Heart Rate Variability Analysis Parameters Research Articles

Heart rate variability in the course of chemotherapy and haematopoietic stem cell transplantation for peadiatric patients with haematological malignancies.

High-dose chemotherapy and haematopoietic stem cell transplantation are essential for patients with paediatric haematologic diseases, although cardiotoxicity remains a concern. Heart rate variability analysis can evaluate autonomic nervous function interactions with cardiac function. This study aimed to characterise heart rate variability differences between patients undergoing chemotherapy and controls, and the effects of haematopoietic stem cell transplantation on the autonomic nervous system in patients with haematological malignancies. Nineteen patients (11 male, median age: 11.6 years) who received conventional chemotherapy followed by transplantation and 19 non-transplant patients (10 male, median age: 11.5 years) receiving chemotherapy only between 2006 and 2018 for haematological malignancies were retrospectively enrolled. Data from 24-hour Holter monitoring were recorded after chemotherapy and before and after transplantation. Heart rate variability was analysed in patients and 32 matched normal controls. There were significant differences between patients and normal controls in all heart rate variability analysis parameters apart from coefficient of variation of RR interval and standard deviation of the average normal RR interval for all 5-minute segments during sleeping. There was a significant difference in the cumulative anthracycline dose and heart rate variability during sleep between the non-transplant and pre-transplant groups. We observed no remarkable differences in time-domain analysis parameters between before and after transplantation, although the low-frequency component of power-spectrum analysis during awake hours was significantly decreased after transplantation. Conventional chemotherapy for paediatric haematologic diseases may be a risk factor for autonomic dysfunction. Further declines in heart rate variability after transplantation appear minor.

Heart rate variability may be more useful than pulse transit time for confirming successful caudal block under general anesthesia in children

Background: Confirming a successful caudal block is challenging in the pediatric population. Pulse transit time (PTT) may reflect the decrease in arterial resistance and may act as a potential indicator for confirming successful peripheral nerve or axial block. Heart rate variability (HRV) is also a possible candidate because it may be influenced by variation in sympathetic tone. We expected an increasing PTT pattern and change in HRV parameters after caudal block. Methods: We enrolled 27 male patients (range, 1-4 years old) who were scheduled for urological surgeries. Caudal block was performed with 1 ml/kg of 0.25% ropivacaine and 1 : 200,000 epinephrine under sevoflurane anesthesia after the surgery. Successful block was confirmed by auscultation and ultrasonography. PTT and HRV parameters, such as standard deviation of normal-to-normal intervals, root mean square of successive differences, very low-frequency power, low-frequency power (LF), high-frequency power (HF), LF/HF ratio, approximate entropy (ApEn) were calculated based on electrocardiography from 1 min before to 5 min after the block. Those variables were analyzed by repeated measures analysis of variance. Results: No significant change was found in PTT with time interval after caudal block. Heart rate and ApEn of the R-R interval decreased with time interval (P = 0.001, 0.033, respectively). Some HRV parameters showed notable changes, although statistically insignificant. Conclusions: The PTT pattern may not be an indicator for successful caudal block. However, heart rate with parameters of HRV analysis may be alternatives. Keywords: Caudal anesthesia; Heart rate

Improving Heart Rate Variability in Sleep Apnea Patients: Differences in Treatment with Auto-titrating Positive Airway Pressure (APAP) Versus Conventional CPAP

The effect of positive airway pressure treatments in different modalities on the cardiovascular consequences of the disease in sleep apnea patients is still unclear. We aimed to compare auto-titrating positive airway pressure (APAP) and conventional continuous positive airway pressure (CPAP) in terms of improving heart rate variability (HRV) in obstructive sleep apnea patients. This was a prospective study done in a tertiary research hospital. All patients underwent a manual CPAP titration procedure to determine the optimal pressure that abolishes abnormal respiratory events. Then patients underwent two treatment nights, one under APAP mode and one under conventional CPAP mode with a 1-week interval. Forty newly diagnosed obstructive sleep apnea patients were enrolled in the study. We compared heart rate variability analysis parameters between the APAP night and the CPAP night. This final analysis included the data of 28 patients (M/F: 22/6; mean age = 46 +/- 10 years). Sleep characteristics were comparable between the two treatment nights, whereas all-night time domains of HRV analysis such as HF, nuLF, and LF/HF were different between APAP and CPAP nights (2.93 +/- 0.31 vs. 3.01 +/- 0.31; P = 0.041; 0.75 +/- 0.13 vs. 0.71 +/- 0.14; P = 0.027; and 4.37 +/- 3.24 vs. 3.56 +/- 2.07; P = 0.023, respectively). HRV analysis for individual sleep stages showed that Stage 2 LF, nuLF, nuHF, LF/HF parameters entirely improved under CPAP treatment whereas APAP treatment resulted in nonsignificant changes. These results suggest that despite comparable improvement in abnormal respiratory events with APAP or CPAP treatments, CPAP may be superior to APAP in terms of correcting cardiovascular alterations in sleep apnea patients.

Analysis of Heart Rate Variability does not Identify the Patients at Risk of Atrial Fibrillation after Coronary Artery Bypass Grafting

Objective : Analysis of heart rate variability (HRV) is a non-invasive method for assessing cardiac autonomic regulation. This study was designed to investigate whether preoperative short-term HRV analysis could identify the patients at high risk of atrial fibrillation (AF) after coronary artery bypass grafting (CABG). Design : HRV measurement was performed preoperatively for 92 elective CABG patients. Results : Thirty patients had AF postoperatively while 62 remained in sinus rhythm (SR). Logistic regression analysis identified two independent predictors for AF after CABG: increased age with an odds ratio (OR) 1.06 per year and higher body mass index (BMI) with an OR 1.18 per unit. However, no measured parameters of HRV analysis differed significantly between AF and SR groups. Conclusion : The patients at high risk of AF after CABG cannot be identified by preoperative short-term HRV analysis performed during standardized physiological conditions. Advanced age and higher BMI were independent risk factors of AF after CABG in this study.