RU2088142C1 - Method to determine basic functional factors of left ventricle - Google Patents

Abstract

FIELD: medicine, cardiology, functional diagnostics. SUBSTANCE: method deals with estimating the duration of certain time intervals in one of the following electrocardiogram branches such as breast, standard and palate ones. Based on the data obtained and using mathematical formula the values of end-diastolic, end-systolic, minute and stroke volumes, average diastolic and systolic thickness of left ventricle wall and degree of muscular wall thickening are detected. EFFECT: higher efficiency and accuracy.

Description

 The invention relates to medicine, namely to the functional diagnosis of the cardiovascular system, and can be used to determine the main functional indicators of the left ventricle of the heart in order to obtain express information about the state of the heart muscle.

 Known non-invasive method of ultrasonic echocardiography (EchoCG), which allows to determine the final diastolic volume (BWW), final systolic volume (CSR), stroke volume (UO), ejection fraction (EF) of the left ventricle (LV) and minute volume (MO) of blood circulation [1 ] Despite the informational content of this method, its use in practice requires complex expensive equipment, a highly skilled operator and a considerable time (60 min) for one study [2] which excludes the possibility of obtaining express information.

 In addition, the use of the EchoCG method for determining the main functional parameters of the left ventricle of the heart may not be possible at all because of the individual anatomical features of the patient's chest, because it may not have a suitable “window” for the penetration of ultrasonic sensing.

 At the same time, the literature contains extensive factual material showing the close conjugation of the electrical and physiological parameters of the heart [3]. These data, as well as our studies, show that the transmission speed of the ECG signal through the LV conducting system and LV myocardium is practically constant. It follows that the transit time of the electrical impulse through the conducting system and myocardium is proportional to the size of the cavity and the thickness of the LV of the heart. This allows us to determine almost all the basic functional indicators of the first ventricle of the heart.

 The purpose of the invention is to obtain more accurate diagnostic express information about the main functional parameters of the left ventricle of the heart by processing data obtained using conventional electrocardiography (ECG) regardless of the severity of the patient's condition.

 The proposed method is simple in terms of hardware and software, non-invasive and non-invasive and allows you to get the basic functional parameters of the left ventricle of the heart with minimal time: KDO, KSO, UO, PV and MO, as well as determine the average diastolic and systolic wall thickness of the left ventricle and degree thickening of this wall in systole.

The closest to the achieved result is a non-invasive method for determining the volume-functional parameters of the left ventricle of the heart according to electrocardiography [4] However, the accuracy of the main LV indicators obtained using the mentioned method using only the t _QRS and t _RR intervals is insufficient to obtain a reliable diagnostic characteristic of the state of central hemodynamics .

The purpose of the invention is achieved by the fact that the cardiogram is recorded in reinforced IV or V thoracic leads, and if it is impossible to register them in the II standard lead (or lead A in the sky). The pulling speed should not be lower than 100 mm / s. In the absence of blockade of the bundle branch blocks and ventricular rhythm on the ECG, they are measured in one cardiac cycle: firstly, the duration of t _QRS signals from the beginning of the Q wave (along the upper edge of the PQ segment) to the end of the S wave (point J); secondly, the duration of the interval t _ST-T from the end of the tooth S to the end of the tooth T at the zero level (isoline); thirdly, the duration of the interval t _RS from the top of the R wave to the end of the S wave with an accuracy of no worse than 0.005 s; fourthly, with an accuracy of no worse than 0.01 s, measure the duration of the interval t _RR between the vertices of the R waves in adjacent cardiocycles.

 The following formulas for calculating the main functional parameters of the left ventricle of the heart by ECG are derived from a comparative analysis of the indicators obtained in this way with the data of X-ray contrast studies (kinoventriculography) of 80 patients using the Tridoros-Optimatic 1000 apparatus, as well as with the data of Exo-KG 286 patients using the MARC- 3 and MARC-500 (USA), including various load tests (orthostasis, antiorthostasis).

BWW, KSO, UO, MO and PV determined by the formulas:
BWW, ml 4879t _QRS 230t _RS 94t _ST-T + 12t _RR 192;
CSR, ml 3035t _QRS 1558t _RS 250t _ST-T + 1t _RR 84;
MO, l 148.4t _QRS 53t _RS + 16.3t _ST-T - 9.6t _RR 2.1;
UO, ml 1844t _QRS 748t _RS + 156t _ST-T + 11t _RR 108;
PV, -668t _QRS + 443t _RS + 137t _ST-T + 2.9t _RR + 62.5
The average thickness of the LV wall in diastole is determined by the formula:
h _d 22 • t _RS , see

The average thickness of the LV wall in systole is determined by the formula:
h _s h _d • T _{ST-T / t QRS} , see

The degree of thickening of the LV muscle wall in systole is determined by the formula:
SU (t _ST-T / t _QRS 1) • 100,
A study of the correlation between the main functional indicators of LV and various ECG time intervals shows that when determining BWW using four intervals, namely t _QRS , t _RS , t _ST-T and t _RR , compared to the method when only two intervals are used t _QRS and t _RR , the multiple regression coefficient r increases from 0.86 to 0.964, and the standard error SE decreases from 21.5 to 11.6 ml; when determining KCO, r rises from 0.82 to 0.958, and SE decreases from 15.9 to 8.2 ml; when determining the CR, r rises from 0.82 to 0.917, and SE decreases from 10.7 to 7.6 ml [5]
Sources of information
1. Mukharlyamov N. M. Belenkov Yu.N. Ultrasound diagnostics in cardiology. M. 1981

 2. Zaretsky V.V. Bobkov V.V. Olbinskaya L.N. Clinical echocardiography. M. 1979

 3. Orlov V.N. Guide to electrocardiography. M. 1983

 4. Degtyarev V.A. Orlov V.N. Nesvetov V.N. Evdokimova A.G. Ragozin V.N. Kiselev B.I. Auth. St. N 1692553 "Method for determining the functional state of the left ventricle of the heart", priority of July 22, 1991

 5. Voskresensky A. D. Multivariate statistical analysis of the connections of the volumetric-functional indicators of the heart with the complexes of the intervals of the electrocardiogram. NIMC Report 1992

Claims (1)

The method for determining the main functional parameters of the left ventricle of the heart, measuring the intervals t _{Q R S} and t _{R R} (c) in the IV or V thoracic or II leads or in the A lead in the Sky in the absence of ECG blockade of the legs of the bundle of His and ventricular rhythm, different the fact that in addition to measuring in one heart cycle the duration of the intervals t _{S T - T} and t _{R S} c and calculate the values of the final diastolic volume (BWW), ml, final systolic volume (CSR), ml, minute volume (MO), l, shock volume (UO), ml, ejection fraction (EF), medium the bottom diastolic wall thickness of the left ventricle (hd), cm, the average systolic wall thickness of the left ventricle (hS), cm, the degree of thickening of the muscle wall in systole (SU), according to the following formulas:
BWW 4879 t _{Q R S} 230 t _{R S} 94 t _{S T - T} + 12 t _{R R} 192;
KCO 3035 t _{Q R S} 1558 t _{R S} 250 t _{S T - T} + 1 t _{R R} 84;
MO 148.4 t _{Q R S} 53 t _{R S} + 16.3 t _{S T - T} 9.6 t _{R R} 2.1;
UO 1844 t _QRS 748 t _RS + 156 t _ST-T + 11 t _RR 108;
LW -668 t _{Q R S} + 443 t _{R S} + 137 t _{S T - T} + 2.9 t _{R R} + 62.5;
hd 22 t _{R S} ;
hs hd x (t _{S T - T} / t _{Q R S} - 1) • 100;
SU (t _{S T - T} / t _{Q R S} 1) • 100.