bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of a New Device for Diagnosis of Hypoxemia and Arrhythmia by SaO2 ECG Holter Monitoring
Authors: Nakamoto Takaaki , Momoki Shigeru , Harasawa Hiroshi , Ohnuma Noboru , Kato Shiro , Hase Tatsuya , Kuga Hideyo , Kishiro Izumi , Ohno Kunihiko , Suzuki Hidehiko , Tokoyama Kouki , Okamoto Shingo , Takasaki Keiji , Saitoh Koh‐ichi , Tamamura Kazuki , Abe Tetsuro , Iizuka Masahiko 
Published: October 2006

Background: We have developed a system to monitor, simultaneously and continuously, ambulatory SaO2 measured using a pulse‐oximeter and ECG data for 24 hours.Methods: The ambulatory SaO2‐ECG monitoring system consisted of a portable monitoring device (SM50) with two channels for ECG data and one channel for SaO2 data input; a sensor for SaO2 recording; and a pulse‐oximeter. An ambulatory monitoring analyzer was used. The SaO2 report from the present analyzer included two types of data (i.e., a profile of heart rate [HR], pulse rate [PR], and SaO2 value per min), and a trend graph of HR, arrhythmia, ST level and slope, PR, and SaO2 per minute. We also designed and produced an analytical program to automatically remove noise errors relating to the SaO2 measurement.Results: Using this system, we performed a clinical study on ten healthy volunteers (Group N) and seven patients with chronic pulmonary diseases (Group CPD) to evaluate the usefulness of the system as a diagnostic means for respiratory failure and arrhythmia. Group N showed a stable value of 90% or over in SaO2 during the 24‐hour monitoring while Group CPD showed values under 90% SaO2 in all patients at rest during the night or after a 15‐minute walk. Transient atrial tachycardia (TAT) was observed in 3 of 7 CPD patients, and each episode was preceded by a decrease of SaO2. The occurrence of a single or double ventricular extrasystole was high in Group CPD compared with Group N (1.21 ± 0.89 vs 0.6%± 0.3%, P < 0.05), its occurrence was not associated with a decrease in SaO2.Conclusions: In outpatients, especially patients who are taken care of at home, the present system will certainly contribute greatly to the diagnosis of respiratory failure and arrhythmia as well as to evaluate the effects on these diseases of therapy. In addition it is suggested that in CPD, patients’hypoxemia may induce TAT.
ECG Diagnosis of Coronary Artery Disease
Authors: Frogner Fredrik J. , Juul‐Möller Steen 
Published: October 2006

Objective: In order to assess the diagnostic accuracy of ST depression in the diagnosis of coronary artery disease (CAD) in patients with suspected myocardial ischemia we compared ST depression in 3‐lead ambulatory ECG (AECG) with that of exercise tolerance testing (ETT).Methods: Significant coronary artery stenosis in coronary angiography was used as a standard reference. ST analysis could be performed in 106 of the investigated 113 patients, all with suspected CAD. One person with left bundle branch block was excluded from the ST analysis, and six persons could not perform ETT.Results: Seventy‐eight of the 106 patients had at least one significant stenosis (> 70% narrowing) and 28 had no stenosis according to coronary angiography. The sensitivity for AECG was 62% and for ETT it was 63%, the specificity for AECG was 79% and for ETT the specificity was 57%. The accuracy for AECG was 66%, and for ETT it was 61%. We also evaluated late potentials (LPs) from the AECG tapes in order to correlate LP to left ventricular function (LVF), myocardial infarction (Ml), and/or CAD. We found that LP correlates better to advanced CAD than to Ml or LVF.Conclusion: The accuracy of ST diagnosis of CAD in patients with suspected myocardial ischemia using AECG was equal to that of a maximal ETT. LP finding from an AECG tape may support the argument for CAD in patients with ST depressions at AECG.
The Correlation Dimension of Heart Rate Variability Reflects Cardiac Autonomic Activity
Authors: Kamen Peter Walter , Krum Henry , Tonkin Andrew Maxwell 
Published: October 2006

Background: Linear methods of time series analysis such as summary statistics and frequency‐domain parameters have been used to measure heart rate variability (HRV). More recently, nonlinear methods including the correlation dimension (CDim) have been used to evaluate HRV. The aim of this study was to examine the effect of autonomic perturbations on the CDim.Methods: The CDim was calculated from 2000 data points (RR intervals) collected over a relatively short period of time (20–40 min) in 12 healthy subjects aged between 20 and 40 years (mean 30 ± 2 years) during: (a) supine rest; (b) head up tilt (sympathetic activation, parasympathetic nervous system activity withdrawal); (c) intravenous infusion of atropine (parasympathetic nervous system activity withdrawal); and (d) following overnight administration of low dose transdermal scopolamine (parasympathetic nervous system augmentation.Results: The CDim was determined at rest (7.8 ± 0.3) and found to be significantly reduced during tilt (5.9 ± 0.4, P < 0.01) and atropine administration (4.2 ± 0.4, P < 0.01) and possibly increased by scopolamine (8.3 ± 0.5, NS).Conclusions: The changes following these interventions suggest that CDim can accurately measure cardiac autonomic nervous system activity.
QRST Isointegral Map in Dilated Cardiomyopathy
Authors: Kawakami Yoshihide , Sakai Yasuhiko , Shimada Satoshi , Nagao Hikaru , Hirota Yuzo , Kawamura Keishiro 
Published: October 2006

Objective: To investigate the clinical significance of the QRST isointegral map in patients with dilated cardiomyopathy (DCM).Methods: We performed body surface mapping, signal‐averaged ECG, and 201TI myocardial imaging in 41 patients with DCM. Using the QRST I‐sub map, we derived the two parameters of the number of lead points below −2 standards of deviation for the normal nSub value and the absolute value of the Dimin.Results: LPs were detected in 17 patients (41%). The QRST I‐sub map disclosed an abnormal negative area in most of the 41 patients. Both nSub and Dlmin values were larger in the group with LP than in the other group (P < 0.01). Significant inverse correlation was detected between the root mean square voltage in the last 40 ms (index of LP) and the Dlmin value (r =−0.435, P < 0.001). The abnormal scintigraphic patterns were classified into three groups with decreased uptake in the anteroseptal, inferoapical, and postero‐lateral regions, the localizations of which were well‐matched to the minimal points on the QRST I‐sub map (F‐G 4, G‐H 2, and I‐J 3–4, respectively). There was also a close correlation between the myocardial perfusion abnormalities and the distribution of the −2SD area on the QRST I‐sub map.Conclusion: The QRST isointegral map is useful in detecting the extent and localization of the myocardial damage in patients with DCM.
Predictive Value of Late Potentials after Myocardial Infarction in the Thrombolytic Era
Authors: Bruna Claudio , Vado Antonello , Rossetti Guido , Racca Emanuela , Ferrero Valeria , Cherasco Elvira , Fantino Ivana , Isoardi Daniela , Uslenghi Eugenio 
Published: October 2006

Background: The value of the signal‐averaged electrocardiogram (ECG) for prediction of arrhythmic events (AE) after myocardial infarction (MI) has been well established. The current incidence of AE in the first year after Ml is remarkably lower than that reported in the 1980s. In this study, we compared the prevalence and the predictive value of late potentials (LP) in patients with Ml treated with either conventional or reperfusion therapy.Methods: A total of 433 patients (age 62 ± 10 years, 350 men) recovering from acute Ml were prospectively analyzed. Two hundred seven patients had conventional therapy (group A), and 226 had reperfusion therapy (group B) within 12 hours of the onset of symptoms: 145 of group B patients received thrombolytic agents, whereas 81 underwent direct or rescue angioplasty. Standard signal‐averaged variables were recorded (filter range 40–250 Hz) 10 ± 6 days (range 5–30 days) after Ml. LP were defined as being present if 2 of the following were met: fQRS <114 ms, RMS40 20 μV, LAS40 <38 ms (criterion 1), and if QRS 120 ms (criterion 2).Results: LP were found in 33% versus 21%, P = 0.004 (criterion 1) and in 13% versus 8%, P = 0.057 (criterion 2) of group A and group B patients, respectively. During a mean follow‐up of 24 ± 19 months (range 5 days to 48 months), there were 22 AE (5%). The AE rate for patients with conventional therapy was significantly higher in those with LP than in those without LP: 12% versus 4%; P = 0.03 (criterion 1) and 30% versus 3%; P = 0.00003 (criterion 2). The AE rate for patients with reperfusion therapy was similar in patients with and without LP: 9% versus 3%, P = 0.09 (criterion 1) and 12% versus 3%, P = 0.14 (criterion 2). Multivariate analysis indicated that the presence of LP based on criterion 2 was the strongest independent predictor of AE in patients with Ml treated with conventional therapy.Conclusion: In this study, reperfusion therapy influenced the prevalence of LP. The predictive value of LP for serious AE in the postinfarction period was remarkably affected by thrombolysis and/or interventional catheter therapy.
QT Dynamics from Holter Recordings: A Comparison of Two Averaging Methods
Authors: Kluge Petra , Rose Ekkehard , Meyer Claudia , Wittig Kathrin , Walter Thomas , Neugebauer Annerose , Pfeiffer Dietrich 
Published: October 2006

Background: QT dynamics is the adaptation of repolarization duration on heart rate. There are several automatic computer algorithms for Holter analysis to describe this process. Our study was performed to compare results of two averaging algorithms inherent in an automatic Holter QT module.Methods: Two different methods of the automatic QT module of the ELATEC system were applied to digitized Holter ECGs of 50 healthy men. The first method, “QT/RR,” calculates the linear regression up to 2880 mean QT intervals (values over 30 s) and corresponding RR intervals containing the preceding 60 seconds of the QT value and the 30 seconds while QT averaging. The second method, “QT/RR class,” correlates the averaged QT duration over the corresponding 25‐ms RR interval classes. Possible differences in rate adaptive behavior between two portions of QT duration were of further interest.Results: The main result of the study was that the linear regression obtained by the “QT/RR” method was slightly, but significantly, steeper than those obtained by the “QT/RR class” method.Conclusion: Rate adaptation of QTe and QTa is the same if measured by one particular method. Studying the same population using different averaging methods leads to different results. In contrast to the “QT/RR” method, “QT/RR class” method leads to an overestimation of extreme and rare RR values. Therefore, results of “QT/RR class” method cannot be used as a surrogate for “QT/RR” methods.
Change of QT Dispersion After PTCA in Angina Patients
Authors: Choi Kee‐Joon , Lee Cheol‐Whan , Kang Duk‐Hyun , Song Jae‐Kwan , Kim Jae‐Joong , Park Seong‐Wook , Park Seung‐Jung , Park Chong‐Hun , Kim You‐Ho 
Published: October 2006

BackgroundQT dispersion (QTd) represents the inhomogeneity of ventricular repolarization and has been reported to predict ventricular tachyarrhythmias in postmyocardial infarction patients. This study investigates the short‐term effect of percutaneous transluminal coronary angioplasty (PTCA) on QTd in patients with coronary artery disease (CAD) and no history of previous myocardial infarction.MethodsIn 84 angina patients (65 men and 19 women, mean age, 58.3 ± 9.0 years) who underwent successful PTCA of a single coronary artery, ECG was recorded in baseline, immediate, 1 day, and 1 month after PTCA for measurement of QTd and corrected QTd (c‐QTd).ResultsPTCA was performed at the left anterior descending artery (LAD) in 56, left circumflex artery (LCx) in 12, and right coronary artery (RCA) in 16 patients. QTd (c‐QTd) at baseline, immediately, 1 day, and 1 month following PTCA was 51.3 ± 4.2 (50.7 ± 4.1), 54.2 ± 4.5 (52.8 ± 4.5), 47.7 ± 4.3 (48.5 ± 4.8), and 36.3 ± 4.5 (37.5 ± 4.6) ms, respectively. QTd and c‐QTd significantly decreased at 1 month following PTCA. The difference was more prominent in patients with LAD lesion than LCx or RCA lesion, independent of gender, severity of stenosis, and use of beta‐blocker.ConclusionsQTd decreases in CAD patients with no history of myocardial infarction at 1 month following successful PTCA. This suggests that PTCA facilitates a favorable recovery from inhomogeneous repolarization due to myocardial ischemia. This finding calls for long‐term follow‐up of QTd and risk of ventricular tachyarrhythmias and sudden death following successful PTCA.
Abnormal QT Dispersion Predicts Unexpected Sudden Death in Young Patients with Thalassemia Major
Authors: Cuomo Sergio , Mayer Maria C. , Comoletti Carmela , D'Onofrio Antonio , Buffardi Salvatore , Russo Vittorio 
Published: October 2006

Background:QT interval dispersion has been proposed as a simple noninvasive predictor of ventricular arrhythmias and sudden death. Patients with thalassemia major are at increased risk for sudden death. However, the independent effect of increased QT dispersion on the risk of sudden death in thalassemia major is not known. This study sought to test the hypothesis that an abnormal QT dispersion predicts sudden death in patients with thalassemia major. Methods:QT dispersion was measured in 13 consecutive patients with thalassemia major who had sudden death at a mean age of 16.1 ± 2.8 years, and in 13 survivors matched for age, gender, examination year, and transfusion therapy. Results:Patients who died suddenly had significantly greater QT dispersion (59 ± 29 ms) than patients who survived (29 ± 13 ms; P = 0.002). A cut‐off value of 50 ms for QT dispersion had a sensitivity of 54%, a specificity of 92%, a positive predictive value of 87%, a negative predictive value of 67% and a predictive accuracy of 73% in identifying patients at risk of sudden death. With multiple regression analysis, QT dispersion was the only independent predictor of sudden death. Conclusions:QT dispersion is a useful marker of risk of sudden death in patients with thalassemia major. A.N.E. 1999;4(3):295–300
Determinants of Efficacy of Beta‐Blocker Therapy in Patients with Asystole Induced During Head‐up Tilt Testing
Authors: Kouakam Claude , Lacroix Dominique , Vaksmann Guy , Klug Didier , Jarwe Moustapha , Mairesse Georges , Key Christian , Kacet Salem 
Published: October 2006

Background:The prognosis and treatment of patients with prolonged asystole during head‐up tilt test (HUT) remain controversial. The aim of this study was to identify factors predicting a favorable outcome in patients with unexplained syncope who have an asystolic response during HUT. Methods:Passive HUT was performed at 60° for up to 45 minutes in 329 patients (162 women and 167 men, mean age 38 ± 22 years). Isoproterenol was given in escalating doses when passive HUT was negative. Asystole was defined as a ventricular pause 5 seconds. Results:Among the 173 patients with positive HUT, 21 developed syncope related to asystole (mean duration 13 ± 7.5 seconds). According to our initial experience, beta‐blocker therapy was used as a first line treatment. At repeat HUT on beta blockers, 16 patients (group I) were partially (n=5) or totally (n=11) controlled by beta blockers, as opposed to 5 patients (group II) in whom asystole remained inducible. Three of them required implantation of a pacemaker and the two others refused. When compared to group I patients, group II patients were older (50 ± 9 vs 24 ± 10 years, P < 0.001) and had a longer asystole duration (22 ± 7 vs 10 ± 5 seconds, P < 0.005) during initial HUT, while spontaneous clinical manifestations were identical. The diagnostic accuracy to predict failure of beta blockers was 83% for age > 40 years, 80% for asystole > 15 seconds and 100% for both. After a follow‐up of 35 ± 11 months, the two patients of group II who refused pacemaker, experienced recurrence of syncope, while the three others remained free of symptoms. Concerning group I, patients successfully managed were asymptomatic, and few episodes of recurrent presyncope were observed in only four of those partially controlled by beta blockers. Conclusions: Prolonged asystole (> 15 seconds) and an older age (> 40 years) both predict a poor response to beta‐blocker therapy in patients with vasovagal syncope referred to as malignant. Satisfactory HUT under beta blockers predict a favorable clinical outcome. A.N.E. 1999;4(4):377–384
Adequacy of an Exercise Test in Excluding Angina on Patients Presenting to the Emergency Department with Chest Pain
Authors: Senaratne Manohara P.J. , Carter Debbie , Irwin Marleen 
Published: October 2006

Background:The clinical utility and cost effectiveness of exercise testing (ET) following evaluation by a cardiologist to exclude angina in patients presenting to the emergency department (ED) with chest pain was evaluated. Methods:Patients presenting to the ED with no apparent cause were evaluated. Of 239 patients presenting to the ED with chest pain without a history of coronary artery disease, 23 underwent sestamibi scanning with 216 undergoing ET. Follow‐up evaluation was performed by telephone. Results:Of 216 ETs, 168 (77.8%) were negative, 24 (11.1%) positive, 24 (11.1%) indeterminate (209 discharged home directly). During follow‐up (mean 20 months: range 5–37) there were three noncardiac deaths (malignancies = two, pneumonia = one) with five patients diagnosed with angina among the 168 with negative tests. Forty‐two patients indicated unscheduled return visits (ED = 15, physician's office = 23, admissions = 4). The present management strategy realized a saving of Canadian (Cdn). $86,585.60 when compared with sestamibi scanning as the primary test. Conclusions: ET following an evaluation by a cardiologist can be used for the initial screening of patients presenting with chest pain to the ED with a high negative predictive accuracy with regard to future coronary events. Nuclear perfusion imaging can be used in a minority of patients where an ET is not feasible. A.N.E. 1999;4(4):408–415
Correlation Method for Detection of Transient T‐Wave Alternans in Digital Holter ECG Recordings
Authors: Burattini Laura , Zareba Wojciech , Moss Arthur J. 
Published: October 2006

Background:Spectral and complex demodulation methods for detection of microvolt T‐wave alternans (TWA) have limited ability to identify transient (nonstationary) TWA episodes. We aimed to develop and test new time‐domain technique allowing TWA detection and quantification in as few as 7 consecutive beats from sinus rhythm ECGs. Methods and results:Quantification of TWA during sinus rhythm required preprocessing consisting of: low‐pass filtering, RR stability testing, baseline and respiratory modulation removal, and T‐wave windowing and synchronization. Our time‐domain correlation method (CM) detects TWA by computing, for each consecutive T wave, an alternans correlation index based on a crosscorrelation technique. CM allows quantitative analysis of the amplitude, duration, and overall magnitude of the TWA episode. The technical performance of CM was confirmed in testing with simulated TWA of varying amplitude, duration, and noisy conditions. The clinical performance of CM was demonstrated by analyzing digital Holter recordings of 39 long QT syndrome patients compared to 36 healthy subjects. CM identified TWA in 17 (44%) patients with nonstationary TWA detected in 8. Conclusion:Our computer algorithms consisting of ECG preprocessing and TWA quantification by the correlation method provides the opportunity to detect nonstationary and stationary TWA in sinus rhythm of digital Holter ECG recordings. A.N.E. 1999;4(4):416–424
Localized Right Precordial QRS Prolongation as the Basic ECG Finding in Arrhythmogenic Right Ventricular Dysplasia Cardiomyopathy
Authors: Peters Stefan , Getting Bettina , Peters Heidi 
Published: October 2006

Background: Since the first description of arrhythmogenic right ventricular dysplasia (ARVD) in 1977 several attempts have been made to find the ideal diagnostic technique. Localized QRS prolongation in right precordial leads gained general interest in 1993, although the definition and value of this diagnostic criterion is not well established.Method: In different cohorts of patients (93 healthy volunteers, 84 patients with task‐force criteria of ARVD, 54 patients with dilated cardiomyopathy, and 16 patients with hypertrophic cardiomy‐opathy) QRS duration was measured in precordial leads in standard ECGs with a paper speed of 50 mm/s. Two different ECG algorithms were used to differentiate ARVD: (a) QRS duration in V1, V2, or V3 < 110 ms and (b) QRS duration in (V1 + V2 + V3)/(V4 + V5 + V6) < 1.2. The frequency of right precordial T wave inversions, incomplete and complete RBBB, and left ventricular hypertrophy was analyzed in addition.Results: The frequency of right precordial T inversions in ARVD was moderately high (64%), the frequency of incomplete RBBB (n = 2), complete RBBB (ri = 6), and left ventricular hypertrophy (n = 1) was low. A QRS duration 2 110 ms in right precordial leads was found in 80% with an overall specificity of 89%. The ECG feature of outstanding importance was a ratio of QRS duration in (V1 + V2 + V3)/(V4 + V5 + V6) == 1.2, which was present in 97% with a specificity of 100%.Conclusions: Localized right precordial QRS prolongation best defined as a QRS duratio ratio in (V1 + V2 + V3)/(V4 + V5 + V6) s 1.2 seems to be a sensitive and specific finding in ARVD even in cases with incomplete or complete RBBB and, at least, in one case with left ventricular hypertrophy. Other forms of cardiomyopathies with certain right ventricular involvement and a control group of healthy volunteers can be differentiated with outstanding safety.
Interlead Difference in QT Interval Rate Adaptation During Exercise in Coronary Artery Disease Patients Susceptible to Ventricular Fibrillation
Authors: Oikarinen Lasse , Toivonen Lauri , Viitasalo Matti 
Published: October 2006

Background: Nonhomogeneity in ventricular repolarization predisposes to ventricular tachyarrhythmias. Rate adaptation of the QT interval parallels rate adaptation of the action potential, both of which reflect the repolarization phase in ventricular myocardium. The aim of this study was to examine in patients with coronary artery disease (CAD) the relation of interlead differences in QT interval rate‐adaptation to arrhythmia vulnerability.Methods: We studied 29 CAD patients with a history of ventricular fibrillation (VF) not associated with acute myocardial infarction (VF group), and their 29 individually matched CAD controls without arrhythmic events (controls). Rate adaptation of the QT intervals in the 12 leads of the electrocardiogram were determined from QT intervals measured at rest and at the end of each 3 minute load step during exercise test. The relation between heart rate (HR) and QT interval (QT/HR slope) was calculated separately in each lead by the linear regression equation. The slopes of these equations were used to characterize spatial QT interval rate adaptation.Results: The steepest QTapex/ HR slopes in any lead were (mean ±mD SD) −2.45 ± 0.63 in the VF group and ‐1.97 ± 0.45 in controls (P = 0.008), whereas the smallest slopes showed no difference (P = NS). The standard deviations of QTapex/ HR slopes were 0.48 ± 0.23 in the VF group and 0.33 ± 0.12 in controls (P = 0.012).Conclusions: Rate adaptation of the QTapex interval is locally exaggerated, resulting in nonhomogenous exercise response of the QTapex intervals in CAD patients susceptible to life‐threatening ventricular arrhythmias. A.N.E. 2000;5(4):346–353