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Fig. 1 | Journal of Congenital Cardiology

Fig. 1

From: Functional evaluation of gene mutations in Long QT Syndrome: strength of evidence from in vitro assays for deciphering variants of uncertain significance

Fig. 1

Schematic diagram showing how ventricular repolarisation is prolonged and underlying ionic currents are altered by LQT1-LQT3 causing variants. Illustration of the effect of LQTS variants on the human ventricular action potential (AP) and the corresponding changes in the underlying currents. Upper panel: The ventricular AP is prolonged in congenital LQTS (types 1–3) (indicated by grey line) due to either an inappropriate gain of function (GOF) in late sodium current (INa,Late) or a loss of function (LOF) in the slowly (IKs) or rapidly (IKr) activating delayed rectifier potassium currents. Lower panel: Effect of LQTS causing variants in SCN5A, KCNH2 (hERG) or KCNQ1 on the magnitude and temporal profile of the sodium current (INa) or potassium currents (IKr or IKs) respectively. The normal current profiles are shown in black and the currents produced in the presence of LQTS causing variants are displayed in grey. The relative contributions of each current are not drawn to scale

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Journal of Congenital Cardiology

ISSN: 2056-7251

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