Cardiac aging, including cardiometabolic disturbances, is defined as a progressive and intrinsic decline in heart function, which is also a combination of metabolic dysfunctions mainly characterized by insulin resistance and long-QT, via prolonged late-phase repolarizations of ventricular action potentials (APs). So, we hypothesized a contribution of dysfunctional KCNQ1/KCNE1-channels to these abnormal electrical activities in elderly mammal hearts and positive responses to insulin application. Furthermore, taken into consideration β3-AR activation role in insulin-resistant hearts, we aimed to investigate the possible correlations between dysfunctional KCNQ1/KCNE1-channels, β3-AR activation, and the effect of insulin application on these correlations in insulin-resistant aged rat (24-month-old) ventricular cardiomyocytes.