bluuebunny/crossref_metadata_2025 huggingface dataset:
Permanent Pacemaker Implantation Using the Femoral Vein: A Preliminary Report
Authors: ELLESTAD MYRVIN H. , CASO RICHARD , GREENBERG PAUL S.
Published: July 2006

A permanent pacemaker was implanted through the femoral vein in 23 patients using the percutaneous puncture technique. The pulse generator was placed in the lower abdominal wall. The method is simple and reduces (he time necessary to accomplish implantation. Catheter extrusion in one patient was easily corrected. Another patient had late thrombophlebitis, possibly unrelated to the procedure. Catheter dislodgement occurred in four (4) patients and penetration of the right atrial appendage and right ventricular apex each occurred once. We believe these problems can be circumvented with more experience and expect the femoral approach to be a simple and practical method of permanent pacemaker implantation.
The Value of Redundancy in Chronic Bipolar Pacemaker Electrode Systems
Authors: HOLMES DAVID R. , GERSH BERNARD J. , SHUB CLARENCE , MALONEY JAMES D. , MERIDETH JOHN
Published: July 2006

Bipolar pacing systems, because of the presence of two intracardiac electrodes. provide lead redundancy. This allows conversion of bipolar to unipolar pacing or the reversal of lead polarity. During a 3‐year period, this redundancy was utilized in 34 (13.7%) of 248 patients with chronic bipolar lead systems during follow‐up pacemaker surgery. Of the 34 patients, elective pulse generator change was the most frequent indication for surgery (23 patients) and in this group redundancy was used most often to select the lead configuration with the highest R‐wave amplitude and lowes stimulation threshold, or to solve the problem of weld defects of the connector pins or frayed insulation. The remaining 11 patients underwent surgery for pacemaker system malfunction and in this group redundancy was used to avoid the need for lead repositioning or placement of a new catheter system. Lead redundancy in those patients in whom bipolar pacing has been selected provides flexibility at the time of additional pacemaker surgery, and its use may abviate the need for a change in catheter system when stimulation thresholds are excessive, wire fraction is irreparable, or bipolar sensing signals are inadequate.
Use of the Esophageal Lead in the Diagnosis of Mechanisms of Reciprocating Supraventricular Tachycardia
Authors: GALLAGHER JOHN J. , SMITH WARREN M. , KASELL JACK , SMITH WILLIAM M. , GRANT AUGUSTUS O. , BENSON D. WOODROW
Published: July 2006

Recent studies have emphasized the role of concealed accessory pathways in reciprocating supraventricular tachycardia. Diagnosis has generally required multicatheter electrophysiologic study. We recorded esophageal electrograms during study in 16 patients with reciprocating tachycardia due to reentry using an accessory alriovenlricular pathway, and in 12 patients with reciprocating tachycardia due to reentry in the AV node. The interval from onset of ventricular depolarization to earliest atrial activation (V‐AMIN), ear‐liest atrial activity on the esophageal lead (V‐AESO).and high right atrium (V‐HRA) was measured. No patient with RT due to an accessory atrioventricular pathway had a V‐AMIN or V‐AESO less than 70 ms, or a V‐HRA less than 95 ms. In contrast, 11 of 12 patients with reentry in the AV node had V‐Aggo intervals less than 70 ms. Esophageol recording during reciprocating tachycardia provides a simple screening procedure available to all practicing physicians to exclude the diagnosis of accessory atrioventricular pathways in the genesis of paroxysmal supraventricular tachycardia.
Three Hundred and Fifty‐Three Consecutive Patients with Permanent Transvenous Pacemakers
Authors: GOULD LAWRENCE , REDDY C.V.R. , MAGHAZEH P. , CIFARELLI F. , BREVETTL G. , SHIN C.S. , SAADAT S.
Published: July 2006

The safety and convenience of the tronsvenous approach to long‐term endocardial pacing are well established, but its principal drawback is electrode displacement. The reported incidence of this complication varies between 3.0% fo 36.7%, and is highest in the early post‐implantation period before endocardiaL fixation of the electrode tip. Recently Brewster and Evans determined that the electrode displacement rate in 21 published series averaged 14.3% However, the Inter Society Committee on Heart Diseases (ICHD) report on pacemakers states that a rate of early displacement greater than 5% calls for a critical review of results. The training and expertise of the persons inserting the pacemaker electrodes undoubtedly are major factors which determine the proper transvenous placement of permanent cardiac electrodes. This paper deals with our clinical experience of 353 patients who received permanent transvenous peacemakers during the period September 1, 1974 through March 1. 1979 with emphasis on problems and complications encountered and overall results.
Automated On‐Line Measurement of Electrophysiologic Intervals During Cardiac Catheterization
Authors: GILLETTE PAUL C. , GARSON ARTHUR , ZINNER ALEX , KUGLER JOHN D. , KUEHNEMAN GARY , McNAMARA DAN G.
Published: July 2006

A small dedicated, computer‐controlled waveform analyzer was used to automatically measure the R‐R cycle length, low right atrium to His, and His to ventricle intervals obtained during electrophysiologic studies on 35 patients. These measurements were compared to intervals handmeasured separately and found to correlate well (0.92, 0.63, and 0.75, respectively). The sources of error, possible pitfalls, and future uses of this technique are discussed.
Pacemaker and Patient Response to the “Point of Sale” Terminal as an Actual and Simulated Electromagnetic Interference Source
Authors: PANNIZZO FRANK , FURMAN SEYMOUR
Published: July 2006

In response to two instances of pacemaker patient complaints of symptomatic episodes in the presence of a “point‐of‐sale” terminal, comprehensive tests were performed for possible electromagnetic interference effects. Power line frequency and radar transmitter tests in the laboratory indicated that no significant problems exist for recently manufactured pacemakers in the everyday environment. Laboratory and clinical tests with 271 patients and 54 pacer models demonstrated no hazard from “point‐of‐sale” terminals. Patients showed a generally benign attitude toward potential interference and very low occurrence of random intermittent pacer malfunction or effects from myopotentials.
Myopotential Inhibition of Unipolar QRS‐inhibited (VVI) Pacemakers, Assessed by Ambulatory Holter Monitoring of the Electrocardiogram
Authors: BREIVIK KJELL , OHM OLE‐JØGEN
Published: July 2006

Seventy‐four patients with unipolar QRS‐inhibited pacemakers (VVI) were Holter monitored to assess the occurrence of pacemaker inhibition caused by skeletal muscle potentials during daily activities. Fifty patients had high‐grade atrioventricular block and 24 had sinoatrial disease. Chest wall stimulation prior to monitoring revealed asystole of > 4 seconds duration in 22 patients, and ventricular rates between 25 and 56 beats per minute in 52 patients. Fifty‐one patients (69%) had one or more episodes of pacemaker inhibilion from myopotentials. Inhibition occurred in all types of pacemakers studied, but was most frequent and of longest duration in patients with Siemens‐Elema 207/70 (13/14 patients), Cordis OmniStanicor (6/7 patients), CPI Microlith (5/6 patients), and Medtronic 5945 (8/30 patients). This was not unexpected considering the filter characteristics of the pacemakers. Nine patients (12%) presented symptoms which might be ascribed to pacemaker inhibition. The longest asystole observed was 3.2 s. Seven patients had pacemaker spikes falling on or near T‐waves of spontaneous heart beats because their pacemakers had been rendered refractory by myopotentials. No serious arrhythmias were seen during episodes of pacemaker inhibition or interference. More emphasis should be put on the improvement of filter characteristics of unipolar VVI‐pacemakers. Pacemaker patients with symptoms of myopotential inhibition should be equipped with either a bipolar or ventricular triggered (VVT) pacemaker or with a sensitivity and/or pacing mode programmable pacemaker.
Clinical Evaluation of an Improved High Resolution ECG Cart for Recording the His Bundle Electrogram Non‐Invasively
Authors: MACGREGOR DAVID C. , ROZANSKI J.J. , CASTELLANOS A.
Published: July 2006

The Marquette high resolution MAC‐3 ECG cort con record the His bundle electrogram non‐invasively at the bedside. The second generation MAC‐1 has several unique features and technical advances which may now make the technique clinically applicable. In addition to amplification and signal averaging, an adjustable input filtration system excludes beats which are unacceptably “noisy” compared to a 4 beat template. Thus, extremely “clean” signals are presented for processing by the averages allowing resolution of very low amplitude signals. Clear unequivocal His bundle recordings were obtainable in 25 of 55 patients (45%). A correlation coefficient of +.97 was obtained between invasive and non‐invasive HV intervals. The 55% failure rate was attributed to prolonged atriol activity in 31%, short PR in 9%, and technically unsatisfactory recordings with excessive or overwhelming noise which did not allow appreciable signal resolution in 15%.
Ventricular Tachycardia Initiated by Both Normally and Aberrantly Conducted Atrial Premature Beats
Authors: BERMAN NEIL D.
Published: July 2006

Eiectrophysiologic studies were performed in a 72‐year‐old female with recurrent ventricular tachycardia in whom all documented spontaneous episodes were initiated by atrial premature beats. These studies confirmed the diagnosis of ventricular tachycardia and its initiation by atrial premature beats. Both normally and aberrantly conducted atrial premature beats were capable of initiating the tachycardia. With aberrant prematures the onset of the tachycardia was delayed in proportion to the delay in the right bundle branch. Triggered automaticity and re‐entry were equally plausible as underlying mechanisms for this arrhythmia.
The Sock Electrode Array: A Tool for Determining Global Epicardial Activation during Unstable Arrhythmias
Authors: HARRISON LURA , IDEKER RAYMOND E. , SMITH WILLIAM M. , KLEIN GEORGE J. , KASELL JACKIE , WALLACE ANDREW G. , GALLAGHER JOHN J.
Published: July 2006

The conventional technique for mapping the sequence of epicardial activation uses a hand‐held electrode moved over the heart to record from a number of epicardial sites one at a time, and requires 5–15 minutes to record from 50 or more sites distributed over the entire ventricular epicardium. This method is inadequate for arrhythmias that are transient or vary from beat to beat. To overcome these limitations the “sock electrode array,” a contour‐fitting sock containing 26 or 52 electrodes, has been developed. The nylon mesh sock is pulled over the heart and permits simultaneous recording of potentials from electrodes distributed over the entire ventricular epicardium. The electro‐grams are recorded and converted to digital form for computer generation of isochronous maps. Maps of the epicardial activation sequence derived from the sock electrode were compared to those obtained by the hand‐held electrode in six normal dogs during sinus rhythm and ventricular pacing. The sequence of local activation times acquired by both methods showed similar areas of early and late activation and comparable isochronous maps. The hand‐held electrode technique required 10–15 minutes for data acquisition and another 15–30 minutes for analysis. The sock electrode array allowed electrograms from 26 epicardial electrodes to be recorded simultaneously during one cardiac cycle and computer generated isochronous maps could be displayed within 10 minutes. This method allows rapid recording and analysis of epicardial electrical phenomena and should meet the time constraints imposed during the intraoperative study of ventricular tachyarrhythmias in patients.
Potential Causes of Spurious Programming: Report of a Case
Authors: SINNAEVE ALFONS , PIRET JOHAN , STROOBANDT ROLAND
Published: July 2006

The possibility of false or inadvertent reprogramming increases with the availability of different and more complex programming mechanisms. A case of spurious programming during application of the Vitatron MPA1 analyzer to a Medtronic impulse generator (IPG) is described and the nature of the phenomenon is explained. It is concluded that the introduction of a simple and standardized “security‐maneuvre” to which every IPG will respond safely, in the event of fortuitous dysprogramming, is required.
Longevity Comparisons Among Lithium Anode Power Cells for Cardiac Pacemakers
Authors: HURZELER PHILIP , MORSE DRYDEN , LEACH CHARLES , SANDS MILTON J. , PENNOCK RONALD , ZINBERG ALLAN
Published: July 2006

Of over 10,000 lithium‐powered pacemakers followed by a commercial franstelephone monitoring service, 148 have been explanted due to rate decline. A breakdown according to the power cell manufacturers shows that the longevity is not uniform, indicating that significant differences exist among the power cell designs even though all have lithium anodes. One tenth of all lithium‐powered pacemakers in the study were explanted for rate declines within 4 years.
An Experimental Method for Thermal Control of Heart Rate: Work in Progress
Authors: PARSONNET VICTOR , DRILLER JACK , HUDSON PETER , VILLANUEVA ALEXANDER , ROUGH WILLIAM , DICK LEON
Published: July 2006

Evaluation of the postoperative course of coronary artery bypass patients shows that a number develop supraventricular arrhythmias that may be responsive to sino‐atrial node (SAN) cooling. The sinus rate can be controlled within a clinically useful range with topical cooling probes (thermodes). The data on the variations of heart rate caused by modest nodal hypothermia indicate that a non‐pharmacologic clinical system for control of supraventricular tachyarrhythmias is feasible. Prototype thermodes suitable for SAN implantation have been developed.
Computer‐Assisted Reporting System for the Follow‐up of Patients with Cardiac Pacemakers
Authors: MacGREGOR DAVID C. , COVVEY H. DOMINIC , NOBLE EDWARD J. , SMARDON SUSAN D. , WILSON GREGORY J. , GOLDMAN BERNARD S. , WIGLE E. DOUGLAS
Published: July 2006

The implantation of large numbers of permanent cardiac pacemakers carries with it the responsibility for continual reassessment of all aspects of patient management. Experience with more than 4,000 pacemaker implants and replacements since 3963 has led to the development of a comprehensive computer‐assisted data collection, management, and reporting system for the follow‐up of patients with cardiac pacemakers. Over a seven‐year period, data forms have been developed for the detailed documentation of pre‐operative, intraoperative and follow‐up information. These were designed in the form of checklists suitable for direct computer entry using mark‐sense document readers. Special emphasis has been placed on pre‐operative indications, selection of appropriate pacing systems, reliable follow‐up methodology, and monitoring the performance of various pulse‐generators. This system makes possible the rapid computer production of hospital records and reports to involved physicians and can be used to schedule follow‐up assessments as required. The information also can be used for hospital statistics, billing, research, and pacemaker registration at the provincial, slate or federal level. Experience has shown that a computer‐assisted methodology is the only practical means of providing adequate follow‐up for a large group of patients. In addition, direct access to relevant information helps to create an environment in which essential research can be carried out in the face of demanding clinical practice.
Severe Conduction Disturbances and Ventricular Arrhythmias Complicating Mediastinal Irradiation for Hodgkin's Disease: A Case Report
Authors: MARY‐RABINE L. , WALEFFE A. , KULBERTUS H.E.
Published: July 2006

A 27‐year‐old male had undergone mediastinal and retroperitoneal iradiation for stage IIIA Hodgkin's disease at age 19. When he was admitted to the hospital, because of lightheadedness and syncope, trifascicular bundle branch block was noted and the patient underwent a clinical electrophysiological investigation. AH and HV intervals were prolonged and ventricular fibrillation was induced during programmed right ventricular stimulation. Serial electrophysiological studies allowed us to prescribe effective antiarrhythmic drug therapy with no recurrence of symptoms during a follow‐up period of 12 months.
Clinical Evaluation of Atrial Synchronous Ventricular Inhibited Pacemakers
Authors: KRUSE IB , RYDÉN LARS , DUFFIN ED
Published: July 2006

The technical specifications and (he operation of two atrial synchronous venfricular inhibited (ASVIP) pacemaker designs ore described along with the results of climcal evaluation of these pacemakers in 30 patients. Clinical advantages of such pacemakers are contrasted with the performance of A‐V sequential (DVI) and atrial synchronous (VAT) systems.
T Wave Sensing with a Programmable Pacemaker
Authors: HERMAN NEIL D.
Published: July 2006

A patient with a recency implanted programmable pacemaker presented with slowing of the pacemaker discharge rate. At all programmed rates the cycle length of pacing was equal to the programmed cycle length plus the interval from pacing artifact to the midpoint of the T wave. Recordings from the implanted electrode documented thai the amplitude of the T wave beyond the refractory period of the pacemaker was still sufficient to recycle the pacemaker.
Failure to Predict Development of Atrioventricular Block with Electrophysiological Testing Supplemented by Ajmaline
Authors: McKENNA WILLIAM J. , ROWLAND EDWARD , DAVIES JOHN , KRIKLER DENNIS M.
Published: July 2006

Electrophysiologoical tesls supplemented by pharmacological stress of atrioventricular conduction with ajmaline failed to predict the development of atrioventricular block in a patient with bifascicular block and no organic heart disease.
Incessant Reciprocating Atrioventricular Tachycardia
Authors: BRUGADA PEDRO , VANAGT EDDY J. , BAR FRITS W.H.M. , WELLENS HEIN J.J.
Published: July 2006

The case of a patient suffering from incessont supraventricular tachycardia is presented. The electrophysiological sludy showed the presence of an accessory atrioventricular (A‐V) bundle with nodal‐like properties and long conduction times. This structure was used as the retrograde arm of the tachycardia circuit. Tachycardia was intermittent at rest, but had a sustained character during slight exercise. Administration of atropine and isoproterenol failed to sustain the arrhythmia and spontaneous initiation during sinus rhythra was no longer observed. During handgrip exercise a sustained tachycardia developed immediately. During ventricular stimulation a duol atrial response to a single paced ventricular premature beat was repeatedly observed, proving the avoilability of two separate A‐V pathways for retrograde conduction. The case illustrates the labile nature of this type of accessory pathway, and suggests that autonomic changes can play an important roJe in the initiation. mainlenance, termination. or even spontaneous cure of tachycardia in patients with this anomaly.
Modification of Myocardial Test Probe for Epicardial Pacemaker Insertion
Authors: SNOW NORMAN
Published: July 2006

Modification of the myocardial test probe has proven voluable in reducing the danger of myocardial laceration and has improved the reliability of epicardial threshold measurements during epicordial pacemaker insertion. Angulation of the stylet to 30° and 60° allows application of the probe at an angle perpendicular to the epicardial surface of the heart, thus reducing readoul variotion and epicardiaJ trauma.
Nondestructive Determination of Pacemaker Sense Amplifier Passband
Authors: DALY DAVID
Published: July 2006

Most artificial cardiac pacemakers incorporate sense amplifiers to detect intrinsic heart activity in order to eliminate the possibility of competition between the artificial and natural pacemakers. When artificial pacemakers fail prematurely, the failure cause should be determined so that systematic failure modes can be identified and corrected. The failure analysis of any sophisticated electronic product is difficult; failure analysis of a cardiac pacemaker is complicated by the sealing technologies encountered. Because access to the circuitry of implantable devices is impeded by the packaging of the device, and because the packaging may have influenced the failure, nondestructive testing techniques must be used extensively. This paper reports on a method for nondestructive determination of the pacemaker sense amplifier with a (sin x)/x waveform to which a continuous wave sinusoid is added. The amplifier passband is characterized by increasing the frequency of the sinusoid in increments of 5 Hertz and determining the amplifier sensitivity at each step.
Second and Third Degree Atrioventricular Block with Graves' Disease: A Case Report and Review of the Literature
Authors: MILLER RONALD H. , CORCORAN FRANCIS H. , BAKER WILLIAM P.
Published: July 2006

A previously healthy woman experienced Adams‐Stokes attacks ten weeks after the initiation of antithyroid medication for Graves' disease. The patient manifested advanced atrioventricular (A‐V) block requiring a temporary transvenous pacemaker. The site of heart block was localized to the A‐V node by utilizing a His bundle electrogram. With control of the hyperthyroid state, normal A‐V conduction was restored. Review of the literature identified twenty‐five additional cases of second or third degree A‐V block associated with Graves' disease, ten of whom had Adams‐Stokes syncope or convulsive seizures. The A‐V nodal block was reversible with cure of the primary endocrine disease. It is postulated that excessive thyroid hormone has a direct effect on the cardiac conduction system, specifically, the region of the A‐V node and bundle of His. Recommendations are made regarding the recognition and management of patients at risk for developing heart block associated with Graves' disease.
TQ Segment (Baseline) Alternans during PrinzmetaPs Variant Angina
Authors: ROZANSKI JOHN J. , KLEINFELD MORRIS
Published: July 2006

In a study of 93 patients who met criteria for Prinz‐metal's angina, alternans of the ST segment was observed in 28 of 93 patients (30%), In 8 of these 28 patients, a hitherto undescribed variant of alternans, namely alternation (≥1 mm shift in 2:1 pattern) in the amplitude of the baseline or TQ segment (TQ AI) was observed. In all eight patients serious ventricular arrhythmias were noted, namely, ventricular fibrillation in two, ventricular tachycardia in four, and multiform or advanced ventricular ectopic activity in eight. The TQ All developed only after ST segment alternans occurred. It is postulated that the alternations of the ST and TQ segments are due to differences in current flows due lo inhomogeneity of depolarization and repolarization of the action potential caused by ischemia. Furthermore, the associated arrhythmias observed are related to the inhomo‐geneous state initiated by the ischemia.
Intermittent and Arrhythmic “Runaway” Pacemaker
Authors: SANTINI M. , MESSINA G. , MASINI V.
Published: July 2006

An unusual case of intermittent and arrhythmic runaway pacemaker is described. The malfunction was detected during implantation, at which time it caused ventricular fibrillation in the patient in whom it was implanted. The authors wish to emphasize the necessity of accurate pacemaker testing in the factory and the operating room, and to stress the importance of manufacturing pacemakers unable to emit a high number of impulses, even in the presence of a faulty circuit component.
Electrical Alternans of the ST Segment in Non‐PrinzmetaPs Angina
Authors: DEMIDOWICH GEORGE , WERRES ROLAND , ROTHFELD DONALD , BECKER JULIE
Published: July 2006

Elevated electrical alternans of the elevated ST segment (STEA) was documented in a patient with non‐Prinzmetal's or classical angina and severe atherosclerotic coronary artery disease. STEA was precipitated during graded exercise testing. The disappearance of this phenomenon after aortocoronary bypass surgery suggests that the coronary obstructions were the etiologic factors. These findings emphasize that the STEA may occur in myocardial ischemia caused by conditions other than Prinzmetal's angina.
Exit Block in Myxedema, Treated Effectively by Thyroid Hormone Therapy
Authors: SCHLESINGER ZWI , ROSENBERG THOMAS , STRYJER DOV , GILBOA YGAL
Published: July 2006

A case of a 71‐year‐old female who developed exit block one year after implantation of a pervenous pacemaker is reported. The pacemaker had been implanted for sick sinus syndrome; the exit block was probably due to the development of severe myxedema which caused high pacing threshold. Normal pacing threshold was obtained on the seventh day of adequate thyroid hormone therapy and a follow‐up one year later revealed effective control of the myxedema and no abnormalities in the function of the pacemaker system.
Electrophysiologic Properties of Cimetidine in Man
Authors: GOULD LAWRENCE , REDDY C.V. RAMANA , SINGH B.K. , ZEN B.
Published: July 2006

Severe brady‐cardia has been reported with the use of cimetidine.1–5 This observation has been explained by histamines' known action in increasing the contraction rate of the spontaneously beating right atrium, strips of ventricular muscle, and whole heart of guinea pigs.6 Histamine can also produce cardiac arrhythmias in animals.7 There is evidence for H2 receptors in the heart. Black and his associates8 have shown that the characteristic effect of histamine on isolated guinea pig atrium could be selectively blocked by anti‐H2 drugs. Thus cimetidine probably can produce a sinus brady‐cardia by blocking the H2‐receptor site in the heart. Recently Engel and Luck9 reported that 300 mgs of intravenously administered cimetidine did not affect heart rate, sinus node recovery time, or sinoatrial conduction time. These workers concluded that there is insufficient evidence to demonstrate that cimetidine causes appreciable sinus node dysfunction in man. In view of the disparity in these reports, we investigated the effects of 300 mgs of intravenously administered cimetidine on the human conduction system.
Long‐Term Follow‐up after Pacemaker Implantation in Sick Sinus Syndrome
Authors: van HEMEL N.M. , van RIEMPST A.L.E. SGHAEPKENS , BAKEMA H. , SWENNE C.A.
Published: July 2006

In 74 symptomatic patients suffering from sick sinus syndrome, sur‐vival after pacemaker implantation and additional drug therapy was determined. The 5‐year survival was poor (47.2%). Evidence of other cardiac disease (present in 44.6%) influenced the prognosis unfavorably, especially in combination with con‐tinuing symptoms. As yet the phase of SSS in which chronic cardiac pacing is re‐quired, should be considered as a critical stage.
Computer Quantitated Evaluation of Cardiac Arrhythmias
Authors: ATTUEL P. , ROSENGARTEN M. , LECLERCQ J.F. , MILOSEVIC D. , MUGICA J. , COUMEL Ph.
Published: July 2006

The identification of a cardiac arrhythmia depends on the interpretation of both the QRS complexes and the P waves. P wave detection is unreliable and hence automated diagnostic systems are often imperfect. An alternative is a system which detects QRS only and which classifies the QRS events; the physician then has a detailed quantitated QRS analysis to aid in diagnosis. The ATREC system has an analog QRS detector, which suppresses the P wave and the T wave frequencies and feeds a minicomputer (Mitra 15/35) with signals for the RR interval, the QRS duration, and polarity. The computer classifies these signals as either narrow or wide complexes. The narrow complexes are analyzed for irregular rhythm, bradycardia, pauses, transient or continuous tachycardia, and fibrillation. The wide complexes are classed by their coupling interval, bi‐ or trigeminy, doublets, or salvos, and the number per hour. The system gives a trend of the 16 beat mean, and the minimum and maximum heart rate. The data is presented on several displays.
A Variation on the Introducer Technique for Unlimited Access to the Subclavian Vein
Authors: BELOTT PETER H.
Published: July 2006

An adaptation of the sheath set approach for permanent trans‐venous electrode placement has been carried out in fifteen patients. At the time of lead insertion, the sheath guide wire is left in pface. If a second lead is desired or lead exchange becomes necessary, a second sheath is applied to the retained guide wire and a new lead inserted, thus avoiding a second subclavian puncture or new venous cutdown. This in effect offers a limitless access to the central venous system as long as the guide wire is left in place. This adaptation is especially suited for dual chamber pacing, where multiple leads may be required.
Transient Early T Wave Sensing by Implanted Programmable Demand Pulse Generator
Authors: BAROLD S. SERGE , YOKOYAMA MASAYOSHI , WADA JURO , BAROLD S. SERGE
Published: July 2006

A seven‐year‐old girl with a permanent epicardial programmable pulse generator developed inappropriate slowing of the pacing rate due to oversensing a combination of T wave and afterpotential valtage. This phenomenon occurred only in the first three days after implantation and was demonstrable only at long programmed pulse widths. Our observations suggest that the current of injury in the early post‐operative period may generate a relatively high T wave voltage capable of combining with a large afterpotential to produce a signal exceeding the sensitivity of a demand pulse generator.
Comparison of Active and Passive Leads for Endocardial Pacing—II
Authors: Sloman Graeme , FURMAN SEYMOUR , PANNIZZO FRANK , CAMPO IVON
Published: July 2006

Four commerciaily available fransvenous pacing leads were evaluated in a series of 240 implanfs on a rotalional order basis. Total (in‐tra‐ and post‐operative) failure rates for this series were: Cordis 1 mm, 1/60 (1.7%); Biotroniik IE‐65‐I, 5/60 (8.3%); Medtronic 6961, 4/60 (6.7%); and CP1 4316, 6/60 (10.0%). Post‐operative faiJure rates were: l mm, 1/60 (1.7%); IE‐65‐1, 4/59 (6.8%); 6961, 0/56 (0.0%), and 4116, 3/57 (5.3%). In a previous study conducted at this center with identical protocol, total failure rates were: Medtronic 6907, 7/76 (9.2%); Cordis CL, 7/76 (9.2%); Biotronik IE‐65‐I, 2/76 (2.6%); and the Vitatron MIP‐2000, 9/45 (20.0%). Post‐operotive failure rates were: 6907, 4/73 (5.5%); CL, 6/75 (8.0%); IE‐65‐I, 2/76 (2.6%); and MIP‐2000, 5/41 (12.2%). If the two IE‐65‐1 series are combined, the totaJ faiJure rate is 7/136 (5.1 %), and the post‐operative failure rate is 6/135 (4.4%). Significant differences exist between the highest and lowest failure rates in total and post‐operative cases for each series. The final decision concerning use of a par‐ticular lead must, of course, be based on clinical criteria.
Serial Electrophysiological Studies in a Young Patient with Recurrent Ventricular Fibrillation
Authors: BELHASSEN B. , PELLEG A. , MILLER H.I. , LANIADO S.
Published: July 2006

A 28‐year‐old male with recurrent episodes of ventricular fibrillation, which were initiated by very early ventricular premature depolarizations with a normal QT interval, was subjected to three consecutive electrophysiological studies. During the first study, which was carried out to test the efficacy of amiodarone treatment, no ventricular arrhythmias could be induced. While on amiodarone therapy, the patient experienced another syncopal episode and therefore a second electrophysiological study was done. In that study, ventricular fibrillation was induced by ventricular stimulation. During the third study, which was carried out in order to evaluate the effect of the addition of quinidine to the ongoing amiodarone therapy, no more than three repetitive ventricular responses could be induced. The patient has been asymptomatic since the third study (fifteen months) with combined therapy of amiodarone and quinidine. The significance of the ability to induce ventricular fibrillation during an electrophysiological study is discussed as well as the value of such studies in determining the long‐term efficacy of antiarrhythmic drug therapy.
Continuous On‐Line Beat‐to‐Beat Analysis of AV Conduction Time
Authors: WAXMAN MENASHE B. , WALD ROBERT W. , MCGILLIVRAY RICHARD , CAMERON DOUGLAS A. , SHARMA ARJUN D. , HUERTA FELIX
Published: July 2006

A simple analog circuit is described which is capable of measuring on a beat‐to‐beat basis P‐R, R‐P, P‐P, and R‐R intervals during sinus rhythm and paroxysmal supra ventricular tachycardia. In addition the circuit will emit a pulse when the consecutively alternating P and R wave sequence is interrupted thereby signalling a trigger problem or a change in rhythm. The operation of the device requires proper P and R wave sensing and provides outputs which are linear over a range of rates which are applicable to the human heart.
Noninvasive Recording of the His Bundle Electrogram: Value of Supplementary Verapamil
Authors: MCKENNA WILLIAM J. , ROWLAND EDWARD , MORTARA DAVID , DIVERS THOMAS , KRIKLER DENNIS M.
Published: July 2006

We obtained nom'nvasive recordings of the His bundle electrogram using the Marquelte high resolution MAC unit in 65 patients and 5 normal subjects. Overlap of atrial activity prevented identification of G His potential in 25 subjects, in 23 of whom the PR interval was equal to or less than 160 ms, After intravenous verapamil (10 mg) the AH interval was lengthened, with an increase in the PR interval of 10–60 (mean 20) ms, A characteristic His bundle electrogram was recorded in 48 of the 70; in 8 there was persistent atrial activity and in 4 electrical interference could have obscured a His potential, In 10 patients the absence of a His complex despite a clear “window” of at least 70 ms between the end of atrial activity and the onset of ventricular depolarization suggested that its vector was outside the plane of the electrode arrangement, or that there was a prolonged H‐V interval; the latter has been confirmed in 2 patients. Intracardiac His bundle recordings in 25 subjects who had characteristic surface electrical activity of the His bundle disclosed good correlation between invasive and noninvasive measurements of the H‐V interval. This noninvasive technique using portable equipment, which permits serial evaluation of the His bundle electrogram, may facilitate prospective studies in patients with conduction disease.
Electrical Alternans of Pacemaker Spike Amplitude: an Unusual Manifestation of Permanent Pacemaker Generator Malfunction
Authors: AUSTIN STEPHEN M. , KIM CHUNG S. , SOLIS ARIEL
Published: July 2006

A case of electrical alternans of pacemaker stimulus amplitude is presented, with constant alternation of large and small amplitude pacemaker spikes without loss of ventricular capture, due to a defect in the oscillator hybrid of a rate programmable Medtronic unit. This represents an unusual electrocardiographic manifestation of pacemaker generator malfunction which, to our knowledge, has not been reported previously.
Congenital Absence of Superior Vena Cava: Unusual Anomaly of Superior Systemic Veins Complicating Pacemaker Placement
Authors: HUSSAIN S. AMJAD , CHAKRAVARTY SUPRIYA , CHAIKHOUNI AMER , SMITH J.R.
Published: July 2006

Congenital anomalies of the superior systemic veins can complicate placement of transvenous pacemaker electrode leads. Persistent left superior vena cava is the most common congenital anomaly; in this paper, we describe the case of a patient who had con‐genital absence of both superior venae cavae, which has not been reported pre‐viously. The superior syslemic veins drained into persistent double ozygos veins subdiaphragmatically. The anomaly was verified by venography. Temporory car‐dioc pacing was established by passing the electrode lead through the femoral vein, and a permanent epicordial pacemaker lead was placed thereafter. This appears to be the first recorded case of such an anomaly.
Transient Entrainment and Interruption of Ventricular Tachycardia
Authors: MACLEAN WILLIAM A.H. , PLUMB VANCE J. , WALDO ALBERT L.
Published: July 2006

The effects on spontaneously occurring ventricular tachycardia of rapidly pacing the right ventricle at rates faster than the rate of the ventricular tachycardia were studied during 10 episodes in seven patients. In three episodes, ventricular pacing interrupted the ventricular tachycardia at the initial pacing rate (111%, 114%, and 119% of the ventricular tachycardia rate, respectively). In seven episodes, the initial pacing rate failed to interrupt the ventricular tachycardia. In six of those seven episodes, the ventricular tachycardia was transiently entrained to the faster pacing rates, in one of those seven episodes, transient entrainment of the ventricular tachycardia could not be distinguished from overdrive suppression. In all seven episodes, the tachycardia was Jater interrupted by pacing at more rapid rates. The successful pacing rate ranged from 111–141% (mean 125%) of the spontaneous ventricular tachycardia rate. It is concluded that when utilizing rapid ventricular pacing to interrupt ventricular tachycardia, a critical pacing rate may be required before interruption is achieved. Pacing at rates slower than the critical rate but faster than the spontaneous ventricular tachycardia rate may only transiently entrain the ventricular tachycardia to the pacing rate without interrupting it. During the period of transient entrainment, fusion QRS complexes are likely to be present.
An Evaluation of Long‐term Stimulation Thresholds by Measurement of Chronic Strength Duration Curves
Authors: HYNES JOHN K. , HOLMES DAVID R. , MERIDETH JOHN , TRUSTY JANE M.
Published: July 2006

Successful long‐term cardiac pacemaker therapy requires both reliable generator output and stable, altainable chronic stimulation thresholds. Strength duration curves, which display cardiac stimulalion thresholds as a function of impulse duration, provide needed data to evaluate more thoroughly acute and chronic lead thresholds. We measured chronic strength duration curves at the time of generator replacement in 47 patients with three different types of lead systems of variable geometry and surface area and compared these curves with acute strength duration curves measured at the time of initial lead implantation in 19 patients. We found that strength duration curves have a characteristic shape; however, chronic strength duration curves were shifted upward and to the right of acute strength duration curves, regardless of electrode tip surface area or geometric design. Our data suggest that variable pulse width exceeding 1 ms may not significantly reduce stimulation thresholds.
A New Code for Pacemaker Operating Modes
Authors: BROWNLEE R.R. , SHIMMEL J.B. , DEL MARCO C.J.
Published: July 2006

A new code is proposed that can be used as a supplement to the ICHD code to describe single‐ and dual‐chamber pacemaker operating modes. The code visually jndicates the chamber(s) involved by means of a common base‐line with indicators for atrial activity above and ventricular activity below. Letter indicators are used. For single‐chamber units, on O represents the chamber in which no pacemaker activity occurs. P represents pacing, S sensing, IA inhibition by a sensed atrial event, Iv inhibition by a sensed ventricular event, TA triggering by a sensed atrial event, and tv triggering by a sensed ventricular event. For example, o pacemaker mode described as PSIAJvJPSTAIv paces and senses both chambers; inhibits atrial pacing by a sensed event in either chamber; inhibits ventricular pacing by a sensed ventricuiar event but triggers ventricuiar pacing, after an assumed A‐V delay, by a sensed atrial event. Thus even the most complex modes of pacing operation can be clearly and accurately described by means of this new code. Especially useful in teaching applications is the distinction of acfivity by chamber and the description of response in one chamber to activity in the other.
Comparison of a Porous‐Surfaced with a Totally Porous Ventricular Endocardial Pacing Electrode
Authors: BOBYN J. DENNIS , WILSON GREGORY J. , MYCYK TARAS R. , KLEMENT PETER , TAIT GORDON A. , PILLIAR ROBERT M. , MacGREGOR DAVID C.
Published: July 2006

Porous endocardial ventricular electrodes, re‐cent innovations in cardiac pacing technology, have been shown to perform in a su‐perior manner compared to conventional solid electrodes with respect to such parameters as stimulation threshold, sensed R‐wave amplilude, and source im‐pedance, This experimental study compared the electrophysiological performance of a porous‐surfaced and a totally porous electrode, two fundamental design vari‐ations of the porous eJectrode concept which are in current clinical use. Six porous‐surfaced (1 mm length, 2.3 mm diameter, 8.8 mm2 outer surface area, pores < 25 μn) and six totally porous (1.3 mm length, 2.0 mm diameter, 7,5 mm‐ outer surface area, pores 100 to 150 μm) flanged ventricular endocardial eleclrodes were implanted into the right ventricular apex of 12 dogs. Stimulation threshoids under constant current and constanl voltage conditions at pulse durations of 0.1, 0.25, 0.5, 0.75, 1.0, 1.5, and 2.0 milliseconds, sensed peak‐to‐peak R‐wave amplitudes, and source impedance ivere measured at implant and at l, 4, 8, 12,16, 24, and 30 weeks (explant) thereafter. Analyses of voriance on the data for the strength‐durolion curves at expiant and the threshold‐time curves at l ms pulse duration indicated highly significant differ‐ences between the performance of the two types of electrodes, the porous‐surfaced electrodes displaying average Stimulation threshoids approximateiy 30% lower than the totally porous electrodes. Student's t tests indicated the magnitude of the sensed R‐wave to be maintained over the 30 week period for the porous‐surfaced electrodes but to decrease by about 20% for the totally porous electrodes. In addition, the chronic source impedance of the porous‐surfaced electrodes was significtmtly Jess (about 257%) than that of the totally porous electrodes. These differences indi‐cate better overall electrophysiological performance for the porous‐surfaced electrodes as compared with the totally porous electrodes. Both types of electrodes, however, operate well within the limits of highly acceptable function and therefore rep‐resent attractive designs for clinical use in endocardial pacing.
Initial and Early Follow‐up Assessment of the Clinical Efficacy of a Multiparameter‐Programmable Puise Generator
Authors: HAYES DAVID L. , MALONEY JAMES D. , MERIDETH JOHN , HOLMES DAVID R. , GERSH BERNARD , BROADBENT JAMES C. , OSBORN MICHAEL J. , FETTER JOSEPH
Published: July 2006

Recent advances in pacemaker technology have produced noninvasively multiparameter‐programmable puise generators that have the potential for resolving complications that result from the pacing system and forproviding a mechanism whereby adjustments can be made for the specific needs of a patient without corapromising reliability and longevity. These applications were assessed by analyzing the initial indications, clinical efficacy, and reliability in 100 consecufive patients who received a multiparameter‐program‐mable puJse generator. Data analysis showed that 78% of the 100 patients had changes in rate programmed, 16% in pufse width, and 5% in sensitivity. Program‐mability was utilized for voJtage amplitude (one patient) but was not utilized for hysteresis and refractory period. Although progrtimming changes (rate and pulse width) generally could have been accomplished with simpler units, program‐mability for sensitivity made it possible to solve pacemaker problems in five patients and clearly eliminated the need for reoperation in two patients. The compact size of the multiparameter‐programmable pulse generator has allowed its use in patients in the pediatric age group, patients with a small frame, and patients with a major concern about cosmetic appearance. Programming sensitivity for proper sensing of the atrial signal allows use of the multiparameter‐programmable pulse generator as an atrial pacemaker. This was done in one pediatric patient who also benefited from suppression of atrial overdrive. There have been no episodes of spurious programming. Reliabitity has not been sacrificed by the increased complexity of this unit. If preimplant criteria for use of a multiparameter‐program‐mable puise generator are too sfrict, this may limit its potential therapeutic value because the need for its flexible characleristics is unpredictable.
An Indication for His Bundle Study: Syncope, a Normal P‐R Interval and a Narrow QRS
Authors: LISTER JOHN W. , IESAKA YOSHITO , PINAKATT THERESA , GOSSELIN ARTHUR J.
Published: July 2006

This report describes a patient who presented with transient central nervous system symptoms of unknown etiology with an electrocardiogram exhibiting a narrow QRS complex and normal P‐R interval. The decision to implant a permanent VVI pacemaker was made on the basis of a His bundle study that revealed significant prolongation of the HV interval. The successful clinical outcome re‐emphasizes the clinical usefulness of electrophysiologicol investigation in patients with syncope of undetermined etiology.
A New Temporary Atrial Pacing Catheter Inserted Percutaneously into the Subclavian Vein Without Fluoroscopy: A Preliminary Report
Authors: SLOMAN GRAEME , LITTLEFORD PHILIP O. , PEPINE CARL J.
Published: July 2006

A permanently formed “J” shaped 6F bipolar electrode catheter specially designed to facilitate temporary atrial pacing was constructed and tested in 15 patients. A pair of rigid, “orienting wings” was fixed to the catheter 28 cm from a large spherical tip electrode to establish directional orientation of the “J” while in the right atrium, Rapid percutaneous introduction is possible with a peel‐away sheath via the subclavian vein. Positioning in the right atrium can be accomplished without fluoroscopy. The catheter could be inserted and positioned against the right atrial wall generally in less than three minutes and required little or no additional manipulation for capture. No instance of loss of capture was documented during subsequent continuous monitoring as the catheter remained in place from one to thirteen days, Ease of insertion of this electrode catheter, as well as stability, provided an effective method for temporary atrial pacing without fluoroscopy. This novel catheter design warrants testing in a large patient population by others and could have potential application to other types of catheter needs.
The Case of the Two‐timing Pacemaker
Authors: COMER THOMAS P. , SAXENA NARESH , SALZMAN STEPHEN H.
Published: July 2006

A 71‐year‐old man with a permanent transvenous pacmaker had recent history of lightheadedness and was brought to the hospital emergency room com‐plaining of shortness of breath. His blood pressure was 80/50, pulse rate 148. Administration of a pressor drug restored blood pressure and coincidentally the heart rate returned to 70. His condition was caused by formation of a dendritic spur in the substrate of the programming circuit in his implanted pacemaker, with consequent intermittent doubling of the impulse frequency. Another pacemaker was substituted surgically, and he recovered uneventfully.
Pacemaker Malfunction Following Transthoracic Countershock
Authors: DAS GOPAL , EATON JOHN
Published: July 2006

Electrical cardioversion or defibrillation may be necessary in patients with implanted artificial cardiac pacemakers. Sudden discharge of high electrical energy employed in DC transthoracic countershock procedures may damage the sensitive pacemaker circuitry and result in malfunction. We report a case in which, following synchronized DC countershock, a non‐programmable demand pacemaker functioned in the R‐wave triggered mode rather than the R‐wave inhibited mode as designed. Further, the pacemaker output voltage was reduced to about half its specified output. Such a malfunction may not be readily apparent, and requires careful analysis following electric shock. (PACE, Vol. 4, September‐October, 1981)