes or tachycardia after ablation. Selective ablation of the slow pathway was successful in 13 patients, 1 with anterior, 3 with posterior and 9 with inferior approaches. In these 13 patients, both anterograde and retrograde fast pathway conduction were not affected, the dual pathway physiology was abolished and the tachycardia was not inducible after ablation. Ablation of both the retrograde fast pathway and the slow pathway occurred with the inferior approach in three patients.
CONCLUSIONS
We conclude that the retrograde fast pathway is likely to be the anterior superficial group of transitional cells, whereas the slow pathway is the compact node and its posterior input of transitional cells. A barrier seems to exist between the atrium and the tachycardia circuit. In a broad view of the AV node structure, the tachycardia circuit is confined to the node.
Topics: Atrial Function; Atrioventricular Node; Cardiac Catheterization; Cardiac Pacing, Artificial; Electrocardiography; Electrocoagulation; Female; Humans; Intraoperative Care; Male; Middle Aged; Radio Waves; Tachycardia, Atrioventricular Nodal Reentry
PubMed: 1527299
DOI: 10.1016/0735-1097(92)90189-t -
Circulation Jun 2001The remarkable success of radiofrequency ablation in recent decades in curing atrioventricular nodal reentrant tachycardias has intensified efforts to provide a solid... (Review)
Review
The remarkable success of radiofrequency ablation in recent decades in curing atrioventricular nodal reentrant tachycardias has intensified efforts to provide a solid theoretical basis for understanding the mechanisms of atrioventricular transmission. These efforts, which were made by both anatomists and electrophysiologists, frequently resulted in seemingly controversial observations. Quantitatively and qualitatively, our understanding of the mysteries of propagation through the inhomogeneous and extremely complex atrioventricular conduction axis is much deeper than it was at the beginning of the past century. We must go back to the initial sources, nonetheless, in an attempt to provide a common ground for evaluating the morphological and electrophysiological principles of junctional arrhythmias. In this review, we provide an account of the initial descriptions, which still provide an appropriate foundation for interpreting recent electrophysiological findings.
Topics: Atrioventricular Node; Electrophysiology; Heart; Heart Conduction System; Humans
PubMed: 11390334
DOI: 10.1161/01.cir.103.22.2660 -
Circulation Research May 2012The cardiac conduction system is a specialized tract of myocardial cells responsible for maintaining normal cardiac rhythm. Given its critical role in coordinating... (Review)
Review
The cardiac conduction system is a specialized tract of myocardial cells responsible for maintaining normal cardiac rhythm. Given its critical role in coordinating cardiac performance, a detailed analysis of the molecular mechanisms underlying conduction system formation should inform our understanding of arrhythmia pathophysiology and affect the development of novel therapeutic strategies. Historically, the ability to distinguish cells of the conduction system from neighboring working myocytes presented a major technical challenge for performing comprehensive mechanistic studies. Early lineage tracing experiments suggested that conduction cells derive from cardiomyocyte precursors, and these claims have been substantiated by using more contemporary approaches. However, regional specialization of conduction cells adds an additional layer of complexity to this system, and it appears that different components of the conduction system utilize unique modes of developmental formation. The identification of numerous transcription factors and their downstream target genes involved in regional differentiation of the conduction system has provided insight into how lineage commitment is achieved. Furthermore, by adopting cutting-edge genetic techniques in combination with sophisticated phenotyping capabilities, investigators have made substantial progress in delineating the regulatory networks that orchestrate conduction system formation and their role in cardiac rhythm and physiology. This review describes the connectivity of these gene regulatory networks in cardiac conduction system development and discusses how they provide a foundation for understanding normal and pathological human cardiac rhythms.
Topics: Animals; Atrioventricular Node; Gene Expression Regulation, Developmental; Gene Regulatory Networks; Genotype; Heart Conduction System; Heart Diseases; Humans; Phenotype; Purkinje Fibers; Sinoatrial Node; Transcription Factors
PubMed: 22628576
DOI: 10.1161/CIRCRESAHA.111.260026 -
Clinical Cardiology Mar 2018
Topics: Atrioventricular Block; Atrioventricular Node; Electrocardiography; Heart Rate; Humans
PubMed: 29460961
DOI: 10.1002/clc.22874