Details

Autor(en) / Beteiligte

• Wright, Adam Thomas
• Omens, Jeffrey H
• McCulloch, Andrew D

Titel

Ventricular epicardial conduction slowing in the pressure loaded isolated murine heart

Ist Teil von

• The FASEB journal, 2008-03, Vol.22 (S1)

Erscheinungsjahr

2008

Quelle

Wiley Online Library All Journals

Beschreibungen/Notizen

• Abstract only The mechanisms by which mechanical stimuli alter the cardiac action potential and its propagation (mechanoelectric feedback, MEF) remain poorly understood. Previously, we reported that epicardial conduction velocity (CV) slows during ventricular filling in the isolated rabbit heart in the presence of 2,3‐butanedione monoxime (BDM), an electromechanical decoupler. This has not been reported in other species. Here we use optical mapping of the left ventricular (LV) epicardial surface of isolated beating murine hearts loaded with the voltage sensitive dye, di‐4‐ANNEPS to assess changes in action potential propagation at LV end diastolic pressures of 0 and 30 mmHg. In preliminary studies in the absence of BDM, pressure load resulted in a reversible 10–20% decrease in CV in the directions of fastest (CVmax) and slowest (CVmin) propagation during epicardial pacing (CVmax and CVmin dropped from 480 ± 2 and 208 ± 16 mm/s in the unloaded state to 432 ± 26 and 165 ± 5 mm/s in the loaded state). This drop in CV results in a phenotype promoting reentrant arrhythmias in the loaded state. This experimental design provides a means of studying MEF under physiological conditions and will be used to assess the contributions of stretch activated channels and passive electrical tissue properties to this observed slowing of conduction. This research has been funded by the National Science Foundation and the National Institutes of Health.