what exactly is a blockage in the middle of the heart
Thanks for your question.
This most likely is describing a blockage of a coronary artery that feeds the anterior wall of the heart.
Coronary arteries are the blood vessels that feed the heart muscle itself. If a blockage forms in these arteries, the heart muscle is deprived of the oxygen it needs to carry on its pumping function. When deprived of blood flow and oxygen, patients can experience chest discomfort often described as aching, sharp, squeezing, tightness, and many others. Every patient is different. If this blockage is is severe enough, the area can experience a loss of oxygen and the muscle becomes damaged. This is the mechanism for a heart attack.
As for location, there are three main coronary arteries. The Right Coronary Artery feeds the bottom of the heart known as the inferior wall. The Circumflex artery feeds the back of the heart or posterior wall. And the Left Anterior Decending Artery feeds the front of the heart known as the anterior wall. This could also be described as the middle of the heart. These major arteries break into several smaller branches as they travel to the heart. Blockages can occur in any vessel, large or small. The larger the vessel blocked, the more area of the heart that is affected. When doctors talk about the "walls" of the heart, we are talking about the left ventricle, the main pumping chamber of the heart. The smaller right ventricle is important also, but much of its pumping action is also done by the left ventricle. The ventricles are separated by a wall of muscle called the septum.
Blockages are usually caused by a buildup of atherosclerotic plaque which is composed of cholesterol/other fats/ and calcium. As a plaque enlarges, the opening in the vessels is decreased, allowing less blood and oxygen to get to the heart muscle. Another problem other than gradual increase in the size of plaques is the rupture of a plaque. In this situation, factors cause these plaques to be unstable and actually break open or rupture. This is followed quickly by clot formation on the plaque which blocks the artery very quickly and causes an acute cardiac event. If treatment is obtained quickly, damage can be minimized by opening this blockage before muscle damage is extensive.
When doctors talk about the amount of blockage, we often talk about percentages. This percentage is made at the time of cardiac catheterization when the vessels and the blockages are directly visualized. A blockage of 70 % or more is considered significant.
I hope this information was helpful.
Martin Cane, M.D.