At the whole heart level, we have previously shown that nifedipine (1 μm) eliminated episodes of VT in genetically modified mouse models of LQT3 and LQT5 generated through targeted disruption of SCN5a and KCNE1, respectively (Thomas et al. 2007a,b) through blockade of the LTCC. This evidence concerns the gene SCN5A and long QT syndrome 3.