A first-degree, or 1 st degree, AV block is indicated on the ECG by a prolonged PR interval, as seen below. Recall that the P wave indicates atrial depolarization, initiated by firing of the SA node.

This ECG has both second degree AV block with 2:1 block and second degree type I AV ... Note the irregular R-R intervals making 3rd degree heart block unlikely. The rhythm on this ECG needs ...

Healthcare providers categorize second-degree heart block subtypes—Mobitz type 1 and type 2—based on their physical signs on an electrocardiogram (ECG), which records the electrical activity ...

ECG interpretation in athletes requires careful analysis to properly distinguish physiological changes related to athlete's heart from findings suggestive ... sinus arrhythmia and 1° atrioventricular ...