Angina pectoris is one of the forms of ischemic heart disease (CHD), occurs with pain in the chest, is caused by ischemia (a decrease in blood supply to any part of the myocardium due to a violation of arterial blood supply), the cause of which is atherosclerosis. Distinguish: stable angina pectoris (with indication of functional classes, coronary syndrome X), unstable (first-emerging, progressive, postinfarction), vasospastic (variant / Prinzmetal).
ECG criteria for angina pectoris
How does angina pectoris manifest on the ECG and with what you can see it.
The main way to diagnose this disorder is the electrocardiographic method with further decoding of the electrocardiogram.
| View | ECG signs of angina |
|---|---|
| Stable exertional angina | ST depression is more than 1 mm, less often its rise in the abduction from the wall of the left ventricle in the corresponding zone and a decrease in the reciprocal leads. Negative or positive and high T. |
| Unstable | Since this type belongs to acute coronary syndrome, the changes will be as follows: ST depression of more than 1 mm in two or more leads and negative T, which is shaped like an isosceles triangle. It is possible that short-term episodes of bundle branch blockade occur. |
| Vasospastic | The rise of ST with a transition to high T. Sometimes the expansion of the QRS, the increase in R, Q is similar to pathological. The appearance of atrioventricular blockade and atrial fibrillation. Changes last no more than 5-20 minutes. |
Advanced Angina Tests Using ECG
There are cases in which changes in the ECG for angina pectoris are not convincing enough, and this complicates the diagnosis. Then they resort to using additional research methods. These include Holter ECG monitoring (HM).
With HM on the ECG, a displacement of the ST segment of various severity and length is observed, which is characteristic of stable angina pectoris, unstable and Prinzmetal. The first is characterized by a decrease in ST, which slowly reaches its maximum, and then disappears after the termination of the load.
Often, exercise tests are used to diagnose coronary heart disease and, in particular, angina itself.
Let's take a look at some of them.
Bicycle ergometry (VEM)
Frequent attacks of angina pectoris are indications for this diagnostic manipulation.
Contraindications:
- heart failure ІІ B and ІІІ;
- frequent attacks of angina pectoris, their intensification in the last week;
- dissecting aortic aneurysm;
- respiratory failure;
- acute thrombophlebitis;
- thromboembolism;
- acute infectious diseases.
Sample preparation:
- spend two hours after eating;
- per day stop taking nitrates, calcium antagonists, potassium preparations, anabolic steroids, hormones;
- beta-blockers are canceled in three days;
- when seizures appear, "Nitroglycerin" is used;
- the reception of cardiac glycosides is stopped in three to seven days.
Description of the VEM technique:
- the examination is carried out after measuring blood pressure and registering an electrocardiogram at rest and determining the existing deviation from the norm;
- perform after a test with hyperventilation;
- use a stepwise intermittent technique;
- start from 25 W (5 minutes), with each next step, the load is increased by 100%.
Criteria for stopping the sample in case of ischemic heart disease and angina pectoris:
- ECG changes - horizontal or trough-like displacement of the ST segment by 1 mm or more than 2 mm with a sharply positive test;
- an increase in the QX / QT ratio by more than 50% (X-place on the isoline of the beginning of the T wave);
- the onset of symptoms of angina pectoris (chest pain), which occurs in 54-83% of people.
An example of a photo of a VEM sample
Thallium myocardial scintigraphy during physical activity
The method is based on the property of a substance to accumulate in direct proportion to the magnitude of the regional blood flow. Indications - dubious, or not brought to the appearance of diagnostic criteria for VEM. The occurrence of an accumulation defect at low load indicates dynamic ischemia.
Technetium myocardial scintigraphy during physical activity
Sample sensitivity and evaluation criteria are the same as in the previous one. The peculiarity is that an image of the left ventricle is obtained and its ejection fraction is determined.
Stress echocardiography
Combines VEM and echocardiography. Determines changes in a limited area of the heart muscle. Positive test criteria: maximum ejection fraction (EF) ≤ 35%; an increase in EF by less than 5%; manifestation of a violation of local contractility.
Conclusions
Angina pectoris is a serious disease that is important to identify in time, as it progresses rapidly and leads to myocardial infarction. ECG is considered the main diagnostic method. Thanks to him, in addition to ischemic changes, others are also determined that directly affect the course of this disease (hypertrophy of the left ventricle and atrium, atrioventricular blockade, various rhythm disturbances). But in doubtful cases, the doctor prescribes additional examinations for the patient. They are available today and are safe for the patient.
