“…Nattel, 1991;Rosen et al, 1991). Although its ability to block sodium channels (class I antiarrhythmic actions) has been described in some detail as a use-dependent inhibition (Hille, 1977;Hondeghem & Katzung, 1977;Clarkson & Hondeghem, 1984), the action potential broadening, or class III actions of quinidine are less well understood (Singh & Nadamane, 1985;Hondeghem & Snyders, 1990;Colatsky et al, 1990;Lynch et al, 1992). Part of the reason for this is that in mammalian heart there is a relatively large number of quite diverse potassium (K+) currents (Colatsky et al, 1990;Baumgarten & Fozzard, 1991;Gintant et al, 1991).…”