QT dispersion before and after hemodialysis

Sudden cardiac death is common in patients on hemodialysis, and may occur i n the immediate postdialysis period, when ventricular premature complexes a re common. Elevated QT dispersion (Maximum - Minimum QT interval on standar d 12-lead electrocardiogram) is associated with increased risk of ventricul ar arrhythmias following myocardial infarction, but has not previously been assessed in patients with chronic renal failure. We studied electrocardiog rams recorded in 50 patients before and after a single hemodialysis session , and in 20 control subjects. QT dispersion was significantly higher in pat ients (63.1 +/- 20.6 ms) compared with control subjects (36.0 +/- 13.7 ms; P < 0.001) and rose significantly after hemodialysis to levels comparable t o those seen following myocardial infarction (76.6 +/- 27.0 ms; P < 0.01). Because QT dispersion reflects nonhomogeneous recovery of ventricular excit ability, hemodialysis patients may be at significantly greater risk of reen trant arrhythmias and sudden death in the postdialysis period.