• Journal of Biomedical Engineering Research
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• v.28 no.4
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• pp.441-448
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• 2007

Heart rate variability (HRV) in electrocardiogram (ECG) is an important index for understanding the health status of heart and the autonomic nervous system. Most HRV analysis approaches are based on the proper heart rate (HR) data. Estimation of heart rate is thus a key process in the HRV study. In this paper, we report an innovative method to estimate the heart rate. This method is mainly based on the concept of periodicity transform (PT) and instantaneous period (IP) estimate. The method presented is accordingly called the "PT-IP method." It does not require ECG R-wave detection and thus possesses robust noise-immune capability. While the noise contamination, ECG time-varying morphology, and subjects' physiological variations make the R-wave detection a difficult task, this method can help us effectively estimate HR for medical research and clinical diagnosis. The results of estimating HR from empirical ECG data verify the efficacy and reliability of the proposed method.

• Journal of the Korean Society of Radiology
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• v.17 no.1
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• pp.53-62
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• 2023

The purpose of this study is to find an optimized imaging technique and evaluate its usefulness by comparing and analyzing the difference in contrast enhancement of lower extremity artery according to the patient's heart rate during lower extremity Computed Tomography Angiography examination. From January 2022 to August 22nd, 139 outpatients who visited Ajou University Hospital and underwent lower extremity angio CT examination were targeted. According to the heart rate, the groups were divided into four groups: A(HR ≤65), B(65 < HR < 80), C(80≤ HR). In addition, among patients with a heart rate of 65 or less, the heart rate was considered, and the scan was divided into D, E, F group with a delay time. The time of arrival of contrast medium and the average value of contrast enhancement were compared and analyzed. As a result of quantitative evaluation, B and C groups with a heart rate of more than 65 times had better HU values in the popliteal artery than A group (HR ≤ 65), and D group showed better HU improvement effects compared to A group (p<0.001). The comparative analysis with other groups was insignificant. The difference in heart rate affected the angiographic intensity of the lower extremities artery. Therefore, it is effective to apply the appropriate test timing for each patient by using the heart rate during the lower extremity angio CT Scan.

• International Journal of Heart Failure
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• v.6 no.3
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• pp.119-126
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• 2024

Background and Objectives: Beta-blockers (BBs) improve prognosis in heart failure (HF), which is mediated by lowering heart rate (HR). However, HR has no prognostic implication in atrial fibrillation (AF) and also BBs have not been shown to improve prognosis in heart failure with preserved ejection fraction (HFpEF) with AF. This study assessed the prognostic implication of BB in HFpEF with AF according to discharge HR. Methods: From the Korean Acute Heart Failure Registry, 687 patients with HFpEF and AF were selected. Study subjects were divided into 4 groups based on 75 beats per minute (bpm) of HR at discharge and whether or not they were treated with BB at discharge. Results: Of the 687 patients with HFpEF and AF, 128 (36.1%) were in low HR group and 121 (36.4%) were in high HR group among those treated with BB at discharge. In high HR group, HR at discharge was significantly faster in BB non-users (85.5±9.1 bpm vs. 89.2±12.5 bpm, p=0.005). In the Cox model, BB did not improve 60-day rehospitalization (hazard ratio, 0.93;95% confidence interval [95% CI], 0.35-2.47) or mortality (hazard ratio, 0.77; 95% CI, 0.22-2.74) in low HR group. However, in high HR group, BB treatment at discharge was associated with 82% reduced 60-day HF rehospitalization (hazard ratio, 0.18; 95% CI, 0.04-0.81), but not with mortality (hazard ratio, 0.77; 95% CI, 0.20-2.98). Conclusions: In HFpEF with AF, in patients with HR over 75 bpm at discharge, BB treatment at discharge was associated with a reduced 60-day rehospitalization rate.

• Journal of Veterinary Clinics
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• v.40 no.6
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• pp.464-467
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• 2023

The autonomic regulation of heart rate (HR) is an indicator of the body's ability to adapt to an exercise stimulus. However, there are no reports on this topic in relation to Jeju horses used for racing. The aim of this study was to analyze the HR responses of Jeju horses during race trials and to investigate the correlation between HR and performance in these horses. HR data were collected from 17 healthy 2- to 7-year-old Jeju horses wearing HR monitors during race trials. Pearson correlation coefficients was used to determine the significance of the association between the race trial time and HR. A significant inverse correlation was observed between the race trial time (performance) and both the maximal HR (HRmax, r = -0.69, p < 0.01) and HR reserve (HRR) (HRmax - average HR during the warm-up period, r = -0.63, p < 0.01) and between the HRR and HRmax (r = 0.73, p < 0.01). Horses with a lower average HR during the warm-up period and higher heart rates during the trial achieved faster race trial times. This study reports the first HR measurements in Jeju horses during race trials, providing new insights into the HR response of this breed to exercise. The use of a noninvasive remote HR monitor system allowed assessment of exercise responses in the field, and the results suggest that both the HRR during warm-up period and HRmax may be useful performance indicators in Jeju horses.

• The Korean Journal of Pain
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• v.19 no.2
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• pp.202-206
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• 2006

Background: Stellate ganglion block (SGB) might be associated with changes in the blood pressure (BP) and heart rate (HR). The heart rate variability (HRV) shows the balance state between sympathetic and parasympathetic activities of the heart. The changes in these parameters of the HRV were studied to evaluate the possible mechanism of SGB in changing the BP. Methods: SGB was performed on 26 patients, using a paratracheal technique at the C6 level, and 8 ml of 1% mepivacaine injected. The success was confirmed by check the Horner's syndrome. The BP, HR and HRV were measured before and 5, 15, 30, 45 and 60 minutes after the SGB. Results: The increases in the BP from the baseline throughout the study period were statistically, but not clinically significant. The HR and LF/HF (low frequency/high frequency) ratio were increased at 5 and 45 min, respectively, after the administration of the SGB. In a comparison of left and right SGB, no significant differences were found in the BP, HR and HRV. A correlation analysis showed that an increased BP was significantly related with the changes in the LF/HF ratio and LF at 15 and 30 minutes, respectively, after the SGB. Dividing the patients into two groups; an increased BP greater and less than 20% of that at the baseline INC and NOT groups, respectively, hoarseness occurred more often in the INC group (P = 0.02). Conclusions: It was concluded that SGB itself does not clinically increase the BP and HR in normal hemodynamic patients. However, the loss of balance between the sympathetic and parasympathetic nerve system, attenuation of the baroreceptor reflex and hoarseness are minor causes of the increase in the BP following SGB; therefore, further studies will be required.

• The Korean Journal of Physiology
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• v.5 no.2
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• pp.29-40
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• 1971

Oxygen consumption, pulmonary ventilation, heart rate, and breathing frequency were measured on 8 men walking on a treadmill carrying load of 9 kg on hand, back, or head. Besides measurements were made on subjects carrying loads of 2.6 kg each on both feet. The speed of level walking was 4, 5, and 5.5km/hr and a fixed speed off km/hr with grades of 0, 3, 6, and 9%. Comparisons were made between free walking without load and walking with various types of loads. The following results were obtained. 1. In level or uphill walking the changes in oxygen consumption, pulmonary ventilation, breathing frequency and heart rate were smallest in back load walking, and largest in hand load walking. The method of back load was most efficient and hand load was the least efficient. The energy cost in head load walking was smaller than that of in hand load walking. It was assumed that foot load costed more energy than hand load. 2. In level walking the measured parameters increased abruptly at the speed of 5.5 km/hr. Oxygen consumption in a free walking at 4 km/hr was 11.4ml/kg b.wt., and 13.1 ml/kg b.wt. 5.5 km/hr, and in a hand load walking at 4 km/hr was 13.9, and 18.8 ml/kg b. wt. at 5.5 km/hr. 3. In uphill walking oxygen consumption and other parameters increased abruptly at the grade of 6%. Oxygen consumption at 4 km/hr and 0% grade was 11.4 ml/kg b. wt., 13.6 at 6% grade, and 16.21/kg b. wt. at 9% grade in a free walking. In back load walking oxygen consumption at 4km/hr and 0% grade was 12.3 ml/kg b.wt.,14.9 at 6% grade, and 18.7 ml/kg b.wt. In hand load walking the oxygen consumption was the greatest, namely, 13.9 at 0% grade, 17.9 at 6%, and 20.0 ml/kg b. wt. at 9% grade. 4. Both in level and uphill walking the changes in pulmonary ventilation and heart rate paralleled with oxygen consumption. 5. The changes in heart rate and breathing frequency in hand load were characteristic. Both in level and uphill walk breathing frequency increased to 30 per minute when a load was held on hand and showed a small increase as the exercise became severe. In the other method of load carrying the Peak value of breathing frequency was less than 30 Per minute. Heart rate showed 106 beats/minute even at a speed of 4 km/hr when a load was held on hand, whereas, heart rate was between, 53 and 100 beats/minute in the other types of load carriage. 6. Number of strides per minute in level walking increased as the speed increased. At the speed floater than 5 km/hr number of strides per minute of load carrying walk was greater than that of free walking. In uphill walk number of strides per minute decreased as the grade increased. Number of strides in hand load walk was greatest and back load walk showed the same number of strides as the free walk.

• The Journal of Internal Korean Medicine
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• v.18 no.2
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• pp.160-166
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• 1997

To evaluate the effect of acupuncture on the hypertension, the study was done by acupuncture on bilateral Inyong(ST9) with rats which are normal and acutely increased hypertensive. The results are as follows: 1. Under the normal condition, the acupuncture on bilateral Inyong caused a quick drop of mean arterial pressure(MAP), but heart rate(HR) was not changed significantly. 2. To increase the blood pressure, acutely epinephrine was administered and it caused a increase in both MAP and HR. With acupuncture, the MAP was decreased while HR did not show a significant change. In conclusion, the acupuncture was somewhat effective in lowering the mean arterial pressure in the rat.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.6
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• pp.75-81
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• 2010

The purpose of this study was to investigate the short-term effects of electrical massager on stress-related parameters including heart rate variability (HRV), heart rate (HR) using the photoplethysmogram (PPG) signal with motion artifact correction. Twenty healthy subjects were randomly allocated to receive a 15-min section of three types ((1) resting mode (control group), (2) light massage mode, (3) strong massage mode). Results indicated that self-report, VAS (Visual Analog Scale) significantly decreased for two massage modes after massage except control group. In strong massage mode, it was associated with significant increases in HF, but significant decreases in LF and LH/HF ratio compared with the light massage mode. For all outcomes, similar changes were not observed in the control group. Also, the result founded that mean HR of all groups decrease. We conclude that electrical massager reduces perceived stress and improves adaptive autonomic response to stress in healthy adults.

• Korean Journal of Acupuncture
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• v.20 no.3
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• pp.29-34
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• 2003

Objectives : The purpose of this study was to investigate the Effect of Acupuncture Chok-samni(ST36) on Skin temperature(ST), Galvanic skin response(GSR) and Heart rate(HR) in humans. ST36 is used in uneasiness, high fever, stroke, paralysis on oriental medicine. Methods : Subjects were 18 healthy oriental medical students volunteers(15male, 3female, mean age-28). Under sequence of ST36 acupuncture, the first group was observed ST, the second group was observed GSR and the third group was observed HR. Skin temperature was measured on Haegye acupoint(ST41) before and after acupuncture stimulation. Each test took 15minutes. This test was performed twice in order to increase the statistical authenticity. Results : Our result indicates that acupuncture stimulation of ST36 statistically decreased skin temperature on ST41. Also statistically decreased in HR. The change of GSR after ST36 acupuncture was decreased, but there is no statistical. Conclusions : These results suggested that acupuncture stimulation of ST 36 has effect on ST and HR in human body, and may be used by treatment as control the nerve system.

• Journal of Korean Academy of Nursing
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• v.38 no.5
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• pp.720-729
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• 2008

Purpose: This study investigated the preemptive analgesic effects of Morphine and Ketorolac on postoperative pain, cortisol, $O_2$ saturation and heart rate for the first 24 hr after abdominal surgery. Methods: Data collection was performed from April 1 to September 30, 2006. Forty patients undergoing a gastrectomy under general anesthesia were randomly allocated to the experimental or control group. The experimental group (20 patients) was administered Morphine and Ketorolac approximately 1 hr prior to skin incision, but the control group (20 patients) was administered Morphine and Ketorolac at peritoneum closure through a patient-controlled analgesia (PCA) pump. Postoperative pain, blood pressure, heart rate, cortisol, $O_2$ saturation, frequency of the PCA button pressed and doses of additional analgesics were observed through post operative 24 hr. Collected data was analyzed using t-test, $X^2$ test, repeated measures ANOVA, and Bonferroni methods. Results: Postoperative pain, cortisol, the frequency of PCA button pressed, and dose of additional analgesics of the experimental group were significantly lower than the control group. There were no statistical differences in blood pressure, heart rate and $O_2$ saturation between the experimental group and control group. Conclusions: We concluded that administration of morphine and ketorolac at 1 hr prior to skin incision resulted in decreasing postoperative pain, but it didn't affect blood pressure, heart rate or $O_2$ saturation for 24 hr after abdominal surgery.