atrioventricular dissociation

(redirected from AV dissociation)

dissociation

 [dis-so″she-a´shun]
1. the act of separating or state of being separated.
2. the separation of a molecule into fragments produced by the absorption of light or thermal energy or by solvation.
3. segregation of a group of mental processes from the rest of a person's usually integrated functions of consciousness, memory, perception, and sensory and motor behavior, as in the separation of personality and aspects of memory or subpersonalities in the dissociative disorders or in the segregation of an idea or object from its emotional significance, as is sometimes seen in schizophrenia.
atrial dissociation independent beating of the left and right atria, each with normal rhythm or with various combinations of normal rhythm, atrial flutter, or atrial fibrillation.
atrioventricular dissociation a condition in which the atria and the ventricles contract independently of each other, without synchronization of their rhythms.
electromechanical dissociation pulseless electrical activity.
isorhythmic atrioventricular dissociation a cardiac rhythm in which the atria and the ventricles beat independently and at approximately the same rate.

a·tri·o·ven·tric·u·lar dis·so·ci·a·tion (AVD),

, AV dissociation [MIM*209600]
1. any situation in which atria and ventricles are activated and contract independently, as in complete AV block;
2. more specifically, the dissociation between atria and ventricles that results from slowing of the atrial pacemaker or acceleration of the ventricular pacemaker at nearly (although rarely exactly) equal rates, each depolarizing its own chamber, thus interfering with depolarization by the other (interference-dissociation).

atrioventricular dissociation

n.
A condition in which the atria and ventricles contract independently, especially as resulting from the slowing of an atrial pacemaker or the acceleration of a ventricular pacemaker.

atrioventricular dissociation

The independent depolarisation of the atria and ventricles, where atrial rhythm is controlled by one pacemaker and the ventricular rhythm is controlled by another, accompanied by atrioventricular dyssynchrony. Atrioventricular dissociation is not a primary condition in itself, but rather a symptom of an underlying dysrhythmia due to one of a number of causes that prevent the normal transmission of AV impulses:
• Slowing of the dominant pacemaker (usually the sinus node), which allows escape of a subsidiary (latent) pacemaker;
• Acceleration of a latent pacemaker, which wrests control of the ventricles and is accompanied by a pathologically enhanced rate of discharge;
• AV or 3rd-degree block, which prevents normal impulses from a dominant pacemaker from reaching the ventricles, allowing them to beat under the control of the subsidiary pacemaker.

atrioventricular dissociation

AV dissociation Cardiology The independent depolarization of the atria and ventricles, where atrial rhythm is controlled by one pacemaker and the ventricular rhythm is controlled by another, accompanied by a loss of A-V synchrony. See Third-degree block.
References in periodicals archive ?
Holter monitoring identified ventricular tachycardia with RR' morphology in V1 with R> R', 100/min, with AV dissociation (Figure 3, arrows).
Out of these twelve patients nine suffered from severe sinus bradycardia, junctional bradycardia, or complete AV dissociation [11].
Moreover, grade 1 left ventricular diastolic dysfunction, mild pulmonary regurgitation, mild tricuspid regurgitation (TR), mild mitral regurgitation, and low heart rate with AV dissociation were noted during echocardiography.
The physical examination during a tachycardia is most helpful if signs of AV dissociation are present, which strongly suggests VT.
We document a case of AV dissociation and congestive heart failure associated with mitral valve insufficiency in a ring-necked pheasant.
Figure 2: Third degree heart block showing AV dissociation.
DIAGNOSIS: Atrial tachycardia (214/min) with atrioventricular (AV) block and complete AV dissociation from junctional tachycardia (140/min), together with repolarization changes of digitalis, suggest digitalis toxicity.
(20,21) It is typically diagnosed in childhood and usually presents as a narrow QRS tachycardia with AV dissociation, (22) but retrograde conduction to the atrium has also been found.
The forms most commonly found include atrial pacemaker migration; isorrhythmic AV dissociation; nodal rhythm; suprventricular extrasystoles; supraventricular and ventricular paroxysmal tachycardia (1-5).
This lack of synchrony may be due to AV dissociation, retrograde activation of atria or normal activation in the presence of extreme first-degree AV block.
These algorithms logically integrate rate detection with information about conduction patterns, regularity, and AV dissociation. They are designed to maintain high sensitivity for ventricular tachyarrhythmias while improving discrimination for SVTs.
v was given, ECG was done which showed wide QRS complexes >120ms, rate 156/min, AV dissociation, QRS complexes monomorphic.