SCN5A and long QT syndrome 3: Ranolazine is a more selective SCN5A blocker (Belardinelli et al., 2006; Zaza et al., 2008) and has been shown to attenuate action potential duration and reduce or prevent intracellular calcium overload in LQT3 models (Wu et al., 2004; Lindegger et al., 2009).