Heart Rate Variability in Patients with Essential Hypertension

Background: Nonlinear measure of heart rate variability (HRV) is an emerging tool to detect changes in cardiac autonomic nerve function (CANF) in transfusion dependent thalassemic (TDT) patients. Slow breathing exercise (SBE) can significantly improve HRV in health and various diseases.
 Objective: To observe the effect of slow breathing exercise (SBE) on non linear measures of HRV in TDT patients.
 Methods: This prospective interventional study was done in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka in 2018 on 60 male TDT patients aged 15-30 years. Thirty patients received conventional treatment and 30 patients performed slow breathing exercise along with the conventional treatment for 3 months. Age and sex matched 30 healthy control were enrolled. All subjects were followed up at baseline and after 3 months. Non linear (Poincare) HRV parameters were recorded by Power Lab 8/35 AD Instrument, Australia. For statistical analysis paired sample ‘ t’ test and independent sample ‘t’ test were used.
 Result: SD1, SD2 and SD1/SD2 were found significantly lower in TDT patients compared to healthy control at baseline. After 3 months of slow breathing exercise, significant increment of these parameters occurred with trend of improvement in cardiac autonomic nerve function in this group of patients.
 Conclusion: Slow breathing exercise may improve cardiac autonomic nerve function and sympathovagal balance in transfusion dependent thalassemic patients.
 J Bangladesh Soc Physiol. 2019, June; 14(1): 26-32

1 Anu Muraja‐Murro, 1 Ari Pääkkönen, 2 Leena Jutila, 2 Reetta Kälviäinen, 3 Arto Immonen, 1 Sara Määttä, and 1 Esa Mervaala ( 1 Clinical Neurophysiology, Kuopio University Hospital, University of Kuopio, Kuopio, Finland ; 2 Neurology, Kuopio University Hospital, University of Kuopio, Kuopio, Finland ; and 3 Neurosurgery, Kuopio University Hospital, University of Kuopio, Kuopio, Finland ) Rationale: Mismatch‐negativity (MMN) is an auditory event‐related potential (ERP) produced by a deviant stimuli that occurs infrequenty among standard stimuli. MMN is thought to reflect the activation of an automatic change‐detector system that compares new auditory input with a short‐term memory trace generated by the previous auditory stimuli. MMN in human has been demonstrated from several cortical sites, but not to our knowledge from hippocampus or amygdala. This is surprising, given that these limbic structures are so essential for learning and memory functions. We could obtain MMN from these temporomesial structures using intracranial electrodes in adult patients undergoing presurgical evaluation for epilepsy surgery. Methods: 4 adults with intractable temporal lobe seizures (age 32–48 years) had each 2–4 stereotactically implanted 6‐contact depth‐electrodes at amygdalo‐hippocampal complex. The electrodes were implanted via lateral approach and their exact anatomical localizations were confirmed by MRI and CT in situ. After the post hoc anatomical localization of the depth‐electrodes, the presence of MMN could be studied from 6 hippocampi and 5 amygdalas (i.e., the electrode tips were exactly within amygdalo‐hippocampal complex). The most mesial depth‐electrode contacts were chosen for the MMN analysis with the MMN latency range of 120–250 ms, as well as with the P300 range of 250–500 ms. We analyzed possible statistically significant differences between the ERPs to deviant and standard tones. Results: A definite MMN within 120–250 ms latency range could be recorded from 4/6 hippocampi and 3/5 amygdalas. MMN was also detected within 250–500 ms latency range in 3/6 hippocampi and 2/5 amygdalas, respectively. In only one patient the hippocampal MMN resembled typical scalp‐recorded MMN. In all, the MMN decreased from the deepest contacts towards the cortex, suggesting a local maximum of MMN at the amygdalo‐hippocampal complex. Conclusions: Our data implicates that a local and early (120–500 ms post‐stimuli) automatic electrophysiological change‐detector system exists within the amygdalo‐hippocampal complex. This data is the first to demonstrate that also these temporomesial structures are activated and involved in mismatch detection, and is in line with recent sensory mismatch fMRI studies. Other sensory stimuli might also produce MMN in the same structures, possibly thus revealing a common function for hippocampus and amygdala in early sensory stimulus detection. 1 Tobias Loddenkemper, 2 Gabriel Moeddel, 1 Elia M. Pestana, 1 Deepak K. Lachhwani, 1 Ajay Gupta, 1 Prakash Kotagal, and 1 Elaine Wyllie ( 1 Department of Epilepsy and Sleep Disorder, The Cleveland Clinic Foundation, Cleveland, OH ; and 2 Department of Neurology, Universitaetsklinikum Muenster, Muenster, Westfalen, Germany ) Rationale: The intracarotid amobarbital test (IAT) is part of the presurgical workup of patients scheduled for epilepsy surgery to determine language and memory lateralization. Most information on results and complications are derived from adults. Little is known about children undergoing IAT. Difficulties arise from anxiety, need for barbiturate dosage adjustment, and impaired baseline memory in children with mental retardation [4]. The goal of this study was 1) to describe language lateralization in children with epilepsy and 2) to outline complications during IAT. Methods: 126 consecutive pediatric IAT performed at the Cleveland Clinic Foundation during a seven year period were reviewed. Results: 44 patients were age 5–12 years, 82 were age 13–18. 102 were right‐handed. Amobarbital (n = 96, average dose: 100 +‐ 25 mg) or Methohexital (n = 30, average dose 5 +‐ 1 mg) was injected into the left (n = 18), right (n = 13), or both (n = 95) ICA. Language was localized in 95 patients (75.4%): 75 [78.9%] were left, 6 [6.3%] were right, 14 [14.7%] bilateral language dominant. Neurological complications included prolonged lethargy impairing language and memory evaluation in 4 patients. Four children had a seizure after injection. Additionally, valid data could not be obtained due to fear or agitation in three children age 5–9 years. No lasting neurological deficits were seen. General complications included shortness of breath after contrast injection in one boy. One girl presented with fever of 38.5 C the night after the procedure complaining of groin pain. No other major complications were seen. Conclusions: This is one of the largest pediatric IAT series studied so far. The data on language lateralization agree with those previously reported [1, 2, 3]. The IAT in children is an invasive test with a potential for complications, as in adults, occuring in 10 out of 126 patients [7.9%]. Our series highlights the need for refinement and further development of novel methods to establish language lateralization in children during the evaluation for epilepsy surgery. REFERENCES 1. Loring D et al : . Neuropsychologia 28/8 ( 1990 ): 831 – 938 . 2. Mateer CA , Dodrill CB : . Hum Neurobiol 2 ( 1983 ): 135 – 142 3. Strauss E , Wada J : . Cortex 19 ( 1983 ): 165 – 177 ). 4. Szabo CA , Wyllie E : . Epilepsy Res 15 () ( 1993 ): 239 – 246 1 Eija Ronkainen, 1 Juha T. Korpelainen, 2 Heikki V. Huikuri, 1 Vilho V. Myllylä, and 1 Jouko I.T. Isojärvi ( 1 Department of Neurology, University of Oulu, Oulu, Finland ; and 2 Department of Internal Medicine, Division of Cardiology, University of Oulu, Oulu, Finland ) Rationale: To prospectively evaluate changes in interictal heart rate (HR) variability in patients with temporal lobe epilepsy (TLE) after 4 years follow‐up. Methods: A 24‐hour ECG recording was obtained at baseline and four years after first record

Background: Sedentary lifestyle is associated with low heart rate variability (HRV). Deep Relaxation Technique (DRT) increase HRV which reduces the risk of coronary heart diseases. Objectives: To assess HRV after practicing DRT to find out it’s effect on cardiac autonomic nerve function in sedentary subjects. Methods: This cross sectional study was carried out in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University between July 2012 and June 2013 on 30 apparently healthy sedentary females aged 25-35 years (study) who were practicing DRT with 3 months duration. For comparison, age and BMI matched 30 apparently healthy sedentary females who had no experience of relaxation technique (control) were also studied. Both groups were selected from the sedentary housewives by personal contact. The study subjects were the participants in a private yoga center in Dhaka. HRV was assessed by a Polygraph. Statistical analysis was done by Independent Sample ttest. Results: Resting mean heart rate (p<0.001) was significantly lower and mean R-R interval and SDNN (p<0.001), RMSSD (p<0.05) were significantly higher in the relaxation group than the control group. Conclusion: DRT improves cardiac autonomic nerve function with parasympathetic dominance in sedentary females. DOI: http://dx.doi.org/10.3329/jbsp.v8i2.18656Bangladesh Soc Physiol. 2013, December; 8(2): 65-69

Low heart rate variability in patients with clinical burnout

Objectives. Heart rate variability (HRV) and haemodynamic response to exercise (i.e. peak cardiac power output) are strong predictors of mortality in heart failure. The present study assessed the relationship between measures of HRV and peak cardiac power output. Design. In a prospective observational study of 33 patients (age 54 ± 16 years) with chronic heart failure with reduced left ventricular ejection fraction (29 ± 11%), measures of the HRV (i.e. R-R interval and standard deviation of normal R-R intervals, SDNN) were recorded in a supine position. All patients underwent maximal graded cardiopulmonary exercise testing with non-invasive (inert gas rebreathing) cardiac output assessment. Cardiac power output, expressed in watts, was calculated as the product of cardiac output and mean arterial blood pressure. Results. The mean RR and SDNN were 837 ± 166 and 96 ± 29 ms, peak exercise cardiac power output 2.28 ± 0.85 watts, cardiac output 10.34 ± 3.14 L/min, mean arterial blood pressure 98 ± 14 mmHg, stroke volume 91.43 ± 40.77 mL/beat, and oxygen consumption 19.0 ± 5.6 mL/kg/min. There was a significant but only moderate relationship between the RR interval and peak exercise cardiac power output (r = 0.43, p = .013), cardiac output (r = 0.35, p = .047), and mean arterial blood pressure (r = 0.45, p = .009). The SDNN correlated with peak cardiac power output (r = 0.42, p = .016), mean arterial blood arterial (r = 0.41, p = .019), and stroke volume (r = 0.35, p = .043). Conclusions. Moderate strength of the relationship between measures of HRV and cardiac response to exercise suggests that cardiac autonomic function is not good indicator of overall function and pumping capability of the heart in chronic heart failure.

Left atrial enlargement in mitral stenosis predisposes to atrial fibrillation (AF). Analysis of heart rate variability (HRV) prior to the onset of an arrhythmia may show alterations in autonomic balance that are known to predispose to the development of AF. The aim of this study was to determine whether HRV in patients with rheumatic mitral stenosis (MS) is abnormal in comparison to normal controls, and to find the relationship between left atrial size and HRV in patients with MS in sinus rhythm and in AF. A series of 24-hour ambulatory Holter electrocardiogram recordings were obtained for 10 consecutive, newly diagnosed untreated subjects with pure mitral stenosis in sinus rhythm, 10 with mitral stenosis complicated by atrial fibrillation and 10 age-matched normal controls. Digitized records were processed using time domain and power spectral analysis. In patients with mitral stenosis in sinus rhythm, we observed significant decrease of the standard deviation of the RR intervals (SDRR), as well as of the root mean square of successive RR interval differences (RMSSD) and Edinburgh index (sNN50), while in patients with AF, the RMSSD and sNN50 were much larger than those in normal. The areas under all spectral bands were markedly increased in patients with AF compared with normal. Furthermore, the high low frequency/high frequency (HLF/HF ratio) ratio was very small compared to normal. HRV measures were independent of atrial size in both groups. Decreased HRV in mitral stenosis patients with sinus rhythm suggests increased sympathetic activity in patients prone to atrial fibrillation, while marked increased of HRV in patients with AF may indicate that parasympathetic activity modulates the intrinsic behavior of the atrioventricular node during atrial fibrillation. The evaluation of HRV may be a useful tool for the identification of patients predisposed to AF.

ABSTRACTObjective: Cardiac autonomic neuropathy (CAN) is a severe and common, yet highly underdiagnosed, complication of Type 2 diabetes mellitus(T2DM). Subclinical CAN may have reduced heart rate variability (HRV) but normal Ewing battery test. This study was performed to evaluate theimportance of 5 minutes HRV for the detection of autonomic dysfunction in T2DM without (CAN-T2DM).Methods: This cross-sectional observational study was conducted at the Department of Physiology, Bangabandhu Sheikh Mujib Medical University(BSMMU) on 30 recently diagnosed T2DM (RT2DM) and 54 long-term CAN-male T2DM patients (LT2DM), aged 45-55 years, from the EndocrinologyOut Patient Department of BSMMU, Dhaka. 30 age and body mass index matched apparently healthy male subjects were control. Ewing battery testwas used to rule out CAN positive T2DM. HRV data were recorded by a polyrite-D and analyzed by software. HRV was assessed by time domainmethod. For statistical analysis, ANOVA and unpaired t-test were used.Results: Mean RR, standard deviation of NN intervals (SDNN) (p<0.05), and root mean square of the successive differences (RMSSD) were significantly(p<0.001) lower, and mean HR and SDNN/RMSSD were (p<0.001) significantly higher in LT2DM compared to RT2DM and control. In addition, SDNNwas also significantly (p<0.05) lower in RT2DM than that of control.Conclusions: Results conclude that autonomic dysfunction may occur in both LT2DM and RT2DM patients without neuropathy and 5 minutes HRVtest is an important tool for detecting subclinical CAN.Keywords: Type 2 diabetes mellitus, Cardiac autonomic neuropathy, Heart rate variability.

To assess heart-rate variability (HRV) measures of interictal electrocardiography (ECG) for drug-resistant epilepsy and to relate the findings to the outcome of vagus nerve stimulation (VNS) treatment. Time-domain, frequency-domain, and nonlinear analyses were used to analyze preoperative HRV measures in 32 patients with drug-resistant epilepsy who had received VNS implants at the same hospital and 32 healthy age- and sex-matched control subjects. HRV measurements based on ambulatory 24h ECG recordings were analyzed to identify seizure reduction 1year after VNS treatment. Responders were defined as having at least 50% seizure reduction 1year after treatment. Patients with drug-resistant epilepsy had significantly lower time domain (SDNN, RMSSD, pNN50), frequency domain (VLF, LF, HF, TP), and nonlinear (SD1, SD2) HRV measurements than matched healthy controls. None of the analyzed HRV measures of the responders differed significantly from their controls, whereas those of the nonresponders had significantly lower RMSSD, pNN50, HF, and SD1 than the responders. The preoperative HRV indices demonstrate that nonresponders have more pronounced impairment of their cardiac autonomic function than the responders. Presurgical HRV measurements representing parasympathetic cardiac control or vagal tone were significantly associated with the responsiveness to VNS. Thus the measurements show promise for predicting the reduction of seizure frequency after VNS treatment.

Background: Migraine is associated with autonomic nervous system dysfunction with reduced heart rate variability (HRV).Objective: To assess the cardiac autonomic function in migraine patients.Methods: This prospective study was carried out in the Department of Physiology, Bangabandhu Sheikh Mujib Medical University during 2013. Cardiac autonomic nerve function of 60 newly diagnosed untreated migraine patients aged 15-30 years, both male and female was assessed by analyzing time domain measures of HRV. Thirty age, sex, BMI matched healthy control were also assessed and compared. The diagnosed migraine patients were selected from the out patient department of Neurology, BSMMU, Dhaka. The HRV parameters were recorded by a 4 active channels, RMS polyrite-D. For statistical analysis, Independent Sample t-test was used.Results: Resting pulse rate, mean heart rate were found significantly higher and mean R-R interval, SDNN, RMSSD were significantly lower in all patients with migraine than those of healthy control.Conclusion: Autonomic dysfunction characterized by impaired cardiac vagal tone was associated with migraine.Bangladesh Soc Physiol. 2017, December; 12(2): 57-60

Measurement of heart rate variability can reveal autonomic nervous system function. Changes in heart rate variability can be associated with disease severity, risk of complications, and prognosis. We aimed to investigate the prognostic value of heart rate variability measurements in patients with moderate-to-severe traumatic brain injury after decompression surgery. We conducted a prospective study of 80 patients with traumatic brain injury after decompression surgery using a noninvasive electrocardiography device for data collection. Assessment of heart rate variability parameters included the time and frequency domains. The correlations between heart rate variability parameters and one-year mortality and functional outcomes were analyzed. Time domain measures of heart rate variability, using the standard deviation of the RR intervals and the square root of the mean squared differences of successive RR intervals, were statistically significantly lower in the group of patients with unfavorable outcomes and those that died. In frequency domain analysis, very low-frequency and total power were significantly higher in patients with favorable functional outcomes. High-frequency, low-frequency, and total power were statistically significantly higher in patients who survived for more than one year. Multivariate analysis using a model combining age and the Glasgow Coma Scale score with variables derived from heart rate variability substantially improved the prognostic value for predicting long-term outcome. These findings reinforced the concept that traumatic brain injury impacts the brain-heart axis and cardiac autonomic modulation even after decompression surgery, and variables derived from heart rate variability may be useful predictors of outcome.

Studies have assessed changesin autonomic variables in terms of heart rate variability (HRV) during meditation, but their results have been conflicting. Recently, Telles and colleagues’ excellent study 1 compared changes in HRV measures during the first four meditative states—cancalata (random thinking), ekagrata (nonmeditative focusing), dharana (meditative focusing), and dhyana (effortless meditation)— described in traditional yoga texts. Their results revealed that the discrepancy in changes in HRV measures might be due to the different stages. At the end of the Discussion section, the authors mention the ultimate state in yoga, samadhi, which manifests with breath suspension. They did not explore this advancedmeditativestateintheirstudy.Therefore,wewould like to share our results about changes in HRV measures during breath suspension. We collected and compared HRV measures in time and frequency domains, along with heart rate and blood pressure, during random thinking, breath meditation, and the advanced meditative stage with breath suspension in 10 meditative sessions conducted by an experienced meditator. The results (Table 1) show that none of HRV measures of time and frequency domains differed significantly during meditation. In contrast, heart rate and systolic blood pressure reliably decreased as meditation advanced. Because the meditation technique used in this study is close to meditative focusing, the results are concordant with the dharana state described in Telles and colleagues’ study. By using a device to monitor the chest circumstance of the meditator, the current study confirmed that the timing of breath suspension coincided with the subjective experience of breath suspension, complete quiescence, and absence of self-boundary. HRV measures, on the other hand, did not concord with the subjective experience of pure quiescence. Because other authors have argued that HRV is not an index of autonomic control of the circulation, 2 whether HRV can be an ideal index of sympathetic or parasympathetic activities remains questionable. According to the current results, the variations of HRV measures, manifested as the ratio of standard deviation to mean, are much greater than those of heart rate and blood pressure. This has also been shown in previous studies. 1,3,4 According to this view, HRV measures cannot be accurate indexes. The current results suggest that heart rate itself is a better HRV measure for meditation and agree with findings from Mukherjee et al. 5 These authors examined the sensitivity to mental effort and reliability of various HRV measures. Their

Effects of digoxin on time domain measures of heart rate variability in patients with stable chronic cardiac failure: withdrawal and comparison group studies

Background: The dysfunction of the autonomic nervous system is a major pathophysiologic agent in essential hypertension and potentially a factor in insufficient blood pressure management despite pharmacological therapy. Non-invasive indicators of autonomic cardiovascular regulation include heart rate variability (HRV) and baroreflex sensitivity (BRS); nevertheless, their role in blood pressure management in non-acute clinical life has not been studied well enough. Objectives: To determine the relationship between heart rate variability and baroreflex sensitivity with blood pressure regulation in essential hypertension patients. Methods: This was a cross-sectional study that took place between May 2024 and May 2025 and involved 100 adults with essential hypertension. Standardized procedures were employed in measuring blood pressure, and the respondents were divided into two groups, namely controlled and uncontrolled hypertension. HRV measurements were made in both time and frequency domains through short-term electrocardiograph recordings, whereas baroreflex sensitivity was measured under a non-invasive spontaneous sequence approach. These were done by using comparative and correlation analyses in order to explore the relationship between the autonomic parameters and blood pressure levels. Results: Of the 100 participants, 46% had controlled hypertension and 54% had uncontrolled hypertension. Uncontrolled hypertension patients recorded much lower HRV indices, such as SDNN and RMSSD, as well as high-frequency power, and a much higher LF/HF ratio (p < 0.001). In the state of uncontrolled, baroreflex sensitivity was significantly lower (p < 0.001). There were strong negative relationships between systolic and diastolic blood pressure variables and HRV parameters and baroreflex sensitivity. Multivariate regression analysis has revealed that reduced baroreflex sensitivity and lower SDNN are the independent predictors of poor blood pressure control. Conclusion: Impaired autonomic regulation, reflected by reduced heart rate variability and baroreflex sensitivity, is strongly associated with uncontrolled essential hypertension. Assessment of autonomic function may enhance risk stratification and support more individualized management of hypertensive patients.

Monitoring collegiate soccer players during a congested match schedule: Heart rate variability versus subjective wellness measures.

Patients with anorexia nervosa or bulimia nervosa often have signs of autonomic dysfunction potentially deleterious to the heart. The aim of this study was to ascertain the nonlinear properties of heart rate variability in patients with eating disorders. A group of 33 women with eating disorders (14 anorexia, 19 bulimia) and 19 healthy controls were included in the study. Conventional time- and frequency-domain heart rate variability measurements, along with nonlinear heart rate variability measurements including the short-term fractal scaling exponent α and approximate entropy (ApEn) were calculated. Anorexia nervosa patients exhibited decreased values of α, while bulimia nervosa patients had decreased values of ApEn. Low-frequency heart rate variability was decreased in patients with anorexia. In conclusion, these results are compatible with the view that a more severe alteration of cardiac autonomic function is present in anorexia than in bulimia.