Abstract
Introduction: During the initial phase of its pump action, vertebrate embryonic hearts
are seen as valveless tubular pumps. It was traditionally thought that these tubular
hearts generate unidirectional blood flow via peristalsis. Recently, however, the
pumping mechanism of early embryonic hearts has become a matter of dispute.
Uncovering of the pumping mechanism of tubular embryonic hearts requires detailed
information about the hemodynamics as well as morphological dynamics of the pump
action. We have analyzed the morphological dynamics of cardiac pump action in chick
embryos (HH-stage 16) using densitometric analyses of high-speed video recordings
and M-mode optical coherence tomography (OCT) recordings. Materials and Methods:
White leghorn chick embryos (HH-stages 16) were grown in shell-less culture.
Examinations were carried out in an environmental incubator, that provided stable
physiological conditions during examination of the embryos. The high-speed video
camera (120 frames/s) and the probe of the OCT system (4000 A-scans/s, 5.1μm axial
pixel spacing) were integrated into the environmental incubator. Hearts were examined
in frontal views. For this purpose, the embryos were rotated rightward around their
cranio-caudal axis. During examination this position was stabilized by using clips made
of tungsten wire. Results: Utilizing OCT M-modes we have recorded striking differences
in the contraction behavior (e.g. contraction speed, duration of systolic occlusion of
heart lumen) of the embryonic heart segments (common atrium, AV-canal, embryonic
ventricles, outflow tract). Video densitometric M-mode curves show remarkable
similarities to OCT M-mode recordings. OCT M-mode recordings can only be taken at
one site at a time whereas video densitometry allows simultaneous recordings at any
site. Moreover, we show, for the first time, the pump action of tubular embryonic chick
hearts in frontal views, which provide a much better understanding of early cardiac
pump action than the traditional right or left lateral views. Summary: OCT M-mode
recordings and video densitometric analyses show striking differences in contraction
behavior of different heart segments of the tubular embryonic heart. These findings are
important for the understanding of the pumping mechanism of the developing
valveless embryonic heart.
Original language | English |
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Publication date | 2011 |
Publication status | Published - 2011 |
Event | Annual Meeting of German Cardiac Society 2011 - Mannheim, Germany Duration: 27 Mar 2011 → 30 Mar 2011 Conference number: 77 |
Conference
Conference | Annual Meeting of German Cardiac Society 2011 |
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Number | 77 |
Country/Territory | Germany |
City | Mannheim |
Period | 27/03/2011 → 30/03/2011 |