Vol.12, No 3, 2005 pp. 135 - 139
UC 616.12-008.331.1
THE FIVE YEARS PREDICTIVE VALUE OF QTc
INTERVAL
AND QTc INTERVAL DISPERSION IN HYPERTENSIVE PATIENTS
WITH LEFT VENTRICULAR HYPERTROPHY
Dragan B. Đorđević, Branko Lović, Stevan Ilić, Marina Deljanin Ilić,
Ivan Tasić
Institute for Prevention, Treatment and
Rehabilitation of Rheumatic and Cardiovascular Diseases, "Niška Banja",
Niška Banja
E-mail: nikaca@bankerinter.net
Summary. The aim of the paper is a study of QTc
interval, QTcp
interval (interval from Q wave to the peak of T wave), Tp-Tendc
interval (interval
from the peak of T wave to the end of T wave) and their dispersion with
respect
to the five-year predictive value of these intervals in patients with
essential
arterial hypertension and left ventricular hypertrophy. A total of 90
patients
(56 males and 34 females) were examined, average age 55.2 ± 8.3 years,
who
suffered from essential arterial hypertension and left ventricular
hypertrophy.
The control group comprised 35 healthy subjects (20 males and 15
females),
average age 54.5 ± 7.1 years. The average left ventricular mass index
was 171.9
± 32.4 g/m2 in hypertensive patients and
102.4 ± 13.3 g/m2
in healthy controls. The QTc interval and QTcp interval (interval from
Q wave
to the peak of T
wave) were longer in the left ventricular hypertrophy group than in
healthy
controls (p < 0.01) in the baseline electrocardiogram.
During
exercise testing, QTc interval shortened in the hypertensive group
(p < 0.001)
but was unchanged in controls. QTc dispersion (p < 0.001)
and QTcp
(p < 0.001) had higher values in the hypertensive group
before and
after exercise testing, compared to healthy subjects. Fifteen (16.7%)
patients
had cardiovascular and cerebrovascular adverse events during the
five-year
follow-up. In the group of hypertensive patients with left ventricular
hypertrophy, cardiovascular and cerebrovascular adverse events were
more
frequent in those patients who had higher values for the left
ventricular mass,
left ventricular mass index, wall thickness, and QTc dispersion before
and
after exercise testing, as well as a wider QRS complex, and slower rise
of
heart rate during exercise testing. Independent predictors of bad
outcome were
greater posterior wall thickness and QTc dispersion after exercise
testing.
Intervals and their dispersion as 'Q wave-peak of T wave' and 'peak of
T
wave-end of T wave' were less useful than QTc interval and QTc
dispersion
according to the prognosis.
Key words: Arterial hypertension, left ventricular hypertrophy,
QTc interval, QTc dispersion, prognosis
PETOGODIŠNJA PROGNOSTIČKA VREDNOST QTc
INTERVALA
I DISPERZIJE QTc INTERVALA KOD HIPERTENZIVNIH PACIJENATA
SA HIPERTROFIJOM MIOKARDA LEVE KOMORE
Kratak sadržaj: Cilj je bio ispitati QTc interval, QTcp interval
(interval od Q zupca do vrha T talasa), Tp-Tendc interval (interval od
vrha T talasa do kraja T talasa) i njihove disperzije u odnosu na
petogodišnju prognozu ovih intervala kod parijenata sa esencijalnom
arterijskom hipertrenzijom i hipertrofijom leve komore.
U studiji je ispitano 90 pacijenata (56 muškaraca i 34 žene), prosečne
starosti 55,2 ± 8,3 godine, sa esencijalnom arterijskom hipertenzijom i
hipertrofijom miokarda leve komore. U kontrolnoj grupi bilo je 35
zdravih osoba (20 muškaraca i 15 žena), prosečne starosti 54,5 ± 7,1
godina. Prosečan indeks mase leve komore bio je 171.9 ± 32.4 g/m2
kod hipertenzivnih pacijenata i 102,4 ± 13,3 g/m2
kod zdravih osoba. QTc interval i QTc disperzija (interval od Q zupca
do vrha T talasa) su bili veći u grupi sa hipertrofijom leve komore u
odnosu na zdrave ispitanike (p < 0,01) na bazalnom
elektrokardiogramu. U toku testa opterećenja QTc interval se skratio u
hipertenzivnoj grupi (p < 0,001) i ostao nepromenjen u grupi zdravih
ispitanika. QTc disperzija (p < 0,001) i QTcp disperzija (p <
0,001) su bile veće u hipertenzivnoj grupi pre i nakon testa fizičkim
opterećenjem. Neželjeni kardiovaskularni i cerebrovaskularni događaji
su se desili kod 15 (16,7%) bolesnika u toku petogodišnjeg praćenja.
Neželjeni kardiovaskularni i cerebrovaskularni događaji, kod
hipertenzivnih pacijenata sa hipertrofijom miokarda leve komore, su
bili češći kod pacijenata sa većom masom leve komore, većim indeksom
mase leve komore, debljim zidovima leve komore, većom QTc disperzijom
pre i nakon testa fizičkim opterećenjem, širim QRS kompleksom i manjim
porastom frekvence srca tokom testa fizičkim opterećenjem. Nezavisni
prognostički markeri loše prognoze bili su veća debljina zadnjeg zida i
veća QTc disperzija nakon testa fizičkim opterećenjem. Intervali i
njihove disperzije, kao što su Q zubac - vrh T talasa i vrh T talasa -
kraj T talasa, bili su manje značajni od QTc intervala i QTc disperzije
u prognostičkom smislu.
Ključne reči: Arterijska hipertenzija, hipertrofija leve komore,
QTc interval, QTc disperzija, prognoza
