Context. Undifferentiated connective tissue dysplasia (UCTD) has negative impact on myocardial contractility and endothelial microvascular dysfunction and their frequent combination with cardiac arrhythmias suggests an unfavorable course of pregnancy and childbirth due to the formation of uteroplacental dysfunction. Objective. To reduce the incidence of obstetric complications associated with cardiovascular disorders in women with UCTD by including carnitine-arginine complex in the treatment program. Materials and methods. 58 pregnant women with diagnosed signs of UCTD, including mitral valve prolaps (MVP) with and without frequent extrasystoles, and 14 pregnant women of control group were examined. Metabolic support with of 4.2 g of L-arginine and 2.0 g of L-carnitine in the form of a solution for intravenous infusion once a day for 5 days were used for prenatal care of pregnant women with UCTD and prevention of obstetric complications in the experimental group. Results. There are violations of morpho-functional parameters of the heart with the development of moderate systolic-diastolic myocardial dysfunction and endothelial microvascular dysfunction in the initial state of pregnant women with MVP and extrasystolic arrhythmia against the background of UCTD. They were significantly more often diagnosed with miscarriage, late preeclampsia, placental dysfunction, birth defects, birth trauma, postpartum hemorrhage, etc. Echostructural abnormalities of the heart acted as predictors of arrhythmias, the presence of which was associated with more pronounced disorders of intracardiac hemodynamics. The results of a comprehensive study of the clinical and functional status of pregnant women with phenotypic signs of UCTD, MVP and extrasystolic arrhythmia suggest that in most cases they occur with moderate heart remodeling and significant endothelial dysfunction of the microvascular circulation, that was accompanied by significant deterioration of the obstetric situation. The use of standard medication by pregnant women did not significantly restore the incidence of arrhythmias, inotropic capacity of the myocardium and endothelial function of microvessels. Supraventricular and ventricular arrhythmias remained resistant to standard treatment, which justified the use of additional antiarrhythmic drugs. At the same time, there was a significant reduction in the incidence of arrhythmias in the group of patients with MVP and frequent ventricular or mixed extrasystoles – by 90.6 and 77.8 % respectively under the influence of complex drug treatment with the inclusion of L-arginine and L-carnitine. In the group of pregnant women with supraventricular arrhythmias, the antiarrhythmic effect was observed in only 37.5 % of patients, which justified the additional use of nebivolol hydrochloride at a dose of 2.5 mg/day. At the same time, such a comprehensive treatment in pregnant women with MVP and arrhythmia on the background of UCTD contributed to the restoration of the studied indicators of endothelial function of microvessels. Conclusions. In pregnant women with MVP and extrasystolic arrhythmia against the background of UCTD in the initial state there are violations of morpho-functional parameters of the heart with the development of moderate systolic-diastolic myocardial dysfunction and endothelial microvascular dysfunction, which are triggers of complicated pregnancy and childbirth. The inclusion of L-arginine and L-carnitine led to a significant improvement in the parameters of central cardiohemodynamics and restoration of endothelial function of microvessels and accompanied by a significant reduction of the incidence of extrasystolic arrhythmia and pregnancy complications.
