Fig. 2.

Deteriorations of excitation–contraction coupling in heart failure; arrows indicate Ca²⁺ shifts in systole (left) and diastole (right); diastolic Ca²⁺ leak is highlighted in red; changes in protein function and ion concentrations are indicated by vertical red arrows; ↑ increase; ↓ decrease; L-type L-type Ca²⁺ channel; RyR2 ryanodine receptor type 2; SR sarcoplasmic reticulum; PLB phospholamban; TnI troponin I; NCX Na⁺–Ca²⁺-exchanger; SERCA2a sarcoplasmic endoplasmic reticulum Ca²⁺-ATPase 2a; P phosphate