atrial dissociation n.
Independent beating of the two atria or of parts of the atria.
- Atrial extrasystole
atrial extrasystole atrial extrasystole n. A premature contraction of the heart arising from an ectopic atrial focus.
- Atrial fibrillation
atrial fibrillation 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.