TABLE I.

Abbreviations and Definitions

Abbreviation	Definition	Units
SR	Sarcoplasmic reticulum
CaMKII	Ca2+/calmodulin-dependent protein kinase II
RyR	ryanodine receptor
LCC	L-type calcium channel
SERCA	SR Ca2+-ATPase pump
PLB	phospholamban
SERCA/PLB	the SERCA/PLB complex
CSQN	calsequestrin
CICR	Ca2+ induced Ca2+ release process
JSR	junctional SR
NSR	network SR
AP	action potential	mV
APD	AP duration at 90% repolarization	ms
CL	cycle length	ms
FDAR	frequency-dependent acceleration of relaxation
PFFR	positive force-frequency relation
CaMKactive	Fraction of active CaMKII binding sites
CaMK0	Fraction of low affinity calmodulin CaMKII binding sites
IRel	flux through RyR	mmol/L/ms
Itr	Ca2+ translocation flux from NSR to JSR	mmol/L/ms
CTNaCl	Na+ − Cl− cotransporter	mmol/L/ms
CTKCl	K+ − Cl− cotransporter	mmol/L/ms
Idiffusion	Ca2+ translocation flux from subspace to myoplasm	mmol/L/ms
Iup	Ca2+ uptake flux by SERCA pump	mmol/L/ms
Ileak	Ca2+ leak from SR	mmol/L/ms
[Ca2+]JSR	free Ca2+ concentration in JSR	mmol/L
[Ca2+]JSR,t	total Ca2+ concentration in JSR	mmol/L
[Ca2+]NSR	Ca2+ concentration in NSR	mmol/L
$C{a}_{SR}^{2+}$	total Ca2+ content in SR	mmol
INa	fast sodium current	μA/μF
INa,L	Slowly inactivating late Na+ current	μA/μF
ICa(L)	current through LCC	μA/μF
IKr	Rapid delayed rectifier K+ current	μA/μF
IKs	Slow delayed rectifier K+ current,	μA/μF
IK1	Inward rectifier K+ current,	μA/μF
INaCa	current through Na+/Ca2+ exchanger	μA/μF
INaK	current through Na+/K+ pump	μA/μF
Ito1	transient outward K+ current	μA/μF
IK,ATP	ATP dependent K+ current	μA/μF
Ito2	Ca2+ depended transient outward (Cl−) current	μA/μF
ΔCa2+	max(CaT)- min(CaT)	μmol/L
CaT ,[Ca2+]i	free Ca2+ concentration in myoplasm	μmol/L
[Ca2+]ss	free Ca2+ concentration in subspace	μmol/L
$\overline{\mathit{CaT}}$	ratio of max(CaT)/min(CaT)