Autonomic neuropathy and QT interval in hemodialysed patients.
BACKGROUND
QT interval prolongation increases the risk of ventricular arrhythmias and sudden death in diabetic autonomic neuropathy and ischemic heart disease. In end-stage renal disease (ESRD), the effects of hemodialysis on QT interval are diverse and the influence of autonomic neuropathy has yet to be clearly defined.


METHODS
Sixty-nine ERSD patients (age 64 +/- 14) were studied. Prior to the dialysis session, patients underwent four standard autonomic cardiovascular tests; before and after the dialysis session, a 12-lead ECG was recorded. Corrected QT intervals (QTc) were measured and QT dispersion (QTd) was calculated. Twelve subjects (age 59 +/- 6) with normal renal function served as control group.


RESULTS
Compared to controls, ESRD patients showed a longer QTc (434 +/- 26 vs 414 +/- 28 ms; p = 0.016) and a similar QTd (35 +/- 13 vs 37 +/- 14 ms; p = 0.54).QTc was > 440 ms in 33.3% of the patients. No difference in the prevalence or score of autonomic neuropathy was observed between the subgroups with and without a prolonged QTc. After the hemodialysis session, QTc increased in 56% and decreased in 43% of the patients, and QTd increased in 45 % and decreased in 55% of the patients. QTc and QTd changes were not related to the presence of autonomic neuropathy.


CONCLUSIONS
A large variability in QTc and QTd response was observed after hemodialysis. Autonomic neuropathy did not contribute to QTc and QTd length, nor to QTc and QTd change after dialysis.
Dept. of Internal Medicine, University of Turin, Turin, Italy. simmaule@tin.it
Simona
S
Maule
Massimo
M
Veglio
Fabio
F
Mecca
Chiara
C
Calvo
Guido
G
Martina
Martino
M
Marangella
Roberto
R
Quadri
Paolo
P
Cavallo Perin
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001342:Autonomic Nervous System Diseases / Q000209:etiology* / Q000503:physiopathology; D001794:Blood Pressure / Q000502:physiology; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000000981:diagnostic imaging; D007676:Kidney Failure, Chronic / Q000150:complications* / Q000503:physiopathology / Q000628:therapy; D008133:Long QT Syndrome / Q000209:etiology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis; D014463:Ultrasonography