Pharmacology of new ethylenediamine derivatives (ROM-126, ROM-131, MK-142) with antiarrhythmic action. Part II. Antiarrhythmic properties, the influence on heart and some hemodynamic parameters.

ROM-126, ROM-131, MK-142 prevent arrhythmias: in digoxin-induced arrhythmia MK-142 in a lower dose and ROM-126 in a higher dose are most effective; MK-142 antagonizes most powerfully the aconitine arrhythmia. MK-142, contrary to ROM-126 and ROM-131 weakens also the toxic action of CaCl2 on heart. All tested drugs, however, antagonize adrenaline-induced arrhythmia to a similar degree. MK-142 did not influence the coronary blood flow in guinea pig or rabbit isolated hearts while ROM-126 and ROM-131 increased it. In the experiments performed on dogs "in situ" the decrease in sinus outflow was stated after all the three drugs. Arterio-coronary-oxygen difference did not undergo any significant changes. The calculated values of cardiac muscle oxygen usage showed tendency to decrease. All the three drugs induced transient hypotension, decrease in heart rate and cardiac muscle contractility, increase in outflow index and also, after MK-142, in minute volume.