QT Dispersion and
T-Loop Morphology in Late Pregnancy and After
Delivery
M.
LECHMANOVÁ, O. KITTNAR, M. MLČEK, J.
SLAVÍČEK, A. DOHNALOVÁ, Š. HAVRÁNEK, J.
KOLAŘÍK, A. PAŘÍZEK1
Institute of Physiology and 1Department of
Obstetrics and Gynecology, First Faculty of
Medicine, Charles University, Prague, Czech
Republic
Received May 18, 2001
Accepted June 28, 2001
Summary
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 mV) and the width of T-loop (Tw) was
wider (21.24±11.48 deg) than in the control
group (793±114 mV 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..
Key
words
QT
dispersion ·
Electrocardigraphy ·
Vectorcardiography · T-loop
morphology · Pregnancy
Reprint
requests
O. Kittnar, Institute of Physiology, First
Faculty of Medicine, Charles University, Albertov
5, 128 00 Prague 2, Czech Republic. e-mail: okittnar@lf1.cuni.cz
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