Problem 5 - Biology of Aging

Question

Describe how coronary artery disease can lead to ventricular fibrillation and death.

Step-by-Step Solution

Answer

Coronary artery disease, characterized by plaque buildup in the coronary arteries, can lead to reduced blood flow to the heart muscle. This may disrupt the electrical system of the heart leading to irregular contractions, termed ventricular fibrillation. The resulting lack of blood circulation can cause brain damage and death within minutes.

Step 1: Understand Coronary Artery Disease (CAD)

CAD develops when the coronary arteries, the major blood vessels that supply your heart muscle with blood, oxygen and nutrients, become damaged or diseased. This is usually due to deposit of cholesterol-containing substances - plaque - on the inner walls of the arteries (atherosclerosis). Over time this plaque can narrow or block the arteries, reducing blood flow to the heart muscle. This can lead to pain known as angina, heart attack or other heart conditions.

Step 2: Link between CAD and Ventricular Fibrillation

Decreased blood flow to the heart muscle impairs its functionality, including the electrical system which coordinates the hearts rhythm. Ventricular fibrillation can occur resulting from the irregular heart rhythm initiated by the damaged heart muscle. During ventricular fibrillation, the lower chambers of your heart (the ventricles) experience irregular contractions which are rapid and chaotic impulses. This leads to the pumping mechanism of the heart not functioning properly.

Step 3: Ventricular Fibrillation leading to Death

As the heart's pumping action is disrupted during ventricular fibrillation, it cannot pump blood to the rest of the body, including the brain which consequently deprives the body tissue of oxygen. If not treated immediately, this can lead to brain damage and death within minutes. Therefore, ventricular fibrillation is a medical emergency.