Progressive Familial Heart Block, Type Ia, also known as bundle branch block, is related to brugada syndrome 1 and ventricular fibrillation, paroxysmal familial, 1, and has symptoms including chest pain, dyspnea and syncopal episode. An important gene associated with Progressive Familial Heart Block, Type Ia is SCN5A (Sodium Voltage-Gated Channel Alpha Subunit 5), and among its related pathways/superpathways are Nervous system development and Activation of cAMP-Dependent PKA. The drugs Prednisolone and Prednisolone acetate have been mentioned in the context of this disorder. Affiliated tissues include heart and atrioventricular node, and related phenotypes are prolonged pr interval and right bundle branch block