Low-T3 Syndrome and
Signal-Averaged ECG in Hemodialyzed Patients
A. J. JAROSZYŃSKI1, A. GŁOWNIAK2,
B. CHRAPKO3, T. SODOLSKI2,
T. MAŁECKA1, T. WIDOMSKA-CZEKAJSKA2, A.
KSIĄŻEK1
Chair and Clinic of Nephrology1, Chair and Clinic of
Cardiology2, Department of Nuclear Medicine3,
Medical University of Lublin, Poland
Received February 26, 2004
Accepted November 25, 2004
On-line available January 10, 2005
Summary
The study was designed to evaluate the potential link between
low-T3 syndrome and signal-averaged ECG parameters (SAECG) in a
group of hemodialyzed patients (HD-pts). 52 selected HD-pts
(without relevant thyroid and cardiac diseases) were included.
SAECGs were performed postdialysis together with evaluating free
triiodothyronine (fT3), free thyroxine (fT4), reverse
triiodothyronine (rT3), thyroid stimulating hormone levels and
echocardiography. For each SAECG, QRS duration (QRSd),
root-mean-square voltage of the terminal 40 ms of the QRS
(RMS40), and low-amplitude signal duration (LAS40) were
measured. Abnormal SAECGs were found in 30.8 % of HD-pt. HD-pts
with decreased fT3 and increased rT3 values (low-T3 positive)
revealed higher QRSd and LAS40 values in comparison with low-T3
negative HD-pts (p=0.019, p<0.001 respectively). Low-T3 positive
HD-pts had lower RMS40 values than low-T3 negative patients
(p<0.001). The Pearson test showed significant correlations
between QRSd and fT3 (r=-0.592, p<0.001); QRSd and rT3 (r=0.562,
p<0.001); RMS40 and fT3 (r=0.432, p=0.009); RMS40 and rT3
(r=-0.325, p=0.025). On multivariate analysis, both fT3 and rT3
levels were found to be independent predictors of QRSd and RMS40
values. Our study showed that decreased fT3 and increased rT3
concentrations due to low-T3 syndrome influence SAECG parameters
in HD-pt.
Key words
Haemodialysis • Late ventricular potentials • SAECG • Low-T3
syndrome • Reverse triiodothyronine
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