What rhythm is identified by having a PR interval longer than 0.20 seconds?

A PR interval longer than 0.20 seconds indicates a specific type of conduction delay within the heart's electrical system, known as a first-degree atrioventricular block. In this scenario, the electrical signals from the atria to the ventricles are delayed, resulting in a longer PR interval.

In a first-degree block, although all the signals reach the ventricles, the prolonged PR interval reflects this delay without any dropped beats. This is crucial because it distinguishes a first-degree block from more severe blocks where some signals may not be conducted at all.

The other rhythms mentioned, such as 2nd Degree Block and Complete Heart Block, have different criteria and characteristics. For instance, in a 2nd Degree Block, not all atrial impulses are conducted, leading to dropped beats. Complete Heart Block completely disrupts the electrical signals from the atria to the ventricles, resulting in independent rhythms. A normal sinus rhythm, on the other hand, has a normal PR interval of 0.12 to 0.20 seconds, which does not exceed the 0.20-second threshold.

Therefore, the identification of a rhythm with a PR interval longer than 0.20 seconds aligns with the characteristics of a first-degree AV block