bluuebunny/crossref_metadata_2025 huggingface dataset:
Value of Serial Electropharmacological Testing in Managing Patients Resuscitated from Cardiac Arrest
Authors: RAVIELE ANTONIO , DI PEDE FRANCESCO , DELISE PIETRO , PICCOLO ELIGIO
Published: July 2006

Electrophysiologic studies were performed in 11 patients (9 men, 2 women; mean age: 59.9 yrs) who had survived an episode of cardiac arrest due to ventricular tarchycardia (VT) or ventricular fibrillation. The purpose of the studios was to evaluate the usefulness of serial acute drug testing in selecting an effective chronic antiarrhythmic regimen. Ten of the patients were suffering from chronic ischemic heart disease with one or more previous myocardial infarctions while one had no evidence of structural heart disease. A ventricular aneurysm was present in four of them. During control electrophysiologic study, a sustained VT was induced by ventricular stimulation (single and double extrastimuli at various paced ventricular cycle lengths plus bursts of rapid ventricular pacing) in nine of the ten patients (90%) who were studied while not receiving antiarrhythmic drugs; a non‐sustained VT was induced in one of them (10%). In three patients (30%) VT could be initialed only by right ventricular stimulation at a site different from the apex (outflow tract). No arrhythmia was observed in the only patient who was studied while taking amiodarone orally (400 mg/day for more than three months). During serial acute drug testing a totally effective drug regimen (successful in preventing the induction of any ventricular arrhythmia) was found in seven of ten patients (70%) who underwent this procedure and a partially effective drug regimen (a sustained VT was no longer inducible; it was easier to interrupt and it was considerably slower) was found in two patients (20%). None of the nine patients who received chronic antiarrhythmic therapy based on the results of serial acute drug testing died suddenly during a mean follow‐up of 14 months (range: 3–23) and only one had a recurrence of cardiac arrest. The latter, however, was taking antiarrhythmic drugs at a dosage less than that proved to be effective during electropharmacological testing. The only patient who refused serial acute drug testing and received an empiric antiarrhythmic therapy died suddenly at the 21st month of follow‐up. These results indicate that serial electropharmacological testing is useful in selecting an effective long‐term drug regimen in survivors of cardiac arrest.
The Clinical Incidence and Significance of Myopotential Sensing with Unipolar Pacemakers
Authors: FETTER JOSEPH , BOBELDYK GERARD L. , ENGMAN FRED J.
Published: July 2006

Myopotential oversensing by unipolar pulse generators can cause patient symptoms ranging from dizziness and syncope to ventricular tachycardia. Seventy‐seven patients with implanted unipolar pacemakers from three manufacturers participated in isometric and reach exercises to evaluate their pacemakers susceptibility to myopotentials. Myopotential inhibition occurred in 47% of the patients performing the reach maneuver. Testing revealed a wide difference in level of susceptibility to myopotentials between pacemakers of different manufacture (a low of 33% inhibition for the least susceptible to a high of 78% inhibition for the most susceptible during the reach maneuver). The normal pacing interval was extended by myopotential oversensing for each manufacturer's model within a range of 0.3–3.9 seconds. Pulse generators incorporating additional automatically‐adjusting threshold and reversion circuits in the sense amplifier along with standard bandpass filtering exhibited: a) two‐to‐three times less susceptibility to myopotentials; and b) a 75% reduction in the maximum pacing interval extension as compared with pacemakers with bandpass filtering alone. The effectiveness of insulative coating in reducing myopotential inhibition was substantiated as coated pulse generators had a 22% lower incidence of muscle sensing than those than were uncoated. Six out of seven patients tested had symptoms during Holter monitoring which correlated with pacemaker myopotential inhibition. Selecting pulse generators with improved sensing amplifiers, clinical testing of patients with unipolar pacemakers using the reach method, and reprogramming of sensitivity will significantly reduce the incidence of myopotential inhibition.
Emergency Guide Wire Pacing: New Methods for Rapid Conversion of a Cardiac Catheter into a Pacemaker
Authors: GESSMAN LAWRENCE J. , GALLAGHER JOHN D. , MacMILLAN ROBERT M. , MORSE DRYDEN , CLARK DONALD L. , MARANHAO VLADIR
Published: July 2006

We developed a new electrode to convert rapidly a previously inserted pulmonary artery or left ventricular catheter into a pacemaker. One method of doing this is by withdrawal of the pulmonary artery catheter from the pulmonary artery to the right ventricle by pressure control, and a Teflon‐coated guide wire, stripped of 5 mm of insulation at its tip, is advanced through the catheter to contact the endocardium. In the second method, the pacing electrode is advanced through the distal lumen of the catheter while it is positioned within the pulmonary artery and withdrawn into the right ventricle while pacing. Finally, a third Method involves advancement of the guide wire electrode into the left ventricle through a pigtail catheter. To pace, the guide wire electrode is connected to the cathode of a pacemaker referenced to a skin electrode. We paced 10 of 10 right heart cardiac catheterization, intra‐ and postoperative surgery patients by methods 1 and 2, and 4 of 4 left heart catheterization patients by method 3. Thresholds (mean ± SEM) for guide wire pacing were: right ventricle 1.52 ± 0.4 mA; left ventricle 1.33 ± 0.1 mA. Guide wire pacing is rapid, reliable, and requires little operator skill. Our indications for guide wire pacing are: 1) emergency right ventricular pacing in operative or intensive care unit patients with unexpected bradyarrhythmias who have an indwelling pulmonary artery catheter; and 2) emergency left ventricular pacing in left heart cardiac catheterization patients with contrast‐induced bradyarrhythmias.
Acceleration of Ventricular Tachycardia by Rapid Overdrive Pacing Combined with Extrastimuli
Authors: JENTZER JOHN H. , HOFFMANN ROBERT M.
Published: July 2006

A case of attempted termination of ventricular tachycardia using rapid overdrive pacing combined with double extrastimuli resulted in acceleration of the ventricular tachycardia. This case demonstrates the potential for acceleration of ventricular tachycardia when pacing termination is utilized.
Successful Treatment of Ventricular Tachycardia by Physiological Pacing
Authors: CRICK JONATHAN C.P. , WAY BERNARD , SOWTON EDGAR
Published: July 2006

The case is presented of a young patient with atrioventricular (AV) block but no evidence of other disease; in this patient exercise or stress‐related syncope continued after implantation of a ventricular inhibited (VVI) pacemaker. Investigation revealed exercise‐induced limited rapid multiform ventricular tachycardia (VT) which was associated with faintness or syncope. Temporary atrial triggered ventricular inhibited ventricular (VDD) pacing resulted in enhanced exercise tolerance with no significant arrhythmia. A permanent full function dual chamber [DDD] pacemaker was implanted and prevented the VT. There have been no further exercise‐related symptoms during two years 0f follow up.
Tracking of Atrial Flutter During DDD Pacing: Another Form of Pacemaker‐Mediated Tachycardia
Authors: GREENSPON ARNOLD J. , GREENBERG RICHARD M. , FRANKL WILLIAM S.
Published: July 2006

Two patients who had DDD pacemakers inserted for symptomatic sick, sinus syndrome developed sustained upper‐rate limit pacing. It was demonstrated in these two patients that pacemaker‐mediated tachycardia was due to tracking of atrial flutter. DDD pacemakers should be used with caution in patients with the sick sinus syndrome and associated atrial tachyarrhythmias. Medical treatment of recurrent atrial tachyarrhythmias may allow patients to remain in the DDD mode.
Patient‐Initiated Autonomous Pacemaker Tachycardia
Authors: SELTZER JEFFREY P. , LEVINE PAUL A. , WATSON WARREN S.
Published: July 2006

Multiparameter programmable DDD pacemakers are said to have an uncountable number of possible parameter combinations. It is probable that a number of these combinations, particularly when triggered by one or more critically timed native events, will result in bizarre and unanticipated rhythms sustained entirely within the timing circuit of the pulse generator. We report the occurrence and analysis of one such rhythm termed a sustained autonomous pacemaker tachycardia. In this rhythm, both atrial and ventricular outputs occur at the maximum tracking rate of the pacemaker with an apparently shortened AV interval. Once initiated, the ability to sustain the tachycardia requires that the maximum tracking rate interval exceed the atrial escape interval. It will then continue until the pulse generator is programmed to parameters that alter this critical timing or a properly timed ventricular sensed event occurs. It is anticipated that this will be only one of many similar rhythms encountered in patients treated with complex devices from all the manufacturers. In the future, once such a rhythm is noted and its mechanism identified, modifications of the basic circuit design will allow these parameters to be used without danger to the patient and without having to limit the options of the device.
Myopotential Interference Inducing Pacemaker Tachycardia in a DVI Programmed Pacemaker
Authors: van GELDER L.M. , EL GAMAL M.I.H.
Published: July 2006

A 67‐year‐old male, suffering from ventricular tachycardia unresponsive to drug therapy, received a universal AV sequential pacemaker (DDD,M). Tim pacemaker was programmed in the DVI mode, pacing role 100 bpm, AV interval 250 ms. After implantation, the patient experiences two episodes of tachycardia that proved to be pacemaker tachycardia with a rate of 150 bpm. The first period was self‐terminating, and the second had to be stopped by reprogramming the pulse generator. Pacemaker tachycardia could easily be provoked by instructing the patient to contract the pectoral muscle adjacent to the pulse generator. To our knowledge, this is the first report to pacemaker tachycardia provoked by myopotentials in a pulse generator programmed in the DVI mode.
Frequency and Significance of Left and Right Ventricular Late Potentials after Myocardial Infarction in Man
Authors: BETHGE CHRISTIAN , RECKER SIEGFRIED , GEBHARDT‐SEEHAUSEN URSULA , MÜLLGES W. , MERX WOLFGANG
Published: July 2006

Left and right heart catheterization was conducted on 45 patients with a history of myocardial infarction in order to detect so‐called ventricular late potentials by means of endocardiac mapping. The endocardiac signals were amplified 100 to 10,000 times at a low noise level using bipolar electrode catheters. The signals were stored unfiltered and visualized directly on an oscilloscope. Consistently recurring late potentials were recorded after QHS complexes in 32 patients (71%). They ranged in amplitude from 50 to 780 μV, while the coupling intervals were measured in the range of 80 to 620 ms from the beginning of the QRS complex to the beginning of the late potential. In some patients, the intracardially registered and/or Holter‐monitored ventricular ectopic beats occurred with a delay, corresponding to the delayed occurrence of the ventricular late potentials.
Extraction of an Intravascularized Pacemaker Lead—A New Approach to an Unusual Problem
Authors: SCHWARTZ ALAN B. , FUNG GORDON , LEWIS ARTHUR , HUNTER GLENN , VERLENDEN WILLIAM , KLAUSNER STEVEN C.
Published: July 2006

A new catheter approach to removing an intravuacularized, nonfunctional pacemaker lead which was fixed at both distal (right ventricular endocardium) and proximal (brachiocephalic vein/superior vena cava) ends is described. This case also emphasizes the need for removal of an old pacemaker lead that caused bacteremia in a patient with a prosthetic aortic valve even when infection was presumed to be cured.
Twiddler's Syndrome: A New Twist
Authors: VELTRI ENRICO P. , MOWER MORTON M. , REID PHILIP R.
Published: July 2006

Twiddler's syndrome, characterized by dislodgment of pacemaker leads due to twisting of pulse generalors within the subcutaneous pocket with subsequent retraction of leads and loss of pacing function, has been well described in patients with permanent pacemakers implanted for bradyarrhythmias. The case presented here is the first report of a patient with an internal automatic cardioverter‐defibrillator with lead dislodgment due to pulse generator rotation. This case exemplifies a new subset of patients prone to the Twiddler's syndrome.
Ten‐year Follow‐up on 1,000 Patients with Transvenous Electrodes
Authors: LAGERGREN HANS , LEVANDER‐LINDGREN MAJ
Published: July 2006

One thousand patients given a transvenous electrode EMT 588 until mid‐January, 1974, were followed up for a minimum of 10 year. Two hundred ninety‐six patients survived this time or longer. Fully 30% of them were above the age of 70 when first paced. During the observation period, 34% of the survivors had electrode complications requiring electrode replacement. These occurred in almost 14% during the first year of treatment. Electrode failures during the first year were due mainly to dislocations and rises in the stimulation threshold, while later failures were caused chiefly by damage to the lead, which was caused, in part, by repeated pulse generator replacements and infections. Half of the patients who survived for more than 15 years have the original electrode, the oldest one now exceeding 22 years.
Tachycardias Initiated by Automatic Antitachycardia Pacemakers
Authors: FÅHRAEUS THOMAS , LASSVIK CLAES , SONNHAG CHRISTINE
Published: July 2006

Available automatic tachycardia‐terminating pacemaker cannot distinguish between physiological and pathological tachycardia and, consequently, electrical stimulation during sinus tachycardia can occur. In order to evaluate whether this might be an arrhythmogenic problem or not the cardiac response in eight patients having paroxysmal supraventricular tachycardia treated with tachycardia‐terminating pacemakers was studied during exercise. After tachycardia recognition, the implanted pulse generator automatically emits single or double critically timed premature stimuli for termination of the arrhythmia. Post‐implantation examination revealed successful tachycardia termination by the pacemaker at rest, without the addition of any antiarrhythmic drugs, in all eight patients. During exercise tests, the sinus rate in seven patients exceeded the programmed tachycardia trigger rate resulting in triggered pacemaker stimulation. The native supraventricular tachycardia was initialed in four cases. In one of these patients, two short episodes of probable ventricular tachycardia were also recorded. This study demonstrates the clinical value of post‐implantation assessments with exercise tests concerning the problem of pacemaker‐initiated tachyarrhythmias. Tachycardia‐terminating devices can induce tachycardias, and individual precautions must be taken in order to prevent or minimize the risk of pacemaker reversion of sinus rhythm to paroxysmal tachycardia or hazardous arrhythmias.
Effect of Amiodarone on Electric Induction, Morphology, and Rate of Ventricular Tachycardia and its Relation to Clinical Efficacy
Authors: REDDY C. PRATAP , KUO CHIEN SUU , JIVRAJKA VINOD
Published: July 2006

Using His bundle electrograms and programmed ventricular stimulation, the effects of chronic amiodarone treatment on induction, morphology, and the rate of ventricular tachycardia (VT) were studied in 17 consecutive patients treated with amiodarone for control of recurrent sustained VT or ventricular fibrilation. Studies were done before and after treatment with amiodarone for an average duration of 5.3 (range 2 to 18) months. During the control study, sustained VT could be induced in 16 patients. VT was initiated by single or double right ventricular (RV) extrastimuli in 14 patients, by double left ventricular (LV) extrastimuli in 1 patient, and by RV burst pacing in 1 patient. Only one pattern (morphology) of VT similar to that of spontaneous VT was induced in 12 patients and two patterns of VT in 4 patients. The average cycle length (CL) (mean ± SD) of induced VT was 325.8 ± 61.2 ms. After amiodarone, VT could be induced in 7 of 17 patients and was initiated by single RV extrastimuli in 5 patients, double RV extrastimuli in 1 patient, and RV burst pacing in 1 patient. In 3 of 5 patients in whom VT could be initiated by single RV extrastimuli, initiation of VT required double RV or double LV extrastimuli in the control study; in 1 of 5 patients VT could not be induced in the control study. Amiodarone induced nonclinical, polymorphic VT in 4 patients in whom only clinical VT could be induced during the control study. Compared to control, the CL of induced VT was significantly longer (322 ± 65.7 vs 416 ± 41.5 ms; P < 0.001). During a follow‐up period ranging from 4 to 53 (mean ± SD; 18.6 ± 11.4) months, VT did not recur in 8 patients with no inducible VT and in 6 patients with persistence of inducible VT. One patient without inducible VT died suddenly; VT recurred in 2 patients, one without inducible VT and one with inducible VT. The results show that programmed stimulation studies late in the course of treatment do not accurately reflect the clinical efficacy of amiodarone in VT.
Noninvasive Detection of Insulation Break
Authors: FEREK BOŽIDAR , PASINI MIRAM , PUSTIŠEK STJEPAN , JURŠIĆ MARIJAN , TONKOVIĆ STANKO
Published: July 2006

This study describes a method of leak detection. The underdrive inhibition test—chest wall stimulation with external stimulator (ES)—was used for this purpose. Three cutaneous electrodes (CE) were applied: the first one above the indifferent electrode, the second one above the suspected leak location, and the third one above the active electrode. Two inhibition thresholds (IT) were measured: the first one connecting ES on first CE and second CE, and the second one connecting ES on first CE and third CE. The inhibition threshold is the value of ES output charge at which the inhibition of implanted pacemaker occurs. The relation between two Its, not the absolute value, is significant for leak estimation. The former should be at least five times higher than the latter, if there is no current leak. During the two years of follow‐up of 541 patients, 272 measurements were performed. In 52 cases the connector leak was found‐both ITs were approximately equal. Twenty‐seven cases were confirmed by surgery for EOL pacemaker replacement; the intrusion of body fluid was evident. Five operations were indicated because of the leak problem: two ‐ muscle twitching, one ‐ loss of capture, one ‐ undersensing, and one ‐ insulation break with lead fracture. The method, although approximate, is a reliable qualitative estimation of leak.
Standard Diagnostic Programmed Electrical Stimulation Protocols in Patients with Paroxysmal Recurrent Tachycardias
Authors: BRUGADA PEDRO , WELLENS HEIN J.J.
Published: July 2006

La Stimulation programée manque une certaine standardisation en ce qui concerne son rôle diagnostique et thérapeutique en matière d'arythmies. Si la sensibilityé et la spécificité de ces tests doivent être considérées comme valables, l'evaluation de divers protocoles de stimulation est obligatoire. Les variables sont nombreuses et peuvent influencer les résultats de ces études.
Pacemaker Syndrome with DDD Pacing
Authors: TORRESANI J. , EBAGOSTI A. , ALLARD‐LATOUR G.
Published: July 2006

La stimulation DDD peut entrainer certains in‐convénients semblables à ceux du “Pacemaker Syndrome.” Des tachycardies électroniques liées au boitier peuvent survenir si la conduction rétrograde VA est présente, ce en l'absence de dysfonctionnement du pacemaker. Ce problème peut être corrigé par reprogrammation dans la plupart des cas. En outre certains phénomènes liés au temps de conduction intra‐auriculaire et au délai AV optimal sont discutés.
Ideal Atrial Lead Positioning to Detect Retrograde Atrial Depolarization by Digitization and Slope Analysis of the Atrial Electrogram
Authors: WAINWRIGHT RAY , DAVIES WYN , TOOLEY MARK
Published: July 2006

Chez 10 patients à conduction rétrograde ventriculo‐auriculaire (V‐A) intacte (temps de conduction VA moyen = 296 +/‐ 45 ms) ont été enregistrés simultanément des électrogrammes bipolaires en 3 sites auriculaires différents: oreillette droite haute (HRA), oreillette droite basse (LRA) et auricule droit (RAA) en cours de rythme sinusal (électrogramme antérograde) et pendant la stimulation ventriculaire (électrogramme rétrograde) les auriculogrammes ont été digitalisés et analysés à l'aide d'un programme spécial de détection des événements. Chez tous les patients il a été possible de distinguer le caractère antérograde ou rétrograde de l'auriculogramme à partir d'un ou 2 sites d'enregistrement. La reconnaissance digitale du signal était entièrement automatique et pourrait être utilisée dans la prévention des tachycardies liées au pacemaker, en l'incorporant dans les futurs générateurs utilisant des microprocesseurs.
Programmability in DDD Pacing
Authors: BAROLD S. SERGE , FALKOFF MICHAEL D. , ONG LING S. , HEINLE ROBERT A.
Published: July 2006

Des pacemakers DDD fiables, non dangereux ayant de nom‐breuses possibilités de programmation sont maintenant au point. Certains paramètres programmables tels que mode, voltage (courant), largeur d'impuision, sensitivité et périodes réfractaires, dans chaque chambre sont fondamentaux. La fréquence maximum limite de même que ies donnees lors des rythmes Ients et les intervalles AV sont également iniportants. Avec certains modèles, la possibilité de programmer Ja période de blanking s'est montrée très utile. La corrélation de toutes ces fonctions assure Je fonc‐tionnement sans fautes de ces appareiJs.
The Marker Channel: A Telemetric Diagnostic Aid
Authors: DUFFIN EDWIN G.
Published: July 2006

Vinterprétation des tracés ECG des patients porteurs de pacemakers sophistiqués est souvent difficile. De ce fait de tels pacemakers sont maintenant équipés de télémétrie restituant les données programmées. L'utiJisation d'un canal marqueur, les intervalles de détection, et de stimulation est particuliérement utile en ce sens, Il est ainsi possible d'obtenir un inventaire détaillé des événements en association à l'ECG en queiques minutes, et d'une précision telle qu'il n'est plus nécessaire à l'operateur de mémoriser les données du pacemaker. Le système est décrit, et quelques exemples sont discutés.
Clinical Benefits of Telemetered Electrograms in Assessment of DDD Function
Authors: LEVINE PAUL A. , SHOLDER JASON , DUNCAN JAMES L.
Published: July 2006

La télémétrie de l'ECG endocavitaire est une nouvelle téchnique pour la stimulation DDD. L'expérience initiale confirme que les données transmises par cette méthode sont comparables à celles que Ton pouvait avoir seuiement par des techniques invasives. La valeur de cette technologie est mise en évidence dans cette présentation. A notre avis elle va continuer à prendre de l'importance au fur et à mesure que les stimulateurs sophistiqués prolifèrerant.
Bipolar versus Unipolar Issues in DDD Pacing
Authors: BAKER ROSS G. , FALKENBERG ERIC N.
Published: July 2006

Les mérites relatifs de la stimulation unipolaire et bipulaire sont discutés dans le contexte des stimulateurs DDD. Pour assurer le recueil du potentiel auricuiaire en présence de potentiel musculaire, l'utilisation d'un systéme bipolaire est préferable. Le recueil bipolaire ventriculaire réduira l'incidence d'inhibition par des myopotentiels et pourrait aussi réduire la possibilité de l'écoute croisée. Cependant, la stimulation est mieux obtenue par un systéme unipolaire. C'est pourquoi nous développons un nouveau stimulates qui fournira la slimulation en unipolaire et le recueil du potentiel en bipolaire. Ce stimulateur est conçu et basé sur un schéma unipolaire, avec la simplicité et la fiabilité inhéreutes à ce mode.
Advantages and Disadvantages of Various Upper and Lower Rate Responses
Authors: JACOBSON P. , RIPART A.
Published: July 2006

Les avantages et les inconvénients de plusieurs types de réponses aux fréquences maximales et minimales sont présentés. La réponse idéaie dépend des paramétres programmés ainsi que le rapport avec les cycles cardiaques naturels. Le stimulateur physiologique idéal fournira plusieurs choix différents pour la réponse à une fréquence donnée. En plus, il fournira au médecin les moyens de vérifier les effets physiologiques de telle ou telle réponse.
Follow‐Up of DDD Pacemakers
Authors: LUCERI RICHARD M. , HAYES DAVID L.
Published: July 2006

La surveillance des pacemakers DDD est devenue de plus en plus difficile à cause de la complexitSeA croissante des générateurs d'impulsion. Un “test type” devrait être développé pour permettre une analyse systematique et l'enrégistrement des données. Pour suivre efficacement un patient porteur d'un pacemaker DDD il est nécessaire de connaître son rythme sousjacent celeri du générateur d'impulsion, la souplesse de sa programmation et ses autres particularités.
Simultaneous Atrial and Ventricular Electrogram Transmission Via a Specialized Single Lead System
Authors: HUGHES HOWARD C. , FURMAN SEYMOUR , BROWNLEE ROBERT R. , DELMARCO CHARLES
Published: July 2006

Aucun stimulateur à télémétrie n'est capable de détecter et transmettre l'éctrogramme (EGM) pendant le rythme normal ou stimulé. Certains peuvent détecter et transmettre soit l'onde P, soit l'onde R. Une nouvelie électrode reliée à un nouveau stimulateur à télémétrie a été dévelopée. Elle permet la transmission de l'EGM complet sans être affecté ni par le courant du stimulateur, ni par les postpotentiels. Les électrodes sont placées dans l'oreillette et le ventricule droit pour optimiser la détection. Ces électrodes sont séparées électriquement des électrodes de stimulation et de recueil du potentiel. Cependant elle font partie d'une électrode ventriculaire coaxiale qui n'est pas plus large qu'une électrode bipolaire normale (2,3 mm). Le systéme de telémétrie est compatible avec le monitoring par téléphone. Ce système a pu démontrer sa capacité pour la détection correcte de l'EGM pendant le rythme sinusal normal et n'affecte pas la stimulation auriculaire, ventriculaire ou AV séquentielle. De plus, il détecte et transmet des anomalies telies que des extrasystoles, la conduction rétrograde et des modifications ischémiques. Les électrodes de ce type liées à des stimulateurs VVI avec télémétrie ont été implantées chez des chiens durent plus de 2 ans. Ce systéme fournira les moyens de détecter de façon non‐invasive et d'enregistrer par télemétrie l'EGM normal et anormal en entier, même chez les patients qui dependent de leur stimulateur.
How Should the Software Pacemaker Be Programmed During Manufacturing and after Implantation?
Authors: RIPART A. , FONTAINE G. , MUGICA J.
Published: July 2006

Les différentes possibilités pour programmer les stimulateurs sont présentées. Un stimulateur à base “hardware” fournit une stimulation bien fiable mais avec des limites étroites. De l'autre côté, un stimulateur logiciel (à“software”) aurait une flexibilité maximale en ceoui concerne les programmes, mais restera plus susceptible d'erreurs de software. La solution mediane diviserait le programme entre mémoire ROM passive et mémoire RAM active. Cette alternative pourrait fournir une réponse sophistiquée sans sacrifier la sécurité du système.
The Importance of Software Programmable Pacemakers: In Vivo Programming of a Prototype Device
Authors: WITTKAMPF F.H.M. , CANDELON B. , Van ARRAGO G.W.
Published: July 2006

Nous avons récemment développé des stimulateurs à base de microprocesseur avec flexibilityé reélle du software. Les 25 premiers appareils implantés (type DPG‐1) ont démontré un phénomène inattendu suite à une erreur du microprocesseur. Un système de securityé a annullé toutes les fonctions spéciales et a remis tous les parametres aux paramètres “standards.” Le problème a été résolu par la modification noninvasive du software. Plus de 200 stimulateurs (type TX‐1) qui fournissent un rythme asservi aux variations de l'espace QT, ont été impiantés jusqu'en mai 84. Ces stimulateurs étaient construits avec les mêmes circuits microéléctroniques que ceux du type DPG 1. Les connaissances obtenues au cours des essais cliniques étaient directement appliquées non seulement aux nouveaux implants mais aussi aux anciens implants. Ceci a étééffectué par la reprogrammation du software dans Jes slimulateurs implantés.
Pacemaker Architecture: A Pacemaker with an Attached Computer or a Computer with an Attached Pacemaker
Authors: SEGERSTAD CHRISTER HÅRD AF , LEKHOLM ANDERS , ELMQVIST HÅKAN
Published: July 2006

Les microprocesseurs ont une importance majeure dans la téchnologie des stimulateurs cardiaques. Le développement de systèmes adaptatifs capables de répondre aux variables physiologiques va au bout du compte améliorer les qualityés des soins prodigués à chaque patient. Quoi qu'il en soit et dans le but de minimiser la consommation d'énéergie, il sera nécessaire d'incorporer certaines fonctions dans le boitier, en dehors du microprocesseur. Un langage spécifique supplémentaire peut, de plus, devenir nécessaire.
The Role of the Computer in Cardiac Pacemaker Technology
Authors: BENEDEK Z. MICHAEL , FURMAN SEYMOUR
Published: July 2006

Afin d'améliorer la performance et de réduire la taille des stimulateurs, on utilise les technologies les plus modernes. Le haut niveau technologique du stimulateur necéssite un niveau encore plus haut pour les systèmes de surveillance. Les méthodes actuelles qui comportent des programmeurs individuels pour chaque modèle de stimulateur mènent à la confusion et sont inadéquates. La solution développée à J'hôpital Montefiore consiste en un programme à trois étapes; 1) un programme informatique qui guide le personnel; 2) un programme informatique qui permet d'envoyer les mêmes commandes aux divers programmeurs et de faire I'identification des divers modèles de stimulateurs; 3) un programme interne où les tests et la surveillance proviennent du software interne. Le système utilise la version MIIS du langage MUMPS mais a subi des modications importantes pour faire la conversion d'un langage à l'autre.
Data Storage and Retrieval by Implantable Pacemakers for Diagnostic Purposes
Authors: SANDERS RICHARD , MARTIN RICHARD , FRUMIN HOWARD , GOLDBERG MARK J.
Published: July 2006

Les microprocesseurs sont à la base de plusieurs fonctions existant dans les stimulateurs à double chambre. Le recueil des donnèes par un système logiciel permet J'échange facile de ces informations par télémétrie. Ces systèmes sont limités par la quantité et la qualityé des données, le type de logiciel utilisé, et la quantité de mémoire RAM disponible. Les données ainsi obtenues sont utiles pour suivre un patient non seulement en matière de stimulation mais aussi pour réglage de la thérapeutique medicamenteuse, etc. II est possible qu'avec cette technologie, d'autres méthodes d'enregistrement auront moins de valeur (par exemple le monitoring Holter) pour certains patients.
Increasing Cardiac Rate by Measurement of Right Ventricular Temperature
Authors: FEARNOT NEAL E. , JOLGREN DAVID L. , TACKER WILLIS A. , NELSON JAMES P. , GEDDES LESLIE A.
Published: July 2006

Un stimulateur qui augments sa Fréquence en fonction de l'exercice permet au patient d'améliorer son état de bien‐être. Les capteurs pourraient utiliser la fréquence auriculaire, l'espace QT, le pH, la saturation d'oxygène du sang veineux, la fréquence ventilatoire, le débit cardiaque, les mouvements du corps et la température sanguine. Afin de déterminer l'éfficacité de la reconnaissance de l'exercice par utilisant la température du sang du ventricule droit, un stimulateur expérimental a été développé et évalué chez le chien. Un algorithme a été incorporé dans un stimulateur VVI comportant un microprocesseur, qui pourrait détecter l'exercice et le repos à partir de la température sanguine Deux fréquences de stimulation étaient done possibles pour améliorer le débit cardiaque. Des etudes sont en cours peur démontrer la fisabilité d'un tel systéme chez l'homme.
Increasing Cardiac Rate by Tracking the Respiratory Rate
Authors: ROSSI PAOLO , AINA FRANCO , ROGNONI GIORGIO , OCCHETTA ERALDO , PLICCHI GIANNI , PRANDO MARIA DOMENICA
Published: July 2006

Un stimulateur asservi qui utilise la fréquence venlilatoire comme capteur a été implunté chez 22 patients, dont 19 pour la stimulation ventriculaire et 3 pour la stimulation auriculaire. Le niveau d'exercice atteint en utilisant ce système a été toiijours supérieur à celui de la stimulation ventriculaire à fréquence fixe. En plus, aucun capteur chimique ou mécanique n'était utilisé; le capteur même est simple, durable et utilise une faible énérgie. Done, ce système s'adapte facilement à chaque patient individuel.
Regulation of Pacing Rate by Variations of Mixed Venous Oxygen Saturation
Authors: WIRTZFELD A. , HEINZE R. , STANZL K. , HOEKSTEIN K. , ALT E. , LIESS H.D.
Published: July 2006

La saturation d'oxygene du sang du ventricule droit (So2) serait un capteur idéal pour asservir la fréquence d'un stimulateur implanté. Afin de prouver cette hypothèse, des inesures de So2 au repos et à l'éxercice ont été réalisées chez des sujets normaux et chez des patients porteurs de stimulateurs; ensuite un algorithme a été développé pour faire varier la fréquence de stimulation en fonction de la So2 mesurée. Les résultats suggèrent que cette méthode pourrait être utile aux implants à long terme.
Clinical Experience with Implantable Scanning Tachycardia Reversion Pacemakers
Authors: SPURRELL ROWORTH A.J. , NATHAN ANTHONY W. , CAMM A JOHN
Published: July 2006

Un stimu‐lateur implantable et automatique de type scanning a été développé et utilisé pour l'intérruption des tachycardies chez l'homme. Depuis janvier 1982, 22 patients ont reçu ce stimulateur à St. Bartholomew's Hospital. Plus de 125 appareils ont été implantés au total dans le monde. Les résultats cliniques sont encourageants, surtout avec la deuxième géneration de stimulateurs.
Discrimination of Supraventricular Tachycardia from Sinus Tachycardia of Overlapping Cycle Length
Authors: PLESS BENJAMIN D. , SWEENEY MICHAEL B.
Published: July 2006

Depuis plus de 35 ans, des stimulateurs ont été impiantés pour le traitement des tachycardies. Les systèmes non‐automatiques ne sont pas utitisés d'une façon générale parce qu'ils necéssitent une participation directe de la part des patients. Les systèmes automatiques ont été limités par le manque de flexibilityé des paramètres programmables et par leur incapacityé de distinguer les tachycardies sinusales des tachycardies pouvant étre interrompues par la stimulation. De nouveaux algorithmes permettant de faire cette différentiation commencent a être disponibles. En plus des critères de détection qui utilisent la fréquence, il y a trois autres critères qui puissent caractériser les tachycardies: (1) le début brusque; (2) la stabilityé de la fréquence; (3) une fréquence élevée soutenue. Des futurs stimulateurs antitachycardie seront capables d'employer des algorithmes encore plus élaborés dès que des microprocesseurs et des capteurs plus sophistiqués seront disponibles.
Preliminary Experience with the Implantable Transvenous Cardioverter
Authors: ZIPES DOUGLAS P. , HEGER JAMES J. , MILES WILLIAM M. , PRYSTOWSKY ERIC N.
Published: July 2006

Un choc synchronisé d'énergie inférieure à 2 joules délivréà travers un catheter spécialement conçu à cet effet peut terminer une tachycardie ventriculaire soutenue chez le chien et l'homme. Une telle fonction est programée dans un boitier de 95 grammes, impianté sous anesthésie locale à la xylocaine, capable par ailleurs de stimulation VVI et d'effectuer des études éléctrophysiologiques. Sept patients ont reçu ce boitier et J'expérience initiale est rapportée.
Unipolar Electrode System for an Implantable Defibrillator: New Experimental Approaches
Authors: FONTAINE G. , CANSELL A. , LECHAT Ph. , PAVIE A. , GROSGOGEAT Y.
Published: July 2006

Chez le chien normal nous avons étudié le seuil de défibrillation après induction de fibrillation ventriculaire par un courant alternatif. Après une période de fibrillation soutenue de 10 secondes, des chocs d'énérgie progressivement croissante sont delivrés. Le systèeme d'éléctrode endocavitaire est capable d'une configuration unipolaire ou bipolaire; l'électrode distale se situe è l'apex du ventricule droit. Les résultats suggèrent que pour une capacité optimale de 9‐20 uF, les chocs unipolaires (3‐10j) sont plus éfficaces que les chocs bipolaires (10‐30j). En plus, des arrythmies diverses telles que la tachycardie ventriculaire rapide, le rythme idioventriculaire accéleré et le bloc AV transitoire sont frequemment observées. Nous concluons que: (1) un défibrillateur endocardique unipolaire et implantable semble faisable; (2) il devrait incorporer des circuits appropriés pour le traitement des arrythmies observées après choc.
Surgical Techniques for Implanting the Automatic Implantable Defibrillator
Authors: WATKINS LEVI , MOWER MORTON M. , REID PHILIP R. , PLATIA EDWARD V. , GRIFFITH LAWRENCE S.C. , MIROWSKI M.
Published: July 2006

Depuis février 1980, le défibrillateur automatique a été implanté chez 77 patients ayant survécus à plusieurs arrêts cardiaques. La voie souscostale a été utilisée chez 28 patients, et la tharocotomie chez 20 patients. Dans 29 cas, une sternotomie médiane a été utilisée en raison d'autres interventions chirurgicales cardiaques antérieures. Bien que la voie sous costale paraîsse la plus bénigne, toutes ces téchniques sont éfficaces. La méthode préferée est déterminée par l'aspect clinique. Les statistiques démontrent une survie nettement améliorée chez tous ces patients à haut risque.
A Solution to Difficult Power Frequency Interference on ECG Recordings
Authors: BOYD EDWARD GEORGE CHARLES ARTHUR
Published: July 2006

Line, or 50 Hz, interference is a common feature of ECG recordings where either the instrument performance is unsatisfactory or the tissue electrode preparation is inadequate. With the superior performance of modern ECG machines, the electrode preparation required is minimal. Any interference present on the recording can usually be eliminated by a reapplication of the electrodes. Where it is persistent, this may be due to a magnetic field interacling with the loop formed by the electrode leads and the subject. Reducing the loop area by repositioning the electrode leads will usually produce a clear recording. A particular area in an ECG department, designated for routine ECG recordings, produced tracings contaminated with over 0.4 mV peak to peak of interference despite all efforts to eliminate it. After investigation, a novel solution was developed which actively reduces the environmental power line magnetic field. Three adjacent examination couches have been treated and are now satisfactory for routine ECG determinations with no noticeable interference.
Myopotential Inhibition of Unipolar Pacing in Children
Authors: MICHALIK RICHARD E. , WILLIAMS WILLIS H. , HATCHER CHARLES R.
Published: July 2006

Myopotential inhibition of unipolar demand pacing systems has been shown to be a frequent occurrence in adults with transvenous pacing systems in which the pulse generators are implanted adjacent to the pectoralis muscle. To evaluate this problem in children, most of whom have epimyocardiol systems and abdominal wall generator implants, 50 patients underwent electrocardiographically monitored exercise nnd 24‐hour ambulatory electrocardiograph monitoring. Patients' ages at the time of study ranged from less than one year to 18 years, and weights ranged from less than 5 kg to 63 kg. Sixteen different models of pulse generators from five manufacturers were involved. Pacing modes were VVI. DVI. AAI, VDD, and DDD. Forty‐seven patients had epimyocardial systems. None of the patients was symptomatic as a result of myopotential inhibition. Oniy three patients (6%) had any evidence of myopotential inhibition and all three demonstrated this inhibition on both monitored exercise and ambulatory electrocardiograph. The inhibition was eliminated by reprogramming the sensitivity levels of the three generators without compromising R‐wave sensing. Thirteen of the remaining 35 patients with mulliprogrammable generators had induction of myopotential inhibition when exercised after temporary programming to maximal sensitivity settings. Myopotential inhibition of unipolar demand pacing appears to be less frequent and less problematic in the pediatric population, even though they are physically quite active. It is not clear whether this is a function of patient size or the abdominal wall position of the pulse generator. Because our three cases of pacing inhibition occurred in larger children, we currently recommend repeated testing for myopotential inhibition as the patients continue to grow.
Long‐term Management of Recurrent Paroxysmal Tachycardia by Cardiac Burst Pacing
Authors: PETERS ROBERT W. , SCHEINMAN MELVIN M. , MORADY FRED , JACOBSON LESTER
Published: July 2006

Sixteen patients with either recurrent symptomatic supraventricular tachycardia (SVT) (ten) or ventricular tachycardia (VT) (six) unresponsive to drug treatment underwent insertion of chronic overdrive cardiac pacing devices for arrhythmia control. All patients with SVT followed for longer than 2.5 years required concomitant drug therapy for rhythm control. In addition, one of the ten patients required amiodarone and three required nonpharmacologic therapy (catheter ablation of the atrioventricular junction (one), surgical ablation of the Kent bundle and/or bundle of His (two). In the six patients with VT, only one patient used the device successfully. In the other five patients, either the arrhythmia failed to respond to burst overdrive pacing (three) or overdrive acceleration resulted (two). One death in the latter group was related to induction of rapid VT followed by ventricular fibrillation. Long‐term follow‐up of patients with paroxysmal SVT shows that virtually all require concomitant drug therapy and may require aggressive medical or surgical procedures for arrhythmia control. Use of ventricular overdrive pacing for those with VT appeared singularly disappointing in that pacing proved either ineffective (three) or resulted in overdrive acceleration (two) in 5/6 patients.
Reversion Mode Activation by Myopotential Sensing in a Ventricular Inhibited Demand Pacemaker
Authors: ERKKILA KEVIN I. , SINGH JANG B.
Published: July 2006

Pacemaker follow‐up in a 72‐year‐old woman revealed occasional failure to sense and pace, which was confirmed by Holter monitor. Neither reprogramming the pacemaker sensitivity nor repositioning the lead resolved the problem. A recheck of the Holter recordings revealed pacing and sensing failures were concurrent with “baseline artifact,” suggestive of myopotentials. Furthermore, the inappropriate pacing spikes occurred at a rate of 90 pulses per minute (ppm). It was theorized that myopotential sensing was alternately inhibiting the pacer and activating the reversion mode, an asynchronous rate of 90 ppm. Reprogramming the unit to a lower sensitivity restored normal pacer function.
Control of Refractory Supraventricular Arrhythmias After Unsuccessful Closed‐Chest His Bundle Ablation
Authors: JOHNS JENNIFER A. , BLACK ALEXANDER J. , HARPER RICHARD W. , ROSENEELDT FRANKLIN , MIDDLEBROOK KENNETH , ANDERSON STANLEY T. , FEDERMAN JACOB , PITT AUBREY
Published: July 2006

Six palients underwent attempted catheter ablation of the His bundle for control of refractory supraventricular tachyarrhythmias. Permanent complete heart block was achieved in only three patients. All six patients have remained asymptomatic withoul anfiarrhythmic medicolions over a follow‐up period of six to 17 months (mean 10 months). There were no complicalions of the procedure apart from mild elevation of creatine kinase levels in three patients. In this series, resumption of atrioventrcular (AV) conduction following attempted His bundle ablation was not associated with recurrence of symptomatic arrhythmias. Preservation of AV conduction may also obviate the need for permanent ventricular pacing.
Automatic Scanning Extrastimulus Pacemaker to Treat Ventricular Tachycardia*
Authors: HIGGINS JAMES R. , SWARTZ JOHN F. , DEHMER GREGORY J. , BEDDINGFIELD GEORGE W.
Published: July 2006

Many investigators have reported the use of various permanent pacemaking modes in the long‐term management of patients with recurrent ventricular tachycardia.1–9 The three general types of antitachycardic pacemakers are; (1) underdrive; (2) burst; and (3) scanning pacemakers, Such devices have been activated externally or have had automatic activation. Each antitachycardic pacemaking modality has known technical and physiologic limitations. A serious limitation of dual‐demand underdrive pacemakers is that they are usually successful only for tachycardias with a rate below 160 bpm becsuse a random stimulus is needed for conversion.7 Therefore, this modality is seldom useful in patients with symptomatic sustained ventricular tachycardia in which rates are generally greater than 160 bpm and/ or hemodynamic compromise occurs rapidly. Although others have reported the successful use of burst pacemakers in the control of ventricular tachycardia, this technique may cause acceleration of ventricular tachycardia and induction of ventricular fibrillation.1.3.5–9 Programmable automatic scanning pacemakers have been used successfully to treat paroxysmal supraventricular tachycardia10 and have been used recently in combination with antiarrhythmic agents to control ventricular tachycardia.11 This report outlines the use of an automatic scanning pacemaker alone for the treatment of symptomatic ventricular tachycardia in a patient who was unable to tolerate conventional antiarrhythmic medications.
Subcostal M‐Mode Echocardiography of the Right Atrial Wall in Evaluation of Cardiac Arrhythmias and Pacing
Authors: DRINKOVIC NIKŠA , FEREK BOŽIDAR , JURS̄IC MARIJAN
Published: July 2006

Subcostal M‐mode echocardiography of the right atrial wall in combinalion with the sitmultaneously recorded nondiagnostic electrocardiogram is useful in the recognition of various rhythm disturbances. Each arrhy thmia has a characteristic right atrial wall motion pattern. Flat and hidden P‐waves can be accurately detected throughout the cardiac cycle and supraventriculur tachycardias with aberration can be distinguished from ventricular tachycardia with AV dissociation. This echocardiographic technique is of special value in the follow‐up of physiological pacemakers because atrial capture and sensing malfunctions can he reliably detected. Finally, it can also facilitate the programming of atrial channels output + sensitivity, and recognition of the pacemaker syndrome.
Ventriculoatrial Conduction: A Cause of Atrial Malpacing in AV Universal Pacemakers. A Report of Two Cases
Authors: van GELDER L.M. , EL GAMAL M.I.H.
Published: July 2006

Retrograde atrial activation during ventricular pacing has often been a cause of intermittent or persistent arrhythmias (pacemaker‐mediated tachycardia) in AV universal pacemakers. We recently encountered two cases in which VA conduction was responsible for atrial malpacing in patients with an implanted AV universal pacemaker, one programmed in DDD and one in DVl mode. Atrial malpacing was induced by the atrial refractoriness due to retrograde activation. In the first patient, it was observed when the pacemaker was programmed to a rale of 110 ppm (lower rate) and an AV interval of 200 ms in order to check crosstalk. In the second patient, it was observed after ventricular premature contractions.