Heart Rate Variability and Diastolic Dysfunction in Children with Type 1 Diabetes: A Cross-Sectional Study

Reduced heart rate variability (HRV) is an indicator of subclinical cardiac autonomic dysfunction. This study aimed to evaluate the relationship between HRV and diastolic dysfunction in children with type 1 diabetes mellitus (T1DM), and to examine the impact of glycemic control and diabetes duration on subclinical cardiovascular changes. This cross-sectional study included 57 children with T1DM and 40 age and sex matched healthy controls. HRV was assessed using 24-hour Holter monitoring, and diastolic function was evaluated with Doppler echocardiography. Children with type 1 diabetes had lower heart rate variability indices compared to controls, particularly in those with poor glycemic control. Early diastolic dysfunction was observed in the diabetic group, indicated by higher A-wave velocities (67.0 ± 5.9 cm/s vs. 62.5 ± 7.4 cm/s, p=0.004), prolonged deceleration time (181.3 ± 42.5 ms vs. 143.3 ± 25.1 ms, p<0.001), and increased isovolumic relaxation time (52.6 ± 9.8 ms vs. 44.4 ± 10.2 ms, p<0.001). Chronic high blood glucose levels and longer diabetes duration were strongly associated with both reduced heart rate variability and diastolic abnormalities. In conclusion, this study highlights the potential of heart rate variability parameters as early markers of subclinical myocardial changes in children with type 1 diabetes. Early detection and targeted interventions based on these parameters may may contribute to reducing long-term cardiovascular risks in this population.