atrial fibrillation n.
Fibrillation in which the normal rhythmical contractions of the cardiac atria are replaced by rapid irregular twitchings of the muscular wall that cause the ventricles to respond irregularly. Also called auricular fibrillation.
- Atrial flutter
atrial flutter atrial flutter n. Rapid regular atrial contractions occurring usually at rates between 250 and 400 per minute and often producing saw-tooth waves in an electrocardiogram. Also called auricular flutter.
- Atrial fusion beat
atrial fusion beat atrial fusion beat n. A pulsation occurring when the atria of the heart are activated partly by a sinus impulse and partly by a retrograde impulse from the atrioventricular node or ventricle.
- Atrial natriuretic factor
any of several peptide hormones that are released by the atria of the heart in response to an abnormal increase in blood volume and that modulate blood pressure and the excretion of sodium, potassium, and water. Abbreviation: ANF. atrial natriuretic factor n. A peptide hormone released from cardiac atrial tissue that causes increased elimination of […]
- Atrial septal defect
atrial septal defect atrial septal defect n. A defect in the interatrial septum of the heart, due to failure of the embryonic foramen to close normally.