Stress tests in cardiology practice in the conditions of the Lipetsk Regional Clinical Hospital.

DYNAMIC MYOCARDIAL SCINTIGRAPHY WITH LOAD

The purpose of myocardial scintigraphy is to study the microcirculation of the myocardium, its functional reserve in conditions of insufficient perfusion (blood passing through the myocardium) in patients with coronary artery disease (CHD), to determine the functional significance of coronary artery stenosis, tactics and prognosis of treatment.

Indications for stress EchoCG and stress scintigraphy are similar. The advantage of stress echocardiography over myocardial scintigraphy is higher specificity, the possibility of a more accurate study of the anatomy and function of the heart, higher availability and lower cost, as well as the absence of radiation. These methods, being more expensive in comparison with a trial with physical activity, are of great importance in the examination of patients with a low probability of having coronary artery disease, especially women, with ambiguous ECG results with exercise, when choosing an artery for myocardial revascularization (restoration of blood flow) and assessing ischemia after revascularization.

Contraindications to the study are the same as with the treadmill test. The significant weight of the patient (over 130 kg) is a limitation for performing the study in a gamma camera. In addition, the introduction of a radiopharmaceutical is contraindicated during pregnancy, breast-feeding.

Myocardial scintigraphy with technetril is carried out according to a two-day protocol: first, the study is performed at rest, then with a load.

The first stage is a study at rest, a radioactive substance is injected intravenously into the patient in combination with a special drug that can be quickly distributed through the myocardium (radiopharmaceutical). The Lipetsk Regional Clinical Hospital uses technetril for dynamic myocardial scintigraphy with a load. The substance will accumulate only in the area of the heart muscle where there is a good metabolism. Technically, myocardial scintigraphy is performed using a gamma camera in the patient's back position. With the help of a gamma camera, radiation is recorded, which is subsequently analyzed by a doctor. A defect in the accumulation of matter in the heart muscle may indicate the presence of a scar or a section of a viable myocardium with impaired blood supply. For clarification, myocardial scintigraphy with a load is shown.

The second stage is the study of the myocardium with physical activity (on a treadmill treadmill). The study is carried out on an empty stomach. It is necessary to cancel beta-blockers 48-72 hours, nitrates 24 hours before the study (on the recommendation of a cardiologist). The last meal should be at least 4 hours before the study. It is recommended not to consume caffeinated foods, refrain from drinking alcohol, smoking.

Blood pressure and ECG are monitored in order to timely detect ischemia and cardiac arrhythmias. The load is determined by the doctor conducting the study. The load stops when a certain heart rate is reached (depending on the patient's age) or when complaints or ECG and blood pressure parameters appear that do not allow the load to continue further.

At the peak of the load, a radiopharmaceutical is injected into the vein. After that, the patient returns to the treadmill and the load continues for another 1 minute.

The radiopharmaceutical is administered at maximum load levels when the patient has signs of myocardial ischemia. The radiopharmaceutical enters the bloodstream, circulates through the body and is absorbed by the myocardium.

After performing physical activity, the patient is asked to take fatty foods (for example, sour cream) for physiological emptying of the gallbladder and further transit through the intestine in order to reduce the background activity of the gastrointestinal tract and to avoid its imposition on the myocardium.

Repeated examination in the gamma chamber is carried out 60 minutes after the introduction of the radiopharmaceutical. Then its distribution in the heart muscle is analyzed.

At the end of the myocardial scintigraphy procedure, the patient is given recommendations for copious drinking (1.5-2 liters per day) and the exclusion of close contact with pregnant women and children for one day according to the requirements of radiation safety.

The absence of significant violations of myocardial perfusion according to load scintigraphy indicates a good prognosis even with proven coronary artery disease. The detection of significant perfusion disorders in patients with coronary artery disease indicates an unfavorable prognosis and serves as a good reason for coronary angiography with subsequent resolution of the issue of surgical myocardial revascularization.

Prepared:

• Head of the Department of Functional Diagnostics Natalia Viktorovna Zaikina
• Doctor of the Department of Functional Diagnostics Litvinenko Svetlana Aleksandrovna