Effect of hyperlipidemia on QT dispersion in patients without ischemic heart disease.

BACKGROUND

Lipoproteins are known to exert direct and indirect effects on cardiovascular function, but their effects on ventricular repolarization have not yet been clearly elucidated.

OBJECTIVES

To assess the effect of hyperlipidemia on the longest QT interval (QTmax) of the 12-lead surface electrocardiogram (ECG) and on QT dispersion (QTd) in type IIb hyperlipidemic patients without myocardial ischemia, and to compare these patients with healthy control subjects.

METHODS

Ninety-six hyperlipidemic patients (44 men and 52 women; mean age 53+/-13 years) and 101 healthy control subjects (43 men and 58 women; mean age 46+/-16 years) were examined. Total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol (LDL-C), triglyceride, apolipoprotein (apo) A1, apo B, lipoprotein(a), QTmax and QTd were measured. According to heart rate, corrected QTmax and corrected QTd were also determined.

RESULTS

A significant difference was observed between the two groups of subjects with respect to serum cholesterol, LDL-C, triglyceride, apo B, QTmax, corrected QTmax, QTd and corrected QTd. A positive significant correlation was found between cholesterol, triglyceride, LDL-C and all of the studied ECG parameters, between high density lipoprotein cholesterol and QTmax, apo B and QTd, and between body mass index and all of the studied ECG markers.

CONCLUSIONS

Hyperlipidemia may have a direct effect on the studied ECG markers.