scholarly journals Ventricular Septation and Outflow Tract Development in Crocodilians Result in Two Aortas With Bicuspid Semilunar Valves

Author(s):  
Robert Poelmann ◽  
Adriana C. Gittenberger-de Groot ◽  
Charissa Goerdajal ◽  
Nimrat Grewal ◽  
Merijn A.G. de Bakker ◽  
...  

The outflow tract of crocodilians resembles that of birds and mammals as ventricular septation is complete. The arterial anatomy however, presents with a pulmonary trunk originating from the right ventricular cavum, and two aortae originating from either the right or left ventricular cavum. Mixing of blood in crocodilians cannot occur at ventricular level as in other reptiles, but instead takes place at aortic root level by a shunt, the Foramen of Panizza, the opening of which is guarded by two facing semilunar leaflets of both bicuspid aortic valves. Methods. Developmental stages of Alligator mississipiensis, Crocodilus niloticus and Caiman latirostris, have been studied. Results and Conclusions. The outflow tract septation complex can be divided into 2 components. The aorto-pulmonary septum divides the pulmonary trunk from both aortae, whereas the interaortic septum divides the systemic from the visceral aorta. Neural crest cells are most likely involved in the formation of both components. Remodeling of the endocardial cushions and both septa results in the formation of bicuspid valves in all three arterial trunks. The foramen of Panizza originates intracardially as a channel in the septal endocardial cushion.

2020 ◽  
Vol 21 (Supplement_1) ◽  
Author(s):  
C Fiore ◽  
A M F Ali ◽  
T Kemaloglu Oz ◽  
G Cagnazzo ◽  
M Melone ◽  
...  

Abstract A 77-year-old female, known hypertensive and dyslipidemic on treatment presented with three episodes of syncope in the last two months. On examination; there was grade 4/6 harsh systolic murmur on the lateral sternal border. Transthoracic echocardiography was difficult because of mesocardia and abnormal rotation of the heart due to enlarged right sided chambers. There is mild left ventricular hypertrophy with normal ejection fraction, no left sided valvular disease. The right ventricle was hypertrophied and dilated with normal RV function. The pulmonary valve was thickened with significant systolic flow aliasing through the valve with significant regurgitation and huge main pulmonary trunk aneurysm (59 mm at its wideset diameter) (Figure 1). Transthoracic approach did not allow a correct alignment of the Doppler CW and the correct estimate of pulmonary valvulopathy; TEE was performed with a correct visualization of the valve in deep transgastric projection at 90 degrees. The valve was thickened, fibrotic, degenerated with systolic doming of leaflets (Figure 2) and peak systolic gradient ∼ 70 mmHg (Figure 3). 3D reconstruction of the valve showed a tricuspid valve (Figure 4) with a valve area ∼ 0.9 cm2 using planimetry in MPR (Figure 5). CT scan was performed which confirmed the main pulmonary trunk aneurysm ∼ 60 mm (Figure 6). Therefore, in light of the clinical and instrumental picture, the patient was referred to heart team discussion for the plan of surgical intervention. Discussion According to the ESC guidelines for grown up congenital heart disease in 2010, this pulmonary valve should be intervened upon as it is severe symptomatic PS (1), but there are 2 problems with this case; the first is significant associated PR, so no place for balloon dilatation here, the second problem is the pulmonary artery aneurysm (PAA). The dilemma of management of pulmonary PAA is that all the available data are about aortic aneurysms. Indications for intervention for PAA include: Absolute PAA diameter ≥ 5.5 cm, Increase in the diameter of the aneurysm of ≥ 0.5 cm in 6 mo, Compression of adjacent structures, Thrombus formation in the aneurysm sack, Evidence of valvular pathologies or shunt flow Verification of PAH, Signs of rupture or dissection (2). Surgery could include: Aneurysmorrhaphy only decreases the diameter of the vessel (3). Aneurysmectomy and repair or replacement of the right ventricular outflow tract is commonly used technique recently and mostly suits connective tissue disorders (6). Also, Replacement of the PA and the pulmonary trunk with a conduit (Gore-Tex or Dacron tubes, homografts, or xenografts) starting in the right ventricular outflow tract with replacement of the pulmonary valve (4). Conclusion PAA management is currently challenging because there are no clear guidelines on its optimal treatment. The presence of significant pulmonary valve dysfunction could affect the decision making of the associated PAA management. Abstract P180 Figure.


1996 ◽  
Vol 199 (2) ◽  
pp. 359-365 ◽  
Author(s):  
M Axelsson ◽  
C E Franklin ◽  
C O Löfman ◽  
S Nilsson ◽  
G C Grigg

Prolonged submergence imposes special demands on the cardiovascular system. Unlike the situation in diving birds and mammals, crocodilians have the ability to shunt blood away from the lungs, despite having an anatomically divided ventricle. This remarkable cardiovascular flexibility is due in part to three anatomical peculiarities: (1) an 'extra' aorta (the left aorta) that leaves the right ventricle and allows the blood from the right ventricle to take an alternative route into the systemic circulation instead of going to the lungs; (2) the foramen of Panizza, an aperture that connects the right and left aortas at their base immediately outside the ventricle; and (3) a set of connective tissue outpushings in the pulmonary outflow tract in the right ventricle. Using high-resolution angioscopy, we have studied these structures in the beating crocodile heart and correlated their movements with in vivo pressure and flow recordings. The connective tissue outpushings in the pulmonary outflow tract represent an active mechanism used to restrict blood flow into the lungs, thus creating one of the conditions required for a right-to-left shunt. We observed that the foramen of Panizza was obstructed by the medial cusp of the right aortic valve during most of systole, effectively differentiating the left and right aortic blood pressure. During diastole, however, the foramen remained open, allowing pressure equilibration between the two aortas. Contrary to current theories, we found that the left aortic valves were unable to cover the foramen of Panizza during any part of the cardiac cycle, supporting the reversed foramen flow hypothesis. This would ensure a supply of blood to the coronary and cephalic circulation during a complete shut-down of the left side of the heart, such as might occur during prolonged submergence.


1995 ◽  
Vol 269 (5) ◽  
pp. R1133-R1139 ◽  
Author(s):  
G. M. Malvin ◽  
J. W. Hicks ◽  
E. R. Greene

Many different flow patterns have been described through the central circulation of crocodilian reptiles. We tested the hypothesis that the vagus nerve stimulation promotes right-to-left (R-L) shunting in the alligator. Flow patterns were investigated before and during stimulation of the intact left vagus nerve using three methods. 1) Atrial and aortic PO2 were measured simultaneously and continuously by gas probes. 2) Atrial outflows were tracked with a blood tracer (helium). 3) Flows were assessed with echocardiography. Four different flow patterns were observed before vagal stimulation: left ventricular (LV) blood flowed into both the right (RAo) and left (LAo) aortas, whereas right ventricular (RV) blood flowed only into the LAo; both aortas received a mixture of LV and RV blood; only LV blood perfused both aortas; and RV blood flowed into both aortas, but LV blood flowed only into the RAo. During vagal stimulation, both aortas received a mixture of LV and RV blood in half of the animals, and in the other half, both aortas received RV blood, but LV blood flowed only into the RAo. Doppler and contrast echocardiography demonstrated swirling flow in the foramen of Panizza and the base of the LAo during systole. These data indicate that vagal stimulation either maintains or produces R-L shunting, flow patterns are variable, and blood can swirl in the foramen of Panizza and LAo base.


2009 ◽  
Vol 2009 ◽  
pp. 1-3 ◽  
Author(s):  
Ahmad Slim ◽  
John Thurlow ◽  
Jennifer Blevins ◽  
Shaun Martinho ◽  
Brian Markelz

This is the case of an 18 year old active duty soldier with symptoms of exertional chest pressure and syncope who was found to have anomalous origin of the left main coronary artery (LMCA) from the right coronary cusp (RCC) traveling partially between the great vessels before taking a septal approach between the left ventricular outflow tract (LVOT) and the right ventricular outflow tract (RVOT). Anomalous origin of coronary arteries is a rare condition that carries an increased risk of angina, myocardial ischemia, and sudden cardiac death (SCD). Surgical treatment of such anomalies with both high and lower risk features can be challenging, and traditional benefit from surgical correction may not be achieved due to complex anatomy. As evident by our patient, this rare condition even though benign from sudden death standpoint could be debilitating despite best efforts and available resources.


1995 ◽  
Vol 5 (1) ◽  
pp. 78-81
Author(s):  
Eric Rosenthal ◽  
Shakeel A. Qureshi ◽  
Michael Tynan

SummaryA 33-year-old woman known to have tetralogy of Fallot and a straddling tricuspid valve had bilateral systemic-to-pulmonary arterial shunts constructed at the age of six months. She subsequently developed infundibular atresia. Antegrade flow of blood from the right ventricle to pulmonary trunk was re-established by percutaneous laser perforation of the outflow tract, later followed by implantation of a stent.


2015 ◽  
Vol 2015 ◽  
pp. 1-3
Author(s):  
Bortolo Martini ◽  
Nicola Trevisi ◽  
Nicolò Martini ◽  
Li Zhang

A 43-year-old woman presented to the emergency room with a sustained ventricular tachycardia (VT). ECG showed a QRS in left bundle branch block morphology with inferior axis. Echocardiography, ventricular angiography, and cardiac magnetic resonance imaging (CMRI) revealed a normal right ventricle and a left ventricular diverticulum. Electrophysiology studies with epicardial voltage mapping identified a large fibrotic area in the inferolateral layer of the right ventricular wall and a small area of fibrotic tissue at the anterior right ventricular outflow tract. VT ablation was successfully performed with combined epicardial and endocardial approaches.


2003 ◽  
Vol 13 (3) ◽  
pp. 240-247 ◽  
Author(s):  
Litha P. Pepas ◽  
Alexandra Savis ◽  
Annette Jones ◽  
Gurleen K. Sharland ◽  
Robert M.R. Tulloh ◽  
...  

Objective: To document the echocardiographic features of tetralogy of Fallot during fetal and postnatal life. Correlation of echocardiographic findings with the requirement for early intervention prior to definitive repair. Design: Retrospective observational study. Setting: A tertiary fetal cardiology unit. Patients: Fetuses with a diagnosis of tetralogy of Fallot identified from a prospective database between 1 January 1999 and 31 October 2002. Main measures of outcome: Growth of aorta and pulmonary trunk during fetal and postnatal life. Doppler assessment of the great arteries both prenatally and postnatally. Clinical outcome to definitive repair. Results: We identified 25 fetuses with tetralogy of Fallot, 23 having a pulmonary valvar diameter below the normal range at some point during gestation. The ratio of the diameter of the aortic to the pulmonary valve was abnormal in all cases. The pulmonary arterial Doppler velocity was within the normal range in six fetuses at presentation, and elevated in the remainder. In two fetuses, the right ventricular outflow tract was patent during fetal life, but had become atretic at birth. Both of these fetuses had reversal of flow in the arterial duct at presentation during fetal life. In 2 fetuses in whom we showed poor growth of the pulmonary trunk in late gestation, it was necessary to intervene early. The Doppler velocity across the pulmonary valve during fetal life did not differentiate between babies who required early intervention and those who were repaired electively. There was a marked increase in pulmonary arterial Doppler velocity following birth, which became more elevated with age. Of 18 liveborn infants, 17 have survived, with 2 having balloon dilation of the right ventricular outflow tract, and 3 insertion of a Blalock-Taussig shunt prior to definitive repair. Conclusions: In tetralogy of Fallot, features of pulmonary valvar hypoplasia and obstruction are evident during fetal life. Progression of obstruction in the right ventricular outflow tract was observed during fetal life as well as postnatally. Reversal of flow in the arterial duct, and failure of growth of the pulmonary trunk, predicted the need for early surgery to maintain pulmonary blood flow. Parents should be counselled about the possibility of emergency intervention being required after birth. Affected fetuses should be delivered at units with experience of managing the cyanosed newborn.


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