bluuebunny/crossref_metadata_2025 huggingface dataset:
Inter‐ and Intraday Variability in Major Electrocardiogram Intervals and Amplitudes in Healthy Men and Women
Authors: DOTA CORINA D. , EDVARDSSON NILS , SCHÜTZER KAJS‐MARIE , OLOFSSON EVA LAVIK , MALM ANDERS , MORSING TOMAS , FAGER GUNNAR
Published: December 2004

DOTA, C.D., et al.: Inter‐ and Intraday Variability in Major Electrocardiogram Intervals and Amplitudes in Healthy Men and Women.
The ECG may vary during the day (intra‐day), and between days (interday), for the same subject. Variability in ECG characteristic measurements between different investigators is well documented and is often large. During days 1–6 of each placebo period of a two‐way crossover Phase I study, digital ECGs were recorded at about 8 and 12 am in 16 healthy volunteers (8 men, 8 women). Two observers independently analyzed leads V2 and V6 using EClysis software. The durations and amplitudes of major ECG waves and the intervals between major electrocardiographic events were analyzed in a mixed model ANOVA, in which subject, observer, time, and day were treated as random factors. The influence of various corrections for heart rate on the variability of QT intervals was investigated. The difference among subjects explained between 44–81% of the total variability in ECG intervals and amplitudes. Overall, inter‐ and intraday variability was not statistically significant for any variable. The individualized exponential correction of the QT interval for heart rate eliminated the QT interval dependence on the RR interval in all subjects. Changes in T wave morphology and shortening of the QT interval from morning to noon were observed in ten subjects. The interobserver variability was close to zero

(SD < 0.005 ms)

for all variables except the PQ interval (SD 1.4 ms). The various sources of variability in determinations of ECG wave characteristics should be considered in the design of clinical studies. The use of EClysis software for ECG measurements in this study made the results highly observer independent. (PACE 2003; 26[Pt. II]:361–366)
P Wave Analysis Indices in Young Healthy Men: Data from the Digital Electrocardiographic Study in Hellenic Air Force Servicemen (DEHAS)
Authors: GIALAFOS ELIAS J. , DILAVERIS POLYCHRONIS E. , SYNETOS ANDREAS G. , TSOLAKIDIS GEORGE F. , PAPAIOANNOU THEODOROS G. , ANDRIKOPOULOS GEORGE K. , RICHTER DIMITRIS J. , TRIPOSKIADIS FILIPPOS , GIALAFOS JOHN E.
Published: December 2004

GIALAFOS, E.J., et al.: P Wave Analysis Indices in Young Healthy Men. Data from the Digital Electrocardiographic Study in Hellenic Air Force Servicemen (DEHAS).
P wave analysis from the 12‐lead ECG is a recent contribution of noninvasive electrocardiology. P wave analysis indices (maximum and minimum P wave duration, P wave dispersion [Pdis= Pmax− Pmin], adjusted P wave dispersion [APdis= Pdis/√measured leads], summated P wave duration [Psum], standard deviation of P wave duration [Psd], mean P wave duration [Pmean]) can predict atrial arrhythmias. However, the definitions of all these indices are based on few studies. The aim of this analysis was to define normal values of these indices and the examine possible associations between P wave indices and clinical variables. The study included 1,353 healthy men,

24 ± 3

years of age, who answered a questionnaire and underwent a detailed physical examination and a digitized 12‐lead surface ECG. All P wave indices were analyzed by two independent investigators. Mean values of the ECG indices were:

Pmax: 96 ± 11 ms, Pmin: 57 ± 9 ms, Pdis: 38 ± 10 ms, Psum: 924 ± 96 ms, Psd: 12 ± 3,APdis: 11 ± 3 ms, and Pmean: 77 ± 8 ms

. Age was significantly related with

Pmax (r = 0.277, P < 0.01), Pmin (r = 0.255, P < 0.001), Psum (r = 0.074, P < 0.01), and Pmean (r = 0.074, P < 0.01)

. All ECG indices were significantly associated with the R‐R interval, and among each other. This study defined normal indices of wave duration and correlations among them. These markers may play an important predictive role in patients with atrial conduction abnormalities. (PACE 2003; 26[Pt. II]:367–372)
Ventricular Gradient as a Risk Factor in Survivors of Acute Myocardial Infarction
Authors: BATCHVAROV VELISLAV , HNATKOVA KATERINA , GHURAN AZAD , POLONIECKI JAN , CAMM A. JOHN , MALIK MAREK
Published: December 2004

BATCHVAROV, V., et al.: Ventricular Gradient as a Risk Factor in Survivors of Acute Myocardial Infarction.
The total cosine between R and T (TCRT) (angular difference between the spatial QRS and T wave loops) is a technical elaboration of the concept of ventricular gradient (VG), whose power as a risk stratifier in post‐MI patients has already been demonstrated. Recently, it was reported that TCRT differed significantly between healthy men and women, which suggested that its predictive power might be gender dependent. The aim of the study was to investigate TCRT and its association with cardiac mortality in male and female survivors of acute MI. TCRT was measured from digital Frank orthogonal XYZ‐lead ECGs recorded before hospital discharge in 681 survivors of acute MI (82% men, age: men

57.0 ± 8.4 years

, women

59.6 ± 8.1 years, P = 0.002

). During a follow‐up censored at 5 years, cardiac mortality rates were 9.7% and 12.1% in men and women, respectively

(P = 0.42)

. There were no significant difference in TCRT between men and women (
−0.150 ± 0.704
vs

−0.070 ± 0.731, P = 0.26

). In univariate Cox regression analysis, TCRT

< −0.88

was related to a 5‐year cardiac mortality in men (relative risk [RR] 3.67, 95% confidence interval [CI]

2.13–6.34, P = 1.9 × 10 −6

), and women

(RR 5.16, 95% CI 1.83–14.56, P = 0.0015)

. Depressed TCRT was strongly associated with increased long‐term cardiac mortality in survivors of acute MI. Its predictive power did not differ significantly between the sexes. The role of TCRT as a risk‐stratifier in post‐MI patients deserves further prospective assessment in multivariate models with established risk factors. (PACE 2003; 26[Pt. II]:373–376)
Circadian Rhythm of the Corrected QT Interval: Impact of Different Heart Rate Correction Models
Authors: SMETANA PETER , BATCHVAROV VELISLAV , HNATKOVA KATERINA , CAMM A. JOHN , MALIK MAREK
Published: December 2004

SMETANA, P., et al.: Circadian Rhythm of the Corrected QT Interval: Impact of Different Heart Rate Correction Models. A reduced circadian pattern in the QTc interval has been repeatedly reported to provide prognostic information in cardiac patients. However, the results of studies in healthy subjects in which different heart rate correction formulas were used are inconsistent regarding the presence and extent of diurnal variations in QTc. This study compared the diurnal variations in QTc obtained with four frequently used heart rate correction models with those based on individually optimized heart rate correction. In 53 subjects (25 men aged 27 ± 7 years and 28 women aged 27 ± 9 years) 12‐lead digital ECGs were obtained every 30 seconds during 24 hours. The QT interval was measured automatically by six different algorithms provided by a commercially available device. The QT/RR relation was estimated by four common heart rate correction models and by an individually optimized correction model, QTc = QT/RRα. In each 24‐hour recording, RR, QT, and QTc intervals of separate ECG samples were averaged over 10‐minute intervals. Marked differences were found in the extent of the circadian pattern of QTc obtained with different formulas for heart rate correction. Under and overcorrection of the QT interval resulted in significant over‐ or underestimation of the circadian pattern. Thus, the extent of circadian variation in QTc depends highly on the heart rate correction formula used. To obtain proper insight regarding diurnal variation in QTc prolongation during pharmacologic therapy and/or to assess higher risk due to impaired autonomic regulation of ventricular repolarization, individualized heart rate correction is necessary. (PACE 2003; 26[Pt. II]:383–386)
Effects of Ischemia on Repolarization in Patients with Single and Multivessel Coronary Disease
Authors: GIEDRIMIENE DALIA , GIRI SATYENDRA , GIEDRIMAS ARNOLDAS , KIERNAN FRANK , KLUGER JEFFREY
Published: December 2004

GIEDRIMIENE, D., et al.: Effects of Ischemia on Repolarization in Patients with Single and Multivessel Coronary Disease. To evaluate if QT dispersion (QTd) may be affected by the number of obstructed coronary arteries (CAs) in patients with acute myocardial infarction (MI) and undergoing angioplasty, and to evaluate if QTd may be affected by ejection function of the heart. The infarct related CA was identified by coronary angiography in 141 patients (97 men, mean age61.6 ± 12.9years) with acute MI undergoing percutaneous angioplasty. Successful reperfusion was defined as TIMI III flow with <20% residual stenosis. QTd, calculated by subtracting the shortest from the longest QT interval on 12‐lead electrocardiograms, was examined immediately before and after angioplasty, at 24 hours, and 3 days after angioplasty. Successful reperfusion was achieved in 98 (69.5%) patients. Prolonged QTd at baseline was found in all patients with ischemia. A trend toward a decrease in QTd was observed immediately after angioplasty and at 24 hours, and a significant decrease at 3 days in patients with successful reperfusion regardless of the number of occluded CAs. There was no change in QTd found in patients with no reperfusion. An increase in QTd was observed in patients with acute ischemia due to single or multivessel disease. (PACE 2003; 26[Pt. II]:390–393)
Heart Rate Turbulence in Chagas Disease
Authors: LUIZ ANTONIO , RIBEIRO P. , SCHMIDT GEORG , SOUSA MARCOS R. , LOMBARDI FEDERICO , GOMES MURILO E.D. , PEREZ AMANDA A. , BARROS MÁRCIO V.L. , MACHADO FERNANDO S. , COSTA ROCHA MANOEL OTÁVIO
Published: December 2004

RIBEIRO, A.L.P., et al.: Heart Rate Turbulence in Chagas Disease.
Heart rate turbulence (HRT) quantifies the biphasic response of the sinus node to ventricular premature complexes (VPCs) and is a powerful electrocardiogram related risk predictor. VPCs are frequent in Chagas disease, a potentially lethal illness, and can hamper the analysis by conventional methods of autonomic heart control. The aim of the study was to examine HRT in patients with Chagas disease. Chagas disease patients and healthy controls (group

0, n = 11

) without other diseases were submitted to a standardized protocol, including electrocardiogram, echocardiography, and 24‐hour Holter monitoring. Chagas disease patients were divided according to their left ventricular systolic function: normal (group

1, n = 103

) and reduced ejection fraction (group

2, n = 23

). Two HRT indices, turbulence onset (TO) and turbulence slope (TS), were calculated and compared among groups after adjustment for covariates like the prevalence of VPCs and the mean heart rate. Chagas disease patients had significantly altered TO (group 1: −0.0186, group 2: −0.0126) and TS (group 1: 10.844, group 2: 7.870) values in comparison with controls (TO − 0.0256, TS 19.829);

P < 0.001

for both comparisons. In conclusion, HRT data may be useful in the electrocardiographic analysis of autonomic heart control in Chagas disease. Its prognostic value remains to be determined. (PACE 2003; 26[Pt. II]:406–410)
Rhythm Discrimination by Rate Branch and QRS Morphology in Dual Chamber Implantable Cardioverter Defibrillators
Authors: BORIANI GIUSEPPE , BIFFI MAURO , DALL'ACQUA ALBERTO , MARTIGNANI CRISTIAN , FRABETTI LORENZO , ZANNOLI ROMANO , BRANZI ANGELO
Published: December 2004

BORIANI, G., et al.: Rhythm Discrimination by Rate Branch and QRS Morphology in Dual Chamber Implantable Cardioverter Defibrillators.
Morphology Discrimination is a discriminator based on QRS morphology analysis that has been recently implemented in dual chamber implantable cardioverter defibrillators (ICDs). Detected events are initially classified according to median atrial and ventricular rates (Rate Branch). Then, a series of discriminators (Morphology Discrimination, Stability, Sudden Onset) analyze the rhythm according to specific criteria and the number of discriminators required for VT diagnosis (i.e., requiring “any” or “all” of the specific discriminators to indicate VT). The discriminating accuracy of the algorithm was evaluated in 645 detections recorded during the follow‐up of 25 patients. The overall specificity for 397 supraventricular arrhythmias was 73.5% (292/397) with the tachycardia diagnosis criteria set to “any” and 90.9% (361/397) with the tachycardia diagnosis criteria set to “all.” Sensitivity for VT was 100% and 98.7% (231/234) with the tachycardia diagnosis criteria set to “any” and “all,” respectively. With the tachycardia diagnosis criteria set to “any,” specificity for atrial fibrillation was 88.6%, for atrial flutter 40.3%, for atrial tachycardia 0%, and for sinus tachycardia 97.0%. With the tachycardia diagnosis criteria set to “all,” specificity for atrial fibrillation was 92.40%, for atrial flutter 93.5%, for atrial tachycardia 54.7%, and for sinus tachycardia 99.0%. The contribution of Morphology Discrimination was crucial to improve the specificity of the Rate Branch algorithm. The implementation of Morphology Discrimination in a dual chamber ICD with Rate Branch rhythm classification allows the attainment of high specificity and high sensitivity for ventricular tachyarrhythmias. (PACE 2003; 26[Pt. II]:466–470)
Determinants of Geographic Variations in Pacemakers and Implantable Cardioverter Defibrillators Implantation Rates
Authors: OVSYSHCHER I. ELI , FURMAN SEYMOUR
Published: December 2004

OVSYSHCHER, I.E., et al.: Determinants of Geographic Variations in Pacemakers and Implantable Cardioverter Defibrillators Implantation Rates.
Despite the established therapeutic efficacy of pacemakers (PMs) and implantable cardioverter defibrillators (ICDs), marked geographic and national variations in their implant rates have been documented. Tabulation of implant rates and identification of variation patterns are of only modest significance as many factors influence geographic variations. This study examined statistical data regarding implant rates and analyzed the determinants behind these variations. The results showed: (1) the implantation rate of PMs and ICDs depends heavily on national economic status and demographics. (2) Economic factors are an important determinant of implant rates, though high rates were observed in countries with modest economic resources and highly educated physicians and populations. (3) Evaluation of PM and ICD implant rates per million of an overall population, unless based on demography, can lead to significant inaccuracy when comparing different regions and countries. Adjustment of implant rates consistent with demographic parameters is required. (4) Evaluation of the implant rate as appropriate, greater or less than expected in a given country can be achieved by calculation of a “reference” implant rate, and then by its comparison with the actual implant rate. Questions remaining after this analysis are: (1) How do variations in PM and ICD implant rate relate to quality of life, morbidity, and survival? (2) Will overall patient outcomes benefit from a greater implant rate, and is a higher implant rate cost‐effective? (3) Should each country attempt to reach a “reference” implant rate, independent of its approach to medicine and level of economic development? These questions can only be answered by prospective randomized trials that allow the development of recommendations based on national needs and resources. (PACE 2003; 26[Pt. II]:474–478)
Transplantation of Autologous Endothelial Cells Induces Angiogenesis
Authors: CHEKANOV VALERI , AKHTAR MASSOD , TCHEKANOV GUENNADY , DANGAS GEORGE , SHEHZAD MUHAMMAD Z. , TIO FERMIN , ADAMIAN MILENA , COLOMBO ANTONIO , ROUBIN GARY , LEON MARTIN B. , MOSES JEFFREY W. , KIPSHIDZE NICHOLAS N.
Published: December 2004

CHEKANOV, V., et al.: Transplantation of Autologous Endothelial Cells Induces Angiogenesis.
This study examined the feasibility and efficacy of autologous endothelial cell (EC) transplantation using a fibrin matrix in the ischemic myocardium of sheep. Four weeks after placing an ameroid constrictor in the circumflex artery of 12 adult sheep, four animals (EC group) were subjected to EC transplantation. In four others (saline [SAL] group) saline with added inactivated cells was injected and four animals served as controls. Eight weeks after treatment the animals were sacrificed to assess histology and ultrastructure. Eight weeks after injection, ventricular function was markedly improved in the EC transplant group, but had deteriorated in the SAL and control groups. Myocardial blood flow was also increased in the EC group. Histology and electron microscopy revealed extensive neovascularization after EC transplantation and improved myocardial appearance. Heterotopic transplantation of EC within a fibrin matrix enhances neovascularization, increases myocardial blood flow, and improves left ventricular function. (PACE 2003; 26[Pt. II]:496–499)
Coronary Sinus Lead Extraction
Authors: FRANK G. , TYERS O. , CLARK JACQUIE , WANG YAN , MILLS PAULINE , BASHIR JAMIL
Published: December 2004

TYERS, G.F.O., et al.: Coronary Sinus Lead Extraction.
Complications are reported more frequently with the implantation of coronary sinus (CS) than other types of leads, and attempts to extract CS leads may also be associated with increased risks. The authors have performed nonthoracotomy lead extraction (LE) since 1981 and maintained a detailed database. By November 2001, 796 leads had been removed from 401 patients. We undertook review of our CS‐LE experience to evaluate prevalence, safety, and efficacy. Of 14 patients referred for CS‐LE, 7 were treated in the last year. In six the lead had been placed in the CS intentionally, and in eight inadvertently. One recent patient treated with biventricular pacing was septic and died before LE was undertaken. In nine men and four women (mean age 66 years) had one each CS lead and a total of 34 LEs (2.6/patient). Four CS leads had been in place for <6 months (mean 1.5 month), whereas nine had been in place for between 6 months and 27 years. Several LE methods were used, from simple traction to the use of intraluminal locking stylets and powered sheaths. Complete removal of all leads was achieved in all patients. CS‐LE required a mean of 13 minutes, including 1.8 minutes of fluoroscopy. There were no serious complications during the procedures, and the mean hospital stay was 4 days. (PACE 2003; 26[Pt. II]:524–526)
The Role of Isoproterenol Testing Following Radiofrequency Catheter Ablation of Accessory Pathways in Children
Authors: LIBERMAN LEONARDO , HORDOF ALLAN J. , FISHBERGER STEVEN B. , PASS ROBERT H.
Published: December 2004

LIBERMAN, L., et al.: The Role of Isoproterenol Testing Following Radiofrequency Catheter Ablation of Accessory Pathways in Children.
Isoproterenol (ISO) testing following radiofrequency catheter ablation (RFCA) of accessory pathways (APs) in children is often performed to assess efficacy. However, its role in postablative testing for this indication has not been previously studied. In view of a recent national shortage of ISO, this study reviewed the results of ISO testing in pediatric patients after acutely successful RFCA to evaluate its role in postablative testing. Seventy patients (median age 13.0 years, range 2.8–24 years) underwent acutely successful RFCA for APs. If AP conduction was not present and tachycardia was not inducible with programmed stimulation 30 minutes following RFCA, repeat testing was performed during continuous infusion ISO. ISO infusion resulted in the induction of arrhythmias in 3 (4%) of 70 patients that required further ablative therapy. None of these patients had inducible arrhythmias or AP conduction during postablative testing without ISO infusion. One patient, with the permanent form of junctional reciprocating tachycardia (PJRT), had persistence of AP conduction requiring further RFCA applications. Two patients had inducible AV nodal reentrant tachycardia (AVNRT) that was treated with slow pathway modification. At a median follow‐up of 7.3 months, two (3%) patients had recurrence of tachycardia. These patients did not have inducible tachycardia, AP conduction, or dual AVN physiology with ISO testing. Although ISO may improve AP conduction in patients with PJRT and uncover AVNRT, these results suggest that ISO testing after an apparently successful AP ablation may not be necessary to confirm acute success. In addition, lack of AP conduction on ISO did not rule out the possibility of medium‐term recurrence. (PACE 2003; 26[Pt. I]:559–561)
Predictors of Positive Head‐Up Tilt Test in Patients with Suspected Neurocardiogenic Syncope or Presyncope
Authors: OH JU HYEON , KIM JUNE SOO , KWON HYUN CHEOL , HONG KYUNG PYO , PARK JEONG‐EUY , SEO JUNG DON , LEE WON RO
Published: December 2004

OH, J.H., et al.: Predictors of Positive Head‐Up Tilt Test in Patients with Suspected Neurocardiogenic Syncope or Presyncope.
Neurocardiogenic syncope is the most common cause of syncope in patients who present in outpatient clinics. Head‐up tilt test (HUT) has been widely used to diagnose neurocardiogenic syncope. However, the HUT does not always produce a positive response in patients with suspected neurocardiogenic syncope. The aim of the present study was to assess the clinical history and characteristics of patients with suspected neurocardiogenic syncope or presyncope who undertook HUT, and to identify prognostic factors of a positive HUT response. During the first phase of HUT, patients were tilted to a 70‐degree angle for 30 minutes. If the first phase produced a negative response, the second phase was subsequently performed involving intravenous isoproterenol administration. Of 711 patients, 423 (59.5%) patients showed a positive HUT response. In contrast to previous studies, this study showed that the vasodepressive type (76.6%) was the most common pattern of positive response, and that the rate of positive response during the first phase was low (7.1%). By multivariate analysis, the occurrence of junctional rhythm was found to be a predictor of an impending positive response in HUT

(P < 0.001)
. The shorter time interval between the last episode and HUT was also a predictor of positive response(P = 0.0015). Younger age(P = 0.0003)and a history of physical injury during a syncopal episode(P = 0.019)were found to be associated with a positive response in the first phase of HUT. (PACE 2003; 26[Pt. I]:593–598)
Noncontact Mapping of Ectopic Atrial Tachycardias:
Authors: SEIDL KARLHEINZ , SCHWACKE HARALD , RAMEKEN MONIKA , DRÖGEMÜLLER AXEL , BEATTY GRAYDON , SENGES JOCHEN
Published: December 2004

SEIDL, K., et al.: Noncontact Mapping of Ectopic Atrial Tachycardias: Different Characteristics of Isopotential Maps and Unipolar Electrogram.
The success rate for catheter ablation of ectopic atrial tachycardia (AT) has been limited by the inherent difficulty in localizing the site of origin within the complex three‐dimensional structures of the atria. The objective of the study was to determine the usefulness of a noncontact mapping system for catheter ablation of AT. Radiofrequency ablation of 25 ATs was performed using a noncontact mapping system. Three different characteristics of isopotential maps and unipolar electrogram morphologies were observed: Group 1: Isopotential maps displayed a narrow, sharp ring of colors around a white, center spot. Unipolar electrograms revealed a Q‐S morphology with a rapid dV/dt. Group 2: Isopotential maps displayed a broad ring of colors with little or no white spot in the center. Unipolar electrograms revealed a low amplitude, broad and smooth Q‐S morphology in front of a second component with a rapid dV/dt. Group 3: Isopotential maps displayed a broad ring of colors. Unipolar electrogams revealed a low amplitude and fractionated waveform followed by endocardial breakthrough with a gradual dV/dt. Radiofrequency catheter ablation was successful in all ATs of groups 1 and 2, and failed in two of three ATs in group 3. The overall success rate was 92%. No severe complications were observed. Noncontact isopotential mapping is helpful to identify and characterize the origin of ectopic AT. Ablation success is associated with the characteristics of isopotential maps and unipolar electrogram morphologies. The overall success rate was 92%. (PACE 2003; 26[Pt. I]:16–25)
Influencing the Heart Rate of Rats with Weak External Mechanical Stimulation
Authors: HSIU H. , JAN M.Y. , LIN WANG Y.Y. , WANG W.K.
Published: December 2004

HSIU, H., et al.: Influencing the Heart Rate of Rats with Weak External Mechanical Stimulation.
The ventricular‐arterial coupling is assumed to minimize the expenditure of cardiac energy. From the conjecture of the resonance theory, the arterial system transmits pressure waves and resonates with the heartbeat, therefore, the arterial system is similar to a mechanical resonator. Theoretically, the heart rate can be paced with weak external mechanical stimulation and corresponding blood pressure changes can be observed. A waterbed was activated to generate 0.5‐mmHg pressure vibrations as a stimulus and the rate was set to deviate 5% from the control heart rate. Among 13 studies on seven rats, the linear regression between X (stimulation frequency − control heart rate) and Y (actual changes of the heart rate) is Y = 0.992X = 0.062 (Hz) with a correlation coefficient of 0.97 (Y = X implies complete steering). The intercorrelation coefficient between the change in mean blood pressure and the heart rate was 0.79. The study showed that this weak mechanical stimulation influences the heart rate, and the blood pressure changes according to the heart rate. Cardiovascular optimization and the resonance theory may explain the way one may regulate the heart rate and the blood pressure of humans noninvasively in the future. (PACE 2003; 26[Pt. I]:36–43)
High Defibrillation Thresholds in Transvenous Biphasic Implantable Defibrillators:
Authors: H. SHUKLA HIMANSHU , C. FLAKER GREG , JAYAM VINOD , ROBERTS DAVID
Published: December 2004

SHUKLA, H.H.,

et al.

: High Defibrillation Thresholds in Transvenous Biphasic Implantable Defibrillators: Clinical Predictors and Prognostic Implications.
The aim of this study was to identify clinical characteristics that distinguish patients with high DFTs and assess the prognostic implication. DFTs testing is a lengthy, potentially painful, and a hazardous process. Little information is available concerning the identification of patients with high DFT who undergo ICD surgery with transvenous leads and biphasic energy. This study analyzed 968 patients from two separate clinical studies who received a Medtronic cardioverter defibrillator from January 1995 through November 1999 and who had DFT testing measured by a binary search protocol. Compared to 865 patients with low defibrillation thresholds (<18 J), the 103 patients with high thresholds (≥18 J) had a lower LVEF

(34 ± 16.7 vs 38.3 ± 16.2%, P = 0.01)
, a worse NYHA functional class (23% Class I, 43% Class II, 29% Class III, 5% Class IV vs. 27% Class I, 55% Class II, 17% Class III, 1% Class IV, P < 0.0001), had bypass surgery less often (10.7 vs 27.5%,P < 0.0001), used amiodarone within the past 6 weeks(42.7 vs 27.2%, P = 0.002), and had a history of ventricular fibrillation more often(44.7 vs 33.1%, P = 0.02). Information concerning the number of shocks delivered was available in 345 (35%) patients; 23 were in the high DFT group and 322 were in the low DFT group. Twelve (52%) of the 23 patients in the high DFT arm received3.6 ± 2.7shocks (median 2.5) and 106 (33%) of the 322 patients with low DFT received4.9 ± 9.5shocks (median 2). After 6 months the mortality rate of patients with high thresholds was 11.7 vs 7.8% in patients with low thresholds(P = 0.118). Using a multivariate logistic regression model the significant predictors of death were older age, higher NYHA class, lower LVEF, amiodarone use, had a presenting arrhythmia of ventricular fibrillation and CHF but not initial high defibrillation thresholds. The study found that (1) 11% of patients have high DFTs, (2) clinical characteristics that identify high defibrillation thresholds are NYHA Class III, IV, low ejection fraction, no previous history of bypass surgery, prior amiodarone use preoperatively, and presenting with ventricular fibrillation, and (3) while high DFTs were associated with a more ill patient population, there was no difference in survival in a 6‐month follow‐up. Patients with a predicted low DFTs may be eligible for abbreviated ICD testing while high risk patients require formal testing. (PACE 2003; 26[Pt. I]:44–48)
Tracheomalacia and bronchomalacia in children: pathophysiology, assessment, treatment and anaesthesia management
Authors: AUSTIN JAMES , ALI TARIQ
Published: December 2004

Tracheomalacia and bronchomalacia are becoming increasingly well recognized. Although pathologically benign conditions, they are responsible for considerable morbidity, occasional mortality and significant difficulties in the operating theatre and intensive care unit. We performed an extensive literature search to identify causal associations, methods of clinical and investigative assessment, treatment modalities and anaesthetic experience with these conditions.
Case report of a 13‐year‐old struck by lightning
Authors: Courtman S.P. , Wilson P.M. , Mok Q.
Published: December 2004

Lightning strikes kill 1000 people per year worldwide. Cardiac arrests resulting from lightning strikes have good survival rates but there is a significant degree of morbidity amongst the survivors. This is the case report of a 13‐year‐old boy who had a cardiac arrest following a direct lightning strike, and his subsequent management.
Propofol anaesthesia and metabolic acidosis in children
Authors: Özlü Onur , Özkara H. Asuman , Eris Senay , Öcal Turgay
Published: December 2004

Background: We aimed to investigate the effect of propofol infusion anaesthesia on acid–base status and liver and myocardial enzyme levels of children during short‐term anaesthesia.

Methods: Thirty‐six children, aged 3–12 years, were randomized into two groups. In group P (n = 18), induction and maintenance were performed with propofol, 3 mg·kg−1 and 20, 15 and 10 mg·kg−1·h−1, respectively. In group H (n = 18) following induction with 5 mg·kg−1 thiopenthal, anaesthesia was maintained with 2–3% halothane. Blood samples were obtained following anaesthesia induction and 30, 60 and 120 min after discontinuation of anaesthesia.

Results: There was no difference in lactate dehydrogenase, myocardial creatininephosphokinase, aspartate aminotransferase, alanine aminotransferase and cholesterol levels between and within the groups. All postoperative triglyceride levels were higher and pH levels were lower in group P than group H (P < 0.05) and there was no difference within the groups.

Conclusions: In these healthy patients, short‐term use of propofol did not result in significant acidaemia, nor alterations in hepatic or myocardial enzyme levels.
Cerebrovascular carbon dioxide reactivity in children anaesthetized with propofol
Authors: Karsli Cengiz , Luginbuehl Igor , Farrar Marc , Bissonnette Bruno
Published: December 2004

Background: Propofol, by virtue of its favourable pharmacokinetic profile, is suitable for maintenance of anaesthesia by continuous infusion during neurosurgical procedures in adults. It is gaining popularity for use in paediatric patients. To determine the effects of propofol on carbon dioxide cerebrovascular reactivity in children, middle cerebral artery blood flow velocity was measured at different levels of endtidal (PECO2) by transcranial Doppler sonography.

Methods: Ten ASA I or II children, aged 1–6 years undergoing elective urological surgery were enrolled. Anaesthesia comprized propofol aimed at producing an estimated steady‐state serum concentration of 3 μg·ml−1and a caudal epidural block. PECO2was adjusted randomly in an increasing or decreasing fashion between 3.3, 5.2 and 7.2 kPa (25, 40 and 55 mmHg) with an exogenous source of CO2while maintaining ventilation parameters constant.

Results: Cerebral blood flow velocity increased as PECO2increased from 3.3 to 5.2 kPa (25–40 mmHg) (P < 0.001) and from 5.2 to 7.2 kPa (40–55 mmHg) (P < 0.001). Mean heart rate and blood pressure did not change significantly.

Conclusions: This study demonstrates that cerebrovascular CO2reactivity is maintained over PECO2values of 3.3, 5.2 and 7.2 kPa (25, 40 and 55 mmHg) in healthy children anaesthetized with propofol.
Effective reduction of anxiety and pain during venous cannulation in children: a comparison of analgesic efficacy conferred by nitrous oxide, EMLA and combination
Authors: Hee Hwan‐Ing , Goy Raymond W. L , Ng Agnes Suah‐Bwee
Published: December 2004

Summary Background: EMLA cream is the current technique of choice to reduce pain during venous cannulation in most paediatric practice. Its use is limited by logistic arrangements and failure to improve cooperation and allay anxiety. Nitrous oxide (N2O) would appear to be an effective alternative. A combination technique may be useful in selected patients.

Methods: One hundred and twenty unpremedicated ASA 1 and 2 day surgery patients, aged 8–15 years were randomized into group 1 (EMLA + air/O2), group 2 (50% N2O/50% O2) and group 3 (EMLA + 50% N2O/50% O2). All patients underwent cannulation on the dorsum of the hand with a 22‐G intravenous catheter. Pain behaviour before cannulation was assessed by an observer with Children's Hospital of Eastern Ontario Pain Scale (CHEOPS). Pain during cannulation was evaluated with CHEOPS by an observer and Visual Analogue Scale (VAS) (0–100 mm) by the patient. Satisfaction score (0–100%) for the experience were reported by the patient. Degree of ease of cannulation, time for cannulation were assessed. Heart rate, oxygen saturation were compared before, during and after cannulation.

Results: The self‐reported VAS for group 3 (10.10 ± 14.99) was significantly lower than group 1 (26.13 ± 27.59) and group 2 (18.35 ± 18.11) (P = 0.003). No significant difference existed between VAS for group 1 and 2. There were also significantly more patients with VAS = 0 in group 3 (23/40) versus group 2 (11/40) versus group 1 (10/40), P = 0.004. The satisfactory score in group 3 (93 ± 9.96) was significantly higher (P = 0.039) than group 1 (81.13 ± 24.61) and group 2 (84 ± 22.02). The increase in CHEOPS from before to during cannulation was significant only in group 1 (P = 0.002). There was no significant difference between frequency of patients with side‐effects, ease of cannulation and time taken for cannulation in the three groups.

Conclusions: EMLA and 50% N2O are equally effective for pain reduction while a combination technique provides superior analgesia and satisfaction. N2O has an advantage over EMLA in reduction of pain related behaviour in older children.
Anaesthetic management for Edward's syndrome
Authors: Courrèges P. , Nieuviarts R. , Lecoutre D.
Published: December 2004

We report the anaesthetic management for a Cohen procedure in a girl with Edward's syndrome (trisomy 18). Information in the literature about anaesthetic management in trisomy 18 patients is poor. The patients are dysmorphic, have severe mental retardation and multiple organ malformations of which congenital heart disease is the most important. Our patient was a 7 year‐old girl, such a survival being exceptional with trisomy 18. Anaesthesia is high risk and pain assessment is difficult. Establishing good relations with the family and appraising the need for surgical procedures are the main other difficulties.
A survey of obstetric complications and pregnancy outcomes in paediatric and nonpaediatric anaesthesiologists
Authors: Gauger Virginia T. , Voepel‐Lewis Terri , Rubin Philip , Kostrzewa Amy , Tait Alan R.
Published: December 2004

Background: Obstetric complications such as spontaneous abortion, preterm labour, preterm delivery, low birth weight and congenital anomalies may be associated with exposure to anaesthetic gases. We hypothesized that female anaesthesiologists practicing primarily paediatric anaesthesia, with increased exposure to trace anaesthetic agents, experience a greater prevalence of obstetric complications than female anaesthesiologists performing primarily adult anaesthesia.

Methods: Questionnaires were sent to all female Society for Pediatric Anesthesia (SPA) members and to an equal number of randomly selected female American Society of Anesthesiologists (ASA) members. Subjects were asked to answer questions regarding their pregnancy outcomes, work history and personal habits. Parametric data were analysed by unpaired t‐tests. Nonparametric data were analysed by chi‐square, Fisher's exact test and Mann–Whitney U‐test as appropriate.

Results: Paediatric anaesthesiologists were defined as those having >75% paediatric practice. Paediatric anaesthesiologists were older and had greater operating room exposure during their pregnancies than nonpaediatric anaesthesiologists. There was a significantly higher prevalence of spontaneous abortion among paediatric anaesthesiologists than nonpaediatric anaesthesiologists. In an exploratory analysis, the following factors were found to be significantly associated with the development of spontaneous abortion: age >35 years, gravida >1, exercise during pregnancy, percentage of inhalational anaesthetics >75% and paediatric anaesthesia practice >75%. Independent risk factors for spontaneous abortion among anaesthesiologists included exercise (>1 time/week) and age.

Conclusion: Our results suggest a higher prevalence of spontaneous abortion in anaesthesiologists whose practice is >75% paediatrics.
The management of a postdural puncture headache in a child
Authors: Liley Andrew , Manoharan M. , Upadhyay V.
Published: December 2004

We present a case of an 11‐year old girl who underwent an elective pyeloplasty and had an epidural catheter placed for per‐ and postoperative analgesia. Postoperatively she developed a postural headache and severe nausea, and a diagnosis of postdural puncture headache (PDPH) was made. Her symptoms failed to respond to conservative management. An epidural blood patch was performed with immediate and complete resolution of her symptoms. We present this case to highlight the occurrence of PDPH in children and to outline the considerations for management.
The correlation between bispectral index and airway reflexes with sevoflurane and halothane anaesthesia
Authors: Davidson Andrew
Published: December 2004

Background:  Unwanted airway reflexes such as laryngospasm are a frequent cause for concern in paediatric anaesthesia. They are more active during light anaesthesia. Bispectral index (BIS) is a recognized measure of anaesthetic effect. Ensuring adequate depth with the BIS may prevent these reflexes. This study investigates the relationship between BIS and a defined measure of airway reactivity.

Methods:  Sixty‐two children scheduled for direct laryngoscopy and bronchoscopy were enrolled in this prospective nonrandomized blinded study. They were induced and maintained with either sevoflurane or halothane. When depth of anaesthesia was judged deep enough on clinical grounds, the cords were sprayed with 2% lidocaine. Using an A2000 monitor, the BIS was recorded at the moment of spraying the cords. The anaesthetist was blinded to the BIS and noted whether or not spraying resulted in complete closure of the cords. Breath holding, desaturation and coughing were also recorded as secondary endpoints.

Results:  Using logistic regression there was a significant correlation between BIS and cord closure for halothane but not for sevoflurane (halothane Pseudo r2 = 0.5, P = 0.003; sevoflurane Pseudo r2 = 0.0004, P = 0.9). Although the study was not specifically designed to test for it, no difference was detected between agents in the incidence of cord closure (halothane 38%, sevoflurane 36%), or secondary endpoints (halothane 29%, sevoflurane 29%).

Conclusions:  The BIS may be useful to help prevent unwanted airway reflexes when using halothane but not with sevoflurane. The differing sites of anaesthetic action for sevoflurane and halothane may explain this result.
Impossible laryngeal intubation in an infant with Fraser syndrome
Authors: Crowe Suzanne , Westbrook Andrew , Bourke Margaret , Lyons Barry , Russell John
Published: December 2004

Congenital webbing of the vocal cords is rare, and is usually incompatible with life. We report a case of an infant with Fraser syndrome who required a surgical airway because of a severe stenosis of her airway secondary to a glottic web. The decision process leading to tracheostomy in this neonate is described. The pertinent features of Fraser syndrome in relation to airway management are discussed.
Usefulness of a New Active‐Fixation Lead in Transvenous Temporary Pacing from the Femoral Approach
Authors: DE COCK CAREL C. , VAN CAMPEN LINDA C.M.C. , VISSER CEES A.
Published: December 2004

DE COCK, C.C., et al.: Usefulness of a New Active‐Fixation Lead in Transvenous Temporary Pacing from the Femoral Approach.
Temporary transvenous pacing is associated with a high incidence of complications with a substantial dislocation rate reported to occur in more than one‐third of patients. This article describes a novel 3.5 Fr temporary pacing lead using active fixation in a consecutive series of 42 patients with prolonged (≥48 hours) temporary pacing. The dislocation rate was 4.8%, while in 7.1% of patients inappropriate pacing (more than a twofold increase of initial pacing threshold) was observed. The total procedural related complication rate (dislocation, inappropriate pacing, local infection, and/or thrombosis) was 31% during a mean duration of pacing of

5.96 ± 2.6 days

. Ambulatory pacing was performed in the vast majority (74%) of patients. Temporary transvenous pacing using an active‐fixation lead is safe and permits long‐term ambulatory pacing with a low dislocation rate.(PACE 2003; 26[Pt. I]:849–852)
Single Chamber Atrial Fibrillation Involving Only the Left Atrium:
Authors: KARCH MARTIN R. , NDREPEPA GJIN , SCHNEIDER MICHAEL A.E. , WEBER STEFAN , SCHREIECK JÜRGEN , SCHMITT CLAUS
Published: December 2004

KARCH, M.R., et al.: Single Chamber Atrial Fibrillation Involving Only the Left Atrium: Implications for Maintenance and Radiofrequency Ablation Therapy.
Due to the anatomic and the functional interatrial relationship, AF is a biatrial process. Whether one of the atria could sustain AF is not known. This study included 11 patients (mean age

± 1

years, 7 men) with AF who showed a distinct activation pattern, characterized by regular activity in the right atrium (RA) and irregular fibrillatory activity confined to the left atrium (LA) throughout the AF episodes. Each of the atria was mapped with 64‐electrode basket catheters. AF was monitored for

74 ± 26 minutes

. Complex and irregular activity with a cycle length of

138 ± 43 ms

was observed in the LA throughout the monitoring time. The posterior and the roof of the LA showed the highest degree of disorganization. RA was activated by regular wavefronts with a cycle length of

194 ± 22 ms

(

P < 0.001

, compared with LA). No fibrillatory activity was observed in the RA. All wavefronts that activated the RA were of septal origin: high anteroseptal 52%, low posteroseptal 22%, mid‐septal 18, and dual wavefronts (from the high anteroseptal and low posteroseptal pathways) 8%. The lateral wall of the RA was activated in a superoinferior direction in 82% of all activations. A left‐to‐right conduction block during AF and a rotor of fibrillatory activity located in the posterior wall of the LA were observed in two patients. Isolated AF in the LA showed various surface electrocardiographic patterns. It is concluded that LA alone without participation of the RA can sustain AF. These data have implications for mechanisms and the ablative therapy of AF. (PACE 2003; 26[Pt. I]:883–891)
Holter Monitoring vs Tilt Testing in the Investigation of Suspected Vasovagal Syncope
Authors: FITCHET ALAN , STIRLING MARLENE , BURNETT GILL , GOODE GRAHAM K. , GARRATT CLIFFORD J. , FITZPATRICK ADAM P.
Published: December 2004

The aim of this study was to compare the diagnostic yield of 48‐hour Holter monitoring with head‐up tilt (HUT) test in patients presenting with blackouts suggestive of vasovagal syncope. One hundred and eighteen consecutive patients, 68 women, aged (mean [SD])50 ± 20  years(range 16–88 years), underwent 48‐hour Holter monitoring and 60° HUT test within 3 months. Endpoints were symptom‐ECG correlation during Holter monitoring and positive HUT test. Syncope occurred in 3 (3%) patients during Holter monitoring, the rhythm being sinus tachycardia in all. Presyncope was reported in 22 (19%), the rhythm being sinus tachycardia in 6, persistent atrial fibrillation in 2, and normal sinus rhythm in the remainder. Asymptomatic arrhythmias were recorded in 103 (87%) patients. Positive HUT tests occurred in 39 (33%), the pattern being mixed (VASIS type 1) in 14 (36%), cardioinhibitory (VASIS type 2) in 3 (8%), and vasodepressor (VASIS type 3) in 22 (56%). Change in patient management occurred in 3 (3%) patients following Holter monitoring and 39 (33%) patients following HUT test. Holter monitoring produces a low yield of clinically useful information in the investigation of suspected vasovagal syncope. An HUT test should be considered the primary investigation of choice in such patients. (PACE 2003; 26[Pt. I]:1523–1527)
Spontaneous Conversion of Permanent Atrial Fibrillation into Stable Sinus Rhythm After 17 Months of Biventricular Pacing
Authors: MALINOWSKI KLAUS
Published: December 2004

A 68‐year‐old woman with drug refractory congestive heart failure (NYHA Class III, ejection fraction 35%, moderate to severe mitral regurgitation) and permanent atrial fibrillation uninterrupted for >3 years, underwent implantation of a biventricular pacing system. Seventeen months later, atrial fibrillation spontaneously converted into sinus rhythm, which has been maintained for more than 6 months (to date). (PACE; 26[Pt. I]:1554–1555)
Atrial Fibrillation in Patients with Congestive Heart Failure
Authors: KNIGHT BRADLEY P.
Published: December 2004

CHF and AF are common problems that are frequently encountered together. These two disease states interact in a way that can result in a viscous cycle. This brief review will attempt to address the interaction between AF and CHF, atrial pathology and abnormal electrophysiology, clinical consequences, prognostic importance, and therapy. (PACE 2003; 26[Pt. II]:1620–1623)
Revelation® Tx Microcatheter Maze Procedure Successfully Treats Paroxysmal AF
Authors: Kocheril A.
Published: December 2004

Introduction: Currently the recommended treatment for atrial fibrillation is pharmacologic therapy. The ability of antiarrhythmic drugs to maintain normal sinus rhythm ranges from 39% to 79% in the first year. A multicenter, prospective clinical study involving 20 centers and 80 subjects has shown promising results for an effective, minimally invasive treatment of paroxysmal AF with a novel RF ablation microcatheter (Cardima®). Methods: Patients with drug refractory, paroxysmal AF were treated with an RF ablation version of the MAZE procedure placing linear lesions in the right atrium. Patients served as their own controls, establishing a baseline episode frequency in the 30 days prior to treatment. Treatment outcomes were compared to baseline to determine treatment effectiveness. Results: Of 79 subjects who reached 6 months follow up by July 2002, 46.8% reported 100% reduction in symptomatic AF episodes and 84.8% reported ≥50% reduction in episode frequency. Subjects also demonstrated clinically significant and statistically significant improvements in quality of life measurements. Conclusion: These results indicate substantial patient benefit from the minimally invasive maze procedure performed with the REVELATION Tx Microcatheter.