Abstract 12899: A Novel Model to Perform Electrophysiological Studies in the Embryonic Mouse Heart
Background: Permanent and conditioned gain-and-loss of function strategies provide an increasing number of mice with interesting cardiac phenotypes. However, a detailed analysis of alterations of cardiac electrophysiology and interpretation of the underlying reasons was hampered so far due to the lack of appropriate methods enabling to study the function of the early embryonic mouse heart.
Methods: Here we provide a novel approach for a detailed study of embryonic murine cardiac electrophysiology. Microelectrode arrays combined with newly developed stimulation electrode allow electrocardiogram (ECG)-like recordings and electrical pacing of atria and ventricles even during the earliest steps of murine heart development, i.e. embryonic day 8.5 (E8.5) post coitum.
Results: We herewith gained insight into physiological paradigms of cardiac development: (i) ECG-like field potential traces with typical P-waves, QRS complexes and T-waves with high temporal resolution were observed even at early steps of murine cardiac differentiation. (ii) In clear contrast to the morphological separation of atria and ventricles that occours around E10.0 post coitum, functional separation was visible around E9.0 by emerging atrial and ventricular FPs with a distinctive ECG-like FP morphology and a fixed atrio-ventricular (AV) conduction time. (iii) Electrical pacing - performed for analysis of the electrophysiological conduction properties - induced significant and reversible prolongation of AV and VA conduction at higher stimulation frequencies. (iv) Moreover, electrical stimulation led to frequency-dependent atrio-ventricular (AV) blocks.
Conclusion: In summary, these electrophysiological studies gained new insight into murine heart development and may be of considerable value for a functional characterization of embryonic cardiac phenotypes.
- © 2010 by American Heart Association, Inc.