In-depth analysis of acute myocardial infarction: identifying high-risk groups, early warning signs, and the "devil's hour"

Section 3 Myocardial Infarction With the improvement of people's living standards in my country, the incidence of hyperlipidemia, hypertension, and coronary heart disease has also increased significantly. Acute myocardial infarction is a very serious type of coronary heart disease, caused by coronary artery occlusion and interruption of blood flow, leading to local necrosis of part of the myocardium due to severe and persistent ischemia, resulting in serious damage to cardiac function and a high mortality rate. Statistics show that one-third to one-half of patients die before reaching the hospital. A small number of coronary heart disease patients experience a rapid and severe onset with a poor prognosis; some even suffer sudden death, which should raise awareness. Causes of sudden death from coronary heart disease: ① Sudden infarction of the main coronary artery supplying blood to the heart (usually caused by thrombosis), leading to large-area acute ischemia and necrosis of the myocardium; ② Lack of nutrition to the myocardium after acute myocardial infarction, leading to myocardial rupture; ③ Coronary artery spasm occurring on the basis of atherosclerosis, leading to cardiac electrophysiological disturbances and causing serious arrhythmias (such as ventricular fibrillation).

I. High-Risk Groups for Myocardial Infarction Myocardial infarction, or ischemic necrosis of the myocardium, clinically manifests as chest pain, acute circulatory dysfunction, and acute myocardial injury, ischemia, and necrosis. This releases myocardial enzymes, increasing their activity in the blood and causing progressive changes on the electrocardiogram. 90% of myocardial infarctions are caused by coronary atherosclerosis, with a smaller number caused by syphilitic aortitis, coronary artery infarction, and coronary artery spasm. Myocardial infarction is often preceded by significant triggers, such as emotional fluctuations, excessive physical exertion, overeating, high-fat diets, infections, surgery, and shock; sometimes it can even occur during sleep. To prevent myocardial infarction, we must ensure the heart gets sufficient rest, guarantee adequate sleep, avoid overeating to prevent obesity, refrain from smoking and excessive alcohol consumption, pay special attention to keeping warm in winter, limit physical activity, and maintain mental calm. Furthermore, a stable daily life is also crucial. The more risk factors a high-risk group for myocardial infarction possesses, the greater their chance of developing the disease. (1) The incidence rate is high in men over 45 years of age or women over 55 years of age. (2) Smoking is also a very important risk factor for myocardial infarction. (3) People who lack exercise, including those with high blood pressure, obesity, high cholesterol, etc. (4) People with high work pressure, mental stress, irregular work and rest schedules are more susceptible to the disease.

II. The Sudden Onset and High Mortality Rate of Myocardial Infarction in Middle-Aged Individuals Myocardial infarction occurs because the inner lining of the arteries supplying blood to the heart is damaged. Lipids then accumulate at the site of the defect. When this accumulation reaches a certain level, a plaque forms on the inner lining. Rupture of the plaque causes a thrombus, blocking the blood vessel, leading to myocardial ischemia, arrhythmia, and sudden death. This is analogous to an iron pipe where rust inside roughens the surface, causing dirt accumulation. When this dirt accumulates to a certain extent, the flow of water is reduced. If the dirt breaks off, it can clog lower branch pipes, preventing blood flow. This example illustrates how a blockage in the coronary arteries supplying blood to the heart leads to myocardial ischemia and myocardial infarction. High-risk groups for this disease include obese individuals, those with fast-paced work schedules, those who engage in excessive mental work and little physical work, men over 50, postmenopausal women, heavy smokers, and those with hypertension, hyperlipidemia, or hyperglycemia.

III. Most People Experience Warning Signs of Myocardial Infarction Many people believe that myocardial infarction is a disease that only affects people in their sixties and seventies. However, in recent years, a significant proportion of patients rushed to the hospital for acute myocardial infarction are middle-aged people aged 40-50. Even more worrying is that acute myocardial infarction in middle-aged people tends to be more sudden and has a higher mortality rate. However, myocardial infarction has a slow progression. As the plaque enlarges, the blood vessels narrow, causing poor blood flow. Most people experience warning signs, such as brief chest discomfort like chest tightness, chest pain, and shortness of breath after exercise, which usually subside after a short rest. Therefore, people often mistakenly attribute these symptoms to overexertion and do not take them seriously. It is worth noting that many middle-aged people have almost no symptoms, but this disease has already quietly developed in their cardiovascular system. Because the plaque in their blood vessels is still relatively small, they are unaware that they have the disease. Because they often experience no symptoms, if plaque in their blood vessels suddenly ruptures and blocks the vessel, causing symptoms such as chest tightness and chest pain, they may not realize it could be a fatal acute myocardial infarction. They often miss the opportunity for medical attention and rescue, making death particularly sudden. Excessive fatigue, emotional excitement, changes in weather, and overeating can easily trigger acute myocardial infarction.

IV. The most common time for acute myocardial infarction: Middle-aged and elderly people in high-risk groups are particularly prone to acute myocardial infarction during the period from midnight to waking up or after strenuous exercise. In other words, acute myocardial infarction is more common in the latter half of the night until dawn. Experts believe that during sleep, the vagus nerve is dominant, while after waking up, the sympathetic nervous system is dominant. Therefore, there is a transition period from sleep to wakefulness, during which the body's organs are less adaptable. In addition, the body is relatively dehydrated during sleep, increasing blood viscosity, making this the most vulnerable time for acute myocardial infarction. Blood pressure is generally higher upon waking up in the morning. This is why many middle-aged and elderly people frequently experience acute myocardial infarction when getting up to urinate in the middle of the night or upon waking up in the early morning. People with hypertension, hyperlipidemia, and diabetes, as well as those in the elderly with other health conditions, should be wary of these "devilish times." Experts say that, based on clinical experience, besides those with "three highs" (hypertension, hyperlipidemia, and hyperglycemia) being at high risk for myocardial infarction, the "four elderly" (retired leaders, professors, business owners, and senior citizens) are also at high risk. These two groups should actively treat their underlying diseases, such as controlling blood pressure, blood lipids, and blood sugar, paying attention to diet and exercise, and maintaining a healthy weight. They should be particularly vigilant during the "devil's time" from midnight to waking up. Therefore, experts suggest that those with high-risk factors for myocardial infarction drink a glass of water before bed and observe the "three three-minute intervals" between sleep and waking: lie quietly in bed for three minutes after waking; sit quietly in bed for three minutes after getting up; and rest for three minutes after getting out of bed before moving around. These "three three-minute intervals" help the body gradually adapt to the transition from rest to activity, which helps prevent acute myocardial infarction.