Low dose of acetylsalicylic acid prolongs refractory periods in normal cat myocardium.

The effect of acetylsalicylic acid (ASA, Aspisol) upon diastolic threshold and refractory period in normal myocardium was investigated in the experiments on cats. It has been found that ASA given in a dose of 7 mg/kg i.v. significantly prolongs refractory period up to 27.7% of initial value throughout 2 h or observation. No significant changes in diastolic threshold were detected. Since the prolongation of refractory period favours stabilisation of cardiac rhythm, this effect of ASA may contribute to antiarrhythmic action of this drug observed earlier by other authors.