Regional dispersion of L-type calcium current in ventricular myocytes of German shepherd dogs with lethal cardiac arrhythmias
L Protas, EA Sosunov, EP Anyukhovsky, NS Moïse… - Heart Rhythm, 2005 - Elsevier
L Protas, EA Sosunov, EP Anyukhovsky, NS Moïse, MR Rosen, RB Robinson
Heart Rhythm, 2005•ElsevierOBJECTIVES: The purpose of this study was to determine if regional differences in L-type
Ca2+ current (ICa, L) are altered in a German shepherd model of sudden death.
BACKGROUND: German shepherd dogs with inherited sudden cardiac death have reduced
sympathetic innervation in the anteroseptal left ventricle that may contribute to arrhythmias in
afflicted animals compared to control unafflicted animals. Differences in a number of
repolarizing K+ currents have been identified in this model, but ICa, L has not been studied …
Ca2+ current (ICa, L) are altered in a German shepherd model of sudden death.
BACKGROUND: German shepherd dogs with inherited sudden cardiac death have reduced
sympathetic innervation in the anteroseptal left ventricle that may contribute to arrhythmias in
afflicted animals compared to control unafflicted animals. Differences in a number of
repolarizing K+ currents have been identified in this model, but ICa, L has not been studied …
OBJECTIVES
The purpose of this study was to determine if regional differences in L-type Ca2+ current (ICa,L) are altered in a German shepherd model of sudden death.
BACKGROUND
German shepherd dogs with inherited sudden cardiac death have reduced sympathetic innervation in the anteroseptal left ventricle that may contribute to arrhythmias in afflicted animals compared to control unafflicted animals. Differences in a number of repolarizing K+ currents have been identified in this model, but ICa,L has not been studied.
METHODS
We measured action potentials in intact tissue and ICa,L in isolated myocytes from anteroseptal and anterobasal left ventricle.
RESULTS
Action potential plateau level and ICa,L density were significantly lower in unafflicted anteroseptal than in afflicted anteroseptal, afflicted anterobasal, or unafflicted anterobasal. Isoproterenol increased ICa,L density more in the unafflicted anteroseptal group than in the other groups.
CONCLUSIONS
Differences in ICa,L between afflicted and control animals, combined with our earlier finding of regional reductions in IKr, provide a likely substrate for the occurrence of pause-dependent arrhythmias in afflicted animals and for the T-wave abnormalities characterizing them.
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