Anatomy of the Heart
The heart is a
muscular organ composed of four chambers: two upper chambers called atria
and two lower chambers called ventricles. These four chambers pump blood
through the body in a rhythmic pattern with the help of the four valves in
the heart. The movement of blood through the body can be felt at the wrist
or neck and is known as the pulse.
Although the heart is
full of blood, it cannot receive oxygen and nutrients from the blood inside
the chambers. The heart muscle must rely on the arteries on the surface of
the heart to nourish it and keep it working properly. These surface arteries
are known as the coronary arteries. There are three main coronary arteries:
the right coronary artery, the left anterior descending coronary artery and
the circumflex coronary artery. These three arteries branch into thousands
of small arteries like a tree trunk branches into limbs, bringing oxygen and
nutrients to the heart muscle cells.
Coronary
Artery Disease
 Occasionally,
these arteries become narrowed due to a build-up of fat, cholesterol and
calcium and cannot carry enough oxygenated blood to the muscle. This
picture shows a constricted Left Anterior Descending (LAD) artery. This
reduced flow of blood through the narrowing is a lot like what happens to
the plumbing in our homes as the pipes become clogged with a build-up of
mineral deposits - not as much water can flow. The term "coronary
artery disease" refers to any abnormal condition of the coronary
arteries that interferes with the delivery of an adequate supply of blood to
the heart muscle. More than 95 percent of all coronary artery disease
is due to atherosclerosis (cholesterol and calcium deposits).
When the heart muscle
does not get enough oxygenated blood to meet its demands, it experiences a
hunger for more oxygen. This hunger is felt by the patient as a
painful tightening, pressure, or fullness in the chest which we term
"angina pectoris". Total occlusion of a coronary artery
leads to a heart attack (myocardial infarction). In order to treat coronary
artery disease most effectively, we must have an accurate picture of the
coronary arteries. The only way we can actually see these arteries is by
injecting dye into them during a cardiac catherization. This procedure is
called coronary angiography.
Cardiac
catheterization is also useful in diagnosing other disorders of the heart
such as defective heart valves, muscle disease and other problems of
the heart, lungs, and blood vessels. |