sinus bradycardia

sinus bradycardia,

beating of the sinus node at a rate below 60/min.

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bradycardia [brad″e-kahr´de-ah]

slowness of the heartbeat, so that the pulse rate is less than 60 per minute. This can occur in normal persons, particularly during sleep; trained athletes also usually have slow pulse and heart rates. adj., adj bradycar´diac.

fetal bradycardia a fetal heart rate of less than 120 beats per minute, generally associated with hypoxia; it is usually due to placental insufficiency; it may also result from transfer of local anesthetics or beta-adrenergic blocking agents, and rarely to heart block associated with congenital heart disease or maternal collagen vascular disease.

nodal bradycardia bradycardia in which the stimulus of the heart's contraction arises in the atrioventricular node or common bundle.

sinoatrial bradycardia (sinus bradycardia) a slow sinus rhythm, with a heart rate of less than 60 beats per minute in an adult; it is common in young adults and in athletes but is also a manifestation of some disorders.

bradycardia-tachycardia syndrome any cardiac dysrhythmia characterized by alternating slow and fast heart rates, often resulting in hemodynamic compromise. See also sick sinus syndrome.

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bradycardia

slowness of the heartbeat, in dogs and cats to less than 60 beats per minute.

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sinus bradycardia

a slow sinus rhythm, characterized by normal electrocardiographic complexes in a normal rhythm or a sinus arrhythmia. A normal finding, most commonly seen in large breeds of dogs or athletic animals.

Sinus bradycardia in a dog. By permission from Ettinger SJ, Feldman E, Textbook of Veterinary Internal Medicine, Saunders, 2004

bradycardia-tachycardia syndrome

see sick sinus syndrome.

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sinus bradycardia

Cardiology Sinus-node dysfunction–sick sinus syndrome characterized by a normal P-wave axis of < 60 beats/min EKG Every P wave is followed QRS complexes , or at < 50 beats/min. See Sick sinus syndrome. Cf Sinus tachycardia.