首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   45篇
  免费   2篇
耳鼻咽喉   1篇
儿科学   7篇
临床医学   20篇
内科学   12篇
特种医学   1篇
外科学   3篇
预防医学   1篇
药学   1篇
肿瘤学   1篇
  2024年   1篇
  2019年   6篇
  2018年   9篇
  2017年   4篇
  2015年   1篇
  2014年   9篇
  2013年   7篇
  2012年   1篇
  2011年   1篇
  2010年   2篇
  2009年   1篇
  2007年   2篇
  2006年   1篇
  1997年   1篇
  1986年   1篇
排序方式: 共有47条查询结果,搜索用时 15 毫秒
11.

Objectives

Mitral valve replacement (MVR) in young children is limited by the lack of small prostheses. Our institution began performing MVR with modified, surgically placed, stented jugular vein grafts (Melody valve) in 2010. We sought to describe key echocardiographic features for pre- and postoperative assessment of this novel form of MVR.

Methods

The pre- and postoperative echocardiograms of 24 patients who underwent Melody MVR were reviewed. In addition to standard measurements, preoperative potential measurements of the mitral annulus were performed whereby dimensions were estimated for Melody sizing. A ratio of the narrowest subaortic region in systole to the actual mitral valve dimension (SubA:MV) was assessed for risk of postoperative left ventricular outflow tract obstruction (LVOTO).

Results

Melody MVR was performed at a median of 8.5 months (5.6 kg) for stenosis (5), regurgitation (3), and mixed disease (16). Preoperatively, actual mitral z scores measured hypoplastic (median ?3.1 for the lateral [lat] dimension; ?2.1 for the anteroposterior [AP] dimension). The potential measurements often had normal z scores with fair correlation with intraoperative Melody dilation (ρ = 0.51 and 0.50 for lat and AP dimensions, respectively, both P = .01). A preoperative SubA:MV <0.5 was associated with postoperative LVOTO, which occurred in 4 patients. Postoperatively, mitral gradients substantially improved, with low values relative to the effective orifice area of the Melody valve. No patients had significant regurgitation or perivalvar leak.

Conclusions

Preoperative echocardiographic measurements may help guide intraoperative sizing for Melody MVR and identify patients at risk for postoperative LVOTO. Acute postoperative hemodynamic results were favorable; however, ongoing assessment is warranted.  相似文献   
12.
Genetic studies have linked the VTI1ATCF7L2 region with risk of multiple cancers. However, findings from these studies were generally inconclusive. We aimed to provide a synopsis of current understanding of associations between variants in the VTI1ATCF7L2 region and cancer susceptibility. We conducted a comprehensive research synopsis and meta‐analysis to evaluate associations between 17 variants in this region and risk of seven cancers using data from 32 eligible articles totaling 224,656 cancer cases and 324,845 controls. We graded cumulative evidence of significant associations using Venice criteria and false‐positive report probability tests. We also conducted analyses to evaluate potential function of these variants using data from the Encyclopedia of DNA Elements (ENCODE) Project. Eight variants showed a nominally significant association with risk of individual cancer (p < 0.05). Cumulative epidemiological evidence of an association was graded as strong for rs7903146 [odds ratio (OR) = 1.05, p = 4.13 × 10?5] and rs7904519 (OR = 1.07, p = 2.02 × 10?14) in breast cancer, rs11196172 (OR = 1.11, p = 2.22 × 10?16), rs12241008 (OR = 1.13, p = 1.36 × 10?10) and rs10506868 (OR = 1.10, p = 3.98 × 10?9) in colorectal cancer, rs7086803 in lung cancer (OR = 1.30, p = 3.54 × 10?18) and rs11196067 (OR = 1.18, p = 3.59 × 10?13) in glioma, moderate for rs12255372 (OR = 1.12, p = 2.52 × 10?4) in breast cancer and weak for rs7903146 (OR = 1.11, p = 0.007) in colorectal cancer. Data from ENCODE suggested that seven variants with strong evidence and other correlated variants might fall within putative functional regions. Collectively, our study provides summary evidence that common variants in the VTI1A and TCF7L2 genes are associated with risk of breast, colorectal, lung cancer and glioma and highlights the significant role of the VTI1ATCF7L2 region in the pathogenesis of human cancers.  相似文献   
13.
14.

Aim

To evaluate echocardiographic indices of pulmonary vascular resistance and right ventricular (RV) function in predicting death or ECMO in congenital diaphragmatic hernia (CDH).

Methods

In this single center study, early (< 48?h) echocardiograms of neonates with CDH (n?=?47) were reviewed by a single reader for the ratio of tricuspid regurgitant velocity to velocity time integral at the pulmonary valve (TRV/VTIpv), TRV2/VTIpv, RV fractional area change (FAC) and tricuspid annular plane systolic excursion (TAPSE). Receiver operating characteristic curves were generated for each parameter to obtain optimal cutoff values.

Results

Infants who died or received ECMO (n?=?30) had significantly higher TRV/VTIpv and TRV2/VTIpv, and lower VTIpv, RV FAC and TAPSE, compared to the 17 survivors without ECMO. For TRV2/VTIpv and TRV/VTI at cutoffs of 1.3 and 0.38 respectively, the sensitivities were 92.3 (95% CI 75–99.1%) and 96 (95% CI 80.4–99.9%), specificities were 78.6 (49.2–95.4%) and 71.4 (42–91.6%), positive predictive values were 89 (75–95.6%) and 86.2 (73.2–93.5%) and negative predictive values were 84.6 (58.5–95.5%) and 90.9 (58.7–98.6%).

Conclusion

Early echocardiographic evidence of pulmonary hypertension and RV dysfunction predicts outcome in CDH. Further studies utilizing these indices to guide therapeutic decision-making are warranted.

Level of evidence

Level 1 for diagnostic study  相似文献   
15.
Objectives. This study sought to assess the accuracy of Doppler echocardiographic techniques for the determination of right heart catheterization hemodynamic variables in patients with advanced heart failure and in potential heart transplant recipients.

Background. Doppler echocardiographic techniques permit the noninvasive acquisition of hemodynamic variables traditionally used for the assessment of patients with advanced heart failure and potential heart transplant candidates. However, the accuracy of these techniques has not been sufficiently well documented for clinical application in individual patients.

Methods. Echocardiographic data required for estimation of mean right atrial, pulmonary artery and mean left atrial pressures and cardiac output were obtained. Right heart catheterization was performed immediately after Doppler echocardiographic data were acquired, before any intervention that might have altered the subject’s hemodynamic status.

Results. A complete Doppler echocardiographic hemodynamic data set was acquired in 21 (84%) of 25 subjects. For all variables, invasive and noninvasive hemodynamic values were highly correlated (p < 0.001), with minimal bias and narrow 95% confidence limits. An algorithm constructed from the noninvasive hemodynamic variable values identified all patients with adverse pulmonary vascular hemodynamic variables (i.e., transpulmonary gradient ≥12 mm Hg, pulmonary vascular resistance ≥3 Wood units or pulmonary vascular resistance index ≥6 Wood units × m2). This algorithm identified 12 (71%) of 19 patients for whom right heart catheterization was unnecessary.

Conclusions. Doppler echocardiographic estimates of hemodynamic variables in patients with advanced heart failure are accurate and reproducible. This noninvasive methodology may assist with monitoring and optimization of medical therapy in patients with advanced heart failure and may obviate the need for routine right heart catheterization in potential heart transplant candidates.  相似文献   

16.
17.
Aim of the study: To compare three different methods for obtaining interventricular-(VV) interval optimization. Methods: A total of 30 patients undergoing cardiac resynchronization therapy (CRT) were enrolled. All the patients underwent VV-interval optimization performed with three different echocardiographic methods at seven different settings: simultaneous right (RV) and left (LV) ventricular pacing, LV stimulation only, LV preexcitation (LV+20,+40,+60 ms, respectively), RV preexcitation (RV+20 and+40 ms, respectively). Optimal VV delay was selected by: (1) measuring the aortic velocity time integral (VTI method); (2) measuring the time to maximum delay between septal and lateral longitudinal motion in the four-chamber view (velocity method); and (3) measuring the segment with maximal temporal difference of peak circumferential strain in short-axis view at papillary muscles level, (strain method). Velocity and strain methods measurements were obtained relying on two-dimensional ultrasound border tracking algorithm thus providing angle-independent measurements. Results: Immediately after CRT, VTI, maximum peak circumferential strain delay and maximum septal-to-lateral delay were significantly improved (P < 0.001). Particularly, VV-interval optimization determined a further improvement of these indices as compared to the other VV settings (P < 0.001). Furthermore, a substantial concordance was found between the optimal VV interval obtained according to the VTI method and velocity method (k = 0.68), between the optimal VV interval obtained according to the VTI method and strain method (k = 0.63); and between the optimal VV interval obtained according to the velocity method and strain method (k = 0.71). Conclusions: VV-interval optimization was shown to determine a further benefit beyond CRT. A significant concordance was present between VV programming based on different echocardiographic methods. (Echocardiography 2010;27:38-43)  相似文献   
18.
BACKGROUND: Left ventricular (LV) diastolic dysfunction has been observed in cigarette smokers with coronary artery disease. The aim of the study was to assess LV and right ventricular (RV) diastolic function in healthy, young, and slim smokers before and after smoking one cigarette. MATERIAL AND METHODS: The participants were 66 healthy volunteers (age < 40 years; body mass index < 25 kg/m(2)): 33 smokers (study group [HS]) and 33 nonsmokers (control group). Echocardiographic examination was done in the HS before smoking one cigarette (HS-1) and after smoking one cigarette (HS-2). To assess diastolic function of LV and RV mitral valve flow (MVF), pulmonary venous flow (PVF) and tricuspid valve flow (TVF) were evaluated. RESULTS: MVF early to late phase ratio (E/A) was significantly lower in HS-1 and HS-2 than in the control group. The PVF systolic to diastolic phase ratio (S/D) was significantly higher in HS-1 and HS-2 than in the control group. These changes suggest LV diastolic function impairment in the HS, but the MVF pattern remained within the normal range. PVF S/D showed systolic dominance (S/D > 1) typical for impaired LV relaxation and abnormal for this age group. TVF E/A was significantly lower in HS-2 than in HS-1 and control subjects and suggests RV diastolic dysfunction. CONCLUSIONS: The following conclusion are made: (1) MVF and PVF demonstrate LV relaxation impairment in healthy smokers before and after smoking one cigarette; (2) the assessment of PVF is a good method reflecting LV diastolic function changes, even when MVF remains normal; and (3) TVF shows RV relaxation impairment after smoking one cigarette in healthy smokers.  相似文献   
19.
20.
The impact of one ventricle on the adjacent ventricle plays a key role in cardiac function. Ventricular-ventricular interactions are based on the arrangement in-series of the circulation and common pericardium, interventricular septum, and myocardial tracts. Imaging, in particular echocardiography, plays a central role in characterizing these interactions through geometric indices, septal configuration and motion, Doppler flow, timing of events in the ventricles and alterations in strain, remodeling, and diastolic filling with altered loading of the contralateral ventricle. Although standard echocardiography techniques are usually adequate to image ventricular-ventricular interactions, recent developments in automation, post-processing, and advanced techniques (e.g., 3-dimensional) could improve detection and understanding of interventricular interactions. Imaging findings must be analyzed in the context of the pathophysiology to correctly assess and understand ventricular-ventricular interactions. This paper reviews the imaging of ventricular-ventricular interactions in acquired and congenital heart disease, demonstrating their importance in a wide array of conditions.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号