TLX2 and heart failure: Heart failure is associated with impaired Ca2+ and Na+ handling in failing cardiac myocytes that involves NHE1 and Na+/Ca2+ exchanger (NCX) that are linked to the Na/K-ATPase (Armoundas et al. 2003; Baartscheer et al. 2003a, b, 2005; Bers and Despa 2006; Müller-Ehmsen et al. 2003; Swift et al. 2008).