Andrew McCulloch | Jeffrey Omens
Name: Adam T. Wright
Email: atwright @ ucsd.edu
Grad Year: 2008
Introduction: Abnormal myocardial mechanics have been associated with an increased incidence of cardiac arrhythmias and sudden cardiac death. Change in mechanical load on the myocardium has been shown to alter cardiac electrophysiology in an arrhythmogenic fashion, a phenomenon termed "mechano-electric feedback". The effect of myocardial stretch on action potential conduction was studied in the isolated murine heart subject to volume loading.
Methods: Murine hearts were isolated and maintained by Langendorff perfusion. A fluid filled balloon was inserted into the left ventricle and the myocardium was stretched by inflating the balloon. A voltage-sensitive fluorescent dye is loaded through the perfusion line. Fluorescence images of the ventricular epicardial emission were acquired at high spatial and temporal resolution during ventricular pacing in the loaded and unloaded states. Images were analyzed using custom signal processing algorithms to produce optical action potentials on the ventricular epicardium.
Results and Discussion: Volume loading of the ventricle results in slowed action potential conduction through the myocardium, presenting a pro-arrhythmic substrate. Previous studies from our group indicate that the slowing of conduction in the volume loaded rabbit heart is associated with changes in passive myocardial electrical properties. Application of these methods in the murine heart provides an opportunity to take advantage of transgenic mouse models to determine the underlying cellular and tissue mechanisms behind these changes in action potential conduction.
« Back to Posters or Search Results