[Effects of practolol on A-V conduction during atrial stimulation in 50 patients with and without coronary heart disease].

Practolol was injected intravenously at 3 dose levels (5, 15 and 25 mg total dose) in patients with ischemic heart disease and in non-cardiac cases. The influence of practolol on the P-Q interval at rest and at paced rates (atrial stimulation) of 110, 125 and 140 beats/min was studied: only the 15 mg dose produced a significant prolongation of the P-Q interval of normal patients at rest and at paced rates. No significant P-Q changes were found in patients with ischemic heart disease at all dose levels. It is concluded that practolol has no measurable direct effect on A-V conduction and that patients with ischemic heart disease are not more sensitive as regards A-V conduction.