This video describes how the circulatory system works, how disease can affect blood vessels (atherosclerosis), and how doctors use angiography to test for coronary artery blockage.

Tiny electric currents flow through the heart muscle and cause them to contract, squeezing blood throughout the body. This animation shows the electrical system of the heart and how it is driven by a small patch of tissue called the cardiac pacemaker or sinoatrial node.

This animation shows what angioplasty and stent deployment look like if you could see inside of the blood vessels, up close. There is no narration, but the "balloon" being opened is the angioplasty procedure while the "chicken-wire" cylinder is the stent.

A physician describes what cholesterol is, the difference between good and bad cholesterol, and how cholesterol leads to atherosclerosis (blood vessel disease).