bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of Cardiac Autonomic Nervous Activities by Means of ECG R‐R Interval Power Spectral Analysis and Cardiac Depolarization‐Repolarization Process
Authors: Ue Hidetoshi , Masuda Izuru , Yoshitake Yasuhide , Inazumi Takanori , Moritani Toshio
Published: October 2006

Background: Cardiac autonomic dysfunction is prevalent in diabetic patients and associated with prolongation of myocardial repolarization period. It was speculated that changes in autonomic nervous system activity, particularly the sympatho‐vagal balance contributes to the prolongation of myocardial repolarization.

Methods: Ten patients with ischemic heart disease (IHD), thirty patients with diabetes mellitus, and ten control subjects (CONT) volunteered for this study. The patients with diabetes mellitus were further divided into three subgroups according to the severity of neuropathy: patients without any neuropathy (NO), with peripheral neuropathy (N1) and with autonomic neuropathy (N2). ECG activation time (AT), activation recovery interval (ARI), and recovery time (RT) was measured and ECG R‐R spectral analysis was performed.

Result: There were significant decreases (P < 0.01) in RTc in N1, N2, and IHD as compared with CONT and NO. In addition, HI of R‐R interval power spectrum were significantly decreased (P < 0.01) in N1, N2, and IHD than those in CONT and NO.

Conclusion: We have successfully developed and adapted a new computer system for simultaneous ECG RT measurements and ECG R‐R power spectral analysis, a putative index of autonomic dysfunction and risk for sudden cardiac death, to study patients with ischemic heart disease and with varying degrees of diabetic autonomic neuropathy. Those with little HI power, which reflects more severe diabetic neuropathy and a high risk of sudden cardiac death, had significantly longer RTc, which is consistent with sympatho‐vagal imbalance toward parasympathetic denervation.
Wavelet Analysis of Signal‐Averaged Electrocardiograms
Authors: Hnatkova Katerina , Malik Marek , Kulakowski Piotr , Camm A. John
Published: October 2006

Background:Wavelet representation is able to detect low amplitude patterns even if hidden within signals of much higher amplitudes.

Method:A software system has been developed that implements wavelet representation of signal‐averaged electrocardiograms (SAECG). In this system, wavelet analysis leads to 4 numerical parameters that characterize the content of low amplitude perturbations found within the high gain QRS complex. In three substudies, these numerical parameters were compared with the standard time‐domain indices of SAECG.

Populations:Normal limits were identified from recordings of 104 normal healthy volunteers (54 males, mean age 50 ± 17 years). Short‐term reproducibility of the numerical indices and of abnormal findings was evaluated in a population of 85 subjects (16 healthy volunteers, 22 patients with documented ventricular tachycardia [VT] without structural heart disease, 30 patients with documented sustained postinfarction VT, and 17 survivors of acute myocardial infarction) who were each recorded three times with 5‐minute periods separating individual recordings. The power of wavelet and time‐domain analyses in distinguishing patients with and without sustained VT after myocardial infarction was assessed using recordings of 53 patients with postinfarction VT and of 53 age, sex, and infarct site matched patients without a history of arrhythmic complications after infarction.

Results:The studies have shown that (a) the indices of wavelet analysis are more reproducible than the time‐domain indices, (b) the distinction between patients with and without VT after myocardial infarction is similarly powerful by wavelet and time‐domain analyses, and the association of the positive SAECG analysis with postinfarction VT is highly significant with both analyses (P = 3.94 × 10–14 for wavelet analysis and 2.55 × 10−9 for time‐domain analysis), the indices of wavelet analysis differ significantly between normals and patients with an uncomplicated history of myocardial infarction (P = 0.02–0.005), while time‐domain indices do not (all parameters NS), (d) in contrast to the time‐domain analysis, wavelet analysis was similarly powerful in identifying VT patients with anterior and inferior infarction (P = 1.4 × 10−9, n = 30, and P = 2.0 × 10−15, n = 23, respectively).

Conclusion:Wavelet analysis is a highly reproducible method for SAECG processing which (a) is as powerful as the time‐domain analysis for the identification of ischemic VT patients, (b) compared to the time‐domain analysis, is not dependent on infarct site, and is able to distinguish postmyocardial infarction patients without VT from healthy subjects. A.N.E. 2000,5(1):4–19
Comparison of Various Measures of Optimum Atrial Timing in Patients with Dual Chamber Pacemakers
Authors: Pai Sudha M. , Jacobson Alan K. , Pai Ramdas G.
Published: October 2006

Background:In patients with dual chamber pacemakers, the optimal AV delay is highly variable. This study examines the alternative measures of optimum atrial timing and the factors responsible for the marked variability in the optimal AV delay.

Methods and results:Twelve patients with dual chamber pacemakers were studied. The AV delay was varied from 25 to 250 ms in 25‐ms increments and at each stage, mitral, tricuspid, and aortic flows were recorded using the Doppler technique. The optimum AV delay varied from 75 to 175 ms (146 ± 37 ms). At optimum AV delay, both the E and A waves of the transmitral flow were partially fused, eliminating diastasis with a fusion velocity of 27 ± 14 cm/s. The stroke distance was lower when the E and A waves were not fused at shorter AVD, despite a longer diastolic filling period, or fully fused at a longer AVD, which also the shortened diastolic filling period. At optimum AV delay, the E/A velocity ratio was 0.74 ± 0.15, reflecting slight atrial predominance of LV filling. The optimum timing of atrial contraction was better defined in terms of its relation to LV ejection (175 ± 31 ms before LV ejection), and this had a smaller coefficient of variation than optimum AV delay. This interval, unlike the AV delay, was not affected by interatrial and interventricular conduction times.

Conclusions:In this older population of patients with dual chamber pacemakers without significant valvular heart disease, the effective LA contraction in relation to LV ejection is a better measure of atrial timing than the programmed AV delay which is affected by atrial and ventricular conduction times. A.N.E. 2000;5(1):68–72
Relationship Between Myocardial Beta‐Adrenergic Sensitivity and Heart Rate Variability
Authors: Cabrol Philippe , Galinier Michel , Pathak Atul , Fourcade Joelle , Soula Philippe , Tran Marie‐Antoinette , Boveda Serge , Montastruc Jean‐Louis , Fauvel Jean‐Marie , Senard Jean‐Michel
Published: October 2006

Background: In congestive heart failure, despite activation of the sympathetic nervous system, heart rate variability parameters reflecting sympathetic modulation on sinus node are decreased. Our goal was to assess the role of beta‐adrenergic sensitivity in the modulation of heart rate variability (HRV) in patients with valvular heart diseases.

Methods and results: Ten patients with aortic stenosis, 10 patients with heart failure, and 12 controls were included. Baroreflex sensitivity was calculated by the sequency method. Noradrenaline plasma levels were assayed by HPLC. HRV was studied using 24‐hour Holter monitoring. Cardiac beta‐adrenergic receptivity was assessed by the chronotropic response to dobutamine. Right auricular samples were obtained for determination of beta‐adrenergic receptor density by binding study with [125I]‐iodocynaopindolol, and beta 1 and beta 2 densities, measured by competition between 125ICP binding by isoprenaline. In multivariate analysis, the dose of dobutamine that increases basal heart rate for 25 beats/min (ED25) is correlated with a parameter of global HRV: SDNN (r = 0.6, P < 0.001) and with indexes reflecting rather sympathetic modulation of HRV: SDANN (r = 0.62, P < 0.001) or SD (r = 0.47, P < 0.0001). All these relations were independent from mean NN, spontaneous baroreflex sensitivity, and noradrenaline plasma levels. No significant correlation existed between dobutamine ED25 and HRV indexes reflecting parasympathic tone. No relationship existed between HRV and beta‐adrenergic receptor‐binding characteristics.

Conclusion: Cardiac beta‐adrenergic sensitivity explored by dobutamine ED25 is an important determinant of HRV independent from mean NN, spontaneous baroreflex sensitivity, and noradrenaline plasma levels.
Detection of Exercise‐Induced Myocardial Ischemia by Multichannel Magnetocardiography in Single Vessel Coronary Artery Disease
Authors: Hänninen Helena , Takala Panu , Mäkijärvi Markku , Montonen Juha , Korhonen Petri , Oikarinen Lasse , Nenonen Jukka , Katila Toivo , Toivonen Lauri
Published: October 2006

Background: Detection of myocardial ischemia was studied with multichannel exercise magneto‐cardiography (MCG). A surface gradient method was applied to analyze cardiac magnetic fields.

Methods: We studied 27 patients with single vessel coronary artery disease (CAD) and 17 healthy volunteers. The MCG was recorded over anterior chest during supine bicycle ergometry. The two‐dimensional direction of the maximum spatial magnetic field gradient was determined during the ST segment and at the T‐wave apex at different phases of stress test.

Results: The CAD patient group was separated from controls by the orientation of the magnetic field gradient during the ST segment at cessation of exercise (CAD 167 ± 68° vs controls 106 ± 49°; P < 0.005) and at 4 minutes postexercise, but not at rest. The‐CAD patient group was separated from controls also by the orientation of the magnetic field gradient at the T‐wave apex at 4 minutes postexercise (CAD 87 ± 60° vs controls 58 ± 18° P < 0.05), but not at rest. The change in the orientation of the field gradient at the T‐wave apex 4 minutes postexercise, compared to baseline, was greater in CAD patients (31 ± 43°) than in controls (9 ± 8° P < 0.05). This change was larger in the patient group with stenosis in the right than in the left coronary artery (P < 0.05).

Conclusions: Transient acute myocardial ischemia causes well‐recognizable changes in the magnetocardiogram at the ST segment and the T wave. The orientation of the maximum spatial gradient of the magnetic field can be used as a parameter to determine these changes.
Different Action of Beta‐blockers on Daytime and Nighttime Heart Rate Variability
Authors: Brembilla‐Perrot B. , Houriez P. , Claudon O. , Beurrier D. , Preiss J.P.
Published: October 2006

Background: Beta‐blockers in patients surviving acute myocardial infarction (AMI) and in those with dilated cardiomyopathy have proven to be of beneficial effect, particularly for the sudden cardiac death rate. They are also used to control various forms of arrhythmias because of the strong correlation between cardiac arrhythmias and adrenergic reaction. Heart rate variability (HRV) variables provide valuable information related to the autonornic nervous system function. The present prospective study was undertaken to investigate the effects of beta‐blockers on 24‐hour HRV.

Methods: We studied 60 patients, aged 39 to 76 years (mean 56 ± 15). Forty of the patients had survived a myocardial infarction 12 to 24 months previously (group I). Twenty patients did not have apparent cardiac heart disease (group II). Twenty‐four‐hour monitoring was performed at baseline and after 8 to 10 days of atenolol (100 mg/day, n = 35) or metoprolol (100 to 150 mg/day, n = 25) (BB). Measures of HRV in the time and frequency domains were calculated and printed for the the entire 24 hours and from 09:00 to 21:00 (daytime) and 23:00 to 6:00 (nighttime). The 24‐hour analysis of HRV shows an improvement over control values in indices of parasympathetic tone, but the results were statistically significant only for high frequency power (HF) in groups I (P < 0.01) and II (P < 0.05). A significant decrease of the coefficient of variance was noted in group II (P < 0.05). The analysis during the day and the night revealed a predominant action of beta‐blockers during the night with a high frequency increase in both groups from 64.5 ± 45 to 161 ± 111 ms2 in group I (P < 0.001) and from 99 ± 89 to 268 ± 348 ms2 in group II (P < 0.02). In group II, the daily high frequency power did not vary after beta‐blockers. The decrease of the coefficient of variance in group II disappeared in the daily and nightly analysis

Conclusions: Beta‐blockers enhance the HRV indexes reflecting the parasympathetic activity especially during the night in patients with and without ischemic heart disease. Although an indirect effect of beta‐blockers on respiration cannot be excluded, this effect could explain one of the beneficial effects of beta‐blockers on general survival in patients with and without myocardial infarction.
Circadian Modulation of Atrial Cycle Length in Human Chronic Permanent Atrial Fibrillation: A Noninvasive Assessment Using Long‐Term Surface ECG
Authors: Cosson Stéphane , Maison‐Blanche Pierre , Olsson S. Bertil , Leenhardt Antoine , Badilini Fabio , Coumel Philippe
Published: October 2006

Objectives: Short‐term autonomic influences on the electrophysiological properties (EP) of the atrial myocardium are well known, but the role of long‐term sympathovagal influences on EP is less clear. This study aimed at finding if a circadian pattern could be identified in atrial EP, using the fibrillatory wave (F wave) of surface ECG recordings as a surrogate of atrial refractoriness in patients with chronic permanent atrial fibrillation (AFib).

Methods: 24‐hour two‐channel Holter ECG were obtained in 20 consecutive patients (mean age 70 ± 8 years) with nonvalvular, chronic and permanent AFib, free of antiarrhythmic agents except digoxin. Digitized ECG were analyzed by a custom software. After QRST substraction of detected complexes, the residual F waves (5‐min duration) were computed by a Fourier algorithm. The dominant frequency peak of the power spectrum obtained has been shown to correspond to the dominant atrial cycle length (DACL). 24‐hour recordings were analyzed separately during the day (8 active and awake consecutive hours) and at night (4 resting and asleep consecutive hours), and DACL was calculated hourly for each diurnal and nocturnal periods.

Results: Spectra could be reliably studied in 17 patients (85%). The DACL showed a significant circadian pattern with a mean 3.3% increase, from 151 ms in the diurnal period to 156 ms at night (P < 0.001). A significant positive relation was found between circadian day‐night changes of DACL and the baseline DACL value (P < 0.05). Mean ventricular heart rate decreased from 87 beats/min during the diurnal period to 71 beats/min at night (P < 0.001).

Conclusion: Spectral analysis of the F wave can be successfully achieved from long‐term Holter recordings. In chronic permanent AFib, the DACL still shows a circadian rhythmicity with an increase from day to night. In addition to atrial refractoriness, the amplitude of DACL circadian modulation could represent a new index of atrial electrical remodeling.
Circadian Behavior of P‐Wave Duration, P‐Wave Area, and PR Interval in Healthy Subjects
Authors: Dilaveris Polychronis E. , Färbom Patrik , Batchvarov Velislav , Ghuran Azad , Malik Marek
Published: October 2006

Background: The prolongation of P‐wave duration has long been shown to indicate the presence of high risk for atrial fibrillation. The circadian variation of P‐wave characteristics and their dynamic adaptation to heart rate changes was not tested before.

Methods: To evaluate the diurnal pattern of P‐wave duration, P area, and PR interval and of their linearly fitted relation with RR interval, 50 healthy volunteers (25 men, mean age 34 ± 10 years) underwent 24‐hour ambulatory electrocardiographic (ECG) recording with digital 12‐lead Holter recorders. The median P‐wave duration, P area, and PR interval were calculated from the average 12‐lead ECG constructed from each 10‐second ECC recording. Single harmonic regression analysis was performed to reveal the presence of circadian variation in the aforementioned ECG parameters.

Results: The P area (P < 0.0001, R2= 0.78), the PR interval (P < 0.0001, R2= 0.92), the P area / RR slope (P < 0.0001, R2= 0.55), and the PR/RR slope (P < 0.0001, R2= 0.42) showed a highly significant circadian variation while the periodic nature of P‐wave duration (P = 0.016, R2= 0.32) and of the P duration / RR slope (P = 0.011, R2= 0.18) was only indicated by harmonic regression analysis.

Conclusions: P‐wave duration, P area, and PR interval show a significant circadian variation in healthy subjects. The relations between P area/RR,PR/ RR, and P duration/RR also demonstrate a significant diurnal pattern.

A.N.E. 2001;6(2):92–97
The Diagnostic Value of 12‐Lead Electrocardiogram in Predicting Infarct‐Related Artery and Right Ventricular Involvement in Acute Inferior Myocardial Infarction
Authors: Kabakci Giray , Yildirir Aylin , Yildiran Levant , Batur Mustafa Kemal , Cagrikul Rasit , Onalan Orhan , Tokgozoglu Lale , Oto Ali , Ozmen Ferhan , Kes Sirri
Published: October 2006

Background: The aim of the present study was to investigate the predictive value of presentation and 24‐hour electrocardiograms in defining the infarct‐related artery (IRA), its lesion segment, and the right ventricular involvement in acute inferior myocardial infarction (Ml).

Methods: One hundred forty‐nine patients with acute inferior MI were included. Infarct‐related artery, its lesion segment, and the validity of new ECG criteria for the diagnosis of right ventricular Ml (RVMI) were investigated by means of criteria obtained from admission and 24‐hour ECGs.

Results: The presence of ST‐segment elevation in lead III > lead II criterion (Criterion 1) and ST‐segment depression in lead I > lead aVL criterion (Criterion 2) from admission ECG defined the right coronary artery (RCA) as IRA with a sensitivity of 64% and a specificity of 100%. These two criteria also defined the proximal or mid lesions in RCA as culprit lesions (sensitivity of 99%, specificity of 96%). Absence of these two criteria indicated Cx as IRA with a sensitivity of 50% and a specificity of 97%. The depth of Q wave in lead III > lead II criterion (Criterion 3) had no value for discrimination of IRA, but the width of Q wave in lead III > lead II criterion (Criterion 4) supported the RCA to be IRA with a sensitivity of 60% and a specificity of 61% (Criteria 3 and 4 were obtained from 24‐hour ECGs). The finding of Criterion 1 plus Criterion 5 (ST elevation in V1 but no ST elevation in V2) on admission ECG had a sensitivity of 63% and a specificity of 99% in the diagnosis of RVMI.

Conclusion: We concluded that 12‐lead ECG is a cheap, easy, and readily obtainable diagnostic approach in discrimination of IRA and its culprit lesion segment. However, despite high specificity, due to moderate degree sensitivity, its value for the diagnosis of RVMI is questionable. A.N.E. 2001; 6(3):229–235
AV Nodal Pathways in the R‐R Interval Histogram of the 24‐Hour Monitoring ECG in Patients with Atrial Fibrillation
Authors: Weismüller Peter , Kratz Caroline , Brandts Bodo , Kattenbeck Klaus , Trappe Hans‐Joachim , Ranke Carsten
Published: October 2006

Background: Patients with more than one AV nodal pathway show two and more peaks in the histogram of the R‐R intervals of the Holter monitoring ECG during atrial fibrillation. It was the purpose of the present study to determine the number of patients showing more than one AV nodal pathway in a larger patient group with permanent atrial fibrillation by analyzing the Holter monitoring ECG.

Methods: 250 patients with permanent atrial fibrillation during Holter monitoring ECG were studied; 203 patients had structural heart disease. The number of peaks in the R‐R interval histogram of each patient was determined. The distribution of the number of peaks in the R‐R interval histogram in different patient groups was analyzed.

Results: 153 patients (61 %) had one peak, 80 patients (32%) two peaks, 13 patients (5%) three peaks, and four patients (2%) four peaks, reflecting the number of different AV nodal pathways. In the different patient groups, in the patients with or without structural heart disease, with coronary heart disease, with a history of syncope, and in patients with a mean heart rate of more than 100/min, there was no significant difference in the distribution of the number of peaks in the R‐R interval histogram.

Conclusions: In more than one third of all patients with permanent atrial fibrillation there are two, three, or four AV nodal pathways. It is suggested that this number of different AV nodal pathways found in the studied group can be applied to all humans. 38.8% of all patients with permanent atrial fibrillation have more than one AV nodal pathway; 6.4% of all patients with atrial fibrillation would benefit from an ablation of AV nodal pathways with shorter refractory periods for reduction of the heart rate. A.N.E. 2001;6(4):285–289
Weighing the QT Intervals with the Slope or the Amplitude of the T Wave
Authors: Lund Kaspar , Nygaard Hans , Kirstein Pedersen Anders
Published: October 2006

Objective: The reproducibility of QT interval measurements is low, even for the mean QT interval based on the standard ECG. In this study we analyzed whether the reproducibility of the mean weighed QT interval was better than the simple mean QT interval. The weighing was based on the amplitude of the T wave or the slope of the steepest tangent on the terminal part of the T wave.

Material and methods: 12‐lead ECGs of 130 postmyocardial infarction patients were obtained. The QT intervals were measured by the tangent‐method on two occasions by the same observer Mismatch QT intervals were defined as QT intervals that were measured at only one occasion. Sixteen ECGs were rejected. The data were split into 34 and 80 ECGs for optimization and validation of the weighing, respectively. The weighed QT dispersion was calculated as the weighed mean of the three longest minus the weighed mean of the three shortest QT intervals.

Results: Weighing with the slope increased the reproducibility by 41% (P = 3 10‐6), but weighing with the amplitude reduced it by 20% (P = 0.02). However, if measurements with errors above 75 ms were rejected, weighing with the slope or the amplitude increased the reproducibility with 26% and 20% (P = 0.02), respectively. Weighing did not change the reproducibility of the weighed QT dispersion.

Conclusion: Weighing with the slope improved the reproducibility of the mean weighed QT interval. However, if measurements with errors above 75 ms were rejected, weighing with the amplitude also increased the reproducibility. Weighing did not change the reproducibility of the weighed QT dispersion. Weighing is particularly efficient at reducing the negative impact of mismatch QT intervals on the reproducibility. A.N.E. 2002;7(1):4–9
Effects of Menstrual Cycle on Cardiac Autonomic Innervation As Assessed By Heart Rate Variability
Authors: Yildirir Aylin , Kabakci Giray , Akgul Ebru , Tokgozoglu Lale , Oto Ali
Published: October 2006

Objective: The aim of the study was to investigate the effects of menstrual cycle on cardiac autonomic function parameters in young healthy women by means of heart rate variability (HRV).

Methods: Forty‐three nonobese regularly cycling women (age 29 ± 6, range 20–38) were enrolled. Recordings for HRV analysis were obtained during the two phases of the menstrual cycle when the estrogen and progesterone levels peaked (follicular phase 11 ± 1 days and luteal phase 21 ± 1 days from the start of bleeding). Power spectral analysis of HRV was performed to calculate the low frequency peak (LF, 0.04–0.15 Hz), high frequency peak (HF, 0.15–0.40 Hz), LF in normalized unit (LF nU), HF in normalized unit (HF nU), and LF/HF ratio during the two phases of menstrual cycle.

Results: The heart rates, LF and HF, were similar in both phases (P > 0.05). A significant increase was noted in the LF NU in the luteal phase compared to follicular phase of the menstrual cycle (P = 0.014), whereas a tendency for increased HF NU was observed in the follicular phase (P = 0.053). Furthermore, LF/HF ratio was significantly higher in the luteal phase compared to follicular phase (2.1 ± 1.5 vs 1.6 ± 0.9, P = 0.002), suggesting increased sympathetic activity in the luteal phase.

Conclusion: We concluded that regulation of autonomic tone is modified during menstrual cycle. The alteration in the balance of ovarian hormones might be responsible for these changes in the cardiac autonomic innervation. A.N.E. 2002;7(1):60–63
Randomized Study of Early Intravenous Esmolol Versus Oral Beta‐Blockers in Preventing Post‐CABG Atrial Fibrillation in High Risk Patients Identified by Signal‐Averaged ECG: Results of a Pilot Study
Authors: Balcetyte‐Harris Nomeda , Tamis Jacqueline E. , Homel Peter , Menchavez Edith , Steinberg Jonathan S.
Published: October 2006

Background: Patients with prolonged signal‐averaged ECG have four times higher risk for development of atrial fibrillation (AF) after coronary artery bypass surgery (CABG). Incidence of AF is reduced, but not eliminated by prophylaxis with beta‐blockers. The limitations of prophylaxis with oral beta‐blockers may be related to the delayed effect of oral therapy. We performed a pilot study of the efficacy of early intravenous esmolol and an oral beta‐blocker regimen for prevention of postoperative AF.

Methods: Fifty patients referred for CABG and considered to be at high risk for postoperative AF on the basis of prolonged signal‐averaged ECG P wave duration > 140 ms were randomized to receive either a 24‐hour infusion of esmolol 6–18 hours after CABG, at an average dose 67 ± 7 μ/kg/min, followed by oral beta‐blockers versus oral beta‐blockers only beginning on postoperative day 1.

Results: Seven of 27 patients (26%) in the esmolol group and 6 of 23 patients (26%) in the oral beta‐blocker group developed postoperative AF, P = NS. The mean time of onset of AF (2.7 ± 0.5 vs 2.7 ± 0.3 postoperative day, P = NS) and the median duration of AF (10 [2192] vs 7 [1.16] hours, P = NS) were similar between the two groups. Eleven (41%) patients treated with esmolol developed adverse events (hypotension: 8, bradycardia requiring temporary pacing: 2, left ventricular failure:1 patient) as compared to only one patient (4%) in the beta‐blocker group who developed hypotension, P = 0.006.

Conclusions: This randomized controlled pilot study suggests that intravenous esmolol is less well tolerated and offers no advantages to standard beta‐blocker in preventing AF after CABG.

A.N.E. 2002;7(2):86–91
What Percent Luminal Stenosis Should Be Used to Define Angiographic Coronary Artery Disease for Noninvasive Test Evaluation?
Authors: Lipinski Michael , Do Dat , Morise Anthony , Froelicher Victor
Published: October 2006

Background: There has been controversy over what is the best angiographic luminal dimension criterion associated with ischemia for evaluating diagnostic tests. If one assumes that ST‐segment depression or scores are indicators of ischemia, then whatever angiographic criteria best discriminates those with ischemic and nonischemic responses would be the best angiographic marker for ischemia. To study this, we calculated the area under the ROC curves for ST depression and scores at different angiographic cut‐points in order to determine the best angiographic cut‐point for defining ischemia‐producing coronary disease.

Methods: Twelve hundred and seventy‐six consecutive males without prior Ml with a mean age of 59 ± 11 years who had undergone exercise testing and coronary angiography were analyzed in this study. We calculated the number of patients of this population that would be considered to have coronary artery disease at different cut‐points for angiographic luminal stenosis. For example, 59% of the patients had significant CAD when disease was defined as 50% or greater coronary lumen stenosis of any coronary vessel while 49% of the patients had significant CAD when disease was defined as 70% or greater coronary lumen stenosis. Cut‐points were considered between 40 to 100% coronary lumen stenosis. ROC analysis was then performed comparing ST depression and treadmill scores at each of these cut‐points.

Results: The cut‐point for coronary lumen stenosis that returned the highest AUC for ST depression and scores was between 70 and 80% coronary luminal stenosis. However, the difference between the 50% and 75% luminal stenosis criteria was minimal.

Conclusion: It appears that the best cut‐point for defining significant angiographic disease when evaluating diagnostic tests of ischemia is 75% or greater coronary luminal stenosis. A.N.E. 2002;7(2):98–105
Effect of the Final Coronary Arterial Diameter After Coronary Angioplasty on Heart Rate Variability Responses
Authors: Kanadasi Mehmet , Kudaiberdieva Gulmira , Birand Ahmet
Published: October 2006

Background: Autonomic nervous system dysfunction and reduced heart rate variability (HRV) after percutaneous transluminal coronary angioplasty (PICA) were reported in patients with coronary artery disease. However, factors related to reduced HRV are not clearly demonstrated. The aim of the present study was to assess the relationship between HRV indices and the final coronary arterial luminal diameter after PICA.

Methods: Twenty‐seven patients (23 male, 4 female, mean age: 52.5 ± 7.1 years) with single vessel disease were included in the study. PTCA was performed in all patients. Low‐frequency power (LFP), high‐frequency power (HFP), and total power (TP) were calculated by using frequency‐domain analysis of HRV. All examinations were performed 24 hours before, and 24 hours, 10 days, and 30 days after PTCA. The patients were divided into groups according to the PTCA restenosis risk score, the degree of dilatation, and revascularization after coronary angioplasty.

Results: The groups were comparable for age, gender, and coronary artery risk factors. HRV was found to be reduced in 76% of patients. Reduction in HRV after PTCA was significantly related to the PTCA risk score and the degree of revascularization (r = 0.48, P < 0.01 and r = 0.50, P < 0.008). Reduction in HRV was more significant in patients with previous myocardial infarction (P < 0.05). Recovery of HRV occurred on the tenth day after PTCA.

Conclusion: Transient and rapidly recovered, especially parasympathetically modulated HRV reduction occurred after PTCA in patients with single‐vessel disease. HRV reduction is associated with PTCA restenosis risk score and the degree of revascularization as invasive feature of angioplasty, hence it may be related to reperfusion. A.N.E. 2002;7(2):106–113
Apnea‐Related Heart Rate Variability and Its Clinical Utility in Congestive Heart Failure Outpatients
Authors: Tateishi Osamu , Shouda Toru , Honda Youichi , Sakai Tomohisa , Mochizuki Seibu , Machida Katsuhiko
Published: October 2006

Background: Cheyne‐Stokes breathing (CSB) is an abnormal cyclical pattern of respiratory fluctuations observed during sleep in congestive heart failure (CHF) of poor prognosis. We examined the clinical usefulness of CSB screening using the heart rate variability (HRV) data from the ambulatory electrocardiogram.

Methods: We monitored ambulatory electrocardiograms and respiration simultaneously in 86 heart disease patients of both sexes, aged 57 ± 1 years. HRV was analyzed by the maximum entropy method during the sleeping period (11 PM—S AM). The 43 CHF patients underwent a 1‐year follow‐up study.

Results: In the power spectra of the HRV, peaks were observed within the CSB band (0.005 to 0.03 Hz). Statistically significant differences in HRV were observed between CSB patients and CSB‐free patients in very low frequency (VLF) (P = 0.04), VLF/total frequency (TF) (P = 0.02), CSB (P = 0.01), CSB/TF (P = 0.003), and CSB/VLF (P < 0.0001). Cardiac events occurred in 23% of patients, including cardiac death in two, and rehospitalization for aggravated CHF in eight. In a multivariate Cox regression analysis in which age, sex, ejection fraction, NYHA functional class, beta blocker use, and basic heart disease were included, absence of ACE inhibitor use (RR 5.5, 95% Cl 1.0–31) and CSB/VLF ≧ 80% (RR 4.2, 95% Cl 1.1–17) remained significant predictors of cardiac events.

Conclusions: HRV can act as an indicator of the presence of CSB in CHF patients, and could therefore be used, under outpatient conditions, to identify a CHF patients with a poor prognosis. A.N.E. 2002;7(2):127–132
Effects of Carvedilol on Heart Rate Dynamics in Patients with Congestive Heart Failure
Authors: Ridha Mustafa , Makikallio Timo H. , Lopera Gustavo , Pastor Juan , de Marchena Eduardo , Chakko Simon , Huikuri Heikki V. , Castellanos Agustin , Myerburg Robert J.
Published: October 2006

Background: Patients with congestive heart failure (CHF) have alterations in the traditional and nonlinear indices of heart rate (HR) dynamics, which have been associated with an increased risk of mortality. This study was designed to test the effects of carvedilol, a nonselective beta‐blocker with alpha‐1 blocking properties, on HR dynamics in patients with CHF.

Methods: We studied 15 patients with CHF secondary to ischemic or idiopathic cardiomyopathy who met the following inclusion criteria: NYHA functional class II‐III, optimal conventional medical therapy, normal sinus rhythm, left ventricular ejection fraction (LVEF) of < 40%, and resting systolic blood pressure greater than 100 mmHg. The 6‐minute corridor walk test, estimation of LVEF, and 24‐hour Holter recording were performed at baseline and after 12 weeks of therapy with carvedilol. Traditional time and frequency domain measures and short‐term fractal scaling exponent of HR dynamics were analyzed.

Results: After 12 weeks of therapy with carvedilol, the mean LVEF improved significantly (from 0.27 ± 0.08 to 0.38 ± 0.08, P < 0.001). The average HR decreased significantly (from 86 ± 11 to 70 ± 8 beats/min, P < 0.001). The mean distance traveled in the 6‐minute walk test increased significantly (from 177 ± 44 to 273 ± 55 m, P < 0.01). The frequency‐domain indices (HF and LF), the time domain indices (rMSSD and PNN5), and the short‐term fractal scaling exponent increased significantly. The scaling exponent increased particularly among the patients with the lowest initial values (< 1.0), and the change in the fractal scaling exponent correlated with the change in ejection fraction (r = 0.63, P < 0.01).

Conclusion: Carvedilol improves time and frequency domain indices of HR variability and corrects the altered scaling properties of HR dynamics in patients with CHF. It also improves LVEF and functional capacity. These specific changes in HR behavior caused by carvedilol treatment may reflect the normalization of impaired cardiovascular neural regulation of patients with CHF. A.N.E. 2002;7(2):133–138
Factors Associated with the Development of Atrial Fibrillation in COPD Patients: The Role of P‐Wave Dispersion
Authors: Tükek Tufan , Yildiz Pinar , Akkaya Vakur , Akif Karan Mehmet , Atilgan Dursun , Yilmaz Veysel , Korkut Ferruh
Published: October 2006

Background: Supraventricular tachyarrhythmia is a common problem in chronic obstructive pulmonary disease (COPD) patients. The purpose of this study is to analyze the factors associated with paroxysmal atrial fibrillation (AF) in COPD patients.

Methods: Forty COPD patients (38 male, 2 female, mean age 60 ± 9 years) and 33 healthy controls (29 male, 4 female, mean age: 58 ± 10 years) were included in this study. Echocardiography, 24‐hour ambulatory and 12‐lead ECG, pulmonary function tests, arterial blood gases, and serum electrolytes were measured. On ECG, maximum (Pmax) and minimum (Pmin) duration of P wave and its difference, P‐wave dispersion (PWd), were measured.

Results: On echocardiography, diastolic dysfunction was found in 14 of the 40 (35%) COPD patients. Heart rate variability analysis revealed that COPD patients had decreased SDANN, SDNN, SDNNIDX in time‐domain, and decreased LF in frequency domain parameters. Fourteen of the 40 COPD patients (35%) had AF. Patients with AF were older (57 ± 10 vs 64 ± 5 years, P = 0.03) and had lower SDANN, SDNN, and LF/HF ratio as compared to patients without AF in univariate analysis. All P‐wave intervals (Pmax Pmin and PWd) were increased in COPD patients compared to controls. P‐wave dispersion was significantly increased in COPD patients with AF, as compared to patients without AF (57 ± 11 vs 44 ± 7 ms, P = 0.001). In logistic regression analysis PWd was found to be the only factor associated with the development of AF (P = 0.04).

Conclusions: The presence of AF was significantly related to the prolongation of PWd, but not with pulmonary function, arterial blood gasses, and left and right atrial function. A.N.E. 2002;7(3):222–227
Heart Rate Variability After Coronary Artery Bypass Graft Surgery: A Prospective 3‐Year Follow‐Up Study
Authors: Demirel Şeref , Akkaya Vakur , Oflaz Huseyin , Tükek Tufan , Erk Osman
Published: October 2006

Background: Autonomic heart rate control is impaired after CABG. The aim of this study was to establish the temporal pattern of change in the decrease of HRV observed after CABG.

Methods and Results: Twelve patients with coronary artery disease were assessed with 24‐hour Holter recordings 2 days before CABG and 1 week, 3 months, 6 months, 1 year, and 3 years after CABG. All the time‐domain and frequency‐domain HRV parameters decreased precipitately after CABG and were mostly recovered 3 months after CABG except mean NN, rMSSD, and pNN50. The ratio of LF to HF showed a slight decrease after surgery, recovered to preoperative values after 3 months, surpassed, and continued to increase 6 months after surgery. At 3 years of follow‐up the recovery was complete. The rate of change of time‐domain and frequency‐domain parameters were calculated and their correlation with aortic cross‐clamping time, number of vessels bypassed, the amount of cardioplegic used were sought and no statistically significant correlation was found.

Conclusion: The recovery of HRV regardless to the preoperative state of the patients and their postoperative course implies that the early drop of HRV after CABG was related to the acute effects of surgery. Late complete recovery of HRV may be due to resolution of ischemia or use of angiotensin‐converting enzyme inhibitor. A.N.E. 2002;7(3):247–250
Microwave Dielectric Properties of Rare‐Earth Ortho‐Niobates with Ferroelasticity
Authors: Kim Dong‐Wan , Kwon Do‐Kyun , Yoon Sung Hun , Hong Kug Sun
Published: October 2006

In the search for more temperature‐stable materials, herein, we report on the microwave dielectric properties and trends of the rare‐earth niobate series (RENbO4), with the main emphasis being placed on LaNbO4. LaNbO4 has excellent microwave dielectric properties, especially an anomalous small positive temperature coefficient of resonant frequency of 9 ppm/°C. We present the phase transformation and ferroelastic domain configuration of RENbO4 studied using in situ X‐ray diffraction and high‐resolution transmission electron microscopy. The structural distortion caused by the phase transformation is a dominant factor in the relative dielectric constant and temperature coefficient of the resonant frequency in RENbO4.
One‐Step Fabrication of ZnWO4 Hollow Spheres by Nanoparticle Aggregation and Ripening in Alcohol Solution
Authors: Huang Jianhua , Gao Lian
Published: October 2006

A one‐step method has been developed to synthesize ZnWO4 spheres with a hollow‐core diameter of 450 nm and an outer spherical diameter of 1.2 μm. Experimental investigation reveals that the ZnWO4 spheres are formed through nanoparticle aggregation and ripening. Furthermore, introduction of appropriate water quantity to the reaction system is a key to obtain hollow‐core ZnWO4. The as‐obtained ZnWO4 hollow spheres exhibit a blue emission in the range of 350–550 nm, centered around 460 nm when excited at 254 nm.
Sintering Kinetics at Isothermal Shrinkage: Effect of Specific Surface Area on the Initial Sintering Stage of Fine Zirconia Powder
Authors: Matsui Koji , Matsumoto Akira , Uehara Masato , Enomoto Naoya , Hojo Junichi
Published: October 2006

The isothermal shrinkage behaviors of fine zirconia powders (containing 2.8–2.9 mol% Y2O3) with specific surface areas of about 6 and 16 m2/g were investigated to clarify the effect of specific surface area on the initial sintering stage. The shrinkage of powder compact was measured under constant temperatures in the range of 1000°–1100°C. The increase in specific surface area enhanced the densification rate with increasing temperature. The values of activation energy (Q) and frequency‐factor term (β0) of diffusion at initial sintering were estimated by applying the sintering‐rate equation to the isothermal shrinkage data. The Q of diffusion changes little but the β0 increases with the increase in specific surface area. It is therefore concluded that the increase in the specific surface area of fine zirconia powder enhances the shrinkage rate because of an increase in the β0 at the initial stage of sintering.
Analysis of polymorphism, structure and function of exon 2 of ovine melatonin receptor 1b gene: a clue as to why it lacks expression in sheep
Authors: Xiao Chao‐Ting , Chu Ming‐Xing , Fu Yan , Fang Li , Ye Su‐Cheng
Published: October 2006

Abstract:  To analyze the structure and function of the melatonin 1b receptor (MT2) in sheep, single nucleotide polymorphisms were detected in exon 2 of sheep MT2 gene using genomic DNA from five sheep breeds by five primers. Polymorphisms were found, and 33 nucleotide mutations were revealed by comparing the mutant types with the wild types. Among them, 14 give rise to deduced amino acid changes. However, none is likely to be associated with nonseasonal or seasonal estrus in sheep breeds tested. Sequence of exon 2 of MT2 of Small Tail Han sheep shows much closer phylogenetic relationship with predicted bovine and porcine MT2 than with human and mouse. The deduced amino acid sequence shows higher identity with the MT2 of cattle (95%) and pig (79%) than with human (76%) and mouse (71%). A rather high identity (61–63%) with the MT1 of sheep, human and mouse was also found. Compared with the other known MT2, 35 unique altered amino acids were revealed. Albeit it also contains a NAXXY motif in transmembrane 7, both a DRY motif and a CYVCR motif were detected just downstream from its third transmembrane domain rather than NRY and CYICH found in other melatonin receptor groups. We presumed that it is possible that the structural changes make its binding function to the ligands attenuated or disrupted, and other genes (most probably MT1) were substituted in the progress of evolution, which ultimately resulted in no detectable expression in current breeds of sheep.
Melatonin promotes adventitious‐ and lateral root regeneration in etiolated hypocotyls of Lupinus albus L.
Authors: Arnao Marino B. , Hernández‐Ruiz Josefa
Published: October 2006

Abstract:  Melatonin is a well‐known animal substance, which has recently been detected in plant tissues. However, there are only a few studies concerning its possible physiological role in plants. In this paper, we investigate the possible effect of melatonin on the regeneration of lateral and adventious roots in etiolated hypocotyls of Lupinus albus L. compared with the effect of indole‐3‐acetic acid. We performed this study by measuring both molecules in roots. Six‐day‐old derooted lupin hypocotyls immersed in several melatonin or indole‐3‐acetic acid concentrations were used to induce roots. A macro‐ and microscopic study of the histological origin of the adventitious and lateral roots was made, while melatonin and indole‐3‐acetic acid in the roots were quantified using liquid chromatography with fluorescence detection. The data show that both melatonin and indole‐3‐acetic acid induced the appearance of root primordia from pericicle cells, modifying the pattern of distribution of adventitious or lateral roots, the time‐course, the number and length of adventitious roots, and the number of lateral roots. Melatonin and indole‐3‐acetic acid were detected and quantified in lupin primary roots, where both molecules were present in similar concentrations. The physiological effect of exogenous melatonin as root promoter was demonstrated, its action being similar to that of indole‐3‐acetic acid.
Protein kinase Cθ activity is involved in the 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin‐induced signal transduction pathway leading to apoptosis in L‐MAT, a human lymphoblastic T‐cell line
Authors: Ahmed Sohel , Shibazaki Masahiko , Takeuchi Takashi , Kikuchi Hideaki
Published: October 2006

The aromatic hydrocarbon receptor (AhR)‐dependent pathway involved in 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD)‐induced immunotoxicity has been studied extensively, but the AhR‐independent molecular mechanism has not. In previous studies we found that the AhR is not expressed in L‐MAT, a human lymphoblastic T‐cell line. In this report, we provide the following evidence that the protein kinase C (PKC)θ activity is functionally involved in the AhR‐independent signal transduction mechanism that participates in the TCDD‐induced L‐MAT cell apoptosis. First, only rottlerin, a novel PKC (nPKC)‐selective inhibitor, blocked the apoptosis completely, in a dose‐dependent manner. Second, PKCθ was the major nPKC isoform (compared to PKCδ) expressed in the L‐MAT cell line. Third, a cell‐permeable myristoylated PKCθ pseudosubstrate peptide inhibitor also blocked the apoptosis completely, in a dose‐dependent manner. Fourth, both rottlerin and myristoylated PKCθ pseudosubstrate peptide inhibitor completely inhibited PKCθ kinase activity in vitro at doses that effectively blocked TCDD‐induced L‐MAT cell apoptosis. TCDD treatment induced a time‐dependent activation of nPKC kinase activity in L‐MAT cells, and moreover, TCDD induced a translocation of PKCθ from the cytosolic fraction to the particulate fraction in L‐MAT cells. Finally, transient over‐expression of a dominant negative PKCθ (a kinase‐dead mutant, K/R 409) in L‐MAT cells conferred significant protection against TCDD‐induced apoptosis.
In silico analysis of the adenylation domains of the freestanding enzymes belonging to the eucaryotic nonribosomal peptide synthetase‐like family
Authors: Di Vincenzo Leonardo , Grgurina Ingeborg , Pascarella Stefano
Published: October 2006

This work presents a computational analysis of the molecular characteristics shared by the adenylation domains from traditional nonribosomal peptide synthetases (NRPSs) and the group of the freestanding homologous enzymes: α‐aminoadipate semialdehyde dehydrogenase, α‐aminoadipate reductase and the protein Ebony. The results of systematic sequence comparisons allow us to conclude that a specificity‐conferring code, similar to that described for the NRPSs, can be recognized in such enzymes. The structural and functional roles of the residues involved in the substrate selection and binding are proposed through the analysis of the predicted interactions of the model active sites and their respective substrates. The indications deriving from this study can be useful for the programming of experiments aimed at a better characterization and at the engineering of this emerging group of single NRPS modules that are responsible for amino acid selection, activation and modification in the absence of other NRPS assembly line components.