“…Atrioventricular block although rare, is the most frequent serious adverse event related to diltiazem therapy and may be exacerbated by coadministration of beta-adrenoceptor antagonists, especially in the elderly (Markham and Brogden, 1993;Chaffman and Brogden, 1985). In line with this concept, SZV-270 (Figure 3), a novel agent was synthesized by our collaborators from two well-known pure Class I/B and III antiarrhythmic agents, mexiletine and D-Sotalol, respectively.…”