Electrocardiogram acute myocardial infarction is myocardial necrosis caused by acute and persistent ischemic occlusion of the coronary artery. In clinical practice, there is often severe and persistent pain behind the sternum that cannot be completely relieved by rest and nitrate drugs. It is accompanied by an increase in serum myocardial necrosis markers and progressive electrocardiogram changes, which can lead to arrhythmia, shock, or heart failure. The condition is critical, and sudden death can occur at any time, endangering life. In recent years, the incidence rate of myocardial infarction has been increasing, with at least 500000 new cases occurring every year and at least 2 million current cases.
Electrocardiogram plays an irreplaceable role in the diagnosis of acute myocardial infarction. When chest pain occurs, the first test to be done is an electrocardiogram, which is the first line of defense against myocardial infarction and plays a significant warning role in clinical practice. The diagnostic value of electrocardiogram for myocardial infarction mainly lies in clarifying diagnosis, localization, determining scope, estimating the evolution and prognosis of the disease.
The depolarization and repolarization of the atria and ventricles of the heart, as well as the conduction of electrocardiogram, form P waves, QRS waves, ST segments, T waves, and Q waves on the electrocardiogram. These waveforms can provide a lot of information, one of which is to help diagnose acute myocardial infarction.
The definitive diagnosis of acute myocardial infarction can be determined by ST segment elevation, wide and deep pathological Q waves, and T wave inversion. Coronary artery occlusion leads to myocardial ischemia, and if ischemia is not corrected, myocardial damage will occur. If left untreated, myocardial necrosis will occur. Ischemia, injury, and necrosis have different manifestations on electrocardiogram, making the electrocardiogram of myocardial infarction patients show a dynamic change process. Ischemia is mainly characterized by T wave changes on electrocardiogram, myocardial injury is characterized by ST segment changes on electrocardiogram, and myocardial necrosis is manifested as pathological Q waves on electrocardiogram. The dynamic changes of T waves, ST segments, and Q waves help diagnose acute myocardial infarction.
Electrocardiogram also plays an important role in the localization of acute myocardial infarction. The coronary artery is divided into the left coronary artery and the right coronary artery, and the left coronary artery is further divided into the anterior descending branch and the circumflex branch. Generally speaking, the anterior wall, anterior septum, some high side walls, and a small portion of the lower wall are supplied by the anterior descending coronary artery, and in rare cases, the anterior descending artery can also supply blood to the posterior septum; The high lateral wall, most of the posterior wall, and some of the lower wall are supplied by the circumflex coronary artery. The right coronary artery supplies blood to the right ventricle, most of the left ventricular inferior wall, and some of the left ventricular posterior wall. The ST segment elevation in the corresponding lead of the electrocardiogram can help detect which wall of the heart has infarction. For example, anterior septal myocardial infarction (V1-V3 leads); Anterior wall myocardial infarction (V3-V5 leads); Anterior wall myocardial infarction (V5-V7 leads); Widespread anterior myocardial infarction (V1-V5, lead I aVL）； High sidewall myocardial infarction (lead I aVL）； Inferior myocardial infarction (II, III, aVF leads); Posterior wall myocardial infarction (leads V7-V9).
Electrocardiogram is of great significance for the localization diagnosis and determination of the extent of myocardial infarction. Not only can it help doctors quickly locate and diagnose, but it also prompts doctors to perform myocardial reperfusion therapy as soon as possible. It can also prompt doctors to make targeted preliminary judgments on the diseased blood vessels related to infarction and carry out targeted interventional treatment.
In addition, electrocardiogram can also help patients with acute myocardial infarction to determine the treatment effect of thrombolysis. The effectiveness of thrombolysis is often judged by whether the patient's chest pain is relieved, changes in the peak of myocardial enzymes, and whether the ST segment of the electrocardiogram has decreased and the degree of decrease. The changes in ST segment after thrombolysis can help determine whether thrombolysis helps with recanalization and guide whether further intervention therapy is needed.
Electrocardiogram plays a crucial role in the diagnosis and treatment of acute myocardial infarction.