The relationship between iron stores and corrected QT dispersion in patients undergoing hemodialysis.

OBJECTIVE: Cardiac arrhythmias commonly occur in hemodialysis patients. QT dispersion (QTd=QTmax-QTmin) reflects heterogeneity of cardiac repolarization, and increased QTd is known to predispose the heart to ventricular arrhythmias and sudden cardiac death. The aim of our study was to assess the association of iron stores, reflected by transferrin saturation (TSAT) and ferritin, with the dispersion of corrected QT intervals (QTc) in patients undergoing hemodialysis.

METHODS: This cross-sectional, case-controlled study included 40 patients (23 men and 17 women) with renal failure undergoing hemodialysis (Patient group) and 27 subjects (10 men and 17 women) with normal renal function (Control group). In all patients and control subjects, QT intervals were measured on electrocardiogram, and QTc intervals and QTc dispersion were calculated. Electrolyte, hemoglobin and serum TSAT and ferritin levels were also determined.

RESULTS: Hemodialysis patients had significantly greater QTc dispersion compared to that of control subjects (61.7+/-23.0 msec vs. 46.0+/-15.7 msec; p=0.001). Though serum iron levels were significantly associated with greater QTc dispersion (r=0.324, p=0.042), other electrolyte levels, duration of dialysis, TSAT and serum ferritin levels were not.

CONCLUSION: Although hemodialysis patients have greater QTc dispersion than control subjects, their levels of iron stores as reflected by TSAT and ferritin levels, does not correlate with the degree of QT dispersion.