= v 0 x ∈ ∂ h . =v_\quad \mathbf \in \partial \mathbb .} instead, if the heart is considered as isolated, which means that no myocardial region is presented, a possible boundary condition for the extracellular problem is ( σ i ∇ v ) ⋅ n = − ( ( σ i + σ e ) ∇ v e ) ⋅ n x ∈ ∂ h . _\nabla v\right)\cdot \mathbf =-\left((\mathbf _+\mathbf _)\nabla v_\right)\cdot \mathbf \quad \mathbf \in \partial \mathbb .} reduction to monodomain model by assuming equal anisotropy ratios for the intra- and extracellular domains, i.e. σ i = λ σ e _=\lambda \mathbf _ for some scalar λ , the model can be reduced to one single equation, called monodomain equation ∇ ⋅ ( σ ∇ v ) = χ ( c m ∂ v ∂ t + i i o n ) − i s \nabla v)=\chi \left(c_+i_ }\right)-i_ where the only variable is now the transmembrane potential, and the conductivity tensor σ } is a combination of σ i _ and σ e . _.} formulation with boundary conditions in an isolated domain if the heart is considered as an isolated tissue, which means that no current can flow outside of it, the final formulation with boundary conditions reads { ∇ ⋅ ( σ i ∇ v ) + ∇ ⋅ ( σ i ∇ v e ) = χ ( c m ∂ v ∂ t + i i o n ) − i s 1 x ∈ h ∇ ⋅ ( ( σ i + σ e ) ∇ v e ) = − ∇ ⋅ ( σ i ∇ v ) + i s 2 x ∈ h σ i ( ∇ v + ∇ v e ) ⋅ n = 0 x ∈ ∂ h [ σ i ( ∇ v + ∇ v e ) + σ e ∇ v e ] ⋅ n = 0 x ∈ ∂ h \nabla \cdot \left(\mathbf _\nabla v\right)+\nabla \cdot \left(\mathbf _\nabla v_\right)=\chi \left(c_+i_ }\right)-i_&\mathbf \in \mathbb \\\nabla \cdot \left(\left(\mathbf _+\mathbf _\right)\nabla v_\right)=-\nabla \cdot \left(\mathbf _\nabla v\right)+i_&\mathbf \in \mathbb \\\mathbf _(\nabla v+\nabla v_)\cdot \mathbf =0&\mathbf \in \partial \mathbb \\\left\cdot \mathbf =0&\mathbf \in \partial \mathbb \end numerical solution there are various possible techniques to solve the bidomain equations. between them, one can find finite difference schemes, finite element schemes and also finite volume schemes. special considerations can be made for the numerical solution of these equations, due to the high time and space resolution needed for numerical convergence.