bluuebunny/crossref_metadata_2025_split huggingface dataset:
Baroreflex Sensitivity
Authors: La Maria Teresa Rovere  
Published: October 2006

BackgroundArterial baroreceptors play a central role in governing autonomic outflow to the heart and are involved in the electrophysiological mechanisms by which sympathetic activation may initiate a ventricular tachyarrhythmia and vagal activation may have antifibrillatory effects. Stimulation of arterial baroreceptors results in sympathoinhibition and efferent vagal activation. Cardiovascular disease may alter baroreceptor function leading to inappropriate or excessive autonomic activity in response to blood pressure changes.MethodsEvidence obtained in an experimental preparation in chronically infarcted dogs opened the way to the understanding of the importance of the analysis of baroreceptor control of heart rate in risk stratification. Among several methodologies, the measurement of the reflex R‐R interval lengthening following a blood pressure rise induced by bolus injections of phenylephrine has been shown to provide clinically relevant information as a measure of the capability to augment vagal activity.ResultsFollowing pilot studies conducted by different groups of investigators, the Autonomic Tone and Reflexes After Myocardial Infarction (ATRAMI) trial in a series of 1284 myocardial infarction patients has demonstrated that the prognostic value of baroreflex sensitivity is largely independent from the established clinical predictors such as left ventricular ejection fraction and ventricular arrhythmias.ConclusionsIn these patients, the value of the information obtained by the combination between left ventricular function and baroreflex sensitivity suggests that this analysis should be included in the risk stratification strategy for identification of patients who may need an implantable automatic defibrillator for primary prevention of sudden cardiac death. The analysis of baroreceptor reflexes is of prognostic value also in patients with chronic heart failure.
Relationships of Chronic Hyperinsulinemia, Heart Rate Variability, and Circadian Variation of Blood Pressure in Obese Hypertensive Subjects
Authors: Galinier Michel , Fourcade Joëlle , Boveda Serge , Ley Nicolas , Solera Sophie , Solera Marie Laure , Pîrvu Octavian , Massabuau Pierre , Cabrol Philippe , Fauvel Jean Marie , Valdiguie Pierre , Bounhoure Jean Paul 
Published: October 2006

Background:During insulin resistance, sympathetic nerve activity is increased. However insulin resistance is a common feature of obesity and essential hypertension, it is unclear if chronic hyperinsulinemia per se contributes to sympathetic overactivation. The purpose of our study was to explore the relationship between hyperinsulinemia and heart rate variability (HRV), a noninvasive tool to assess autonomic function, in obese and hypertensive subjects. Methods:24‐hour Holter ECG for HRV time and frequency domain analysis was performed in 77 patients: mean age 53 ± 10 years; 52 men and 25 women; free of diabetes; without beta‐blockers. The patient were divided into four groups according to three parameters, body mass index (BMI > 27 kg/m2 in the men and > 25 kg/m2 in the women defined obesity), arterial pressure, and insulinemia (fasting insulinemia > 25 mUI/L defined hyperinsulinemia). Twenty‐seven patients were obese, hypertensive, with hyperinsulinemia; 28 patients obese, hypertensive, without hyperinsulinemia; 12 patients nonobese, hypertensive, without hyperinsulinemia; 10 patients obese, normotensive, without hyperinsulinemia. Results:In comparison with the three other groups, patients with hyperinsulinemia showed a significant decrease (P < 0.05) of SDNN and the power of total spectrum (0.01–1 Hz) band, which are indexes of global HRV, and a significant decrease (P < 0.005) of SD and the normalized power of the low frequency (0.04–0.15 Hz) band, both indexes reflecting sympathetic modulation of HRV. In contrast, no significant difference was observed among the four groups for indexes of HRV reflecting parasympathetic tone. These relations were independent of mean R‐R. Fasting insulinemia was significantly (P < 0.0001) related with HRV in time domain (SDNN: r =−0.43; SD: r =‐0.49) and spectral domain (total spectrum: r =−0.49; low frequency: r =−0.52). Conclusion:Chronic hyperinsulinemia appears to be an important determinant of HRV, particularly for the indexes reflecting sympathetic influence, independent of obesity and hypertension. A.N.E. 1999;4(3):316–324
Noninvasive Electrocardiographic Imaging
Authors: Rudy Yoram , Burnes John E. 
Published: October 2006

Background:Cardiac arrhythmias continue to be a leading cause of death and disability. Despite this alarming fact, a noninvasive imaging modality for cardiac electrophysiology (EP) has not been developed. Standard electrocardiographic techniques attempt to infer electrophysiological processes in the heart from a limited number of recordings on the body surface. This traditional approach is limited in its ability to provide information on regional electrocardiac activity and to localize electrophysiological events in the heart (e.g., arrhythmogenic foci; regions of elevated dispersion of myocardial repolarization). This article reviews the development of a novel imaging modality (electrocardiographic imaging [ECGI]) for the reconstruction of cardiac electrical activity from potentials measured away from the heart (i.e., on the torso surface). The results presented demonstrate that ECGI can noninvasively reconstruct epicardial potentials, electrograms, and isochrones with good accuracy and resolution.Results:The locations of ectopic pacing sites are reconstructed within 10 mm of their actual positions. Dual epicardial pacing sites separated by 52 mm, 35 mm, and 17 mm can be resolved. The depth of intramural ectopic activity can be estimated and the direction of intramural activation spread can be determined from the reconstructed epicardial potential pattern and its evolution in time. Results from infarcted hearts demonstrate that ECGI can detect and reconstruct the abnormal electrophysiological substrate associated with the infarct. The figure‐of‐eight pattern of reentrant activation in the epicardial border zone during ventricular tachycardia is also reconstructed by ECGI noninvasively.Conclusions:These results demonstrate the potential of ECGI as a clinical noninvasive imaging modality for identifying patients at risk of cardiac arrhythmias and for guiding and evaluating antiarrhythmic interventions in such patients. A.N.E. 1999;4(3):340–359
Noninvasive Testing for Selection of Patients for Electrophysiological Study
Authors: Anderson Kelley P. , Shusterman Vladimir , Brode Susan , Gottipaty Venkateshwar , Schwartzman David , Weiss Raul 
Published: October 2006

Background:The implantable cardioverter defibrillator (ICD) has underscored the limitations of our methods of risk assessment. ICDs should be available to patients at high risk for arrhythmic death, but because of the potential for adverse effects and high cost it should be scrupulously avoided in patients whose lives will not be prolonged. Unfortunately, discrimination between these two groups of patients remains a challenge. Recent clinical trial results have not only shown that electrophysiological studies (EPS) in combination with other risk stratifiers identify patients with ischemic heart disease at high risk for arrhythmic death, but they have linked the efficacy of ICD therapy to the results of EPS. However, to perform EPS in all potential candidates for ICD therapy would be a time‐consuming and costly burden to medical services and would expose many patients to the risks and discomfort of an invasive procedure. Noninvasive identification of appropriate candidates is therefore essential to successful application of EPS. Methods:Nonsustained ventricular tachycardia (NSVT) and a reduced left ventricular ejection fraction (EF) was used to select patients for EPS in two important trials, but it is not certain that these are the optimal tests or that the optimal thresholds 1 episode of NSVT 3 beats; EF 0.35 or EF 0.40) were used. A number of studies have addressed the accuracy of clinical factors for predicting the results of EPS and a number of noninvasive tests have been proposed including the signal‐averaged electrocardiogram, heart rate variability, T‐wave alternans, and high spatial resolution (multilead) electrocardiography. In some contexts, combinations of factors provide significant improvements in accuracy. However, the populations studied were often highly selected, which makes comparisons between techniques or prediction of responses in the populations that would require screening difficult. Results from recently completed and ongoing clinical trials should provide important new information. A greater problem is that EPS has not been shown to consistently provide accurate discrimination of patients with nonischemic cardiac disorders. Conclusions:Effective widespread application of ICD therapy will require greater precision of patient selection. Noninvasive tests under investigation demonstrate considerable promise in selecting appropriate candidates for EPS. However, because the most precise methods of risk assessment are likely to be those most closely linked to the mechanisms of fatal arrhythmias, it is important that further development of noninvasive techniques incorporates advances in basic cardiac electrophysiology. A.N.E. 1999;4(4):434–442
Heart Rate Variability to Assess Changes in Cardiac Vagal Modulation Prior to the Onset of Paroxysmal Atrial Fibrillation in Patients With and Without Structural Heart Disease
Authors: Klingenheben Thomas , Grönefeld Gerian , Li Yi‐Gang , Hohnloser Stefan H. 
Published: October 2006

Background and Objectives: In patients with paroxysmal lone AF, clinical data indicate a predominance of vagal modulation preceding attacks of the arryhthmia. Systematic data derived from time‐domain analysis of HRV evaluating changes in autonomic modulation prior to AF onset are sparse, both in patients without and with evidence for structural heart disease. This study evaluated changes in autonomic modulation prior to the onset of AF in patients with and without structural heart disease.Methods and Results: In 26 consecutive patients with at least one episode of paroxysmal AF preceded by a period of sinus rhythm of at least 8 hours duration documented on Holter monitoring, the time‐domain parameters SDNN, rMSSD, and pNN5O were analyzed at different time points between 8 hours and 10 minutes prior to the onset of AF. Fourteen patients had AF associated with structural heart disease, whereas 12 patients had paroxysmal lone AF. Analysis of HRV changes before onset of AF revealed significant differences between the two patient groups: In patients without heart disease, pNN5O and rMSSD increased from 10 ± 3 to 15 ± 4% (P=0.003) and from 38 ± 7 to 53 ± 9 ms (P=0.035). No significant change in HRV was observed in patients with structural heart disease (pNN5O 5 ± 3 vs. 6 ± 2 % and rMSSD 25 ± 4 vs. 28 ± 6 ms).Conclusions: In patients with lone AF, there is a significant shift of autonomic modulation towards a vagal predominance prior to the onset of paroxysmal AF as compared to patients with structural heart disease. Analysis of HRV prior to attacks of AF is useful in determining these triggering mechanisms.
Time‐Frequency Analysis of Heart Rate Variability in Hypertension: Clinical and Echocardiographic Associations
Authors: Kudaiberdieva Gulmira Z. , Birand Ahmet , Saliu Sokol 
Published: October 2006

Background: Autonomic regulation of heart rate is impaired in hypertensive patients. The aim of this study is to elucidate the relation between HRV measures as assessed in time‐frequency and frequency domains and clinical and echocardiographic features of hypertension with and without left ventricular hypertrophy.Methods: Forty patients with hypertension were divided into two groups according to gender adjusted echocardiographic signs of left ventricular hypertrophy: group 1–20 patients with hypertension and normal LVMI; group 11–20 patients with hypertension and echocardiographic signs of left ventricular hypertrophy. The control group consists of 20 age‐matched healthy subjects. HRV analysis was accomplished using frequency‐domain analysis (fast Fourier transform) and time‐frequency analysis (smoothed pseudo‐Wigner distribution).Results: HRV components, very low frequency power (VLFP), low frequency power (LFP), high frequency power (HFP), and total power (TP) were attenuated (P > 0.05) in hypertensive patients with and without left ventricular hypertrophy. LFP/HFP and low frequency related power (LFRP) were markedly higher in group I patients than of group II and controls (P > 0.01, P > 0.0001, and P > 0.001, P > 0.05, respectively). While patients of group II had significantly lower values of VLFP, LFP, LFP/HFP ratio and LFRP as compared with group I patients (P > 0.04, P > 0.0001, P > 0.01, and P > 0.0001, respectively). The burst activity at 0.1 Hz was increased in group I patients while in group II patients it was attenuated. HRV indices associated significantly with cardiac output and systolic blood pressure in patients without signs of left ventricular hypertrophy. In patients with signs of left ventricular hypertrophy, HRV indices correlated with LVMI, related wall thickness, age, and body surface area.Conclusion: HRV responds differently in different stages of hypertension, with increase response of sinus node to sympathetic influences in hypertension without left ventricular hypertrophy and withdrawal of sympathetic and parasympathetic influences in presence of left ventricular hypertrophy.
P Wave Dispersion: A Valuable Electrocardiographic Marker for the Prediction of Paroxysmal Lone Atrial Fibrillation
Authors: Gialafos John E. , Dilaveris Polychronis E. , Gialafos Elias J. , Andrikopoulos George K. , Richter Dimitrios J. , Triposkiadis Filippos , Kyriakidis Michael K. 
Published: October 2006

Background: The prolongation of atrial conduction time and the inhomogeneous propagation of sinus impulses are well known electrophysiological characteristics in patients with paroxysmal atrial fibrillation.Methods: The aim of this study was to test the ability of a new ECG marker to discriminate between patients with a prior history of paroxysmal lone atrial fibrillation and healthy controls. Maximum P wave duration (Pmax) and the difference between the maximum and the minimum P wave duration, which was defined as P‐wave dispersion (Pdisp) were calculated from the 12‐lead surface ECGs of 75 patients with a history of paroxysmal lone atrial fibrillation and 50 age‐matched healthy controls.Results: Pmax was in patients 122 ± 17 ms and in controls 101 ± 10 ms (t = 7.935, P > 0.001). Pdisp was in patients 48 ± 16 ms and in controls 29 ± 8 ms (t = 7.616, P > 0.001). A Pmax value of 110 ms separated patients from controls with a sensitivity 85%, a specificity 72%, and a positive predictive accuracy of 82%. A Pdisp value of 40 ms separated patients from controls with a sensitivity of 81%, a specificity of 80%, and a positive predictive accuracy of 85%.Conclusions: (1) Pmax and Pdisp values were found to be significantly higher in patients with a prior history of paroxysmal lone atrial fibrillation than in age‐matched healthy controls, and (2) Pdisp is a new simple ECG marker that could be possibly used for the identification of patients with a previous history of paroxysmal lone atrial fibrillation. A.N.E. 1999;4(1):39–45
Usefulness of the P Wave Signal‐Averaged Electrocardiogram in Predicting Patients at Risk of Atrial Flutter and Fibrillation Induced by Transesophageal Pacing
Authors: Banasiak Waldemar , Metner Elwira , Owczarek Irena , Fuglewicz Artur , Anker Stefan D. , Kalka Dariusz , Pieróg Miroslaw , Coats Andrew J.S. , Ponikowski Piotr 
Published: October 2006

Background: Transesophageal pacing (TEP) may be a useful tool in the evaluation of patients with palpitations. The induction of atrial tachyarrythmia by TEP often allows the detection of an underlying re‐entrant atrial arrhythmia as a cause of the patients' symptoms. Recently, the P‐wave triggered signal‐averaged electrocardiogram (SAECG) has been used to detect patients at risk of paroxysmal atrial tachyarrhythmias. The aim of this study was to investigate the usefulness of the P‐wave triggered SAECG applied in a group of patients with a history of paroxysmal palpitations to identify those prone to the development of electrically‐induced atrial flutter or fibrillation.Methods: The study population consisted of 46 patients (31 men, mean age 43 ± 11 years) investigated for palpitations with concomitant symptoms of dizziness or presyncope. Patients were divided into 2 groups according to the presence or absence of an atrial arrhythmia induced by TEP. Twenty‐six consecutive patients (18 men, mean age 44 ± 13 years) demonstrated electrically‐inducible, sustained (lasting < 30 s) atrial fibrillation or atrial flutter (arrhythmia group). The control group comprised 20 patients (13 men, mean age 44 ± 9 years) with similar symptoms, but without significant atrial arrhythmia induced by TEP. The following P‐wave triggered SAECG indices were calculated: the root mean square voltage for the terminal 10, 20, 30 ms of the filtered P‐wave (RMS10,20,30) and time duration of the filtered P‐wave (PWD).Results: Patients with atrial fibrillation or flutter induced by TEP demonstrated significantly longer values of the PWD compared to controls (126.5 ± 15.9 ms vs. 108.0 ± 7.0 ms respectively, P > 0.0001). In the former group we also found the decreased voltage of the terminal part of the P‐wave: RMS10 (4.1 ± 1.1 ptV vs 5.5 ± 2.1 pV, P = 0.002), RMS20 (5.1 ± 1.4 μ V vs. 7.3 ± 2.6 μ V, P = 0.0007), and RMS30 (6.2 ± 1.8 μ V vs. 8.7 ± 2.5 μ V, P = 0.0003) (all comparisons arrhythmia group vs controls, respectively). Moreover, a value of PWD < 117 ms appeared to have practical value in the detection patients at risk of atrial fibrillation or flutter induced by TEP, with a specificity of 90%, sensitivity of 77%, and positive predictive value of 91%.Conclusion: We conclude that among patients presenting with paroxysmal palpitations the P‐wave triggered SAECG had practical value as an noninvasive method to identify those at risk of electrically‐inducible atrial fibrillation and flutter. To what extent this could improve the management of these patients merits further evaluation. A.N.E. 1999;4(1):46–52
Double‐Blind Comparison of Cibenzoline Versus Flecainide in the Prevention of Recurrence of Atrial Tachyarrhythmias in 139 Patients
Authors: Babuty D. , Maison‐Blanche P. , Fauchier L. , Brembilla‐Perrot B. , Medvedowsky J.L. , Bine‐Scheck F. 
Published: October 2006

Background: The efficacy and safety of antiarrhythmic drugs for the prevention of atrial arrythmias are controversial because previous studies were nonrandomized or involved nonselected patients. The aim of this study was to evaluate the efficacy and tolerance of two Class I antiarrythmic drugs, cibenzoline, and flecainide, for the treatment of atrial arrhythmias in carefully selected patients.Patients and Methods: One hundred thirty‐nine patients suffering from documented atrial arrhythmias (mean age 63 ± 12 years, 80 males, 59 females) were enrolled in randomized, double‐blind, parallel clinical trials. Seventy patients received cibenzoline and 69 received flecainide; they were followed for a period of 6 months. All patients had good systolic ventricular function. The recurrence of atrial arrhythmias was diagnosed on symptoms, resting ECG, and 24‐hour ambulatory ECG 3 and 6 months after commencing treatment.Results: Twenty‐seven patients were withdrawn during the study, 13 for adverse side effects, 4 for proarrhythmic effects, and 3 for medical events; 7 were lost to follow‐up. Forty‐three patients had one recurrence of atrial arrhythmias (23 in the cibenzoline group, 20 in the flecainide group). The cumulative percentage of patients free from recurrence was not significantly different in either group at 6 months (63.7% in the cibenzoline group and 66.8% in the flecainide group). Cardiac adverse side effects were more frequent with flecainide than cibenzoline (5 vs. 2). One atrial proarrhythmic effect was observed.Conclusion: Cibenzoline and flecainide are both Class I antiarrhythmic agents which are well tolerated and may be safely administered to prevent alrial arrhythmias. A.N.E. 1999;4(1):53–59
Right Ventricular Dysplasia: A Report of 24 Adult Cases
Authors: MARCUS FRANK I. , FONTAINE GUY H. , GUIRAUDON GERARD , FRANK ROBERT , LAURENCEAU JEAN L. , MALERGUE CHRISTINE , GROSGOGEAT YVES 
Published: October 2006

SUMMARYRight ventricular dysplasia is characterized by an abnormality in the development of part of the right ventricular musculature. Patients with right ventricular dysplasia may present with ventricular tachycardia, suprgventricular arrhythmias, right‐heart failure or asymptomatic cardlomegaly. Twenty‐two adult patients with right ventricular dysplasia who had recurrent ventricular tachycardia were seen during a 7‐year period. The male/female ratio was 2.7:1. The mean age at the time of hospitalization was 39 years. All but one of the patients had ventricular tachycardia of a left bundle branch block configuration. With few exceptions, the T waves were inverted over the right precordial leads. The heart was usually enlarged and the pulmonary vasculaturc was usually normal. In six patients who had two‐dimensional echocardiograms, all showed increased right ventricular diastolic dimensions. All patients had right ventricular angiography; the diagnosis of right ventricular dysplasia was substantiated during surgery in 12 patients and at autopsy in another. Two other patients who did not have arrhythmias had right ventricular dysplasia diagnosed by right‐ and left‐heart angiography.Our unique experience, when combined with a literature review of 34 adult cases, permits a composite clinical profile of this condition in the adult.