• Journal of the Semiconductor & Display Technology
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• v.20 no.1
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• pp.7-11
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• 2021

The electrocardiogram(ECG) and heart rates are essential for diagnosing heart disease. However, conventional portable ECG devices are possible to only measure heart rates or have limitations in how and where they are measured. In this paper, a portable ECG system in which ECG waveforms and heart rates are displayed on smartphone screens is developed. A smartphone is used as display equipment instead of a computer screen for continuous monitoring. The developed ECG system filters and amplifies detected analog ECG signals. Next, it converts the amplified analog ECG signals into digital signals, then transmits to the smartphone via Bluetooth communication. This ECG system can display and store biomedical signals on a smartphone through the application. As a result, the waveform and heart rates of the developed portable ECG system has been confirmed to be similar to those of existing medical devices.

• Journal of Yeungnam Medical Science
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• v.6 no.1
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• pp.99-107
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• 1989

24-hour ambulatory ECG monitoring has been examined for the evaluation of heart rate and longest pause in 34 patients with chronic atrial fibrillation(20 patients treated with digoxin and 14 patients without treatment). Following results were obtained : 1. In 34 patients, the mean of average heart rates was $75.7{\pm}13.8$/minute, fastest heart rates $148.0{\pm}32.4$/minute, slowest heart rates $48.1{\pm}8.4$/minute, difference between fastest and slowest heart rates in individual patients $99.9{\pm}29.0$/minute and longest pauses $2.95{\pm}1.06$seconds. The longest pauses of more than 4.0 seconds occurred in 4 of the 34 patients and made an exeption of comparison groups. 2. In 27 of the 34 patients, ventricular premature contractures were developed and in 11 of 27, mainly occured less than 100/24 hours and aberrant conduction occurred in all patients. 3. In 20 patients treated with digoxin(0.25mg/day), the mean of average heart rates was $78.4{\pm}13.7$/minute, fastest heart rates $152.5{\pm}33.1$/minute, slowest heart rates $48.9{\pm}8.5$/minute, difference between fastest and slowest heart rates in individual patients $103.6{\pm}31.7$/minute and longest pauses $2.55{\pm}0.50$seconds. 4. In 10 patients without treatment, the mean of average heart rates was $78.0{\pm}10.7$/minute, fastest heart rates $154.5{\pm}26.8$/minute, slowest heart rates $50.6{\pm}7.1$/minute, difference between fastest and slowest heart rates in individual patients $103.9{\pm}22.2$/minute and longest pauses $2.66{\pm}0.39$seconds. 5. The difference of heart rates and longest pauses between patients with treatment and without treatment were statistically not significant(P>0.05). In summary, authors seemed to consider that 24-hour ambulatory ECG was useful and safe method for clinical evaluation of patients with chronic atrial fibrillation.

• Biomedical Science Letters
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• v.19 no.3
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• pp.254-260
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• 2013

The purpose of this study was to survey the effects of Karvonen exercise prescription in coronary artery disease patients reaching age-predicted maximal heart rates with the exercise stress test on hemodynamic responses and cardiorespiratory fitness. The subject group was comprised of acute coronary syndrome (ACS) patients, who were divided into the maximal heart rate (MHR) group that included those who completed the test with their heart rates reaching the number of 220-age and the maximal dyspnea (MD) group that included those who could not continue the test due to respiratory difficulty and were asked to stop the test. Both groups had the exercise stress test before and after the experiment. In the exercise stress test before the experiment, the exercise prescription intensity of Karvonen was set at the target heart rates of 50~85% with a six-week exercise monitoring arrangement. As a result, there were no interactive effects in rest heart rate (RHR) according to time and group, but interactive effects were observed in maximal heart rate (MHR) (P=0.000). Both rest systolic blood pressure (RSBP) and rest diastolic blood pressure (RDBP) had no interactive effects according to time and group. Maximal systolic blood pressure (MSBP) showed significant interactive effects according to time and group (P=0.017). Maximal diastolic blood pressure (MDBP) showed no interactive effects according to time and group, while maximal rate pressure product (MRPP) showed significant interactive effects according to time and group (P=0.003). Maximal time (MT) had no interactive effects according to time and group. $VO_{2max}$ and maximal metabolic equivalent (MMET) showed significant interactive effects according to time and group (P=0.000, P=0.002, respectively), whereas maximal respiratory exchange ratio (MRER) and maximal rating of perceived exertion (MRPE) showed no interactive effects according to time and group. The exercise test that was discontinued as the subjects reached the predicted maximal heart rates considering age did not reach the maximal exercise intensity and accordingly showed low exercise effects when applied to Karvonen exercise prescription intensity. That is, the test should keep going by monitoring cardiac events, MRER and MRPE until the heart rates exceed the predicted MHR by up to 10~12 even after the subject reaches the predicted MHR considering age in the exercise stress test.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.3
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• pp.368-374
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• 2019

Objectives: To examine the associations of borg's scale with actual heart rates of workers and energy consumption during their physical work. Methods: A total of 72 workers performing physical activities in postal service, ceramic manufacturing, and metal manufacturing participated in heart rate measurement for 1 work shift using the activity meter(A360) and responded to a borg's scale questionnaire. Results: In consistent with previous findings, we presented high correlation between borg's scale and energy consumption measures among workers performing physical activities(r=0.89) while post-work average heart rate showed nearly no correlation with post-work borg's scale (r=0.09). We proposed a set of adjustments when using borg's scale to estimate physical workload for those workers engaged in physical activities during the majority of their work shift. Conclusions: Our findings suggest that a caution should be paid to when using Borg's scale to estimate heart rates during physical activities as well as energy consumption as the product of heart rate measurements.

• Journal of Biomedical Engineering Research
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• v.35 no.6
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• pp.177-184
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• 2014

Continuous monitoring of heart rates and respiratory rates for newborns or infants is very important since the abnormal breathing and heart problems can threaten the life of newborns or infants. A noncontact baby monitoring system based on a Doppler radar and an air mattress was designed. The Doppler radar was used to acquire respiratory signals and the air mattress was employed to obtain heart rates. The performance of the designed system was evaluated using a commercialized infant simulator ($Simbaby^{TM}$) and a respiration belt transducer was used to measure respiration rates as a reference. Results for respiratory rates revealed that the correlation coefficients between I-and Q-channel and the respiration belt were 0.84 and 0.91 and the mean ${\pm}$ standard deviations of errors between them were $1.66{\pm}1.92$ (bpm) and $0.88{\pm}1.65$ (bpm). Heart rates showed that the correlation coefficient between air mattress and set value of the simulator was 0.73 and the mean ${\pm}$ standard deviation of errors between them was $1.09{\pm}3.45$ (bpm). These results indicate that the designed system holds the potential as an effective monitoring tool for continuous monitoring heart rates and respiratory rates of newborns or infants.

• Journal of Chest Surgery
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• v.44 no.6
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• pp.413-417
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• 2011

Background: Sleeve lobectomy for lung cancer in close proximity to or involving the carina is widely accepted. Operative morbidity and mortality rates, recurrence, and survival rates have varied considerably across studies. Materials and Methods: From March of 2005 to July of 2010, sleeve lobectomy was performed in 19 patients and pneumonectomy was performed in 20 patients. In this paper, the results of sleeve lobectomy and pneumonectomy for patients with lung cancer will be compared and evaluated. Results: There were no postoperative complications in either group, but there was one mortality in the pneumonectomy group. There was better preservation of pulmonary function in the sleeve lobectomy group than the pneumonectomy group (p=0.066 in FVC, p=0.019 in FEV1). The 3-year survival rates were 46.7% in the sleeve lobectomy group and 54.5% in the pneumonectomy group (p=0.505). The 3-year disease-free survival rates were 38% in the sleeve lobectomy group and 45.8% in the pneumonectomy group (p=0.200). Conclusion: Sleeve lobectomy for lung cancer showed low mortality, low bronchial anastomotic complication rates, and good preservation of pulmonary function.

• Journal of Acupuncture Research
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• v.19 no.1
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• pp.147-158
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• 2002

Objective : The aim of the present study is to investigate the effect of stimulation on different sites of the body on MBP(mean blood pressure) and HR(heart rate). Methods : Six healthy men have participated in this study. Before and after 10 min, exercise on a running machine of l0km/hr, acupressure, plain acupuncture and electroacupuncture(50Hz) stimulation was practiced on GV20, LI4, ST36, BL40 and non-acupoints on T4 and T10 respectively for 20 min. and in a control group without any treatment. The changes of MBP and HR after exercise have been observed for 20 min. at 5 minute intervals. Results : Compared with control, no significant difference was observed in research of the blood pressure measurement regardless of methods nor sites of stimulation. But there were trends of reduction in the heart rates in all experimental groups. Especially, in the group of acupressure on T10 before exercise, GV20, T10 after exercise and electroacupuncture on GV20, LI4, BL40 after exercise there was statistically significant decreases in heart rates. Conclusion : From the present experiment, it is concluded that somatic stimulation has effect on the heart rates but not on the blood pressures, and the presence of effective sites on the decreases of heart rates suggest that this effect may depend on sites of stimulation.

• Korean Journal of Applied Biomechanics
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• v.25 no.2
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• pp.141-147
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• 2015

Objective : This study aimed to understand how increased heart rates at the time of drop landing during a step test would affect biomechanical variables of the lower extremity limbs. Background : Ballet performers do more than 200 landings in a daily training. This training raises the heart rate and the fatigability of the lower extremity limbs. Ballet performance high heart rate can trigger lower extremity limb injury. Method : We instructed eight female ballet dancers with no instability in their ankle joints(mean ${\pm}$ SD: age, $20.7{\pm}0.7yr$; body mass index, $19.5{\pm}1.2kg/m^2$, career duration, $8.7{\pm}2.0yr$) to perform the drop landing under the following conditions: rest, 60% heart rate reserve (HRR) and 80% HRR. Results : First, the study confirmed that the increased heart rates of the female ballet dancers did not affect the working ranges of the knee joints during drop landing but only increased angular speeds, which was considered a negative shock-absorption strategy. Second, 80% HRR, which was increased through the step tests, led to severe fatigue among the female ballet dancers, which made them unable to perform a lower extremity limb-neutral position. Hence, their drop landing was unstable, with increased introversion and extroversion moments. Third, we observed that the increasing 80% HRR failed to help the dancers effectively control ground reaction forces but improved the muscular activities of the rectus femoris and vastus medialis oblique muscles. Fourth, the increasing heart rates were positively related to the muscular activities of the vastus medialis oblique and rectus femoris muscles, and the extroversion and introversion moments. Conclusion/Application : Our results prove that increased HRR during a step test negatively affects the biomechanical variables of the lower extremity limbs at the time of drop landing.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.8
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• pp.253-258
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• 2015

From the point of view of u-healthcare, heart rate is so useful for both illness for taking care of patients and wellness for improving the level of health and wellbeing. It is because heart rate is a significant clinical variable for all kinds of diseases as well as an indicator of the intensity of exercise. Recently, a number of various wearable heart rate monitors have been released to check people's status in the body by monitoring their heart rates. In addition, a number of smartphone applications have been released to conveniently monitor the status of exercise by using heart rate monitors. However, all of these applications are limited to a personal usage. In this paper, we will design a system to simultaneously monitor heart rates coming from multiple users in a real-time, and develop an Android application to apply the system. The application mainly features a simultaneous monitoring of heart rates coming from multiple users, allowing to be effectively applied to fitness centers.

• Korean Journal of Environment and Ecology
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• v.9 no.1
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• pp.49-55
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• 1995

To investigate the heart rate changes under the influence of physical conditions on mountain trails, heart rates of 3 subjects were recorded on 9 routes in Kyeryongsan National Park and Odaesan National Park. Maximal heart rate during uphill walking recorded between 84% and 96% to individual maximal heart rate using ergometer, thus uphill walking on mountain trail was an exhaustive exercise. The ratio of maximal heart rate during downhill walking indicated between 78% and 93% to maximal heart rate during uphill walking. And gradient of trail influenced on heart rate, but width of trail didn't. The heart rate on wooden- or stony-step-trail were rapidly increased in comparison with the heart rates on soil-trails.