Novel heterocyclic dihydropyrimidine compounds useful as inhibitors of
potassium channel function (especially inhibitors of the K.sub.v1
subfamily of voltage gated K.sup.+ channels, especially inhibitors
K.sub.v1.5 which has been linked to the ultra-rapidly activating delayed
rectifier, which have the structure stereoisomers including enantiomers
thereof and diastereomers thereof, or a pharmaceutically acceptable salt
thereof, wherein Q is alkyl, substituted alkyl, cycloalkyl, substituted
cycloalkyl, cycloheteroalkyl, substituted cycloheteroalkyl or which is
aryl, substituted aryl, heteroaryl or substituted heteroaryl; R.sup.3
is wherein R.sup.1, R.sup.2, R.sup.4, R.sup.5, R.sup.6, R.sup.7,
R.sup.8, R.sup.9 and R.sup.10 are defined herein.
Methods of using such compounds in the prevention and treatment of
arrhythmia and I.sub.Kur-associated conditions, and pharmaceutical
compositions containing such compounds are also provided.