SCN5A and familial long QT syndrome: It restored the transmural repolarisation gradients to those of normal (WT) hearts.68 Nicorandil is similarly anti‐arrhythmic in clinical LQTS, reducing QT intervals and spatial repolarisation gradients.69, 70, 71 Restitution properties investigated through progressive increases in pacing frequency of murine Scn5a+/∆KPQ hearts showed higher diastolic intervals following action potential recovery, DIcrit, at which instabilities in excitation could potentially result in APD alternans producing re‐entrant substrate, compared to WT.