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Tachycardia: Difference between revisions
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===AV Re-entry Tachycardia (AVRT)=== | ===AV Re-entry Tachycardia (AVRT)=== | ||
====Pathophysiology:==== | ====Pathophysiology:==== | ||
AVRT are tachycardias with a re-entry circuit compromising the entire heart. Atria, AV-node, ventricle and an extra bundle are an essential part of this circuit. The pre-requisite of an AVRT is the existence of an extra bundle between the atria and ventricle. This bundle can bypass the AV-node. | AVRT are tachycardias with a re-entry circuit compromising the entire heart. Atria, AV-node, ventricle and an extra bundle are an essential part of this circuit. The pre-requisite of an AVRT is the existence of an extra bundle between the atria and ventricle. This bundle can bypass the AV-node and connect to ventricular myocardium or one of the fascicles. The conduction direction of these bundles can be anterograde (atrium-ventricle), retrograde (ventricle-atrium) or bidirectional. | ||
The following bundles exist: | The following bundles exist: | ||
* Bundle of Kent: A connection between atria and ventricles most often located on the lateral side of the atria\ventricles. | * Bundle of Kent: A connection between atria and ventricles most often located on the lateral side of the atria\ventricles. | ||
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* Antidrome AV re-entry tachycardia: The impulse travels antrograde through the accessory bundle and activates the ventricles. The impulse returns through the normal conduction system to the atria. | * Antidrome AV re-entry tachycardia: The impulse travels antrograde through the accessory bundle and activates the ventricles. The impulse returns through the normal conduction system to the atria. | ||
====Clinical diagnosis:==== | ====Clinical diagnosis:==== | ||
If an accessory bundle exites the ventricle earlier than normal AV-conduction can activate the ventricles, pre-exitation is visible on the ECG. This is a can be visible on the ECG by a shortned PQ interval and slurring of the QRS complex. This is also called Wolf-Parkison-White symptom. If a patient has pre-exitation and traces of a AVRT the combination of these two is called the Wolf-Parkinson-White syndrome. Some patient have an AVRT, but no traces of pre-exitation. The bundle is then a concealed bundle. | |||
* Orthodrome AV re-entry tachycardia: There is a P-wave (other morphology than sinus rhythm) followed by small QRS-complex | * Orthodrome AV re-entry tachycardia: There is a P-wave (other morphology than sinus rhythm) followed by small QRS-complex | ||
* Antidrome AV re-entry tachycardia: The tachycardia resembles a broad-complex tachycardia and is follow by a retrograde P-wave originating from the AV-node. | * Antidrome AV re-entry tachycardia: The tachycardia resembles a broad-complex tachycardia and is follow by a retrograde P-wave originating from the AV-node. | ||