Color Doppler jet area overestimates regurgitant volume when multiple jets are present.

Background: Color Doppler jet area (CDJA) is an important measure used to classify mitral regurgitation (MR) severity. The investigators hypothesized that the presence and configuration of multiple regurgitant jets can alter CDJA quantification for fixed regurgitant volumes. This has relevance to MR assessment prior to the treatment of valves with multiple regurgitant orifices or after surgical or percutaneous double-orifice mitral valve repair.

Reversing blood flows act through klf2a to ensure normal valvulogenesis in the developing heart.

Heart valve anomalies are some of the most common congenital heart defects, yet neither the genetic nor the epigenetic forces guiding heart valve development are well understood. When functioning normally, mature heart valves prevent intracardiac retrograde blood flow; before valves develop, there is considerable regurgitation, resulting in reversing (or oscillatory) flows between the atrium and ventricle. As reversing flows are particularly strong stimuli to endothelial cells in culture, an attractive hypothesis is that heart valves form as a developmental response to retrograde blood flows through the maturing heart.

Rapid three-dimensional imaging and analysis of the beating embryonic heart reveals functional changes during development.

We report an accurate method for studying the functional dynamics of the beating embryonic zebrafish heart. The fast cardiac contraction rate and the high velocity of blood cells have made it difficult to study cellular and subcellular events relating to heart function in vivo. We have devised a dynamic three-dimensional acquisition, reconstruction, and analysis procedure by combining (1) a newly developed confocal slit-scanning microscope, (2) novel strategies for collecting and synchronizing cyclic image sequences to build volumes with high temporal and spatial resolution over the entire depth of the beating heart, and (3) data analysis and reduction protocols for the systematic extraction of quantitative information to describe phenotype and function.

The embryonic vertebrate heart tube is a dynamic suction pump.

The embryonic vertebrate heart begins pumping blood long before the development of discernable chambers and valves. At these early stages, the heart tube has been described as a peristaltic pump. Recent advances in confocal laser scanning microscopy and four-dimensional visualization have warranted another look at early cardiac structure and function.

Four-dimensional cardiac imaging in living embryos via postacquisition synchronization of nongated slice sequences.

Being able to acquire, visualize, and analyze 3D time series (4D data) from living embryos makes it possible to understand complex dynamic movements at early stages of embryonic development. Despite recent technological breakthroughs in 2D dynamic imaging, confocal microscopes remain quite slow at capturing optical sections at successive depths. However, when the studied motion is periodic--such as for a beating heart--a way to circumvent this problem is to acquire, successively, sets of 2D+time slice sequences at increasing depths over at least one time period and later rearrange them to recover a 3D+time sequence.

Intracardiac fluid forces are an essential epigenetic factor for embryonic cardiogenesis.

The pattern of blood flow in the developing heart has long been proposed to play a significant role in cardiac morphogenesis. In response to flow-induced forces, cultured cardiac endothelial cells rearrange their cytoskeletal structure and change their gene expression profiles. To link such in vitro data to the intact heart, we performed quantitative in vivo analyses of intracardiac flow forces in zebrafish embryos.