Atrioventricular block second-degree


Advocate Christ Medical Center


An electrical impulse from the sinoatrial node has to travel through the atria, to the atrioventricular node, and down the His-Purkinje system to reach the ventricles and create a ventricular contraction. This process is reflected on ECG as the PR interval which leads to a QRS complex. A delay in conduction in this system results in an atrioventricular conduction block or a prolongation of the PR interval on ECG. Conduction blocks are classified as either first-degree block, second-degree block, or third-degree block. The second-degree atrioventricular block is the focus of this activity. There are two types of second-degree atrioventricular blocks: Mobitz type I, also known as, Wenckebach and Mobitz type II.

In general, patients with second degree AV block may have no symptoms or may experience symptoms like syncope and lightheadedness.The second degree heart block may be temporary or permanent, depending on the impairment of the conduction system.

The mobitz type ll block does have the potential to progress to a complete heart block and if unrecognized, can lead to death.

Document Type

Book Chapter

PubMed ID


Book Chapter/Book Details

StatPearls Publishing. Treasure Island (FL)

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