In normal individuals, the AV node slows the conduction of electrical impulses through the heart. This is manifest on a surface electrocardiogram (ECG) as the PR interval. The normal PR interval is from 120 ms to 200 ms in length. This is measured from the initial deflection of the P wave to the beginning of the QRS complex. In<unk> -degree heart block, the diseased AV node conducts the electrical activity more slowly. This is seen as a PR interval greater than 200 ms in length on the surface ECG. It is usually an incidental finding on a routine ECG.<unk> -degree heart block does not require any particular investigations except for electrolyte and drug screens, especially if an overdose is suspected.
First-degree atrioventricular block
Second-degree atrioventricular block
Third-degree atrioventricular block
Ventricular escape beat
AV nodal reentrant tachycardia
Wandering atrial pacemaker
Re-entry ventricular arrhythmia
Left bundle branch block