Evaluation of Сontractile Activity of the Fetal Heart During Paroxysms of SVT and During Restoration of Sinus Rhythm During one Study

Objective. Evaluation of changes in the contractile function of the fetal heart against the background of a paroxysm of ventricular tachycardia, and to compare these data with the indicators of cardiac function during the restoration of a heart rhythm with a heart rate of less than 180 beats/min during one study.

Materials and Methods. The work was performed by the Federal State Budgetary Institution «NMITS AGP named after V.I. Kulakov» of the Ministry of Health of the Russian Federation. The study included 25 pregnant women gestating from 18 to 40 weeks with a paroxysmal form of supraventricular tachycardia, in whom the contractility of the fetal heart was assessed during one ultrasound examination against the background of LVT paroxysm and during sinus rhythm.

To assess the contractile function of the fetal heart, we used pulse dopplerometry of blood flow on AV valves and semilunar valves, M-mode, the Simpson method, and the Fetal HQ program, which were evaluated against the background of LVT paroxysm and after restoration of the sinus rhythm of the heart

The bulk of the statistical data processing was performed using the Stata/MP v program. 17.0 (StataCorp LLC, TX: 77845, USA, https://www.stata.com, 2021).

The results of our study determined the features of the fetal heart against the background of LVT paroxysm, which are expressed in the development of ventricular myocardial hypertension (an increase in the thickness of the ventricular walls and LVEF), a decrease in the ability of the heart to diastolic relaxation (a decrease in the diastolic size of the ventricles) and, as a result, a significant decrease in the contractile function of the fetal heart, which is manifested in a decrease in both transverse shortening of the myocardium (ventricular shortening fractions), and indicators of longitudinal shortening of the myocardium (decreased systolic excursion of the AV valves — TAPSE and MAPSE, longitudinal deformation of the ventricular walls — GLS, global longitudinal deformation of the ventricles – Free Wall Strain). Such changes in cardiac activity during prolonged and frequent paroxysms with the preservation of impaired diastolic function of the ventricles of the heart in the intercalary period lead to stagnation in a large circle of blood circulation and the formation of ascites and dropsy in the fetus, which in this sample of patients occurred in 32 % of cases.

Conclusion. This study demonstrated that against the background of LVT paroxysm, significant changes occur in the contractile function of the fetal heart, which lead to the formation of ineffective cardiac activity, resulting in decreased cardiac output, pronounced atrioventricular regurgitation and increased central venous pressure, which ultimately leads to dropsy, and in the future, in the absence of intrauterine treatment, fetal death may occur.

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