Biomaterial Database

Is class III antiarrhythmic activity important? 1990

B N Singh

VA Medical Center WLA, CA 90073.

The beginning of thought about a discrete Class III antiarrhythmic action stemmed from the observation that sotalol produced a very marked increase in the time course of repolarization with little or no change in conduction velocity in cardiac muscle. It is known that in patients with hypothyroidism or hypocalcemia, both of which are associated with a marked lengthening of the cardiac action potential, arrhythmias are exceedingly rare. The acetyl metabolite of procainamide also produces, as its sole action, a marked increase in the action-potential duration, and it has antiarrhythmic activity. It is clear that lengthening the action-potential duration is antiarrhythmic. Sotalol is a unique beta blocker in not only antagonizing sympathetic stimulation competitively, but also in exerting a potent antiarrhythmic effect by prolonging repolarization. Because of the augmented tension that is associated with the increase in action-potential duration, sotalol produces a less negative inotropic effect than that seen with other beta blockers. Sotalol is a potent broad-spectrum antiarrhythmic agent because of its Class III properties, resulting from an increase in the length of cardiac repolarization, a property that is modulated by its beta-adrenergic blocking actions.

UI	MeSH Term	Description	Entries
D007037	Hypothyroidism	A syndrome that results from abnormally low secretion of THYROID HORMONES from the THYROID GLAND, leading to a decrease in BASAL METABOLIC RATE. In its most severe form, there is accumulation of MUCOPOLYSACCHARIDES in the SKIN and EDEMA, known as MYXEDEMA. It may be primary or secondary due to other pituitary disease, or hypothalamic dysfunction.	Central Hypothyroidism,Primary Hypothyroidism,Secondary Hypothyroidism,TSH Deficiency,Thyroid-Stimulating Hormone Deficiency,Central Hypothyroidisms,Deficiency, TSH,Deficiency, Thyroid-Stimulating Hormone,Hormone Deficiency, Thyroid-Stimulating,Hypothyroidism, Central,Hypothyroidism, Primary,Hypothyroidism, Secondary,Hypothyroidisms,Primary Hypothyroidisms,Secondary Hypothyroidisms,TSH Deficiencies,Thyroid Stimulating Hormone Deficiency,Thyroid-Stimulating Hormone Deficiencies
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001145	Arrhythmias, Cardiac	Any disturbances of the normal rhythmic beating of the heart or MYOCARDIAL CONTRACTION. Cardiac arrhythmias can be classified by the abnormalities in HEART RATE, disorders of electrical impulse generation, or impulse conduction.	Arrhythmia,Arrythmia,Cardiac Arrhythmia,Cardiac Arrhythmias,Cardiac Dysrhythmia,Arrhythmia, Cardiac,Dysrhythmia, Cardiac
D013015	Sotalol	An adrenergic beta-antagonist that is used in the treatment of life-threatening arrhythmias.	Darob,MJ-1999,Sotalol Hydrochloride,Sotalol Monohydrochloride,MJ 1999,MJ1999
D066298	In Vitro Techniques	Methods to study reactions or processes taking place in an artificial environment outside the living organism.	In Vitro Test,In Vitro Testing,In Vitro Tests,In Vitro as Topic,In Vitro,In Vitro Technique,In Vitro Testings,Technique, In Vitro,Techniques, In Vitro,Test, In Vitro,Testing, In Vitro,Testings, In Vitro,Tests, In Vitro,Vitro Testing, In