sinus bradycardia


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 insufficiency" >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.

si·nus bra·dy·car·di·a

bradycardia originating in the normal sinus pacemaker.

sinus bradycardia

A heart rhythm caused by sinus-node dysfunction (sick sinus syndrome), which is characterised by a rhythm of less than 60 beats/minute.
Clinical findings
Lightheadedness, dizziness, hypotension and syncope.
Aetiology
Vagal hypertonicity, hypothermia, hypothyroidism, SA node disease, drugs (e.g., digitalis, beta blockers, calcium channel blockers), viral myocarditis or bacterial endocarditis.
EKG
Normal P waves, P-R interval of 0.12–0.20 seconds, QRS complex < 0.12 seconds.

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.

si·nus bra·dy·car·di·a

(sī'nŭs brad'ē-kahr'dē-ă) A heart rate less than 60 beats per minute with a normal rhythm.

sinus bradycardia

A slow, regular, heart rate resulting from a low rate of pacing by the SINOATRIAL NODE. The heart rate is less than 60 beats per minute. Sinus bradycardia is a normal, healthy feature of high physical fitness but may also occur in conditions such as HYPOTHYROIDISM in which the metabolic rate is reduced. It may also be caused by beta-blockers and other drugs.