Myocardial Infarction

The most common physiological process leading to a myocardial infarction is the occlusion of coronary arteries by a process known as atherosclerosis. In fact, atherosclerosis is present in more than 90% of persons with coronary heart disease.1

Another word used to describe a heart attack is myocardial infarction, cardiac infarction and coronary thrombosis. A heart attack is the death of a part of the heart caused by the loss of blood supply. The blood supply is usually gone due to a coronary artery being blocked by a blood clot. When a part of a heart artery breaks a blood clot forms around the piece. This blood clot can block the blood flow through the heart muscle. When the heart muscle needs oxygen it is called ischemia. When damage of a part of the heart muscle happens it’s called a heart attack. During a heart attack damage occurs depending on the size of the area blocked by the blood clot as well as the time between the actual heart attack and the treatment. Even though the heart may be hurt, the rest of the organs work with no problems. However, it will not pump as much blood as it used to in order to supply the same amount of blood to all of the parts of the body.

|Required: |Heart |The heart and circulatory system | Coronary artery disease (narrowing of the |

A heart attack occurs when an artery that supplies blood to the heart becomes blocked. The loss of oxygen and nutrients damage the heart's muscle tissue, causing the remaining healthy tissue to pump even harder to keep up.

Nevertheless, there is an understandable and noticeable link between circulatory related diseases and lifestyle diseases, such as Coronary Heart Disease. Coronary heart disease can occur when fatty acids, such as cholesterol in an inadequate diet, build up in the walls of the coronary artery. These fatty deposits collect minerals and harden to become a plaque. Eventually, this plaque grows and can swells up, forming an aneurism. In some cases, this aneurism may burst leading to instant death. As it continues to grow and swell up, it finally blocks the artery completely and forms blood clots. This is known as coronary thrombosis. A myocardial infarction, or in other words as heart attack, occurs when no oxygen is able to reach the coronary artery and thus it is unable to fulfil its role in providing the heart muscle with a sufficient supply of blood. Heart attacks are very common in the society nowadays, especially occurring in smokers or obesity related diseases (Millar, June 2014)

Clearly differentiate the pathophysiology of angina and myocardial infarction, including signs and symptoms. (5 marks)

Myocardial Infarction (MI) is more commonly referred as the heart attack. This typically occurs due to an interruption, albeit partial to some part of the heart, which causes the cells in the heart to die and as a result sends

For this myocardial infarction, the right coronary artery was blocked. The parts of the heart that were affected by this blockage was the right atrium, the right ventricle, the interventricular septum, the Sinoatrial node and the AV node, and some parts of the left atrium and ventricle. These parts were affected because the right coronary artery supplies blood to these parts of the heart; since there was a blockage the blood was not able to continue through the right coronary arteries into its branches, which are the sinoatrial nodal artery, the right marginal branch, the posterior interventricular branch, and the atrioventricular nodal artery (Gest).

Consequences of left ventricular systolic dysfunction include ischemic diseases, atrial fibrillation, increased ventricular response, and myocardial infarctions2. Some of these symptoms were seen in the patient from the case study. Factors leading to left

Left sided heart failure causes a decrease in cardiac output and can be further classified as systolic or diastolic. When the cardiac output is decreased and can not get enough oxygen to important organs, it is from an imbalance of stroke volume and heart rate. When a person experiences a myocardial infarction or continuous hypertension, the contractility of the heart decreases which directly influences the stroke volume. The stroke volume is the amount of blood pumped out of the heart per contraction so if that decreases, so does the cardiac output which decreases perfusion of the organs (Huether and McCance, 2012). Diastolic heart failure in the left side is when the ventricle has trouble filling to its full capacity which is usually caused by a stiffening or loss of contractility of the ventricle.

The coronary artery that was occluded in M.T.’s coronary circulation were the right coronary artery. When coronary blood flow is interrupted for an extended period, myocyte necrosis occurs. This results in MI. In the majority of MI, the decrease in coronary flow is the result of atherosclerotic CAD (McCance & Huether, 2014). M.T. is experiencing transmural MI. According to H. Michael Bolooki (2010), a transmural MI is characterized by ischemic necrosis of the full thickness of the affected muscle segment(s), extending from the endocardium through the myocardium to the epicardium. M.T. was exhibiting crushing substernal chest pain radiating down his left arm. He was complaining of dizziness and nausea. During M.T.’s physical exam, he

The heart is an organ that pumps blood from the body and maintains all the organs functioning to keep one alive; when one of the arteries that receive blood is blocked it can cause a heart attack or myocardial infarction (MI). “During a heart attack, the heart muscle (the myocardium) is damaged, and part of it die from lack of blood” (book, p. 429).

Decreased blood flow to the heart muscle can cause an ischemic episode that often presents with chest pain and damages the heart.1

The right and left side of the heart are similar in structural components. Both sides contain a AV valve, semilunar outflow valve and smooth and muscular parts. The main difference between the two sides is size. The muscle of the left ventricles is thicker than the right side. The cavities are the same size and pump the same amount of blood. The left ventricle pumps with more power to profuse the entire body. The right ventricle profuse the lungs. The systemic resistance of the left ventricle is much higher than the pulmonary flow. The right

Arteriolar vascular constriction, heart rate increases, and renal retention of sodium and water all help to regulate cardial output. Ventricular dilatation is commonly seen. A large amount of ventricular myocardium is lost, contractility may be greatly compromised, and cardiogenic shock may ensue.