bluuebunny/crossref_metadata_2025 huggingface dataset:
Autodiagnostic Pacemaker*
Authors: AUERBACH ALBERT A. , FURMAN SEYMOUR
Published: July 2006

Loss of normal pacemaker stimulation and for sensing functions requires prompt detection, automatic correction, and automatic and continuous “marking” of the intermittent failure, The autodiugnostic pacemaker (ADP) detects “failure to capture” (FC) by distinguishing, at its single stimulating and sensing electrode, between the normal biphasic cardiac response evoked by an adequate stimulus (corresponding to the QRS and T waves on the surface cardiogram) and the monophasic pseudo‐response generated by electrolonic spread of a subthreshold stimulating current. Detection of “failure to sense” (FS) spontaneous cardiac activity requires two amplifiers: a “timing control” amplifier of standard fidelity and standard (approximately 250 ms) refractory period, and a second amplifier which has negligible refractoriness and provides high fidelity amplification of all evoked and spontaneous activity. Failure to sense (FS) is defined as a specified number of consecutive failures to recycle correctly (he pacemaker's timing circuits. Similarly, a specified number of consecutive failures of the stimulus to evoke an active cardiac response is defined as a failure to capture (FC). When FC is detected, the ADP doubles the applied stimulus voltage and generates marker pulses which follow every subsequent stimulus by 40 ms. The marker pulses appear on the surface electrocardiogram, serving as an externally detectable “memory” of the earlier, possibly corrected, failure. When FS is detected, non‐stimulating marker pulses, of a difficult time relation (80 ms delay) to each stimulus, are generated continually and can also be detected externally. The ADP has been tested in 14 anesthetized, open‐chest dogs. Unipolar rather than bipolar electrodes were used as they provided more reliable stimulation and more satisfactory electrograms for detection.
Gas Pocket Causing Pacemaker Malfunction
Authors: LASALA ANTHONY F. , FIELDMAN ARNOLD , DIANA DANIEL J. , HUMPHREY CHESTER B.
Published: July 2006

Pacemaker niulfunction was attributed to the increase in impedance to current flow caused by a pocket of air separating the anodal contact pate of a unipolar generator from the overlying skin. Lack of capture was noted 20 hours after implantation. The malfunction was permanently corrected by bedside aspiration of the gas with a sterile syringe.
Unusual Demand Pacemaker Arrhythmia Due to Partial Recycling in the Relative Refractory Period
Authors: BAROLD S. SERCE , YOKOYAMA MASAYOSHI , WADA JURO , HIROSAVVA KOSHICHIRO
Published: July 2006

This report pretsents the electrocardiograms of a patient with a normally functioning lithium QRS‐inhibited pulse generalor that exhibited partial recycling with imappropri‐ately short escape intervols. The occurrence of partial recycling was time‐de‐pendent rather than voltage‐dependent, and was observed only when ORS com‐plexes fell within the relative refractory period of the pulse generator. This resutled in a complex arrhythmio simulating pulse generator maafunction. This ob‐servation re‐einphasizes the need for the physician to appreciute the technical char‐acteristics of pulse generotors to avoid Ihe unnecessary replacemsnl nf norniiilly funclioning units. (PACE VoJ. 2, March‐April, 1979.)
His Bundle Electrogram in Patients with Acute Myocardial Infarction
Authors: GOULD LAWRENCE , REDDY C.V.R. , KIM S.G. , OH K.C.
Published: July 2006

Thirty‐seven patients with acute myocardial infarction complicated by atripventricular or bundle branch block, or a combingtioh of both, had His bundle electrogram studies performed during their stay in the coronary care unit. The acute mortality of the 14 patients with a complicating bundle branch block was 50%. Pump failure was the main cause of death. Three patients in this group had a prolonged H‐V interval and one patient had a split bundle of His. The presence or absence of a prolonged H‐V interval did not affect mortality in this group of patients.

The acute mortality of the 16 patients with an inferior wall myocardial infarction was 6% The H‐V interval was normal in all but one of these patients. The atrioventricular block was caused by a proximal block in all cases.

The acute mortality of the seven patients with an anterior wall myocardial infarction was 29%. The H‐V interval was prolonged in two of seven patients. Pump failure was the acute cause of the deaths. The presence or absence of a prolonged H‐V interval did not affect mortality in this group of patients.
Adrenergically Mediated Ventricular Fibrillation in Probucol‐Treated Dogs: Roles of Alpha and Beta Adrenergic Receptors
Authors: ELHARRAR VICTOR , WATANABE AUGUST M. , MOLELLO JOSEPH , BESCH H.R. , ZIPES DOUGLAS P.
Published: July 2006

A high incidence of sudden death due to ventricular fibrillation (VF) has been observed in dogs under chronic treatment with probucol, a new hypocholesterolemic agent. The present study describes the cardiac electrophysiologic properties of probucol‐treated dogs and characterizes the electrophysiological response of these animais to manipula‐tion of the autonomic nervous system. There was no significant difference in the spontaneous sinus cycle length, the QT interval, refractory period of the atrium, ventricle or A‐V junction between normal and probucol‐treated dogs. Epinephrine produced VF with few and sometimes no preceding premature ventricular extra‐systoles. Electrical stimulation of the left stellate ganglion induced VF in 16/19 dogs whereas stimulation of the right stellate ganglion induced VF in 1/19 dogs. Phenyl‐ephrine induced VF in 0/19 dogs, isoproterenol in 5/19 dogs, but phenylephrine + isoproterenol induced VF in 9/11 dogs in which isoproterenol did not produce VF. α(phentolaminej or β (propranolol) blockade prevented initiation of VF by epi‐nephrine, phenylephrine + isoproterenol, and left stellate stimulation but a blockade did not prevent induction of VF by isoproterenoJ when isoproterenol alone produced VF. In this nonischemic model, we conclude that left stellate stimulation is a far more potent initiator of VF than right stellate stimulation and that induction of VF appears to require both α and β adrenergic receptor stimulation.
Clinical Classification of Generator and Electrode Failures
Authors: RICKARDS ANTHONY , NORMAN JOHN
Published: July 2006

A clinically based failure classification system is suggested for cardiac pacing generators and electrodes, and the method of reporting actuarial survival is reviewed. The difficulties of calculating potential generator lifetimes and the consequent definition of premature generator failures are discussed arid q pragmatic solution is offered.
Temporary Pacemaker Treatment in Open Heart Surgery: Pre‐ to Postoperative Changes in the Electrogram Characteristics
Authors: OHM OLE‐JÖRGEN , SKAGSETH ERLING
Published: July 2006

Thirty‐three patients undergoing cardiac surgery in general hypothermia were investigated during temporary pacemaker treatment for changes in right ventricular electrogram amplitudes (AMAX, UMAX) and maximum derivatives (DMAX, SMAX) from pre‐ to postoperative phase (AMAX = amplitude of the part of the electrogram with highest mean maximum derivative (SMAX), DMAX = maximum derivative, UMAX = maximum amplitude deflection). Standard commercially available electrodes were used in 28 of the patients. A paired comparison (n=29) showed a fall in AMAX from 8.64 ± 0.91 mV (mean ± SEM) preoperatively to 4.94 ± 0.43 mV (p < 0.001) between the 4th and 6th postoperative day; UMAX dropped from 11.09 ± 0.95 mV preoperatively to 5.44 ± 0.42 mV (p < 0.000001) from the fourth to the sixth postoperative day. In the same period DMAX fell from 1.57 ± 0.13 V/s to 0.67 ± 0.05 V/s (p < 0.000001), and SMAX from 0.76 ± 0.06 V/s to 0.32 ± 0.02 V/s (p < 0.000001). The most marked fall in amplitudes and maximum derivatives occurred during the first 24 hours. A slight, but nonsignificant increase occurred in amplitudes and maximum derivatives from the 4th to 6th postoperative day until the electrodes were removed the 10th to 19th postoperative day. Amplitudes and maximum derivatives were of the same value in patients with aortic valve compared with coronary heart diseases in spite of a more deteriorated mypcardial function in the former group. The changes in amplitudes and maximum derivatives followed the same pattern in the two groups from the pre‐to postoperative phase. This indicates that the additional local hyperthermia applied to the patients undergoing valve surgery was of no importance in the electrogram changes. Despite the fact that the electrogram maximum derivative and maximum amplitude needed to inhibit a temporary pulse generator are of a low magnitude, the values found were so small that they might provoke demand failure. This actually occurred in four patients.
Mechanical Wear of Pacemaker Lead Insulation. A Cause of Loss of Pacing
Authors: KRUSE IB MUNKSGÅRD , MARK JOACHIM , RYDÉN LARS
Published: July 2006

A pacemaker‐treated patient is described in whom Jead insulation defect caused sudden loss of capture. The defect was caused by mechanical wear by the posterior leaflet of the tricuspid valve and resulted in shunting of the pulse generator with a current drain exceeding the capacity of the pacemaker. In three further cases a similar explanation to sudden loss of pacing was highly suspected.
Physiological Cardiac Pacing
Authors: SUTTON RICHARD , PERRINS JOHN , CITRON PAUL
Published: July 2006

With the availability of reliable transvenous atrial leads and advances in electronic and battery technology, pacing for the restoration of the atrioventricular sequence has become practicable. This paper presents (1) a historical review of physiological cardiac pacing, and (2) a functional description of pacemakers currently available or in clinical validation. The indications and limitations of use for each is discussed on the basis of clinical experience in 176 patients. Predictions are made for future application of sophisticated pacemaker systems after the remaining clinical and technological barriers are overcome.
The Refurbished Puise Generator
Authors: MOND HARRY , TARTAGLIA SAM , COLE ANNETTE , SLOMAN GRAEME
Published: July 2006

With the advent of long‐life lithium puise generators, normally functioning puise generators with a potential life of more than five years have been removed from patients and become available for re‐implantation. Although puise generator refurbishing is widely employed, the practice has not been accepted in the United States. At The Royal Melbourne Hospital, all lithium puise generators removed because of patient death or other causes were washed in a quaternary ammonium compound and soaked in formaldehyde. Puise generators were then electronically tested and, if within specification, were made available for re‐implantation. Puise generators were then washed under sterile conditions in distilled water and gas‐sterilized with ethylene oxide. Between 1975 and 1978 (48 months), 600 puise generators were implanted and 93 puise generators removed. There were 56 deaths, 22 cases of pre‐erosion, erosion, or infec‐tion and 15 elective removals either due to lead problems or impending power source depletion. Eighty‐three (89%) puise generators were refurbished (14% of total implants). This included 12 puise generators refurbished on two occasions. Ten puise generators were returned to manufacturers, seven because of impending power source depletion, two with suspected electronic faults, and one with a damaged case. Two complications occurred in patients with refurbished puise generators. An infective process present with the previous puise generator spread to a new pocket. The other puise generator was removed 35 months post second implantation because of impending power source depletion. Primary infection or unusual tissue reactions did not occur. Puise generator refurbishing as described was found to be a safe and economic procedure.
Sources of Error in the Determination of Output Voltage of Pulse Generators by Pacemaker System Analyzers
Authors: BAROLD S. SERGE , ROEHRICH DENNIS R. , FALKOFF MICHAEL D. , ONG LING S. , HEINLE ROBERT A.
Published: July 2006

The use of threshold or pacemaker system analyzers with widely different characteristics has introduced potential sources of error in the determination of the output voltage of pulse generators. This is further compounded by the availability of pulse generators with diverse waveform configurations and programmability capabilities. Because of this non‐uniformity, the physician must have some rudimentary knowledge of waveform characteristics and appreciate the limitations of threshold or pacemaker system analyzers to avoid the unnecessary replacement of normally‐functioning pulse generators.
The Effects of Electrode Position on the Detection of the Transvenous Cardiac Electrogram
Authors: HUGHES HOWARD C. , BROWNLEE ROBERT R. , BERTOLET ROY D. , NEFF PAUL , SLUETZ JAMES E. , TYERS G. FRANK O.
Published: July 2006

Adequate sensing of the cardiac electrogram is a necessary requisite for all demand cardiac pacemakers. In order to define better the effects of position of the sensing electrode on the ability of the pacer to delect the electrogram, a specially designed lead system with a movable, large surface area (50 mm2) proximal ring electrode and a small surface area distal tip electrode was placed trans venously in 12 mongrel dogs. As the sensing electrode was moved away from the right ventricular apex, there were slight but insignificant decreases in R wave amplitude. When the electrode was moved retrograde through the tricuspid valve into the atria there was a marked decrease in R wave sensing; however, this was accompanied by a significant increase in P wave amplitude. Therefore, with a large surface area electrode, direct contact with the myocardium is not needed for the detection of adequate P and R waves. In addition, a pacer lead system utilizing this sliding sensing electrode design could be used to optimize sensing position, either for atrial or ventricular sensing pacemakers.
Evaluation of Cardiac Conduction in Anorexia Nervosa
Authors: GOULD LAWRENCE , REDDY C.V.R. , SINGH B.K. , ZEN B.
Published: July 2006

Anorexia nervosa is a disorder characterized by excessive dieting, a morbid fear of becoming obese, a distorted body image and amenorrhea in women, The condition is seen chiefly in girls and young women but also occurs in men. Death in anorexia nervosa may be sudden, and the mortality rate is the highest of any psychiatric disease.1 Despite investigations of its endocrine and psychiatric manifestations, little has been written about cardiac conduction in this entity. We report a patient with anorexia nervosa who presented with syncope due to a sinus bradycardia. His bundle electrograms were performed during the course of her hospilalization, and revealed that the abnormalities were reversible with food intake.
Characterization of Pacemaker Arrhythmias Due to Normally Functioning AV Demand (DVI) Pulse Generators
Authors: BAROLD S. SERGE , BAROLD S. SERGE , FALKOFF MICHAEL D. , ONG LING S. , HEINLE ROBERT A.
Published: July 2006

Normally functioning DVI pulse generators with different electronic characteristics may cause complex cardiac arrhythmias that must not be interpreted as pacemaker malfunction. When there is no refractory period after the atrial output, a DVI pulse generator may deliver atrial pacemaker impulses at irregularly shortened intervals and produce an increase in the atrial pacemaker rate compared with the programmed free‐running AV sequential rate. Theoretically this variation of the atrial cycle length can occur only within a well‐defined range that represents the difference between the ventricular and atrial output escape intervals. In reality, the interplay of the spontaneous sinus rate, duration of AV conduction, time of sensing the ventricular electrogram in relation to the surface QRS complex, and the programmed AV sequential time all influence the atrial pacemaker rate. DVI pulse generators may also create interesting arrhythmias such as pseudopseudofusion beats (delivery of an atrial spike within the QRS complex), double pseudofusion beats, and double pacemaker impulses within the QRS complex according to the electrophysiologic circumstances and specifications of the pulse generator.
The Malfunctioning Pacemaker System. Part I
Authors: MOND HARRY G. , SLOMAN J. GRAEME
Published: July 2006

The success of on implanted cardiac pacemaker is dependent upon the establishment of a harmonious relationship between the artificial pacemaker and the human receiver. Failure of a pacemaker system may arise from an electronic or mechanical defect within the pacemaker, a physiologic problem, or from a poor relationship between the normal function of both. Such malfunctions may necessitate the repair, replacement, or repositioning of a pacemaker component or removal of a source of external interference. True pacemaker malfunctions must be clearly distinguished from pseudo‐malfunctions, where there is no pacemaker system defect. These situations may, variously, require the repair of faulty testing equipment, reassessment of falsely interpreted test data, or treatment of the patient for an unrelated disorder. This paper outlines a system for investigating patients with suspected pacemaker malfunction. For simplicity, only malfunctions associated with the ventricular inhibited pacing system will be discussed.
Depression of Distal AV Conduction Following Ventricular Pacing
Authors: WALD ROBERT W. , WAXMAN MENASHE B.
Published: July 2006

A 61‐year‐old man presented with symptomatic 2° Mobitz II AV block in association with bifasciculor block. Ventricular pacing resulted in temporary depression of AV conduction. The extent of pacing‐induced AV block varied directly with the duration and rate of ventricular pacing. Intracardiac recordings proved that the site of spontaneous and pacing‐induced AV block was distal to the His bundle. Possible mechanisms by which this phenomenon may arise and several implications of practical importance are discussed.
Corrosion of Pacemaker Electrodes
Authors: PARSONNET VICTOR , VILLANUEVA ALEXANDER , DRILLER JACK , BERNSTEIN ALAN D.
Published: July 2006

As improvements in pacemaker components and design increase pacemaker life, problems with other components may emerge such as corrosion of the electrodes. Explanted electrodes were examined under a scanning electron microscope and the degree of corrosion was graded and correlated with the reasons for expiantation, the status of the explanted pacemaker, and the duration of the implant. Fifty‐six explanted electrodes were removed for loss of capture or sensing, pacemaker extrusion, broken wires, or after death. A numerical grading system was used to qualitate the degree of corrosion. The pacemaker itself was retrieved in 50 cases, permitting evaluation of the entire pacing system. The dc component of the pacemaker output was measured. Without She aid of magnification most electrodes appeared shiny and smooth. With one exception all corrosion was microscopic. Significant corrosion was seen on all pacemaker electrodes that had been connected to pacemakers with dc offset currents greater than 5 microamperes. All except the “youngest” explanted electrode showed some degree of corrosion. The data suggest that corrosion was directly related to the duration of implantation. With the possible exception of one case, no consistent adverse clinical effects were observed, even when electrodes were heavily corroded. Whether or not corrosion eventually will progress to the point that clinical problems become manifest cannot be predicted at this time.
Interpretation of Electrocardiograms Produced by a New Unipolar Multiprogrammable “Committed” AV Sequential Demand (DVI) Pulse Generator
Authors: Harold S. Serge , BAROLD S. SERGE , FALKOFF MICHAEL D. , ONG LING S. , HEINLE ROBERT A.
Published: July 2006

This paper describes our approach to the interpretation of electrocardiograms produced by a new unipolar multiprogrammable “committed” DVI pulse generator (Intermedics) during normal function. The arrhythmias engendered by this new DVI pacemaker may be better understood by conceptualizing the recycling mechanism in terms of a simple atrial pulse generator with two important qualifica‐tions: (1) the ventricular stimulus obligatorily follows the atrial stimulus after 155 ms (AV sequential interval); (2) the pulse generator senses ventricular events (via the ventricular electrode) but recycles according to its atrial timing cycle (AA interval). These characteristics lead in turn to two important consequences: at the QA interval (from the onset of a sensed QRS complex to the succeeding atrial stimulus) must be longer than the VA interval (from a ventricular stimulus to the succeeding atrial stimulus) by a period equal to or slightly greater than the AV sequential time. This may be considered to represent a form of bysteresis, by the pacemaker refractory period always starts at the onset of an atrial cycle (AA interval) and therefore occurs after the delivery of an atrial stimulus or after a sensed ventricular event. The above characteristics may cause pacemaker stimuli to fall within the P wave, PR interval, QRS, ST segment and the ascending limb of the T wave during normal function of the pulse generator. Superficially, these peculiarities resemble malfunction and may be quite befuddling but they all occur predictably according to the electronic design of the pulse generator. (PACE, Vol. 4, November‐December, 1981)
Successful Removal of a Severed Transvenous Pacemaker Electrode
Authors: GOULD LAWRENCE , MAGHAZEH PAUL , GIOVANNIELLO JOSEPH
Published: July 2006

The ease and simplicity of the transvenous approach to permanent pacing continue to be among its greatest advantages. However in a small proportion of transvenously paced patients complications can occur, A rare complication is an incompletely removed pacing catheter with subsequent embolization to more central parts of the cardiovascular system.’This communication reports the migration of a severed transvenous pacemaker electrode and its removal from the left iliac vein with a femoral‐ventricular pigtail catheter, (PACE, Vol. 4, November‐December, 1981)
Inadvertent Atrial Location of a Sutureless Epicardial Pacemaker Electrode
Authors: LOK WAI BONG , THOMAS ARTHUR N. , GOLDSCHLAGER NORA
Published: July 2006

A 70‐year‐old woman had an epicardial pacing system implanted after transvenous right ventricular endocardial pacing resulted in cardiac perforation. At the time of revision of the epicardial system for pacing failure, it was noted that one of the bipolar epicardial electrodes was pacing atrial tissue. The differential diagnosis of this unusual finding is discussed and recommendation urged for systematic analysis of pacing system function at the time of implant, in order to avoid inadvertent electrode plpcement.
Myopotential Inhibition of Unipolar AV Sequential (DVI) Pacemaker
Authors: ECHEVERRIA HIPOLITO J. , LUCERI RICHARD M. , THURER RICHARD J. , CASTELLANOS AGUSTIN
Published: July 2006

Whereas myopo‐tential inhibition of QRS‐inhibited (VVI) pacemakers is well known, its occurrence in patients with AV sequential (DVI) pacemakers has not been reported The present communication deals with spontaneous and induced myopofential inhibition of a muitiprogrammabie Intermedics unipolar AV sequential (DVI) pacemaker The bedside maneuvers that were performed in the patient exposed the problem, therefore serving to estabish the diagnosis Although external adjustment of the sensitivity was the simple, non‐invasive solution in this case, more studies are required to determine the success rate of this approach as well as the incidence and clinical significance of myopotential inhibition of unipoiar DVI pacemakers
Bradycardia Dependent Ventricular Tachycardia Facilitated by Myopotential Inhibition of a VVI Pacemaker
Authors: IESAKA YOSHITO , PINAKATT TERESA , GOSSELIN ARTHUR J. , LISTER JOHN W.
Published: July 2006

Bradycardia‐dependent ventricular tachycardia was facilitated by long asystolic pauses caused by myopotential inhibition of a VVI pacemaker. Increasing the pacemaker rate by reprogramming temporariiy eliminated the problem. This case demonstrates that myopotential inhibition can result in serious clinical ventricular tachyarrhythmias
Atrial Fibrillation During A‐V Sequential Pacing
Authors: FURMAN SEYMOUR , COOPER JEROME A.
Published: July 2006

Atrial fibrillation resulted from competition between the P wave and a unipolar cathodal stimulus from the atrial output of an A‐V sequential pacemaker Review of 31 patients with recently implanted A‐V sequential pacemakers revealed that five, who had not had atrial fibrillation or flutter before implant, developed atrial arrhythmia early after implant As occasional placement of an atrial stimuJus in tlie atrial vulnerable period can occur during normal function, pacer induced atrial fibrillation must be expected Atrial sensing to ensure lack of competition between pacer and spontaneous atrial activity is desirable
Malfunction of a Sheath‐Retracting Active‐Fixation Pacemaker Electrode Due to Impacted Endocardium
Authors: SALEM DEEB N. , ISNER JEFFREY M.
Published: July 2006

A patient is described in whom a sheath‐retracting active‐fixation pacemaker electrode dislodged shortly after successful transvenous implantation in the right atrial appendage. Attempts to reposition the lead were unsuccessful. Examination of the explanted electrode disclosed that inability to reposition the electrode was due to the fact that impacted tissue around the electrode “screw” prevented its being re‐advanced out of its polyurethane housing. (PACE, Vol. 5, March‐April, 1982)
Usefulness of Echocardiography in Cardiac Pacing
Authors: NANDA NAVIN C. , BAROLD S. SERGE
Published: July 2006

The role of echocardiography in cardiac pacing is reviewed. We discuss its usefulness and limitations in the identification of pacing catheters, diagnosis of myocardial wall perforation, evaluation of catheter displacement/malposition, manipulation and positioning of catheters without recourse to fluoroscopy, identification of pacemaker induced thrombosis, diagnosis of venous anomalies and assessment of left atrial function in atrioventricular sequential (DVI) pacing. (PACE, Vol. 5, March‐April, 1962)
A Possible Role of the Specialized Conduction System in the Conversion of Ventricular Tachycardia to Ventricular Fibrillation*
Authors: SCHROEDER PAUL , LYONS CHALMERS
Published: July 2006

Electrode recordings from the right bundle brunch. His bundle. and right atrium in a canine preparation enabled us to observe the activation of the ventricular myocardium and the specialized conduction system during the conversion of ventricular tachycardia to ventricular fibrillation. At times when ventricular tachycardia degenerated to ventricular fibrillation, asynchronous activation of the right bundle branch and the ventricular myocardium was frequently noted. Such asynchrony of activation was not seen during the spontaneous conversion of ventricular tachycardia to sinus rhythm. We suggest that this asynchronous activity produces increasing fractionation of ventricular activation fronts, which in turn yields fihrillation. (PACE, Vol. 5, September‐October, 1982)
A New Symbolic Language for Diagramming Pacemaker/Heart Interaction
Authors: BROWNLEE R.R. , SHIMMEL‐GOLDEN J.B. , DEL MARCO C.J. , FURMAN S.
Published: July 2006

A new symbolic language is presented that can be used to diagram pacemaker/heart inleractions. The language symbolically indicates “normally” conducted and ecfopic events; pacemaker stimuli; pacemuker capture of the chamber; triggered pacemaker stimuli by “normal” or eclopic events: as well as such anomalous pacemcker/heart interactions as failure to sense; “crosstalk” between electrodes; and “normal,” eclopic. of paced events in one chamber sensed by the electrode in the other chamber. In addition, symbols are provided to represent antegrade and retrograde accessory pathway conduction, and electronic and physiological refractory intervals, A common baseline is used to separate symbols for atrial activity. above the baseline, from those for ventricular activity, below the baseline. Parallel baselines are used to plot refractory intervals. Thus, even complex dual‐chamber pacemaker operating modes can be represented with intrinsic and stimulated cardiac response to pacemaker operation. The language can be sketched out informally for description of general concepts or drafted on millimeter grid paper to make precise timing notations. It is especially useful for interdisciplinary communication of ideas about complex pacemaker/heart interactions. (PACE, Vol. 5. September‐October, 1982)
Atrioventricular Sequential Pacing: Comparison with Ventricular Pacing Using Systolic Time Intervals
Authors: WHITING RICHARD B. , MADIGAN NIALL P. , HEINEMANN FRED M. , CURTIS JACK J. , REID JOHN
Published: July 2006

Nine patients with programmable atrioventricular sequential pacers were studied using systolic time intervals (QS2—the total electrical and mechanical systole, left ventricular ejection time, and pre‐ejeclion period). These measurements were obtained by simultaneous recording of the electrocardiogram, phonocardiogram. and carotid pulse tracing. There was a dramatic fall of left ventricular ejection time (LVET) and an increase of the pre‐ejection time (PEP) in all patients when the pacers were programmed from the atrioventricular to the ventricular mode at constant heart rate. This resulted in an increase of the ratio PEP/LVET from 428 to 574 suggesting loss of ventricular function. These measurements all reversed to baseline values when the pacers were reprogrammed back to the atrioventricular mode. This study suggests systolic time intervals might be useful to select non‐invasively pacer parameters such as mode, rate, and effective PR interval in order to provide the best hemodynamics in a given patient.
Pacemaker Therapy in the Seventies: Interaction of Patient Age, Time of Implant, and Indications for Pacing
Authors: HERMAN NEIL D. , MITCHELL JANET M. , DICKSON SHARON E.
Published: July 2006

In the 1970s, 707 patients received a primary pacemaker implant in our hospital. An analysis of the indications for pacemaker therapy revealed that one‐third had third degree heart block, one‐third had sick sinus syndrome and one‐third had other indications. The distribution of indications was identical in all age groups. Furthermore, this distribution did not change from the first half of the decade to the second.
The Use of QT Interval to Determine Pacing Rate: Early Clinical Experience
Authors: RICKARDS A.F. , DONALDSON R.M. , THALEN H.J.Th.
Published: July 2006

Malgré la disponibilité de stimulateurs du lype physlologique, il restent des inconvenients inhérenls à leur fonctionnement. En théorie, les sfimulaleurs synchrones de ľoreillette (VDD ou DDD) sont ideal, mais en pratique leur performances sont limitées pur un fourchelte assez etroite des frequences cardioques chez un certain nombre de majades. Nous décrivons donc le système TX qui incorpore à la fois la stimulation ventriculaire, et le recueil de ľonde T déterminé par ľespace QT. Ge stimulateur TX distingue entre tachycardies physiologiques et pathologiques, et fournit un rythme asservi même en ľabsence ?activité auriculaire.

Despite the current availability of physiologic pacing systems, there remain distinct disadvantages associaled with their operation. Although in theory the atrial synchronous pacemaker (VDD or DDD) is the ideal system, in practice it performs satisfoctorily over a very limited range of heart rates in a limited number of individuals. We describe the TX system which incorporates ventricular pacing and is driven by T wave sensing determined by the QT interval. This pacemaker can distinguish between physiologic and pothologic tachycardias while providing an almost unlimited rate response even in the presence of on unresponsive atrium.
Pseudomalfunctions of Dual‐Chamber Pacemakers
Authors: PARSONNET VICTOR , BERNSTEIN ALAN D.
Published: July 2006

La prolifération de la stimulation auriculoventriculaire a crée de nombreux cas de “pseudo‐dysfonctionnemenl” du stimulateur. En ce qui concerne ľinterpretation electrocardiographique, il est devenu parfois impossible de faire la distinction entre normal et anormal. La classification et les critères de ces phénomenes sont décrits. Il semble que seule la connaissance parfaite du fonctionnement de cheque stimulateur préviendra la fausse interprétation des tracés éléctrocardiographiques.

The proliferation of dual‐chamber pacemakers has created a host of electrocardiography problems relating to interpretation. The term “pseudomalfunction” identifies an electrocardiographic finding that looks like pacemaker malfunction but is not. Several different models of dual‐chamber pacemakers, which are either presently available or in clinical evaluation, produce different types of pseudomalfunc‐tions. These are classified and described. Intimate knowledge of individual pacemaker characteristics is required for proper evaluation of these units.
Atrial Synchronous Ventricular Inhibited Pacing (VDD): An Underutilized Mode of Pacing
Authors: MESSENGER JOHN C. , GREENBERG PAUL S. , WARREN JAY , CASTELLANET MARK J.
Published: July 2006

Après ľintroduction de la stimulation en VAT, le mode stimulation en VDD représente un progrés. Ses bénéfices physiologiques sont maintenant bien prouvés alors que cette stimulation n'est utilisée que dans 1 % des cas. Les progrés de la program‐mation de la période refractaire auriculaire permettant de maitriser les tachycardies induites laissent espérer une augmentation du pourcentage ?utilisation du mode de stimulation en VDD chez les malades porteurs ?un bloc de haul degré induit par ľeffort et avec fonction sinusale stable.

The design of atrial synchronous, ventricular inhibited (VDD) pacemakers has been improved. Physiologic long‐term benefit has now been established, although this mode of pacing accounts for approximately one percent of implanted devices. With the ultimate control of pacemaker‐mediated lachycardia through atrial refractory programming close at hand or already available, one might expecl an increase in VDD pacing in patients with exercise‐induced high degree heart block and stable sinus node function.
Initial Results with an Activated Pyrolytic Carbon Tip Electrode
Authors: GARBEROGLIO BRUNO , INGUAGGIATO BRUNO , CHINAGLIA BENITO , CERISE OSVALDO
Published: July 2006

Le bilan de ľétude initiale ?une nouvelle électrode en carbone est présenté. Les résultats des tests in vitro montrent une économic ?énergie meilleure qu'avec celle obtenue avec des électrodes en platine. Des études histologiques chez ľanimal montrent également une plus faibler éaction tissulaire àľinterface électrode‐coeur. Enfin, chez 121 malades porteurs de ces sondes, les courbes puissance‐duree ont des valeurs basses de rheobase. Les seuils de stimulation chronique sont constament bas. Ces resullats initiaux soulignenl la bonne performance de celte électrode au carbone.

The initial results acquired from testing of a new activated pyrocarbon electrode for cardiac pacing are presented. In vitro testing has shown energy efficiency to be higher than for platinum electrodes. Histologic examination of implanted leads in animals has demonstrated a less significant tissue reaction at the tip. Finally, in a clinical trial of 121 patients with these leads, strength‐duration curves have low rheobase values. Chronic thresholds are often consistently low. These reports suggest very satisfactory results with this pyrolytic carbon electrode.
New Low Energy Transvenous Cardioverting and Pacing Electrode
Authors: BOURGEOIS I. , SMITS K. , KALLOK M.
Published: July 2006

Une sonde endocavilaire (Medtronic Model 6880) a été developpée pour la stimulation ventriculaire, la cardioversion et pour la défibrillation endocavitaire, en utilisant un courant de basse énergie. Les résultats chez le chien aussi bien que les premières experiences chez ľhomme indiquent que cette sonde sera utile dans le traitement des tachyarythmies malignes.

A new endocurdial catheter electrode (Medtronic model 6880) is described which can be used for ventricular pacing and for intrucavitary cardioversion and defibrillation. Initial results in dogs and preliminary clinical trials in humans indicate that this catheter will extend the usefulness of electrical stimulation therapy for treatment of life‐threatening tachyarrhythmias.
Central Body Temperature as a Guide to Optimal Heart Rate
Authors: GRIFFIN JERRY C. , JUTZY KENNETH R. , CLAUDE JOHN P. , KNUTTI JAMES W.
Published: July 2006

Les stimulateurs cardiaques à fréquence fixe ne restaurent pas la fonction hémodynamique normale. Puisque un pourceniage élevé de patients porteurs ?un stimuJateur cardiaque a des anomaJies auriculaires, un outre moyen de “piloter” le pacemaker est présentér celui de la témperature du sang dans ľoreillette droite. Les sondes à enregistrement thermique mesurent la variation de température pendant ľexercice et peuvent servir de guide pour déterminer la fréquence cardiaque optimale.

Studies in man suggest that fixed‐rote artificial pacemakers do not return hemodynamic function to normal, since the principal mechanism for the increase in cardiac output with exercise, increased heart rate, is not restored. Special pacemakers are available that can detect atrial activity and pace the ventricles in coordination, but nearly half of the patients receiving artificial pacemakers have abnormal atrial function fatrial fibrillation, sick sinus syndrome). This study examined the effects of exercise on the temperature of blood returning to the right atrium. Precision thermistors, placed in the right hearts of conscious dogs, recorded temperature increases of 1°C (range 0.4–1.5°C) during submaximal treadmill exercise. Temperature change correlated well with work load and changes in heart rate.
Respiratory Rate as a Determinant of Optimal Pacing Rate
Authors: ROSSI PAOLO , PLICCHI GIANNI , CANDUCCI GIANCARLO , ROGNONI GIORGIO , AINA FRANCO
Published: July 2006

Des essais ont été faits dans ľutilisation des paramètres bialogiques pour déterminer la fréquence optimale de stimulation cardiaque. Dans cette étude, le rapport entre fréquence respiratoire et fréquence cordiaque a étéétabli chez 67 patients au cours de ľexercice. Ensuite, un système de stimulation cardiaque qui repondrait àľactivation radiotélémétrique a été posé chez onze patients. Dans deux cos un système automatique a été implanté avec succès. A present, les résultats de cette stimulation pilotée par la fréquence respiratoire sont satisfaisants.

Efforts have been made to utilize biologic parameters for determining optimal cardiac pacing rates. In this study of 67 patients, a significant relationship between heart rate and respiratory rate was observed during dynamic exercise. A system using a radiofrequency activator to modify pacing rate is described. Eleven patients have received VVI pacemakers with a similar implanted radioreceiver coil. In two patients the fully automatic system has been successfully implanted. The experience with respiratory rate as a determinant of pacing rate is encouraging.
Effect of the Antiarrhythmic Agent Flecainide Acetate on Acute and Chronic Pacing Thresholds
Authors: HELLESTRAND K.J. , BURNETT P.J. , MILNE J.R. , BEXTON R.S. , NATHAN A.W. , CAMM A.J.
Published: July 2006

To determine the effect of flecainide acetate, a Class IG antiarrnythmic drug, the medication was given to 28 patients with ventricular pacing electrodes. Eleven patients with temporary pacing electrodes (Group I) received intravenous flecainide (2 mg/kg over 10 minutes). Ten patients with chronic permanent electrodes (Group II) were given the same dose at the time of elective pulse generator change. Seven, with implanted multiprogrammable pacemakers capable of threshold analysis (Group III), were given intravenous flecainide and 5 of these were then given the drug orally for up to 3 weeks (100 mg/day increasing to 400 mg/day). In Group I the threshold measured at a pulse width of 0.5 ms rose from a control value of 0.66 to 1.44 volts after 10 minutes (p < 0.01). In Group II the threshold rose from 1.73 to 2.13 volts (p < 0.01) and 2 patients had total suppression of their ventricular escape rhythm for approximately one hour. In Group III patients, intravenous flecainide resulted in a rise of the pulse width threshold measured at 2.7 volts from 0.14 to 0.22 ms (p<0.02) and at 4.9 volts from 0.06 to 0.11 ms (p<0.05) after 10 minutes. After 3 weeks of oral therapy the threshold at 2.7 volts had risen from 0.09 to 0.28 ms (p < 0.02) and al 4.9 volts from 0.06 to 0.16 ms (p< 0.05). Flecainide significantly increased both acute and chronic thresholds and the most marked rise (> 200%) occurred during chronic oral therapy. Both intravenous and oral flecainide should be used with care in patients with either temporary or permanent pacing systems.
A New Transvenous Lead for Both Atrial and Ventricular Pacing
Authors: KRUSE I. , PETERS P. , RYDÉN L.
Published: July 2006

A new transvenous fined unipolar lead (Medtronic SP 342) has been implanled in 56 patients; 35 leads were positioned in the atrium and 34 in the ventricle. The lead comprises a trifilar DBS‐conductor within an insulation of poiyurelhane. four symetrically placed polyurethane tines furnished with scallops and a platinum‐indium ring‐tipped electrode. The scallops in the tines ensure flexibility and a small effective diamclerof the lead which makes the choice of vein less critical than with most previous lined leads. It allows use of the same normally sized vein for a second lead for dual‐chamber sensing pacing. Mean atrial and ventricular electrogram amplitudes (SD) were 4.6 ± 1.2 mV and 8.8 ± 4.4 mV; mean atrial and ventricular stimulation thresholds were 0.8 ± 0.3 V and 0.4 ± 0.2 V; and mean a trial and venlricular lead impedances were 415 ± 114 ohms and 456 ± 105 ohms, respectively. The results of this study show that the SP 342 lead is useful especially in dual chamber systems.
Two‐Dimensional and Doppler Echocardiographic Identification of Infrahepatic Interruption of Inferior Vena Cava with Azygos Continuation
Authors: SUTHAR ARVIND L. , NANDA NAVIN C. , HARRIS PETER J.
Published: July 2006

Congenital anomalies of systemic venous return have been associated with pacemaker complications. Awareness of the existence of these anomalies prior to catheterization can lead to the utilization of an alternate route for pacing, avoiding undue delay in the institution of pacing which may be urgently needed. Pulse Doppler echocardiographic demonstration of turbulent flow in the azygos vein and superior vena cava combined with subcostal two‐dimensional echocardiographic finding of a small channel opening into the right atrium appear to be highly specific findings in the diagnosis of infrahepatic interruption of inferior vena cava with azygos continuation.
Influence of the Autonomic Nervous System on the Genesis of Cardiac Arrhythmias
Authors: ZIPES DOUGLAS P. , BARBER MICHAEL J. , TAKAHASHI NOBUHIRO , GILMOUR ROBERT F.
Published: July 2006

The purpose of this report is to present a brief overview of the concepts concerned with the potential effects of the autonomic nervous system on the genesis of cardiac arrhythmias. First, we present data indicating the functional importance of presynaptic and postsynaptic vagaJ modulation of adrenergic neurotransmission on electrical activity in sinus and A‐V nodes, and contractile activity of canine cardiac Purkinje fibers. Second, we indicate the possible intraventricular adrenergic and vagal pathways to the ventricles, suggesting that sympathetic fibers travel in the epicardium while vagal fibers appear to cross the A‐V groove in the epicardium but then take an intramural route for part of their course. Finally, we demonstrate that a lesion such as a myocardial infarction can interrupt neural fibers traveling through the infarction to affect nominfarcted myocardium distal to the infarction. These factors may play a role in the genesis of some cardiac arrhythmias.
Ocular Pneumoplethysmography in Cardiac Pacing
Authors: GEE WILLIAM
Published: July 2006

Varialions in ocular blood flow (OBF) reflect variations in cardiac stroke output very closely. The use of ocular pneumopthysmography (OPG‐Gee) for the measurement of OBF is a simple. noninvasive method of assessing the hemodynamics of ventricular versus atrioventricular sequentia pacing.
R‐wave Triggering of External Instrumentation during Cardiac Pacing
Authors: BERNSTEIN ALAN D. , PARSONNET VICTOR
Published: July 2006

Monitoring and diagnostic instruments often utilize electrocardiographic R‐wave detection for measuring hearl rate or for timing of measurement processes. During cardiac pacing stimulus artifacts commonly interfere with the operation of such instruments because they are misinterpreted as R‐waves. This phenomenon creates problems in assessing the hernodynamics during gated blood‐pool scans, coronary care monitoring, and intra‐aorlic balloon pumping. A straightforward solution is found in the nature of the electrical signals involved in which the stimulus artifacts are detected independently and are removed from the signal fed to the R‐wave detector.
Long‐term Prevention of Vagal Atrial Arrhythmias by Atrial Pacing at 90/Minute: Experience with 6 Cases
Authors: COUMEL PHILIPPE , FRIOCOURT PATRICK , MUGICA JACQUES , ATTUEL PATRICK , LECLERCQ JEAN‐FRANCOIS
Published: July 2006

Six patients (5 men, 1 woman) with a history ranging from 3–16 years of resistant vagal atrial arrhythmias were treated by atrial pacing at a rate of 90Jmin. These patients have been followed up for an average of 5.5 years (range 2–11 years) with favorable resutls. The arrhythmias were charactemed by daily or weekly attacks of rypical alrial flutter and atrial fibrillalion occurring mainly or exclusively at night, at rest, or in the digestive periods in otherwise normal hearts of middle‐aged palients (first attack between 25 and 54, mean 40). The arrhythmias werc resistant to quinidinc, and were usually aggravated by digitalis, beta‐blockers and verapamil. Amiodaroneisusually the only effective drug in this syndrome, but was not used before pacing in the 2 first cases, and was in effective in the other 4 cases. Electrophysiologic studies confirmed the absence of sick sinus syndrome, and the close relationship betwecn a relative bradycardia and the onset of the arrhythmia. Atrial pacing alone totally controiled the arrhythmia in 1 palient; amiodarone was used in conjunction with pacing in 3 palients. In 1 patient the improvement was clear but incomplete, and in 1 patient permanent alrial fibrillation occurred shortly afler pacemaker implantalion.