Title: Enhanced Ca(2+) release and Na/Ca exchange activity in hypertrophied canine ventricular myocytes: potential link between contractile adaptation and arrhythmogenesis
Authors: Sipido, Karin ×
Volders, P G
de Groot, S H
Verdonck, Alfons
Van de Werf, Frans
Wellens, H J
Vos, M A #
Issue Date: Oct-2000
Publisher: American Heart Association
Series Title: Circulation vol:102 issue:17 pages:2137-44
Abstract: BACKGROUND: Ventricular arrhythmias are a major cause of sudden death in patients with heart failure and hypertrophy. The dog with chronic complete atrioventricular block (CAVB) has biventricular hypertrophy and ventricular arrhythmias and is a useful model to study underlying cellular mechanisms. We investigated whether changes in Ca(2+) homeostasis are part of the contractile adaptation to CAVB and might contribute to arrhythmogenesis. METHODS AND RESUTLS: In enzymatically isolated myocytes, cell shortening, Ca(2+) release from the sarcoplasmic reticulum (SR), and SR Ca(2+) content were enhanced at low stimulation frequencies. Ca(2+) influx through L-type Ca(2+) channels was unchanged, but Ca(2+) influx via the Na/Ca exchanger was increased and contributed to Ca(2+) loading of the SR. Inward Na/Ca exchange currents were also larger. Changes in Ca(2+) fluxes were less pronounced in the right versus left ventricle. CONCLUSIONS: Enhanced Na/Ca exchange activity may improve contractile adaptation to CAVB but at the same time facilitate arrhythmias by (1) increasing the propensity to Ca(2+) overload, (2) providing more inward current leading to (nonhomogeneous) action potential prolongation, and (3) enhancing (arrhythmogenic) currents during spontaneous Ca(2+) release.
ISSN: 0009-7322
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Interdisciplinary Research Facility Life Sciences, Campus Kulak Kortrijk
Experimental Cardiology
Faculty of Medicine - miscellaneous
× corresponding author
# (joint) last author

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