Myocardial infarction: symptoms
Last reviewed: 23.04.2024
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Symptoms of myocardial infarction
Symptoms of myocardial infarction to some extent depend on the severity, localization of the obstruction of the artery and have a high variability. With the exception of cases of extensive heart attack, determining the prevalence of ischemia only on the basis of clinical manifestations presents difficulties.
After acute damage, various complications may develop. They usually consist of electrical dysfunction (for example, conduction disorders, arrhythmias), myocardial dysfunction (heart failure, interventricular septum or ventricular wall rupture, ventricular aneurysm, pseudoaneurysm, cardiogenic shock) or valve dysfunction (typically the appearance of mitral regurgitation). Electrical dysfunction can be significant in any form of myocardial infarction, while the development of myocardial dysfunction usually requires a violation of blood supply to large areas of the myocardium. Other complications of myocardial infarction include transient ischemia, parietal thrombosis, pericarditis and postinfarction syndrome (Dressler's syndrome).
Unstable angina
Clinical manifestations are the same as in angina pectoris, except that pain or discomfort in unstable angina is usually more intense, persist longer, are caused by less physical exertion, arise spontaneously at rest (like resting angina), have a progressive course (perhaps any combination of these features).
Myocardial infarction without STW segment elevation with its elevation
The manifestations of HSTMM and STMM are the same. In a few days or weeks before the acute episode, two-thirds of the patients experience prodromal signs, including unstable or increasing angina pectoris, lack of air and fatigue. Usually the first sign of a heart attack is a deep intense sensation with localization behind the sternum, described as pain or pressure, often radiating to the back, jaw, left arm, right arm, shoulders or all of these areas. The pain is similar to that of angina pectoris, but usually more intense and prolonged; more often accompanied by shortness of breath, profuse perspiration, nausea and vomiting; only a little and only temporarily decreases after taking nitroglycerin or at rest. However, the discomfort can be moderately expressed. Approximately 20% of cases of acute myocardial infarction are marked by a low-symptom course (either the so-called asymptomatic or the patient has vaguer sensations that he does not perceive as a disease), more often this pattern develops in diabetic patients. Some patients experience syncope. Often patients describe discomfort as dyspepsia, especially for the reason that spontaneous reduction in symptoms may inadvertently coincide with heartburn or the use of antacid drugs. More often atypical variants of discomfort arise in women. Elderly can complain more often of dyspnoea than with ischemic pain in the chest. In severe ischemic episodes, patients often experience severe pain, a sense of anxiety. Perhaps the emergence of nausea and vomiting, especially with lower myocardial infarction. Perhaps the predominance of dyspnea and weakness due to lack of left ventricle, pulmonary edema, shock, or severe arrhythmia.
The skin may be pale, cold to the touch and damp. Possible central cyanosis or acrocyanosis. Pulse may be threadlike, AD - changeable, although many patients initially have some increase in blood pressure due to pain.
Cardiac tones are usually somewhat muffled, almost always there is IV heart tone. There may be mild systolic murmur at the tip (reflecting the appearance of dysfunction of the papillary muscles). The pericardial friction noise and other more intense noises indicated at the first examination indicate a pre-existing heart disease or another diagnosis. The detected pericardial friction noise within a few hours after an acute episode similar to myocardial infarction is indicative of acute pericarditis more than of myocardial infarction. However, pericardial friction noise, usually short-term, often appears on the 2-3rd day after STHM. Pain in the palpation of the chest wall is noted in about 15% of patients.
With myocardial infarction of the right ventricle, the symptoms include increased right ventricular filling pressure, swelling of the cervical veins (often with the appearance of the Kussmaul symptom), bleaching of the pulmonary fields and arterial hypotension.
Classification of myocardial infarction
Classification of myocardial infarction is based on changes in ECG data and the presence or absence of markers of myocardial damage in the blood. The separation of myocardial infarction by HSTHM and IT is useful, because these conditions have different prognosis and treatment.
Unstable angina (acute coronary insufficiency, pre-infarction angina, intermediate syndrome) is defined as meeting the following criteria.
- Angina of rest, lasting more than 20 min.
- The first occurrence of angina pectoris (at least III functional class according to the classification of the Canadian Cardiovascular Society).
- Increase in angina: previously diagnosed angina with increased frequency of attacks, increasing their severity and duration, occurrence at a lower load (for example, an increase in one functional class and more or at least III functional class).
With unstable angina, ECG data may also change (segment decline, its rise or inversion of the tooth), however, these changes are transient. Of the markers of myocardial damage, there is no increase in the activity of CKK, but a slight increase in the content of troponin I is possible. Unstable angina is clinically unstable and can be a prelude to myocardial infarction, arrhythmias, or (more rarely) sudden death.
Myocardial infarction without segment elevation (HSTHM, subendocardial myocardial infarction) - myocardial necrosis (proven by markers of myocardial damage in the blood) without acute segment elevation and the appearance of a pathological tooth on an electrocardiogram. There may be segment depression, tooth inversion, or both.
Myocardial infarction with segment elevation (STMM, transmural myocardial infarction) - myocardial necrosis with changes in ECG data in the form of segment elevation, which does not return quickly to the isoline after taking nitroglycerin, or with the appearance of a complete blockade of the left branch of the bundle. Pathological teeth of O. May appear.
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