cardiology

The study of the heart, its physiology, functions and the diseases that affect it. (source)

Examples. Part of normal heart physiology is the cardiac pacemaker activity that keeps the heart beating.

A common form of heart disease is congestive heart failure.

Treatments for congestive heart failure include digitalis (dried Foxglove leaf) which contains cardiac glycosides.

Cardiac glycosides are poisons that inhibit the Na⁺,K⁺ pump and slow the heart rate.

Cardiology Explained - online textbook