What kinds of patterns indicate disturbances in the conduction system on ecg?

Conduction dis (CD) : Cd is reliably identified on ecg. Broadly speaking, it includes right bundle branch block (rbbb), left bbb, so-called left fascicular blocks, and non-specific conduction delays. Each has its own significance, with isolated fascicular blocks being the most benign. These patterns usually remain stable for years, even decades, but sometimes progress, so they do need follow up.