atrioventricular node
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Author(s):  
Jogendra Singh ◽  
Dibyasundar Mahanta ◽  
Rudra Pratap Mahapatra ◽  
Debasis Acharya ◽  
Ramachandra Barik

A 57-year-old male presented with recurrent palpitations. He was diagnosed with rheumatic mitral stenosis, right posterior septal accessory pathway and atrial flutter. An electrophysiological study after percutaneous balloon mitral valvotomy showed that the palpitations were due to atrial flutter with right bundle branch aberrancy. The right posterior septal pathway was a bystander because it had higher refractory period than atrioventricular node.


Heart ◽  
2021 ◽  
pp. heartjnl-2021-320304
Author(s):  
Damián Sánchez-Quintana ◽  
Robert H Anderson ◽  
Justin T Tretter ◽  
José Angel Cabrera ◽  
Eduardo Back Sternick ◽  
...  

Knowledge of the anatomy of the ‘conduction tissues’ of the heart is a 20th century phenomenon. Although controversies still continue on the topic, most could have been avoided had greater attention been paid to the original descriptions. All cardiomyocytes, of course, have the capacity to conduct the cardiac impulse. The tissues specifically described as ‘conducting’ first generate the cardiac impulse, and then deliver it in such a fashion that the ventricles contract in orderly fashion. The tissues cannot readily be distinguished by gross inspection. Robust definitions for their recognition had been provided by the end of the first decade of the 20th century. These definitions retain their currency. The sinus node lies as a cigar-shaped structure subepicardially within the terminal groove. There is evidence that it is associated with a paranodal area that may have functional significance. Suggestions of dual nodes, however, are without histological confirmation. The atrioventricular node is located within the triangle of Koch, with significant inferior extensions occupying the atrial vestibules and with septal connections. The conduction axis penetrates the insulating plane of the atrioventricular junctions to continue as the ventricular pathways. Remnants of a ring of cardiomyocytes observed during development are also to be found within the atrial vestibules, particularly a prominent retroaortic remnant, although that their role has still to be determined. Application of the initial criteria for nodes and tracts shows that there are no special ‘conducting tissues’ in the pulmonary venous sleeves that might underscore the abnormal rhythm of atrial fibrillation.


2021 ◽  
Vol 10 (4) ◽  
pp. 262-272
Author(s):  
Robert H Anderson ◽  
Jill PJM Hikspoors ◽  
Justin T Tretter ◽  
Yolanda Mac�as ◽  
Diane E Spicer ◽  
...  

The pathways for excitation of the atrioventricular node enter either superiorly, as the so-called ‘fast’ pathway, or inferiorly as the ‘slow’ pathway. However, knowledge of the specific anatomical details of these pathways is limited. Most of the experimental studies that established the existence of these pathways were conducted in mammalian hearts, which have subtle differences to human hearts. In this review, the authors summarise their recent experiences investigating human cardiac development, correlating these results with the arrangement of the connections between the atrial myocardium and the compact atrioventricular node as revealed by serial sectioning of adult human hearts. They discuss the contributions made from the atrioventricular canal myocardium, as opposed to the primary ring. Both these rings are incorporated into the atrial vestibules, albeit with the primary ring contributing only to the tricuspid vestibule. The atrial septal cardiomyocytes are relatively late contributors to the nodal inputs. Finally, they relate our findings of human cardiac development to the postnatal arrangement.


Heart Rhythm ◽  
2021 ◽  
Author(s):  
Hiroshige Yamabe ◽  
Toshiya Soejima ◽  
Kimihiro Kajiyama ◽  
Yurie Fukami ◽  
Kazuki Haraguchi ◽  
...  

2021 ◽  
Vol 23 (Supplement_G) ◽  
Author(s):  
Gaetano Liccardo ◽  
Francesco Cannata ◽  
Mauro Chiarito ◽  
Sara Bombace ◽  
Marta Maccallini ◽  
...  

Abstract Aims Atrial fibrillation (AF) and heart failure (HF) are increasing in prevalence worldwide and, when present altogether, are associated with significant mortality and morbidity. Several and recent randomized clinical trials have reported an improvement of clinical outcomes in patients with HF and AF with catheter ablation. To provide a comprehensive and updated synthesis of effect estimates of the available randomized and observational clinical trials comparing pulmonary vein isolation with optimal medical therapy (rate or rhythm) or atrioventricular node ablation and resynchronization. Methods and results MEDLINE database was searched from inception to 4 March 2021 by two reviewers (F.C. and M.C.) for relevant studies. The following key words were used: ‘atrial fibrillation’, ‘heart failure’, ‘ablation’, ‘medical’, ‘drug’, ‘rate’, ‘rhythm’, ‘resynchronization’, and ‘atrial flutter’. The co-primary outcomes were all-cause death and hospitalization for HF. A total of 16 studies enrolling 42 908 patients were included; of these, 9 were randomized controlled trials, 3 unadjusted observational studies, and 4 adjusted observational trials. Patients treated with catheter ablation had a statistically significant reduction for the risk of all-cause death {Figure on the left: odds ratio [OR]: 0.51, [95% confidence interval (CI): 0.31–0.84], P = 0.008, NNT 33} and hospitalization for HF [Figure on the right: OR: 0.52, (95% CI: 0.31–0.87), P 0.014, NNT 24]. Subgroup analysis confirmed these results only in HF with reduced ejection fraction subgroup. Meta-regression analyses showed a direct correlation between a higher burden of persistent/long-standing persistent AF and the positive impact of catheter ablation of AF. Moreover, the age of 70 years emerged as the cut-off age for a greater impact of catheter ablation. Conclusions Catheter ablation of AF is associated with a lower risk of all-cause death and HF hospitalizations in patients with AF and HF, as compared to medical therapy or atrioventricular node ablation and resynchronization. These results are mainly applicable for HF with reduced ejection fraction.


2021 ◽  
Vol 23 (Supplement_G) ◽  
Author(s):  
Antonio Gianluca Robles ◽  
Mattia Petrungaro ◽  
Maria Penco ◽  
Silvio Romano ◽  
Luigi Sciarra

Abstract Aims Ventricular pre-excitation is defined by the presence of all of the following electrocardiographic criteria: PQ interval duration ≤120 ms, QRS duration ≥120 ms, and presence of δ wave (defined as initial ‘slurring’ of the QRS complex). Ventricular pre-excitation together with the presence of symptoms (orthodromic and/or antidromic atrioventricular reentry tachycardia, atrial fibrillation) defines Wolff–Parkinson–White (WPW) syndrome. The anatomical substrate of ventricular pre-excitation consists of an extranodal accessory atrio-ventricular connection: the so-called Kent bundle. Such pathways can have antegrade, retrograde, or mixed conductive properties. Accessory pathways endowed with anterograde conductive capability may be responsible for manifest, intermittent, or non-manifest ventricular pre-excitation depending on whether it is respectively always visible on the ECG, not always visible on the ECG and not visible on the ECG even though the pathway has the ability to antegrade conduction. The rare phenomenon of supernormal conduction of anomalous pathways is part of the manifest pre-excitation, which represents the topic of the case reported below. Methods and results We report the clinical case of a young not agonist sportsman undergoing an electrophysiological study (SEF) because of he is suffering from ventricular pre-excitation. The SEF did not showed the inducibility of arrhythmias and, at the same time, apparently it showed low risk characteristics of the pathway even during adrenergic stimulus. However, a careful study, performed with atrial stimulation with couplings up to refractoriness of the atrioventricular node revealed supernormal conduction properties of the Kent bundle which proved to have high risk characteristics according to current guidelines and, therefore, was effectively treated with catheter ablation. Conclusions This case invites us to careful studying of accessory pathways properties, especially since, although rare, they may possess supernormal conduction characteristics capable of determining high ventricular rates in the case of sustained atrial tachyarrhythmias, especially in conditions of adrenergic hyperactivity.


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