Electrical signals pass through the atrioventricular node, His bundle, left and right bundle branches, and are transmitted to the Purkinje’s fiber, causing the left and right ventricles to contract. When the normal path of electrical conduction is delayed or closed, it is called conduction interruption. Atrioventricular block refers to any blockage between the SA node and the Purkinje’s fiber.

First-degree atrioventricular blockage refers to cases where atrioventricular nodules and conduction delays appear in the heath. First-degree atrioventricular blockade is correct to see as a delay rather than blockage because electrical stimulation is eventually transmitted to the ventricle even though there is a conduction delay in the atrioventricular node or His bundle. First-degree atrioventricular block can be diagnosed when the PR Interval is more than 0.2 seconds and more than 5 small scales on the ECG.

In general, there are no symptoms, but some may feel irregular heartbeat, presyncope or fainting. There are times when the conduction between the atrium and the ventricle is incomplete and sometimes not. Mobitz type 1 is common, and the PR interval gradually increases, and conduction is blocked. This can be found at bedtime in healthy people and do not require special treatment. However, the Mobitz type 2, where conduction is blocked after the PR interval is constant, may require an artificial pacemaker to be inserted, similar to the third-degree atrioventricular block.

A phenomenon in which no electrical signal is transmitted to the ventricle. Although the atrium and the ventricle are physically connected, they are electrically insulated so that an electrical signal cannot flow to the ventricle. It can be caused by acquired or congenital causes and shows a phenomenon in which all P waves and QRS complexes are dissociated on the electrocardiogram.

The PR Interval is also referred to as the PQ interval, and refers to the interval from the origin of the P wave to the origin of the QRS group. This PR interval represents the time it took for the electrical stimulation of the atrium to pass through the atrioventricular node to the His bundle. The normal PR interval is within 200ms. It is generally harmless but may be associated with Wolff-Parkinson-White syndrome (a symptom that occurs when the heart contracts faster than normal).

WPW syndrome is the most common cause of paroxysmal supraventricular tachycardia (PSVT) in children and infants and can be inherited from parents. 70% of all patients are male, and about 70% do not have other heart disease.

In the case of a normal heart, the SA node sends an electrical signal to a specific path to regulate the cycle of the heart rate, but in WPW syndrome patients, the electrical impulse is transmitted early from the heart through a subconductor, causing paroxysmal supraventricular tachycardia. In severe cases, increased heart rate can lead to sudden death due to fainting or ventricular tachycardia.