Comparison of antifibrillatory potency of certain antimalarial drugs with quinidine and procaine amide.

The procedure used to assay the potency of antifibrillatory drugs has been described by DiPalma and colleagues. A brief summary will suffice for this report. Cats weighing between 2 and 3 Kg. were anesthetized with intraperitoneal Dial (Ciba). Artificial respiration was maintained at an even level with a suitable pump, and the heart was exposed and suspended in :i pericardinl cradle. Clip electrodes were attached to the right atrium. A current of 600 impulses per minute was supplied by a thyratron stimulator. The current was conducted through a calibrated and variable resistance unit which permitted the determination of the liminal amount of current which would just induce atrial fibrillation. On the average this varied between 2 and S milliamperes. In a typical assay the control fibrillation threshold