Myocardial Infarction As An Irreversible Damage Of Myocardial Tissue
Myocardial Infarction As An Irreversible Damage Of Myocardial Tissue
First of all we have to know about the heart, heart is a fist-sized muscular organ that is located in the center of the chest behind sternum slightly titled to the left, it is basically double pump, it provides the force needed to circulate the blood through the two major circulatory systems and it is composed of four chambers (two thin walled blood receiving, the atria and two thick walled blood pumping, the ventricles). Myocardial infarction (acute myocardial infarction or MI) is a serious medical emergency in which blood flow to the heart is abruptly and completely blocked in coronary artery, ordinarily by atherosclerosis (plaque) which it is accumulation of fats, cholesterol, white blood cell ,calcium and other substances then it will become blood clot. When an individual having an acute myocardial infarction (MI) has abrupt chest pain that is felt behind the sternum and sometimes travels to the left side of the neck or left arm, more over the person may have sweating, vomiting, shortness of breath, nausea, anxiety, heartbeats, vomiting, fatigue and weakness. These symptoms are partially different in women because women experience fewer symptoms than men, however in some cases the person does not have chest pain, shortness of breath, sweating or other symptoms, these cases are called (silent) myocardial infarctions case. Most important risk factors to this disease are obesity, high blood pressure, elder age, lack of physical activity, previous cardiovascular disease, both type of diabetes, tobacco smoking, excessive of drinking alcohol, high levels of certain types of lipid in blood such as (triglycerides, low-density lipoprotein (LDL) cholesterol and other types of cholesterol), low levels of high density lipoprotein (HDL) cholesterol in blood, the use of amphetamines and cocaine and stressful, one of the most important risk factor is diabetes which it is an abnormality, body could not produce or could not response to the insulin hormone, it leads to hyperglycemia. The main way to determine if a person has had myocardial infraction (the investigations to diagnosis MI) are using echocardiogram (which it is ultrasound to provide moving picture on heart and vessels) and ECG (it is a simple test that is used to detect electrical signals produced by heart, also we can determine it by testing blood for substances that damaged heart muscle released it, common blood tests to diagnosis (MI) are both type of troponin (troponin I and troponin T) and creatine kinase (CK-MB). Let’s move on to the treatments of myocardial infarction, treatments for myocardial infarction are percutaneous coronary intervention also known as angioplasty which it is opening blocked blood vessels especially coronary artery to restore normal blood flow to heart by using balloon through a catheter (long thin tube) through a small puncture of arm or leg artery to blocked artery of the heart, also we can do thrombolysis also known as fibrinolytic therapy which it is the process of dissolution of blood clot by medications such as the (anistreplase, reteplase and streptokinase…..), immediate treatments for suspected myocardial infarction includes aspirin which it prevents further blood from clotting, sometime nitroglycerin and other pain medication is used to treat chest pain and also sometime doctors use oxygen supplement, in a case if the person has diabetes we can treat him or her by coronary bypass surgery Also known as coronary artery Bypass graft (CABG) surgery, it is a surgical process that surgeon uses another blood vessels from other area of your body to bypass damaged blood arteries in order to restore normal blood flow to your heart.
- tiredness after surviving myocardial infarction
- ischemic heart disease
- patients with diabetes and cardiovascular disease
Why some patients sometime complaining of tired after surviving myocardial infraction?
Some patients feels tired after surviving myocardial infarction because when Myocardium is damaged and prevented from having oxygenated blood flow during a myocardial infarction, scar tissue is formed on the damaged myocardium, it leads to reduce efficiency of pumping blood in the affected area (cardiac output reduced), it means blood flow in the body reduced too and it causes reducing supply of oxygen as well as nutrient in all of the body also wash out of metabolic waste reduced so it is why tiredness and fatigue produced and the level of this tiredness is depending on the location and size of the scar tissue. Like Dr. Pia alsen, Author of the study, observed:
“Many people experienced the tiredness as different and new, not related to physical effort, daily activity or a lack of rest; it occurred unpredictably and may not attributed to definite cause”
Sometime some medication that you are taking for the disease of the heart can also cause Tiredness , such as the statin drugs (which they are most common for cholesterol-lowering drugs, statin also known as lipid-lowering medicine and it reduces the illness and mortality in the person who are at high risk of cardiovascular disease , example of statin Crestor and Lipitor….) and beta blockers could make you feel tired (beta blockers are a group of drug also known as beta-adrenergic blocking agents, and it is used to reduction of high blood pressure, manage abnormal heart rhythms and to protect the heart from a second heart attack after a first heart attack, example of beta blockers atenolol and betaxolol…..etc.), it is important to know that tiredness can also be found in depression, iron deficiency, thyroid and other medical conditions. It is possible to have both heart disease and second condition that is also contributing to your tiredness. So every survivors of myocardial infarction need doctor’s advice for lifestyle because they will be tired even by taking shower.
What is ischemic heart disease and what is pathophysiology of ischemic heart disease?
Ischemia is define as inadequate blood supply (circulation) to a local place due to blockage of blood vessels supplying to that place, Ischemic heart disease which also known as coronary heart disease (CHD), it causes the loss of oxygen and nutrients to myocardial tissue (imbalance between supply of oxygen and demand of oxygen to the myocardium) because of poor coronary blood flow(because of narrowed coronary artery) and the metabolic waste product accumulates is myocardium, this disease is nearly epidemic in the western world. About 250,000 people a year die in the United States because of ischemic heart disease without being hospitalized. It is more prevalent in white and elderly age. But how it happens? Atherosclerosis is the most common cause of ischemic heart disease (CHD). Atherosclerosis is known as fibrous fatty plaque which it is accumulations of fatty (especially LDL cholesterol), fibrous cap (collagen and smooth muscle), foam cells (macrophages, smooth muscle) which they are necrosis because of keep engulfing LDL cholesterol , possibly including calcium deposits and endothelium covers all of it, gradually narrow the coronary artery lumens, which reduces the volume of blood that can flow through them. This can lead to myocardial infarction (a temporary deficiency of blood flow to the heart) and eventually necrosis (heart tissue death). Atherosclerosis has two types (stable plaque and unstable plaque) the difference is in the proportion of the structure, stable plaque has [ fibrous cap which it is thick, less foam cells (macrophages and large smooth muscles containing LDL cholesterol) and less extracellular fat] it has less chance to rupture so it is why it is called stable plaque, in opposite unstable plaque has [ fibrous cap which it is thin, less foam cells (macrophages and large smooth muscles containing LDL cholesterol) and more extracellular fat] because of thin fibrous cap this type is unstable and has more chance to rupture and create blood clot. When endothelium with basement membrane have been damaged because of hypertension (high blood pressure), stress and any toxic material such as nicotine from smoking…. plaque material are really thrombogenic so because of the primary homeostasis , a lots of platelets attaches to the collagen and accumulates with red blood cells then coagulation cascade has been activated and secondary homeostasis will initiate, it stimulates more platelet to accumulates and fibrin clot formed, so blood clot formed and coronary artery blocked. Most people with 70% luminal obstruction do not experience the limitation of the blood flow and symptoms of ischemic heart disease while they are at rest, It occurs when the oxygen demand increases (usually during emotional stress and exercise), but people with 90% luminal obstruction can experience the limitation of blood flow and the symptoms of it at any situation even during rest. We should be aware of that most cases of ischemic heart disease involves left ventricle, a few cases of ischemic heart disease involves right ventricle, this difference refers to the properties of left ventricle and right ventricle, left ventricle has 1.5 thickness, high tension and its pressure is about 0-120 millimeter mercury so it needs more oxygen but right ventricle has 0.3 to 0.5 thickness, low tension and its pressure is about 0-25 millimeter mercury so it needs less oxygen. Ischemic heart disease has four types (myocardial infarction, stable angina, cardiac sudden death, unstable angina). Genes implicated with ischemic heart disease, Overwhelming evidence confirms a genetic link to ischemic heart disease (CHD). Researchers have identified more than 250 genes that may play a role in ischemic heart disease, ischemic heart disease commonly results from combined effects of multiple genes. These effects make the genetics of Ischemic heart disease very complicated because many genes can influence a person’s risk. Some of the most important genes linked to ischemic heart disease include [low density lipoprotein (A protein that removes LDL from blood stream, a mutation in this Gene is responsible for familial hypercholesterolemia), apolipoprotein E, apolipoprotein B and apolipoprotein A…..etc.]. Treatment of ischemic heart disease is near to the treatment of myocardial infarction, but it Focus more on 3 goals (reducing myocardial oxygen demand, increasing the oxygen supply, alleviating pain), also controlling modifiable risk factors is really important. Interventions may be non-invasive or invasive.
How patients with diabetic mellitus present?
Diabetes is an important risk factor and major cause of cardiovascular disease and development of coronary artery disease, unfortunately patients with diabetes suffer more from an excess coronary artery disease and patients with diabetes mellitus present in as many as 30% of patients hospitalized with acute myocardial infarction. Mortality rate in the patients with diabetic in acute myocardial infarction was reported to be very high and at least double the mortality rate in the patients without diabetes, despite improvement of the treatment of acute myocardial infarction, the mortality rate of the patients with diabetes is still double compare with patients without diabetes. After adaptation of the size of infarction (injury), patients with diabetes have more chance to have a congestive heart failure than patients without diabetes. Diabetes leads to hyperglycemia which it associates with obesity, hypertension, and dyslipidemia and diabetes is an important factor to increase atherosclerosis plaque formation and thrombosis, the pathophysiology of vascular damage in diabetes is complex and involves abnormalities in endothelial cells, vascular smooth muscle cells, and platelet function, As a result of all these pathological changes, the development of atherosclerotic, patients with diabetes appear to have a greater number of ruptured plaques, plaques in people with diabetes is a complex progressive process, characterized by early vascular inflammation and endothelial dysfunction, leading to monocyte recruitment and subsequent formation of fatty streaks. Over the years, this leads to atherosclerotic plaques that in a pro inflammatory and pro-thrombotic context become unstable and prone to rupture. The choice of the most appropriate (glucose-lowering medications) will help the physicians to reduce the excess of cardiovascular risk in diabetic patients. Patients with diabetes have higher levels of triglycerides and very low density lipoprotein cholesterol (VLDL) and lower levels of high density lipoprotein cholesterol (LDL) than do patients without diabetes, patients with diabetes have high levels of plasma protein and increase it red cell aggregation and possibly decrease red cell deformability, induced platelet aggregation have been shown to be higher in patients with diabetes than in patients without diabetes, plasma fibrinogen levels are elevated in diabetic patients and have been shown to correlate with myocardial infarction and sudden death in diabetic men because of the rapid formation of blood clot, factor VIII and factor VIII ristocetin cofactor are elevated in diabetic patients, fibrinopeptide A in thrombin may also be elevated in diabetic patients, also because of the deficient production of prostacyclin, endothelial dysfunction or damage is more in patients with diabetes and preventing a normal repair of ongoing endothelial damage, that is why mortality rate by myocardial infarction is double in patients with diabetes compare patients without diabetes. Screening for Coronary Artery Disease in Diabetic Patients, Coronary artery disease (CAD) is often asymptomatic in diabetic patients, and up to sixty percent of myocardial infarctions may be clinically silent and detected only by systematic electrocardiogram screening, these patients often experience atypical symptoms of ischemia such as fatigue or shortness of breath during physical activity in the absence of typical chest pain.
Myocardial infarction or heart attack is an irreversible damage of myocardial tissue caused by lack of oxygenated blood due to atherosclerosis and blood clot in coronary artery, then myocardial tissue may become necrosis. Because of the physiological changes of the heart after myocardial infarction, the person that survived from myocardial infarction has unidentified and unexperienced tiredness (fatigue), and they have never been tired like that, the level of tiredness is depending on the location and size of damaged myocardial tissue. Ischemic heart disease that is known as coronary artery disease is a situation that blood flow has been reduced to the myocardial tissue and it leads to imbalance between oxygen supply and oxygen demand, it has many reason but most important and most common cause is atherosclerosis which it is accumulation of fat, macrophages, smooth muscle and calcium…..etc. So because of the atherosclerosis the coronary artery narrowed and blood flow has been reduced to that specific area of myocardial tissue. Patients with diabetes are at high risk to die by myocardial infarction (MI) due to physiological changes that occurs inside diabetic patients, they have a lots of unstable atherosclerosis plaque and so they will rupture at any time, it is why patients with diabetes need more screening.