bluuebunny/crossref_metadata_2025 huggingface dataset:
Ventricular Arrhythmias Following Thermal Damage of Epicardial Tissue: Possible Causes and Clinical Implications
Authors: WARE DAVID L. , BOOR PAUL , YANG CHUNJIE , GOWDA ASHOK , MOTAMEDI MASSOUD
Published: June 2006

Epicardial heating may be used for ventricular tachycardia (VT) ablation and transmyocardiai revascularization. However, the potential risks of thermal epicardial injury, including arrhythmia, have not been fully explored. This study relates the pathologic and arrhythmic se‐quellae of epicardial heating when applied with a diode laser at varying doses. Acute pathology and dosimetry were determined in a group of normal dogs using 2–3 W over 30–90 seconds. Another group received a similar dose range before undergoing 24‐hour monitoring, and electrophysiological testing was done at 4 weeks. In this group, four dogs each received 12 lesions (90–180 J) according to a randomized block design. Another dog received nine lower dose lesions (30–120 J). Acute lesions measured 2.5–8.0‐mm wide by 4–8.5‐mm deep. Charring and vaporization were common when 3 W were applied over 45 seconds. Within 24 hours. VT with features of abnormal automaticity occurred in all dogs receiving this dose. The dog in whom lower doses induced coagulation only had no VT. Four weeks later, electrophysiological study induced no VT. At this time fibrosis and granulation tissue were organizing the contraction band necrosis seen acutely, and some lesion borders were becoming calcified. No major vessels had been damaged. Abnormal automaticity and VT may occur if thermal damage of the epicardium exceeds coagulation. This could be related to tissue injury caused by sudden water vaporization, and may have clinical relevance given the growing indications for myocardial heating.
T Wave Alternans as a Risk Predictor in Patients with Cardiomyopathy and Mild‐to‐Moderate Heart Failure
Authors: HENNERSDORF MARCUS G. , PERINGS CHRISTIAN , NIEBCH VERENA , VESTER ERNST G. , STRAUER BODO‐E.
Published: June 2006

The analysis oft wave alternans (TWA) was introduced to identify patients with an increased risk of ventricular tachyarrhythmias. The inducibility of ventricular tach‐yarrhythmias and the spontaneous arrhythmic events are correlated with a positive TWA in patients with a reduced left ventricular ejection fraction and survived myocardial infarction. In contrast, this study is the first to investigate the correlation of a survived sudden cardiac death and TWA in patients without coronary heart disease and only slightly decreased left ventricular function. Sixty patients were included in the study. The TWA analysis was performed using the Cambridge Heart system (CH2000). Patients were sitting on a bicycle ergometer and exercised with a gradual increase of workload to maintain a heart rate of at least 105 beats/min. The exercise test was stopped after recording 254 consecutive low noise level heart beats. The electrocardiographic signals were digitally processed using a spectral analysis method. The magnitude of TWA was measured at a frequency of 0.5 cycles/beat. A TWA was defined as positive if the ratio between TWA and noise level was > 3.0 and the amplitude of the TWA was > 1.8 μV. Twelve (20%) of the included 60 patients showed a positive TWA. The sensitivity concerning a previous arrhythmic event amounted to 65%, the specificity up to 98%, respectively. The alternans ratio was significantly higher in patients with a previous event (30.3 ± 53.2 vs 2.9 ± 5.9, P < 0.001) and cumulative alternans voltage (4.67 ± 3.55 vs 1.75 ± 1.88 μV, P < 0.001). In 19 patients, invasively investigated by an electro‐physiological study, a significant correlation between inducibility of tachyarrhythmias and a positive TWA result was found (Spearman R = 0.51, P = 0.01). In conclusion, the TWA analysis seems to identify patients with nonischemic Cardiomyopathy who are at an increased risk of ventricular tachyarrhythmias.
Updated Appraisal of Pacing Lead Performance from the Danish Pacemaker Register: The Reliability of Bipolar Pacing Leads Has Improved
Authors: ARNSBO PER , MØLLER MOGENS ,   on behalf of the danish pacemaker register
Published: June 2006

The Danish Pacemaker Register was established in January 1982, and the 12 implanting centers in Denmark report to the Register on a continuous basis by use of the European Pacemaker Patient Identification Card. As of August 1999, the Register contained data on 33,164 bradycardia, endocardial, and epicardial (n = 159) iead implants performed in Denmark on 27,738 generators in 24,180 patients for a total of 17,988 (54.2%) ventricular unipolar, 5,610 (16.9%) ventricular bipolar, 2,056 (6.2%) atrial unipolar, and 7,242 (21.8%) atrial bipolar leads. Lead failure was defined as need for replacement or surgical abandonment of the lead due to pacing or sensing problems with the exception of lead displacement. The 10‐year survival rate for unipolar leads was 97.2 ± 0.4% (± 2 SE) as compared to 79.6 ± 3.2% for bipolar leads (P < 0.001). The Medtronic 4012, the. Telectronics 284, and the Siemens (Pacesetter) 1010T, 105T. and 1050T bipolar lead models were poor performing leads that needed careful monitoring and appropriate replacement. Excluding those five poor performing bipolar leads, the models yielded a 10‐year survival rate of 94.3 ± 2.4% for bipolar leads. The 5‐year survival for all bipolar leads implanted after January IS, 1993 (this was the date that the last of the five poor performing bipolar lead models were implanted in Denmark) was 98.7 ± 0.4% compared with 98.9 ± 0.3% for all unipolar leads implanted after January 18, 1993 and 86.8 ± 1.6% for all bipolar leads implanted on or before January 18, 1993. These results indicate a significant improvement in bipolar lead reliability.
Cross‐Spectral Analysis of Heart Rate and Blood Pressure Modulations
Authors: WICHTERLE DAN , MELENOVSKY VOJTECH , SIMEK JAN , NECASOVA LUCIE , KAUTZNER JOSEF , MALIK MAREK
Published: June 2006

The cross‐spectral analysis of heart rate (HR) and blood pressure (BP) variabilities provides “amplitude” and “phase” related measures. Compared to the amplitude measure, that is the baroreflex gain, the phase related measure characterizing the time lag between HR and BP oscillations has been studied to a much lesser extent. A population of 103 patients (73 men, 30 women, aged 53 ±12, range 20–82 years) referred for the management of coronary artery disease and/or hypertension were studied. In each subject, electrocardiogram and BP recordings were obtained in the supine and sitting positions of 5 minutes of rest (spontaneous respiration), 3 minutes of controlled respiration at 0.1 Hz (slow‐controlled respiration), and 3 minutes of controlled respiration at 0.33 Hz (fast‐controlled respiration). The frequency of maximum coherence (above the arbitrary threshold of 0.5) of BP and RR interval variabilities was searched between 0.033–0.133 Hz and 0.200–0.400 Hz to obtain baroreflex gain and phase shift in low and high frequency bands, respectively. Mean phase shifts of ‐79.1 and ‐67.0 degrees (‐2.4 and ‐2.1 s) were found during slow‐controlled respiration in the supine and sitting body positions, respectively. The mean phase shift between systolic BP and RR interval in the low frequency band was found between 83 and ‐109 degrees for body positions and respiration regimes. The actual baroreflex related time lag between systolic BP and RR variations was found between 3.5 and 5.1 seconds. The study concludes that the appropriate, and not always easy, selection of the frequency of maximum coherence between BP and HR oscillation is crucial for an accurate cross‐spectral assessment of baroreflex sensitivity.
Potentially Fatal Interaction Between Azithromycin and Disopyramide
Authors: GRANOWITZ ERIC V. , TABOR KENNETH J. , KIRCHHOFFER JAMES B.
Published: June 2006

A patient on disopyramide developed disopyramide toxicity when treated concurrently with azithromycin. Evidence of toxicity included an elevated serum disopyramide level and ventricular tachycardia requiring cardioversion. The azalide antibiotic presumably inhibited dealkylation of disopyramide to its major metabolite, mono‐N‐dealkyldisopyramide. Physicians should avoid using azithromycin in patients on disopvramide. If this drug combination is unavoidable, disopyramide levels must be closely monitored.
Inappropriate Pacing Due to Autoperpetuation of the Ventricular Rate Stabilization Algorithm: A Manifestation of T Wave Oversensing by ICDs
Authors: PINSKI SERGIO L.
Published: June 2006

Preventive pacing algorithms designed to eliminate the pause that follows a premature ventricular depolarization have been incorporated in current implantable defibrillators. We report a patient in whom intermittent T wave oversensing frequently invoked the ventricular rate stabilization algorithm and resulted in periods of inappropriate VVI pacing. The problem was solved by decreasing the maximum sensitivity from 0.3 mV to 0.45 mV. Implant testing had revealed adequate sensing of ventricular fibrillation with a maximum sensitivity of 1.2 mV.
Frequency‐Domain Analysis of Heart Rate Variability During Positive and Negative Head‐Up Tilt Test: Importance of Age
Authors: RUIZ GRACIELA AURORA , MADOERY CRISTIåN , ARNALDO FABIåN , MENÉNDEZ CAROLINA , TENTORI MARIA CRISTINA
Published: June 2006

The study of autonomic behavior during a head‐up tilt test (HUT) has been deemed important to understand the loss of consciousness mechanism. Though HRV in patients with HUT(+) and HUT(‐) has been compared, few trials emphasized the importance of age. HRV in fre‐quency domain was analyzed based on 5‐minute samples in the supine position, and between 5 and 10 minutes during early tilt test (R1) in 102 patients with one or more episodes of syncope (mean age 44.3 ± 20.8, range 15‐85 years, 55 women). Two subgroups were selected afterwards: (1) young patients between 15 and 35 years of age (41 patients) and (2) elderly patients aged 60 or more (36 patients). The following parameters were taken into account: the sum of low (LF) and high frequency (HF) (LF and HF in absolute values and in normalized units), the LF/HF ratio (L/H ratio), and the percentage of change between base line and Hi values. The HRV behavior in young and elderly patients with positive and negative HUT was established. We then analyzed the correlation between HRV and age and HUT outcome. A multiple re gression analysis encompassing age, HUT outcome, gender, and number of syncope episodes was per formed. In young patients, the LF and HF areas and the L/H ratio changed significantly between baseline and Rl. The L/H ratio increases from baseline to Rl. Conversely, these differences were not significant in the elderly. No differences between HUT(+) and HUT(‐) within the same age group were observed. Age related significantly to practically ail HRV parameters analyzed, whereas the tilt test outcome correlates poorly with HF normalized units and LF normalized units during Rl, and the L/H ratio changes between baseline and Rl. By means of a multivariate analysis, only age shows a significant correlation with the HRV values. Despite an all age triggering of vasovagal syncope during HUT, the young and elderly pa tients’autonomic behavior differs. The young considerably increase their sympathovagal balance during HUT, whereas the elderly have a mitigated autonomic response. No significant differences were observed during the first minutes of the test between those with a HUT(+) and those with a HUT(‐) within the same age group. Age, and not the HUT response, is the major determinant of the autonomic behavior during early HUT.
Study of Interactions Between Permanent Pacemakers and Electronic Antitheft Surveillance Systems
Authors: MUGICA JACQUES , HENRY LAURE , PODEUR HERVÉ
Published: June 2006

Interference of electronic antitheft systems (EASs) with pacemakers has been an object of controversy. This study was performed in 204 patients followed by our pacemaker surveillance center. The data from a total of 408‐patient exposures to the EAS were analyzed. The device tested con‐sisted of 129 DDD, 71 VVI, and 4 VDD pacemakers from seven manufacturers. The EAS studied consisted of an “acoustomagnetic” system that emits an intermittent 58‐kHz signal, and a magnetic audio frequency system that emits a continuous 73‐Hz signal. Complete interrogation of the pacemakers was performed be fore and after the consecutive exposure of the patients to both EASs. Electrocardiograms were recorded while the patients were exposed to the magnetic fields of each EAS for up to 30 seconds. One or more EAS interferences occurred in 17% of patients. EAS was observed in 26 (20%) of 729 patients with ODD, 7 (10%) of 71 patients with VVI, and 2 (50%) of 4 patients with VDD pacemakers. Over twice as many in stances of EAS interference were observed with the “acoustomagnetic” system as were with the magnetic audio frequency system. Among pacemakers programmed in the ODD mode, a considerably greater preva‐lence of interference was observed at the atrial versus ventricular level, despite the same programmed sensing polarity in both chambers in all but one case. Sensing anomalies were the most common EAS in‐duced disturbance, and typically lasted for the duration of exposure. In a few instances of pacing inhibi‐tion, the phenomenon was limited to 1 cycle at the onset of EAS exposure. No changes occurred in the programming of the pacemakers, and a single patient experienced palpitation during EAS induced rapid pacing. During exposure to EAS mimicking the normal use of the systems, interference with a variety of pacemakers was relatively common. However, the anomalies observed were transient and the cause of no symptom or device reprogramming. Patients should be advised to not stand unnecessarilv in the close proximity of EASs.
The Postural Orthostatic Tachycardia Syndrome: A Potentially Treatable Cause of Chronic Fatigue, Exercise Intolerance, and Cognitive Impairment in Adolescents
Authors: KARAS BARRY , GRUBB BLAIR P. , BOEHM KATHY , KIP KATRINKA
Published: June 2006

Head upright tilt table testing has become an accepted method to measure an individual's predisposition to autonomically mediated periods of hypotension and bradycardia severe enough to cause frank syncope. At the same time it has become increasingly apparent that less profound falls in blood pressure, while not sufficient to result in loss of consciousness, may cause symptoms such as near syncope, vertigo, and dizziness. We describe a subgroup of adolescents that have a mild form of autonomic dysfunction that exhibit disabling symptoms such as postural tachycardia and palpitations, extreme fatigue, lightheadedness, exercise intolerance, and cognitive impairment. During baseline tilt table testing at a 70° angle, these patients demonstrated a heart rate increase of ≥30 beats/min (or a maximum heart rate of ≥120 beats/min) within the first 10 minutes upright (not associated with profound hypotension), which reproduced their clinical symptom complex. Similar observations have been made in the adult population and has been termed the postural orthostatic tachycardia syndrome (POTS). We report that POTS may also occur in adolescents and represents a mild, potentially treatable form of autonomic dysfunction that can be readily identified during head upright tilt table testing.
Clinical and Electrocardiographic Predictors of Recurrent Atrial Fibrillation
Authors: DILAVERIS POLYCHRONIS E. , GIALAFOS ELIAS J. , ANDRIKOPOULOS GEORGE K. , RICHTER DIMITRIS J. , PAPANIKOLAOU VASILIOS , PORALIS KONSTANTINOS , GIALAFOS JOHN E.
Published: June 2006

Patients with frequent episodes of paroxysmal atrial fibrillation (AF) are prone to develop permanent AF and have an increased thromboembolic risk. We have previously shown that P wave dispersion (P dispersion), defined as the difference between the maximum and the minimum P wave duration, and maximum P wave duration (P maximum) can distinguish patients with paroxysmal lone AF. The ability of those ECG markers and of other clinical and ECG variables to detect patients at risk for recurrent AF was tested in 88 patients, aged 64 ± 12 years. All patients had a history of symptomatic episodes of AF during the last 2 years and had not previously received any antiarrhythmic prophylaxis. P maximum and P dispersion were calculated from a 12‐lead surface ECG recorded in all patients during sinus rhythm. A computerized ECG system was used and P maximum and P dispersion were calculated on screen from the averaged complexes of all 12 leads. Age (P=0.01), history of organic heart disease (P = 0.03), P maximum (P < 0.001), minimum P wave duration (P = 0.05), and P dispersion (P < 0.001) were found to be significant univariate predictors of recurrent AF, whereas only P maximum (P < 0.001) and age (P = 0.037) remained significant independent predictors of frequent AF paroxysms in the multivariatfi analysis. It is concluded that advanced age and prolonged P wave duration may be used as predictors of frequently relapsing AF. Therefore, simple AF predictors exist that could possibly distinguish the patients in whom prophylaxis with antiarrhythmic medicines should be instituted.
QT Dispersion from Body Surface EGG Does Not Reflect the Spatial Dispersion of Ventricular Repolarization in Sheep
Authors: WANG LEXIN
Published: June 2006

The correlation between the QT dispersion on body surface ECG and the dispersion in ventricular repolarization from the cardiac surface was studied in six sheep anesthetized with pentobarbital. The standard 12‐lead body surface ECG and multiple ventricular epicardial ECGs were simultaneously recorded. The activation‐recovery interval (ARI) was measured from the unipolar epicardial ECGs. The pooled QT dispersion from the six animals was significantly smaller than the pooled ARI dispersion (22.7 ± 2.6 vs 33.0 ± 6.9 ms, P < 0.01). There was no correlation between the QT and ARI dispersion. The unipolar epicardial ECGs were then converted into bipolar ECGs and epicardial QT intervals were subsequently acquired from these ECGs. The average value of epicardial QT dispersion from the six animals was similar to that of body surface ECG, but was less than the ARI dispersion (27.5 ± 6.8 vs 33.0 ± 6.9, P < 0.01). A good correlation between the epicardial QT dispersion and ARI dispersion was identified (r = 0.84, P < 0.05). In addition, a prolongation in ventricular repolarization, induced by an increase in coronary flow, elicited a pooled ARI dispersion of 62.3 ± 6.2 ms (n = 6), which was larger than the simultaneously recorded body surface QT dispersion (28.3 ± 9.8 ms, n = 6, P < 0.01). No correlation between the ARI and QT dispersion was found in the presence of the prolonged ventricular repolarization. In conclusion, QT dispersion from a 12‐lead body surface ECG seems to underestimate the spatial dispersion of ventricular repolarization acquired from sheep epicardium.
Preliminary Results with the Simultaneous Use of Implantable Cardioverter Defibrillators and Permanent Biventricular Pacemakers: Implications for Device Interaction and Development
Authors: WALKER S. , LEVY T. , REX S. , BRANT S. , PAUL V.
Published: June 2006

We report our preliminary experience with the combined use of implantable cardioverter defibrillutors (ICD) and biventricular pacemakers in six patients with heart failure and malignant ventricular arrhythmia. Two patients underwent ICD implantation for malignant ventricular arrhythmia after previous biventricular pacemaker implantation. One patient underwent biventricular pacemaker insertion for NYHA Class III heart failure after previous ICD implantation. Two patients underwent single device implantation. In the sixth patient, a combined implantation failed due to an inability to obtain a satisfactory left ventricular pacemaker lead position. The potential for device interaction was explored during implantation. In two patients a potentially serious interaction was discovered. Subsequent alterations in device configuration and programming prevented these interactions with long‐term use. No complication of combined device use has been demonstrated during a mean follow‐up of 2 months (range 1‐4 months). Satisfactory ICD and pacemaker function has also been demonstrated. We conclude that combined device implantation may be feasible with currently available pacing technology and that further prospective studies are required in this area.
Prevention of the Initiation of Atrial Fibrillation: Mechanism and Efficacy of Different Atrial Pacing Modes
Authors: YU WEN‐CHUNG , TSAI CHIN‐FENG , HSIEH MING‐HSIUNG , CHEN CHIEN‐CHENG , TAI CHING‐TAI , DING YU‐AN , CHANG MAU‐SONG , CHEN SHIH‐ANN
Published: June 2006

Several atrial pacing modes have been reported to be effective in the prevention of atrial fibrillation (AF); they included biatrial pacing, dual site right atrial pacing, Bachmann's bundle (BB) pacing, and coronary sinus pacing. However, the relative efficacy and electrophysiological mechanisms of these pacing modes in the prevention of AF are not clear. In 15 patients (age 54 ± 14 years) with paroxysmal AF, P wave duration, effective refractory period, and atrial conduction time were determined with six different atrial drive pacings, that were right atrial appendage (RAA), BB, right posterior interatrial septum (RPS), distal coronary sinus (DCS), RAA plus RPS simultaneously (DSA), and RAA plus DCS simultaneously (BiA). All these patients consistently had AF induced with early RAA extrastimulation coupling to RAA drive pacing. No patient had AF induced with RAA extrastimulation coupled to BB, RPS, or DCS drive pacing, but seven and eight patients had AF induced with RAA extrastimulation coupled to DSA and BiA drive pacing, respectively. The P wave duration was longest during RAA pacing, and became shorter during other atrial pacing modes. Analysis of electrophysiological change showed that early RAA extrastimulation coupled to RAA drive pacing caused the longest atrial conduction delay among these atrial pacing modes; BB, RPS, and DCS drive pacing caused a greater reduction of this conduction delay than DSA and BiA drive pacing. In addition, the effective refractory periods of RAA determined with BB, RPS, and DCS drive pacing were similar and longer than that determined with DSA and BiA drive pacing. In patients with paroxysmal AF, this arrhythmia was readily induced with RAA extrastimuli coupled to RAA drive pacing. BB, RPS, and DCS pacing were similar and more effective than DSA and BiA pacing in preventing AF.
Reduced Frequency of Retention Wire Fractures Suggests That Elective Explantation of Affected Atrial Leads Is No Longer Indicated
Authors: PARSONNET VICTOR , ROELKE MARC , BERNSTEIN ALAN D. , STERN MARTIN
Published: June 2006

Since 1994, 611 patients with atrial Accufix leads have been followed. Consideration was given to explanting these leads based on the presence or absence of fractures of the retention wire. All leads were followed according to a protocol proposed by the manufacturer, chiefly by regular 6‐month high quality X rays and fluoroscopic evaluation. The impact of various conditions on the incidence of fracture was evaluated, such as the shape and location of the lead, prior open heart surgery, and the implantation route. The only factor related to the frequency of fractures was the shape of the lead, fractures occurring statistically more frequently if the leads were pulled from their normal J shape into an L or straightened configuration. The frequency of fractures has plateaued at 6 through 9 years with no further occurrence of Class III or IV fractures (protrusion of the fractured segment). Altogether there were nine (1.5%) Class III and Class IV fractures at the 9‐year follow‐up. Actuarial survival, in Class I or II, was 97%. We concluded, that the frequency of retention wire fractures has plateaued. This information coupled with the knowledge that the Accufix lead extraction can be difficult and dangerous, suggests that the remaining leads are best left in place.
In Vivo Potentiostatic Studies at the Electrode Tissue Interface: Filter Properties of the Monophasic Action Potential (Ag/AgCl) Electrode in Living Rat Heart
Authors: CHOU HOWARD A. , OVADIA MARC , MOSKOWITZ MICHAEL , ZAVITZ DANIEL H.
Published: June 2006

The monophasic action potential (Franz) catheter is regarded as the criterion standard for high fidelity recording of a class of physiological signals. However, its signal modulation characteristics have never been reported. Broadband impedance spectroscopy was performed in perfused living rat heart in a three‐electrode potentiostatic configuration to determine the filtering characteristics of the MAP and model Ag/AgCl electrode‐tissue interfaces. The filter transfer function H(f) (attenuation [dB] vs log(f) [log(Hz)]) was derived for the frequency range 10 Hz‐106 Hz. As a filter, the MAP interface is characterized by two ranges of filtering behavior. At high frequency the MAP interface is a high‐pass filter with passband frequency 54 kHz‐549 kHz (median 321 kHz) and with —3 dB cutoff points ranging from 10 kHz to 302 kHz. In this high frequency range the transfer function is characterized by decreasing attenuation per decade. However, in the lower frequency range relevant to physiological signals (the monophasic action potential, 0.1‐40 Hz), it is a severely attenuating nondiodic high‐pass filter element with an average attenuation of 16.87 dB relative to passband. In this physiological range, rolloff is nonlinear with increasing attenuation per decade. While the MAP electrode and model Ag/AgCl electrodes are high‐pass filters with robust transfer functions for high frequency signals in the living heart, the attenuation of signals in a frequency range relevant to in vivo physiological recording imparts extreme attenuation that may distort physiological signals unpredictably. This disadvantage may be mitigated by amplitude scaling to a calibrated pure tone signal within the physiological frequency band to recover a reproducible signal.
Brugada Syndrome Characterized by the Appearance of J Waves
Authors: DAIMON MASAO , INAGAKI MASAYUKI , MOROOKA SHIGERU , FUKUZAWA SHIGERU , SUGIOKA JUJI , KUSHIDA SHUNICHI , TATENO KAORU , OZAWA SHUN
Published: June 2006

We describe a patient with Brugada syndrome. The ST‐segment elevation in precordial leads was revealed during admission, but the appearance of J waves was characteristic before ventricular fibrillation (VF), rather than ST‐segment elevation. J waves have been reported to be associated with the presence of an Ito‐mediated prominent action potential notch in the epicardium. It is considered that one of the mechanisms of this VF is due to heterogeneous distribution of the refractory period according to changes in K+ channels including Ito. Brugada syndrome, idiopathic VF, J wave, current Ito
Near Fatal Electrical Storm in a Patient Equipped with an Implantable Cardioverter Defibrillator for Brugada Syndrome
Authors: CHALVIDAN THIERRY , DEHARO JEAN‐CLAUDE , DIEUZAIDE PIERRE , DEEAYE PASCAL , DJIANE PIERRE
Published: June 2006

A patient with Brugada syndrome experienced incessant ventricular fibrillation 7 years after implantation of an ICD. Ceneral anesthesia, fast ventricuiar pacing bretylium, and atenolol infusion were ineffective; amiodarone infusion was started. After 190 defibrillation shocks over 36 hours, the electrical storm stopped. A multiorgan failure occurred as a complication of the electrical storm and necessitated prolonged reanimation. Thorough cardiac evaluation revealed no structural abnormality and the patient, now on chronic oral amiodarone therapy, remains free of arrhythmia 1 year after the event
ST Segment and T Wave Alternans in a Patient with Brugada Syndrome
Authors: TADA HIROSHI , NOGAMI AKIHIKO , SHIMIZU WATARU , NAITO SHIGETO , NAKATSUGAWA MASATOSHI , OSHIMA SHIGERU , TANIGUGHI KOIGHI
Published: June 2006

We describe a patient with Brugada syndrome in whom J point and ST‐segment elevation in leads V1 and V2 were augmented by atrial pacing and intravenous administration of propranolol or cibenzoline. Significant T wave alternans with a 2:1 appearance of terminal negative T wave was observed in the absence and presence of atrial pacing after the administration of cibenzoline. The cellular mechanism responsible for T wave alternans. beat‐to‐beat appearance of terminal negative T wave and augmented J point and ST‐segment elevation is discussed
Unmasking Effect of Propafenone on the Concealed Form of the Brugada Phenomenon
Authors: MATANA ANTE , GOLDNER VLADIMIR , STANIĆ KARLO , MAVRIĆ ÅKO , ZAPUTOVIĆ LUKA , MATANA ZRINKA
Published: June 2006

A case report of a patient with frequent ventricular premature beats but with an otherwise normal ECG and no structural heart disease. Propafenone in therapeutical doses unmasked the ECG picture of the Brugada phenomenon
The Effect of Angiotensin II Type‐1 Receptor Gene Polymorphisms on Doppler Blood Flow Parameters of Carotid and Brachial Arteries in Patients with Myocardial Infarction
Authors: Ozturk Onder , Ozturk Unal , Bilici Aslan
Published: June 2006

Background: Genetic influence on Doppler blood flow parameters of carotid and brachial arteries (BA) is uncertain. We investigated the relationship between the angiotensin II type‐1 receptor (AT1R) gene polymorphism and the blood flow characteristics of common carotid arteries (CCA) and BA by color Doppler ultrasound (CDUS) in patients with a first anterior acute myocardial infarction (AMI). Methods and Results: Sixty‐seven patients (15 women and 52 men), aged 25–77 years, with anterior AMI were studied. The AT1R genotypes were established. Based on the polymorphism of the AT1R, they were classified into three groups: AT1R AA genotype (Group1, n = 42 patients), AT1R AC genotype (Group 2, n = 17 patients), and AT1R CC genotype (Group 3, n = 8 patients). Peak‐systolic velocity (PSV) and end‐diastolic velocity (EDV) of right and left CCA, PSV of right BA, and intimal‐medial thickness (IMT) of both CCA were measured by CDUS. All results evaluated statistically. The AT1R genotypes were distributed as follows: 63% AA, 25% AC, and 12% CC. PSV of BA and both CCA were higher in patients with CC and AC than AA (P < 0.05). Also, IMT of both CCA were also higher in the same groups (P < 0.05). Conclusions: Our results suggest that AT1R gene polymorphism influences Doppler blood flow parameters of both BA and CCA, and IMT of CCA. Although further studies are required.
Incremental Prognostic Value of Stress Echocardiography Over Clinical and Stress Electrocardiographic Variables in Patients With Prior Myocardial Infarction: “Warranty Time” of a Normal Stress Echocardiogram
Authors: Bangalore Sripal , Yao Siu‐Sun , Puthumana Jyothy , Chaudhry Farooq A.
Published: June 2006

Background: Patients with prior myocardial infarction (MI) are at increased risk of subsequent cardiac events (MI or cardiac death). The incremental prognostic value and warranty time of a normal stress echocardiogram in this high‐risk population is not well defined. Methods: We evaluated 251 consecutive patients (62 ± 11 years; 64% males) with remote history of MI (>6 weeks) undergoing stress echocardiography (83% dobutamine). Ischemia was defined as a new reversible wall motion abnormality and/or biphasic response. Follow‐up for up to 4 years (mean 2.9 ± 1.0 years) for confirmed MI (n = 7) and cardiac death (n = 15) were obtained. Results: Stress echocardiography effectively risk stratified patients into normal versus abnormal subgroups (Event rate 0.8% per year vs 4.2% per year; P = 0.01; RR = 5.6, 95% CI = 1.3–24.7). In patients with a normal stress echocardiogram, the event rate at the end of 6, 12, and 18 months were <1% per year. After 18 months the event rate in patients with a normal stress echocardiogram increased greatly (>1% per year). Stress echocardiography yields incremental prognostic value over clinical and stress electrocardiographic variables (Global chi‐square increased from 12.4 to 25 to 31.1, P < 0.0001 both groups). Conclusions: Stress echocardiography yields appropriate risk stratification and prognosis and provides incremental prognostic value over clinical and stress electrocardiographic variables even in patients with prior MI. A normal stress echocardiogram portends a benign prognosis (<1% event rate/year) for up to 18 months.
Transient Left Ventricular “Hypertrophy” in a Woman with Meningoencephalitis
Authors: Maeder Micha , Wolber Thomas , Rickli Hans , Ammann Peter
Published: June 2006

We report the echocardiographic findings in a 27‐year‐old woman with viral meningoencephalitis and a positive test for cardiac troponin. Initially, the basal parts of the left ventricle were severely hypokinetic, whereas contraction in the mid‐ventricle and apex was normal. A second echocardiogram obtained 19 days after the development of pulmonary edema showed a generalized, severe myocardial thickening, the left ventricular ejection fraction being normal. Three months after the initial examination the “hypertrophy” had disappeared. The serial echocardiograms along with a positive cardiac troponin led to the diagnosis of myocarditis, which can very rarely present with the echocardiographic picture of severe left ventricular thickening.
Atrial Dissection‐Like Appearance Caused by Ileus Due to Metastatic Renal Cell Carcinoma
Authors: Dogan Mehmet , Ozeke Ozcan , Aras Dursun , Deveci Bulent , Yildiz Ali
Published: June 2006

Atrial dissection is an uncommon entity, defined as a gap from the mitral or tricuspid annular area to the interatrial septum or atrial wall, creating a new chamber with or without communication into the true left or right atrium. We present the interesting images of an atrial dissection‐like appearance in the right atrium, which was actually caused by an ileus due to metastatic renal cell carcinoma in a 82‐year‐old man. The causes of true atrial dissection were also briefly discussed.
Protocol for Optimal Detection and Exclusion of a Patent Foramen Ovale Using Transthoracic Echocardiography with Agitated Saline Microbubbles
Authors: Attaran Robert R. , Ata Imran , Kudithipudi Vijayasree , Foster Laura , Sorrell Vincent L.
Published: June 2006

Agitated saline bubble studies in conjunction with echocardiography, in particular transesophageal echocardiography, are currently the principal means in the diagnosis of patent foramen ovale (PFO). We describe techniques and guidelines for the detection and exclusion of a PFO. The potential for misinterpretation of these bubble studies exists and therefore, several false positive and false negative scenarios are illustrated and discussed.
Role of Contrast‐Enhanced Dobutamine Stress Echocardiography in Predicting Outcome in Patients with Known or Suspected Coronary Artery Disease
Authors: Wake Ryotaro , Takeuchi Masaaki , Yoshitani Hidetoshi , Miyazaki Chinami , Otani Shinichiro , Yoshiyama Minoru , Yoshikawa Junichi
Published: June 2006

Although the application of intravenous contrast agents during stress echocardiography has been shown to improve diagnostic accuracy for detecting coronary artery disease, less information exists regarding its prognostic value. The aim of this study was to determine the role of contrast‐enhanced dobutamine stress echocardiography (DSE) for predicting future cardiac events in patients with coronary artery disease (CAD). We studied 893 patients (mean age: 66, 581 men) with known or suspected CAD undergoing contrast‐enhanced DSE. Positivity was defined as new/worsened wall motion abnormality or fixed abnormality during stress. All patients were followed for 15 ± 10 months to evaluate hard cardiac events (cardiac death and nonfatal myocardial infarction) and total cardiac events (hard cardiac events, congestive heart failure, unstable angina, and late revascularization). Three patients were lost to follow‐up, and 128 patients developed cardiac events, including 21 hard cardiac events. The 3‐year event free survival rate was significantly lower in patients with positive DSE results than in those with negative DSE results. Stepwise Cox multivariate analysis revealed that positivity of DSE (P < 0.0001, Hazard ratio (HR): 2.48) and peak wall motion score index (WMSI) >1.5 (P < 0.0001, HR: 2.41) were independent predictors for total cardiac events. Considering hard cardiac events, the independent predictors were peak WMSI > 1.5 (P < 0.0001, HR: 6.65) and age > 70 years (P < 0.005, HR: 3.27). We conclude that contrast‐enhanced DSE provides important prognostic information for future cardiac events.
Automated Three‐Dimensional Analysis of Mitral Annular Dynamics in Patients with Myocardial Infarction Using Automated Mitral Annular Tracking Method
Authors: Takemoto Yasuhiko , Hozumi Takeshi , Sugioka Kenichi , Watanabe Hiroyuki , Matsumura Yoshiki , Yoshiyama Minoru , Takeuchi Kazuhide , Yoshikawa Junichi
Published: June 2006

Background: A newly developed automated mitral annular tracking method (AMAT) has recently become available and enables us to perform automated analysis of mitral annular dynamics. Purpose: To evaluate mitral annular dynamics using AMAT. Methods: AMAT was performed using a Toshiba Aplio SSA‐770 ultrasound system in 15 normal healthy volunteers (group N), 16 patients with anterior MI (group A), and 12 inferior MI (group B). The distance between an annular point at end‐diastole and at end‐systole (distance D) was automatically measured using AMAT at the basal portion of the anterior, lateral, posterior, inferior, and inferoseptal wall. The angle between the mitral annular plane at end‐diastole and the direction of movement of each mitral annular point from end‐diastole to end‐systole (angle A) was also automatically measured at all five mitral annular points. The coefficients of variation (CV) of both distance D and of angle A were calculated as indices of asynchrony of mitral annular dynamics. Results: CV of distance D in group A (22 ± 9% (P < 0.01 vs group N)) and group B (22 ± 10% (P < 0.01 vs group N)) were both significantly larger than in group N (13 ± 4%). CV of angle A in group A (15 ± 10% (P < 0.05 vs group N)) and group B (15 ± 10% (P < 0.05 vs group N)) were also significantly larger than that in group N (8 ± 3%). Conclusion: Automated analysis using AMAT showed that mitral annular dynamics of patients with MI were less symmetrical than in normal healthy volunteers.
Evaluation of Cardiac Involvement in Hypereosinophilic Syndrome: Complementary Roles of Transthoracic, Transesophageal, and Contrast Echocardiography
Authors: Shah Rajesh , Ananthasubramaniam Karthik
Published: June 2006

Hypereosinophilic syndrome is a rare but important systemic disease with multiple clinical presentations. Approximately 40% of these cases have cardiac involvement. Echocardiography is the most easily available and versatile imaging modality in assessing cardiac involvement in this disease process. As described and reviewed in this case, it may be the first imaging modality to raise suspicion of this disease entity. Hence, clinicians interpreting echocardiograms and caring for patients need to be aware of the manifestations and complementary roles of various echo techniques in delineating cardiac involvement. Furthermore, the importance of a thorough history and laboratory review prior to echocardiography may provide valuable clues which may otherwise be missed.
Thermodynamic Studies of Carbon in Liquid Silicon Using the Central Atoms Model
Authors: Chen Yi , Dhanaraj Govindhan , Dudley Michael , Zhang Hui
Published: June 2006

The activity and solubility of carbon in liquid silicon were calculated using the ideal interstitial solution model. The central atoms model of binary interstitial solution was introduced into the study of carbon solubility in silicon for the first time. The temperature dependence of the carbon activity coefficient and solubility in liquid silicon was presented. Good agreement with the reported data in the literature proves the validity of central atoms model in the thermodynamic studies of a Si–C binary interstitial solution.
Reaction Between Strontium‐Doped Lanthanum Cuprate and Yittria‐Stabilized Zirconia
Authors: Yu Ho‐Chieh , Fung Kuan‐Zong
Published: June 2006

Sr‐doped lanthanum cuprate was recently investigated as a potential cathode material for the intermediate temperature solid oxide fuel cell using yittria‐stabilized zirconia as an electrolyte. The material thermal stability of cathode material against an electrolyte at an operating temperature plays an important role in the fuel cell's performance. In this study, the structural stability between Sr‐doped lanthanum cuprate and 8 mol% yittria‐stabilized zirconia was investigated by using the powder mixture and diffusion couple. The chemical reaction between these two materials in the temperature ranging from 800° to 1000°C was examined by X‐ray diffraction analyses. The interfacial reaction behavior between electrode and electrolyte pellets of the reaction couple was examined by a grazing X‐ray diffractometer, wavelength‐dispersive X‐ray analysis, and an electron probe microanalyzer. No reaction products were observed as these two materials co‐fired at 800°C. The reaction products of pyrochlore La2Zr2O7 and perovskite SrZrO3 were formed when the specimens were heat treated at over 900°C. Because of the formation of these reaction products, the CuO was precipitated. Furthermore, an excess of SrZrO3 formation leads to the phase decomposition of perovskite Sr‐doped lanthanum cuprate to La2−xSrxCuO4 and CuO due to a decrease in strontium concentration in Sr‐doped lanthanum cuprate.
Remission of severely impaired subjective wellbeing in 727 patients with schizophrenia treated with amisulpride
Authors: Lambert M. , Naber D. , Eich F. X. , Schacht M. , Linden M. , Schimmelmann B. G.
Published: June 2006

Objective:  Studies of subjective wellbeing (SW) in schizophrenia have missed to define and to assess rate and predictors of SW response (SW‐res) and SW remission (SW‐rem).

Method:  A total of 727 patients with schizophrenia and severely impaired SW at entry (Subjective Wellbeing under Neuroleptics Scale, short version, SWN‐K, total score ≤60) were treated with amisulpride over 12 weeks. SW‐res was defined as SWN total score increase of at least 20% and by at least 10 points and SW‐rem as total score of ≥80 points.

Results:  Seventy percent fulfilled the SW‐res criterion at week 4. At week 4 and week 12 (endpoint), the SW response criterion distinguished between patients with or without later SW remission and overall symptomatic and functional response. While 39% fulfilled the SW‐rem criterion at endpoint, only 9.1% without early SW‐res were in SW‐rem at follow‐up. Regression analyses indicated that SW‐res was mainly predicted by greater severity of positive symptoms at baseline and SW‐rem by lower severity of negative symptoms and better social functioning, and particularly by early SW‐res.

Conclusion:  Patients with a risk of SW non‐remission need to be identified early with subsequent treatment adaptation according to recommendations for incomplete remission and treatment resistance in schizophrenia.
COX‐1 inhibition enhances scratching behaviour in NC/Nga mice with atopic dermatitis
Authors: Sugimoto Masanori , Arai Iwao , Futaki Nobuko , Hashimoto Yuki , Honma Yusuke , Nakaike Shiro
Published: June 2006

Abstract:  NC/Nga (NC) mice, spontaneously develop an eczematous atopic dermatitis (AD)‐like skin lesion when kept under conventional condition (Conv), but not under specific pathogen‐free (SPF) conditions, have been thought to be an animal model of AD. We have previously shown that PGD2 and arachidonic acid inhibited the scratching behaviour of NC mice, while indomethacin enhanced it. This study was designed to assess the role of cyclooxygenase (COX)‐1 and COX‐2 in the itch‐related scratching behaviour of NC mice. We examined the expression of COX in the skin using real‐time PCR and Western blotting and the effects of SC‐560 (a COX‐1 selective inhibitor) or NS‐398 (a COX‐2 selective inhibitor) on scratching behaviour in relation to skin prostaglandin (PG) levels in NC mice. COX‐1 mRNA expression was unchanged and protein expression decreased in Conv NC mice compared with that of SPF mice. By contrast, COX‐2 mRNA and protein expression increased in Conv NC mice. SC‐560 increased scratching behaviour and significantly reduced skin PGD2, PGE2 and PGF2α levels, but NS‐398 did not have effects on scratching and skin PG level. Moreover, the topical application of PGD2, which might be the endogenous inhibitor of itching, suppressed the SC‐560‐induced enhancement of scratching behaviour by NC mice. These results suggest COX‐1‐coupled skin PGD2 biosynthesis plays a physiological role in inhibiting regulation of pruritus in NC mice with AD.
UVB‐induced interleukin‐18 production is downregulated by tannic acids in human HaCaT keratinocytes
Authors: Park Hyun Jeong , Kim Hee Jung , Kwon Hyun Jo , Lee Jun Young , Cho Baik Kee , Lee Wang Jae , Yang Young , Cho Dae Ho
Published: June 2006

Abstract:  Tannic acids (TAs) are believed to be the key active components in plants, and are believed to be responsible for their anti‐inflammatory, anti‐viral effects and chemoprevention of cancer. However, the molecular mechanisms for the action of TA are unclear. This study examined the effects of TA on cutaneous inflammation with a human keratinocyte cell line (HaCaT). Interleukin‐18 (IL‐18) has multiple effects upon various cells involved in inflammatory response. In this study, the IL‐18 mRNA expression and protein levels were reduced by a TA pretreatment. UV radiation can trigger the induction of the p38 mitogen‐activated protein kinase (MAPK)‐dependent signalling cascade. Immunoprecipitation and Western blot analysis was performed to determine if TA regulate the MAPK signalling pathway. TA significantly inhibited the activation of p38 MAPK and extracellular signal‐regulated protein kinases. Moreover, TA‐inhibited UVB enhanced the expression of the inflammatory mediators, IL‐1, IL‐6, tumor necrotic factor‐α, cyclooxygenase‐2 and prostaglandin E2 in UVB‐irradiated HaCaT cells. The topical application of TA on mouse skin treated with UVB irradiation has shown that TA inhibited the formation of erythema. These findings suggest that TA has significant anti‐inflammatory effects on the UVB‐induced response on the skin and may be a candidate natural compound for the regulation of cutaneous inflammation.
The expression of keratinocyte growth factor receptor (FGFR2‐IIIb) correlates with the high proliferative rate of HaCaT keratinocytes
Authors: Nagy Nikoletta , Bata‐Csörgő Zsuzsanna , Kopasz Norbert , Szeg Csilla , Pivarcsi Andor , Koreck Andrea , Dobozy Attila , Kemény Lajos , Széll Márta
Published: June 2006

Abstract:  Keratinocyte growth factor receptor (KGFR = FGFR2‐IIIb) is a tyrosine kinase receptor expressed by keratinocytes, which mediates the effects of fibroblast growth factors (FGF). There are contradictory data in the literature regarding the role of FGFR2‐IIIb during the proliferation/differentiation programme of keratinocytes. In this study, we aimed to investigate whether overexpression of FGFR2‐IIIb may have a role in the regulation of keratinocyte proliferation. We analysed the expression of FGFR2‐IIIb in an in vitro HaCaT model system representing different stages of proliferation and differentiation of keratinocytes. Real‐time RT‐PCR and Western blot analyses demonstrated a correlation between FGFR2‐IIIb mRNA and protein expression and the proportion of cells in S/G2/M phase in synchronized HaCaT keratinocytes and thus with proliferation activity (r = 0.96). After treatment with the antipsoriatic drug, dithranol, FGFR2‐IIIb is downregulated dose dependently both at mRNA and protein levels. Moreover, when the rate of proliferation is decreased by the lack of cell attachment to the culturing surface, FGFR2‐IIIb mRNA (P = 0.0315) and protein expressions were also reduced (P = 0.0242), while a differentiation marker, keratin 10, mRNA (P = 0.0003) and protein levels (P = 0.001) were increased (r = −0.92). Based on our results we conclude that FGFR2‐IIIb expression in HaCaT keratinocytes corresponds with the proliferative activation of the cells and is not related to the differentiation programme.