Accordingly, Ca2+ overload-related arrhythmias could be caused by Na+-induced Ca2+ overload following Na/K ATPase blockade, or may be due to increased sympathetic tone, hypokalaemia, etc. In this part of the review, the effects of selective NCX inhibition on elementary arrhythmogenic events are summarized. The gene discussed is TLX2; the disease is cardiac arrhythmia.