0041-1337/01/7209-1523/0 TRANSPLANTATION Vol. 72, 1523–1526, No. 9, November 15, 2001 Copyright © 2001 by Lippincott Williams & Wilkins, Inc. Printed in U.S.A. INCREASED QT DISPERSION IN HEMODIALYSIS PATIENTS IMPROVE AFTER RENAL TRANSPLANTATION: A PROSPECTIVE- CONTROLLED STUDY 1 ALAATTIN YıLDıZ, 2,4 VAKUR AKKAYA, 3 TUFAN TU ¨ KEK, 3 SEVGI S ¸ AHIN, 2 M. SU ¨ KRU ¨ SEVER, 2 SEMRA BOZFAKıOG ˘ LU, 2 AND FERRUH KORKUT 3 Istanbul School of Medicine, Department of Internal Medicine and Department of Cardiology, Division of Nephrology, Istanbul, Turkey Increased QT dispersion (QTd), predicting patients with risk of malignant arrhythmia, have recently been reported in hemodialysis patients (HDp). In this pro- spective study, we aimed to investigate changes in QTd and signal averaged-ECG (SAECG) in HDp after transplantation. Twenty-seven HDp (M/F:18/9, mean age 308 years) and 24 controls (M/F:14/10, mean age 336 years) were included. All QT parameters (QT- max, Qtmin, and QTd) were increased in HDp. QTmax and QTd started to decrease at the first month after transplantation. Percentage change in QTd at the third month was significantly correlated with percent- age change in LV mass index (r0.45, P0.04), serum calcium (r0.47, P0.02) and intact parathyroid hor- mone (r0.68, P0.01). In multivariate regression analysis, only percent chance in LV mass index was retained as significant. As for analysis of SAECG, 4 of the 23 (17%) HDp has abnormal late potentials which disappeared after transplantation. HDp with LV hy- pertrophy had higher filtered-QRS duration com- pared to patients without hypertrophy (11012 vs. 9711 msec, P0.01). It was concluded that increased QTd and presence of late potentials improved early after renal transplantation. These changes were mainly associated with the regression of the LV mass. INTRODUCTION Cardiovascular problems are major cause of mortality in patients with end stage renal disease. Fifty-six percent of the cardiovascular mortality in dialysis patients ascribed to car- diac arrest and arrhythmia (1). QT dispersion, reflecting inhomogeneity in ventricle repolarization, have been used for predicting patients with risk of malignant arrhythmia and sudden death (2). Recently, increased QT dispersion had been reported for hemodialysis patients (3, 4). In this pro- spective study, we aimed to investigate changes in left ven- tricular mass, QT dispersion, and high resolution signal av- eraged-ECG in hemodialysis patients after renal transplantation. PATIENTS AND METHODS Twenty-seven hemodialysis patients (18 male,9 female, mean age 308 years) and 24 healthy controls (14 male,10 female, mean age 336 years) were included in this study. No difference in age and sex distribution was found between hemodialysis patients and controls. Patients with amyloidosis, diabetes mellitus, congestive heart fail- ure, ischemic heart disease, bundle branch block, or atrial fibrillation in electrocardiogram, receiving any drug that may lengthen the QT interval were excluded. Hypertension was accepted as present if the patients have a sys- tolic pressure 140 mmHg or diastolic pressure 90 mmHg and/or was using antihypertensive medications including diuretics. The mean time on dialysis was 3321 months and all patients had been dialyzed for more than 6 months. Demographic features of the he- modialysis patients and controls were given in Table 1. All patients had been transplanted from living-related donor and allograft functioned immediately after transplantation. Two patients experienced acute rejection that responded to high dose steroid ther- apy. One patient died at the second month after transplantation due to noncardiac reason. All the patients have been treated with triple therapy including CycA (n:22) or FK506 (n:5), azathiopurine and prednisolone according to our transplantation protocol. Blood samples were drawn for measuring BUN, serum creatinine, electrolytes (including serum potassium, calcium, and magnesium) on the day of the measurement of QT intervals and the day after dialysis in hemodialysis period. Measurements of QT intervals, bio- chemical tests, and echocardiographic examinations were done be- fore and 1, 3, and 6 months after transplantation. Signal averaged- ECG parameters were measured at pretransplant period and 6 months after transplantation. Informed consent was taken from all patients. Echocardiographic examination was done with Hewlett-Packard So- nos 1000 echocardiographic system equipped with 2.5 and 3.5 MHz transducers. To get close to dry weight, echocardiographic parameters were taken the day after hemodialysis during the pretransplant period in all patients. The cardiac mass was calculated by the formula: left ventricle mass (g)=((LVID d +IVS d +LVPW d ) 3 -(LVID S ) 3 )13.6. The measurements of QT intervals. QT parameters were mea- sured from 12-lead ECG recorded the day after hemodialysis. Elec- trocardiograms were recorded by means of a 12-channel ECG re- corder (Hewlett-Packard M 1709-A, Hewlett-Packard, Andover, MA) at a paper speed of 50 mm/sec (gain 10 mm/mv). Before measurement of QT parameters, electrocardiograms were enlarged on the same photocopier by a factor of three. The QT interval was measured according to standard methods. Minimum of nine leads were studied in each patient. Minimum (QTmin), maximum (QTmax) duration of QT intervals, and their difference (QT dispersion; QTd) were mea- sured. Three recordings at third month and two recordings at sixth month were excluded from analysis due to technical problems. Each QT interval was corrected for patient heart rate according to Bazett’s formula: QTc=QT/(RR) All measures of QT intervals for each lead were blindly performed by one observer. Intraobserver variability for QT dispersion mea- surements was 12% (coefficient of variation). Signal average ECG measurement was performed on Marquette Centra electrocardo- graphic system. During hemodialysis period, recordings were taken 1 Supported by Turkish Kidney Foundation with grant 2000/19. 2 Department of Internal Medicine, Division of Nephrology. 3 Department of Cardiology. 4 Address correspondence to: Alaattin Yıldız, MD, I ˙ stanbul Tıp Faku ¨ ltesi, I ˙ c ¸, Hastalıkları ABD, Nefroloji BD 34390, Topkapı, I ˙ stan- bul, Turkey. 1523