(1) Increased markers of myocardial necrosis:
① Myoglobin increased within 2 hours after onset, reached its peak within12 hours, and returned to normal within 24 ~ 48h hours.
② Troponin I(cTnI) or T(cTnT) increased at 3-4 hours after onset, with cTnI reaching its peak at 1 1-24 hours, and returning to normal at 7- 10 days, and cTnT reaching its peak at 24-48 hours,1-.
③ CK-MB isoenzyme of creatine kinase increased within 4 hours after onset, 16 ~ 24 hours reached the peak, and returned to normal in 3 ~ 4 days.
Creatine kinase (CK), L- aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) began to increase at 6 ~ 65 hours and 438+00 hours after the onset of AMI, and reached the peak at 65 hours, 438+02h hours, 24 hours and 2 ~ 3 days respectively. It returned to normal in 3 ~ 4d days, 3 ~ 6d days and 1 ~ 2 weeks respectively.
(2) White blood cell count: After 24 ~ 48h, white blood cells can increase to (10 ~ 20) × 109/L, neutrophils increase, eosinophils decrease or disappear.
(3) ESR: accelerated, lasting 1 ~ 3 weeks.
(4) Others: serum myosin light chain or heavy chain and serum free fatty acid are all increased, and the latter is obviously increased, which is prone to serious arrhythmia. In addition, due to stress reaction, blood sugar can be increased and glucose tolerance decreased, and it will return to normal in 2 ~ 3 weeks.
2. Electrocardiogram ECG of myocardial infarction has progressive and characteristic changes, which is of great diagnostic significance for diagnosing and estimating the location, scope and evolution of the disease.
(1) characteristic changes: ECG characteristics of patients with ST-segment elevation myocardial infarction are as follows:
① waveform of necrotic area.
Deep and wide Q waves (pathological Q waves) appeared in the leads facing transmural necrotic myocardium.
② waveform of damage area.
The lead facing around the necrotic area shows the ST segment with the arch back raised upward.
③ waveform of ischemic area. T-wave inversion is displayed on the lead facing the periphery of the injured area. However, the leads far away from the myocardial infarction area have the opposite changes, that is, the R wave increases, the ST segment decreases, and the T wave increases vertically.
There are two types of ECG in patients with non-ST-segment elevation myocardial infarction:
① There is no pathological Q wave, with general ST segment depression ≥ 1mm, but the ST segment of lead aVR (sometimes V 1 lead) is elevated, or the symmetric T wave is inverted into subendocardial myocardial infarction.
② No pathological Q wave or ST segment changes, only T wave inversion changes.
(2) Dynamic evolution of typical electrocardiogram: ST-segment elevation myocardial infarction,
① There may be no abnormality within a few hours after the onset, or there may be an abnormally high T wave and asymmetry of limbs, and then there will be an oblique rise of ST segment, which is connected with the towering T wave, which is a hyperacute change.
② After several hours, the ST segment of the lead facing the infarction area increased obviously, and the arch back was connected with the T wave in a unidirectional curve, while the R wave weakened or disappeared. The lead of the dorsal infarct area showed an increase in R wave and a decrease in ST segment, and the Q wave appeared within several hours to 2 days, which was an acute change.
③ From a few days to two weeks after the onset, the ST segment in the lead facing the infarct area gradually returned to the baseline level, and the T wave flattened or obviously inverted, while the T wave in the lead facing away from the infarct area increased, which was a subacute change.
④ From several weeks to several months after onset, T wave can be inverted V-shaped, with symmetrical limbs and sharp trough, which is a chronic change. 70% ~ 80% of pathological Q wave exists permanently, while T wave may recover within several months to several years.
Non-ST segment elevation myocardial infarction:
①ST segment is generally depressed (except aVR and sometimes V 1 lead), and then T wave is negative first and then positive, or inverted symmetry deepens, but Q wave never appears, and the changes of ST segment and T wave recover after several days or weeks, or even exist for a long time.
② The change of T wave recovered within 65438 0 ~ 6 months. Multiple focal myocardial infarction may not have typical ECG manifestations; Or healthy myocardium has small island ECG changes. When combined with Cambodian branch block, especially left bundle branch block, ECG may not reflect the manifestations of acute myocardial infarction. When acute myocardial infarction occurs again in the original site, the ECG performance is not typical.
(3) ECG localization diagnosis of infarction site: Clinical data show that myocardial infarction located in inferior wall, anterior septum and limited anterior wall is the most common. The location and range of ST-segment elevation myocardial infarction can be judged according to the leads with characteristic changes (Table 4- 1).
Table 4-4- 1 ST-segment elevation myocardial infarction ECG localization diagnosis
Conductor ÷ Front spacing ÷ Limited front wall ÷ Front side wall ÷ Wide front wall ÷ Lower wall
① Lower partition wall, lower side wall and high side wall
(2) [] is the back wall
③
v 1〔ここ+〕ここここ+〕
V2ここ+ここここ+ここ
v3ここ+ここ+ここ+ここ+ここ
v4〔こここ+〕
V5〔こここ+ここ+〔ここ+〕
V6】ここここ+ここここ+
V7ででででで+ででででで+ででで
V8 [Hibika, Hibika and Hibika]+
Automatic voltage regulation (abbreviation for automatic voltage regulation)
aVLででででで+ででで-でで-でで-で
aVF〔こここ-〕こ-〔ここ-〕+ここ+〕
Ⅰ〖〗〖〗 〖〗+〖〗 〖〗-〖〗-〖〗-〖〗+
Ⅱ〖〗〖〗-〖〗-〖〗-〖〗+〖〗+〖〗+〖〗-
Ⅲ〖〗〖〗-〖〗-〖〗-〖〗+〖〗+〖〗+〖〗-
① Diaphragm surface: Right ventricular myocardial infarction is not easy to be diagnosed by ECG, but sT segment elevation in lead cR4R or V4R can be used as an index of inferior myocardial infarction extending to the right ventricle;
② There may be some changes at the height of leads V5, V6 and V7 1 ~ 2 rib;
③ R wave enhancement in V1,V2 and V3 leads. Similarly, during anterior wall infarction, V 1 and V2 lead R waves also increase "+"to be positive, indicating that the typical Q wave, ST segment elevation and T wave change "-"are negative, indicating that the main QRS wave is upward, ST segment is downward, and T wave is opposite to "+".
3. Single photon emission tomography (sPEcT) is the most commonly used radionuclide examination. Using 99mmTc myocardial perfusion imaging, the whole process of ventricular relaxation → contraction → relaxation can be obtained, and observing the wall motion and left ventricular ejection fraction, the range, location and degree of ischemia is helpful to judge ventricular function, wall motion disorder after infarction and ventricular aneurysm. If positron emission computed tomography is used, it may be better to observe the metabolism of myocardium and judge the survival of myocardium.
4. Echocardiography section and M-mode echocardiography are also helpful to understand ventricular wall motion and left ventricular function, and to diagnose ventricular aneurysm and papillary muscle dysfunction.
5. Selective coronary angiography needs to consider the treatment of thrombolytic drugs in coronary artery, or when various interventional treatments are needed, selective coronary angiography can be performed first to make clear the lesions and formulate treatment plans.