First-Degree Atrioventricular Block, also known as first degree atrioventricular block, is related to syncope and progressive familial heart block, type ia. An important gene associated with First-Degree Atrioventricular Block is SCN5A (Sodium Voltage-Gated Channel Alpha Subunit 5), and among its related pathways/superpathways are Cardiac conduction and Antiarrhythmic Pathway, Pharmacodynamics. Affiliated tissues include heart and atrioventricular node, and related phenotypes are muscle and cardiovascular system