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AV dissociation: Difference between revisions
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A rare presentation of AV dissociation is called isorhythmic A-V dissociation. The P waves and QRS complexes in this type of arrhythmia have a 1:1 relation. However the intervals are such short that this 1:1 relationship cannot be the result of normal AV conduction. Two forms of isorhythmic A-V dissociation can be distinguished<cite>AV</cite>: | A rare presentation of AV dissociation is called isorhythmic A-V dissociation. The P waves and QRS complexes in this type of arrhythmia have a 1:1 relation. However the intervals are such short that this 1:1 relationship cannot be the result of normal AV conduction. Two forms of isorhythmic A-V dissociation can be distinguished<cite>AV</cite>: | ||
* Pattern I: the P wave fluctuates cyclically back and forth across the QRS complex. Sinus node discharge in this form is influenced by a biological feedback mechanism through the baroreceptor reflex, based on stroke volume and blood pressure. | * Pattern I: the P wave fluctuates cyclically back and forth across the QRS complex. Sinus node discharge in this form is influenced by a biological feedback mechanism through the baroreceptor reflex, based on stroke volume and blood pressure. | ||
* Pattern II, the P wave is in a fairly constant position relative to the QRS complex. It is usually coincides with the QRS complex or appears on the ST segment or first half of the T wave. The mechanism producing synchronization in pattern II type of isorhythmic dissociation | * Pattern II, the P wave is in a fairly constant position relative to the QRS complex. It is usually coincides with the QRS complex or appears on the ST segment or first half of the T wave. The mechanism producing synchronization in pattern II type of isorhythmic dissociation is unclear. | ||
==References== | ==References== | ||