bluuebunny/crossref_metadata_2025 huggingface dataset:
Spontaneously Terminating Apparent Ventricular Fibrillation During Transesophageal Electrophysiological Testing in Infants with Wolff‐Parkinson‐White Syndrome
Authors: SANATANI SHUBHAYAN , SAUL J. PHILIP , WALSH EDWARD P. , GROSS GIL J.
Published: July 2003

SANATANI, S., et al.: Spontaneously Terminating Apparent Ventricular Fibrillation During Transesophageal Electrophysiological Testing in Infants with Wolff‐Parkinson‐White Syndrome. This article describes two infants with Wolff‐Parkinson‐White (WPW) syndrome in whom apparent VF occurred without antecedent AF or atrial flutter during routine transesophageal electrophysiological testing. Remarkably, this arrhythmia terminated spontaneously in both infants. The documentation of self‐limited apparent VF, or polymorphic ventricular tachycardia close to VF, in transesophageal testing adds another dimension to the management of WPW.
Pseudotermination of Intermittent Atrial Fibrillation by a Pacemaker Algorithm: Antitachycardia Pacing Without Capture Miscounted as Successful Termination of Fibrillation Episodes
Authors: SCHMITT CLAUS , NDREPEPA GJIN , WEYERBROCK SONJA , KOLB CHRISTOF , ZRENNER BERNHARD
Published: July 2003

SCHMITT, C., et al.: Pseudotermination of Intermittent Atrial Fibrillation by a Pacemaker Algorithm: Antitachycardia Pacing Without Capture Miscounted as Successful Termination of Fibrillation Episodes. A patient is described with intermittent AF and an implanted pacemaker which provides preventive pacing and overdrive stimulation designated to terminate atrial arrhythmias. The case highlights the possibility of false estimation of therapeutic efficacy and possible proarrhythmic effect of this therapeutic modality.
Effect of Restoration of AV Synchrony on Stroke Volume, Exercise Capacity, and Quality‐of‐Life: Can We Predict the Beneficial Effect of a Pacemaker Upgrade?
Authors: PRECH MAREK , GRYGIER M. , MITKOWSKI P. , STANEK K. , SKORUPSKI W. , MOSZYNSKA B. , ZERBE F. , CIEŚLIŃSKI A.
Published: July 2003

PRECH, M., et al.: Effect of Restoration of AV Synchrony on Stroke Volume, Exercise Capacity, and Quality‐of‐Life: Can We Predict the Beneficial Effect of a Pacemaker Upgrade? The aim of this study was to assess to what extent patients with VVIR pacemakers and without overt symptoms of a pacemaker syndrome benefit from a pacemaker upgrade, and if a preoperative noninvasive measurement of the change in stroke volume (SV) could predict the effect of a pacemaker upgrade. The study group consisted of 20 (12 women, 8 men) VVIR patients with a mean age of 60 years. The indication for the first implantation was AV block in 13 patients and SSS in 7. The mean time of a ventricular pacing was 77 months. The objective (echocardiography, an exercise capacity) and the subjective (the quality‐of‐life) parameters investigated in patients during ventricular pacing were compared to results obtained 2 months and 1 year after a pacemaker upgrade. To assess preoperatively a change in a SV expected after upgrading, attempts were made to restore AV synchronization by the use of a transesophageal pacemaker. An increase in SV (from 5% to > 35%) during temporary AV resynchronization was observed in each patient. Values of SV increase correlated with those obtained 2 months (r = 0. 65; P < 0.01) and 1 year (r = 0.66; P < 0.01) after an upgrade. Superior hemodynamics was associated with a significant improvement of an exercise capacity in both subgroups of patients. The most significant improvement in the quality‐of‐life was observed in patients with SSS. We did not find correlations between SV and the quality‐of‐life assessed 2 months (r = 0.043; NS) or 1 year (r = 0.02; NS) after an upgrade. In conclusion, a pacemaker upgrade performed after a long‐term ventricular pacing resulted almost consistently in the improvement of hemodynamics and was associated with an increase of exercise capacity. In patients with SSS it was followed by the significant improvement of their quality‐of‐life. Such a relation was not observed in patients with AV block as some of them (especially those with VVIR pacemakers) felt quite well during ventricular pacing. The proposed preoperative echocardiographic evaluation may precisely predict the degree of hemodynamic improvement expected after a pacemaker upgrade.
Effect of Ventricular Fibrillation Duration on the Defibrillation Threshold in Humans
Authors: GRADAUS RAINER , BODE‐SCHNURBUS LUCAS , WEBER MAX , RÖTKER JÜRGEN , HAMMEL DIETER , BREITHARDT GÜNTER , BÖCKER DIRK
Published: July 2003

GRADAUS, R., et al.: Effect of Ventricular Fibrillation Duration on the Defibrillation Threshold in Humans. Early during ventricular fibrillation, the defibrillation threshold may be low, as ventricular fibrillation most probably arises from a localized area with only a few wavefronts and the effects of global ischemia, ventricular dilatation, and sympathetic discharge have not yet fully developed. The purpose of this study was to explore the effect of the timing of shock delivery in humans. During implantation of an ICD in 26 patients (24 men, 60 ± 11 years, 19 coronary artery disease, NYHA 2.2 ± 0.4, left ventricular ejection fraction 0.42 ± 0.16), the defibrillation threshold was determined after approximately 10 and 2 seconds of ventricular fibrillation. Ventricular fibrillation was induced by T wave shocks. Mean defibrillation threshold was 9.9 ± 3.6 J after 10.3 ± 1.0 seconds. Within 2 seconds, 20 of 26 patients could be successfully defibrillated with ≤ 8 J. In these patients, the mean defibrillation threshold was 4.0 ± 2.1 J after 1.4 ± 0.3 seconds compared to 9.5 ± 3.1 J after 10.2 ± 1.1 seconds (P < 0.001). There were no clinical differences between patients who could be successfully defibrillated within 2 seconds and those patients without successful defibrillation within 2 seconds. In the majority of patients, the defibrillation threshold was significantly lower within the first few cycles of ventricular fibrillation than after 10 seconds of ventricular fibrillation. These results should lead to exploration of earlier shock delivery in implantable devices. This could possibly reduce the incidence of syncope in patients with rapid ventricular tachyarrhythmias and ICDs.
QT Dispersion in 120 Electrocardiographic Leads in Patients with Structural Heart Disease
Authors: STOVICEK PETR , GARDNER MARTIN J. , MITCHELL L. BRENT , BURNS MARK A. , STERNS LAURENCE D. , WARREN JAMES W. , HORACEK B. MILAN
Published: July 2003

STOVICEK, P., et al.: QT Dispersion in 120 Electrocardiographic Leads in Patients with Structural Heart Disease. The clinical significance of QT dispersion (QTd) measured in 12‐lead ECGs is controversial. The aim of this study was to clarify factors that determine the QTd and its measurement errors in different lead arrays in patients with structural heart disease. Two blinded observers measured QT intervals on a computer screen from 120‐channel ECG recordings in a retrospective set of 257 patients, comprising a group of 121 myocardial infarction (MI) survivors without ventricular tachyarrhythmia during a 6‐month followup and a group of 136 survivors of ventricular tachyarrhythmia/fibrillation. QTd did not differ in patients with and without ventricular tachyarrhythmia/fibrillation. Eleven ventricular tachyarrhythmia/fibrillation survivors without structural heart disease had the lowest QTd (P ≤ 0.02). The strongest factor determining QTd and the magnitude of its measurement error was the lead array (P = 0.0001). Measurement errors had two components. The smallest relative errors were in the total body surface mapping array with one component related to interobserver reproducibility (9.1 ± 7.6%), and the other component related to accuracy of measurement of the QT interval (36 ± 16%). The authors estimated that a difference of QTd of at least 50 ms between study groups is required in a 12‐lead ECG to draw any conclusions from the studies. In patients with structural heart disease, QTd from limited arrays of ECG leads was not a reliable measure. It correlated with the presence of structural heart disease, but not with arrhythmogenicity. An array consisting of ECG leads covering the entire chest allowed better reproducibility and measurement accuracy of QTd.
Effect of Electrode Location in Great Cardiac Vein on the Ventricular Defibrillation Threshold
Authors: HUANG JIAN , WALCOTT GREGORY P. , KILLINGSWORTH CHERYL R. , SMITH WILLIAM M. , KENKNIGHT BRUCE H. , IDEKER RAYMOND E.
Published: July 2003

HUANG, J., et al.: Effect of Electrode Location in Great Cardiac Vein on the Ventricular Defibrillation Threshold. This study tested the hypothesis that the DFT could be lowered by delivering a weak auxiliary shock in conjunction with a stronger primary shock with the auxiliary shock electrode near the cardiac region where the primary shock electric field is weakest. This hypothesis was tested by determining the DFTs with the auxiliary shock delivered from different locations within the great cardiac vein (GCV). In 15 dogs, catheters with defibrillation electrodes were placed transvenously in the RV apex, the SVC, and the GCV. An active can electrode and the SVC electrodes were electrically coupled to serve as a return electrode for the RV and GCV electrodes. DFTs were determined for a primary shock through the RV electrode with and without a subsequent auxiliary shock of lower amplitude through the GCV electrode. The leading edge voltage and current at DFT were significantly lowered by addition of the auxiliary shock (17% and 19% decreased, respectively), but energy was not changed. The animals were divided into three groups according to the location of the GCV electrode. The leading edge voltage, current, and total delivered energy at the DFT were significantly lower in animals with the GCV electrode near the apex (22%, 24%, and 13% reduction, respectively) compared with those where the GCV electrode was positioned away from apex (8%, 10% reduction and 18% increase, respectively, P < 0.001). Application of an auxiliary shock to the apical region, near the region where previous studies have indicated that the RV primary shock has its weakest effects, caused the greatest decrease in DFT.
Fluoroscopic Cardiac Anatomy for Catheter Ablation of Tachycardia
Authors: FARRÉ JERÓNIMO , ANDERSON ROBERT H. , CABRERA JOSÉ A. , SÁNCHEZ‐QUINTANA DAMIÁN , RUBIO JOSÉ M. , ROMERO JOSÉ , CABESTRERO FERNANDO
Published: July 2003

FARRÉ, J., et al.: Fluoroscopic Cardiac Anatomy for Catheter Ablation of Tachycardia. The understanding of cardiac anatomy is crucial for the interventional arrhythmologist. In spite of the introduction of several nonfluroscopic navigational tools, some of them capable of reconstructing a computer‐based surrogate of the endocardial surface of the heart cavities, simple fluoroscopy with or without the aid of angiographic techniques is still the most widely used method to guide mapping and ablation procedures. In some instances, fluoroscopic and angiographic methods have no possible replacement to unravel certain arrhythmologically useful anatomic landmarks. New interpretations of cardiac architecture show the need to challenge some traditional anatomic views, like the concept of septums within the heart. The fluoroscopic anatomy also needs to be reconsidered in the light of the new attitudinally oriented nomenclature. This article presents an overview of the fluoroscopic anatomy of the heart. When pertinent, some anatomical concepts are discussed in more detail like the triangle of Koch, the pyramidal space, and the interatrial groove. In the sections on the atria and on the ventricles, the authors focus on the anatomic information that is relevant for mapping and ablation from a fluoroscopic viewpoint, providing some hints on how best to depict the morphological features from the stance of the interventional arrhythmologist. The Visible Human Slice and Surface Server using data sets from the Visible Human Male and Female Project, has been used to facilitate the understanding of the fluoroscopic anatomy.
Inappropriate Mode Switching in a Dual Chamber Pacemaker Due to Oversensing of a High Frequency Signal from a Conductor/Ring Discontinuity (Loose Set Screw)
Authors: KURUVILLA CHERIPARAMBIL , VOIGT LOUIS , KACHMAR KENNETH , REDDY C.V.R. , KASSOTIS JOHN
Published: July 2003

KURUVILLA, C., et al.: Inappropriate Mode Switching in a Dual Chamber Pacemaker Due to Oversensing of a High Frequency Signal from a Conductor/Ring Discontinuity (Loose Set Screw). Two unusual cases are reported of pacemaker oversensing of the impedance pulse by the atrial channel attributed to a loose set screw.
Radiofrequency Catheter Ablation of a Right Free‐Wall Accessory Pathway in Dextrocardia with Complete Situs Inversus
Authors: HERREROS BENITO , EXPÓSITO CARMEN , MESTRE ANTONIA , BETHENCOURT ARMANDO
Published: July 2003

HERREROS, B., et al.: Radiofrequency Catheter Ablation of a Right Free‐Wall Accessory Pathway in Dextrocardia with Complete Situs Inversus. An uncommon case of orthodromic atrioventricular reentrant tachycardia in a patient with dextrocardia and complete situs inversus is reported. There was no associated cardiac abnormality apart from the mirror image dextrocardia. An electrophysiological study and successful catheter ablation of a right free‐wall concealed accessory pathway was performed. A simplified three‐catheter technique from a femoral approach and monoplane fluoroscopy were used in a noncomplicated procedure of normal duration.
Neurocardiogenic Syncope Due to Recurrent Tonsillar Carcinoma: Successful Treatment by Dual Chamber Cardiac Pacing with Rate Hysteresis
Authors: YUE ARTHUR M. , THOMAS RODERIC D.
Published: July 2003

YUE, A.M., et al.: Neurocardiogenic Syncope Due to Recurrent Tonsillar Carcinoma: Successful Treatment by Dual Chamber Cardiac Pacing with Rate Hysteresis. A patient with recurrent tonsillar carcinoma in his neck presented with cardioinhibitory neurocardiogenic syncope. Ventricular demand pacing was ineffective in preventing recurrent symptoms. The pacemaker was upgraded to a dual chamber device with hysteresis that eliminated further syncopal episodes.
Conduction Properties of the Crista Terminalis and Its Influence on the Right Atrial Activation Sequence in Patients with Typical Atrial Flutter
Authors: YAMABE HIROSHIGE , MISUMI IKUO , FUKUSHIMA HIRONOBU , UENO KAZUHIRO , KIMURA YOSHIHIRO , HOKAMURA YOUICHI
Published: July 2003

YAMABE, H., et al.: Conduction Properties of the Crista Terminalis and Its Influence on the Right Atrial Activation Sequence in Patients with Typical Atrial Flutter. The conduction properties of the crista terminalis (CT) and its influence on the right atrial activation sequence were analyzed in 14 patients with typical atrial flutter (AF). Atrial mapping was performed with 35 points of the right atrium during typical AF and during atrial pacing performed after linear ablation of inferior vena cava‐tricuspid annulus (IVCTA) isthmus. Atrial pacing was delivered from the septal isthmus at cycle lengths of 600 ms and the tachycardia cycle length (TCL). The right atrial activation sequence and the conduction interval (CI) from the septal to lateral portion of the IVC‐TA isthmus were analyzed. During AF, the conduction block line (CBL) (detected by the appearance of double potentials along the CT and craniocaudal activation on the side anterior to CT) was observed along the CT in all patients. The TCL and CI during AF were 254 ± 19 and 207 ± 14 ms, respectively. During pacing at a cycle length of 600 ms, the CBL was observed along the CT in four patients, however, a short‐circuiting activation across the CT was observed in the remaining ten patients. The CI during pacing at 600 ms was 134 ± 38 ms, shorter than that during AF (P < .0001). During pacing at the TCL, the CBL was observed along the CT in all patients. The presence of the CBL along the CT prevented a short‐circuiting activation across the CT and resulted in the same right atrial activation as observed during AF. With the formation of the CBL, the CI significantly increased to 206 ± 17 ms and was not different from that during AF. These data suggest that the conduction block along the CT is functional. It was presumed that presence of conduction block at the CT has some relevance to the initiation of typical AF though it was not confirmed.
How to Test Mode Switching in Pacemakers Implanted in Patients: The MOST Study
Authors: PADELETTI LUIGI , GASPARINI MAURIZIO , PORCIANI MARIA CRISTINA , PIERAGNOLI PAOLO , COLELLA ANDREA , MICHELUCCI ANTONIO , PROCLEMER ALESSANDRO , TOGNARINI STEFANO , MANTICA MASSIMO , COLTORTI FERNANDO , CORBUCCI GIORGIO , SUTTON RICHARD
Published: July 2003

PADELETTI, L., et al.: How to Test Mode Switching in Pacemakers Implanted in Patients: The MOST Study. Optimal management of atrial arrhythmias with dual chamber pacemakers requires proper performance of automatic mode switching (AMS). The aim of this study was to develop a reliable technique to test the AMS function by using an external electronic device capable of mimicking the occurrence of supraventricular arrhythmias (Supraventricular Arrhythmia Simulator [SAS]). The SAS delivers low voltage pulse trains (200 mV, 20 ms) through two skin electrodes. Each pulse train lasts 15 seconds and starts synchronously with a pacing pulse of the implanted pacemaker to avoid interference from the operator. The pulse train rate is set at 350, 250, and 160 beats/min to simulate AF, atrial flutter, and atrial tachycardia (AT), respectively. Thirty‐five patients implanted with Vitatron pacemakers, whose AMS system has been previously validated, were enrolled. Atrial and ventricular sensing were programmed in unipolar mode at 0.5 mV and in bipolar mode at > 2 mV, respectively. All pulses from the SAS were detected by the atrial channel at an amplitude ranging from 1 to 3 mV. The test proved to be safe and reliable at rest and during exercise. AMS occurred immediately at onset or at offset of atrial arrhythmias, and no adverse interference on pacemaker function was seen from the SAS. In conclusion, the described technique and the SAS are safe and reliable for patient and pacemaker function and can be proposed as a useful method to verify proper performance of AMS function irrespective of the type of implanted devices.
Rapid Recovery of Cardiac Function after Catheter Ablation of Persistent Junctional Reciprocating Tachycardia in Children
Authors: NOË PIETER , VAN DRIEL VINCENT , WITTKAMPF FRED , SREERAM NARAYANSWAMI
Published: July 2003

NOË, P., et al.: Rapid Recovery of Cardiac Function after Catheter Ablation of Persistent Junctional Reciprocating Tachycardia in Children. Four children (age range 3 weeks to 15 years) with tachycardia induced cardiomyopathy due to permanent junctional reciprocating tachycardia (PJRT) underwent successful catheter ablation of the tachyarrhythmia circuit without any complications during or after the procedure. In all four patients, the left ventricular fractional shortening improved to normal within 2 weeks of the procedure. These results argue for a more aggressive approach to the therapy of PJRT when associated with tachycardiomyopathy at a young age.
Optimal Atrioventricular Delay Setting Determined by QT Sensor of Implanted DDDR Pacemaker
Authors: ISHIKAWA TOSHIYUKI , SUGANO TERUYASU , SUMITA SHINICHI , TODA NORITAKA , KOSUGE MASAMI , KOBAYASHI IZUMI , MATSUSITA KOHEI , OHKUSU YASUO , KIMURA KAZUO , USUI TAKASHI , UMEMURA SATOSHI
Published: July 2003

ISHIKAWA, T., et al.: Optimal Atrioventricular Delay Setting Determined by QT Sensor of Implanted DDDR Pacemaker. QT interval (QTI) may change when cardiac function is improved by optimizing the AV delay. QTI is used as the sensor for rate responsive pacemakers. Evoked (e)QTI is measured as the time duration from the ventricular pace‐pulse to the T sense point, which is the steepest point of the intracardiac T wave. The relationship between AV delay and eQTI and cardiac function was studied in 13 patients (74.2 ± 9.3 [SD] years old) with an implanted QT‐driven DDDR pacemaker. A special pacemaker software module was downloaded into the pacemaker memory for eQTI data logging. AV delay was set at 100, 120, 150, 180, 210, and 240 ms. Cardiac output (CO) was measured by continuous Doppler echocardiography. eQTI was 343.3 ± 22.4, 345.1 ± 22.5, and 343.4 ± 23.2 ms (P < 0.01, repeated ANOVA) and CO was 4.2 ± 0.8, 4.6 ± 0.8, and 4.2 ± 0.8 L/min (P < 0.0001, repeated ANOVA) when AV delay was set at the AV delay shortened by one step (AV[−]) and prolonged by one step (AV[+]) from the AV delay at which QT interval was maximum (AV[max]) in seven patients, in whom the peak AV delay at which the eQTI was maximal could be identified. eQTI decreased from 341.1 ± 20.9 to 339.4 ± 21.1 ms (P < 0.0001) and CO decreased from 4.4 ± 1.4 to 4.1 ± 1.3 L/min (P < 0.005) when AV delay was prolonged from AV(max) to AV(+) in all patients. eQTI decreased from 345.1 ± 22.5 to 343.3 ± 22.4 ms (P < 0.0005) and CO decreased from 4.6 ± 0.8 to 4.2 ± 0.8 L/min (P < 0.05) when AV delay was shortened from AV(max) to AV(−) in seven patients. Thus, CO was maximal when AV delay was set at the AV delay at which eQTI was maximal. In conclusion, the optimal AV delay can be predicted from the eQTI sensed by an implanted pacemaker, and automatic setting of the optimal AV delay can be achieved by the QT sensor of an implanted pacemaker.
Restored Atrial Excitability After Late Recanalization in a Patient with Atrial Standstill and Acute Myocardial Infarction
Authors: KOSHIMIZU TAKA‐AKI , KOMORI SADAYOSHI , ISHIHARA TSUKASA , KOHNO ISAO , UMETANI KEN , SAWANOBORI TAKAO , IJIRI HIROSHI , TAMURA KOHJI
Published: July 2003

KOSHIMIZU, T‐A., et al.: Restored Atrial Excitability After Late Recanalization in a Patient with Atrial Standstill and Acute Myocardial Infarction. Atrial standstill is electrophysiologically characterized by the loss of spontaneous excitation in atrial muscle and the inability to cause action potential firing upon electrical stimulation. Clinical diagnosis of transient standstill of the right atrium was made in a patient with acute occlusion of the right coronary artery and acute renal failure. Percutaneous coronary intervention, performed 5 days after the onset, restored the coronary blood flow and resulted in full recovery of electrical activity and regular sinus rhythm.
Severe Mitral Regurgitation with Right Ventricular Pacing, Successfully Treated with Left Ventricular Pacing
Authors: NÚNEZ AMBROSIO , ALBERCA MARÍA TERESA , COSÍO FRANCISCO G. , PASTOR AGUSTÍN , MONTERO MARIAN , RAMOS MARÍA , CARBONELL RAÚL
Published: July 2003

NÚNEZ, A., et al.: Severe Mitral Regurgitation with Right Ventricular Pacing, Successfully Treated with Left Ventricular Pacing. A case of severe mitral regurgitation with refractory heart failure, after atrioventricular junction ablation and pacemaker implant, was solved with left ventricular pacing. Mitral regurgitation was related to a change in segmental left ventricular motion during right ventricular pacing.
Magnesium Deficiency During Lactation as a Precipitant of Ventricular Tachyarrhythmias
Authors: MELA THEOFANIE , GALVIN JOSEPH M. , MCGOVERN BRIAN A.
Published: July 2003

MELA, T., et al.: Magnesium Deficiency During Lactation as a Precipitant of Ventricular Tachyarrhythmias. A young ICD recipient with a history of syncope and idiopathic polymorphic ventricular tachycardia/ventricular fibrillation presented after an ICD discharge. She had delivered her first child 8 days prior to the event and she had been lactating. Numerous short runs of polymorphic ventricular tachycardia/ventricular fibrillation resolved with aggressive replacement of magnesium and elimination of breast‐feeding.
Implantation of a Single Chamber Pacemaker in Patients with Triple Mechanical Valve Prosthesis: Utilization of Coronary Sinus Distal Branches to Stimulate the Left Ventricle
Authors: CURNIS ANTONIO , MASCIOLI GIOSUÈ , BIANCHETTI FEDERICO , BONTEMPI LUCA , MARCONI RENATO , D'ALOIA ANTONIO , CAS LIVIO DEI
Published: July 2003

CURNIS, A., et al.: Implantation of a Single Chamber Pacemaker in Patients with Triple Mechanical Valve Prosthesis: Utilization of Coronary Sinus Distal Branches to Stimulate the Left Ventricle. The implantation of a permanent pacemaker and its relative leads is still a challenge in patients with mechanical tricuspid valve prosthesis. The implant is usually performed epicardially or during valve replacement to avoid any damage to the valve and/or early damages to the lead. We describe the case of a patient with a tricuspid valve prosthesis implanted with a permanent single‐chamber pacemaker using an endocardial lead positioned in a distal branch of the coronary sinus to stimulate the left ventricle.
Georges Weiss' Fundamental Law of Electrostimulation Is 100 Years Old
Authors: IRNICH WERNER
Published: July 2003

IRNICH W.: Georges Weiss' Fundamental Law of Electrostimulation Is 100 Years Old. In 1901, Georges Weiss published a voluminous paper that was the result of the charge by the Commission International du Parc‐aux‐Prince to investigate whether there are measures to make mutually comparable and to classify the different devices that physiologists used for nerve and muscle stimulation. Georges Weiss was born August 26, 1859 in Bischweiler (Alsace, France). He trained as an engineer in Paris and afterward began his medical training and received his medical doctorate in 1889. In the same year he was appointed “Professeur Agrègé,” and “Préparateur” at the Department of Medical Physics of the Medical Faculty at Paris. He made many contributions to physiology, but his main field of interest was electrophysiology. At the end of the nineteenth century the measuring capabilities for electrical stimulation pulses were limited and stimulation theories were based more on speculation than on measurements. Weiss found a fascinating method to produce short‐lasting pulses of defined amplitude and duration. He constructed bridges by conducting threads within a circuit that were then destroyed by an air rifle bullet driven by liquid carbonic acid to produce short‐lasting pulses. To investigate double pulses, the measuring system was expanded in the same manner, now with four bridging threads. The experiments were carried out with remarkable accuracy. The results included: (1) the threshold quantity that is the voltage‐time‐product, is a linear function of the pulse duration; (2) there is always a minimum of the delivered energy dependent on pulse duration; (3) pulse shape plays no role in electrostimulation. The physiologists were not so impressed by the Weiss report as it did not really meet the requirements as expressed by the title. There was no measuring technology available at that time to measure the quantity of devices with short‐lasting pulses in the millisecond range. No wonder that the importance of the findings was not really perceived by the scientific community. It can be concluded that if there are statements in the literature contradicting one of the above three Weiss theorems, one can infer that the investigation is questionable.
Criteria for Pacemaker Explant in Patients Without a Precise Indication for Pacemaker Implantation
Authors: MARTINELLI MARTINO , COSTA ROBERTO , NISHIOKA SILVANA , PEDROSA ANÍSIO , SIQUEIRA SÉRGIO , CREVELARI ELIZABETH , SCANAVACCA MAURÍCIO , D'ÁVILA ANDRÉ , SOSA EDUARDO
Published: July 2003

MARTINELLI, M., et al.: Criteria for Pacemaker Explant in Patients Without a Precise Indication for Pacemaker Implantation. Unnecessary pacemaker implantation may cause significant social and psychological consequences, the inconvenience of periodic office visits, and the expense of pulse generator replacement. Establishing adequate criteria for explanting pacemakers is crucial and has not yet been described. This study presents the results of a study protocol for explanting the pacemaker in patients without a clear indication for pacemaker implantation. Seventy pacemaker users without a clear reason for the implantation were included in the study conducted from August 1986 to November 1998 and were prospectively followed. The investigation consisted of clinical and neurological evaluations, echocardiogram, exercise testing, and tilt table testing. When these tests were negative, the pulse generator energy and stimulation rates were reprogrammed to the lowest values. Periodic Holter monitoring was conducted during follow‐up. When asymptomatic for 1 year, patients underwent an electrophysiological evaluation of sinus and atrioventricular junction function and ventricular vulnerability. When the electrophysiological study was negative, pacemaker explantation was performed. Of the 70 patients, 35 had their pacemaker explanted; 3 were excluded due to a positive tilt table test and electrophysiological study, and 3 are waiting for pacemaker explantation. Mean follow‐up after pacemaker explantation was 30.3 months, and all patients remained asymptomatic, except for one patient who died of a noncardiac cause. Critical analysis of pacemaker users without a well‐established indication is justified because it may allow pacemaker explant in a significant proportion of these patients, and it may bring considerable social, economic, and psychological benefits.
Human Experience with Transvenous Biventricular Defibrillation Using an Electrode in a Left Ventricular Vein
Authors: BUTTER CHRISTIAN , MEISEL ECKHART , ENGELMANN LOTHAR , ELDAR MICHAEL , FLECK ECKARD , SCHUBERT BERND , HAHN STEPHEN , MICHEL ULRICH , PFEIFFER DIETRICH
Published: July 2003

BUTTER, C., et al.: Human Experience with Transvenous Biventricular Defibrillation Using an Elec‐trode in a Left Ventricular Vein. This study investigated the safety and feasibility of transvenous biventricular defibrillation in ICD patients. Some patients may have high DFTs due to weak shock field intensity on the LV. Animal studies showed a LV shocking electrode dramatically lowered DFTs. This approach might benefit heart failure patients already receiving a LV lead or conventional ICD patients with high DFTs. A modified guidewire was used as a temporary left venous access defibrillation electrode (LVA lead). In 24 patients receiving an ICD, the LVA lead was advanced through a guide catheter in the coronary sinus (CS) and into a randomized LV vein (anterior or posterior) using a venogram for guidance. Paired DFT testing compared a standard right ventricular defibrillation system to a biventricular defibrillation system. There were no complications or adverse events. As randomized, LVA lead insertion success was 87% and 71% for anterior and posterior veins, respectively, and 100% after crossover. Total insertion process time included venogram time (32.5 ± 26.9 minutes, range 5–115, mode 15 minutes) and LVA lead insertion time (15 ± 14 minutes, range 1–51, mode 7 minutes). An apical LVA lead position was achieved in 11 (45%) of 24 patients and 7 (64 %) of these 11 displayed a DFT reduction; however, mean DFTs were not statistically different. Transvenous biventricular defibrillation is feasible and was safe under the conditions tested. Additional clinical studies are justified to determine if optimized LV lead designs, lead placement, and shock configurations can yield the same large DFT reductions as observed in animals.
Prospective Assessment After Pediatric Cardiac Ablation: Design and Implementation of the Multicenter Study
Authors: VAN HARE GEORGE F. , CARMELLI DORIT , SMITH W. MCFATE , KUGLER JOHN , SILKA MICHAEL , FRIEDMAN RICHARD , ATKINS DIANNE , SAUL J. PHILIP , SCHAFFER MICHAEL , BYRUM CRAIG , DUNNIGAN ANN , COLAN STEVEN , SERWER GERALD ,   PARTICIPATING MEMBERS OF THE PEDIATRIC ELECTROPHYSIOLOGY SOCIETY
Published: July 2003

VAN HARE, G.F., et al.: Prospective Assessment After Pediatric Cardiac Ablation: Design and Imple‐mentation of the Multicenter Study. A multicenter prospective study was designed and implemented as an activity of the Pediatric Electrophysiology Society to assess the risks associated with radiofrequency ablation in children. Patients (age 0–15 years) with supraventricular tachycardia due to accessory pathways or atrioventricular nodal reentry were enrolled and studied prior to ablation and periodically by clinical evaluation, electrocardiogram (ECG), Holter monitor, and echocardiogram. In addition, a national registry was established, to which the contributing centers report all pediatric patients undergoing ablation at their center. Initial electrophysiological study tracings and all noninvasive studies undergo blinded outside review for quality control. Clinical endpoints were death, recurrence, proarrhythmia, and echocardiographic abnormality. A pilot study demonstrated excellent agreement concerning diagnoses of previously reported ablation patients between the reporting center and the blinded reviewer (kappa = 0.938 ± 0.062). A total of 317 patients were enrolled in the ongoing study from April 1, 1999 to December 31, 2000. The success rate of ablations was 96% with a complication rate of 4.3% for electrophysiological study and 2.9% for the ablation procedure. Comparison of the registry group versus the study group shows that the groups are comparable in terms of patient characteristics, diagnoses, and the results of ablation making it less likely that the sample of prospectively enrolled patients is biased.
Gross Structure of the Atriums: More Than an Anatomic Curiosity?
Authors: HO SIEW YEN , ANDERSON ROBERT H. , SÁNCHEZ‐QUINTANA DAMIÁN
Published: July 2003

HO, S.Y., et al.: Gross Structure of the Atriums: More Than an Anatomic Curiosity? Despite the extensive literature concerning atrial arrhythmias, there are relatively few articles on the anatomy of the atrial chambers. Since electrophysiological mapping and interventional treatments of atrial arrhythmias involve entering the chambers, this article reviews the gross structures to provide a better understanding of the atriums, the septum, and the connecting great veins. In addition, based on the human heart, differences between porcine and canine hearts are highlighted. The right and left atriums are characterized by morphologically distinct appendages. The right atrium contains prominent muscular bundles and an extensive array of pectinate muscles. The distal ramifications of the terminal crest lead to the “flutter” isthmus. By contrast, the left atrium has relatively smooth walls. The atrial septum is limited to the valve of the oval fossa and its immediate muscular rim. Atrial musculature extends beyond the veno‐atrial junctions to the outside of the pulmonary veins. The longest sleeves are around the upper pulmonary veins, and similar sleeves are seen around the superior caval vein. The structure of the atrium is more than an anatomic curiosity. It has practical implications for mapping and interventional procedures.
Radiofrequency Ablation of Sustained Ventricular Tachycardia Related to the Mitral Isthmus in Chagas' Disease
Authors: SCANAVACCA MAURICIO , SOSA EDUARDO , D'ÁVILA ANDRÉ , LOURDES HIGUCHI MARIA DE
Published: July 2003

SCANAVACCA, M., et al.: Radiofrequency Ablation of Sustained Ventricular Tachycardia Related to the Mitral Isthmus in Chagas' Disease. This case report describes the electrophysiological findings of a 62‐year‐old patient with chronic Chagas' disease and two distinct morphologies of sustained ventricular tachycardia that involved a mitral isthmus. Multiple RF applications were necessary to obtain a bidirectional conduction block in the mitral isthmus that was related to the interruption of both tachycardias. After the procedure, the patient presented massive cerebral infarction that progressed to coma and death. Autopsy showed acute and old lesions at the mitral isthmus and recent mitral annulus thrombosis.
Successful Radiofrequency Current Catheter Ablation of Accessory Atrioventricular Pathway in Ebstein's Anomaly using Electroanatomic Mapping
Authors: AI TOMOHIKO , IKEGUCHI SHIGERU , WATANUKI MASATO , AMAYA NAOKI , NINOMIYA TOMONORI , HORIE MINORU , KAWAI CHUICHI
Published: July 2003

AI, T., et al.: Successful Radiofrequency Current Catheter Ablation of Accessory Atrioventricular Path‐way in Ebstein's Anomaly using Electroanatomic Mapping. Ebstein's anomaly is highly associated withEbstein's anomaly is highly associated with atrioventricular reciprocating tachycardia (AVRT) due to an atrioventricular accessory pathway (AP). This case report describes a case of a 30‐year‐old man with Ebstein's anomaly who had been suffering from recurrent palpitation caused by AVRT due to the right‐sided AP. Conventional mapping technique failed to ablate his AP successfully. In baseline electrophysiological study, orthodromic AVRT with a right posterior AP were induced. The AP was mapped using an electroanatomic mapping system. RF current was successfully delivered at the posterior site. RFCA using an electroanatomic mapping system seems to be useful for AVRT patients in Ebstein's anomaly.
Constrictive Pericarditis Complicating Endovascular Pacemaker Implantation
Authors: ELINAV ERAN , LEIBOWITZ DAVID
Published: July 2003

ELINAV, E., et al.: Constrictive Pericarditis Complicating Endovascular Pacemaker Implantation. A patient is described who has 6 months of progressive dyspnea and peripheral edema for 4 years following implantation of an endovascular pacemaker, which was complicated by a large hemorrhagic pericardial effusion. Evaluation was consistent with constrictive pericarditis, which is an extremely unusual complication of pacemaker implantation.
Pacemaker Pocket Infection Due to Acremonium Species
Authors: KOUVOUSIS NICOLAOS , LAZAROS GEORGE , CHRISTOFORATOU EVANGELLIA , DEFTEREOS SPIRIDON , PETROPOULOU‐MILONA DIMITRA , LELEKIS MOYSSIS , ZACHAROULIS APOSTOLOS
Published: July 2003

KOUVOUSIS, N., et al.: Pacemaker Pocket Infection Due to Acremonium Species. Fungal infections involving the pacemaker pocket after pacemaker implantation procedure are extremely rare. This report describes the case of a 53‐year‐old woman with pacemaker pocket infection due to acremonium species. The authors emphasize that this patient did not have any predisposing factors to fungal infections.
Mapping the Coronary Sinus and Great Cardiac Vein
Authors: GIUDICI MICHAEL , WINSTON STUART , KAPPLER JAMES , SHINN TIMOTHY , SINGER IGOR , SCHEINER AVRAM , BERRIER HELEN , HERNER MARK , SAMPLE ROSS
Published: July 2003

GIUDICI, M., et al.: Mapping the Coronary Sinus and Great Cardiac Vein. The purpose of this study was to develop a better understanding of the pacing and sensing characteristics of electrodes placed in the proximal cardiac veins. A detailed mapping of the coronary sinus (CS) and great cardiac vein (GCV) was done on 25 patients with normal sinus rhythm using a deflectable electrophysiological catheter. Intrinsic bipolar electrograms and atrial and ventricular pacing voltage thresholds were measured. For measurement purposes, the GCV and the CS were each subdivided into distal (D), middle (M), and proximal (P) regions, for a total of six test locations. Within the CS and GCV, the average atrial pacing threshold was always lower (P < 0.05) than the ventricle with an average ventricular to atrial ratio > 5, except for the GCV‐D. The average atrial threshold in the CS and GCV ranged from 0.2– to 1.0‐V higher than in the atrial appendage. Diaphragmatic pacing was observed in three patients. Atrial signal amplitude was greatest in the CS‐M, CS‐D, and GCV‐P and smaller in the CS‐P, GCV‐M, and GCV‐D. Electrode spacing did not significantly affect P wave amplitude, while narrower electrode spacing attenuated R wave amplitude. The average P:R ratio was highest with 5‐mm‐spaced electrodes compared to wider spaced pairs. The P:R ratio in the CS was higher (P < 0.05) than in all positions of the GVC. It is possible to pace the atrium independent of the ventricle at reasonably low thresholds and to detect atrial depolarization without undue cross‐talk or noise using closely spaced bipolar electrode pairs. The areas of the proximal, middle, and distal CS produced the best combination of pacing and sensing parameters.
QT Interval in Children with Sensory Neural Hearing Loss
Authors: EL HABBAL MAGDI H. , MAHONEY C.O.
Published: July 2003

EL HABBAL, M.H., et al.: QT Interval in Children with Sensory Neural Hearing Loss. Long QT syndrome was first described in children with congenital sensory neural hearing loss (SNHL). The deafness was attributed to abnormalities in potassium ion channels of the inner ear. Similar channels are present in the heart and its dysfunction causes long QT syndrome. Whether congenital SNHL is associated with prolonged QT is unknown. This study examined 52 patients (median age 8.35 years, range 0.21–17.42 years) with SNHL and compared them to 63 healthy children (median age 10.2 years; range 0.67–19 years). An observer, who was blinded from the presence or absence of SNHL, measured QT, QTc intervals and dispersions from a standard 12‐lead electrocardiogram. To assess the cardiac autonomic enervation, power spectral analysis of heart rate variability was determined using a 24‐hour ambulatory heart rate monitor and was expressed as high (HF) to low frequency (LF) ratio. Left ventricular size and functions were evaluated by using two‐dimensional echocardiography. The medians (and ranges) of QT intervals were 340 ms (230–420 ms) in patients and 320 ms (240–386 ms) in the control group (P < 0.01). The QTc was longer in patients with SNHL (median 417 ms, range 384–490 ms) than in controls (median 388 ms, range 325–432 ms, P < 0.001). QT dispersions in SNHL were higher (median .038 ms, range 00–11 ms) than controls (median 27 ms, range 00–52 ms, P < 0.001). T wave inversion (n = 16) and alternans (n = 3) occurred in patients with SNHL. Heart rates were similar in both groups. Some deaf patients (n = 8) had dizzy episodes with a QTc > 440 ms. The HF:LF ratio was 1.32 (0.516–2.33) in deaf patients and 1.428 (0.67–2.3) in the control group (P > 0.1). Left ventricular size and functions were similar and normal in deaf patients and controls. In children, congenital SNHL is associated with a prolonged QT interval.
Radiofrequency Catheter Ablation Using Cooled Electrodes: Impact of Irrigation Flow Rate and Catheter Contact Pressure on Lesion Dimensions
Authors: WEISS CHRISTIAN , ANTZ MATTHIAS , EICK OLAF , ESHAGZAIY KABLAI , MEINERTZ THOMAS , WILLEMS STEPHAN
Published: July 2003

WEISS, C., et al.: Radiofrequency Catheter Ablation Using Cooled Electrodes: Impact of Irrigation Flow Rate and Catheter Contact Pressure on Lesion Dimensions. Irrigation of radiofrequency current (RF) ablation reduces the risk of thrombus formation. The aim of this study was to investigate the impact of different irrigation catheter flow rates and contact pressures from the catheter on the development of lesion dimension and thrombus formation. A thigh muscle preparation was achieved in six sheep to create a cradle that was filled and perfused with heparinized blood (250 mL/min, 37C°). RF ablation (30 s, 30 W) was initially performed with three different irrigation flow rates (5 mL/min, 10mL/min, and 20 mL/min) and a perpendicular position (0.1 N contact pressure) of the irrigated ablation catheter (“Sprinklr,” Medtronic, Inc., Minneapolis, MN, USA). The next lesions were induced with constant contact pressure of 0.05 Newton (N); 0.1 N; 0.3 and 0.5 N and a parallel or perpendicular orientation of the catheter, respectively. A constant irrigation flow of 10 mL/min was maintained during these RF applications. Cross sections of the lesions were investigated with regard to maximal depth and maximal diameter at and below the surface. During high flow irrigation (20 mL/min) the surface diameter was significantly smaller (0.63 ± 0.1 cm) compared to irrigation flow rates of 5 mL/min (0.88 ± 0.2 cm) and 10 mL/min (1 ± 0.1 cm). Thrombus formation was not observed during any RF application. Only in perpendicular catheter orientations with a contact pressure of 0.5 N were significantly deeper lesions (0.85 ± 0.12 cm) induced compared to 0.05 N (0.55 ± 0.02 cm), 0.1 N (0.7 ± 0.01 cm) and 0.3 N (0.67 ± 0.01 cm) contact pressure. There was no significant difference in lesion depth with different flow rates. Irrigated RF ablation even with low flow rates and high catheter contact pressure prevented thrombus formation at the electrode. Smaller lesion diameters have been created with high irrigation flow rates. The deeper lesion created with high catheter contact pressure might be caused by a greater power transmission to the tissue.
An Unusual Case of Pacemaker Failure: Complete Disconnection of Connector Block and Battery of a Subpectorally Implanted Dual Chamber Pacemaker
Authors: MELLERT FRITZ , ESMAILZADEH BAHMAN , SCHNEIDER CHRISTIAN , HAUSHOFER MARCUS , SCHIMPF RAINER , WOLPERT CHRISTIAN , PREUSSE CLAUS J. , LÜDERITZ BERNDT , WELZ ARMIN
Published: July 2003

MELLERT, F., et al.: An Unusual Case of Pacemaker Failure: Complete Disconnection of Connector Block and Battery of a Subpectorally Implanted Dual Chamber Pacemaker. Local trauma to patients with implanted pacemaker devices may result in lead fracture or breakage of the lead socket with leakage of fluid into the connector system. This report describes an unusual case of complete entrance and exit block in a subpectorally implanted dual chamber pacemaker due to total disconnection and dislodgement of header block and battery part. Damage may be caused by an interaction of machine fatigue/manufacturing defective and fixation of the header with unusual movability of the battery, leading to breakage with intermittent malfunction and consecutive bradycardia and syncope.
Brugada Syndrome: A Case Report of an Unusual Association with Vasospastic Angina and Coronary Myocardial Bridging
Authors: IMAZIO MASSIMO , GHISIO ALDO , CODA LUISELLA , TIDU MASSIMO , BELLI RICCARDO , TRINCHERO RITA , BRUSCA ANTONIO
Published: July 2003

IMAZIO, M., et al.: Brugada Syndrome: A Case Report of an Unusual Association with Vasospastic Angina and Coronary Myocardial Bridging. This report describes a case of an unusual association between vasospastic angina, coronary myocardial bridging, and Brugada syndrome. The patient complained of chest pain followed by rhythmic palpitation and syncope. Brugada syndrome ECG markers were documented with transient ST‐segment elevation in lateral leads. A coronary angiogram showed a myocardial bridging in the left anterior descending artery and coronary vasospasm was reproduced after intracoronary ergonovine injection in the circumflex coronary artery. Ventricular fibrillation was induced by programmed electrical stimulation. The described association can be important because interaction between ischemia and Brugada syndrome electrophysiological substrate could modulate individual susceptibility to life‐threatening ventricular tachyarrhythmias.
Inadvertent Detection of 60‐Hz Alternating Current by an Implantable Cardioverter Defibrillator
Authors: LEE SUNG W. , MOAK JEFFREY P. , LEWIS BRIAN
Published: July 2003

LEE, S.W., et al.: Inadvertent Detection of 60‐Hz Alternating Current by an Implantable Cardioverter De‐fibrillator. A patient with an ICD received therapies from his ICD while exercising in an indoor swimming pool. Interrogation of the ICD revealed inappropriate detection of 60‐Hz alternating current artifact and delivery of ICD therapies.