KCNH2 and chronic obstructive pulmonary disease: The genetic or acquired dysfunction of IKr or IKs may cause cardiac arrhythmias due to prolongation of electrocardiogram (ECG) QT interval induced by delayed ventricular repolarization; therefore, blockade of IKr (hERG) and/or IKs is implicated to be a potential risk of cardiac arrhythmia[51, 52].