When this channel's ability to conduct electrical current across the cell membrane is inhibited or compromised, either by application of drugs or by rare mutations in some families,[5] it can result in a potentially fatal disorder called long QT syndrome.

Conversely, genetic mutations that increase the current through these channels can lead to the related inherited heart rhythm disorder short QT syndrome.

[6] A number of clinically successful drugs in the market have had the tendency to inhibit hERG, lengthening the QT and potentially leading to a fatal irregularity of the heartbeat (a ventricular tachyarrhythmia called torsades de pointes).

[7] Although there exist other potential targets for cardiac adverse effects, the vast majority of drugs associated with acquired QT prolongation are known to interact with the hERG potassium channel.

[23] hERG containing channels are blocked by amiodarone, and it does prolong the QT interval, but its multiple other antiarrhythmic effects prevent this from causing torsades de pointes.

When flies with mutations in the Ether-à-go-go gene are anaesthetised with ether, their legs start to shake, like the dancing at the then popular Whisky a Go Go nightclub in West Hollywood, California.