Where does nonparoxysmal junctional tachycardia originate?

Nonparoxysmal junctional tachycardia originates from the atrioventricular (AV) node. This condition is characterized by a rapid heart rate that is typically irregular and occurs due to abnormal automaticity or re-entry circuits within the junctional area of the heart, which includes the AV node.

When the heart beats originate from the AV node, it indicates that the normal pacemaker function of the sinoatrial (SA) node is bypassed or impaired, leading to the AV node taking over as the primary rhythm generator. This can occur in various clinical scenarios, especially when there is a disease process affecting the SA node or in the presence of high vagal tone.

In contrast, other options relate to different locations within the cardiac conduction system: the SA node is the primary pacemaker of the heart, while the Bundle of His and Purkinje fibers are involved in conducting impulses through the ventricles. However, they are not the source of the rhythm in junctional tachycardia. The understanding of these distinctions is important in diagnosing and managing arrhythmias effectively.