Abstract: Excitation–contraction coupling is the process by which the cardiomyocyte translates electrical excitation into mechanical contraction. The RyR2 plays a central role in the process. Ca2+-handling and Na+-handling participate the whole process of excitation–contraction coupling. Alterations in Ca2+-handling proteins and intracellular kinases are involved in the pathogenesis of heart failure. Changes in Ca2+-handling often precede the depression of myocardial function. Intracellular Ca2+-handling is closely coupled with intracellular Na+-handling. Intracellular Na+-handling is disturbed with elevated intracellular Na+-concentration and increased late INa. Diastolic Ca2+ can consecutively increase contributing to diastolic dysfunction and heart failure as well as arrhythmias.

Key words: excitation–contraction coupling, calcium/calmodulin-dependent protein kinase II, Ca2+-handling, Na+-handling