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 (AV) dissociation

a breakdown in the normal conduction of excitation through the heart, allowing the atria and ventricles to beat independently under the control of their own pacemakers.

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.

dissociation

the act of separating or the state of being separated.

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
independent pacemakers in the atria and ventricles.
dissociation constant
the tendency of a solute to dissociate in solution.
hepatocyte dissociation
hepatocytes becomes detached from their neighboring cells, either generally or locally; a feature of death of the patient.
References in periodicals archive ?
The AV dissociation in the pheasant was determined incidentally during a study to evaluate the electrocardiograms (ECGs) in 24 pheasants obtained from the Gelemen Pheasant Production Station, Samsun, Turkey.
We document a case of AV dissociation and congestive heart failure associated with mitral valve insufficiency in a ring-necked pheasant.
The AV dissociation is separated into 2 subtypes: 1) the atria and ventricles beat independent of each other under the control of separate pacemaker foci, and 2) impulses from the sinoatrial node can occasionally be conducted to the ventricle during AV dissociation, causing ventricular capture and ventricular fusion complexes, termed as complete and incomplete AV dissociation, respectively.
Although it has been reported that the overall incidence of AV dissociation is somewhere between approximately 0.
This pheasant showed complete AV dissociation based on ECG findings.
From the results of the histopathologic findings and the ECG in this case, we concluded that the AV dissociation documented in this pheasant may have originated from ventricular hypertrophy due to mitral valve insufficiency.
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.
This is not synonymous with AV dissociation, which simply means that the atria and the ventricles are being driven by different pacemaking foci.
AV dissociation (present in the majority of VT)--the absence of VA dissociation is not helpful, because VT may happen with 1:1 VA conduction.
These algorithms logically integrate rate detection with information about conduction patterns, regularity, and AV dissociation.
Case 1 was a 57-year-old white male with a history of severe chronic obstructive pulmonary disease who was transferred to our institution with acute coronary syndrome, having AV dissociation with widened QRS complexes and elevated cardiac enzymes.
Another common issue regarding catheter stability is the catheter dislodgement due to the AV dissociation occurring after the elimination of AP conduction when RF ablation is being performed during ventricular pacing in some unstable locations (6).