What is substrate in cardiology?

In cardiology, "substrate" refers to the underlying anatomical or electrophysiological characteristics of the heart that predispose it to arrhythmias. This can include structural changes such as fibrosis, hypertrophy, or scarring, as well as electrical abnormalities that affect conduction pathways. Identifying the substrate is crucial for understanding the mechanisms of arrhythmias and for developing targeted treatments, such as catheter ablation, to restore normal heart rhythm.