Electrophysiological Assessment of Cardiac Complications in Chronic Diabetic Minipigs
Stricker-Krongrad, A., Jones, M.R., Liu, J., Bouchard, G.F.,
Abundant evidence shows that patients with type 1 diabetes are at high risk for several cardiovascular disorders. Our objective was to assess potential cardiac electro-pathophysiology changes linked to chronic insulin-dependent diabetes in the Yucatan miniature swine. Diabetic animals were divided into different groups based on duration of diabetes. Routine measurements of electrocardiograms, including HR, RR, PR, QRS, QT and QTc, were done. A heart rate correction for the QT interval (QTc) was calculated using the Fridericia method [QTc=QT/(cubed root of RR)]. Mean heart rate was decreased for the diabetic Groups compared to the mean heart rate for normal animals. The mean PR interval was increased in all diabetic animals compared to normal animals and the effect increase with the duration of diabetes. The mean QRS interval was increased for all of the diabetic animals compared to normal animals. There were no pronounced QTc abnormalities in this study when comparing diabetic to the normal animals although one animal did have a QTc prolongation of 43 msec. In addition, one animal had a prolonged PR segment (224 msec) associated with frequent ventricular escape complexes. This abnormality in rhythm would possibly go along with the duration and severity of the diabetes. In conclusion, chronic diabetes in Yucatan miniature swine manifests with progressive effects on heart rate, PR interval, and QRS duration. This indicates that the diabetic minipig could provide a good model to test preventative approaches for progressive cardiac therapies in diabetes, using electrocardiography segments as markers of early heart damage.