Atrioventricular (AV) refers to the anatomical and functional connection between the atria and ventricles of the heart, primarily involving the AV node and AV valves that regulate electrical conduction and blood flow. It is crucial in clinical practice because proper AV conduction ensures coordinated ventricular contraction and effective cardiac output, while dysfunction can lead to arrhythmias or heart block. A key clinical association is AV block, where impaired conduction through the AV node causes bradycardia and may require pacemaker implantation.