Junctional tachycardia is characterized by which of the following?

Junctional tachycardia is characterized by which of the following?

• A. PR intervals less than 0.12 seconds
• B. PR intervals greater than 0.20 seconds
• C. Regularly interspersed P waves
• D. Unevenly spaced QRS complexes

Answer: (A)

In junctional tachycardia, the defining feature of the PR interval is that it is typically less than 0.12 seconds. This occurs because the tachycardia originates from the AV junction, which leads to a shorter conduction time through the atria to the ventricles. In this condition, the impulses can bypass the normal pathways or arise from areas close to the AV node, thus resulting in a shorter PR interval compared to other atrial arrhythmias where the impulses would need more time to travel through the atria. The characteristics of the P waves in junctional tachycardia can be variable; they may be absent, inverted, or occur after the QRS complex, depending on the specific mechanism and location of the ectopic focus. Therefore, the lack of regularly interspersed P waves further confirms the diagnosis, in contrast to other types of arrhythmias that might show these features. Similarly, the QRS complexes are typically narrow in junctional tachycardia, as the ventricles are depolarized normally; thus, unevenly spaced QRS complexes are not a typical feature of this rhythm. Overall, recognizing the characteristic PR interval of less than 0.12 seconds in junctional tachycard

In junctional tachycardia, the defining feature of the PR interval is that it is typically less than 0.12 seconds. This occurs because the tachycardia originates from the AV junction, which leads to a shorter conduction time through the atria to the ventricles. In this condition, the impulses can bypass the normal pathways or arise from areas close to the AV node, thus resulting in a shorter PR interval compared to other atrial arrhythmias where the impulses would need more time to travel through the atria.

The characteristics of the P waves in junctional tachycardia can be variable; they may be absent, inverted, or occur after the QRS complex, depending on the specific mechanism and location of the ectopic focus. Therefore, the lack of regularly interspersed P waves further confirms the diagnosis, in contrast to other types of arrhythmias that might show these features. Similarly, the QRS complexes are typically narrow in junctional tachycardia, as the ventricles are depolarized normally; thus, unevenly spaced QRS complexes are not a typical feature of this rhythm.

Overall, recognizing the characteristic PR interval of less than 0.12 seconds in junctional tachycard