Electrophysiologic properties of intravenous Tenormine in man.

The acute electrophysiologic effects of intravenous Tenormine (0.1 mg/kg body weight), a new cardioselective beta-adrenoreceptor blocking drug, were studied in 18 subjects with estimated normal impulse formation and conduction. The most significant (P less than 0.01) effects were sinus cycle lengthening, depression of intranodal conduction and prolongation of AV node refractory periods. Sinus node recovery time, sinoatrial conduction time and atrial refractory periods were only slightly prolonged (P less than 0.05). Intraatrial conduction and infra-His conduction were unchanged. These properties are compared with those of the most commonly employed beta-blocking agents. The clinical implications are discussed.