Second-degree atrioventricular block

Second-degree atrioventricular block
Other names	Second-degree heart block
ECGs demonstrating forms of second-degree AV block
Specialty	Cardiology
Symptoms	Dizziness, Fainting, Shortness of breath
Types	Type 1 (Wenckebach), Type 2
Causes	Fibrosis in AV node, medication, vagal tone, electrolyte disturbances
Diagnostic method	Electrocardiogram
Treatment	Avoidance of AV-nodal-blocking medication, pacemaker

Second-degree atrioventricular block (AV block) is a disease of the electrical conduction system of the heart. It is a conduction block between the atria and ventricles. The presence of second-degree AV block is diagnosed when one or more (but not all) of the atrial impulses fail to conduct to the ventricles due to impaired conduction. It is classified as a block of the AV node, falling between first-degree (slowed conduction) and third degree blocks (complete block).^[1]