bluuebunny/crossref_metadata_2025_split huggingface dataset:
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 analysisConclusions: 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