RU2078534C1 - Method for determining presence of functional reserve of myocardium in patients affected with acute myocardial infarction - Google Patents

Abstract

FIELD: medicine, cardiology. SUBSTANCE: following procedure is recommended: measurements are made of beat volume of left ventricle of patient's heart and of diastolic pressure in pulmonary artery in initial condition and after diastolic pressure rise by 3 mm Hg caused by administering controllable volume of dextrane into patient's pulmonary artery aperture. Calculations are made to determine functional reserve factor of patient's myocardium using following formula:

, wherein BV₁ is beat volume of left ventricle in initial condition, BV₂ is beat volume of left ventricle after administering liquid and diastolic pressure rise by 3 mm Hg in pulmonary artery, D $\genfrac{}{}{0ex}{}{\text{1}}{\text{d}}$ is diastolic pressure value in pulmonary artery in initial condition, D $\genfrac{}{}{0ex}{}{\text{2}}{\text{d}}$ is diastolic pressure value in pulmonary artery after administering liquid, and V is administered liquid volume. Cardiologist proceeds upon assumption that value of myocardium's functional reserve factor equal to, or greater than 1.0 serves as evidence of presence of functional reserve in patients suffering from acute myocardial infarction. Proposed method can be used at very early staves of developing myocardial infarction; it permits to timely establish presence or absence of functional reserve in patient's myocardium, to introduce appropriate adjustments into medicamentous therapy and to obtain reliable information permitting to return patients affected with acute myocardial infarction to active life in due time. EFFECT: improved efficiency of the method.

Description

 The invention relates to medicine, namely to cardiology, and can be used to determine the presence of a functional reserve of the heart muscle in patients with acute myocardial infarction.

 A known method of determining the functional reserve of the heart in patients with acute myocardial infarction, carried out using volumetric fluid loading and direct measurement of diastolic pressure in the pulmonary artery and stroke volume of the left heart. After measuring the diastolic pressure in the pulmonary artery and the stroke volume of the left ventricle in the initial state, through a catheter inserted into the pulmonary artery, multiple injections of liquid are carried out in portions of 100 to 200 ml until the level of diastolic pressure in the pulmonary artery exceeds the initial value by 6 mm Hg After each fluid injection, the stroke volume of the left ventricle and the diastolic pressure in the pulmonary artery are measured, the so-called functional curves of the heart are constructed and, analyzing them, the reserve capabilities of the heart are evaluated.

 The method involves the introduction into the pulmonary artery of a significant (up to 1.0 L or more) volume of fluid with increasing pressure in the pulmonary artery reaching a critical level, which is a significant danger for a patient with acute myocardial infarction with the threat of fatal complications, in particular, pulmonary edema. The method also does not provide a quantitative criterion for assessing the reserve of the heart muscle, which greatly complicates the interpretation of the data.

 The method allows to determine the increase in the quantitative criterion of the reserve of the heart muscle in patients with myocardial infarction.

где УO₁ ударный объем левого желудочка в исходном состоянии,
УO₂ ударный объем левого желудочка после введения жидкости и повышения диастолического давления в легочной артерии на 3 мм рт.ст.The goal is carried out by measuring the stroke volume of the left ventricle of the heart and diastolic pressure in the pulmonary artery in the initial state, by injecting fluid (dextran) into the pulmonary artery to achieve a level of diastolic pressure in the pulmonary artery that exceeds the original by 3 mm Hg. measuring the volume of injected fluid, which caused an increase in diastolic pressure by 3 mm Hg the stroke volume of the left ventricle and the calculation of the coefficient of the functional reserve of the heart muscle, taking into account the increase in diastolic pressure in the pulmonary artery, the magnitude of the change in the stroke volume of the left ventricle of the heart and the volume of fluid injected by the expression:

where UO ₁ stroke volume of the left ventricle in its original state,
UO ₂ stroke volume of the left ventricle after fluid injection and increased diastolic pressure in the pulmonary artery by 3 mm Hg

D $\genfrac{}{}{0ex}{}{\text{one}}{\text{d}}$ diastolic pressure in the pulmonary artery in the initial state,
D $\genfrac{}{}{0ex}{}{\text{2}}{\text{D}}$ diastolic pressure in the pulmonary artery after the introduction of fluid,
V is the volume of fluid injected.

The value of the coefficient of the functional reserve of the heart muscle (K _f ) determines the presence of a functional reserve of the heart muscle in patients with acute myocardial infarction, while a coefficient equal to or greater than 1.0 indicates the presence of a sufficient functional reserve of the heart muscle, and the coefficient is less than 0, 75 on the absence of a functional reserve of the heart muscle.

 The method is as follows.

где УO₁ ударный объем левого желудочка сердца в исходном состоянии,
УO₂ ударный объем левого желудочка после введения декстрана и повышения диастолического давления в легочной артерии на 3 мм рт.ст.Pulmonary artery catheterization is carried out under X-ray control using a Kurnan catheter, the location of the catheter is controlled by a pressure curve. The pressure in the pulmonary artery is measured using a Statham P 23 OB strain gauge and recorded on a Mingograph-81 polygraph. The accuracy of the pressure measurement is ± 0.05%. Measurement and continuous recording of the stroke volume is carried out using tetrapolar rheography, the measurement accuracy is ± 5%
Measure the stroke volume of the left ventricle and diastolic pressure in the pulmonary artery in the initial state. Using an automatic syringe, dextran is introduced through the catheter into the pulmonary artery cavity while continuously measuring the diastolic pressure in the pulmonary artery. Upon reaching a diastolic pressure level exceeding the original by 3 mm Hg carry out the measurement of the volume of injected fluid and the measurement of stroke volume of the left ventricle. Then determine the coefficient of the functional reserve of the heart muscle (K _f ) by the expression:

where UO ₁ stroke volume of the left ventricle of the heart in the initial state,
UO ₂ shock volume of the left ventricle after administration of dextran and increase in diastolic pressure in the pulmonary artery by 3 mm Hg

D $\genfrac{}{}{0ex}{}{\text{one}}{\text{d}}$ diastolic pressure in the pulmonary artery in the initial state,
D $\genfrac{}{}{0ex}{}{\text{2}}{\text{d}}$ diastolic pressure in the pulmonary artery after administration of dextran,
V is the volume of dextran administered, which caused an increase in diastolic pressure in the pulmonary artery by 3 mm Hg.

The magnitude of the coefficient of functional reserve (K _f ) is judged on the presence of a functional reserve of the heart muscle in patients with acute myocardial infarction. Moreover, the value of K _f equal to or greater than 1.0 indicates the presence of a sufficient functional reserve of the heart muscle, and a value of less than 0.75 indicates the absence of a functional reserve of the heart muscle.

 Based on the analysis of clinical data from a survey of 100 patients, taking into account the calculated discriminatory value, the value of the coefficient of the functional reserve of the heart muscle was determined, which indicates the presence of a functional reservoir of the heart muscle in patients with acute myocardial infarction, equal to or greater than 1.0, and the value of the coefficient of the functional reserve, indicating the absence functional reserve of the heart muscle in patients with acute myocardial infarction is less than 0.75.

Величина К_ф, равная 1,25 (превышает 1,0) и описанная реакция с положительной динамикой ударного объема левого желудочка в ответ на нагрузку объемом свидетельствуют о наличии функционального резерва сердечной мышцы у данного больного и реализации его при проведении нагрузочной пробы. Последующее течение заболевания гладкое, без осложнений. Через 14 дней больной переведен в отделение реабилитации.Example 1. Patient M.G.K. 36 years old, weight 87 kg, height 178 cm. Delivered with complaints of sharp pains in the heart region that appeared 6 hours before admission to the clinic. Clinical and electrocardiographic data and laboratory results indicated the development of acute myocardial infarction of the anterior septal, apical region of the left ventricle of the heart. Immediately after admission, pulmonary artery catheterization was performed under X-ray control using a Kurnan catheter. The catheter is connected to a Statham P 23 OB strain gauge to measure pulmonary pressure. Measurement of stroke volume of the left ventricle was carried out using tetrapolar rheography. Registration of the measured parameters was carried out on the Mingograph 81. Initial data: heart rate 72 beats. in minutes, mean arterial pressure 111 mm RT. Art. diastolic pressure in the pulmonary artery 26 mm RT. Art. stroke volume of the left ventricle 66 ml. Through a catheter using an automatic syringe, the introduction of dextran, at the time of increasing diastolic pressure in the pulmonary artery by 3 mm RT. (pressure was 29 mm Hg) the volume of dextran injected was 0.25 L. The measurement of stroke volume of the left ventricle, the value of which was 81 ml. The heart rate did not practically change (74 beats per minute), the average blood pressure was 118 mm Hg. Art. Thus, the introduction of 0.25 L of dextran into the pulmonary artery led to an increase in pressure in the pulmonary artery by 3 mmHg. Art. compared with baseline and stroke volume of 15 ml. The coefficient of the functional reserve of the heart muscle is calculated:

The value of K _f equal to 1.25 (exceeds 1.0) and the described reaction with positive dynamics of the stroke volume of the left ventricle in response to the load volume indicate the presence of a functional reserve of the heart muscle in this patient and its implementation during the exercise test. The subsequent course of the disease is smooth, without complications. After 14 days, the patient was transferred to the rehabilitation department.

Отмеченные особенности реакции левого желудочка сердца на объемную нагрузку у данного больного и величина коэффициента функционального резерва 0,065 (менее 0,75) свидетельствуют об отсутствии функционального резерва сердечной мышцы у больного острым инфарктом миокарда. Несмотря на проводимую интенсивную терапию, на 2-е сутки пребывания больного в стационаре у больного появились клинические признаки недостаточности кровообращения по левожелудочковому типу, которые под влиянием терапии исчезли лишь на 9-е сутки. Дальнейшее течение средней тяжести. Больной переведен в отделение реабилитации на 28 день от начала заболевания. Таким образом, коэффициент функционального резерва сердечной мышцы (К_ф 0,065), определенный в первый день пребывания больного в стационаре, свидетельствовал об отсутствии компенсаторного резерва сердечной мышцы, что обусловило тяжелое течение заболевания с развитием недостаточности кровообращения и поздний перевод больного в отделение реабилитации.Example 2. Patient G.L.I., 45 years old, weight 90 kg, height 180 cm. Delivered with complaints of sharp pains in the heart that appeared 8 hours before admission. After a clinical, electrocardiographic study, taking into account laboratory data, acute transmural myocardial infarction of the anterior septal, apical region of the left ventricle of the heart was diagnosed. The course of the disease before the examination is uncomplicated, there are no signs of circulatory failure. Pulmonary artery catheterization and initial hemodynamic parameters were measured: heart rate - 57 beats. in minutes, the average blood pressure of 90 mm RT. Art. diastolic pressure in the pulmonary artery 27 mm RT. Art. stroke volume of the left ventricle - 52 ml. Through a catheter inserted into the pulmonary artery, the introduction of dextran is started. After the introduction of 0.05 L of dextran, an increase in diastolic pressure in the pulmonary artery by 3 mm Hg was recorded. Art. compared with the initial level (30 mm RT. Art.) The measurement of stroke volume of the left ventricle of the heart - 53 ml. Heart rate 57 beats. in minutes, the average blood pressure of 90 mm RT. Art. Thus, the introduction of a small (0.05 L) volume of dextran led to an increase in diastolic pressure by 3 mm RT. Art. however, there was no positive dynamics of the stroke volume of the left ventricle of the heart in response to a volume load. The coefficient of the functional reserve of the heart muscle is calculated:

The noted features of the reaction of the left ventricle of the heart to the volume load in this patient and the value of the functional reserve coefficient of 0.065 (less than 0.75) indicate the absence of a functional reserve of the heart muscle in a patient with acute myocardial infarction. Despite intensive therapy, on the 2nd day of the patient’s stay in the hospital, the patient showed clinical signs of circulatory failure of the left ventricular type, which, under the influence of therapy, disappeared only on the 9th day. Further course of moderate severity. The patient was transferred to the rehabilitation department on the 28th day from the onset of the disease. Thus, the coefficient of the functional reserve of the heart muscle (K _f 0.065), determined on the first day of the patient’s stay in the hospital, indicated the absence of a compensatory reserve of the heart muscle, which caused a severe course of the disease with the development of circulatory failure and a late transfer of the patient to the rehabilitation department.

 Thus, the proposed method for determining the presence of a functional reserve of the heart muscle in patients with acute myocardial infarction increases the safety of the method by reducing the volume of fluid introduced into the pulmonary artery to 0.05 L 0.45 L (compared with 1.0 1.2 L or more used in the prototype method) and by reducing the increase in diastolic pressure in the pulmonary artery in response to a volume load of up to 3 mm RT. Art. compared with 6 mm RT. Art. when using the prototype method, which significantly reduces the risk of fatal complications, in particular, pulmonary edema in patients with acute myocardial infarction with an initially elevated level of diastolic pressure in the pulmonary artery (these complications did not occur during the examination using the proposed method in any of 100 cases).

 Using the method for determining the presence of a functional reserve of the heart muscle in patients with acute myocardial infarction is possible at the very early stages of the development of acute myocardial infarction, it allows timely detection of the presence or absence of a functional reserve of the heart muscle in patients with this type of cardiac pathology, and it makes it possible to reasonably choose the drug treatment based on the level functional reserve of the myocardium. The presence of a functional reserve may indicate a more favorable course of the disease and the possibility of early activation of patients with acute myocardial infarction.

Claims (1)

A method for determining the presence of a functional reserve of the heart muscle in patients with acute myocardial infarction, including the introduction of fluid into the pulmonary artery, measuring the diastolic pressure in it and the stroke volume of the left ventricle of the heart, characterized in that after measuring the diastolic pressure and stroke volume of the left ventricle, dextran is injected into the pulmonary artery to achieve a pressure increase of 3 mm Hg measure the stroke volume of the left ventricle and the volume of fluid injected, calculate the change in stroke volume, and the value of the coefficient K _{f the} functional reserve of the heart muscle is determined by the expression

where U. O ₁ stroke volume of the left ventricle in its original state;
U. O ₂ stroke volume of the left ventricle after fluid injection and increased diastolic pressure in the pulmonary artery by 3 mm Hg D $\genfrac{}{}{0ex}{}{\text{one}}{\text{d}}$ - diastolic pressure in the pulmonary artery in the initial state;
D $\genfrac{}{}{0ex}{}{\text{2}}{\text{d}}$ - diastolic pressure in the pulmonary artery after the introduction of fluid;
V is the volume of injected fluid,
and at K> 1, the presence of a functional reserve of the heart muscle in patients with acute myocardial infarction is determined.