Complex influence of endocrine and neuro-vegetative disorders on ventricular repolarization in diabetic patients

Background Diabetic patients have an increased QT interval duration corrected for heart rate (QTcF) and an increased risk of sudden death, as compared to healthy subjects. Diabetics are characterized by increased insulin resistance and are frequently affected by autonomic neuropathy and other hormonal disorders, such as hypogonadism and decreased IGF1 levels. Data regarding influence of these latter conditions on QT interval duration in diabetics are scarce. Methods A cohort of 195 type II diabetic patients at high cardiovascular risk were prospectively included. Circulating concentrations of FSH, testosterone, insulin, glycaemia, kalemia, HbA1c were measured concomitantly to the recording of a digitized electrocardiogram. Orthostatic hypotension was evaluated at the same time, as a surrogate of autonomic neuropathy. Treatments influencing QTc were recorded and classified according to Crediblemeds ® . Results The cohort consisted of 154 men (79%) aged 64.8 ± 8.6 years with a mean QTcF of 418 ± 25 msec. Eleven patients (5.6%) were taking a medication belonging to Crediblemeds’ known Torsade de Pointe risk category. Twenty-six patients (13.3%) had an orthostatic hypotension. According to multivariable analysis, age (β = 0.14, P  = 0.04), presence of orthostatic hypotension (β = 0.14, P  = 0.02), intake of medication at known risk of Torsade de Pointe (β = 0.22, P  = 0.001), HbA1c, kalemia and FSH levels (β = 0.232, P P  = 0.005; β=0.14, P  = 0.04; respectively) were related to QTcF ( r 2  = 0.22, P Conclusion In diabetic patients, cardiac repolarization is influenced by complex interactions between presence of autonomic neuropathy, gonadotropins, poor glycemic control and ionic disturbances.