hERG blockade can lengthen repolarization
Experimental work has found that ibogaine and its metabolite noribogaine can inhibit the hERG potassium channel. This channel contributes to cardiac repolarization; disruption can be reflected as QT or QTc prolongation on an electrocardiogram.
QT prolongation is important because it can create conditions associated with torsades de pointes, a potentially life-threatening ventricular arrhythmia. An intended microdose does not establish that this pathway is irrelevant.