O ften overlooked, and considered the poor relation of the left ventricle, there is increasing interest in the right ventricle particularly with regard to right ventricular failure. Right ventricular function may be impaired as a result of pressure or volume overload, often secondary to right heart valve or muscle pathology. Coronary artery disease may also lead to right ventricular dysfunction when the right coronary artery is occluded. In congenital heart malformations the right ventricle may also be affected, particularly in conditions that have the right ventricle supporting the systemic circulation or it becomes the sole pumping chamber following univentricular repair at surgery. Finally, right-to-left shunting may lead to right ventricular dilatation. Imaging the right ventricle by echocardiography is challenging because of the very particular crescentic shape of the right ventricle wrapping around the left ventricle, but it is important and ought to be part of the standard echocardiographic examination of the heart.To help understand cross sectional imaging of the right ventricle, we first review its location and its component parts, including the tricuspid and pulmonary valves, before discussing echo-anatomic correlations. LOCATIONThe right ventricle in the normal heart is the most anteriorly situated cardiac chamber since it is located immediately behind the sternum. It also marks the inferior border of the cardiac silhouette. In contrast to the near conical shape of the left ventricle, the right ventricle is more triangular in shape when viewed from the front and it curves over the left ventricle. When seen from the apex, the right edge of the right ventricle is sharp, forming the acute margin of the Figure 1 An endocast of a normal heart with right heart chambers coloured blue and left heart chambers coloured red is viewed from different perspectives to display the spatial relationships between cardiac chambers. (A) Viewed from the anterior aspect, the crossover arrangement between left and right ventricular outflow tracts (dotted arrow and open arrow respectively) is apparent. The pulmonary valve (solid arrow) is situated most superiorly. (B) This view from right and anterior shows the triangular shape of the right ventricle delimited by the tricuspid (dotted line) and pulmonary (arrow) valves. (C) Viewed from the apex, the right ventricle is crescentic, wrapping round the left ventricle. The open arrow marks the acute margin. The coronary sinus is related to the inferior wall of the left atrium. (D) This view from the diaphragmatic aspect shows the course of the coronary sinus and the cardiac crux. (E) This four chamber section through a heart shows the off-set arrangement of the hingelines of the tricuspid and mitral valves (arrows) with the tricuspid valve attached closer to the cardiac apex than the mitral valve. The broken lines trace the course of the coronary sinus passing along the inferior aspect of the left atrium. Ao, aorta; CS, coronary sinus; ICV, inferior caval vein; LA, left atrium; LV,...
SUMMARY The mitral annulus is the point at which the atrial and ventricular walls meet the base of the mitral valve cusps. The suggestion that a variant of this arrangement termed "disjunction" was associated with prolapse of the leaflets prompted examination of the mitral atrioventricular junctions in seven normal hearts and six with prolapse owing to floppy mitral valves. A complete cord-like ring of connective tissue that encircled the atrioventricular junction and into which the three components were inserted at the same point was found in only one heart. The remaining hearts all showed a mixture of segments in which either the three components were inserted into a cord or simply met. Disjunction, defined as a separation of the atrial wall-mitral valve junction from the other component, the left ventricular wall, can occur both with and without a cord-like annulus. There was no significant difference in the number of segments around the left atrioventricular junction which showed disjunction in hearts with normal or prolapsing leaflets.The feature termed disjunction is an anatomical variation of the normal morphological characteristics of the left atrioventricular junction. atrial wall-mitral valve junction and the left ventricular attachment.9 They argued that this anomalous feature, through a process of hypermobility of the tension apparatus, could lead to floppiness of the leaflets. This group, however, studied only limited histological sections from a large number of hearts to demonstrate the significant association between so-called "disjunction" and floppy and prolapsed leaflets.It seemed to us that it was important to test their hypothesis by examining in detail the entire atrioventricular junction in a smaller number of hearts. This report describes our findings. Patients and methodsWe examined 13 hearts obtained an necropsy. The mitral valve was normal in seven (from 3 men and 4 women) and floppy in six (from 4 men and 2 women). The specimens of normal hearts came from a group aged 66-80 years (mean 71-9) and those with floppy valves came from a group aged 56-89 years (mean 69-5).
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