bluuebunny/crossref_metadata_2025 huggingface dataset:
How Can We Identify the Best Implantation Site for an ECG Event Recorder?
Authors: ZELLERHOFF CHRISTIAN , HIMMRICH EWALD , NEBELING DIRK , PRZIBILLE OLIVER , NOWAK BERND , LIEBRICH ANDREAS
Published: July 2003

ZELLERHOFF, C., et al.: How Can We Identify the Best Implantation Site for an ECG Event Recorder? The aim of this study was to show how to find the preferable implantation site for an ECG event recorder (ECG‐ER). We compared the quality of bipolar ECG recordings (4‐cm electrode distance, vertical position) in 65 patients at the following sites: left and right subclavicular, left and right anterior axillary line (4th‐5th interspace), left and right of the sternum (4th‐5th interspace), heart apex, and subxyphoidal. The results were compared to the standard ECG lead II. In 30 patients, an additional comparison between vertical and horizontal ECG registrations was done using the same sites. ECG signals in five patients were compared positioning the electrodes towards the skin with turning them towards the muscle during ECG‐ER implantation. The best ECG quality (defined as highest QRS amplitude, best visible P wave and/or pacemaker spike, best measurable QRS duration, and QT interval) and best agreement with the standard lead II was found in 68% on the left of the sternum, significantly less often (P < 0.001) on the right of the sternum (14.1%), left subclavicular (6.9%), apical (5.5%) and subxyphoidal (4.2%). A significantly higher QRS amplitude was measured and the P wave was more often visible in the vertical electrode position than in the horizontal position. In all five ECG‐ER patients, there was a good agreement between the bipolar surface ECG at the implantation site and ECG‐ER stored signals. A significant noise signal occurred in all five patients when the ECG‐ER was implanted with electrodes towards the muscle. A P wave was visible in only three of those patients, but there was an insignificantly higher QRS amplitude than in ECG‐ERs implanted with electrodes towards the skin. From these results, it can be concluded that the best implantation site for an ECG‐ER is right or left of the sternum, positioning the electrodes vertically and towards the skin.
Concealed Accessory Pathway Manifesting Clinically Only After Pacemaker Implantation
Authors: PINSKI SERGIO L. , TROHMAN RICHARD G.
Published: July 2003

PINSKI, S.L., et al.: Concealed Accessory Pathway Manifesting Clinically Only After Pacemaker Implantation. A 66‐year‐old man with coronary artery disease and persistent left superior vena cava received a DDDR pacemaker for symptomatic 2:1 heart block. There was no previous history of tachyarrhythmias. Endless loop tachycardia and repetitive nonreentrant ventriculoatrial synchrony occurred afterwards and were triggered by a late coupled atrial premature beat. ECGs suggested a concealed left posterior accessory pathway that was confirmed during electrophysiological study. Effective palliation was achieved with extension of the PVARP and enabling noncompetitive atrial pacing operation.
Device Eccentricity: Postmagnet Behavior of DDDR Pacemakers with Automatic Threshold Tracking
Authors: LEVINE PAUL A. , MORAN MICHAEL J.
Published: July 2003

LEVINE, P.A., et al.: Device Eccentricity: Postmagnet Behavior of DDDR Pacemakers with Automatic Threshold Tracking. The normal pacing system function associated with the AutoCapture Pacing System algorithm triggered concern on the part of the clinical staff caring for the patient when the initiation of a threshold search sequence was detected during a transtelephonic follow‐up evaluation. The analysis of the rhythm demonstrates that the behavior of the system is normal and consistent with the design of the AutoCapture algorithm. As a variety of new algorithms are introduced, similar unexpected but normal behaviors can be anticipated.
Insertable Loop Recorder in Unmasking the Cause of Syncope
Authors: SIMANTIRAKIS EMMANUEL N. , CHRYSOSTOMAKIS STAVROS I. , MANIOS EMMANUEL G. , VARDAS PANOS E.
Published: July 2003

SIMANTIRAKIS, E.N., et al.: Insertable Loop Recorder in Unmasking the Cause of Syncope. During the last few years closed loop recorders are being used increasingly in the investigation of unexplained syncope. Our patient had a 5‐year history of pre‐ and syncopal episodes in which the usual invasive and noninvasive tests were nondiagnostic. Finally, a loop recorder was implanted that revealed the cause of the syncope a few days after implantation: a fast, sustained, ventricular tachycardia originating from the right ventricular outflow tract. Loop recorders will undoubtedly contribute toward the decrease in the percentage of undiagnosed syncope cases and possibly to the reduction of the investigation cost.
Transvenous Pacemaker Insertion Ipsilateral to Chronic Subclavian Vein Obstruction: An Operative Technique for Children and Adults
Authors: OVADIA MARC , COOPER RUBIN S. , PARNELL VINCENT A. , DICAPUA DOMINICK , VATSIA SHEEL K. , VLAY STEPHEN C.
Published: July 2003

OVADIA, M., et al.: Transvenous Pacemaker Insertion Ipsilateral to Chronic Subclavian Vein Obstruction: An Operative Technique for Children and Adults. Subclavian vein occlusion limits insertion of pacing electrodes in children and adults. The concern is greatest in children with a long‐term need for pacing systems necessitating use of the contralateral vein and potential bilateral loss of access in the future. We describe an operative technique to provide ipsilateral access in chronic subclavian vein occlusion in five consecutive pediatric (n = 4, mean age 6.5 years) and adult (n = 1, age 70 with bilateral subclavian vein occlusion) patients in whom this condition was noted at the time of pacemaker or ICD implant. Occlusion was documented by venography. Pediatric cardiac diagnoses included complete heart block in all patients, tetralogy of Fallot in three, and L‐transposition of the great vessels in one. Percutaneous brachiocephalic (innominate) or deep subclavian venous access was achieved by a supraclavicular approach using an 18‐gauge Deseret angiocath, a Terumo Glidewire, and dilation to permit one or two 9–11 Fr sheaths. Electrode(s) were positioned in the heart and tunneled (pre– or retroclavicularly) to a pre– or retropectoral pocket. Pacemaker and ICD implants were successful in all without any complication of pneumothorax, arterial or nerve injury, or need for transfusion. Inadvertent arterial access did not occur as compared with prior infraclavicular attempts. One preclavicularly tunneled electrode dislodged with extreme exertion and was revised. Ipsilateral transvenous access for pacemaker or ICD is possible via a deep supraclavicular percutaneous approach when the subclavian venous obstruction is discovered at the time of implant. In children, it avoids the use of the contralateral vein that may be needed for future pacing systems in adulthood. This venous approach provides access large enough to allow even dual chamber pacing in children and can be accomplished safely.
Influence of Sympathetic Heart Rate Modulation on RT Interval Rate Adaptation in Conscious Dogs
Authors: PLADYS PATRICK , MAISON‐BLANCHE PIERRE , GOUT BERNARD , BADILINI FABIO , BRIL ANTOINE , CARRÉ FRANÇOIS
Published: July 2003

PLADYS, P., et al.: Influence of Sympathetic Heart Rate Modulation on R Interval Rate Adaptation In Conscious Dogs. The objective was to test if changes in autonomic tone still influenced the RT‐RR relationship when full RT adaptation is completed, when heart rate is controlled, and when beat‐to‐beat variability is abolished by atrial pacing. Eight dogs (8–11 kg) were chronically instrumented with atrial pacing electrodes. Digital ECG (1,000 Hz, 12 bits) were recorded from healthy conscious dogs during spontaneous sinus rhythm and during atrial pacing. The protocol was repeated before and after atenolol (2 mg/kg), prazosin (0.5 mg/kg), or atenolol + prazosin. A vocal incitation was used as sympathetic stimulation. Beat‐to‐beat quantitative analysis of the RT interval (from QRS apex to end of T wave) was correlated with the preceding RR by linear regression. In spontaneous rhythm, atenolol increased RR (P < 0.001), RT (P < 0.001), and short‐term heart rate variability (P < 0.01) and decreased RT‐RR slopes (P < 0.001). Prazosin did not significantly modify any parameter. Sympathetic stimulation decreased RR (P < 0.001), RT (P < 0.05), and short‐term heart rate variability (P < 0.01) and increased RT‐RR slopes (P < 0.001). In atrial pacing, the RTRR slopes were steeper during pacing than during spontaneous rhythm but were not modified by pharmacological manipulation of the autonomic nervous system. During sinus rhythm the RT‐RR relationship is increased by sympathetic stimulation and decreased by β–blockade. When heart rate modulation and the effects of the time delay in RT rate adaptation are abolished by atrial pacing, the influence of autonomic tone on RT rate adaptation disappears.
High Incidence of Sudden Death with Conduction System and Myocardial Disease Due to Lamins A and C Gene Mutation
Authors: BÉCANE HENRI‐MARC , BONNE GISÈLE , VARNOUS SHAIDA , MUCHIR ANTOINE , ORTEGA VÉRONIQUE , HAMMOUDA EL HADI , URTIZBEREA J‐ANDONI , LAVERGNE THOMAS , FARDEAU MICHEL , EYMARD BRUNO , WEBER SIMON , SCHWARTZ KETTY , DUBOC DENIS
Published: July 2003

BÉCANE, H.–M., et al.: High Incidence of Sudden Death with Conduction System and Myocardial Disease Due to Lamins A and C Gene Mutation. We studied 54 living relatives from a large French kindred, among which 17 members presented with a cardiomyopathy transmitted on an autosomal dominant mode. Five of these individuals had clinical manifestations of muscle disease phenotypically consistent with Emery‐Dreifuss muscular dystrophy. Genetic analysis of this kindred had demonstrated a nonsense mutation in the LMNA gene located on chromosome 1q11–q23. This gene encodes lamins A and C, proteins of the nuclear lamina located on the inner face of the nuclear envelope. We retrospectively determined the cause of death of 15 deceased family members, 8 of whom had died suddenly, 2 as a first and single manifestation of the disease. The six other cases had histories of arrhythmias and left ventricular dysfunction before dying suddenly, and three of them died despite the prior implantation of a permanent pacemaker. The mean age of onset of cardiac symptoms among affected living family members was 33 years (range 15–47 years), and the first symptoms were due to marked atrioventricular conduction defects or sinus dysfunction, requiring the implantation of permanent pacemakers in seven cases. Myocardial dysfunction accompanied by ventricular arrhythmias developed rapidly in the course of the disease and resulted in severe dilated cardiomyopathy requiring cardiac transplantation in three cases. In conclusion, in patients presenting a life‐threatening familial or sporadic cardiac restricted phenotype similar to that described here, mutations in the lamins A and C gene should be looked for. In the genotypically affected individuals, cardiological and electrophysiological follow‐up should be performed to prevent sudden death that could occur rapidly in the evolution of such disease.
Reduction of Symptoms from LVOT Tachycardia Following Inadvertent Fast Pathway Ablation
Authors: FURNISS STEPHEN S. , BOURKE JOHN P. , BEHULOVA RENATA
Published: July 2003

FURNISS, S.S., et al.: Reduction of Symptoms from LVOT Tachycardia Following Inadvertent Fast Pathway Ablation. VT was mapped to above the aortic valve in a young patient with troublesome palpitations. A single 15‐second RF application was inadvertently delivered to a reference His catheter producing permanent first‐degree heart block. The patient has been completely asymptomatic since.
Malignant Neurocardiogenic Vasovagal Syncope Associated with Chronic Exaggerated Vagal Tone
Authors: NAKAGAWA MIKIKO , TAKAHASHI NAOHIKO , YUFU KUNIO , FUJINO TAKAO , OOIE TATSUHIKO , YONEMOCHI HIDETOSHI , NOBE SEIKI , HARA MASAHIDE , SAIKAWA TETSUNORI , ITO MORIO
Published: July 2003

NAKAGAWA, M., et al.: Malignant Neurocardiogenic Vasovagal Syncope Associated with Chronic Exaggerated Vagal Tone. A head‐up tilt test was performed in a 23‐year‐old woman with a history of two syncopal episodes. The patient developed abrupt syncope with 48 seconds of sinus arrest. Analysis of the high frequency (HF) power of heart rate variability over 24 hours before and after metoprolol therapy showed a significantly elevated HF power in this patient compared to age– and sex‐matched healthy subjects. It is suggested that an exaggerated resting vagal tone might be associated with the pathogenesis of prolonged asystole in our patient.
Pacing Alternans: An Unusual Pattern of Pacemaker Behavior
Authors: PAVRI BEHZAD B. , KEEFE JAMES M. , CALLANS DAVID J. , KOCOVIC DUSAN Z.
Published: July 2003

PAVRI, B.B., et al.: Pacing Alternans: An Unusual Pattern of Pacemaker Behavior. We report an unusual pattern of pacemaker function related to the “autocapture” feature of a recently released pacemaker model. The electrocardiogram reveals pacing alternans. This report discusses the differential diagnosis and the correct explanation.
Inability to Communicate with ICDs: An Underreported Failure Mode
Authors: BLITZER MARK L. , MARIEB MARK A. , SCHOENFELD MARK H.
Published: July 2003

BLITZER, M.L., et al.: Inability to Communicate with ICDs: An Underreported Failure Mode. The inability to perform telemetry on an ICD may have many potential causes. We report three recently identified cases where such a finding was indicative of unexpected device failure. Two of these cases involved identical failure mechanisms resulting from arcing of current within the high voltage hybrid. This placed the device into a high current state that caused rapid and complete battery depletion. There were no company alerts issued regarding this systematic problem. A multicenter arrhythmia device/lead database would be extremely useful in providing timely and unbiased information concerning device problems.
Effects of Sex and Age on Electrocardiographic and Cardiac Electrophysiological Properties in Adults
Authors: TANEJA TARESH , WINDHAGEN MAHNERT BRITTA , PASSMAN ROD , GOLDBERGER JEFFREY , KADISH ALAN
Published: July 2003

TANEJA, T., et al.: Effects of Sex, and Age on Electrocardiographic and Cardiac Electrophysiological Properties in Adults. Although differences in patient sex in heart rate and QT interval have been well characterized, sexual differences in other cardiac electrophysiological properties have not been well defined. The study population consisted of 354 consecutive patients without structural heart disease or preexcitation who underwent clinically indicated electrophysiological testing in the drug‐free state. Atrial, AV nodal, and ventricular effective refractory periods (AERP, AVNERP, VERP) were determined at a pacing cycle length of 500 ms using an 8‐beat drive train and 3‐second intertrain pause. There were 124 men and 230 women with a mean age of 45 ± 19 and 47 ± 18 years, respectively The sinus cycle length (SCL) was longer in men than in women (864 ± 186 and 824 ± 172 ms, respectively, P < 0.05). The QRS duration was significantly longer in men (90 ± 12 ms) than women (86 ± 13 ms) (P < 0.005). The HV interval was 48 ± 9 ms in men and 45 ± 8 ms in women (P < 0.05). The sinus node recovery time (SNRT) was significantly longer in men than in women (1215 ± 297 ms and 1135 ± 214 ms, respectively, P < 0.05). AERP and VERP were similar in both sexes. Aging did not influence sexual differences in cardiac electrophysiological properties, although, it independently prolonged the SCL, PR, and QT intervals, AH and HV intervals, SNRT, AVNERP, and the AV Wenckebach cycle length. The SCL, QRS duration, HV interval, and SNRT were significantly longer in men than in women. Aging prolonged cardiac conduction and increased the SCL but the effects were similar in both sexes. AERP and VERP were unaffected by aging or sex.
Septal Lead Implantation for the Reduction of Paced QRS Duration Using Passive‐Fixation Leads
Authors: SCHWAAB BERNHARD , KINDERMANN MICHAEL , FRÖHLIG GERD , BERG MONIKA , KUSCH OLIVER , SCHIEFFER HERMANN
Published: July 2003

SCHWAAB, B., et al.: Septal Lead Implantation for the Reduction of Paced QRS Duration using Passive‐Fixation Leads. In 120 consecutive patients with standard pacing indications, we tested the feasibility of RV septal lead implantation technique guided by surface ECG and the degree to which this technique reduces paced QRS duration compared to RV apical stimulation when passive‐fixation leads are used. During implantation, an ECG was recorded with a paper speed of 100 mm/s using the orthogonal Frank leads, and QRS was measured from the earliest to the latest deflection in any of the Frank leads. Pace‐mapping of the septum was performed until QRS was minimal. The lead was attached, where QRS, pacing threshold, lead impedance, and EGM amplitude provided the best compromise. An average of 3.7 ± 2.5 attempts (range 1–18, median 7) was needed until a final implantation site was found. There were no technical problems during implantation. QRS could be reduced by 5–55 ms (mean Δ QRS 19 ± 11 ms) in 83 (69%) of 120 patients. In 22 (18%) patients, QRS was identical with apical and septal pacing, and in 15 (13%) patients, QRS was 5–20 ms (10 ± 4) longer despite septal stimulation. Average QRS was significantly shorter during septal pacing compared with apical pacing (151 ± 20 vs 162 ± 23 ms, P < 0.001). There was a tendency towards greatest QRS reduction when the high septum was stimulated (22 ± 11 ms reduction) as compared with mid‐ (18 ± 11 ms) or apical parts of the RV septum (16 ± 10 ms). QRS reduction was most likely if apical QRS width was > 170 ms (P = 0.0002), and there was an inverse correlation between apical QRS and Δ QRS (r = 0.53, P < 10‐7). During a mean follow‐up of 14 months, there was no pacing or sensing problem and no lead dislodgment occurred.
Functional Similarity Between Electrograms Recorded from an Implantable Cardioverter Defibrillator Emulator and the Surface Electrocardiogram
Authors: MAZUR ALEXANDER , WANG LI , ANDERSON MARK E. , YEE RAYMOND , THERES HEINZ , PEARSON ANN , OLSON WALTER , WATHEN MARK
Published: July 2003

MAZUR, A., et al.: Functional Similarity Between Electrograms Recorded from an Implantable Cardioverter Defibrillator Emulator and the Surface Electrocardiogram. Clinical use of stored electrogram (EGM) configurations currently used in ICDs is limited. The hypothesis that EGMs recorded from electrodes on the ICD surface may improve diagnostic capabilities of the device was tested in the present study. The Buttons on Active Can Emulator (BACE), an ICD‐sized device containing four button electrodes, was temporarily placed into a subcutaneous or submuscular left pectoral pocket in 16 patients during ICD implantation. Simultaneous recordings were obtained from the ECG lead II, bipolar EGMs using BACE electrodes, and a bipolar atrial EGM during sinus rhythm (SR), ventricular pacing (VP) at cycle lengths of 500 and 400 ms, and VT. Visible P waves were present in all patients during SR (n = 15), in 5 (33%) of 15 patients during VP, and none of the patients during VT (n = 4) using BACE EGMs and lead II. P and QRS amplitudes and the P:QRS ratio during SR in BACE EGMs were significantly lower than those in lead II. BACE EGMs showed prominent changes in QRS morphology and duration during VP and VT compared to SR, and the magnitude of QRS prolongation during VP was similar to that in lead II. Measurements of PR, QRS, and QT duration during SR showed good agreement between BACE EGMs and lead II. In conclusion, EGMs recorded from electrodes embedded on the ICD housing may potentially improve visual discrimination between supraventricular and ventricular arrhythmias. They also may be useful as a surrogate of the ECG for analysis and monitoring of different components of P‐QRS‐T complex.
Paroxysmal Tachycardia in Children and Teenagers with Normal Sinus Rhythm and Without Heart Disease
Authors: BREMBILLA‐PERROT BÉATRICE , MARCON FRANCOIS , BOSSER GILLES , LUCRON HUGUES , HOURIEZ PIERRE , CLAUDON OLIVIER , HOLBAN IOANA , BLANGY HUGUES
Published: July 2003

BREMBILLA‐PERROT, B., et al.: Paroxysmal Tachycardia in Children and Teenagers with Normal Sinus Rhythm and Without Heart Disease. The purpose of this study was to evaluate the value of esophageal programmed stimulation in children and teenagers with normal sinus rhythm ECG and normal noninvasive studies, having palpitations and syncope, and no documented tachycardias. Paroxysmal tachycardias are frequent in children and are often related to accessory connection. These tachycardias are sometimes difficult to prove. Transesophageal atrial pacing was performed at rest and during infusion of isoproterenol in 31 children or adolescents aged 9–19 years (16 ± 3 years) with normal sinus rhythm ECG and suspected or documented episodes of paroxysmal tachycardia. Sustained tachycardia was induced in 27 patients, at rest in 13 patients, and after isoproterenol in 14 remaining patients. Atrioventricular nodal reentrant tachycardia was found as the main cause of paroxysmal tachycardia (22 cases). Six patients were followed by a vagal reaction and dizziness. These patients had spontaneous tachycardia with syncope. In three other patients, atrial fibrillation was also induced. Concealed accessory pathway reentrant tachycardia was identified in three patients. In two patients, a regular wide tachycardia with right bundle branch block morphology was induced; the diagnosis of verapamil‐sensitive ventricular tachycardia was made in a second study by intracardiac study. In conclusion, atrioventricular nodal reentrant tachycardia was found as the main cause of symptoms in children with normal sinus rhythm ECG. Syncope is frequently associated and provoked by a vagal reaction. This diagnosis could be underestimated in adolescents frequently considered as hysterical because noninvasive studies are negative.
Effect of Diabetes Mellitus on Heart Rate Variability in Patients with Congestive Heart Failure
Authors: BURGER ANDREW J. , ARONSON DORON
Published: July 2003

BURGER, A.J., et al.: Effect of Diabetes Mellitus on Heart Rate Variability in Patients with Congestive Heart Failure. This study sought to determine if the severity of autonomic perturbations in patients with heart failure are affected by the presence of diabetes. Decreased HRV is frequent in diabetic patients free of clinically apparent heart disease and has been invoked as a risk factor for sudden cardiac death. However, reduced HRV is also commonly present in patients with left ventricular dysfunction. The effect of diabetes on autonomic dysfunction in this setting is not known. Holter ECGs from 69 diabetic patients and 85 nondiabetic control subjects with heart failure were analyzed. The severity of autonomic dysfunction was assessed using 24‐hour time‐ and frequency‐domain HRV analysis. Prognostically important timeand frequency‐domain HRV measures (SDNN, SDANN5, total power, and ultra‐low frequency power) were not different between the two groups. Time‐ and frequency‐domain parameters modulated by parasympathetic tone (pNN50, RMSSD, and HF power) were depressed to a similar degree in the diabetic and the nondiabetic groups. The low frequency power was significantly lower in diabetic patients (5.8 ± 0.7 vs 5.3 ± 1.0, P = 0.02). The ratio of low to high frequency power was substantially lower in the diabetic group (2.2 ± 0.2 vs 1.4 ± 0.2, P < 0.0001). These differences were more apparent in insulin‐treated diabetics. In the presence of heart failure, HRV parameters that are most predictive of adverse outcome are similar in diabetic and nondiabetic patients. Furthermore, during increased sympathetic stimulation in the setting of heart failure, diabetes does not worsen parasympathetic withdrawal but may mitigate sympathetic activation.
Effect of Lead Exclusion for the Manual Measurement of QT Dispersion
Authors: LANGLEY PHILIP , DI BERNARDO DIEGO , MURRAY ALAN
Published: July 2003

LANGLEY, P., et al.: Effect of Lead Exclusion for the Manual Measurement of QT Dispersion. To investigate the effect of different lead exclusion criteria for the manual measurement of QT dispersion (QTd). Simultaneous 12‐lead ECGs from three groups of 25 subjects were studied; healthy normal subjects, subjects with a myocardial infarction, and subjects with arrhythmias. Leads were excluded with (1) small absolute T wave amplitudes, (2) small relative T wave amplitudes, and (3) small and/or large relative QT measurements. QTd was calculated as the QT range and assessed for its ability to differentiate between the normal and pathological groups. With exclusion of no leads or low absolute amplitude T waves (< 50 μV) significant differences were observed only between normal and myocardial infarct groups (P < 0.05). Significant differences between normal and both pathological groups were observed when excluding the lead with the smallest amplitude T wave or shortest QT (P < 0.05), or when two leads of either type were excluded (P < 0.005). There was good agreement between leads excluded by amplitude or QT (P < 0.01). Lead exclusion for QTd is important. Exclusion of the two smallest amplitude or two shortest QT leads from each subject produced the greatest differences between the normal and pathological groups.
Sunao Tawara: A Father of Modern Cardiology
Authors: SUMA KOZO
Published: July 2003

SUMA, K.: Sunao Tawara: A Father of Modern Cardiology. Knowledge of the conduction system of the heart was greatly advanced by Tawara's work carried out in Aschoff's laboratory in Marburg at the beginning of this century. In his monograph, The Conduction System of the Mammalian Heart, published in 1906, Tawara indicated that the treelike structure of specific muscle fibers comprising the atrioventricular node, His bundle, bundle branches, and Purkinje fibers served as the pathway for atrioventricular conduction of excitation in the mammalian heart. From his own anatomic and histological findings of the conduction system, he assumed precisely that the conduction velocity of excitation in the system, except in the atrioventricular node, would be fast and that contraction as the result of excitation would take place at the various sites of the ventricles almost simultaneously. According to Tawara, a long pathway to each contracting unit and a fast conduction velocity of excitation would be a prerequisite for the effective contraction of the ventricles. Tawara's findings and assumptions provided Einthoven the theoretical basis for interpreting the electrocardiogram, resulting in rapid popularization of electrocardiography. This century has witnessed the rapid progress of cardiology, including cardiac pacing and its related sciences. This progress has its roots in the discovery of the conduction system and the development of electrocardiography that took place almost in the same period at the beginning of this century. Tawara's pioneering work on the conduction system still serves as an invaluable reference for basic and clinical research.
Torsades de Pointes Ventricular Tachycardia Induced by Mosapride and Flecainide in the Presence of Hypokalemia
Authors: OHKI RURI , TAKAHASHI MASAFUMI , MIZUNO OSAMU , FUJIKAWA HIDEYUKI , MITSUHASHI TAKESHI , KATSUKI TAKAAKI , IKEDA UICHI , SHIMADA KAZUYUKI
Published: July 2003

OHKI, R., et al.: Torsades de Pointes Ventricular Tachycardia Induced by Mosapride and Flecainide in the Presence of Hypokalemia. We report a 68‐year‐old man who developed torsades de pointes ventricular tachycardia induced by combined use of mosapride and flecainide. He had a permanent pacemaker (DDD mode) implanted because of sick sinus syndrome (bradytachy syndrome) 6 years earlier. The patient had started taking mosapride for upper abdominal discomfort 2 weeks earlier. On admission, ECG showed prolongation of the QTc interval from 0.48 to 0.56 seconds and self‐terminating torsades de pointes occurred. We considered that this proarrhythmia was induced by mosapride in combination with antiarrhythmic agents.
Psychological Treatment of Malignant Vasovagal Syncope Due to Bloodphobia
Authors: VAN DIJK NYNKE , VELZEBOER SIMONE C.J.M. , DESTRÉE‐VONK ANNEKE , LINZER MARK , WIELING WOUTER
Published: July 2003

VAN DIJK, N., et al.: Psychological Treatment of Malignant Vasovagal Syncope Due to Bloodphobia. A 17‐year‐old boy with frequent faints due to blood‐injury phobia was studied. During cardiovascular reflex investigation in our syncope unit, 50 seconds of asystole were recorded. He was treated using systematic desensitization with muscular tension and cognitive techniques by the Pediatric Psychosocial Department and has not experienced syncopal events again.
RV Function in Stable and Unstable VT: Is There a Need for Hemodynamic Monitoring in Future Defibrillators?
Authors: HEGBOM FINN , HOFF PER I. , ØIE BERTIL , FØLLING MAGNE , ZEIJLEMAKER VOLKERT , LINDEMANS FRED , OHM OLE‐JØRGEN
Published: July 2003

HEGBOM, F., et al.: RV Function in Stable and Unstable VT: Is There a Need for Hemodynamic Monitoring in Future Defibrillators? During electrophysiological investigation of 22 patients with VT or aborted sudden cardiac death, arterial and RV pressures were measured. The time courses of mean arterial pressure (MAP), RV pulse pressure (RVPP), RV pulse pressure integral (RVPPI), and maximum right ventricular dP/dt (RV dP/dtmax) were followed during the first 15 seconds after VT induction. Compared to basal (preinduction) conditions, the RVPPI decreased by 41 ± 10% (mean ± SD) after 10–15 seconds of VT in 11 patients with stable VT and by 75 ± 8% in 11 patients with unstable VT (MAP < 60 mmHg 15 s after VT onset). RVPP decreased by 13 ± 11% after 10–15 seconds of VT in the stable VT group and by 50 ± 16% in the unstable VT group. For RV dP/dtmax, these decreases were 4 ± 22% in the stable VT group and 37 ± 24% in the unstable VT group. There was a good correlation between percent decrease in MAP and percent decrease in RVPPI, RVPP, and RV dP/dtmax at 5–10 seconds (r = 0.86, 0.81, and 0.73, respectively) and 10–15 seconds (r = 0.84, 0.82, and 0.69, respectively) after VT onset. There was hardly any overlap of distributions of the individual values with the RVPPI parameter between the two VT groups. Comparing and correlating the percent decrease in mean arterial pressure with the RVPPI, RVPP, and RV dP/dtmax during induced VT, RVPPI demonstrated the most significant and specific changes in discriminating stable from unstable rhythms. However, by comparing RVPPI and RVPP using the area under the receiver operating characteristic curves, there was no significant statistical difference between the two parameters. By integrating rate criteria, electrogram signal analysis, and RVPPI or RVPP as a hemodynamic criterion, detection and treatment algorithms could improve the performance of future implantable defibrillators and avoiding shocks in VTs that can be terminated by antitachycardia pacing.
Discrimination Between Ventricular and Supraventricular Tachycardia by Dual Chamber Cardioverter Defibrillators: Importance of the Atrial Sensing Function
Authors: ISRAEL CARSTEN W. , GRÖNEFELD GERIAN , ISCOLO NICOLAS , STÖPPLER CHRISTOPH , HOHNLOSER STEFAN H.
Published: July 2003

ISRAEL, C.W., et al.: Discrimination Between Ventricular and Supraventricular Tachycardia by Dual Chamber Cardioverter Defibrillators: Importance of the Atrial Sensing Function. Although the addition of atrial sensing in dual chamber ICDs may improve the ability of the device to discriminate between supraventricular (SVT) and ventricular tachycardia (VT), atrial sensing errors may also negatively affect tachycardia classification. This prospective study evaluated the incidence of atrial sensing errors in a dual chamber ICD and their impact on VT/SVT discrimination. In 145 patients, a dual chamber ICD (Defender) was implanted. Analysis of 1,241 tachycardia episodes stored during a mean follow‐up of 14 ± 8 months revealed atrial sensing errors in 817 (66%) episodes. Upon expert review, device‐based classification was confirmed in 509 (98%) of 522 SVT episodes. No false device‐based SVT classification was related to atrial sensing errors. Of 719 episodes classified as VT by the device, 645 (90%) were confirmed. There were 74 episodes of false‐positive VT detection. Of these, 63 were related to atrial sensing errors: atrial undersensing in 58 (92%) and atrial oversensing in 5 (8%) episodes. Atrial sensing errors led to incorrect VT/SVT discrimination in 51 (4%) of 1,241 episodes. Only the occurrence of paroxysmal atrial fibrillation and abdominal site of device implantation showed a significant influence on false VT/SVT discrimination. Atrial sensing errors are frequently encountered in dual chamber ICDs. Due to the VT/SVT discrimination algorithm, atrial sensing errors only led to misclassification in 4% of all episodes, mainly due to atrial undersensing. No VT underdetection due to atrial oversensing occurred.
Clinical Outcome of Patients Who Develop PAF After CABG Surgery
Authors: KOWEY PETER R. , STEBBINS DAVID , IGIDBASHIAN LISA , GOLDMAN SCOTT M. , SUTTER FRANCIS P. , RIALS SETH J. , MARINCHAK ROGER A.
Published: July 2003

KOWEY, P.R., et al.: Clinical Outcome of Patients Who Develop PAF After CABG Surgery. This was a retrospective analysis of patients who had CABG surgery at our hospital over a 12‐month period to determine the intermediate‐term prognosis of those who had developed PAF after their operation before hospital discharge. Of 317 patients who were operated by a single surgical group, 116 (37%) had AF postoperatively of whom 112 had the paroxysmal form. Of these, 36 were treated with class I or III antiarrhythmic drugs and rate control drugs (group 1) and 76 were treated with rate control alone (group 2). Group 3 consisted of 151 randomly selected patients who did not have AF. All patients were reevaluated at 6 weeks to determine their rhythm and clinical status. Only one patient each in groups 1 and 2 was in AF 6 weeks after discharge. There was a trend toward a higher mortality and morbidity in group 2 patients. PAF after coronary surgery appears to be a self‐limited disease process. In this cohort of patients, the rate of recurrence of AF after discharge was similar in patients receiving class I or class III antiarrhythmic drugs together with rate control agents compared to those receiving rate control drugs alone.
Force and Torque Effects of a 1.5‐Tesla MRI Scanner on Cardiac Pacemakers and ICDs
Authors: LUECHINGER ROGER , DURU FIRAT , SCHEIDEGGER MARKUS B. , BOESIGER PETER , CANDINAS RETO
Published: July 2003

LUECHINGER, R., et al.: Force and Torque Effects of a 1.5‐Tesla MRI Scanner on Cardiac Pacemakers and ICDs. Magnetic resonance imaging (MRI) is a widely accepted tool for the diagnosis of a variety of disease states. However, the presence of an implanted pacemaker is considered to be a strict contraindication to MRI in a vast majority of centers due to safety concerns. In phantom studies, the authors investigated the force and torque effects of the static magnetic field of MRI on pacemakers and ICDs. Thirty‐one pacemakers (15 dual chamber and 16 single chamber units) from eight manufacturers and 13 ICDs from four manufacturers were exposed to the static magnetic field of a 1.5‐Tesla MRI scanner. Magnetic force and acceleration measurements were obtained quantitatively, and torque measurements were made qualitatively. For pacemakers, the measured magnetic force was in the range of 0.05–3.60 N. Pacemakers released after 1995 had low magnetic force values as compared to the older devices. For these devices, the measured acceleration was even lower than the gravity of the earth (< 9.81 N/kg). Likewise, the torque levels were significantly reduced in newer generation pacemakers (≤ 2 from a scale of 6). ICD devices, except for one recent model, showed higher force (1.03–5.85 N), acceleration 9.5–34.2 N/kg), and torque (5–6 out of 6) levels. In conclusion, modern pacemakers present no safety risk with respect to magnetic force and torque induced by the static magnetic field of a 1.5‐Tesla MRI scanner. However, ICD devices, despite considerable reduction in size and weight, may still pose problems due to strong magnetic force and torque.
Biventricular Pacing as Alternative Therapy for Dilated Cardiomyopathy Associated with Congenital Heart Disease
Authors: RODRÍGUEZ‐CRUZ EDWIN , KARPAWICH PETER P. , LIEBERMAN RANDY A. , TANTENGCO M. VICTORIA
Published: July 2003

RODRÍGUEZ‐CRUZ, E., et al.: Biventricular Pacing as Alternative Therapy for Dilated Cardiomyopathy Associated with Congenital Heart Disease. Biventricular, alternative, and multisite pacing are currently being explored to improve cardiac function among patients with medically refractory, end‐stage dilated cardiomyopathies. Although, due to inherent myocardial abnormalities, patients with repaired congenital heart defects may be at a greater risk than others to develop heart failure, often requiring cardiac transplantation. The efficacy of biventricular pacing among these patients is unknown. This report presents a patient with successfully repaired congenital heart disease in infancy who developed a symptomatic dilated cardiomyopathy at 22 years of age. Following biventricular pacing, systemic ventricular function showed a 14% improvement in ventricular dP/dt. One month later, subjective symptoms improved and cardiac ultrasound illustrated a 125% increase in fractional area of change. Exercise stress testing showed a 17% improvement in aerobic work capacity.
Inappropriate Shock Therapy in a Heart Failure Defibrillator
Authors: BETTS TIM R. , ALLEN STUART , ROBERTS PAUL R. , MORGAN JOHN M.
Published: July 2003

BETTS, T.R., et al.: Inappropriate Shock Therapy in a Heart Failure Defibrillator. A 63‐year‐old male with dilated cardiomyopathy underwent implantation of a “heart failure” defibrillator capable of biventricular pacing. He received an inappropriate shock 5 hours after the procedure. Stored electrograms revealed that during each sinus beat the ventricular channel recorded up to three separate events. These resulted from far‐field atrial sensing by the coronary venous lead, appropriate right ventricular sensing, then delayed left ventricular sensing (the result of left bundle branch block). As a consequence of far‐field left atrial sensing the two subsequent ventricular electrograms fell within the VF zone. Following an atrial premature beat, VF detection criteria were satisfied and shock therapy delivered. Although coronary venous lead repositioning eliminated far‐field atrial sensing, double counting of the widely split right and left ventricular electrograms still occurred during sinus rhythm. Shortening the programmed AV delay resulted in constant biventricular pacing with a single electrogram.
Unipolar Defibrillator?
Authors: PAVRI BEHZAD B. , HO REGINALD T. , PATEL VIKAS , CALLANS DAVID J. , FOLEY SHANE , KOCOVIC DUSAN Z.
Published: July 2003

PAVRI, B.B., et al.: Unipolar Defibrillator? An unusual case of “unipolar” pacing and myopotential oversensing leading to an inappropriate ICD shock in a patient with an implanted defibrillator is reported. The reasons for unipolar behavior in a system using a committed bipolar device are discussed.
Possible Role of Epicardial Left Ventricular Programmed Stimulation in Brugada Syndrome
Authors: CARLSSON JOERG , ERDOGAN ALI , SCHULTE BRITTA , NEUZNER JOERG , PITSCHNER HEINZ F.
Published: July 2003

CARLSSON, J., et al.: Possible Role of Epicardial Left Ventricular Programmed Stimulation in Brugada Syndrome. A patient with recurrent syncope due to polymorphic ventricular tachcardia was diagnosed with Brugada syndrome. Programmed right ventricular stimulation could not induce arrhythmia. Epicardial stimulation from a left ventricular site through the coronary sinus led to polymorhic VT. The stimulation protocol for risk stratification in Brugada syndrome is discussed.
Psychological and Physiological Factors Associated with Tilt Table Testing for Neurally Mediated Syncopal Syndromes
Authors: MCGRADY ANGELE , KERN‐BUELL CHERYL , BUSH ELLEN , KHUDER SADIK , GRUBB BLAIR P.
Published: July 2003

MCGRADY, A., et al.: Psychological and Physiological Factors Associated with Tilt Table Testing for Neurally Mediated Syncopal Syndromes. This study investigated psychological and physiological factors in two groups of patients who had tilt table testing for autonomic dysfunction. The first group of 61 patients completed assessments of depression, anxiety, and symptom effects on lifestyle. The 25 patients identified as tilt positive were younger (30.5 years) and had higher mean depression scores (7.6) compared to the tilt‐negative response group (n = 36); the latter averaged 40 years of age and had mean depression scores of 4.6. These differences were statistically significant. Women testing tilt positive were significantly more depressed than tilt‐negative women (P = 0.02). More severe depressive symptoms were associated with lower blood pressure (BP) (P < 0.05). A second group of 52 patients was monitored during tilt for BP, heart rate (HR), skin temperature (TEMP), skin conductance level (SCL), and forehead muscle tension (EMG). Twenty‐seven tested positive and 23 were negative. There were statistically significant group differences in systolic BP and diastolic BP (P < 0.05). There was a significant interaction between tilt status (positive or negative) and time (P = 0.03) in HR. TEMP increased 2 degrees over time in both groups (P < 0.05). The decrease in SCL from 13.7 to 10.4 μΩ in the tilt‐positive response group compared to the slight increase in the tilt‐negative group was significantly different (P < 0.05). Identification of psychological factors correlated with BP and physiological changes that accompany decreases in BP in tilt‐positive response patients could guide management of patients with autonomic dysfunction.
Laser Extraction of Entrapped Leads
Authors: PARSONNET VICTOR , ROELKE MARC , TRIVEDI ABHAY , RIZVI SYED A. , PERVEZ ARSHAD
Published: July 2003

Parsonnet, V., et al.: Laser Extraction of Entrapped Leads. Removing entrapped pacing and defibrillator leads has been greatly simplified by making use of the excimer laser extractor. Sixty‐two leads were successfully removed, although where appropriate, portions of the lead remained in place in 10 cases. There were two serious complications, one tear of the superior vena cava during an ICD extraction and one tear of the atrium during an atrial lead extraction. Both were controlled successfully through emergency sternotomy. Although extracting entrapped leads has been much simplified by making use of the laser extractor, the process is not free of serious complications. Those involved in explanting leads should be aware of the outcomes and be prepared for emergent management.
The Role of Purkinje and Pre‐Purkinje Potentials in the Reentrant Circuit of Verapamil‐Sensitive Idiopathic LV Tachycardia
Authors: AIBA TAKESHI , SUYAMA KAZUHIRO , AIHARA NAOHIKO , TAGUCHI ATSUSHI , SHIMIZU WATARU , KURITA TAKASHI , KAMAKURA SHIRO
Published: July 2003

AIBA, T., et al.: The Role of Purkinje and Pre‐Purkinje Potentials in the Reentrant Circuit of Verapamil‐Sensitive Idiopathic LV Tachycardia. Although the mechanism of verapamil‐sensitive idiopathic left ventricular tachycardia (ILVT) is usually reentry, the actual reentrant circuit is not clearly understood. This study examined the relationship between the Purkinje potential (PP) and a dull potential preceding PP (pre‐PP) during ILVT to elucidate the roles of these potentials in the reentrant circuit of ILVT. Electrophysiological studies and radiofrequency catheter ablation were performed in ten patients (7 men, 3 women, mean age 29 years) who had an ILVT with a right bundle branch block configuration and left‐axis deviation. Left ventricular endocardial mapping using an octapolar catheter and entrainment and resetting studies during VT was performed by pacing from the right ventricular outflow tract (RVOT) and each site of the left ventricular mapping catheter. PP and pre‐PP were recorded simultaneously during VT in all patients. The earliest PP during VT was recorded at the inferoposterior septum, and PP was activated bidirectionally toward the proximal (basal) and distal (apical) sites along the left posterior fascicle. In contrast, pre‐PP was recorded at sites slightly proximal to the earliest PP recording site, and was activated toward the earliest PP site. Pacing from RVOT confirmed manifest entrainment, and the stimulus to pre‐PP interval was prolonged with a shorter pacing cycle length. Concealed entrainment was demonstrated by capture of the PPs of the left ventricular mapping catheter in six patients, and the postpacing interval at each PP site was equal to the tachycardia cycle length. The pre‐PP was orthodromically activated from the proximal to the distal site during pacing. More rapid pacing also produced delay in activation from PP to pre‐PP, indicating slow conduction in ILVT. Catheter ablation was performed at the pre‐PP recording site during VT, and was successful in all patients. The reentrant circuit of ILVT could be constructed based on the pre‐PP, PP, and slow conduction between the PP and pre‐PP. Catheter ablation of ILVT was successful at the pre‐PP recording site.
The Impact of QT Lag Compensation on Dynamic Assessment of Ventricular Repolarization: Reproducibility and the Impact of Lead Selection
Authors: Lang Christopher C. E. , Flapan Andrew D. , Neilson James M. M.
Published: July 2003

LANG, C.C.E., et al.: The Impact of QT Lag Compensation on Dynamic Assessment of Ventricular Repolarization: Reproducibility And The Impact of Lead Selection. In cardiac disease, abnormalities exist in the rate‐corrected QT interval and the relationship between QT and heart rate. The QT/RR relationship is known to be dynamic and show circadian variation. The availability of automated methods for measurement of QT and RR intervals allows monitoring of the QT/RR relationship and may provide insights into arrhythmia onset. Using a method for analyzing 24‐hour recordings that incorporates beat‐by‐beat QT and RR measurement and an automated mechanism for compensating for lag in adaptation of QT to changes in RR, the authors evaluated the impact of lag compensation on assessment of the QT/RR relationship, reproducibility, and the effect of lead selection in 15 normal subjects. The QT/RR relationship is continuously estimated from the lag compensated data over a 5‐minute scrolling time frame. The relationship is expressed as an exponential formula, QT = QTo · RRJ where QTo is the QT interval at a standardized RR interval of 1 second and J is a variable exponent. We found that the use of lag compensation significantly improves the mean 24‐hour correlation between QT and RR data (r = 0.87 vs 0.65). The 24‐ hour mean of QTo and J were highly reproducible (coefficients of variation 2% and 8%, respectively). The mean 24‐hour QT/RR relationship for the population was QT = 0.415 · (RR)0.32. There was a small difference between leads in QTo and J. Compensating for QT adaptation lag provides a means of assessing the QT/RR relationship over long and short periods. This method allows investigation of the effect of acute interventions on the dynamic QT/RR relationship, which has previously been restricted by the presence of QT hysteresis.
Oozing from the Pericardium as an Etiology of Cardiac Tamponade Associated with Screw‐In Atrial Leads
Authors: AIZAWA KENICHI , KANEKO YOSHIAKI , YAMAGISHI TAKAHIRO , UTSUGI TOSHIHIRO , SUZUKI TORU , ISHIKAWA SUSUMU , OTAKI AKIO , MORISHITA YASUO , HASEGAWA AKIRA , KURABAYASHI MASAHIKO , NAGAI RYOZO
Published: July 2003

AIZAWA, K., et al.: Oozing from the Pericardium as an Etiology of Cardiac Temponade Associated with Screw‐In Atrial Leads. Screw‐in atrial pacing leads are widely used. Cardiac tamponade is a complication. An 81‐year‐old woman with advanced atrioventricular block underwent permanent pacemaker implantation and subsequently developed cardiac tamponade. At surgery, the lead‐tip screw was found penetrated through the right atrium but not through the pericardium. The source of bleeding was confirmed to scratching the inner pericardial membrane by the screw tip. Although cardiac tamponade due to perforation and leakage is known, tamponade caused by the trauma of an atrial screw on the pericardium with resultant ooze is less well described.