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Tachycardia: Difference between revisions
→AV Re-entry Tachycardia (AVRT)
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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 excites 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 a widened QRS complex >120ms due to slurring of the QRS complex (delta wave). This is also called Wolf-Parkison-White symptom and can occur intermittently. 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. | If an accessory bundle excites 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 a widened QRS complex >120ms due to slurring of the QRS complex (delta wave). This is also called Wolf-Parkison-White symptom and can occur intermittently. 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 called a concealed bundle. Patients can be asymptomatic if they only have pre-exitation and this ECG pattern is commonly an incidental finding. When an arrhythmia develops using the accessory bundle, two types of AVRT can develop depending on the conduction characteristics of the 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. | ||
====Management:==== | ====Management:==== | ||
Anti-arrhythmic drugs | The circuit of the arrhythmia uses the AV node, therefore vagal manoeuvres are able to terminate the AVRT. Anti-arrhythmic drugs can be usueful to prevent paroxysms of arrhythmia, but drugs like digitalis and calcium antagonist should be avoided. Catheter ablation can target the accessory pathway and destroy the bundle. The success of the procedure is dependent on the location of the bundle as not all anatomical positions are easily targeted with ablation. It is controversial if patients with an asymptomatic WPW ECG pattern should have an ablation. The characteristics of the bundle and the life-style\proffession of the patient should guide treatment in these cases. | ||
=Ventricular tachycardia= | =Ventricular tachycardia= | ||