One-minute Interval Research Articles

THE ORTHOSTATIC HYPOTENSION AS A PREDICTOR OF CLINIC COMPLICATIONS IN HYPERTENSIVE PATIENTS WHO UNDERWENT NON-CARDIAC SURGERIES

Objective: Evaluate preoperative orthostatic hypotension as a predictor of clinical complications after non-cardiac surgery in hypertensive patients. Design and method: This was a prospective observational study. We included adult hypertensive patients scheduled for elective noncardiac surgery in an university hospital. Patients with heart failure or end-stage renal disease were excluded, as well as those that were not able to stand up. Each patient had their blood pressure measured in the ward before surgery. Blood presure was measured 3 times with a one-minute interval between measurements in supine position and was repeated after three minutes in orthostatic position. We defined orthostatic hypotension as a reduction in systolic blood pressure >20 mmHg. All patients in the study were followed up until discharge from hospital. We used student t test, chi-square and Pearson correlation coefficient as appropriate for statistical analysis. Possible confounding factors were controlled by logistic regression analysis. Results: We included 146 patients. Mean age was 63 years and 48% (70) were female. Most common surgeries were gastrointestinal and urologic. Orthostatic hypotension occurred in 5.2% (7) of patients and mean blood pressure drop was 28 mmHg. No patients died but clinical complications occurred in 46% (67); the most common were infections and acute renal failure. After logistic regression, age, race and orthostatic hypotension remained significant predictors of clinical complications. Conclusions: Orthostatic hypotension is a predictor of clinical complications after elective noncardiac surgeries in hypertensive patients.

Acute effects of different rest period between sets on neuromuscular bench press performance

Introduction: Manipulation of resistance training variables allows the maintenance the performance of the proposed exercise. Objetctive: To evaluation the acute effects of different rest intervals on maximum repetition performance, perceived exertion, and fatigue index on bench press. Methods: Following ten-repetition maximum testing and retesting, four experimental sessions involved seven bench press sets to concentric failure with the goal of completing the maximum number of repetitions, which included: 1) one-minute rest interval between sets (P1), 2) two-minute rest interval between sets (P2), three-minute rest interval between sets (P3), and five-minute rest interval between sets (P5). Results: A main result was observed in maximum repetition performance for all sets (p0.001). In the fatigue index, only P3 and P5 showed significant differences compared to all other protocols (p0.001). Besides, the perceived exertion shows a similar trend to fatigue index for longer rest intervals. Conclusion: Reducing the maximum repetition performance in shorter intervals is an important tool for reducing the total workout time.

One-minute time interval estimation as a novel potent indicator of need for help in cancer patients prior to starting chemotherapy.

e23161 Background: Perception of time strongly correlates with people’s current emotional state. Our study explored the potential relationship between the time estimation and the need of help in cancer patients prior to starting chemotherapy. Methods: Time estimation was assessed in 375 chemonaïve patients with solid tumors by evaluating each subject’s prospective estimation of how fast one minute passed compared to the actual time. The median value (40 sec) of time estimation was used to stratify the patients into two categories of fast and slow time estimation. The National Comprehensive Cancer Network Distress Thermometer and Problem List were used at the beginning of treatment to evaluate levels of distress and patients’ concerns. Additional question was asked “Do you need help?”. Results: Patients who reported the need of help were 134 (35.7%). The need of help correlated with fast time estimation, high level of distress and younger age (< 65y). Patients who reported a need of help estimated time significantly faster than those who did not report it (37.2±15.5 vs 42.7±17.2; p = 0.004). ROC analysis revealed that at the optimal cutoff value of time estimation, patients who reported a need of help and those who did not can be discriminated with an AUC = 0.59 (95% CI: 0.53-0.65, p = 0.003) and with a sensitivity of 61.9% and a specificity of 50.6%. Moreover, in a multivariate logistic regression model, fast time estimation was an independent predictor of reporting the need of help (OR 1.59; 95% CI 1.02-2.45; p = 0.04). Conclusions: Time estimation is a novel potent indicator for the need of help in cancer patients. This test is an easily performed, time-saving and nonintrusive ultrashort screening tool for the need of help that is even suitable for patients who are not willing to reveal their need of help via direct questionnaires.

Applicability of Smartphone for Dynamic Postural Stability Evaluation.

The purpose of this study was to determine the accuracy of smartphone's gyroscope for dynamic postural stability among young healthy adults. The research included convenience sample of 85 healthy adults—37 women (mean age 22.1±1.6, body height 167.2±7.0) and 48 men (mean age 22.4±1.7, body height 176.1±13.8). In order to assess the accuracy of stabilometric measurement recorded by mobile phone, the raw data obtained at the same time by Sigma Balance Platform and Smartphone (SP) were correlated. Two thirty-second trials with one-minute interval break were performed (first in the frontal plane and second in the sagittal plane). A total of 170 measurements of postural stability were recorded (85 in frontal and 85 in the sagittal plane). The following parameters were included: the path of the stabilogram (in the case of SP, angular path) and the variation of the swing (standard deviation of the horizontal deflection of the platform). The results have shown strong and significant relationship between body sway variability measured by Sigma platform and smartphone in frontal (r=0.997) and sagittal (r=0.990) plane. For the geometric center of the platform and angular path distances, the correlation coefficient was also statistically significant and high, considering both lateral (r=0.999) and anterior-posterior sway (r=0.981). Our research shows that smartphones with gyroscope have potential for accurate assessment of postural balance, as an alternative for expensive and specialized equipment.

Assessing the Profitability of Timely Opening Range Breakout on Index Futures Markets

This paper presents a timely open range breakout (TORB) strategies for index futures market trading via using one-minute intraday data. We observe that the trading volumes and fluctuations in returns on each one-minute interval of trading hours in the futures markets reach their peaks at the opening and closing of the underlying stock markets. With these observations, we align the active hours of an index futures market with its underlying stock market and test the proposed TORB strategies on the DJIA, SP the best performance, 20.28% annual returns at a $p$ -value of $3.1\times 10^{-5}$ %, is reached in the TAIEX. For each market, we also find the best probing time, which is relatively short in the U.S. market and relatively long in Asian markets. Furthermore, we conduct experiments on a TAIEX futures transaction dataset to analyze the relationship between the TORB signals and trader behavior, and find that the TORB signals are in the same direction as institutional traders, especially foreign investment institutions.

An optimal strategy for prediction of sudden cardiac death through a pioneering feature-selection approach from HRV signal

Background and objectiveTaking into consideration the critical importance of Sudden cardiac death (SCD), as it could be the first and the last heart condition to be diagnosed in a person while continuing to claim millions of lives around the world, prediction of sudden cardiac death has increasingly been regarded as a matter of substantive significance. This study does not seek to once again define features to predict and detect SCD, as there already has been adequate discussion addressing feature extraction in our previous works and other recent studies. What seems to be lacking attention is the need for an appropriate strategy to manage the extracted features to such an extent that the best classification is presented. To this end, deploying a suitable tactic to select extracted features could bring about outstanding results compared to other works in the literature. MethodsThis research has accordingly applied a novel and automated approach to Local Feature Subset Selection through the most rigorous methodologies, which have formerly been developed in previous works of this team, for extracting features from nonlinear, time-frequency and classical processes. We are therefore enabled to select features that differ from one another in each minute before the incident through the agency of optimal feature selection in each one-minute interval of the signal. ResultsUsing the proposed algorithm, SCD can be predicted 13 min before the onset, thus, better results are achieved compared to other techniques proposed in this field. Additionally, through defining a Utility Function and employing statistical analysis the alarm threshold has been effectively determined as 84% for the prediction accuracy. Having selected the best combination of features, based on their ability to generate the highest classification accuracy, the two classes are classified by means of the Multilayer Perceptron (MLP), K- Nearest Neighbor (KNN) the Support Vector Machine (SVM), and the Mixture of Expert (ME) classifier. The Mixture of Experts classification yielded more precise class discrimination than other well-known classifiers. The performance of the proposed method was evaluated using the MIT-BIH database which led to sensitivity, specificity, and accuracy of 84.24%, 85.71%, and 82.85%, respectively for thirteen one-minute. ConclusionsThe outcome of the obtained prediction would be analyzed and compared to other results. The most applicable and effective features would subsequently be presented according to the number of times they have been chosen. Finally, principal features in each time interval are discussed and the importance of each type of processing will be drawn into focus. The results indicate the significant capacity of the proposed method for predicting SCD from Electrocardoigram (ECG) signals as well as selecting the appropriate processing method at any time before the incident.

Does typical weather data allow accurate predictions of daylight quality and daylight-responsive control system performance

Though Typical Meteorological Year (TMY) data is widely used for predicting daylight quality and daylight-responsive control system performance, few studies investigated whether the predictions were accurate. In this study, daylight simulation was performed for a real space using the TMY data and an actual local weather data with a one-minute interval. The former was used to predict the daylight quality, to design a closed-loop daylight-responsive dimming control system, to select the calibration hours, and to predict the control system performance; the latter was used to characterize the actual daylight quality and control system performance. Though the actual weather conditions can provide 30% higher daylight levels to the space, which seemed to suggest a potential to achieve a greater energy saving, none of the existing CBDM measures suggested such a difference. The TMY data was used to design a closed-loop dimming control system, to select the appropriate weather conditions for system calibration, and to predict the energy saving of the system by limiting the occurrence of over-dimming below 2% of the occupied hours. It was found the predicted energy saving was generally accurate if the system calibration was performed when the weather conditions were similar to those identified using the TMY data. When the calibration was performed under the inappropriate weather conditions, the system achieved lower energy saving and had a much frequent occurrence of over-dimming conditions. In addition, performing the system calibration under the weather conditions that resulted in higher photosensor signal to workplane illuminance ratios may be helpful to reduce the occurrence of over-dimming conditions caused by the larger variation of the weather conditions in reality.

A Note on Intraday Event Studies

We investigate the specification and power of intraday event study test statistics. Mean, market, and matched firm models generate well-specified return results for a range of intervals up to 60 min around the event. These models detect return shocks equivalent to one spread in one-minute interval data and three spreads in longer intervals. Researchers using intraday return event studies can, therefore, be confident in their robustness. Some volume event study approaches have reasonable power but they are not generally well specified, while a matched-firm approach gives the best combination of specification and power for spread event studies.

One-minute time interval estimation as a novel ultrashort tool for distress screening.

Our study explores the potential relationship between time estimation and level of distress in cancer patients prior to starting chemotherapy. Time estimation was assessed in 262 chemonaïve patients with solid tumors by evaluating each subject's prospective estimation of how fast 1min passed compared to the actual time. The median value (40s) of time estimation was used to stratify the patients into two categories of fast and slow time estimation. The National Comprehensive Cancer Network Distress Thermometer was used at the beginning of treatment to evaluate levels of distress. Patients scoring 4 or above (51.9%) were regarded as having high levels of distress. The pattern of the time estimation distributions significantly changed according to the level of distress. Patients with a fast time estimation had significantly higher levels of distress (4.55 ± 3.1) than patients with a slow time estimation (3.3 ± 2.9) (p = 0.001). ROC analysis revealed that at the optimal cutoff value of time estimation, patients with low and high distress levels can be discriminated with an AUC = 0.60 (95% CI: 0.53-0.67, p = 0.005) and with a sensitivity of 62.5% and specificity of 53.2%. Moreover, in a multivariate logistic regression model, fast time estimation was an independent predictor of high levels of distress. Time estimation is a novel potent indicator of high levels of distress in cancer patients. This test is an easily performed, time-saving, and nonintrusive ultrashort screening tool that is even suitable for patients who are not willing to reveal their level of distress via direct questionnaires.

Impact of Resistance Exercise under Hypoxia on Postexercise Hemodynamics in Healthy Young Males.

We investigated the effects of resistance exercise under hypoxia on postexercise hemodynamics in eight healthy young males. The subjects belonged to a track & field club (sprinters, hurdlers, and long jumpers) and engage in regular physical training (1-2 h per day, 3-5 days per week). Each participant performed eight sets of bilateral leg squats with a one-minute interval under normoxia (room air) and hypoxia (13 % FiO2). During a 60-minute recovery, we set normoxic condition either after normoxic or hypoxic exercise. These two experimental protocols (normoxia and hypoxia) were performed in a random order with a one-week washout period. The leg squat exercise consists of 50 % 1-RM (14 repetitions) × 5 sets and 50% 1-RM (repetitions max; 7 repetitions) × 3 sets. The resting period between each set was 1 min, and a total of 91 repetitions were performed. Blood pressure, heart rate (HR), and several biomarkers were measured pre- and postexercise. The mean arterial pressure (MAP) significantly decreased after exercise compared to the pre-exercise values under both conditions (P < 0.05). The MAP at 20 and 30 min of recovery in hypoxia was significantly lower than in normoxia (P < 0.05, respectively). The antidiuretic hormone significantly increased after 60 min of recovery in both conditions; moreover, the values in hypoxia were significantly higher than those in normoxia (P < 0.05). The delta changes in MAP from baseline (pre-exercise) were significantly related to changes in HR from baseline in normoxia (r = 0.560, P < 0.001) but not in hypoxia. These results suggest that the hypoxic condition elicits greater hypotension after resistance exercise in comparison to normoxia. Moreover, the underlying mechanisms for the attenuation of hypotension after resistance exercise may differ between normoxia and hypoxia.

Conceptual Framework of Modelling for Malaysian Household Electrical Energy Consumption using Artificial Neural Network based on Techno-Socio Economic Approach

The residential sector was one of the contributors to the increase in the world energy consumption and CO2 emission due to the increase population, economic development, and improved living standard. Developing a reliable model of electrical energy consumption based on techno-socio economic factors was challenging since many assumptions need to be considered. Over the past decade, bottom-up approaches such as multi-linear regression, artificial neural network (ANN), and conditional demand analysis were used for developing mathematical models to investigate interrelated characteristics among techno-socio economic factors. However, the existing models mostly were focused on countries that had different socio-economic level and cultures from the developing countries of the Association of Southeast Asian Nations. Similar studies in that tropical region were very scarce and only limited for linear modelling under the conditions of techno-socio economic factors. In this study, we proposed ANN for developing a model of electrical energy consumption based on techno-socio economic factors for a tropical region, Malaysia. In order to develop the model, quantitative measurement and qualitative assessment were required. The quantitative measurement was based on the monitoring of total electrical energy consumption with a one-minute interval. In contrast, the qualitative assessment utilized a questionnaire survey to assess household characteristics based on techno-socio economic parameters. The objective of this paper was to propose a conceptual framework of the estimation model for household electrical energy consumption with the consideration of techno-socio economic factors using ANN.

FIVE CONSECUTIVE OFFICE BLOOD PRESSURE MEASUREMENTS VERSUS CURRENT PRACTICE. HOW AGE, GENDER, DIABETES AND HYPERTENSION AFFECT BLOOD PRESSURE

Objective: Recently, new data from trials conducted on hypertension have been surging, leading to changes in the management of patients with arterial hypertension, and subsequently giving rise to modifications of practice guidelines. Yet, there is no consensus on the number of readings that should be considered to measure the accurate BP. The study aimed to determine the impact of age, gender, diabetes mellitus and hypertension on the systolic (SBP) and diastolic blood pressure (DBP) variability patterns in cardiac patients. Moreover, we highlighted the variability that occurs in percentage of patients diagnosed with hypertension according to different current guidelines Vs using mean of 5 consecutive BP readings.Methods: 1389 cardiac patients (median age, 54 (18, 87 y)) presenting at Alhyatt Heart and Vascular Center were studied. Five consecutive blood pressure measurements were taken, with one-minute interval. High SBP and DBP were classified according to the mean of the 5 readings as SBP >140 and DBP >90 mmHg according to different guidelines and SBP>130 and DBP>80 as per to new AHA/ACC cutoffs. Young subjects were defined as those <50y of age. A decrease in BP over 5 readings were defined as a difference between BP-reading 5 (R5) and R1 of -1 mmHg or more, while an increase was defined as R5-R1 ≥ 1 mmHg. Result: Number of patients diagnosed with hypertension varied among different guidelines and protocols, we found that this number was significantly altered when comparing different guidelines to the mean of five BP readings as follows: 560 (40.3%) patient as per to ESC (P < 0.001), 518 (37.3%) patient as per to CHEP (p < 0.001), 862 (62%) patients according to new AHA/ACC (p < 0.001). SBP decreased from R1 to R5 in 66% of patients by a mean of 6 mmHg. The decrease was greater in younger subjects (8 mmHg) compared to older patients (4 mmHg, P < 0.001). Sex, age, DM and hypertension significantly affected the SBP pattern. DBP declined in 55% of the population (mean decrease = 3 mmHg). Only hypertension and gender, but not DM or age affected the DBP pattern. The second reading of the SBP was notably higher than the other readings in hypertensive patients, diabetic patients, and older individuals with an average of 3–5 mmHg. Conclusion: Subject characteristics such as age, gender, DM and HTN have an impact on blood pressure which might alter the diagnosis of hypertension. The study suggests that relying on the average of 5 BP measurements is more appropriate as the second reading often shows the greatest divergence based on subject characteristics and because 5 readings reflects an individual's daily life blood pressure variability more closely.

Comparação de dois critérios de classificação de jogadores de futebol profissional da assimetria lateral de força dos membros inferiores

Prospective studies have indicated that assessing muscle function by the isokinetic test in the preseason is able to identify muscle strength variables that can be associated with injuries in the hamstring muscles of professional soccer players. However, the results are conflicting and could be related to the different cutoff points for the categorization of athletes in asymmetric or symmetric. Based on these conflicting results, the present study aims to: i) Identify the cutoff points of lateral asymmetry (LA) of the 95% confidence interval for the peak torque in soccer players, evaluated by the isokinetic test, taking into consideration the mean population value; ii) Compare LA between 15% cutoff point proposed in literature and the upper limit of 95% confidence interval (UP) of the study population. Sixty-four professional soccer players performed five knee flexion and extension repetitions at rate of 60°/s, with a one-minute interval. To determine the cutoff point for strength asymmetries, the UP was used, and for the purpose of diagnostic concordance of information among the different values, the McNemar’s χ² test was applied. The proportion between symmetric and asymmetric athletes was not different from the 15% cutoff point and the general population, both for knee flexors (χ² = 0.5, p = 0.250) and the knee extensors (χ² = 2.0, p = 0.125). It was concluded that the cutoff point of 15% referenced in literature for the general population provides similar diagnostic information for the classification of professional soccer players.

Performance Evaluation of Time-Frequency Distributions for ECG Signal Analysis

The non-stationary and multi-frequency nature of biomedical signal activities makes the use of time-frequency distributions (TFDs) for analysis inevitable. Time-frequency analysis provides simultaneous interpretations in both time and frequency domain enabling comprehensive explanation, presentation and interpretation of electrocardiogram (ECG) signals. The diversity of TFDs and specific properties for each type show the need to determine the best TFD for ECG analysis. In this study, a performance evaluation of five TFDs in term of ECG abnormality detection is presented. The detection criteria based on extracted features from most important ECG signal components (QRS) to detect normal and abnormal cases. This is achieved by estimating its energy concentration magnitude using the TFDs. The TFDs analyse ECG signals in one-minute interval instead of conventional time domain approach that analyses based on beat or frame containing several beats. The MIT-BIH normal sinus rhythm ECG database total records of 18 long-term ECG sampled at 128Hz have been analysed. The tested TFDs include Dual-Tree Wavelet Transform, Spectrogram, Pseudo Wigner-Ville, Choi-Williams, and Born-Jordan. Each record is divided into one-minute slots, which is not considered previously, and analysed. The sample periods (slots) are randomly selected ten minutes interval for each record. This result with 99.44% detection accuracy for 15,735 ECG beats shows that Choi-Williams distribution is most reliable to be used for heart problem detection especially in automated systems that provide continuous monitoring for long time duration.

Low-cost methodology to estimate vehicle emission factors

Road traffic emission factors (EFs) are important parameters in managing air quality. Estimation typically requires data from advanced (and expensive) monitoring systems which remain unavailable in some regions (e.g. in developing countries). In this context, the use of simpler (lower-cost) systems may be more appropriate, but it is essential to guarantee the robustness of EF estimations. This article describes a methodology designed to estimate vehicle EFs from street canyon measurements of traffic fluxes, wind speed and direction, and pollutant concentration levels by using low-cost devices, all samples at a one-minute interval. We use different moving window filters (time periods) to average the raw measurements. Applying standard multiple linear regressions (MRL) and principal component regressions (PCR), we show that there is an optimal smoothing level that best relates traffic episodes and pollutant concentration measurements. An application for PM10's EFs on four vehicle categories of Havana's fleet shows a preference for PCR over MLR techniques since it reduced the collinearity effects that appear when traffic fluxes are naturally correlated between vehicle categories. The best regression fits (R > 0.5 and standard deviation of estimates < 15%) were obtained by averaging data between 40′ and 60’; within the boundaries of 95% confidence interval motorcycles have an EF = 111.1 ± 2.7 mg km−1 veh−1; modern, light vehicles have an EF = 90.6 ± 11.2 mg km−1 veh−1; old, light vehicles have an EF = 125.4 ± 18.5 mg km−1 veh−1 and heavy vehicles have an EF = 415.1 ± 31.2 mg km−1 veh−1. We showed that upgrading old light vehicles is a promising scenario for reducing PM10 air pollution in Havana by between 10 and 17%.

Determination of Radio Environmental Level in Hydrogen (HI) Band Spectrum by using Kurtosis Analysis

The Radio Frequency Interference (RFI) nowadays becomes the serious problem and crucial issue in the radio astronomy observation. It absolutely interferes the radio astronomical lines observation in such influencing the data in radio image become worse and take part reduces the signal power level strength. In this study, the analysis has been done to investigate the radio environment level in a wide band (0-9000 MHz) and hydrogen (HI) band (1300-1500MHz) especially. The observation time is 4 hours in one-minute interval at selected sites namely KUSZA Observatory (KO), Langkawi National Observatory (LNO) and East Coast Environmental Research Institute (ESERI). The radio environment level was measured using spectrum analyser at each site. In analysis part, the kurtosis method is applied and the highest average of kurtosis values indicates the lowest of radio environment level at these sites. From obtained result, the highest average of kurtosis value in wideband obtained at ‘LNO’ which 20.33. While, the highest in average of kurtosis value in specific band was found at ‘KO’ with value of 6.06. After further analysis and included with kurtosis value, we conclude the best site of low radio environment level in HI band spectrum was found at ‘KO’ and wide band at ‘LNO’. This preliminary study is important to identify the radio environment level in radio astronomical specific band such as HI band.

U.S. Quantitative Easing Policy Effect on TAIEX Futures Market Efficiency

This paper examines the market efficiency of the Taiwan Stock Exchange Capitalization Weighted Stock Index (TAIEX) Futures after the announcement of Quantitative Easing (QE) policy. Order imbalance is used to explore the relationship between return and order imbalance. We find that under the unconditional OLS model, lagged order imbalances almost have no significantly positive predictive power for current return. Nonetheless, on the trading day after the announcement of QE 1 policy, one-minute interval data show that the lagged order imbalance has predictive power for current return. Under the conditional OLS model, the reversed relation between current return and lagged order imbalance is not universal; on the other hand, after the announcement of QE 2 policy, the reversed relation between current return and lagged order imbalance is more common. Moreover, under volatility-GARCH (1, 1), one-minute interval data shows significantly positive relation between order imbalance and volatility.

A novel approach to study the pMDI plume using an infrared camera and to evaluate the aerodynamic properties after varying the time between actuations

Plume characteristics, such as temperature and velocity, emitted from pMDIs could significantly affect the dose delivered to the lung. Currently, high speed cameras and thermocouples are used separately to evaluate these parameters. We used a low-noise infrared camera to evaluate both the temperature and velocity of the emitted plume from pMDIs. Additionally, we investigated whether the fine particle fraction (FPF) is affected when time between actuations is varied. We tested three different albuterol sulfate pMDIs: ProAir® HFA, Proventil® HFA, and Ventolin® HFA. The plume and aerodynamic characteristics from these pMDIs were evaluated, after varying the time between actuations (15, 30, 60, and 120s), using the infrared camera and a next generation impactor, respectively. The aerodynamic characteristics were evaluated with and without a valved holding chamber (VHC). ProAir HFA had the softest plume followed by Proventil HFA and Ventolin HFA. Further, Ventolin HFA was slightly cooler and had significantly lower FPF than ProAir HFA and Proventil HFA. All inhalers had higher FPF when used with VHC. Further, we observed that the time between actuations affected the FPF across pMDIs. Moreover, generalized guidelines suggesting one-minute interval between actuations for pMDIs should be reconsidered, with and without a VHC.

How to estimate heart rate from pulse rate reported by oscillometric method in atrial fibrillation: The value of pulse rate variation

ObjectivesTo evaluate whether the mean pulse rate (PR) from three oscillometric blood pressure (BP) measurements provides an accurate estimation of electrocardiogram ventricular rate (HR) in patients with permanent atrial fibrillation (AF). MethodsBP and PR were measured with an oscillometric BP device for three times with one-minute interval. Simultaneously, one-minute electrocardiogram was also recorded for three times. The first PR and HR values were recorded as PR1 and HR1, and the averages of three PR and HR values as mean PR (mPR) and mean HR (mHR). Meanwhile, the differences between the highest and lowest values among the three PR and HR were calculated as ΔPR and ΔHR. Furthermore, the patients were stratified on ΔPR into the 0–15 and >15 subgroups. ResultsA moderate positive correlation existed between PR1 and HR1 or mPR and mHR, and Bland–Altman plot also showed quite wide 95% limits between them. Meanwhile, ΔPR was significantly higher than ΔHR (12.1±8.6 vs 3.6±2.5bpm, P<0.001). However, in the 0–15 subgroup, the correlation between mPR and mHR was high (R2=0.800), and the 95% limits were only from −11.3 to 14.2bpm with a difference of 1.4bpm. The coincidence (mPR–mHR<10bpm) rate was 93.9% when PR≤80bpm, 96.3% when PR 81–100bpm, and 88.9% when PR over 100bpm. ConclusionThe average of three PR values reported by an oscillometric BP device could provide a clinically accepted estimation of mean HR of 3min in AF patients with ΔPR 0–15bpm and mean PR ≤100bpm.

In-shoe plantar pressure distribution and lower extremity muscle activity patterns of backward compared to forward running on a treadmill

ObjectiveBackward locomotion in humans occurs during leisure, rehabilitation, and competitive sports. Little is known about its general biomechanical characteristics and how it affects lower extremity loading as well as muscle coordination. Thus, the purpose of this research was to analyze in-shoe plantar pressure patterns and lower extremity muscle activity patterns for backward compared to forward running. MethodsOn a treadmill, nineteen runners performed forward running at their individually preferred speed, followed by backward running at 70% of their self-selected forward speed. In-shoe plantar pressures of nine foot regions and muscular activity of nine lower extremity muscles were recorded simultaneously over a one-minute interval. Backward and forward running variables were averaged over the accumulated steps and compared with Wilcoxon-signed rank tests (p<.05). ResultsFor backward compared to forward running, in-shoe plantar pressure distribution showed a load increase under metatarsal heads I and II, as well as under the medial midfoot. This was indicated by higher maximum forces and peak pressures, and by longer contact times. Muscle activity showed significantly higher mean amplitudes during backward running in the semitendinosus, rectus femoris, vastus lateralis, and gluteus medius during stance, and in the rectus femoris during swing phase, while significantly lower mean amplitudes were observed in the tibialis anterior during swing phase. ConclusionObservations indicate plantar foot loading and muscle activity characteristics that are specific for the running direction. Thus, backward running may be used on purpose for certain rehabilitation tasks, aiming to strengthen respective lower extremity muscles. Furthermore, the findings are relevant for sport specific backward locomotion training. Finally, results provide an initial baseline for innovative athletic footwear development aiming to increase comfort and performance during backward running.