Abstract Body (Do not enter title and authors here): Background: In patients with type 2 diabetes (T2D), hyperglycemia and glycemic variability lead to prolongation and greater heterogeneity of ventricular repolarization, manifested on the electrocardiogram through an increase in QT, QTc, TpeakTend (TpTe) intervals and the TpTe/QT ratio, increasing the risk of potentially malignant arrhythmias. Dapagliflozin has demonstrated efficacy in reducing cardiovascular events in T2D patients and in the risk of serious ventricular arrhythmias and sudden cardiac death. However, the exact mechanisms by which dapagliflozin confers this protection have not yet been fully elucidated.
Goals/Aims: The main objective of the study was to evaluate the impact of dapagliflozin on the TpTe interval of patients with T2D, and secondarily, it examined its impact on various electrocardiographic parameters such as the QT and QTc intervals, the TpTf/QT ratio, QT dispersion, J-T peak interval, QRS-T angle and heart rate.
Methods: This randomized, prospective, multicenter and open-label study involved 174 patients with T2D, divided into two groups: one treated with dapagliflozin and the other with optimized medical therapy without iSGLT2. Clinical, electrocardiographic, laboratory and echocardiographic evaluations were carried out at the beginning and after three months. The statistical analysis included means, standard deviations, quartiles, and frequencies, with 95% confidence intervals, using Chi-square (or Fisher) and t-test (or Mann-Whitney) for initial differences, and a linear mixed-effects model to evaluate the results, adopting a significance level of 0.05.
Results: The TpTe interval was significantly reduced in the dapagliflozin group from 76.87 ± 12.47 to 67.80 ± 10.34 (p<0.001), and the QTc interval reduced from 424.07 ± 30.76 to 411.26 ± 25.31 (p=0.022). The TpTe/QT ratio in the dapagliflozin group was shortened from 0.20 ± 0.03 to 0.18 ± 0.02 (p<0.001). Both groups showed reductions in mean blood glucose and HbA1c, with a greater decrease observed in the control group. No significant changes were recorded in other variables analyzed.
Conclusion: In patients with T2D, dapagliflozin significantly reduced the duration of the TpTe and QTc intervals, in addition to the TpTe/QT ratio. These findings indicate a decrease in ventricular electrical remodeling with a potential cardioprotective effect of dapagliflozin, which would partly explain its benefits in reducing potentially malignant ventricular arrhythmias and sudden cardiac death.