Are there internodal tracts? Yes

Liebman, Jerome

doi:10.1016/0167-5273(85)90362-6

Cited by 20 publications

(5 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The medial and lateral atrionodal bundles represent the anatomical substrate for arrhythmias associated with dual AV nodal inputs (Wu, 1982;Liebman, 1985). Evidence for this hypothesis is that the alpha and beta AV nodal inputs (Zipes et al, 1973) are associated with the myocardium adjacent to the superior and inferior borders of the coronary sinus.…”

Section: Clinical Significancementioning

confidence: 99%

“…The current view is that ordinary contractile myocardium becomes continuous with the AVN from all levels as transitional fibers. However, electrophysiological findings, such as the attribution of certain clinical arrhythmias to AV nodal inputs with unique conductile properties (for reviews see Wu, 1982;and Liebman, 1985), suggest that functionally discrete bundles of specialized myocardium are continuous with the AVN.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Atrioventricular node and input pathways: A correlated gross anatomical and histological study of the canine atrioventricular junctional region

Racker¹

1989

Anat. Rec.

View full text Add to dashboard Cite

To determine the architecture of the atrioventricular (AV) junctional region, structures in atrial preparations were correlated to those in serial sections made either parallel or perpendicular to the long axis of the AV node (AVN)/AV bundle complex. The results demonstrated the following for the first time: 1) A right medial atrial wall (MAW) extends anteriorly from the interatrial septum, superior to the interventricular septum (IVS). 2) An atrial interventricular septum (A-IVS) groove is located between the base of the MAW and the crest of the IVS. 3) Three atrionodal bundles converge to form a proximal AV bundle (PAVB), which in turn is contiguous with the AVN. The atrionodal bundles are associated with the MAW or the superomedial and inferolateral margins of the coronory sinus. Terminal portions of the atrionodal bundles and the PAVB reside within the A-IVS groove. The AV bundle was termed distal (DAVB) to avoid confusion. 4) The location of the AVN/DAVB complex topographically is deep to the apex of the septal cusp of the tricuspid valve subjacent to the MAW. Intracardially, the AVN/DAVB complex is within the central fibrous body. Significantly, this study resulted in the first unequivocal demonstration of discrete bundles of myocardial fibers associated with the atrial end of the AV node. Moreover, it appears likely that the atrionodal AV bundles are continuous with the sinoatrial nodal extensions, thereby forming internodal tracts.

show abstract

Section: Clinical Significancementioning

confidence: 99%

mentioning

confidence: 99%

Atrioventricular node and input pathways: A correlated gross anatomical and histological study of the canine atrioventricular junctional region

Racker¹

1989

Anat. Rec.

View full text Add to dashboard Cite

show abstract

“…For instance, the myocardium at the left atrioventricular junction is not considered to be a part of the conduction system, although nodal action potentials and low abundance of gap junctions have been observed in the lower rim of the left atrium in the formed heart of various species (196). In addition, although internodal tracts are not considered to be significant components of the conduction system, their existence is an amazingly persistent, but highly controversial issue (16,56,138,182). One of the reasons for this persistency might again be confusion about terminology.…”

Section: Engrailed-2/lacz Transgene Expression: Speculations On Cardimentioning

confidence: 99%

Cardiac Chamber Formation: Development, Genes, and Evolution

Moorman

Christoffels

2003

Physiological Reviews

650

526

View full text Add to dashboard Cite

Moorman, Antoon F. M., and Vincent M. Christoffels. Cardiac Chamber Formation: Development, Genes, and Evolution. Physiol Rev 83: 1223-1267, 2003; 10.1152/physrev.00006.2003.—Concepts of cardiac development have greatly influenced the description of the formation of the four-chambered vertebrate heart. Traditionally, the embryonic tubular heart is considered to be a composite of serially arranged segments representing adult cardiac compartments. Conversion of such a serial arrangement into the parallel arrangement of the mammalian heart is difficult to understand. Logical integration of the development of the cardiac conduction system into the serial concept has remained puzzling as well. Therefore, the current description needed reconsideration, and we decided to evaluate the essentialities of cardiac design, its evolutionary and embryonic development, and the molecular pathways recruited to make the four-chambered mammalian heart. The three principal notions taken into consideration are as follows. 1) Both the ancestor chordate heart and the embryonic tubular heart of higher vertebrates consist of poorly developed and poorly coupled “pacemaker-like” cardiac muscle cells with the highest pacemaker activity at the venous pole, causing unidirectional peristaltic contraction waves. 2) From this heart tube, ventricular chambers differentiate ventrally and atrial chambers dorsally. The developing chambers display high proliferative activity and consist of structurally well-developed and well-coupled muscle cells with low pacemaker activity, which permits fast conduction of the impulse and efficacious contraction. The forming chambers remain flanked by slowly proliferating pacemaker-like myocardium that is temporally prevented from differentiating into chamber myocardium. 3) The trabecular myocardium proliferates slowly, consists of structurally poorly developed, but well-coupled, cells and contributes to the ventricular conduction system. The atrial and ventricular chambers of the formed heart are activated and interconnected by derivatives of embryonic myocardium. The topographical arrangement of the distinct cardiac muscle cells in the forming heart explains the embryonic electrocardiogram (ECG), does not require the invention of nodes, and allows a logical transition from a peristaltic tubular heart to a synchronously contracting four-chambered heart. This view on the development of cardiac design unfolds fascinating possibilities for future research.

show abstract

“…This domain is also characterized by the lack of expression of Cx40 and Cx43,18,33 and by the expression of Cx45 34–38. The internodal region has always been a highly contentious topic 39–41. Whether specialized (fast‐conducting) tracts would be present in between the nodes has been the subject of vehement discussions.…”

Section: Tbx2/3 Delineate the Areas That Give Rise To The Conduction mentioning

confidence: 99%

Development of the Building Plan of the Heart

Moorman

Soufan

Hagoort

et al. 2004

Annals of the New York Academy of Sciences

View full text Add to dashboard Cite

In this communication we discuss the formation of the synchronously contracting chambered heart from a peristaltically contracting linear heart tube. It is proposed that members of the T-box family of transcription factors play a crucial role in the formation of the building plan of the formed heart. Tbx5 may confer venoarterial polarity to the heart tube, whereas Tbx2 initially and Tbx3 in later developmental stages prevent the cardiac inflow tract, atrioventricular region, outflow tract, as well as the cardiac inner curvatures from chamber differentiation. With the exception of the outflow tract that becomes incorporated into the ventricles, these regions contribute to the cardiac conduction system.

show abstract

Are there internodal tracts? Yes

Cited by 20 publications

References 38 publications

Atrioventricular node and input pathways: A correlated gross anatomical and histological study of the canine atrioventricular junctional region

Atrioventricular node and input pathways: A correlated gross anatomical and histological study of the canine atrioventricular junctional region

Cardiac Chamber Formation: Development, Genes, and Evolution

Development of the Building Plan of the Heart

Contact Info

Product

Resources

About