NDLI: Decay of postextrasystolic potentiation in the left and right ventricles of intact canine hearts

Content Provider	IEEE Xplore Digital Library
Author	Black, A. Ewert, D. Mulligan, L.J.
Copyright Year	2009
Description	Author affiliation: Electrical Engineering Department at North Dakota State University, Fargo, ND 58105 (Ewert, D.) \|\| Therapy Delivery of Medtronic, Inc., Mounds View, MN 55112 (Mulligan, L.J.)
Abstract	Intracellular regulation of myocardial $Ca^{2+}$ has long been of interest to physiologists. The force-interval relationship provides a phenomenological approach that permits insight into aspects of calcium regulation. The response to an extrasystole is a potentiation in contractile force and the recovery in contractile force is described by the recirculation fraction (RF). The RF provides a gross estimation of calcium uptake by sarcoplasmic reticulum (SR), leading to myocardial relaxation. The current study focused on the relationship of right (RV) and left ventricular (LV) RF in canines under several contractile states. Anesthetized canines (n = 5) were catheterized for RV and LV pressure measurements. dP/dtmax for the RV and LV was calculated for three baseline beats, one extrasystole and the first five postextrasystolic beats. The relationship between the LV dP/dtmax and RV dP/dtmax for all of the mentioned beats was then examined. Contractility was increased with calcium chloride and extrasystoles were delivered. Once cardiac function returned to a baseline level, contractility was reduced by increasing the concentration of isoflurane and the evaluation repeated. All ventricular contractions were controlled by RA pacing to maintain intrinsic conduction. A strong linear relationship between RV and LV dP/dtmax (r = 0.94 ± .06) existed for most canine's contractile states. These results build on findings in isolated hearts and demonstrate that biventricular response to extrasystoles and subsequent contractile recovery is both linear and correlated, suggesting that intracellular calcium regulation in a given heart across contractile state is static.
Starting Page	2904
Ending Page	2906
File Size	377542
Page Count	3
File Format	PDF
ISBN	9781424432967
ISSN	1557170X
DOI	10.1109/IEMBS.2009.5334445
Language	English
Publisher	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Publisher Date	2009-09-03
Publisher Place	USA
Access Restriction	Subscribed
Rights Holder	Institute of Electrical and Electronics Engineers, Inc. (IEEE)
Subject Keyword	Radio frequency Calcium Steady-state Strontium Myocardium Heart rate USA Councils Catheterization Pressure measurement Geometry
Content Type	Text
Resource Type	Article
Subject	Signal Processing Biomedical Engineering Health Informatics Computer Vision and Pattern Recognition

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