Biomedical subjects

M Lechmanová

Publications and source records attributed to M Lechmanová.

3 recordsLinked to original sources

PubMed2002

Changes of the electrical heart field and hemodynamic parameters in the 34th to 40th weeks of pregnancy and after delivery.

We have studied changes of the electrical heart field resulting from the changed spatial position of the heart during the last period of pregnancy in healthy women. This was suggested to be a good model of electrocardiographic changes that could be found on patients suffering from obesity. The measured parameters of the electrical heart field were compared with hemodynamic parameters before and after delivery in the group of non-obese women with physiological pregnancy and in a group of healthy non-obese and non-pregnant women. Several significant changes of the electrical heart field were detected in the late pregnancy: increased heart rate, shortening of A-V conductance, prolongation of QT interval normalised for the heart rate and changes in the ventricular depolarisation and repolarisation patterns. Some of these changes are not fully restored in 4 days after delivery. Moreover, we have found an increased pump function of the left ventricle accompanied by decreased peripheral resistance in the group of pregnant women. Increased pump function was partially restored after delivery, peripheral resistance was not only restored, but it overshot to increased values. Persisting elevated heart rate with increased peripheral resistance suggested increased sympathetic activity after birth. Only some changes of electrical heart field could be explained by changed spatial arrangement of the chest organs during pregnancy and they must be considered in a complex consequence with changes in regulatory mechanisms.

Adult↗

PubMed2002

QT dispersion and T-loop morphology in late pregnancy and after delivery.

The aim of the study was to detect changes of both the QT dispersion and T-loop morphology resulting from the changed spatial position of the heart during pregnancy. Electrocardiographic and vectorcardiographic recordings were obtained from 37 healthy women 19-36 years old in the 36th to 40th week of physiological pregnancy and 2 to 6 days after delivery. The same recordings were obtained from 18 healthy women of the same age. The average QT dispersion (+/- S.D.) in normal subjects was significantly lower (34 +/- 12 ms) than in those in late pregnancy (73 +/- 18 ms) (P < 0.001). The average amplitude of T-loop (Ta) in women in late pregnancy was significantly (P < 0.001) smaller (532 +/- 98 microV) and the width of T-loop (Tw) was wider (21.24 +/- 11.48 deg) than in the control group (793 +/- 114 microV and 7.17 +/- 3.02 deg, respectively). The partial post-partum restoration of all parameters was not significant. In all groups, the QT dispersion was significantly correlated with Tw but not with Ta. According to these results we can conclude that the QT dispersion is an indirect reflection of the complete process of ventricular repolarization, reflected in the morphology of the T-loop.

Adult↗

PubMed2001

[QT interval dispersion].

Dispersion of QT intervals has been proposed as a measure of repolarization process inhomogeneity (and thus refractority inhomogeneity) of ventricular myocardium. Recently other possible explanation of this phenomenon has been intensively discussed. According to this concept QT dispersion is explained by different projections of the heart repolarization vector. Moreover, the reproducibility of the measurement of QT dispersion is rather low as it could be influenced both by intrinsic (e.g., amplitude of the T wave or U wave) and extrinsic (e.g. noise, amplitude and time parameters of recording) factors. Only markedly prolonged QT dispersion must be therefore interpreted as a sign of the abnormal course of the repolarization. Nevertheless, according to all mentioned facts the only serious interpretation of increased QT dispersion is that it reflects unspecific repolarization changes. More precious explanation is by then not possible (and it is disputable if it ever will be).

Animals↗