Myocardial ischemia, as a pathophysiological condition, is the insufficiency of blood and oxygen supply to the heart caused by coronary artery stenosis, spasm or embolism.High risk groups includecoronary heart disease、ArrhythmiaAnd other diseases.If it develops intoischemic heart diseaseStage: according to the severity of coronary heart disease, it can be divided into concealed type orAsymptomatic coronary heart diseaseAngina pectoris, myocardial infarction, ischemic cardiomyopathy and sudden death.
The clinical symptoms of myocardial ischemia are discomfort and pain in the precordial region, and severe myocardial ischemia can be accompanied byArrhythmiaandCardiac insufficiency, causing various accompanying symptoms.
For the treatment of myocardial ischemia, the main goal is to improve the myocardial blood supply and reduce the myocardial oxygen consumption, usually taking medication.For myocardial ischemia of different causes, if the condition is serious, interventional treatment or surgical treatment can be carried out.The prevention of myocardial ischemia is mainly to avoid the risk factors related to myocardial ischemia, such as cold, excessive exercise, etc., improve bad living habits, and actively control the progress of coronary heart disease and related chronic diseases.
Early recognition and timely treatment of myocardial ischemia are extremely important, especially when it is found that physical examination or ECG examination suspect myocardial ischemia, chest pain and other typical symptoms are accompanieddyspnea、Consciousness obstacleIn case of systemic symptoms, they should go to the hospital immediately.
The root cause of myocardial ischemia is that the blood and oxygen supply of the coronary artery to the myocardium cannot meet the oxygen demand of the myocardium.
The specific causes can be divided into two categories: coronary artery insufficiency and abnormal increase of myocardial oxygen consumption (blood), which is generally dominated by insufficient blood supply.Common diseases are coronary heart disease, syndrome X, coronary artery spasm, myocardial bridge, arrhythmia, etc.
Emotional excitement, heavy physical activity, smoking, drinking and other factors often act as incentives for myocardial ischemia.
Pathogenesis
The myocardium is supplied by the coronary artery, which has a strong compensatory capacity. When the oxygen demand of the heart increases, the coronary artery can expand, thus increasing the blood supply of the myocardium several times.
When the coronary artery is diseased, not only the above compensatory mechanism may not work normally, but also the coronary artery may be narrowed or even occluded, resulting in a sharp reduction of myocardial blood supply, which is one of the most important mechanisms of myocardial ischemia.
On the other hand, if you have some arrhythmias or heavy physical activity burden, your heart will beat faster and your myocardial oxygen consumption will increase. At this time, if the coronary artery cannot provide enough blood for the myocardial oxygen supply, myocardial ischemia will also occur.
In addition, because the blood supply of the coronary artery mainly occurs in the diastole of the heart, too fast heartbeat will reduce the proportion of diastole in the whole heartbeat cycle, thus reducing the coronary artery blood flow.
The full name is coronary atherosclerotic heart disease, which is the most common cause of myocardial ischemia.
Hypertension, diabetes, hyperlipidemia, inflammation and other disease factors, smoking, drinking, sedentary, staying up late, psychological stress and other bad habits may lead to systemic blood vessels (includingcoronary artery）Endothelium is damaged, which promotes the occurrence and development of atherosclerosis, and then leads to stenosis or even occlusion of vascular lumen, leading to myocardial ischemia.
It is a disease that can produce symptoms of myocardial ischemia. ECG can observe the manifestations of myocardial ischemia, but coronary angiography can not observe the corresponding coronary artery disease, and the cause is not clear.
Angina vasospasm
Angina vasospasm, also known as variant angina pectoris, often presents myocardial ischemia symptoms without obvious inducement. Different from syndrome X, coronary angiography can observe temporary coronary spasm and stenosis when angina pectoris occurs.
At present, the disease is believed to be caused by abnormal vascular regulation function rather than coronary artery disease. This is because most of the patients with this disease are young and lack of other risk factors for coronary heart disease in addition to smoking, and do not show pathological changes of coronary heart disease.
Myocardial bridge
The coronary artery is usually in the connective tissue under the epicardium. If a segment shuttles in the myocardium, this segment of myocardial fiber can be called the myocardial bridge. When the heart contracts, it can compress this segment of coronary artery, thus causing myocardial ischemia.
It can be seen from various tachyarrhythmias. If coronary artery disease is not combined at the same time, the myocardial ischemia caused by it is temporary. When the heartbeat returns to normal, the myocardial ischemia will be relieved.
Predisposing factors
Myocardial ischemia can be induced by any factor that causes increased cardiac burden, increased myocardial oxygen consumption, or sudden coronary artery stenosis and decreased blood supply.
Common inducing factors include:
Smoking: including active smoking and second-hand smoke. Long term exposure will damage the inner wall of arteries, leading to vasospasm.
Diabetes: Both type 1 and type 2 diabetes can promote the occurrence and development of atherosclerosis.
Hypertension: It can accelerate atherosclerosis and cause damage to arteries and blood vessels.
Hyperlipidemia: Cholesterol is the main deposit that can make coronary artery narrow.
Obesity: Obesity is related to a variety of cardiovascular diseases.
Others: drinking, improper drug taking, physical activity, mood fluctuation, satiety, cold, etc.
symptom
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The clinical manifestations of patients with myocardial ischemia vary significantly from individual to individual, and some patients may have no obvious symptoms. The symptomatic patients with myocardial ischemia mainly show discomfort and pain in the precordial area, while the symptoms of precordial area will have different changes in different degrees of myocardial ischemia.
Severe myocardial ischemia is often accompanied by arrhythmia andCardiac insufficiency, showing various accompanying symptoms of the heart and the whole body.
Typical symptoms
The most typical symptom of myocardial ischemia is discomfort and pain in the precordial area during exercise, which can be relieved automatically after the exercise stops.
The precordial discomfort can be specifically manifested as the patient feels stuffy, tight, etc. The pain is squeezing pain, so it is called angina pectoris, sometimes accompanied by a sense of fear of dying.
In addition to the precordial area, the pain may also affect the upper jaw, lower upper abdomen, and the left side can include the left shoulder, the left upper limb and the broad range of the little thumb side.
In addition to the above symptoms, the patient may also have nausea, vomiting, sweating, fatigue and weakness.
In myocardial ischemia, another part is calledAsymptomatic myocardial ischemia，PathogenesisUnknown.In such patients, when myocardial ischemia is very serious, or even myocardial infarction has occurred, the patients themselves may not feel obvious discomfort.
It should be noted that the precordial discomfort and pain caused by myocardial ischemia caused by different diseases will be different.
coronary heart disease
At first（Stable angina pectoris）Angina pectoris can be rapidly induced by the above-mentioned inducements, and then gradually aggravated. After removing the inducements, it can relieve itself within 3-5 minutes. The use of nitroglycerin and other coronary artery dilating drugs can also rapidly relieve the symptoms.
When the coronary artery disease is further aggravated（Unstable angina pectoris）The performance of angina pectoris will also make some progress. Angina pectoris can occur at rest without obvious incentives, with more severe pain and longer duration, up to about 10-20 minutes.
When the coronary artery is completely occluded due to atherosclerosis, causing myocardial ischemia and necrosis (myocardial infarction), the degree of angina pectoris will be more serious than before, and the duration can also be extended to hours to days, even if takingglyceryl trinitrateAnd can't relieve the pain.
Angina vasospasm
Angina pectoris symptom has no obvious inducement, and generally occurs from midnight to 8am.The symptoms of patients can be relieved by themselves, and may also occur arrhythmia and syncope. If coronary artery spasm lasts for a long time, myocardial infarction may also occur.
Accompanying symptoms
Mild myocardial ischemia generally has no accompanying symptoms, but with the aggravation of ischemia, there will be arrhythmia, cardiac insufficiency and other manifestations, which can be manifested as cardiovascular system, digestive system and systemic symptoms.
Arrhythmia related symptoms
It can be seen in a variety of myocardial ischemia diseases, among which myocardial infarction and ischemic cardiomyopathy are the most common, and may have no obvious manifestations, or the manifestations areChest tightness、palpitationAnd may be accompanied by general fatigue, dizziness, syncope and other symptoms.
It is commonly seen in acute inferior myocardial infarction, which is characterized by frequent nausea, vomiting and epigastric pain.
Other systemic symptoms
fever
Seen in myocardial infarction, it is a reaction caused by the absorption of necrotic substances. It generally does not exceed 39 ℃, and it usually occurs 1~2 days after the occurrence of infarction, lasting about 1 week.
shock
Mainly by large areamiocardial infarction, caused by a sharp decrease in cardiac output, which can be manifested as lower blood pressure, irritability, pale complexion, wet and cold skin, fast pulse, sweating, apathy and other symptoms.
Medical treatment
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The heart is an important organ to maintain life. If you cannot relax your vigilance in case of the following conditions, you should go to the hospital immediately to find out the condition:
When the patient is suspected of myocardial ischemia by physical examination or ECG examination;
When there are uncomfortable symptoms near the heart, such as chest pain;
In addition to heart discomfort, if accompanied by other system symptoms, systemic symptoms, especially dyspnea and disturbance of consciousness, it is likely to indicate a serious condition.
Visiting department
Myocardial ischemia caused by whatever reason is generally diagnosed and treated in cardiovascular medicine. If coronary artery bypass grafting surgery is required after assessment, it can be transferred to cardiac surgery.
Diagnostic process
The doctor may ask the following questions to get a preliminary understanding of the condition, and the patient can be prepared to answer the questions in advance:
What's wrong with you?How did they change?How long does it last each time?Is it self relieving?How long will it be relieved?
What diseases have been diagnosed before?
Do you usually smoke?How much?Do you drink alcohol?How about the quantity?
Is there any other chronic cardiovascular disease, such as hypertension, diabetes, hyperlipidemia?
What medicine do you usually take?
Do family members have heart disease?
The doctor will make a preliminary judgment on the condition through symptoms and physical examination, preliminarily determine the degree and location of myocardial ischemia through electrocardiogram, treadmill exercise test, load radionuclide myocardial scanning, etc., judge whether there is myocardial infarction and the possible time of infarction through myocardial enzymes, and through CCTA (coronary CT angiography)Or coronary angiography to determine whether the coronary artery has serious stenosis, lesion location and nature.
So far, whether myocardial ischemia exists can generally be determined, and the cause of myocardial ischemia can also be identified.
Relevant inspection
Physician physical examination
Physical examination of myocardial ischemia mainly includes percussion and auscultation of chest, especially heart, and measurement of blood pressurepulse。
Physical examination is only used to find cardiac enlargement, cardiac dysfunction and some arrhythmias. It is not possible to judge whether myocardial ischemia is caused by physical examination alone.
It is mainly used to check whether there is anemia.
Blood fat, blood sugar
hyperglycemiaIt can damage blood vessels and then cause atherosclerosis, which is an important risk factor of coronary heart disease;Excessive blood lipids (LDL-C, VLDL-C, TC, TG, etc.) can deposit on the injured vascular wall and participate in the formation of atherosclerosis;It is also an important risk factor for coronary heart disease.
Doctors can assess the risk of coronary heart disease through these two indicators.
Myocardial enzymes and troponin
The components in these myocardial cells will enter the blood when myocardial injury occurs, making the test results abnormally high.
Doctors use these indicators to determine whether myocardial ischemia exists myocardial infarction.
Common indexes with high myocardial specificity include cTnI, cTnT, CK-MB, etc.
thyroid function
Sometimes patients may have palpitations, chest tightness and other symptoms that cannot be explained by cardiac organic diseases, andTachycardiaIf you need to check your A skill, you should rule outHyperthyroidismCardiac abnormalities caused by.
Common indicators include FTthree、FTfour、TTthree、TTfourAnd TSH secreted by pituitary gland to regulate thyroid function.
Imaging examination
ultrasonic
Doctors can observe whether there are abnormal changes in heart structure and function through color B-ultrasound examination of the heart, and can determine whether there is cardiac enlargement, myocardial hypertrophy, and valvular disease. They can also evaluate heart function and predict disease prognosis by observing the blood flow of the heart.
In case of myocardial infarction,Colour SonographySegmental cardiac dyskinesia may be found at the infarct site.
CT
After the injection of contrast agent, the advanced multi-slice spiral CT can be used to scan the coronary artery of the heart to find the stenosis of the coronary artery, but the limitation is that once calcification occurs, it will seriously affect the accuracy of the diagnosis of vascular lesions.
Therefore, the main significance of CT examination of coronary artery is to observeNegative results, coronary artery disease can be basically excluded.
Coronary angiography
An invasive examination.It is necessary to puncture the peripheral blood vessels (wrist or thigh root), extend a catheter through the puncture site to the coronary artery entrance, create a shadow agent, and then observe whether there is coronary artery stenosis through the digital subtraction X-ray machine, which is the gold standard for diagnosis of coronary artery disease.
In addition to assisting in diagnosis, this examination can also directly carry out treatment, such as using a balloon to open a stenotic coronary artery, using a embolic catheter to extract thrombus in acute myocardial infarction, and the most well-known stent placement at the stenotic site, to achieve the purpose of improving heart blood supply.
However, coronary angiography is expensive and invasive, so its application is limited.
Special inspection
electrocardiogram
It can observe the changes of electrical activity of the heart, and preliminarily locate the location of abnormal electrical activity. It is non-invasive, easy to operate, and has good repeatability. It is particularly important for the preliminary diagnosis of myocardial ischemia and what other heart problems are associated with it, especially as an observation of the changes in the condition.
ECG examinationIncluding ordinary 12 lead ECG, 18 lead ECG and 24-hour dynamic ECG:
The 12 lead ECG is a well-known method of connecting the chest and limbs;
Compared with 12 leads, 18 leads increase the observation of the side and back of the chest in the same form as 12 leads;
Holter is a mobile device that allows the patient to carry on his back and stick a line on his body to continuously record the changes of cardiac electrical activity for 24 hours, so that he can find abnormal conditions and pathological changes that are incidental and difficult to be detected by ordinary electrocardiogram, and can make statistics on various abnormal electrical activities in a day.
differential diagnosis
Myocardial ischemia mainly needs to be differentiated from various diseases with chest pain as the main manifestation, as well as different causes of myocardial ischemia.
Differentiation from other diseases causing chest pain
Aortic dissection
Pain is intense, persistent and unrelenting, often accompanied by a history of hypertension;The dissection involving the opening of coronary artery will lead to acute occlusion of coronary artery. There are clinical manifestations of acute myocardial infarction, such as ST segment elevation in ECG.Color Doppler echocardiography or CTA of aorta can make a definite diagnosis.
Intercostal neuralgia and costochondritis
The nature of pain is tingling or burning, and it is persistent. Cough, breathing and other actions can aggravate the pain due to pulling on the lesion, which makes it easy to distinguish it from myocardial ischemia.
Cardiac neurosis
The nature of pain is mostly temporary tingling or persistent dull pain.Chest painThe onset time is more after fatigue than at the time of fatigue, and if physical activity continues, chest pain often does not increase, or even may decrease.It is easy to differentiate from myocardial ischemia.
The manifestations of coronary artery disease with different degrees were different from those of myocardial enzyme examination;Myocardial ischemia caused by other non coronary factors can also be easily identified by medical history and imaging findings.
treatment
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The treatment principles of myocardial ischemia caused by different causes are very different, but the overall treatment idea is the same, that is, to improve myocardial blood supply and reduce myocardial oxygen consumption.
The main treatment of myocardial ischemia is drug therapy, and patients with severe condition can be treated by interventional therapy or surgery.
Acute treatment
The purpose of treatment in acute phase is to quickly relieve the ischemic state, and different causes will have different treatment measures.
Use drugs that reduce heart load (such as various antihypertensive drugs), and drugs that slow heart rate and reduce myocardial contractility (such as beta receptor blockers, calcium channel blockers) to reduce heart oxygen consumption.
For more severe myocardial ischemia, a load dose of aspirin and clopidogrel can also be used at the onset.
General treatment
It includes two situations: attack and peacetime.
During seizure
Stop activities and stay in bed;
Family members should actively appease patients and try to eliminate their nervous and excited emotions;
Keep ventilation, if possible, give oxygen to patients to improve myocardial ischemia and hypoxia.
peacetime
Actively control the risk factors that cause myocardial ischemia, such as controlling blood pressure, blood sugar, blood lipids, smoking cessation, and alcohol restriction.
Moderate exercise can improve cardiovascular health to a certain extent.
Family members help patients maintain a peaceful and happy mood.
If there are diseases that may aggravate myocardial ischemia, they should be actively treated, such as all infectious diseases, fever caused by various reasons, hyperthyroidism, anemia, hypotension, cardiac insufficiency, respiratory failure, and various fast arrhythmia and serious slow arrhythmia.
medication
There are many causes of myocardial ischemia, involving many kinds of drugs. Patients must be treated with drugs under the guidance of doctors.
Anti myocardial ischemia drugs
Nitrates
Nitroglycerin belongs to this kind of medicine. Nitroglycerin takes effect quickly and is often used during myocardial ischemia attack to rapidly expand coronary artery and increase myocardial blood supply.
Nitroglycerin can be administered not only sublingually, but also by intravenous injection (including drip).
Nitroglycerin is prone to drug tolerance, which will reduce the effect. Therefore, it cannot be used continuously for a long time. It needs to expand coronary artery continuously. It needs to use other long-acting types of nitrates, such as isosorbide dinitrate and isosorbide mononitrate.
The most common adverse reactions of nitrates are headache and skin flushing, which usually do not affect drug use.Occasionally, hypotension can be seen.
Beta blocker
It can play the role of anti myocardial ischemia by reducing cardiac contractility and heart rate, and reducing myocardial oxygen consumption.
Beta blockers can reduce the incidence of myocardial infarction and play an important role in improving the short-term and long-term prognosis of coronary heart disease.
Beta blockers are forbidden to be used in patients with bronchial asthma and severe atrioventricular block.
Calcium channel blocker
Although different from the pharmacological mechanism of beta blockers, they can also reduce the cardiac contractility, and some can also reduce the heart rate, effectively improve myocardial ischemia and relieve angina symptoms.
According to clinical trial observation, this kind of medicine alone cannot prevent the occurrence of acute myocardial infarction, nor can it reduce the mortality, so it is the second choice medicine when treating persistent myocardial ischemia, but it is the first choice medicine when treating myocardial ischemia caused by vasospasm (variant angina pectoris).
The common adverse reactions were hypotension and edema.
Diltiazem, verapamil and other types that can reduce heart rate are prohibited for patients with cardiac insufficiency, sinus node dysfunction, and atrioventricular block.
Other commonly used drugs
Lipid lowering drugs
The abnormal increase of low density lipoprotein cholesterol and very low density lipoprotein cholesterol is closely related to atherosclerosis. Reducing cholesterol can reduce the occurrence of coronary heart disease and delay the progression of atherosclerosis. Common drugs include fluvastatin, atorvastatin, rosuvastatin, etc.
antiplatelet drugs
It can prevent thrombosis in coronary artery, prevent or delay the progress of coronary heart disease.It mainly includes aspirin, clopidogrel, prasugrel, tigrilol, etc.
It can be used for the treatment of more serious unstable angina pectoris and non ST elevation myocardial infarction, and can also assist in thrombolysis and interventional treatment.Commonly used include low molecular weight heparin, bivalirudin, etc.
surgical treatment
Medical Interventional Therapy
Percutaneous coronary intervention (PCI) is now the most commonly used method to treat serious coronary artery disease. The method is to cut the superficial artery (usually the artery at the base of the wrist or thigh), send the catheter through the artery to the coronary artery, and open the coronary artery through various ways. It is less traumatic and has a definite effect.
The main PCI technologies are as follows.
Percutaneous coronary balloon dilatation
That is PTCA.The operation method is to send the evacuated air balloon to the diseased blood vessel through the catheter, inflate the balloon, expand the balloon, and stretch the narrowed blood vessel to achieve the purpose of treating myocardial ischemia, and sometimes continue to be assisted by other interventional treatment.
However, percutaneous transluminal coronary angioplasty (PTCA) alone for the treatment of coronary artery stenosis, not only has a high rate of restenosis, but also has the risk of coronary artery dissection tear or acute occlusion.
Coronary artery stenting
Through the catheter, the metal stent is sent to the diseased blood vessel and stretched to keep the blood vessel unblocked.Most patients need to be implanted with stents after the aforementioned interventional treatment to ensure the long-term patency of the coronary artery.
As the early stent is a pure metal, as a foreign body, it can cause vascular endothelial hyperplasia, resulting in restenosis.However, drug-eluting stents, which are widely used in recent years, have drug coatings on their surfaces to inhibit intimal hyperplasia, and the 1-year restenosis rate is below 10%.
surgical operation
When the medical treatment of angina pectoris is ineffective or the coronary artery disease is serious, surgical treatment is required, namely coronary artery bypass grafting, commonly known as "bypass".
The surgery first intercepts the blood vessels in other parts of the body, and then opens the chest cavity, anastomoses the proximal end of the transplanted blood vessels to the wall of the ascending aorta, and the distal end to the normal vascular segment at the distal end of the stenosis site of the coronary artery disease, replacing the diseased blood vessels, so as to achieve coronary artery recanalization and restore myocardial blood supply.
If the transplanted blood vessel becomes restenosis, it can also be rebranded or PCI to extend the life of the patient and improve the quality of life.
TCM treatment
The TCM treatment of the disease is not supported by evidence-based medical evidence, but some TCM treatment methods or drugs can alleviate symptoms, so it is recommended to go to regular medical institutions and treat under the guidance of doctors.
Other treatments
Myocardial ischemia rarely exists alone, and is often associated with a variety of cardiovascular diseases.Therefore, in addition to the above measures, treatment may also include controlling blood sugar, blood pressure, and treatmentArrhythmia、Cardiac insufficiencyThe treatment of these diseases is also based on drugs.
Frontier treatment
At present, drug eluting balloons are more and more widely used in clinical practice, which can avoid the permanent presence of foreign bodies in the body (stent implantation), and can be selectively used in suitable patients under the guidance of doctors.
prognosis
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The prognosis of myocardial ischemia depends on the type and degree of the disease causing myocardial ischemia, and the survival period is difficult to estimate because of a large number of unknown factors.
If myocardial ischemia is caused by simple tachycardia, there will be no significant impact on health.
If it is myocardial ischemia caused by coronary heart disease, the situation will be more complex.If the coronary artery disease is mild, it can survive for a long time after standard treatment;If there has been myocardial infarction, or ischemic cardiomyopathy due to long-term myocardial ischemia, the survival period will be significantly shortened, and the mortality of myocardial infarction itself is relatively high;If ischemic cardiomyopathy or myocardial infarction is serious and causes chronic cardiac insufficiency, the prognosis is poor.
If myocardial ischemia is caused by other non coronary artery disease, the prognosis is generally good, but there is also a risk of sudden exacerbation and myocardial infarction.
recovery
In the first 3-6 weeks after discharge from hospital after myocardial infarction treatment, physical activity should be gradually increased. It is recommended that patients carry out moderate physical activity, such as walking, gymnastics, shadowboxing, etc.This is beneficial to reduce the risk of cardiovascular events and improve the health of patients.
If after the above reasonable rehabilitation exercise, there is still good cardiac function 6 weeks after myocardial infarction, it indicates that the patient's life can basically return to normal.
complication
miocardial infarction
Severe myocardial ischemia, which lasts for a long time, can lead to myocardial necrosis, which can be either a serious type of coronary heart disease or caused by other coronary artery diseases.
The mortality rate of myocardial infarction is high, and it will cause a series of follow-up problems, such as those with large infarct size, which can lead toHeart failure、Cardiogenic shock。
Those with deeper infarcts may cause the thinned ventricular wall to bulge under the influence of blood pressure, called ventricular aneurysm, or even appearCardiac rupture；Infarction leads to dysfunction or rupture of papillary muscles, which may lead to mitral insufficiency;Thromboembolism of lung or other organs and tissues is easy to occur after infarction;After myocardial infarction, recurrent pericarditis, pleurisy and pneumonia may also occur, which is related to the allergic reaction of human body to necrotic tissue.
Ischemic cardiomyopathy
The disease caused by degeneration of myocardium under long-term ischemia and hypoxia is characterized by the rigidity and expansion of the heart, which can be accompanied by various arrhythmias and heart failure.The 5-year mortality rate was 50%~84%.
