الفهرس 
Chapter 1:Right ventricleOnly 14 pages are availabe for public view
 |  | from | 32 |  |  |
| | | from | 32 | | |
Abstract
RV has historically received less attention than LV, yet RV dysfunction is associated with adverse outcomes in patients with congenital heart disease. RV adaptation to disease is complex and depends on many factors. The most important factors appear to be the type and severity of myocardial injury or stress, the time course of the disease (acute or chronic), and the time of onset of the disease process. As compared with the left ventricle (LV), the unique features of the RV and its complex geometry, its wider range of loading conditions and its greater heterogeneity of regional function made it difficult to find a simple , reliable , cheap and objective measure for assessment of its function. TDI is a new technique that enables assessment of regional myocardial deformation by assessment of strain and strain rate. 2D Speckle tracking echocardiography is an angle-independent technique that may allow an accurate assessment of segmental myocardial deformation. This study was designed to evaluate RV function in patients with congenital Lt to Rt shunt before and 3 month after they undergo transcatheter device closure of their shunts using 2D speckle tracking echocardiography based strain and strain rate imaging. 34 patients were enrolled in the study who were divided into 3 groups :11 patient in PDA group, 8 patients in VSD group and 15 patients in ASD group, comparison was held between the group and itself before and 3 month after device closure. Participants in the study were subjected to full history taking, thorough clinical examination, 12 leads ECG, 2D echocardiography, Mmode and Doppler examination were performed , LVIDd , LVIDs , LA ,AO,MAPSE, TAPSE,RVFAC, QP/QS calculation . PAP measurement via TR jet also Tricuspid annular TDI was performed. Strain and strain rate values of RV free wall and septum were measured by 2D STE. Results of the current study showed that: PDA and VSD groups( sharing nearly the same hemodynamics) : Mildly elevated pulmonary artery pressure was associated with reduced RV strain and strain rate values both global and segmental that were increased after shunt closure and reduction of PAP values taking in consideration that both values pre and post stand beyond normal values ( i:e RV function is good in both also signifies the role of deformation imaging in early detection of subtle changes in RV mechanics when exposed to pressure load) , diastolic function also improved and this is in company with reverse remodeling that resulted in increase in the RVFAC , TAPSE , S wave velocity at tricuspid annulus, reduction of volume load on LV and LA so reduction in their dimensions after closure also MAPSE was reduced . IVRT was measurable in cases having higher PAP values indicating its sensitivity to pressure load . In ASD group: Volume overload on RV and according to Frank Starling law leads to increased contractility provided that function is preserved , so volume load in ASD cases leads to increased deformation and deformation rate values as evidenced in significant reduction of strain and strain rate values after volume load elimination and ASD closure also RVFAC reflecting diastolic RV dimensions was reduced as a remodeling process, TAPSE , S wave tricuspid annulus also reduced after closure explained by the same role .Reverse remodeling of LV and increase in LVEDd after closure also MAPSE. RV shows increment in strain and strain rate values from base to apex . RV free wall values are higher than septal values . Strain and strain rate values gained via 2D speckle tracking echocardiography are load dependent parameter of contractility as evidenced in this study testing RV performance under both pressure and volume load . The value of these parameters of contractility assessment comes from their ability to detect subtle changes in mechanics and deformation that are not easily detected by conventional measures.