Differential Analysis of Heart Rate Variability in School Going Adolescents: Comparing Healthy Individuals with Those Experiencing Depression and Anxiety.

Background Adolescents often struggle with depression and anxiety, which can greatly affect their well-being and functioning. Early detection is crucial for timely intervention and long-term health. Objective The objective of this study is to compare heart rate variability between depressed and anxious adolescents and their healthy peers. Method In this cross-sectional study, adolescents aged between 13-18 years were randomly selected from various schools. Participants were assessed for depression and anxiety using the Revised Child Anxiety and Depression Scale-25 (RCADS-25). Heart Rate Variability was measured using Power lab, with recorded variables including Median normal to normal interval (NN), Standard deviation of the normal-to-normal interval (SDNN), Root Mean Square of the Successive Differences (RMSSD), Percentage of successive normal to normal interval differing by more than 50 milliseconds (pNN50), Low frequency power % (LF), High frequency power % (HF), and the LF:HF ratio. Result Reduction in certain time domain HRV parameters was observed among the subset of depressed students in Classes XI and XII, such as NN interval (p=0.019), SDNN (p=0.024), and RMSSD (p=0.034). Anxious adolescents showed a significant reduction in HRV compared to their healthy counterparts [(NN, p<.001), (SDNN, p=0.011), (RMSSD, p=0.017), (pNN50, p=0.016). Students with symptoms of both depression and anxiety demonstrated significantly reduced HRV parameters compared to the healthy group, affecting NN, (p<.001), SDNN, (p=0.003), RMSSD, ( p<.001), pNN50, (p< .001), HFP %, (p< .001) and LF: HF (p=.005). This association was observed in both males and females. Conclusion Adolescents with depression and anxiety have lower HRV than their healthy peers. Monitoring HRV may help to objectively detect these conditions.

Plasma C-terminal proEndothelin-1 (CTproET-1) is affected by age, renal function, left atrial size and diastolic blood pressure in healthy subjects.

Endothelin-1 (ET-1) is a short chained peptide primarily of endothelial origin. Concentrations of this peptide are increased in subjects with hypertension, primary pulmonary hypertension and myocardial infarction, however its short half-life makes quantification difficult. The C-terminal of proET-1 (CTproET-1) is stoichiometrically secreted with its bioactive peptide and would be a valid method of measuring the active peptide as it has a stable half-life and is less resistant to proteolytic cleavage. The objective of this study was to understand the factors (clinical, echocardiographic and biochemical) that specifically influence plasma CTproET-1 in healthy subjects. 518 healthy volunteers were recruited from a screening study. Plasma CTproET-1 concentrations were quantified using a novel immunoluminometric sandwich assay. In multivariate analyses, age (P<0.001), diastolic BP (P=0.007), LA size (P=0.001) and eGFR (P<0.001) were independently predictive of plasma CTproET-1 levels in the healthy subjects. Therefore the interpretation of plasma CTproET-1 levels in such individuals should take into account these variables to avoid potential confounding.

The diagnostic performance of mid-regional portion of pro-atrial natriuretic peptide for the detection of left ventricular hypertrophy in Caucasian hypertensive patients.

Left ventricular hypertrophy (LVH) is predictive of cardiovascular disease. The vasodilator, natriuretic and diuretic actions of atrial natriuretic peptide (ANP) support a role in the pathophysiology of hypertension. Measuring the redundant precursor fragment mid-regional portion of pro-atrial natriuretic peptide (MRproANP) overcomes the technical difficulties of quantifying the bioactive ANP. This study sought to investigate the diagnostic and prognostic utility of MRproANP in a hypertensive Caucasian patient population. A total of 194 hypertensive patients (39 patients with LVH, 69±7.82 years of age, 74% female vs 155 patients without LVH, 68±6.51 years of age, 71% female) were derived from a screening study. Plasma MRproANP concentrations were quantified using immunoluminometric assays. Hypertensive patients with LVH had higher MRproANP concentrations than those without LVH (103.04 (50.58) vs 84.11 pmol l(-1) (44.82); P=0.014). Independent predictors of left ventricular mass index were LogMRproANP (P=0.022), male gender (P<0.001), body mass index (P=0.001) and history of angina or myocardial infarction (P=0.009). The receiver operating curve for MRproANP for the detection of LVH was limited, yielding an area under the curve of only 0.628 (confidence interval 0.523-0.733; P=0.014). Therefore, the role of MRproANP may not lie in the diagnosis of LVH but in monitoring the response to therapy. A nonsignificant trend towards greater mortality in patients with above-median MRproANP levels compared with below-median levels (P=0.167) was observed. Larger studies are required to assess its prognostic utility further.