What does the prefix “cardio-” refer to?

The prefix “cardio-” comes from the Greek word kardia, meaning heart. It is used in medical terminology to describe anything related to the heart and the cardiovascular system. For example, cardiology is the branch of medicine that studies heart diseases and their treatments, while cardiovascular refers to both the heart and the blood vessels. Terms like cardiogram (a record of heart activity) and cardiologist (a heart specialist) also use this prefix. Understanding this root helps in identifying medical conditions related to heart health, such as cardiomyopathy or cardiomegaly.