[Bepridil and bundle of His block. Apropos of a case].

The first case of atrioventricular block located in His bundle observed during oral treatment with bepridil is reported; the block subsided when the drug was discontinued and reappeared when it was reintroduced. Electrophysiological studies performed with bepridil have shown that, as could be foreseen from its beneficial or undesirable effects, this calcium antagonist has some properties of Vaughan Williams' class I antiarrhythmic agents and alters subnodal conduction. Clinical studies indicate that in therapeutic doses this alteration has little or no significance, but it may reach clinical expression when latent of patient pre-existing disorders of conduction within or below His bundle are present.