Concealed conduction

Concealed Conduction

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Diagram illustrating concealed conduction in the heart.

Concealed conduction is a phenomenon in cardiac electrophysiology where an impulse is transmitted through the heart's conduction system without producing a visible effect on the electrocardiogram (ECG). This occurs when the impulse is not strong enough to depolarize the myocardium but can still influence subsequent impulses.

Mechanism

Concealed conduction typically involves the atrioventricular node (AV node) or the His-Purkinje system. When an impulse travels through these pathways but fails to produce a visible QRS complex on the ECG, it is considered "concealed." This can happen due to partial depolarization or refractoriness of the conduction tissue.

Atrioventricular Node

In the AV node, concealed conduction can occur when an impulse arrives during the refractory period of the node. The impulse may not be conducted to the ventricles, but it can alter the refractoriness of the AV node, affecting the conduction of subsequent impulses. This is often seen in arrhythmias such as atrial fibrillation or atrial flutter.

His-Purkinje System

In the His-Purkinje system, concealed conduction can occur when an impulse travels down one branch of the bundle of His but fails to depolarize the ventricles. This can lead to bundle branch block patterns on the ECG without a corresponding QRS complex.

Clinical Significance

Concealed conduction is important in the diagnosis and management of certain cardiac arrhythmias. It can influence the interpretation of ECGs and the effectiveness of antiarrhythmic drugs. Understanding concealed conduction helps in predicting the behavior of arrhythmias and in planning appropriate treatment strategies.

Related Pages

• Cardiac electrophysiology
• Atrioventricular node
• His-Purkinje system
• Electrocardiogram
• Arrhythmia