First-Degree AV Block

Every atrial impulse conducts, with a prolonged PR interval.

Programmatically generated teaching example. Morphology and supporting values are simplified.

Typical rate: Underlying rate varies
Regularity: Regular
P waves: One P for each QRS
PR interval: >200 ms; constant
QRS: Usually narrow

Sources and review status

This guide uses RhythmDock’s centralized educational definitions. See reference sources and limitations. Published September 13, 2026. Independent medical review is pending; this is not a clinical interpretation tool.