| 1. |
- Henein, Michael Y., et al.
(författare)
-
Aortic valve
- 2012. - 2
-
Ingår i: Clinical echocardiography. - London : Springer. - 9781848825215 - 9781848825208 ; , s. 33-62
-
Bokkapitel (refereegranskat)abstract
- The aortic valve is a passive valve made up of three leaflets which assume the shape of half moons (semi-lunar). Opposite to the mitral valve, there is no true aortic fibrous annulus but a complex root made up of the aortic wall sinuses, left ventricular myocardium, and interleafletfibrous triangles. The ostia of the coronary arteries are located within the aortic sinuses. The sinotubular junction is an important anatomic landmark for surgical procedures. It may be that the leaflets of the aortic valve are not passive as they are rich in different types of nerve endings. The function and role of these “nerves” remain obscure.
|
|
| 2. |
- Henein, Michael Y., et al.
(författare)
-
Cardiac tumors
- 2012. - 2
-
Ingår i: Clinical echocardiography. - London : Springer. - 9781848825215 - 9781848825208 ; , s. 239-250
-
Bokkapitel (refereegranskat)abstract
- Cardiac tumors are rarely suspected clinically but usually appear as unexpected fi ndings when patients are investigated for syncope, breathlessness, thromboembolism, or constitutional manifestations such as congestive heart failure or pulmonary hypertension [1]. Transthoracic echocardiography provides a great opportunity to identify tumors that are clinically silent [2], although extension to extra cardiac structures should be further investigated by transesophageal echocardiography [3], CT scanning, or CMR. Benign tumors form approximately 80% of all cardiac tumors, 70% of which are myxomas [4].
|
|
| 3. |
- Henein, Michael Y., et al.
(författare)
-
Coronary artery disease
- 2012. - 2
-
Ingår i: Clinical echocardiography. - London : Springer. - 9781848825215 - 9781848825208 ; , s. 115-147
-
Bokkapitel (refereegranskat)abstract
- Anomalous origin of the left coronary artery from the pulmonary trunk usually presents in early infancy with congestive cardiac failure due to ischemic myocardial dysfunction. The diagnosis can usually be made by parasternal short axis sections of the great arteries. The most characteristic finding is reversed flow in the left coronary artery demonstrated by color flow Doppler. Usually the anomalous coronary artery connects to the pulmonary trunk at one of the sinuses, but in some cases the connection may be to the more distal pulmonary arteries. A less common presentation of this condition is in late childhood or early adult life, usually with left ventricular dysfunction and mitral regurgitation. There is almost always reversed blood flow in the left coronary artery representing a left to right shunt from the right coronary artery into the pulmonary trunk.
|
|
| 4. |
- Henein, Michael Y., et al.
(författare)
-
Mitral valve
- 2012. - 2
-
Ingår i: Clinical echocardiography. - London : Springer. - 9781848825215 - 9781848825208 ; , s. 1-32
-
Bokkapitel (refereegranskat)abstract
- The mitral valve is composed of two leaflets, an annulus, chordae tendineae, and two papillary muscles. The anterior (aortic) leaflet is attached to the root of the aorta in direct continuity with the aortic valve and the membranous septum, and has a rectangular shape involving one-third of the circumference of the annulus. The posterior leaflet is continuous with the posterior wall of the left atrium and is longer than the anterior leaflet occupying two-thirds of the circumference of the mitral annulus.
|
|
| 5. |
- Henein, Michael Y., et al.
(författare)
-
Pulmonary valve
- 2012. - 2
-
Ingår i: Clinical echocardiography. - London : Springer. - 9781848825215 - 9781848825208 ; , s. 81-92
-
Bokkapitel (refereegranskat)abstract
- The pulmonary valve lies anterior and to the left of the aortic valve. The three pulmonary leafl ets assume the shape of half moons (semi-lunar) and are similar but usually not equal in size. The right and left coronary sinuses of the aorta always face the pulmonary valve. The leafl ets are thinner and more delicate than the aortic leafl ets. Unlike the aortic valve, the pulmonary valve sits on a complete muscular ring of the infundibulum and is not in direct continuity with the tricuspid valve. It is thickest along the closing edge. The delicate pocket-like leaflets are formed primarily of collagen, and they, therefore, open and close passively, with little elastic recoil. In the middle of the free edge of each leafl et is a fi brous mound, the nodule of Arrantius. Coaption of the three nodules ensures complete central closure of the valve orifi ce during ventricular diastole.
|
|
| 6. |
- Henein, Michael Y., et al.
(författare)
-
Tricuspid valve
- 2012. - 2
-
Ingår i: Clinical echocardiography. - London : Springer. - 9781848825215 - 9781848825208 ; , s. 63-79
-
Bokkapitel (refereegranskat)abstract
- The morphologically right atrioventricular valve has three leaflets (tricuspid): septal, inferior (mural), and anterosuperior which are separated from each other by anteroseptal, superoinferior, and inferoseptal commissures, respectively. The inferior leaflet takes its origin exclusively from the diaphragmatic parietal wall of the ventricle and is often called the mural leaflet. Each commissure is usually supported by the corresponding papillary muscle. The most characteristic and distinguishing feature of the tricuspid valve is the direct attachment of the cords from the septal leaflet to the septum.
|
|
| 7. |
- Kim, Keunho J., et al.
(författare)
-
Small Region, Big Impact : Highly Anisotropic Lyman-continuum Escape from a Compact Starburst Region with Extreme Physical Properties
- 2023
-
Ingår i: Astrophysical Journal Letters. - 2041-8205 .- 2041-8213. ; 955:1
-
Tidskriftsartikel (refereegranskat)abstract
- Extreme, young stellar populations are considered to be the primary contributor to cosmic reionization. How the Lyman continuum (LyC) escapes these galaxies remains highly elusive, and it is challenging to observe this process in actual LyC emitters without resolving the relevant physical scales. We investigate the Sunburst Arc, a strongly lensed LyC emitter at z = 2.37 that reveals an exceptionally small-scale (tens of parsecs) region of high LyC escape. The small (<100 pc) LyC-leaking region has extreme properties: a very blue UV slope (β = −2.9 ± 0.1), a high ionization state ([O iii] λ5007/[O ii] λ3727 = 11 ± 3 and [O iii] λ5007/Hβ = 6.8 ± 0.4), strong oxygen emission (EW([O iii]) = 1095 ± 40 Å), and a high Lyα escape fraction (0.3 ± 0.03), none of which are found in nonleaking regions of the galaxy. The leaking region's UV slope is consistent with approximately "pure" stellar light that is minimally contaminated by the surrounding nebular continuum emission or extinguished by dust. These results suggest a highly anisotropic LyC escape process such that LyC is produced and escapes from a small, extreme starburst region where the stellar feedback from an ionizing star cluster creates one or more "pencil-beam" channels in the surrounding gas through which LyC can directly escape. Such anisotropic escape processes imply that random sight-line effects drive the significant scatters between measurements of galaxy properties and LyC escape fraction, and that strong lensing is a critical tool for resolving the processes that regulate the ionizing budget of galaxies for reionization.
|
|
| 8. |
- Mainali, Ramesh, et al.
(författare)
-
The Connection Between Galactic Outflows and the Escape of Ionizing Photons
- 2022
-
Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 940:2
-
Tidskriftsartikel (refereegranskat)abstract
- We analyze spectra of a gravitationally lensed galaxy, known as the Sunburst Arc, that is leaking ionizing photons, also known as the Lyman continuum (LyC). Magnification from gravitational lensing permits the galaxy to be spatially resolved into one region that leaks ionizing photons and several that do not. Rest-frame UV and optical spectra from Magellan target 10 different regions along the lensed Arc, including six multiple images of the LyC leaking region and four regions that do not show LyC emission. The rest-frame optical spectra of the ionizing photon emitting regions reveal a blueshifted (ΔV = 27 km s−1) broad emission component (FWHM = 327 km s−1), comprising 55% of the total [O iii] line flux, in addition to a narrow component (FWHM = 112 km s−1), suggesting the presence of strong highly ionized gas outflows. This is consistent with the high-velocity ionized outflow inferred from the rest-frame UV spectra. In contrast, the broad emission component is less prominent in the nonleaking regions, comprising ∼26% of total [O iii] line flux. The high-ionization absorption lines are prominent in both the leaker and the nonleaker, but the low-ionization absorption lines are very weak in the leaker, suggesting that the line-of-sight gas is highly ionized in the leaker. Analyses of stellar wind features reveal that the stellar population of the LyC leaking regions is considerably younger (∼3 Myr) than that of the nonleaking regions (∼12 Myr), emphasizing that stellar feedback from young stars may play an important role in ionizing photon escape.
|
|
| 9. |
- Seale, Anna N., et al.
(författare)
-
Total Anomalous Pulmonary Venous Connection Morphology and Outcome From an International Population-Based Study
- 2010
-
Ingår i: Circulation. - 1524-4539. ; 122:25, s. 237-2718
-
Tidskriftsartikel (refereegranskat)abstract
- Background-Late mortality after repair of total anomalous pulmonary venous connection is frequently associated with pulmonary venous obstruction (PVO). We aimed to describe the morphological spectrum of total anomalous pulmonary venous connection and identify risk factors for death and postoperative PVO. Methods and Results-We conducted a retrospective, international, collaborative, population-based study involving all 19 pediatric cardiac centers in the United Kingdom, Ireland, and Sweden. All infants with total anomalous pulmonary venous connection born between 1998 and 2004 were identified. Cases with functionally univentricular circulations or atrial isomerism were excluded. All available data and imaging were reviewed. Of 422 live-born cases, 205 (48.6%) had supracardiac, 110 (26.1%) had infracardiac, 67 (15.9%) had cardiac, and 37 (8.8%) had mixed connections. There were 2 cases (0.5%) of common pulmonary vein atresia. Some patients had extremely hypoplastic veins or, rarely, discrete stenosis of the individual veins. Sixty (14.2%) had associated cardiac anomalies. Sixteen died before intervention. Three-year survival for surgically treated patients was 85.2% (95% confidence interval 81.3% to 88.4%). Risk factors for death in multivariable analysis comprised earlier age at surgery, hypoplastic/stenotic pulmonary veins, associated complex cardiac lesions, postoperative pulmonary hypertension, and postoperative PVO. Sixty (14.8%) of the 406 patients undergoing total anomalous pulmonary venous connection repair had postoperative PVO that required reintervention. Three-year survival after initial surgery for patients with postoperative PVO was 58.7% (95% confidence interval 46.2% to 69.2%). Risk factors for postoperative PVO comprised preoperative hypoplastic/stenotic pulmonary veins and absence of a common confluence. Conclusions-Preoperative clinical and morphological features are important risk factors for postoperative PVO and survival. (Circulation. 2010;122:2718-2726.)
|
|
| 10. |
- Seale, Anna N., et al.
(författare)
-
Total anomalous pulmonary venous connection: Outcome of postoperative pulmonary venous obstruction
- 2013
-
Ingår i: Journal of Thoracic and Cardiovascular Surgery. - : Elsevier BV. - 1097-685X .- 0022-5223. ; 145:5, s. 1255-1262
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: Pulmonary venous obstruction (PVO) is an important cause of late mortality in total anomalous pulmonary venous connection (TAPVC). We aimed to describe current practices for the management of postoperative PVO and the efficacy of the different interventional procedures. Methods: We conducted a retrospective international collaborative population-based study involving 19 pediatric cardiac centers in the United Kingdom, Ireland, and Sweden. Patients with TAPVC born between January 1, 1998, and December 31, 2004, were identified. Patients with functionally univentricular circulation or atrial isomerism were excluded. All available data and images were reviewed. Results: Of 406 patients undergoing repair of TAPVC, 71 (17.5%) had postoperative PVO. The diagnosis was made within 6 months of surgery in 59 (83%) of the 71 patients. In 12, serial imaging documented change in appearance of the pulmonary veins. Good-sized pulmonary veins can progress to diffusely small veins and rarely atresia. Patients presenting after 6 months had less severe disease; all are alive at most recent follow-up. Fifty-six (13.8%) of 406 patients underwent intervention for postoperative PVO: 44 had surgical treatment and 12 had an initial catheter intervention. One half underwent 1 or more reinterventions. Three-year survival for patients with postoperative PVO was 58.7%(95% confidence intervals, 46.2%-69.2%) with a trend that those having a surgical strategy did better (P = .083). Risk factors for death included earlier presentation after TAPVC repair, diffusely small pulmonary veins at presentation of postoperative PVO, and an increased number of lung segments affected by obstruction. Conclusions: Postoperative PVO tends to appear in the first 6 months after TAPVC repair and can be progressive. Early intervention for PVO may be indicated before irreversible secondary changes occur. (J Thorac Cardiovasc Surg 2013;145:1255-62)
|
|
