[header] How to identify heart blocks [title] Understand what the term " heart block " refers to. [step] The term heart block refers to an av block or an atrio-ventricular block. This is when there is some obstacle blocking electrical signals between the upper and lower chambers of the heart. 
[substeps] There are three degrees of av block according to severity-first degree, second degree and third degree. Second degree heart blocks have two subtypes.