Effects of Pioglitazone on the Electrocardiogram in the Goto-Kakizaki Type 2 Diabetic Rat Heart

Cardiovascular complications are the major cause of morbidity and mortality in diabetic patients. Pioglitazone (PIO) is used for the treatment of type 2 diabetes mellitus and there is some evidence that it may improve ventricular function in diabetic patients. The effects of PIO on electrical conduction in the Goto-Kakizaki (GK) type 2 diabetic rat heart have been investigated. Transmitter devices were surgically implanted in GK and control rats aged 7 months. PIO at concentrations (2.5 to 20 mg/kg) was added to the drinking water. Animals received each concentration of PIO for 2 weeks. Bodyweight and blood glucose were measured periodically. The electrocardiogram was recorded throughout the study. Blood glucose was higher in GK rats compared to controls and was progressively reduced in GK rats treated with increasing concentrations of PIO. A modest reduction in heart rate was associated with a significant increase in PQ interval in GK rats compared to controls. Heart rate and PQ interval were not additionally altered by PIO. QRS complex and QT interval were not altered in GK compared to control or by PIO. In conclusion daily oral doses of PIO in the range 2.5 to 20 mg/ kg during a period of 14 weeks appeared to have little effect on electrical conduction in GK and control rat heart.