Early identification of cardiac autonomic neuropathy using complexity analysis in children with type 1 diabetes.

AIM: In children and adolescents, there are significant limitations to detecting cardiac autonomic neuropathy (CAN), an important contributor to morbidity and mortality in adults with type 1 diabetes (T1D). The analysis of heart rate variability (HRV) is one method available to detect CAN. Some evidence shows traditional linear HRV measures detect abnormalities in youth with T1D. In this study, we aimed to assess whether non-linear complexity analysis of HRV would assist identification of CAN in youth with T1D and to assess contributory factors. METHODS: We studied 19 youth with T1D and 17 healthy controls. Each had an electrocardiogram recorded continuously for 10 min, at a sampling frequency of 1000 Hz. Using Labview software and an algorithm for complexity analysis, along with standard time-domain and spectral analysis, recordings of the electrocardiogram were analysed to detect differences in HRV between groups. RESULTS: Youth with T1D had significantly higher sample entropy than controls (P = 0.015) suggesting increased complexity in HRV, but similar detrended fluctuation analysis (P = 0.68). Youth with T1D also had increased % high frequency power (P = 0.017) and reduced mid-frequency power (P = 0.019) on spectral analysis. There were no differences in heart rate or blood pressure responses to standing, or time-domain analysis of HRV. Within the T1D group, sample entropy correlated strongly with triglycerides (r = 0.76, P = 0.001) and detrended fluctuation analysis correlated strongly with serum potassium (r = -0.86, P < 0.001). CONCLUSIONS: Complexity analysis of HRV, particularly using sample entropy, may aid detection of CAN in youth with T1D.

Why New Zealand must rapidly halve its greenhouse gas emissions.

New Zealand must commit to substantial decreases in its greenhouse gas emissions, to avoid the worst impacts of climate change on human health, both here and internationally. We have the fourth highest per capita greenhouse gas emissions in the developed world. Based on the need to limit warming to 2 degrees C by 2100, our cumulative emissions, and our capability to mitigate, New Zealand should at least halve its greenhouse gas emissions by 2020 (i.e. a target of at least 40% less than 1990 levels). This target has a strong scientific basis, and if anything may be too lenient; reducing the risk of catastrophic climate change may require deeper cuts. Short-term economic costs of mitigation have been widely overstated in public debate. They must also be balanced by the far greater costs caused by inertia and the substantial health and social benefits that can be achieved by a low emissions society. Large emissions reductions are achievable if we mobilise New Zealand society and let technology follow the signal of a responsible target.