bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of Myocardial Surgical Revascularization on Left Ventricular Late Potentials
Authors: Can Levent , Kayikçioǧlu Meral , Halil Halil , Kültürsay Hakan , Evrengül Harun , Kumanlioǧlu Kamil , Turkoglu Cüneyt 
Published: October 2006

Background: The presence of ventricular late potentials (LP) is an important indicator for the development of ventricular tachyarrhythmias due to ischemic heart disease. The effect of myocardial revascularization on LP has remained controversial. The purpose of this study was to determine whether complete myocardial surgical revascularization (CABG) documented by myocardial perfusion scintigraphy might alter the substrate responsible for LP.Methods: Prospectively, enrolled patients undergoing elective CABG were evaluated with thallium‐201 myocardial perfusion scintigraphy and signal‐ averaged ECG pre‐ and postoperatively. SAECG recordings were obtained serially: before, 48–72 hours and 3 months after CABG. LPS were defined as positive if SAECG met at least two of Gomes criteria. Scintigraphies were performed pre‐and 3 months postoperatively for determination of the success of revascularization. Changes observed in SAECG recordings after CABG were compared between those with and without successful revascularization.Results: CABG resulted in successful revascularization in 23 patients and was unsuccessful in 17 (no change or deterioration of the perfusion defects). Preoperative SAECG values were not different between groups except for RMS values. The incidence of LP decreased significantly postoperatively in patients with improved myocardial perfusion, whereas there were no changes in patients who did not have postoperative perfusion improvement (McNemar test, P < 0.05).Conclusions: LPs disappear following the elimination of myocardial ischemia by complete surgical revascularization. Persistence of ischemia following CABG usually results in the persistence of late potentials. The incidence of ventricular arrhythmias is expected to be unchanged in these patients and they should be reevaluated for reinterventions. A.N.E. 2001;6(2):84–91
Effect of Beta‐Blockade on Autonomic Modulation of Heart Rate and Neurohormonal Profile in Decompensated Heart Failure
Authors: Aronson Doron , Burger Andrew J. 
Published: October 2006

Background: One of the putative mechanisms for the salutary effects of beta‐blockers in patients with congestive heart failure (CHF) is their ability to improve autonomic dysfunction. However, patients with profound neurohumoral abnormalities derive little survival benefit from beta‐blockers. The purpose of the current study was to evaluate the effect of beta‐blockers on heart rate variability (HRV) in decompensated CHF.Methods: Time and frequency domain HRV indices were obtained from 24‐hour Holter recordings and compared to assess the role of beta‐blockade in 199 patients (mean age 60 ± 14 years) with decompensated CHF. Neurohormonal differences were assessed by measuring norepinephrine, endothelin‐1, tumor necrosis factor‐a, and interleukin‐6 in a subset of 64 patients.Results: All HRV indices were markedly suppressed but were substantially higher in patients who were on beta‐blockers. Time domain measures of parasympathetic cardiac activity, the percentage of R‐R intervals with > 50 ms variation (4.9 ± 0.6 vs 7.7 ± 1.2%, P = 0.006) and the square root of mean squared differences of successive R‐R intervals (22.7 ± 2.0 vs 31.6 ± 4.1 ms, P = 0.004), were higher in the beta‐blocker group. Spectral analysis revealed that the total power and the ultra‐low frequency power were significantly higher in patients on beta‐blockers (82% and 59%, respectively). The high frequency power, a spectral index of parasympathetic modulation, was 41% higher in the beta‐blocker group (121 ± 25 vs 171 ± 27 ms2, P = 0.02). Norepinephrine and interleukin‐6 levels were substantially lower in patients on beta‐blockers (28% and 61%, respectively). However, these differences did not reach statistical significance.Conclusions: Beta‐blockers improve the impaired cardiac autonomic regulation during high sympathetic stress of decompensated CHF. This effect may play an important role in protecting the myocardium and preventing arrhythmias during transient increases in sympathetic activity. A.N.E. 2001;6(2):98–106
Differences in Heart Rate Dynamics Before the Spontaneous Onset of Long and Short Episodes of Paroxysmal Atrial Fibrillation
Authors: Vikman Saila , Yli‐Mäyry Sinikka , Mäkikallio Timo H. , Airaksinen K.E. Juhani , Huikuri Heikki V. 
Published: October 2006

Background: Altered heart rate (HR) dynamics precede the spontaneous onset of atrial fibrillation (AF), but the factors related to the perpetuation and duration of paroxysmal AF episodes are not well established. This study was designed to test the hypothesis that HR dynamics preceding the onset of (AF) may influence the duration of AF.Methods: Traditional time and frequency domain HR variability indices, along with a short‐term fractal scaling exponent (α1) and approximate entropy (ApEn), were analyzed in 20‐minute intervals before 92 episodes of spontaneous paroxysmal AF in 22 patients without structural heart disease. AF episodes were divided into two groups according to the duration of the arrhythmia episodes.Results: The high‐frequency (HF) spectral component in normalized units (nu) of heart rate variability was higher and low‐frequency (LF) component lower before long (> 200 s, n = 41) compared to short (< 200 s, n = 51) AF episodes (HF nu; 40.1 ± 14.8 vs 31.5 ± 16.4, P < 0.0001 and LF nu; 59.9 ± 14.8 vs 68.5 ± 16.4, P < 0.0001). Short‐term scaling exponent values also were lower before long compared to short AF episodes (e.g., α1; 1.12 ± 0.21 vs 1.24 ± 0.23, P < 0.0001). Women had a larger number of long AF episodes than men, but the duration of AF was not related to any other clinical or demographic features or antiarrhythmic medication.Conclusion: Increased HF oscillations and decreased short‐term correlation properties of R‐R intervals, reflecting altered sympathovagal balance before the onset of AF, predispose to perpetuation of spontaneous arrhythmia episodes in patients with vulnerability to paroxysmal AF and without structural heart disease. A.N.E. 2001;6(2):134–142
P‐Wave Dispersion: A Novel Predictor of Paroxysmal Atrial Fibrillation
Authors: Dilaveris Polychronis E. , Gialafos John E. 
Published: October 2006

Background: The prolongation of intraatrial and interatrial conduction time and the inhomogeneous propagation of sinus impulses are well known electrophysiologic characteristics in patients with paroxysmal atrial fibrillation (AF). Previous studies have demonstrated that individuals with a clinical history of paroxysmal AF show a significantly increased P‐wave duration in 12‐lead surface electrocardiograms (ECG) and signal‐averaged ECG recordings.Methods: The inhomogeneous and discontinuous atrial conduction in patients with paroxysmal AF has recently been studied with a new ECG index, P‐wave dispersion. P‐wave dispersion is defined as the difference between the longest and the shortest P‐wave duration recorded from multiple different surface ECG leads. Up to now the most extensive clinical evaluation of P‐wave dispersion has been performed in the assessment of the risk for AF in patients without apparent heart disease, in hypertensives, in patients with coronary artery disease and in patients undergoing coronary artery bypass surgery. P‐wave dispersion has proven to be a sensitive and specific ECG predictor of AF in the various clinical settings. However, no electrophysiologic study has proven up to now the suspected relationship between the dispersion in the atrial conduction times and P‐wave dispersion. The methodology used for the calculation of P‐wave dispersion is not standardized and more efforts to improve the reliability and reproducibility of P‐wave dispersion measurements are needed.Conclusions: P‐wave dispersion constitutes a recent contribution to the field of noninvasive electrocardiology and seems to be quite promising in the field of AF prediction. A.N.E. 2001;6(2):159–165
The Normal Sequence of Right and Left Atrial Contraction
Authors: Barletta Giuseppe , Del Bene Riccarda , Fantini Fabio 
Published: October 2006

Objective: To study the sequence of atrial activation and the interatrial electromechanical delay (IEmD) noninvasively in healthy subjects during sinus rhythm (SR).Methods and Results: In 66 SR healthy subjects P‐wave activation was analyzed by means of vectorcardiography. The timing of atrial contractions was measured as the intervals between the P‐wave and the A‐wave of the Doppler right and left ventricular inflows (P‐At and P‐Am), and IEmD was calculated as the algebraic difference PAm P‐At. In the horizontal plane the vectorcardiographic P‐loop was anteroposterior (“typical”, 41 subjects), anterior (18), or posterior (7). IEmD (mean ±; SE 17 ±; 8 ms) was directly related to R‐R and P‐R intervals. IEmD was significantly shorter in anterior and posterior P loops than in the typical (6.5 ±; 5.3 and 8.1 ±; 10.1, respectively, vs 24.2 ±; 3.1 ms). In the posterior P‐loop group, who exhibited longer P‐At, mitral E‐wave velocity and E/A ratio were reduced, and left atrial booster function was increased.Conclusion: IEmD was widely variable in SR, reflecting the origin site of sinus impulse, which independently influenced ventricular filling dynamics. A.N.E. 2001;6(3):222–228
QRS Score: A Composite Index of Exercise‐Induced Changes in the Q, R, and S Waves During Exercise Stress Testing in Patients with Ischemic Heart Disease
Authors: Toth Ambrus , Marton Zsolt , Czopf Laszlo , Kesmarky Gabor , Halmosi Robert , Juricskay Istvan , Habon Tamas , Toth Kalman 
Published: October 2006

Background: To detect ischemic heart disease, the exercise‐induced ST‐segment displacement is the most frequently used ECG parameter. However, the value of this marker was proven to be limited with varying sensitivity and specificity. A new parameter, called QRS score, emerged to improve the efficacy of exercise testing.Methods: Our study aimed at evaluating the diagnostic value of QRS score in ischemic heart disease, investigating males and females separately, and examining the effects of heart rate and antiischemic medication. QRS score and cumulative ST depression were calculated in 212 patients and correlated to the findings of the stress myocardial perfusion SPECT (197 subjects) or coronary angiography (54 subjects).Results: An inverse correlation could be found between the QRS score and the results of myocardial SPECT and coronary angiography in the whole population, especially in males; females did not show a significant relationship. In patients with conclusive tests (achieving 85% of the maximal predicted heart rate) QRS score correlated significantly with the results of the stress myocardial perfusion SPECT and coronary angiography. The sensitivity, specificity, and validity of the QRS score surpassed those of the cumulative ST depression in the entire population as well as in patients with conclusive tests. The antiischemic medication did not affect correlation values.Conclusion: QRS score was significantly related to the extent of myocardial ischemia and the severity of coronary heart disease, thus along with the analysis of ST‐segment displacement may contribute to the more precise evaluation of exercise testing. A.N.E. 2001;6(4):310–318
The Prognostic Accuracy of Different QT Interval Measures
Authors: Lund Kaspar , Perkiömäki Juha S. , Brohet Christian , Elming Hanne , Zaïdi Mohammed , Torp‐Pedersen Christian , Huikuri Heikki V. , Nygaard Hans , Kirstein Pedersen Anders 
Published: October 2006

Background: The QT intervals accuracy for predicting arrhvthmic death varies between studies, possibly due to differences in the selection of the lead used for measurement of the QT interval. The purpose of this study was to analyze the prognostic accuracy of all known ways to select the lead.Methods and Results: Three institutions that used different methods for measuring QT intervals provided their QT databases. They included more than 3500 twelve‐lead surface ECGs. The data represented low‐ and high‐risk patients of the normal population (survivors vs dead from cardiovascular causes), acute myocardial infarction (survivors versus death from all causes) and remote myocardial infarction (with vs without a history of ventricular arrhythmia). The prognostic accuracy was defined as the area under the Receiver Operator Curve (ROC‐area). The most accurate standard leads were I and aVL and the least accurate was AVR. The most accurate precordial lead was V4. The prognostic accuracy of the longest QT interval was higher than for any standard lead. The prognostic accuracv of the mean of the three longest QT intervals was equal to or slightly lower than for the longest QT interval.Conclusions: The highest prognostic accuracy is obtained with the longest QT interval. The accuracies of the lead selection methods are so different that it can explain a substantial part of the differences between otherwise similar studies in the literature. We recommend the use of the mean value of the three longest QT intervals. A.N.E. 2002;7(1):10–16
QT Dispersion and Viable Myocardium in Patients with Prior Myocardial Infarction and Severe Left Ventricular Dysfunction
Authors: Hun Li Vuy , Dorbala Sharmila , Narula Dhiraj , DePuey Gordon , Steinberg Jonathan S. 
Published: October 2006

Background: QT dispersion (QTd) has been found to correlate to the amount of viable myocardium in patients with Q‐wave myocardial infarction and well‐preserved LV function. However, this relationship is unknown in patients with severe left ventricular dysfunction.Methods: Thirty‐four patients with prior large myocardial infarction and severe left ventricular dysfunction underwent Tc‐99m sestamibi single photon emission cardiac tomography (SPECT) and F‐18 fluorodeoxyglucose (FDG) SPECT. Viability was defined as a defect relative count density (DCD) of at least 20% greater on FDG SPECT. QTd, corrected QT dispersion (QTcd), and QT coefficient of variation (cv) in patients with viable myocardium was compared to those without viable mvocardium in the infarct area.Results: Thirteen patients were excluded from analysis for poor FDG images or inadequate ECG tracings. Of the remaining patients, 10 (48%) were found to have viability on FDG SPECT. QTd, QTcd, and QTcv in patients with viability were: 58 ± 22 ms, 61 ± 23 ms, and 4.81 ± 1.76%, respectively, which did not differ significantly from those in patients without viability (QTd = 56 ± 14 ms, QTcd = 70 ± 16 ms and Qtcv = 5.06 ± 1.20% (P = NS]). Moreover, neither FDG defect size, nor LVEF correlated with QTd.Conclusions: This study indicates no relationship between QTd and viability in patients with myocardial infarction and severe left ventricular dysfunction. A.N.E. 2002;7(1):53–59
Lack of Impact of Myocardial Ischemia on the Signal‐Averaged ECG Assessment by Time‐Domain Analysis
Authors: Schneider Michael A. E. , Nienaber Christoph A. 
Published: October 2006

Background: Late potentials represent an arrhythmogenic substrate in chronically infarcted myocardium. It is hypothesized that acute transient ischemia enhances anisotropic electrical ventricular activation and facilitates reentry mechanisms. Study aim was the prospective assessment of the impact of dipyridamole‐induced myocardial ischemia on the signal‐averaged ECG.Methods: Dipyridamole stress thallium‐201 SPECT imaging was utilized to avoid noise contamination of the signal‐averaged ECG from exercise and to document evidence and localization of myocardial ischemia or persistent perfusion defects in 68 patients with suspected coronary artery disease. Before and during dipyridamole‐induced vasodilatation serial signal‐averaged ECG was performed to evaluate the influence of transient ischemia on the occurrence of late potentials.Results: There was a significant difference between heart rate at rest and heart rate under dipyridamole influence in patients with inducible ischemia (70 ± 13 vs. 87 ± 13; P < 0.0001) in contrast to patients without dipyridamole‐induced ischemia (74 ± 20 vs. 80 ± 16; n.s.). The number of averaged beats and achieved noise level was comparable between both groups. Thirty‐three of 68 patients (49%) revealed dipyridamole‐induced ischemia; however, no changes of the SAECG parameters, such as QRS, RMS, LAS at 25–250 and 40–250 Hz bandpass filtering in the leads X, Y, Z and vector magnitude, respectively, were observed as a result of ischemia.Conclusion: These results suggest that transient myocardial ischemia does not affect the signal‐averaged ECG. Clinically, the signal‐averaged ECG analysis seems not to be helpful in identifying patients with silent ischemia. A.N.E. 2002;7(3):191–197
Is the Change of Late Potential Over Time Related to Enzyme Levels?Ichemic Burden in Acute Myocardial Infarction
Authors: Eryol Namik Kemal , Topsakal Ramazan , Oguzhan Abdurrahman , Abaci Adnan , Başar Emrullah , Ergin Ali , Çetin Servet 
Published: October 2006

Background: The ventricular late potential (VLP) detected using the technique of signal average electrocardiography (SAECG) interacts with several factors, primarily time.Method: In this study, we examined the interaction, over time, of VLP with the initial ischemic burden and enzyme levels in acute myocardial infarction. Patients diagnosed as having acute myocardial infarction were included in the study. On the first day, the patients underwent enzyme analysis and electrocardiography (ECG) follow‐up every 6 hours. A 24‐hour ambulatory ECG was performed on the seventh day in order to determine the ischemic burden. SAECG findings (TQRS, RMS, LAS were obtained on the seventh day, in the first and third months. The study was continued with the patients who did not require angioplasty as decided with angiographic evaluation in the first month.Results: The study included 30 patients with acute myocardial infarction (mean age 51 ± 12, 28 males and 2 females). The initial mean CK‐MB levels and the mean ischemic burden were 98 ± 31 U/L and 44 ± 96 minutes. The TQRS (ms), LAS (ms), and RMS (μV) values (mean ± SD) obtained at day 7, month 1, and month 3 are 97 ± 12, 96 ± 9, 103 ± 11, P = 0.01; 31 ± 10, 31 ± 11, 32 ± 10, P = 0.46; 43 ± 28, 41 ± 26, 33 ± 25, P = 0.01, respectively. We observed that the TQRS and RMS values changed significantly with time, but these levels of significance disappeared when adjusted for the initial ischemic burden and CK‐MB levels (P = 0.06; P = 0.53). The VLP frequency was 33% at day 7 and 23% at month 3. Unlike the CK‐MB level, the initial ischemic burden was significantly different between the patients with and without VLP at month 3 (150.85 ± 149.28, 12.34 ± 26.48, P = 0.001). When tested together with age and gender, it was found that the high initial ischemic burden increased the possibility of VLP (OR: 24, Cl: 2.09–279.52, P = 0.01) at month 3.Conclusion: SAECG findings in patients with myocardial infarction changed with time; however, this change occurred depending on the initial ischemic burden and CK‐MB levels. Of these, only the initial ischemic burden, especially in high levels, was a determinant for the presence of VLP in the late period of myocardial infarction. A.N.E. 2002;7(3):242–246
Support of Daily ECG Procedures in a Cardiology Department via the Integration of an Existing Clinical Database and a Commercial ECG Management System
Authors: Chiarugi Franco , Lombardi David , Lees Philip J. , Chronaki Catherine E. , Tsiknakis Manolis , Orphanoudakis Stelios C. 
Published: October 2006

Background: In the context of HYGEIAnet, the regional health telematics network of Crete, a clinical cardiology database (CARDIS) has been installed in several hospitals. The large number of resting ECGs recorded daily made it a priority to have computerized support for the entire ECG procedure.Methods: Starting in late 2000, ICS‐FORTH and Mortara Instrument, Inc., collaborated to integrate the Mortara E‐Scribe/NT ECG management system with CAROIS in order to support daily ECG procedures. CARDIS was extended to allow automatic ordering of daily ECGs via E‐Scribe/NT. The ECG order list is downloaded to the electrocardiographs and executed, the recorded ECGs are transmitted to E‐Scribe/NT, where confirmed ECG records are linked back to CARDIS. A thorough testing period was used to identify and correct problems. An ECG viewer/printer was extended to read ECG files in E‐Scribe/NT format.Results: The integration of E‐Scribe/NT and CARDIS, enabling automatic scheduling of ECG orders and immediate availability of confirmed ECGs records for viewing and printing in the clinical database, took approximately 4 man months. The performance of the system is highly satisfactory and it is now ready for deployment in the hospital.Conclusions: Integration of a commercially available ECG management system with an existing clinical database can provide a rapid, practical solution that requires no major modifications to either software component. The success of this project makes us optimistic about extending CARDIS to support additional examination‐procedures such as digital coronary angiography and ultrasound examinations. A.N.E. 2002;7(3):263–270
Adrenergic Nervous System Influences on the Induction of Ventricular Tachycardia
Authors: Pellizzón Oscar A. , Beloscar Juan S. , Mariani Enrique 
Published: October 2006

Background: Sudden cardiac death is a major cause of mortality in western countries and the ventricular tachyarrhythmias are mainly involved in this regard. The adrenergic autonomic nervous system has influences in provoking life‐threatening arrhythmias, and the prevention of such arrhythmias with beta‐blockers supports this viewpoint. To evaluate the effect of the adrenergic nervous system and some catecholamine‐releasing stimuli on the induction of ventricular tachycardia, we decided to explore the occurrence of ventricular tachycardia in patients subjected to three consecutive tests, exercise testing, isoproterenol infusion, and mental stress.Methods: Nineteen subjects who experienced exercise test‐induced ventricular tachycardia were subjected to an isoproterenol infusion and mental stress. All but one patient had cardiac disease, with 70% due to Chagas’disease. Seventeen of the 19 study subjects had normal ventricular function.Results: Exercise test‐induced ventricular tachycardia was nonsustained in 17 patients and sustained in 2 cases. Isoproterenol infusion induced nonsustained ventricular tachycardia in 9 of 19 patients. Mental stress, on its own, was able to induce nonsustained ventricular tachycardia in 2 of 19 patients.Conclusions: Among patients preselected for exercise‐induced ventricular tachycardia, almost half could be induced into ventricular tachycardia by isoproterenol infusion. Mental stress was a less powerful inducer of ventricular arrhythmias in this study group. A.N.E. 2002;7(4):281–288