A macroscopic anatomical investigation of atrioventricular bundle locational variation relative to the membranous part of the ventricular septum in elderly human hearts

2005 ◽  
Vol 27 (3) ◽  
pp. 206-213 ◽  
Author(s):  
Tomokazu Kawashima ◽  
Hiroshi Sasaki
Keyword(s):  
Ventricular Septum ◽  
Atrioventricular Bundle ◽  
Membranous Part

scholarly journals Specialized impulse conduction pathway in the alligator heart

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Bjarke Jensen ◽  
Bastiaan J Boukens ◽  
Dane A Crossley ◽  
Justin Conner ◽  
Rajiv A Mohan ◽  
...  
Keyword(s):  
Conduction System ◽  
Atrioventricular Conduction ◽  
Alligator Mississippiensis ◽  
Ventricular Septum ◽  
Heart Rates ◽  
Conduction Pathway ◽  
Atrioventricular Bundle ◽  
Rapid Activation ◽  
Ventricular Conduction ◽  
Purkinje Network

Mammals and birds have a specialized cardiac atrioventricular conduction system enabling rapid activation of both ventricles. This system may have evolved together with high heart rates to support their endothermic state (warm-bloodedness) and is seemingly lacking in ectothermic vertebrates from which first mammals then birds independently evolved. Here, we studied the conduction system in crocodiles (Alligator mississippiensis), the only ectothermic vertebrates with a full ventricular septum. We identified homologues of mammalian conduction system markers (Tbx3-Tbx5, Scn5a, Gja5, Nppa-Nppb) and show the presence of a functional atrioventricular bundle. The ventricular Purkinje network, however, was absent and slow ventricular conduction relied on trabecular myocardium, as it does in other ectothermic vertebrates. We propose the evolution of the atrioventricular bundle followed full ventricular septum formation prior to the development of high heart rates and endothermy. In contrast, the evolution of the ventricular Purkinje network is strongly associated with high heart rates and endothermy.

scholarly journals Stroke due to Thromboembolism from Congenital Aneurysm of Ventricular Septum

2008 ◽  
Vol 7 (1) ◽  
pp. 43-44
Author(s):  
Shashank Sharma ◽  
◽  
Ajit Thomas ◽  
Aram Baghomian ◽  
Nick Waterfield ◽  
...  
Keyword(s):  
Risk Factors ◽  
Family History ◽  
Young Patients ◽  
Transoesophageal Echocardiography ◽  
Ventricular Septum ◽  
Transthoracic Echocardiogram ◽  
Rigorous Approach ◽  
Cerebrovascular Events ◽  
Membranous Part

We describe the case of a 46-year-old female who presented with recurrent episodes of cerebrovascular events. She had an unremarkable family history and no risk factors for stroke, apart from smoking. A transthoracic echocardiogram with ‘bubble’ contrast was normal. However transoesophageal echocardiography demonstrated an aneurysm of the membranous part of the ventricular septum, representing the likely source of thrombo-embolisation. This case highlights the need for a systematic and rigorous approach to the investigation of young patients with stroke.

IV.—The Atrioventricular Pathway for Conduction of the Impulse for Cardiac Contraction in the Dog

1956 ◽  
Vol 63 (1) ◽  
pp. 71-84 ◽  
Author(s):  
Francis Davies ◽  
E. T. B. Francis ◽  
D. R. Wood ◽  
E. A. Johnson
Keyword(s):  
Right Ventricle ◽  
Direct Evidence ◽  
Cardiac Contraction ◽  
Ventricular Septum ◽  
Significant Delay ◽  
Purkinje Fibres ◽  
Atrioventricular Bundle ◽  
The Right ◽  
Perfused Hearts ◽  
Experimental Injury

SynopsisIt is generally believed that in mammals the impulse for cardiac contraction is conveyed from the atria to the ventricles by the atrioventricular bundle and its branches. This belief is mainly based on the A-V. dissociation which is found to follow experimental injury of the bundle. Since the bundle contains nerves, as well as specialized muscular elements, these experiments do not conclusively prove which structures, nerves or muscle, actually conduct the impulse. In the dog it has been previously shown that the right limb of the bundle is not usually accompanied by nerves, and in the present work the attempt was made by means of very small incisions to cut the muscle (Purkinje) fibres of the limb without damaging nerves in the ventricular septum, the effect on the electrocardiogram being noted. In 5 out of 38 perfused hearts of dogs the experiment was successful, and resulted in a significant delay in the contraction of the right ventricle relative to that of the left. The experiments also revealed that very considerable damage can be inflicted on the nerves in the ventricular septum without altering the electrocardiogram, so long as the limb itself is not injured. The results are regarded as providing direct evidence that the cardiac impulse in the dog is transmitted to the right ventricle by the muscular elements of the right limb of the bundle, and it is submitted that there would seem to be no valid reason for supposing that conduction throughout the A-V. bundle and its limbs is other than myogenic.

The Formation, Structure, Distribution and Frequency of Nuclear Pores

1971 ◽  
Vol 29 ◽  
pp. 518-519
Author(s):  
G. G. Maul
Keyword(s):  
Nuclear Pore Complex ◽  
Nuclear Membrane ◽  
Dynamic Structure ◽  
Nuclear Pore ◽  
Nuclear Pores ◽  
Filter Function ◽  
Etching Technique ◽  
Selective Filter ◽  
Membranous Part

The chromatin of eukaryotic cells is separated from the cytoplasm by a double membrane. One obvious structural specialization of the nuclear membrane is the presence of pores which have been implicated to facilitate the selective nucleocytoplasmic exchange of a variety of large molecules. Thus, the function of nuclear pores has mainly been regarded to be a passive one. Non-membranous diaphragms, radiating fibers, central rings, and other pore-associated structures were thought to play a role in the selective filter function of the nuclear pore complex. Evidence will be presented that suggests that the nuclear pore is a dynamic structure which is non-randomly distributed and can be formed during interphase, and that a close relationship exists between chromatin and the membranous part of the nuclear pore complex.Octagonality of the nuclear pore complex has been confirmed by a variety of techniques. Using the freeze-etching technique, it was possible to show that the membranous part of the pore complex has an eight-sided outline in human melanoma cells in vitro. Fibers which traverse the pore proper at its corners are continuous and indistinguishable from chromatin at the nucleoplasmic side, as seen in conventionally fixed and sectioned material. Chromatin can be seen in octagonal outline if serial sections are analyzed which are parallel but do not include nuclear membranes (Fig. 1). It is concluded that the shape of the pore rim is due to fibrous material traversing the pore, and may not have any functional significance. In many pores one can recognize a central ring with eight fibers radiating to the corners of the pore rim. Such a structural arrangement is also found to connect eight ribosomes at the nuclear membrane.

scholarly journals Congenital Aneurysm of the Membranous Portion of the Ventricular Septum

Circulation ◽  
1964 ◽  
Vol 30 (2) ◽  
pp. 223-226 ◽  
Author(s):  
RICHARD W. CAMPBELL ◽  
E. F. STEINMETZ ◽  
CHARLES H. HELMEN
Keyword(s):  
Ventricular Septum

Survival With Respect to Morphology in Pulmonary Atresia and Intact Ventricular Septum in Sweden

2021 ◽  
Vol 12 (1) ◽  
pp. 27-34
Author(s):  
Stina Manhem ◽  
Katarina Hanséus ◽  
Håkan Berggren ◽  
Britt-Marie Ekman-Joelsson
Keyword(s):  
Pulmonary Atresia ◽  
Early Time ◽  
Ventricular Septum ◽  
Intact Ventricular Septum ◽  
Early Group ◽  
Time Period ◽  
Medical Reports ◽  
One Year ◽  
Survival Risk ◽  
Late Group

Background: Patients born with pulmonary atresia and intact ventricular septum represent a challenge to pediatric cardiologists. Our objective was to study changes in survival with respect to morphology in all children born with pulmonary atresia and intact ventricular septum in Sweden during 36 years. Methods: A retrospective, descriptive study based on medical reports and echocardiographic examinations consisting of those born between 1980 and 1998 (early group) and those born between 1999 and 2016 (late group). Results: The cohort consists of 171 patients (early group, n = 86 and late group, n = 85) yielding an incidence of 4.35 and 4.46 per 100,000 live births, respectively. One-year survival in the early group was 76% compared to 92% in the late group ( P = .0004). For patients with membranous atresia, one-year survival increased from 78% to 98%, and for muscular pulmonary atresia, from 68% to 85%. In patients with muscular pulmonary atresia and ventriculocoronary arterial communications, there was no significant increase in survival. Risk factors for death were being born in the early time period hazard ratio (HR), 6; 95% CI (2.33-14.28) P = .0002, low birth weight HR, 1.26; 95% CI (1.14-1.4) P < .0001 and having muscular pulmonary atresia HR, 3.74; 95% CI (1.71-8.19) P = .0010. Conclusion: The incidence of pulmonary atresia and intact ventricular septum remained unchanged during the study period. Survival has improved, especially for patients with membranous pulmonary atresia, while being born with muscular pulmonary atresia is still a risk factor for death. To further improve survival, greater focus on patients with muscular pulmonary atresia and ventriculocoronary arterial communications is required.

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