What is the classic EKG finding associated with supraventricular tachycardia (SVT)?

Supraventricular tachycardia (SVT) is characterized by a specific pattern on an electrocardiogram (EKG). The classic finding for SVT includes a regular rhythm, a fast heart rate (typically exceeding 100 beats per minute), and narrow QRS complexes. This rapid heart rate originates above the ventricles, often involving the atria and the AV node, thereby leading to the regularity observed in the rhythm.

The regular nature of the rhythm is significant because, unlike other tachycardias that can be irregular, SVT typically maintains a consistent rhythm, which is a critical aspect of its identification. The narrow QRS complexes occur because the ventricular depolarization is normal and does not show any delay, which would be indicated by a wider complex. Fast heart rates during episodes of SVT can range anywhere from 150 to 250 beats per minute, making recognition of this pattern essential for accurate diagnosis and appropriate treatment.

In summary, the EKG finding of a regular, narrow complex, fast rhythm is essential for identifying SVT and allows clinicians to differentiate it from other types of tachycardia that may present differently.