During an EKG, which of the following findings is indicative of supraventricular tachycardia (SVT)?

Supraventricular tachycardia (SVT) is characterized by a rapid heart rate that originates above the ventricles, typically in the atria or atrioventricular (AV) node. The hallmark of SVT on an electrocardiogram (EKG) is narrow QRS complexes with a regular rhythm. This indicates that the electrical conduction is occurring normal through the ventricles, allowing them to respond appropriately to the rapid impulses coming from the atria.

In SVT, the heart rate usually exceeds 100 beats per minute, but the distinguishing feature lies in the morphology of the QRS complex—narrow QRS complexes signify that the origin of the electrical impulses is supraventricular. This contrasts with ventricular tachycardia, which would be indicated by wide QRS complexes. The regular rhythm further supports the diagnosis of a reentrant or ectopic mechanism typically seen in SVT.

The presence or absence of distinct P waves can vary in SVT cases; sometimes they may not be visible due to their merging with the QRS complexes when the heart rate is very rapid. Thus, the identification of narrow QRS complexes coupled with a regular rhythm is crucial in diagnosing SVT effectively.