1. Clinical implications of differences in pharmacodynamic action of polar and nonpolar cardiac glycosides
- Author
-
Thomas M. Runge
- Subjects
Inotrope ,Atropine ,medicine.medical_specialty ,Digoxin ,Digitoxin ,Vomiting ,Sinus bradycardia ,Ouabain ,Cardiac Glycosides ,Internal medicine ,Atrial Fibrillation ,medicine ,Bradycardia ,Animals ,Humans ,Arrhythmia, Sinus ,cardiovascular diseases ,Sympathomimetics ,Tachycardia, Paroxysmal ,Sinoatrial Node ,business.industry ,Atrial fibrillation ,Nausea ,medicine.disease ,Autonomic Agents ,Myocardial Contraction ,Stimulation, Chemical ,Anorexia ,Heart Arrest ,Heart Block ,Atrial Flutter ,Parasympathomimetics ,Anesthesia ,cardiovascular system ,Cardiology ,medicine.symptom ,Cardiology and Cardiovascular Medicine ,business ,Atrioventricular block ,Atrial flutter ,medicine.drug - Abstract
Summary The principal effects of cardiac glycosides probably can be classified as parasympathomimetic or sympathomimetic. Data from animals and from man suggest that polar cardiac glycosides, such as ouabain and digoxin, possess greater parasympathomimetic (vagal) cardiac effect for a given amount of sympathomimetic (positive inotropic) cardiac effect than do less polar cardiac glycosides, such as digitoxin. Polar glycosides therefore offer some advantage in uncomplicated paroxysmal atrial tachycardia and in uncomplicated atrial flutter and atrial fibrillation when the principal desired effect is reduction in the number of atrial impulses reaching the ventricles or conversion to normal sinus rhythm. Non-polar glycosides offer an advantage when positive inotropicity is desired but when there is some degree of atrioventricular block or when inappropriate sinus bradycardia or anorexia, nausea, or vomiting are present. Ectopic impulse formation when due to cardiac glycosides is a toxic manifestation of excessive sympathomimetic effect, but is aggravated by vagal-induced sinus bradycardia, so that both parasympathomimetic and sympathomimetic capability of cardiac glycosides must be considered when dealing with myocardial electrical instability.
- Published
- 1977