VA conduction

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VA conduction (ventriculoatrial conduction) refers to the electrical conduction from the ventricles of the heart back to the atria. This phenomenon is significant in the context of certain arrhythmias and can be observed in conditions such as atrioventricular reentrant tachycardia (AVRT) and atrioventricular nodal reentrant tachycardia (AVNRT).

Mechanism

VA conduction occurs when an electrical impulse originates in the ventricles and travels retrogradely through the atrioventricular node (AV node) or an accessory pathway to the atria. This can result in the atria being activated after the ventricles, which is the reverse of the normal conduction sequence. The presence of VA conduction can be indicative of an underlying reentrant circuit, which is a common mechanism in certain types of supraventricular tachycardias.

Clinical Significance

VA conduction is often assessed during electrophysiological studies to diagnose and characterize arrhythmias. It can help in identifying the presence of accessory pathways, which are abnormal electrical connections between the atria and ventricles that bypass the AV node. These pathways can lead to conditions such as Wolff-Parkinson-White syndrome (WPW).

Diagnosis

The diagnosis of VA conduction typically involves the use of ECG and intracardiac electrograms. During an electrophysiological study, programmed electrical stimulation of the heart can be used to induce and analyze VA conduction. The presence of retrograde P waves on the ECG following a ventricular beat is indicative of VA conduction.

Treatment

The treatment of conditions associated with VA conduction depends on the underlying arrhythmia. Options may include antiarrhythmic medications, catheter ablation, and in some cases, pacemaker implantation. Catheter ablation is a common and effective treatment for eliminating accessory pathways and preventing reentrant tachycardias.

See Also

• Atrioventricular reentrant tachycardia
• Atrioventricular nodal reentrant tachycardia
• Wolff-Parkinson-White syndrome
• Electrophysiology study
• Electrocardiogram