sinoatrial heart block

sinoatrial heart block

A partial or complete heart block characterized by interference in the passage of impulses from the sinoatrial node.

Synonym: sinoatrial block See: sick sinus syndrome

See also: heart block

heart block

impairment of conduction in heart excitation; often applied specifically to atrioventricular heart block.

When isolated impulses from the atria fail to reach the ventricles, heartbeats are missed and the block is called incomplete. When no impulses reach the ventricles from the atria the heart block is complete, with the result that the atria and the ventricles beat at separate rates. In this case the beats remain regular but the rate of the ventricular beats is greatly slowed down.

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atrioventricular (A-V) heart block

a form in which the blocking is at the atrioventricular junction. It is first degree when A-V conduction time is prolonged; second degree (partial heart block) when some but not all atrial impulses reach the ventricle; third degree (complete heart block) when no atrial impulses at all reach the ventricle, and the atria and ventricles act independently of each other.

bundle-branch heart block

a form in which one ventricle is excited before the other because of absence of conduction in one of the branches of the bundle of His.

complete heart block

see atrioventricular heart block (above).

fascicular heart block

one originating on one of the two divisions of the left bundle branch. See also hemiblock.

interventricular heart block

bundle-branch heart block.

Mobitz heart block b's

variations of second-degree heart blocks. See also wenckebach's phenomenon.

sinoatrial heart block

partial or complete impairment of conduction from the sinoatrial node to the atria, resulting in delay or absence of an atrial beat.