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1.
Hygriv B Rao Raghu Krishnaswami Sharada Kalavakolanu Narasimhan Calambur 《Indian pacing and electrophysiology journal》2010,10(3):115-121
Background
Assessment of ventricular dyssynchrony in patients with heart failure is used for selecting candidates for cardiac resynchronization therapy (CRT). The patterns of regional distribution of dyssynchrony in a population with LBBB with and without heart failure have not been well delineated. This aspect forms the object of the study.Methods
Tissue Doppler Imaging (TDI) data of consecutive patients with heart failure and LBBB (Group A) was compared with those with LBBB and normal LV function (Group B). All patients had standard 2D-echocardigraphic examination and TDI. Tissue velocity curves obtained by placing sample volumes in opposing basal and mid segments of septal, lateral, inferior, anterior and posterior walls were analyzed. Inter ventricular dyssynchrony (IVD) was assessed by the difference between aortic and pulmonary pre ejection intervals. LV dyssynchrony (LVD) was assessed by the difference in times to peak velocity. A delay of ≥ 40 msec was considered significant for presence of IVD and LVD.Results
There were 103 patients in Group A and 25 in Group B. The mean QRS duration and PR intervals respectively were 146 ± 25 vs. 152±20 msec and 182± 47 vs. 165±36 msec. (p=NS) LVEF in the 2 groups were (32 ± 6 % vs. 61± 11%; p< 0.01). Prevalence of dyssynchrony in the HF group compared to Group B was 72% vs. 16%, (P< 0.01). Lateral wall dyssynchrony in the 2 groups was 37% vs. 0% (p< 0.01) while septal dyssynchrony was 16% vs. 16% (p- NS).Conclusions
72% of heart failure patients with LBBB have documented dyssynchrony on TDI, which has a heterogeneous regional distribution. Dyssynchrony may be seen in LBBB and normal hearts but it is does not involve the lateral wall. Septal dyssynchrony in heart failure patients may not have the same significance as lateral wall delay. 相似文献2.
Beatrice Brembilla-Perrot Pierre Yves Zinzius Laurent Groben Luc Freysz Lucian Muresan Jerome Schwartz Raphael P Martins Soumaya Jarmouni Ibrahim Nossier Nicolas Sadoul Hugues Blangy Arnaud Terrier De La Chaise Pierre Louis Olivier Selton Daniel Beurrier Jean Marc Sellal 《Indian pacing and electrophysiology journal》2010,10(4):162-172
Background
The results of programmed ventricular stimulation (PVS) may change after myocardial infarction (MI). The objective was to study the factors that could predict the results of a second PVS.Methods
Left ventricular ejection fraction (LVEF) and QRS duration were determined and PVS performed within 3 to 14 years of one another (mean 7.5±5) in 50 patients studied systematically between 1 and 3 months after acute MI.Results
QRS duration increased from 120±23 ms to 132±29 (p 0.04). LVEF did not decrease significantly (36±12 % vs 37±13 %). Ventricular tachycardia with cycle length (CL) > 220ms (VT) was induced in 11 patients at PVS 1, who had inducible VT with a CL > 220 ms (8) or < 220 ms (ventricular flutter, VFl) (3) at PVS 2. VFl or fibrillation (VF) was induced in 14 patients at PVS 1 and remained inducible in 5; 5 patients had inducible VT and 4 had a negative 2nd PVS. 2. 25 patients had initially negative PVS; 7 had secondarily inducible VT, 4 a VFl/VF, 14 a negative PVS. Changes of PVS were related to initially increasing QRS duration and secondarily changes in LVEF and revascularization but not to the number of extrastimuli required to induce VFl.Conclusions
In patients without induced VT at first study, changes of PVS are possible during the life. Patients with initially long QRS duration and those who developed decreased LVEF are more at risk to have inducible monomorphic VT at 2nd study, than other patients. 相似文献3.
Background
The addition of the ECG to the preparticipation examination (PPE) of high school athletes has been a topic for debate. Defining the difference between the high school male and female ECG is crucial to help initiate its implementation in the High School PPE. Establishing the different parameters set for the male and female ECG would help to reduce false positives. We examined the effect of gender on the high school athlete ECG by obtaining and analyzing ECG measurements of high school athletes from Henry M. Gunn High School.Methods
In 2011 and 2012, computerized Electrocardiograms were recorded and analyzed on 181 athletes (52.5% male; mean age 16.1±1.1 years) who participated in 17 different sports. ECG statistics included intervals and durations in all 3 axes (X, Y, Z) to calculate 12 lead voltage sums, QRS Amplitude, QT interval, QRS Duration, and the sum of the R wave in V5 and the S Wave in V2 (RS Sum).Results
By computer analysis, we demonstrated that male athletes had significantly greater QRS duration, Q-wave duration, and T wave amplitude. (P<0.05). By contrast, female athletes had a significantly greater QTc interval. (P<0.05).Conclusion
The differences in ECG measurements in high school athletes are strongly associated with gender. However, body size does not correlate with the aforementioned ECG measurements. Our tables of the gender-specific parameters can help facilitate the development of a more large scale and in-depth ECG analysis for screening high school athletes in the future. 相似文献4.
Robert L. Lux Christopher Todd Sower Nancy Allen Susan P. Etheridge Martin Tristani-Firouzi Elizabeth V. Saarel 《PloS one》2014,9(1)
Background
Precise measurement of the QT interval is often hampered by difficulty determining the end of the low amplitude T wave. Root mean square electrocardiography (RMS ECG) provides a novel alternative measure of ventricular repolarization. Experimental data have shown that the interval between the RMS ECG QRS and T wave peaks (RTPK) closely reflects the mean ventricular action potential duration while the RMS T wave width (TW) tracks the dispersion of repolarization timing. Here, we tested the precision of RMS ECG to assess ventricular repolarization in humans in the setting of drug-induced and congenital Long QT Syndrome (LQTS).Methods
RMS ECG signals were derived from high-resolution 24 hour Holter monitor recordings from 68 subjects after receiving placebo and moxifloxacin and from standard 12 lead ECGs obtained in 97 subjects with LQTS and 97 age- and sex-matched controls. RTPK, QTRMS and RMS TW intervals were automatically measured using custom software and compared to traditional QT measures using lead II.Results
All measures of repolarization were prolonged during moxifloxacin administration and in LQTS subjects, but the variance of RMS intervals was significantly smaller than traditional lead II measurements. TW was prolonged during moxifloxacin and in subjects with LQT-2, but not LQT-1 or LQT-3.Conclusion
These data validate the application of RMS ECG for the detection of drug-induced and congenital LQTS. RMS ECG measurements are more precise than the current standard of care lead II measurements. 相似文献5.
6.
Background
Implantable Cardioverter-defibrillators (ICD) reduce mortality in survivors of cardiac arrest (CA). We investigated the predictors of mortality after ICD implantation in survivors of CA.Methods
Retrospective review of clinical records and social security death index of all patients who received an ICD in a preexisting database of survivors of CA at the University of Pittsburgh Medical Center was performed. Multivariate analyses using the Cox proportional hazard model were performed with backward elimination to identify independent predictors of the time to death, and Kaplan-Meier curves were plotted.Results
Eighty patients (64 men) with a mean age of 64.4±12.5 years were followed for 4.7±2.3 years after ICD implantation. Survival rates were 93.8%, 65% and 50% at 1, 5, and 10 years, respectively. Independent predictors of time to death were determined to include age (hazard ratio (HR) = 1.91 per 10-year increase, p = 0.003), serum creatinine ≥ 1.3 mg/dL (HR = 2.56, p = 0.004), and QRS width >120 ms (HR = 5.14, p = 0.012).Conclusions
In this sample of ICD recipients secondary to CA, older age, elevated serum creatinine, and wider QRS duration were independent predictors of mortality. The presence of more than one risk factor in the same patient was associated with higher mortality rates. Whether interventions such as biventricular pacing can offset this increase risk of death warrants further investigation. 相似文献7.
Background
Recently we showed the predictive value of sum absolute QRST integral (SAI QRST) and repolarization lability for risk stratification of sudden cardiac death (SCD) in heart failure patients. The goal of this study was to compare SAI QRST and metrics of depolarization and repolarization variability in healthy men and women.Methods
Orthogonal ECGs were recorded at rest for 10 minutes in 160 healthy men and women (mean age 39.6±14.6, 80 men). Mean spatial TT′ angle, and normalized variances of T loop area, of spatial T vector amplitude, of QT interval and Tpeak-Tend area were measured for assessment of repolarization lability. Normalized variances of spatial QRS vector and QRS loop area characterized variability of depolarization. In addition, variability indices (VI) were calculated to adjust for normalized heart rate variance. SAI QRST was measured as the averaged arithmetic sum of areas under the QRST curve.Results
Men were characterized by shorter QTc (430.3±21.7 vs. 444.7±22.2 ms; P<0.0001) and larger SAI QRST (282.1±66.7 vs.204.9±58.5 mV*ms; P<0.0001). Repolarization lability negatively correlated with spatial T vector amplitude. Adjusted by normalized heart rate variance, QT variability index was significantly higher in women than in men (−1.54±0.38 vs. −1.70±0.33; P = 0.017). However, in multivariate logistic regression after adjustment for body surface area, QTc, and spatial T vector amplitude, healthy men had 1.5–3 fold higher probability of having larger repolarization lability, as compared to healthy women (T vector amplitude variability index odds ratio 3.88(95%CI 1.4–11.1; P = 0.012).Conclusions
Healthy men more likely than women have larger repolarization lability. 相似文献8.
L. Heini? R. Nikander H. Siev?nen 《Journal of musculoskeletal & neuronal interactions》2015,15(3):279-285
Objective:
To examine whether different exercise loading is associated with lumbar vertebral texture as assessed with Trabecular Bone Score (TBS).Methods:
Data from 88 Finnish female athletes and 19 habitually active women (reference group) were analyzed. Participants’ mean age was 24.3 years (range 17-40 years). Athletes were divided into five specific exercise loading groups according to sport-specific training history: high-impact (triple jumpers and high jumpers), odd-impact (soccer players and squash players), high-magnitude (power lifters), repetitive impact (endurance runners), and repetitive non-impact (swimmers). TBS-values were determined from lumbar vertebral L1-L4 DXA images. Body weight and height, fat-%, lean mass, isometric maximal leg press force, dynamic peak jumping force and lumbar BMD were also measured.Results:
Endurance runners’ mean TBS value differed significantly from all other groups being about 6% lower than in the reference group. After controlling for body height, isometric leg press force and fat-%, the variables found consistently explaining TBS, the observed between-group difference remained significant (B=-0.072, p=0.020). After controlling for BMD, the difference persisted (B=-0.065, p=0.016). There were no other significant adjusted between-group differences.Conclusion:
Exercise loading history comprising several repeated moderate impacts is associated with somewhat lower TBS, which may indicate specific lumbar microarchitecture in endurance runners. 相似文献9.
Rinaldi CA Kirubakaran S Bucknall CA Bostock J Gill JS 《Indian pacing and electrophysiology journal》2011,11(1):5-14
Background
Dual chamber pacing improves functional status and reduces left ventricular outflow tract gradients in some, but not all patients with hypertrophic cardiomyopathy (HCM) by altering ventricular depolarisation. We investigated the use of biventricular (BIV) pacing in symptomatic patients with HCM.Method
8 patients aged 58±7yrs with symptomatic HCM underwent BIV pacing. 5 patients had LVOT gradients >30mmHg. Ventricular electrodes were placed in the right ventricle (RV) and a branch of the coronary sinus. An atrial electrode was inserted to achieve BIV pacing with a short AV delay. The short-term effects of different pacing modalities were assessed using 2-D and Doppler echocardiography. Symptoms and exercise tolerance were assessed after a month of each pacing mode. Long-term follow up data was available for 5 years.Results
Baseline EF was 67±14% and mean QRS duration was 132±26msecs. BIV pacing reduced QRS duration compared to RV pacing (129±46 vs. 205±54msecs, p<0.005). Five of the seven patients had baseline LVOT gradients (mean 67±25mmHg) that decreased to 41±15mm Hg with RV pacing (p<0.01) and 25±15mmHg with BIV pacing (p<0.005). Improvements in exercise time with active pacing occurred in six out of eight patients (75%), three (37.5%) had optimal exercise times with RV pacing and three with BIV pacing. Of the three patients with short term improvements with BIV pacing, one died 4 years post implant, one deteriorated with LV dilatation and one had the system explanted for infection.Conclusion
BIV pacing showed short-term beneficial effects in some patients over and above RV pacing alone. 相似文献10.
Aim
The aim of this study was to identify adaptations in muscle activity distribution to spinal tissue creep in presence of muscle fatigue.Methods
Twenty-three healthy participants performed a fatigue task before and after 30 minutes of passive spinal tissue deformation in flexion. Right and left erector spinae activity was recorded using large-arrays surface electromyography (EMG). To characterize muscle activity distribution, dispersion was used. During the fatigue task, EMG amplitude root mean square (RMS), median frequency and dispersion in x- and y-axis were compared before and after spinal creep.Results
Important fatigue-related changes in EMG median frequency were observed during muscle fatigue. Median frequency values showed a significant main creep effect, with lower median frequency values on the left side under the creep condition (p≤0.0001). A significant main creep effect on RMS values was also observed as RMS values were higher after creep deformation on the right side (p = 0.014); a similar tendency, although not significant, was observed on the left side (p = 0.06). A significant creep effects for x-axis dispersion values was observed, with higher dispersion values following the deformation protocol on the left side (p≤0.001). Regarding y-axis dispersion values, a significant creep x fatigue interaction effect was observed on the left side (p = 0.016); a similar tendency, although not significant, was observed on the right side (p = 0.08).Conclusion
Combined muscle fatigue and creep deformation of spinal tissues led to changes in muscle activity amplitude, frequency domain and distribution. 相似文献11.
Sirin Apiyasawat Dujdao Sahasthas Tachapong Ngarmukos Pakorn Chandanamattha Khanchit Likittanasombat 《Indian pacing and electrophysiology journal》2014,14(1):4-11
Background
Fragmented QRS (fQRS) has been shown to be a marker of local myocardial conduction abnormalities and a predictor of cardiac events in selected populations. We hypothesized that the presence of a fQRS might predict arrhythmic events in patients who received an implantable cardioverter-defibrillator (ICD), regardless of the indications for implantation.Methods and Results
A cohort of 107 consecutive patients (mean age, 53 years; 82% male) who underwent an ICD implantation was studied. We defined fQRS, on a routine 12-lead ECG, as the presence of an additional R wave or notching in the nadir of the S wave in 2 consecutive leads corresponding to a major coronary artery territory. In the presence of bundle branch block, more than 2 notches in the R or S waves in 2 consecutive leads were required to characterize fQRS. Patients were followed for 21.3±23 months for appropriate ICD therapy (antitachycardia pacing and/or shock). ICDs were implanted predominantly in patients with ischemic cardiomyopathy (N=45, 42.1%), followed by Brugada syndrome (N=26, 24.3%). fQRS presented in 42 patients (39.3%). During follow-up, patients with fQRS received more appropriate ICD therapy than those without fQRS (45.2% vs. 10.8%, P<0.0001). After adjustment for covariates, fQRS remained an independent predictor for appropriate ICD therapy (hazard ratio=5.32, 95% confidence interval=2.11-13.37, P<0.0001).Conclusion
The presence of fQRS appeared to be directly associated with appropriate ICD therapy. 相似文献12.
Sushma Tejwani Rohit Shetty Mathew Kurien Shoruba Dinakaran Arkasubhra Ghosh Abhijit Sinha Roy 《PloS one》2014,9(8)
Purpose
In this study, spectral analysis of the deformation signal from Corvis-ST (CoST) and reflected light intensity from ocular response analyzer (ORA) was performed to evaluate biomechanical concordance with each other.Methods
The study was non-interventional, observational, cross-sectional and involved 188 eyes from 94 normal subjects. Three measurements were made on each eye with ORA and CoST each and then averaged for each device. The deformation signal from CoST and reflected light intensity (applanation) signal from ORA was compiled for all the eyes. The ORA signal was inverted about a line joining the two applanation peaks. All the signals were analyzed with Fourier series. The area under the signal curves (AUC), root mean square (RMS) of all the harmonics, lower order (LO included 1st and 2nd order harmonic), higher order (HO up to 6th harmonic), CoST deformation amplitude (DA), corneal hysteresis (CH) and corneal resistance factor (CRF) were analyzed.Results
The device variables and those calculated by Fourier transform were statistically significantly different between CoST and ORA. These variables also differed between the eyes of the same subject. There was also statistically significant influence of eyes (left vs. right) on the differences in a sub-set of RMS variables only. CH and CRF differed statistically significantly between the eyes of subject (p<0.001) but not DA (p = 0.65).Conclusions
CoST was statistically significantly different from ORA. CoST may be useful in delineating true biomechanical differences between the eyes of a subject as it reports deformation. 相似文献13.
A.M.W. van Stipdonk M. Mafi Rad J.G.L.M. Luermans H.J. Crijns F.W. Prinzen K. Vernooy 《Netherlands heart journal》2016,24(1):58-65
Background
Delayed left ventricular (LV) lateral wall activation is considered the electrical substrate that characterises patients suitable for cardiac resynchronisation therapy (CRT). Although typically associated with left bundle branch block, delayed LV lateral wall activation may also be present in patients with non-specific intraventricular conduction delay (IVCD). We assessed LV lateral wall activation in a cohort of CRT candidates with IVCD using coronary venous electroanatomical mapping, and investigated whether baseline QRS characteristics on the ECG can identify delayed LV lateral wall activation in this group of patients.Methods
Twenty-three consecutive CRT candidates with IVCD underwent intra-procedural coronary venous electroanatomical mapping using EnSite NavX. Electrical activation time was measured in milliseconds from QRS onset and expressed as percentage of QRS duration. LV lateral wall activation was considered delayed if maximal activation time measured at the LV lateral wall (LVLW-AT) exceeded 75 % of the QRS duration. QRS morphology, duration, fragmentation, axis deviation, and left anterior/posterior fascicular block were assessed on baseline ECGs.Results
Delayed LV lateral wall activation occurred in 12/23 patients (maximal LVLW-AT = 133 ± 20 ms [83 ± 5 % of QRS duration]). In these patients, the latest activated region was consistently located on the basal lateral wall. QRS duration, and prevalence of QRS fragmentation and left/right axis deviation, and left anterior/posterior fascicular block did not differ between patients with and without delayed LV lateral wall activation.Conclusion
Coronary venous electroanatomical mapping can be used at the time of CRT implantation to determine the presence of delayed LV lateral wall activation in patients with IVCD. QRS characteristics on the ECG seem unable to identify delayed LV lateral wall activation in this subgroup of patients. 相似文献14.
Dib C Prasad A Friedman PA Ahmad E Rihal CS Hammill SC Asirvatham SJ 《Indian pacing and electrophysiology journal》2008,8(3):182-192
Objectives
We sought to determine the frequency and outcomes with symptomatic arrhythmia in patients with apical ballooning syndrome (ABS).Methods
A retrospective review of the Mayo Clinic Angiography database was conducted to identify patients who met the Mayo criteria for ABS. Patients with documented arrhythmias formed the study group, and 31 randomly selected patients with ABS but without arrhythmia formed the control group.Results
Out of 105 patients identified with ABS, 6 (5.7%) women aged 69 +/- 9 years experienced significant arrhythmia (ventricular fibrillation, asystole), 2 patients died, and 1 required permanent pacemaker implantation. When compared with controls, the study group showed no significant difference with respect to ECG characteristics (QT, QRS duration or axis) except for R-R interval variability (see comments below) (30.6±6 vs 14.5±17 p = 0.0004), QTc, and P-R interval. Patients without arrhythmia were more likely to be on beta-blocker therapy than the study population (33% vs 80.6% p = 0.02).Conclusion
Life-threatening arrhythmia is uncommon (5.7%) with ABS despite marked, structural abnormalities. When arrhythmias do occur, the outcome is poor. Prominent variability in R-R intervals appears to be predictive of significant arrhythmias in ABS. The role of beta-blocker therapy in preventing arrhythmia with ABS requires further investigation. 相似文献15.
Objectives:
To examine the relationship between the biceps brachii muscle innervation zone (IZ) width and the mean muscle fiber conduction velocity (MFCV) during a sustained isometric contraction.Methods:
Fifteen healthy men performed a sustained isometric elbow flexion exercise at their 60% maximal voluntary contraction (MVC) until they could not maintain the target force. Mean MFCV was estimated through multichannel surface electromyographic recordings from a linear electrode array. Before exercise, IZ width was quantified. Separate non-parametric one-way analyses of variance (ANOVAs) were used to examine whether there was a difference in each mean MFCV variable among groups with different IZ width. In addition, separate bivariate correlations were also performed to examine the relationships between the IZ width and the mean MFCV variables during the fatiguing exercise.Results:
There was a significant difference in the percent decline of mean MFCV (%ΔMFCV) among groups with different IZ width (χ2 (3)=11.571, p=0.009). In addition, there was also a significant positive relationship between the IZ width and the %ΔMFCV (Kendall’s tau= 0.807; p<0.001).Conclusions:
We believe that such relationship is likely influenced by both muscle fiber size and the muscle fiber type composition. 相似文献16.
Predrag Noveski Svetlana Madjunkova Emilija Sukarova Stefanovska Nadica Matevska Geshkovska Maja Kuzmanovska Aleksandar Dimovski Dijana Plaseska-Karanfilska 《PloS one》2016,11(1)
Background
Although age-related loss of chromosome Y (LOY) in normal hematopoietic cells is a well-known phenomenon, the phenotypic consequences of LOY have been elusive. However, LOY has been found in association with smoking, shorter survival and higher risk of cancer. It was suggested that LOY in blood cells could become a predictive biomarker of male carcinogenesis.Aims, Methods & Findings
To investigate the association of LOY in blood cells with the risk for development of colorectal (CC) and prostate cancers (PC), we have analyzed DNA samples from peripheral blood of 101 CC male patients (mean age 60.5±11.9 yrs), 70 PC patients (mean age 68.8±8.0 yrs) and 93 healthy control males (mean age 65.8±16.6 yrs). The methodology included co-amplification of homologous sequences on chromosome Y and other chromosomes using multiplex quantitative fluorescent (QF) PCR followed by automatic detection and analysis on ABI 3500 Genetic Analyzer. The mean Y/X ratio was significantly lower in the whole group of cancer patients (0.907±0.12; p = 1.17x10-9) in comparison to the controls (1.015±0.15), as well as in CC (0.884±0.15; p = 3.76x10-9) and PC patients (0.941±0.06; p = 0.00012), when analyzed separately. Multivariate logistic regression analysis adjusting for LOY and age showed that LOY is a more significant predictor of cancer presence than age, and that age probably does not contribute to the increased number of subjects with detectable LOY in cancer patients cohort.Conclusion
In conclusion, our results support the recent findings of association of LOY in blood cells with carcinogenesis in males. 相似文献17.
Alexander Berkowitsch Thomas Neumann Malte Kuniss Roland Brandt Sergej Zaltsberg Heinz F Pitschner 《Indian pacing and electrophysiology journal》2009,9(3):138-150
Background
Paroxysmal atrial fibrillation (PAF) is defined as recurrent AF terminating spontaneously within 7 days. This definition allows the consideration of any AF occurrence lasting < 7 days as paroxysmal, irrespective of the frequency and duration of episodes. The aim of this study was to investigate symptomatic AF burden (AFB) defined as total duration of symptomatic AF episodes within 3 months prior to abalation, for prediction of outcome after pulmonary vein isolation (PVI).Methods
A total of 320 consecutive patients with symptomatic AF (PAF=244, men=214, age=58 y) were enrolled. AFB in patients with PAF was defined as time spent in AF within 3 months prior to PVI. After the AFB cut-off point was optimized at 500 h, patients with PAF were categorized into 2 groups: Group 1 - patients with AFB< 500 h (n=192), Group 2 - patients with AFB≥ 500 h (n=52). Patients with persistent AF (PersAF, n = 76) comprised control group (Group 3). PVI was performed either with irrigated tip catheter (n=215) or using cryoballoon (n=105). The endpoint of study was first documented recurrence of AF >30 sec.Results
Symptomatic AFB was found to be appropriate for prediction of outcome after PVI. The freedom from AF within 2 years was observed in 69%, 31%, and 43% patients in Group 1, 2 and 3, respectively (Group 1 vs. Group 2, p < .001; Group 1 vs. Group 3, p< .001; Group 2 vs. Group 3, p = 0.46).Conclusions
Low AFB < 500 h /3 months was associated with better outcome after PVI. Patients with PAF and high AFB should be treated as patients with PersAF. 相似文献18.
M. Loretto Munoz Arie van Roon Harri?tte Riese Chris Thio Emma Oostenbroek Iris Westrik Eco J. C. de Geus Ron Gansevoort Joop Lefrandt Ilja M. Nolte Harold Snieder 《PloS one》2015,10(9)
Objectives
In order to investigate the applicability of routine 10s electrocardiogram (ECG) recordings for time-domain heart rate variability (HRV) calculation we explored to what extent these (ultra-)short recordings capture the “actual” HRV.Methods
The standard deviation of normal-to-normal intervals (SDNN) and the root mean square of successive differences (RMSSD) were measured in 3,387 adults. SDNN and RMSSD were assessed from (ultra)short recordings of 10s(3x), 30s, and 120s and compared to 240s–300s (gold standard) measurements. Pearson’s correlation coefficients (r), Bland-Altman 95% limits of agreement and Cohen’s d statistics were used as agreement analysis techniques.Results
Agreement between the separate 10s recordings and the 240s-300s recording was already substantial (r = 0.758–0.764/Bias = 0.398–0.416/d = 0.855–0.894 for SDNN; r = 0.853–0.862/Bias = 0.079–0.096/d = 0.150–0.171 for RMSSD), and improved further when three 10s periods were averaged (r = 0.863/Bias = 0.406/d = 0.874 for SDNN; r = 0.941/Bias = 0.088/d = 0.167 for RMSSD). Agreement increased with recording length and reached near perfect agreement at 120s (r = 0.956/Bias = 0.064/d = 0.137 for SDNN; r = 0.986/Bias = 0.014/d = 0.027 for RMSSD). For all recording lengths and agreement measures, RMSSD outperformed SDNN.Conclusions
Our results confirm that it is unnecessary to use recordings longer than 120s to obtain accurate measures of RMSSD and SDNN in the time domain. Even a single 10s (standard ECG) recording yields a valid RMSSD measurement, although an average over multiple 10s ECGs is preferable. For SDNN we would recommend either 30s or multiple 10s ECGs. Future research projects using time-domain HRV parameters, e.g. genetic epidemiological studies, could calculate HRV from (ultra-)short ECGs enabling such projects to be performed at a large scale. 相似文献19.
H. Siev?nen P. Zagorski B. Drozdzowska H. V?h?-Ypy? D. Boron P. Adamczyk W. Pluskiewicz 《Journal of musculoskeletal & neuronal interactions》2015,15(3):264-269
Objective:
To evaluate the influence of elite-level alpine skiing on athletes’ skeleton.Methods:
Thirteen professional alpine skiers (9 males and 4 females with mean age of 22.6 years) and their age- and height matched control subjects were measured with dual energy X-ray absorptiometry (total body, lumbar spine, proximal femur, forearm) and quantitative ultrasound (hand).Results:
After adjusting for sex, age, weight and height, between-group differences were 15% (p=0.012) for the lumbar spine, 14% (p=0.022) for the femoral neck, 10% (p=0.051) for the total hip, and 11% (p=0.001) for the total body favoring the alpine skiers. However, after controlling for total body lean mass (~muscle mass), the group-differences lost their statistical significance, the borderline 10% difference (p=0.051) in femoral neck BMD excluded.Conclusion:
Factors contributing to the alpine skiers’ higher BMD may not only include the greater muscle mass (~stronger muscles) of these athletes but also a large number of impacts and possibly other high-frequency features in external loading generated by the high-speed skiing performance. 相似文献20.