Clinical anatomy of human heart atria and interatrial septum — anatomical basis for interventional cardiologists and electrocardiologists. Part 2: left atrium

ObjectivesWe sought to clarify the variations in the anatomy of the superior cavoatrial junction and anomalously connected pulmonary veins in patients with superior sinus venosus defects using computed tomographic (CT) angiography.MethodsCT angiograms of 96 consecutive patients known to have superior sinus venosus defects were analysed.ResultsThe median age of the patients was 34.5 years. In seven (7%) patients, the defect showed significant caudal extension, having a supero-inferior dimension greater than 25 mm. All patients had anomalous connection of the right superior pulmonary vein. The right middle and right inferior pulmonary vein were also connected anomalously in 88 (92%) and 17 (18%) patients, respectively. Anomalous connection of the right inferior pulmonary vein was more common in those with significant caudal extension of the defect (57% vs 15%, p=0.005). Among anomalously connected pulmonary veins, the right superior, middle, and inferior pulmonary veins were committed to the left atrium in 6, 17, and 11 patients, respectively. The superior caval vein over-rode the interatrial septum in 67 (70%) patients, with greater than 50% over-ride in 3 patients.ConclusionAnomalous connection of the right-sided pulmonary veins is universal, but is not limited to the right upper lobe. Not all individuals have over-riding of superior caval vein. In a minority of patients, the defect has significant caudal extension, and anomalously connected pulmonary veins are committed to the left atrium. These findings have significant clinical and therapeutic implications.

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Abstract 18782: Regional Action Potential Heterogeneity in the Murine Pitx2c Deficient Left Atrium

Circulation ◽

10.1161/circ.130.suppl_2.18782 ◽

2014 ◽

Vol 130 (suppl_2) ◽

Author(s):

Andrew P Holmes ◽

Ting Yu ◽

Fahima Syeda ◽

Nigel A Brown ◽

Larissa Fabritz ◽

...

Keyword(s):

Action Potential ◽

Left Atrium ◽

Lateral Wall ◽

Interatrial Septum ◽

The Other ◽

Wild Type ◽

Genetic Abnormalities ◽

Mapping System ◽

Pitx2 Gene ◽

Partial Depletion

Introduction and hypothesis: Genetic abnormalities close to the Pitx2 gene correlate more strongly with atrial fibrillation (AF) than any other genetic modification. It is known that Pitx2c mRNA is expressed in the adult left atrium (LA), but its relevance for the electrical integrity of cardiomyocytes throughout the atria remains unresolved. We therefore compared regional action potential (AP) morphology in PITX2c +/- and wild type (WT) littermate mice. Methods: Transmembrane (T) and optical (O) APs were recorded from superfused intact, isolated LA paced at 100ms. TAPs were recorded from three distinct regions on the LA epicardium: 1) the junction with the interatrial septum (S), 2) the medial muscular dome (M) and 3) the lateral wall (L). OAPs were recorded using a custom murine atrial optical mapping system using the Hamamatsu ORCA flash 4 and Di-4-Anepps. Results: OAPs were shorter in Pitx2c deficient LA (AP duration (APD70); WT 13±2ms, n=4 LA vs Pitx2c +/- 9±1ms, n=4 LA, all data as mean±SEM, p<0.05). Simultaneous recordings of OAPs from multiple LA regions showed an AP gradient with longer OAPs at the septum than at the lateral wall, in both genotypes. In WT LA, TAPs were longer and of greater amplitude at the septum than in the other two regions (APD90; S 26±1ms, M 19±1mV and L 19±1ms, APA; S 81±1mV, M 76±2mV and L 76±2mV, n=6 LA, p<0.05). In Pitx2c +/- , TAPs were shorter than WT in all three regions tested and exhibited the same regional patterning (S 20±1ms, M 15±1ms and L 16±1, n=7 LA, p<0.05). The regional AP amplitude gradient was not apparent, or at least shifted more towards the lateral wall, in PITX2c +/- atria (APA; S 77±2mV, M 76±3mV and L 74±2mV, n=7 LA, ns). Conclusion: Partial depletion in Pitx2c mRNA expression causes a uniform APD shortening throughout the LA and loss of regional changes in AP amplitude. Identification of the targets downstream of Pitx2 accounting for these changes will help to better understand the mechanisms conveying AF due to reduced Pitx2 function.

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Responses to phenethylamines and nicotine and histology of turtle atria

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1959.197.4.747 ◽

1959 ◽

Vol 197 (4) ◽

pp. 747-751 ◽

Cited By ~ 3

Author(s):

Sister Marie Therese Dimond

Keyword(s):

Effective Dose ◽

Left Atrium ◽

Rate Increase ◽

Interatrial Septum ◽

Chrysemys Picta ◽

Painted Turtle ◽

Conducting Tissue ◽

Amplitude Increase ◽

The Right ◽

Chromaffin Tissue

Epinephrine (E), norepinephrine (NE), tyramine (T) and nicotine were tested at various dosage levels on different atrial regions of the heart of the eastern painted turtle, Chrysemys picta picta (Schneider), and the median effective dose determined. The three phenethylamines acted according to the following pattern in their effect on rate increase, amplitude increase, and inhibition of tonus waves: E > NE > T, except for amplitude increase in the left atrium and tonus wave inhibition in both atria, where E and NE were equal. The right sino-atrium and left atrium differed in sensitivity to the drugs. The various responses, including treppe, are consonant with the theory of the release from the tissues of a potentiating substance and a depressing substance. Histological stains for chromaffin tissue, a possible source of potentiating substance, were negative, but a differentially stained type of cardiac muscle, a possible conducting tissue, is present in regions of the sinus venosus and both atria and at the base of the interatrial septum.

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The Clinical Anatomy of the Coronary Arteries: An Anatomical Study on 100 Human Heart Dissectionsby Horia Muresian

Clinical Anatomy ◽

10.1002/ca.20868 ◽

2009 ◽

Vol 22 (8) ◽

pp. 949-949 ◽

Cited By ~ 1

Author(s):

Daniel O. Graney

Keyword(s):

Coronary Arteries ◽

Human Heart ◽

Anatomical Study ◽

Clinical Anatomy

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Comparative anatomy of the cardiac foramen ovale in the Pinnipedia

Canadian Journal of Zoology ◽

10.1139/z95-100 ◽

1995 ◽

Vol 73 (5) ◽

pp. 850-857 ◽

Cited By ~ 3

Author(s):

Alastair A. Macdonald ◽

Christopher Dixon ◽

Ian L. Boyd

Keyword(s):

Left Atrium ◽

Comparative Anatomy ◽

Pulmonary Veins ◽

Vena Cava ◽

Interatrial Septum ◽

Weddell Seal ◽

Foramen Ovale ◽

Septum Primum ◽

Lobodon Carcinophagus ◽

Short Tunnel

The structure of the cardiac foramen ovale from eight genera of pinnipeds was studied using the scanning electron microscope. Specimens were obtained from fetuses or neonates of the Californian sea lion (Zalophus californianus), Antarctic fur seal (Arctocephalus gazella), walrus (Obenus rosmarus), grey seal (Halichoerus gryphus), ringed seal (Phoca hispida), bearded seal (Erignathus barbatus), Weddell seal (Leptonychotes weddelli), and crabeater seal (Lobodon carcinophagus). In each species, the structure that permits oxygenated blood from the placenta flowing in the caudal vena cava to pass directly into the left side of the heart, the foramen ovale, when viewed from the terminal part of the caudal vena cava had the appearance of the entrance to a short tunnel. A thin fold of tissue, the developed remains of the septum primum, projected from the caudal edge of the foramen ovale into the lumen of the left atrium. It constituted about 75% of the inner surface of the tunnel, and was generally unfenestrated. The wall of the interatrial septum contributed the "floor." The distal end of the tunnel was straight-edged. In most cases the septum primum was long enough to cover the foramen ovale. The siting of pulmonary veins in the roof of the left atrium appeared to be such that drainage from them after birth would press the septum primum over the foramen opening, thereby functionally closing it. Collapses of the tunnel was seen in all the neonatal seals, and in the 1-month-old neonate the fold of tissue was anchored to the interatrial septum along the surface of the crista dividens, which lay in the left atrium. Cellular protrusions and thread formation may play a role in the closure of the foramen ovale.

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A Case of Complex PFO Leading to Ischemic Stroke

The Neurohospitalist ◽

10.1177/1941874415588750 ◽

2015 ◽

Vol 6 (3) ◽

pp. 114-117

Author(s):

Anna Coles ◽

Bradley Haveman-Gould ◽

Muhammad U. Farooq ◽

Kristopher J. Selke ◽

Philip B. Gorelick

Keyword(s):

Left Atrium ◽

Cardiac Cycle ◽

Interatrial Septum ◽

Cardioembolic Stroke ◽

Pulmonary Emboli ◽

Right Heart ◽

Neurological Sequelae ◽

Younger Patient ◽

Septum Primum ◽

Active Flow

Patent foramen ovale (PFO) has been proposed as a mechanism for cardioembolic stroke, especially in younger patient populations. Complex PFOs, with tunnel lengths exceeding 8 mm, lead to a higher risk of neurological sequelae than simple PFOs and may also be harder to detect with transthoracic echocardiography (TTE). In this article, we present a 29-year-old woman who, after polypharmacy overdose, developed deep venous thrombosis and multiple pulmonary emboli (PE) and subsequent cardioembolic stroke. Initial TTE showed intact interatrial septum with late appearance of agitated saline in the left atrium after the seventh cardiac cycle. Subsequent transesophageal echocardiography, after treatment of PE with an intravenous thrombolytic (alteplase) and anticoagulation with heparin, showed a complex PFO with a 19-mm overlap of the septum primum and secundum without active flow. It is suggested that this PFO allowed for flow only in the situation of elevated right heart strain with PE, causing cardioembolic stroke and detection of agitated saline in the left atrium on TTE. However, under normal physiological situations, which resumed after treatment of PE with alteplase and heparin, the PFO did not allow for flow. This case demonstrates the potential importance of recognition of complex PFOs in diagnosis and management of cardioembolic stroke.

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Current ECG Aspects of Interatrial Block

Hearts ◽

10.3390/hearts2030033 ◽

2021 ◽

Vol 2 (3) ◽

pp. 419-432

Author(s):

Antoni Bayés-de-Luna ◽

Miquel Fiol-Sala ◽

Manuel Martínez-Sellés ◽

Adrian Baranchuk

Keyword(s):

Atrial Fibrillation ◽

Left Atrium ◽

Premature Death ◽

Interatrial Septum ◽

P Wave ◽

Junction Zone ◽

Electrical Impulse ◽

Wave Morphology ◽

Atrial Activation ◽

Interatrial Block

Interatrial blocks like other types of block may be of first degree or partial second degree, also named transient atrial block or atrial aberrancy, and third degree or advanced. In first degree, partial interatrial block (P-IAB), the electrical impulse is conducted to the left atrium, through the Bachmann’s region, but with delay. The ECG shows a P-wave ≥ 120 ms. In third-degree, advanced interatrial block (A-IAB), the electrical impulse is blocked in the upper part of the interatrial septum (Bachmann region); the breakthrough to LA has to be performed retrogradely from the AV junction zone. This explains the p ± in leads II, III and aVF. In typical cases of A-IAB, the P-wave morphology is biphasic (±) in leads II, III and aVF, because the left atrium is activated retrogradely and, therefore, the last part of the atrial activation falls in the negative hemifield of leads II, III and aVF. Recently, some atypical cases of A-IAB have been described. The presence of A-IAB is a risk factor for atrial fibrillation, stroke, dementia, and premature death.

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Giant Left Atrial Myxoma Presenting with Cough-Syncope Syndrome

The Heart Surgery Forum ◽

10.1532/hsf.3991 ◽

2021 ◽

Vol 24 (4) ◽

pp. E7090-E712

Author(s):

Esra Ertürk tekin

Keyword(s):

Mitral Valve ◽

Left Ventricle ◽

Left Atrium ◽

Left Atrial ◽

Interatrial Septum ◽

Atrial Myxoma ◽

Transesophageal Echocardiogram ◽

Left Atrial Myxoma ◽

Cardiac Surgeon ◽

The Mean

We report the case of a 41-year-old female patient with symptoms of cerebrovascular accident manifesting with loss of consciousness during episodes of cough. Computed multislice chest tomography showed a 7.3- by 4.15-cm mass in the left atrium. A transesophageal echocardiogram showed a giant mass in the left atrium that passed through the mitral valve to the left ventricle, and severe obstructive stenosis was suggested by the mean transmitral gradient. After a comprehensive assessment of the mass, we decided to perform surgery. The pedunculated and fragile mass was attached to the interatrial septum with its handle, and the majority of it prolapsed through the mitral valve to the left ventricle and became stacked among the mitral valve leaflets. The removed mass was analyzed histopathologically and was found to be a myxoma. It is important for the cardiac surgeon to surgically remove an atrial myxoma because of the risks associated with embolization, including sudden death, as myxoma can block the blood supply from the atrium to the ventricle.

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Composite Solution Procedure for 3-D Flow Simulations on a Multi-Box Grid

Volume 1: Symposia, Parts A and B ◽

10.1115/fedsm2006-98441 ◽

2006 ◽

Author(s):

Larry Chen ◽

Urmila Ghia

Keyword(s):

Reynolds Number ◽

Flow Field ◽

Left Atrium ◽

Numerical Scheme ◽

Human Heart ◽

Complex Geometry ◽

Grid Generation ◽

Flow Simulations ◽

Generation Technique ◽

Flow Division

Fluid flows in biological systems are typically complex, due to factors such as non-Newtonian behavior of biochemical fluids and complex geometry, as well as the interaction of muscles and fluid. With the advent of modern computational technology, these problems are gradually resolved. The present research illustrates two such examples. Grid generation is essential for conducting numerical simulation of fluid flow. In the present research, a new grid generation technique is developed and implemented into a flow solver. This technique enables one to create a grid for complex geometry using only a single computational zone. The flow field can therefore be analyzed without iteration between zones. The numerical scheme developed for solving the grid generation equations is an extension of the traditional three-dimensional Douglass-Gunn Alternating-Direction Implicit (ADI) scheme. A unique feature of the demonstrated grid generation scheme is the concept of multi-box computational domains. In this scheme, the physical domain is mapped onto a multi-box geometry in the computational space, rather than a single box as the traditional methods do. Therefore, the numerical scheme is adjusted accordingly. Flow simulations were performed using the software INS3D, which employs the method of artificial compressibility. This method transforms the Navier-Stokes equations into a system of hyperbolic-parabolic equations, and then marches along the pseudo-time axis until the velocity field becomes divergence-free. Two biological flow problems were analyzed using the aforementioned method. The flow field in an arterial graft as well as in the Left atrium (LA) of the human heart was studied. The effect of Reynolds number and flow-division ratio is examined in the graft problem. The Reynolds number effect is demonstrated via the presence of a helical flow structure and the overall pressure drop. The flow-division ratio alters the flow field in a way that moves the stagnation points. The simulated flow field closely resembles that observed clinically. The steady-state simulation of the flow field in the left atrium of the human heart provided information about the long-term performance of the heart chamber. The simulation demonstrates the existence of low wall shear region, which is therefore susceptible to blood clot formation. This observation also agrees with the clinical findings. In summary, the present research demonstrates application of CFD techniques in the analysis of flow in a biological system. A new grid generation technique is realized, and proved to be useful in simulating these flows. The flow simulation results provide insights into the system, and may be useful for clinical reference.

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