bluuebunny/crossref_metadata_2025 huggingface dataset:
Congenital Swallowing‐induced Symptomatic Heart Block: A Case Report of a Probably Hereditary Disorder
Authors: GOLF SVEIN , FORFANG KOLBJØRN
Published: July 2006

A 15‐year‐old girl had had syncope induced by swallowing since infancy. An ECG recorded during food intake revealed SA block with very slow functional and ventricular escape rhythms. No symptoms or signs of other cardiac disorders or gastrointestinal diseases were present. Activation of a strong vagal reflex, able to inhibit impulse formation and propagation in an otherwise normal heart, is the most likely explanation of the disorder in this patient. Furthermore, EGGs of her close relatives which were recorded during food intake as compared with the findings in a reference group (n = 20), indicated that a genetic factor could be involved.
The Salvage of Infected Cardiac Pacemaker Pockets Using a Closed Irrigation System
Authors: HURST L.N. , EVANS H.B. , WINDLE B. , KLEIN G.J.
Published: July 2006

Over a period of 71 months, 19 patients were treated for infected or eroded permanent pacemaker pockets. All cases were treated with local debridement and insertion of a closed irrigation system using a solution of tyloxapol and tobramycin. Successful eradication of the infection, without complete replacement of the pacemaker system, was achieved in all cases.
Long‐Term Management of Ventricular Tachycardia by Implantable Automatic Burst Tachycardia‐Terminating Pacemakers
Authors: FALKOFF MICHAEL D. , BAROLD S. SERGE , GOODFRIEND MICHAEL A. , ONG LING S. , HEINLE ROBERT A.
Published: July 2006

This report describes the Jong‐term follow‐up of two patients who received implantable automatic burst tachycardia‐terminating ventricular pacemakers for the treatment of drug‐refractory sustained ventricular tachycardia. After implantation, both pulse generators continued to terminate ventricular tachycardia without any major complications. In one patient, after three years, many episodes of ventricular tachycardia were slower than the tachycardia‐detection criterion rate of 137 per minute; ventricular tachycardia was then terminated by chest wall stimulation that activated the burst function of the pacemaker. In this particular patient, the pulse generator was removed after four and one‐half years and replaced with a DDD system because of the pacemaker syndrome and attacks of ventricular tachycardia, often at a rate of about 100/minute. In the second patient, the pacemaker continued to terminate ventricular tachycardia for over five and one‐half years as determined by the repeated activation of the flag (memory) function of the pacemaker indicating detection of tachycardia by the pulse generator and resultant delivery of burst pacing.
Sudden Cardiac Death in a Southeast Asian Immigrant: Clinical, Electrophysiologic, and Biopsy Characteristics
Authors: GILBERT JON , GOLD ROBERT L. , HAFFAJEE CHARLES I. , ALPERT JOSEPH S.
Published: July 2006

The syndrome of sudden cardiac death in southeast Asians has only recently been given attention in the American medical literature. This case report describes a patient who presented with this rare syndrome. The physical examination, Holter monitor. 2‐D echocardiogram, exercise treadmill test, radionuclide ventriculogram, coronary angiography, and endomyocardial biopsy were all normal. Programmed ventricular stimulation reproducibly induced sustained polymorphic ventricular tachycardia, Oral procainamide, oral quinidine and oral quinidine plus propranolol were not successful in suppressing inducible polymorphic ventricular tachycardia. The arrhythmia remained inducible after six weeks of oral amiodarone therapy. However, he has had no clinical recurrences while on amiodarone after one year of follow‐up.
Reliability of Evoked Endocardial T‐wave Sensing in 1,500 Pacemaker Patients
Authors: BOUTE W. , DERRIEN Y. , WITTKAMPF F.H.M.
Published: July 2006

Intracardiac measurements of the evoked endocardial T‐wave were performed on 1,500 pacemaker patients. The sensed evoked T‐wave amplitude was found to be above 0.75 mV in 94.1 percent of all cases. No correlation was found between the amplitude of the spontaneous R‐wave and that of the evoked T‐wave. Some electrode characteristics proved to be more favorable than others for evoked endocardial wave sensing, i.e., a surface area of less than 12 mm2. porous surface structure (preferably carbon), and atraumatic fixation.
Electrode Configurations for a Respiratory Impedance Measurement Suitable for Rate Responsive Pacing
Authors: NAPPHOLTZ TIBOR , VALENTA HARRY , MALONEY JAMES , SIMMONS TONY
Published: July 2006

A rate responsive cardiac pacemaker will benefit the patient only if the input parameter is a reliable indicator of exercise, Part of the reliability is dependent upon selection of the best physiological parameter and part is dependent upon the measurement technique. Twenty‐six patients have been studied in order to ascertain the best measurement configuration for an intravascular impedance respiratory monitor. Four electrode configurations have been examined at rest and during exercise. The results have been compared using measures of sensitivity and specificity. The ideal configuration requires that a current field be established between the right ventricular blood and the pacemaker case. And, that voltage sensing be done between an electrode in the SVC and the pacemaker case.
Clinical Experience with an Activity Sensing Pacemaker
Authors: LINDEMANS FRED W. , RANKIN IAN R. , MURTAUGH RICHARD , CHEVALIER PETER A.
Published: July 2006

During clinical evaluation of the Medtronic* Activitrax pacemaker in a worldwide multicenter study, implant and follow‐up data were provided by 61 investigators on 222 patients. Pacing indications included two‐ and three‐degree AV block in 149 and atrial arrhythmias in 174 patients; 16 patients received atrial pacing. Average and longest documented follow‐up periods were 7.5 and 16 months respectively. Paired treadmill tests, one in Activity mode and one in VVI/AAI mode, were performed by 120 patients. At peak exercise, average heart rate was 95 bpm in VVI/AAI mode and 118 bpm in Activity mode (p < 0.0001). Average exercise time was 9.4 minutes in VVI/AAI mode and 10.8 minutes in Activity mode (p < 0.0001). In 54 patients who exclusively had paced rhythm during both treadmill tests, average heart rates and exercise times were 70 ppm and 8.1 minutes in VVI/AAI mode and 111 ppm and 10.3 minutes in Activity mode respectively (p < 0.0001). 24‐hour Holter recordings typically demonstrated pacing at or near basic rate during periods of rest and appropriate increase in pacing rate during daily activities. Patients had significantly fewer problems with physical effort in daily life during a week of Activity mode pacing than during a week of VVI/AAI mode pacing (p < 0.05) as assessed from the symptom scores recorded by 62 patients in special diaries.
Rate Control with an External SO2 Closed Loop System
Authors: STANGL K. , WIRTZFELD A , GÖBL G. , HEINZE R. , LAULE M. , SEITZ K. , LOGHSCHMIDT O.
Published: July 2006

In 20 volunteers (mean age 35.5 y) and 12 pacemaker patients (mean age 68.7 y), central venous oxygen saturation (SO2) was monitored continuously by means of an optical sensor integrated in an external transvenous pacing lead placed in the right ventricular cavity. From the SO2 signal recorded at rest and during various modalities of exercise, an algorithm for controlling pacing rate of an external pacing system was developed. An open loop system was used in the volunteers, allowing the comparison of the computed pacing rate with the individual intrinsic heart rate. There was an excellent correlation between the two frequencies as far as the dynamic characteristics and the steady state relationship were concerned. In five pacemaker patients who were stimulated via the external lead, a closed loop control of pacing rate was used. In one patient with a DDD pacemaker implanted for third degree AV‐block, the rate response of the SO2 driven pacemaker was well in accordance with the rate attained with the implanted atrial triggered system. With both pacing modes, exercise capacity as determined on a symptom limited treodmill test was identical. In four patients (3 AV block III, 1 bradyarrhythmia) an improvement in exercise tolerance up to 65 percent could be demonstrated with the rate responsive pacing mode. In all patients, it could he shown that an autoregulating pacemaker system with SO2 is an open possibility.
Advances in DDD Pacing
Authors: GOLDSCHLAGER NORA
Published: July 2006

Advances in DDD design are increasingly directed toward imitating actual cardiac physiology. Eventually, biosensors will command implanted dual chamber units' responses, affording the most physiologic of circumstances. Since these improved design features are quite complex, the care of the paced patient may well have to be performed in specialized centers. The responsibility thereby incurred mandates to those involved in cardiac pacing critical validation of the actual clinical relevance of newer DDD features.
Complications in Dual Chamber Pacing: A Six‐Year Experience
Authors: MARKEWITZ ANDREAS , HEMMER WOLFGANG , WEINHOLD CHRISTIAN
Published: July 2006

In a six‐year period (1980–1985), 345 dual chamber pacing systems were implanted in our hospital. Intraoperative complications were rare (n = 5/345 = 1.4%). 25 patients (7%) have died, 11 (3%) were lost follow‐up. A total of 39 patients (13%) showed minor problems, which could be overcome by reprogramming. Another 48 complications (15%) required reoperation. Nearly 70% of those reoperations (n = 31/48) were caused by a malfunction of the atrial lead. This high complication rate of 9% related to all implanted atrial leads could be reduced in the last three years to 2%. We could maintain a dual chamber stimulation mode (DDD, DDI, DVI, VDD) in 396 patients (99%). We conclude that improvements in lead design, pulse generator's programmability, and surgical experience have reduced complication rates to acceptable low values. Meanwhile, dual chamber pacing con be considered as safe as single chamber pacemaker therapy.
New Developments for Upper Rate Response in DDD Pacing
Authors: WARREN JAY , BAKER ROSS , FALKENBERG ERIC , SANDERS RICHARD , VANDEGRIFF JOSEPH , CALFEE RICHARD
Published: July 2006

Although widely accepted as an effective method of dealing with rapid atrial rates in a DDD pacemaker, Wenckebach‐type and multiblock‐type upper rate behaviors may exacerbate pacemaker‐mediated tachycardia through AV dissociation. In addition, pathologic atrial rates (e.g., atrial fibrillation, atrial flutter, automatic atrial tachycardia, etc.) frequently result in ventricular pacing at inappropriately high rates. New, more sophisticated algorithms available in today's microprocessor‐based DDD pacing systems provide the capability to discriminate successfully a normal atrial rate response to exercise from a pathologic atrial rate. These and other improved capabilities allow the clinician to provide safe rate‐responsive pacing to patients in whom rate‐responsive pacing was previously contraindicated.
Merits of Various Antipacemaker Circus Movement Tachycardia Features
Authors: DEN DULK KAREL , LINDEMANS FRED W. , WELLENS HEIN J.J.
Published: July 2006

Pacemaker circus movement tachycardia (PCMT) was a significant problem in first generations of DDD pacemakers. Programmability of the atrial refractory period proved to he an elective tool to prevent PCMT except in patients with very long ventriculoatrial (V‐A) conduction intervals, because a long atrial refractory period severely limits the maximum tracking rate. In these patients, extension of the atrial refractory period after a VPB, bipolar atrial sensing, adaptation of atrial refractory period to atrial rate, and VPB synchronous atrial stimulation helped limit the incidence of PCMT. Rate smoothing and fallback behavior have given rise to other forms of PCMT. Once initiated, PCMT can be terminated by a single P wave or by means of an appropriately timed atrial stimulus. Recognition by means of continued upper rate pacing may not be helpful in patients with a long V‐A conduction interval because their PCMT rate will be low, thus requiring a low upper rate to trigger. Therefore, (1) absolute prevention of PCMT has not yet been achieved, but PCMT is no longer a significant problem in DDD pacing; (2) recognition of PCMT should not be related to the ventricular upper rate limit.
Measurement of Differences in Timing and Sequence Between Two Ventricular Electrodes as a Means of Tachycardia Differentiation
Authors: MERCANDO ANTHONY D. , FURMAN SEYMOUR
Published: July 2006

The use of two ventricular sensing electrodes to determine electrical activation sequence could provide a method for differentiation of normal from abnormal rhythms by implantable antitachycardia devices. Simultaneous recordings from two ventricular sites were obtained during dual chamber pacemaker implantation (5/8 patients), cardioverter‐defibrillator implantation (2/8 patients), or programmed electrical stimulation study (1/8 patients). Recordings were made in normal sinus rhythm (NSR) (5 beats each in 8/8 patients), during ventricular tachycardia (VT) (38 beats with 7 morphologies in 3 patients) and during premature ventricular contractions (PVCs) (20 beats with 8 morphologies in 6 patients). Leads were placed transvenously in the right ventricle in 6 patients, and epicardially on the left ventricle in two. Intervals between the intrinsic deflection of the two ventricular electrograms ranged from 0 to 91 ms (mean of 26 ms) during NSR, from 13 to 141 ms (mean of 66 ms) during VT, and from 10 to 72 ms (mean of 40 ms) during PVCs and were reproducible within each patient for each type of rhythm. In all patients, the difference in sequence and timing between the dual electrograms in NSR beats vs. ectopic beats allowed for the differentiation of normal and abnormal complexes. These differences in each patient ranged from 23 to 210 ms (mean of 81 ms) during VT and from 3 to 89 ms (mean of 44 ms) during PVCs. Fourteen of the 15 ectopic morphologies exhibited greater than 20 ms difference in timing compared to their corresponding NSR beats. Combined with the appropriate software, multiple ventricular leads may be used by antitachycardia devices to discriminate between normal and abnormal ventricular activity.
Inhomogeneity of Cellular Refractoriness in Human Atrium: Factor of Arrhythmia?
Authors: BOUTJDIR MOHAMED , LE HEUZEY JEAN YVES , LAVERGNE THOMAS , CHAUVAUD SYLVAIN , GUIZE LOUIS , CARPENTIER ALAIN , PERONNEAU PIERRE
Published: July 2006

Spatial inhomogeneity of refractory periods, as measured during clinical electrophysiological studies, is a known predisposing factor of arrhythmia. We studied elective refractory periods (ERP) and action potential duration (ADP90) on isolated human atrium. Twelve samples of right atrium obtained during cardiac surgery from patients with (n = 6) and without (n = 6) atrial fibrillation (AF) were studied by microelectrode technique. For each preparation, ERP were measured at basic cycle lengths (BCL) of 1,600, 1,200, 800, and 400 msec in five different cells located around (0.8 mm) the stimulating electrode. Dispersion of ERP was significantly greater in the AF group (96.7 ± 9 versus 70.9 ± 9 msec, p = 0.01). In the non‐AF group, we observed a positive linear correlation between (1) ERP and BCL (f = 0.86) (2) ADP90 and BCL (r̄= 0.93). On the contrary, in the AF group this correlation was absent between ERP and BCL (r̄= 0.28), poor between ADP90 and BCL (r̄= 0.62). These results suggest that nonhomogeneous recovery of excitability (dispersion and poor adaptation) may be an important factor of arrhythmia. This inhomogeneity is present at the cellular level as well as in the entire heart.
Antibodies to Human Sinus Node in Sick Sinus Syndrome
Authors: MAISCH BERNHARD , LOTZE ULRICH , SCHNEIDER JAKOB , KOCHSIEK KURT
Published: July 2006

The incidence of autoantibodies against human conducting tissue was studied in 45 pacemaker patients with sick sinus syndrome (SSS), in 17 patients with bradyarrhythmia, and jive patients with hypertensitive carotid sinus syndrome. Antibodies against the human sinus node were demonstrated in 29% of patients with SSS and in 24% of patients with bradyarrhythmia; a tenfold risk of SSS could be calculated in patients with this antibody as compared to age‐matched controls. At least two subtypes of anti‐sinus node antibodies were demonstrated: an antibody absorbable and another one not absorbable with ventricular myocardium. Patients with SSS and prior myocarditis of rheumatic fever have a threefold incidence of that antibody, demonstrating that anti‐conducting tissue antibodies are etiologic indicators for former inflammatory heart disease. These antibodies may play a role in the secondary immunopathogenesis of sick sinus syndrome. This hypothesis emerges as an interesting new pathogenetic concept.
Is Chronic Atrial Stimulation a Reliable Method for Single Chamber Pacing in Sick Sinus Syndrome?
Authors: MAST E. GIJS , VAN HEMEL NORBERT M. , BAKEMA LEX , DERKSEN BERT , DEFAUW JO A.M.
Published: July 2006

To evaluate the feasibility of chronic atrial pacing (AAI) in sick sinus syndrome (SSS), 22 patients (pts) with bradytachycardia syndrome (BTS) and 17 patients with only bradyarrhythmias (BA) were studied on the incidence of supraventricular tachycardias (SVT) and occurring AV block. A scoring system based on symptoms of SVT was developed (grade 0–5). All patients had proven normal AV conduction before PM implantation. In the BTS‐group, nine patients (41%) had symptomatic SVT at the end of follow‐up (mean 53 months), despite drug therapy. These patients had a high SVT score on entry (mean 3.2). High degree AV block occurred in three patients. Although in the BA‐group SVT arose in six patients (35%), there was only one symptomatic patient at the end of follow‐up (mean 36 months). In this group, only one patient developed high degree AV block. Atrial stimulation should be considered as a reliable therapy in patients with SSS and low SVT score before PM implantation when normal AV conduction is present.
The Effect of VVI Pacing and Resultant Atrioventricular Dyssynchrony on Segmental Volumes
Authors: SALO RODNEY W. , LINCOLN WILLIAM C. , KADERA JAMES D.
Published: July 2006

Left and right ventricular volumes were monitored simultaneously in four anesthetized dogs by intracardiac impedance ventriculography during normal sinus rhythm, spontaneous ventricular rhythm, and VVI and VDD pacing. Cardiac output was found to increase with VVI pacing rate but remained somewhat lower than normal sinus or VDD values. The dissynchronous atrial contraction was found to distort the volume waveforms but had little effect on right ventricular volumes. Left atrial contraction had the greatest impact on left ventricular filling at near normal AV delays. Cardiac output during VDD pacing was found to be a maximum at 170 msec and decreased in three of four dogs at 220 msec. Examination of volume waveforms during “filling” indicates that the right ventricle is dominated by passive filling while the left ventricle demonstrates a large active or “fast” filling phase.
Rate Stabilization by Right Ventricular Pacing in Patients with Atrial Fibrillation
Authors: WITTKAMPF F.H.M. , DE JONGSTE M.J.L.
Published: July 2006

A recent study of de Jongste has demonstrated the lengthening of short R‐R intervals in patients with atrial fibrillation by right ventricular pacing. We have further analyzed the data from this study and specifically looked at the effect of right ventricular pacing on the R‐R interval instability and heart rate. At the cost of only a slight increase in mean heart rate, a major reduction of the R‐R interval instability can be obtained by right ventricular pacing. Based on these findings, we have developed and evaluated an automatic pacing rate algorithm, which continuously varies the stimulation rate in order to stabilize the otherwise irregular rhythm in patients with atrial fibrillation.
Five‐Year Performance of the Medtronic 6971 Polyurethane Endocardial Electrode
Authors: PIRZADA FAROUK A. , SELTZER JEFFREY P. , BLAIR‐SALETIN DONNA , KILLIAN MAUREEN
Published: July 2006

There is a considerable debate over the long‐term performance of polyurethane electrodes. Observation to date has demonstrated surface cracking and some clinical failures in patients. Since 3978 we have implanted about 82 6971 Unipolar Medtronic electrodes in the ventricle. In 33 patients, lead integrity was assessed by chronic thresholds determined by decreasing pulse width and pulse amplitude. Sensing functions were assessed by electrocardiographic rhythm analysis. At a follow‐up between 7 and 67 months, chronic thresholds at 2.50 volts were 0.08 ± 0.04 milliseconds in 26 patients with Medtronic Pulse generators (Models 8423. 5985, and 7000). In two patients with similar units, no loss of capture was seen even at 0.05 milliseconds. Three patients, one with Cordis Unit (233F) showed loss of capture at 0.20 milliseconds at 2.00 MA, the other with a Pacesetter unit (255–6) showed loss of capture at 0.20 milliseconds, at 2.50 volts. One patient with Intermedies unit (283) lost capture at 0.07 milliseconds at 2.70 volts. Insulation breaks seen in two patients were demonstrated by pectoral stimulation and pacemaker oversensing. In addition, 24‐hour long‐term electrocardiographic monitoring was performed in 22 patients between 23 to 70 months. Appropriate pacemaker function was seen except in one patient who demonstrated oversensing. Interruption in insulation was demonstrated at the ligature site at exploration. Thus, in this series of patients who were paced in the ventricle by the 6971 Medtronic electrode, only two patients have demonstrated insulation failure. The incidence of insulation break in this polyurethane unipolar electrode is uncommon and occurs at further stress points.
Long‐Term Threshold Stability with Porous Tip Electrodes
Authors: GOULD LAWRENCE , PATEL CHANDRAKANT , BECKER WILLIAM
Published: July 2006

Experience with 163 unipolar tined porous endocardial electrodes is reported. One patient required repositioning of the electrode because of exit block. There were no other complications in the entire series of patients. All of the patients had low chronic stimulation thresholds. The mean pulse width 24 hours after implantation was 0.0534 ± 0.0128 ms. Seventy‐four patients were restudied six months after implantation. The mean pulse width threshold was then 0.07432 ± 0.0775 ms. Fifty‐four patients were evaluated one year after lead implantation. The mean pulse width threshold was then 0.0611 ± 0.0230 ms. The pulse generator was reprogrammed to a lower pulse width in all of the patients. This permitted a substantial prolongation of the pulse generator life. The cost effectiveness of the pulse generator was also greatly improved by pacing with reduced pulse widths. In an additional 16 patients, the voltage amplitude was reduced from 5.0 volts to 2.5 volts. This permitted an even greater increase in the pulse generator longevity.
Orthogonal Atrial Appendage Sensing
Authors: GOLDREYER BRUCE N. , AUBERT ANDRE E. , WYMAN MILFORD G. , DENYS BART G. , ECTOR HUGO
Published: July 2006

The characteristics of electrograms derived from a solid platinum‐iridium pacing catheter tip in contact with the right atrial appendage are compared to those derived from a Target‐tip electrode. Both are then compared to electrograms from two noncontacting orthogonal electrodes positioned more proximally within the atriai appendage. Wave form morphology and spectral energy distribution were determined for the three sets of electrograms. It is concluded that orthogonal electrodes placed within the atrial appendage may offer enhanced atrial sensing required by more sophisticated pacemakers.
Development of Glassy Carbon Electrode (Dead Sea Scroll) for Low Energy Cardiac Pacing
Authors: KATSUMOTO KEIICHIRO , NIIBORI TATSURU , TAKAMATSU TOSHIAKI , KAIBARA MAKOTO
Published: July 2006

We have developed a new type of glassy carbon electrode whose smooth surface with scattered craters reduces its polarization voltage. It has both excellent antithrombogenicity and slight tissue reaction. The energy threshold curve was the lowest when compared to the Siemens (411S, 412S) and the Solin (S‐100) electrodes.
Clinical Experience with 910 Carbon Tip Leads: Comparison with Polished Platinum Leads
Authors: MUGICA JACQUES , HENRY L. , ATTUEL PATRICK , LAZARUS B. , DUCONGE ROBERT
Published: July 2006

Since 1980, we have implanted 910 carbon tip leads from three different manufacturers. The pacing thresholds from these leads were compared to those of standard polished platinum electrode configurations. Our major findings are that while acute voltage thresholds are not significantly different, two of the three carbon tip leads that we used in the study have statistically lower chronic thresholds then polished platinum leads (p ≤ 0.01).
Clinical Results of Low Energy Unipolar or Bipolar Activated Carbon Tip Leads
Authors: PIOGER GUY , RIPART ALAIN
Published: July 2006

Biocompatibility of carbon makes it a good candidate for a pacing electrode. Moreover, activation of the electrode creates microporosity, which increases the surface area and reduces polarization losses. Chronic thresholds noninvasively measured on a large population of patients implanted with vitreous carbon electrodes of one manufacturer are significantly lower than those caused by polished platinum tip electrodes of the same manufacturer with similar electrode design.
Noninvasive Control of the Early Postimplantation Period
Authors: WINTER U.J. , DEUTSCH H.J. , HOEHER M. , BEHRENBECK D.W. , HOMBACH V. , HILGER H.H.
Published: July 2006

Modern programmable pacemakers often incorporate features that allow one to perform a series of diagnostic maneuvers to aid in postimplantation surveillance. These features often include noninvasive measurements of thresholds, lead impedance, and intracardiac electrogram recognition via telemetry circuits. Interindividual differences in these measurements are so great that one must utilize individual comparisons for longitudinal studies of reliability. While these devices allow “fine tuning” of individual units, they require major time‐consuming efforts and add to the total device costs.
Pacemaker Clinic Evaluations: Key to Early Identification of Surgical Problems
Authors: BYRD CHARLES L. , SCHWARTZ SUSAN J. , GONZALES MICHELE , BYRD CHARLES B. , SIVINA MANUEL , YAHR WILLIAM Z. , CIRALDO ROBERT J. , GREENBERG JACK J.
Published: July 2006

The pacemaker center evaluation was responsible for the timely reoperation of 341 pacemaker patients over the last three years. The most common indication for reoperation was battery end‐of‐service (46.3%). Battery testing and maintenance of accurate records for trend analysis ensures prompt generator replacement. Atrial and/or ventricular lead malfunction was the second largest indication (26.3%). Lead malfunction detected by bracketing capture and sensing thresholds included: dislodgement, penetration, exit block, fracture, insulation failure, and abnormal sensing. The third largest indication for reoperation was pacemaker pocket erosion and/or infection (15.5%). Examination of the pacemaker pocket site is an integral part of an evaluation. In conclusion, the three largest indications for reoperations can he best demonstrated in a pacemaker center where evaluations are personal and thorough, and accurate record keeping is maintained.
A Modified Actuarial Life‐Table Approach to the Analysis of Implantable Device Performance
Authors: KIM JOHN S. , BROSTE STEVEN K.
Published: July 2006

The actuarial life‐table method is often used by pacemaker manufacturers and the pacing research community to describe pacemaker and lead performance. Most life‐table methods allow for differing lengths of follow‐up but assume that all devices were followed from implant. Occasionally, however, devices come under follow‐up observation sometime after implant. This presentation describes an extension of the actuarial method to accommodate these kinds of data. The specific example to be considered involves follow‐up data collected by CardioCare, a commercial cardiac monitoring service, on the performance of Medtronic polyurethane leads. Patients subscribe to this service, generally at some time after actual device implant. Results showed that of 12, 112 patients with Models 4002, 6971, and 6972 leads who were followed by CardioCare, only 85 were followed from implant. If one were to exclude patients not followed since implant, more than 99% of the data would be lost. Using the modified approach with allowance for postimplant, entry resulted in an estimated three‐year cumulative survival probability for these leads of 95.7%. Treating all patients as if they were followed since implant, the probability would be 96.9%, an optimistic and biased estimate.
Ambulatory Pacemaker Surgery—Medical and Economical Advantages
Authors: ZEGELMAN M. , KREUZER J. , WAGNER R.
Published: July 2006

The first pacemaker implantation on an ambulatory basis was done in our hospital in 1980. Since then, approximately 1,000 pacemaker patients have been operated on as outpatients. In 1984, we performed 781 pacemaker operations including 624 ambulatory operations. 583 patients received ambulatory new implantations. 54 persons were supplied as outpatients with a dual chamber system, 31 with a rate responsive system. In order to avoid complications, we use a standardized procedure, especially because the operators change daily following a plan of rotation. Patients are observed for 3–4 h postoperatively before discharge. Complications due to ambulatory operating have not been noticed. The ambulatory implantation of single or dual chamber pacemakers has been proving true as a safe treatment in our clinic. The economical advantage is obvious. In 1984, 5,000 days of hospitalization could he avoided; complications attributable to hospital cross‐infection, immobilization, etc. could he reduced.
Strategies for the Management of Tachyarrhythmias
Authors: SOWTON E. , HOLT P.
Published: July 2006

Conversion of atrial fibrillation or flutter is electrical and, if drugs fail to prevent recurrence, low energy His bundle ablation with implantation of a rate responsive pacemaker is our routine. For re‐entry tachycardia, antitachycardia pacers are often the method of choice. We use bipolar automatically actuated systems exclusively, functioning either as burst overdrive or critically timed stimulation. His bundle, or accessory pathway ablation, is considered a later choice. Ventricular arrhythmias are initially terminated by Class I agents or cardioversion and then a trial of suppressive drugs used. If this foils, a combination of an antitachycardia pacemaker plus an automatic implantable defibrillator is implanted. Alternative options are ablation of the arrhythmogenic site, endomyocardial stripping, or on encircling ventriculotomy with cardiac transplantation as the final option considered.
Epidemiology of Ventricular Tachycardia/Ventricular Fibrillation and Sudden Cardiac Death
Authors: MYERBURG ROBERT J.
Published: July 2006

Despite the difficulties correlating pathological data with acute clinical events in the field of sudden cardiac death, information useful to both the clinician and the epidemiologist has developed. Sudden cardiac death may be defined broadly. These definitions have varied, but it is now generally recognized that sudden cardiac death should reflect a time span of less than one hour. The epidemiology of sudden cardiac death incorporates many factors, including age, heredity, gender, and race. Coronary risk factors and the history of prior coronary heart disease constitute additional points of importance. Finally, clinical characteristics of the cardiac arrest patient are variable. Improving outcome in prehospital cardiac arrest victims involves a multifactorial approach involving rescue personnel, resuscitation technology, and the participation of the public.
The Automatic Implantable Cardioverter Defibrillator: Results, Observations, and Comments
Authors: LUCERI RICHARD M. , THURER RICHARD J. , PALATIANOS GEORGE M. , FERNANDEZ PEDRO R. , EL‐SHALAKANY ASHRAF , CASTELLANOS AGUSTIN
Published: July 2006

The automatic implantable cardioverter‐defibrillator (AICD) is a device of proven efficacy in life‐threatening ventricular tachycardia and fibrillation. Initial experience with the AICD at the University of Miami consists of 21 patients with recurrent ventricular dysrhythmias for a total follow‐up of 3–35 months (mean 19). There were two deaths in the series, one nonarrhythmic and one arrhythmic, at the fifth and tenth postoperative months respectively. There were five complications requiring reoperation in three patients. Pacemakers were required in four patients with the AICD and resulted in interesting observations. Our data concur with previously published reports of improved survival in selected patients.
Use of Electrical Pacing and Automatic Cardioversion Defibrillation for Normal Cardiac Function Recovery
Authors: PEKARSKY VIKENTY , ASTRAKHANTSEV YURY , BELENKOV YURY , GIMRIKH EVALD , OFERKIN ALEXANDR , MASLOV MIKHAIL , POPOV SERGEY , PEKARSKAYA MARIANNA , MARKOV VALENTIN , VASILTSEV YAROSLAV
Published: July 2006

Antitachycardia pacing and low energy cardioversion terminated episodes of ventricular tachycardia and fibrillation and prevented extrasystoles in patients with acute myocardial infarction, coronary artery disease, and long QT syndrome. Low energy automatic defibrillation was used in 25 patients intraoperatively and during the early postoperative period. The Soviet prototype of an implantable cardioverter‐defibrillator [ICAR‐D] detects the arrhythmia automatically and delivers selectively an electrical impulse to the heart: 2.5–4 J for VT and 15–20 J for VF. In addition, the effectiveness of ICARD was studied in chronical experiments in 10 dogs with follow‐up of 4–6 months.
Automatic Implantable Cardioverter/ Defibrillator (AICD) and Antitachycardia Pacemaker (Tachylog): Combined use in Ventricular Tachyarrhythmias
Authors: LÜDERITZ BERNDT , GERCKENS ULRICH , MANZ MATTHIAS
Published: July 2006

Antitachycardia pacing in ventricular tachyarrhythmias (VT) is associated with potential acceleration of VT: frequency of VT and discomfort of the patient (pt) can limit treatment with the AICD. We therefore evaluated the combined use of antitachycardia pacing and AICD in 6 of 14 patients (age 50–70. mean 60 years) with AICD implantation because of VT, which could he terminated by temporary overdrive pacing. With the interactive mode of the Tachylog, termination of VT by the pacemaker as well as by the AICD was assessed after implantation. In the automatic mode, the Tachylog functioned as a bipolar VVI device with antitachycardia burst stimulation: 2–5 stimuli, interval 260–300 ms. 1–2 interventions. During follow‐up of 12±5 months, the Tachylog terminated VT reliably 20 to 327 times per patient. In three patients, burst stimulation accelerated VT, which was terminated then by the AICD discharge. Conclusion: Drug resistant ventricular tachyarrhythmias can be terminated by the Tachylog pacemaker avoiding patients' discomfort. In case of acceleration. ventricular tachyarrhythmias can be controlled by the automatic implantable cardioverter/defibrillator. A universal pacemaker should combine antitachycardia pacing with back‐up defibrillation mode.
Surgical Treatment of Supraventricular Tachycardia: A Five‐Year Experience
Authors: GUIRAUDON GERARD M. , KLEIN GEORGE J. , SHARMA ARJUN D. , YEE RAYMOND , McLELLAN DOUGLAS G.
Published: July 2006

Two hundred and eight patients underwent operative therapy of supraventricular tachycardia between June 1984 and June 1986. There were 196 patients with Wolff‐Parkinson‐White syndrome, one with AV nodal reentry, two with atrial flutter, one with ectopic atrial tachycardia, three with paroxysmal sinus tachycardia, and five with atrial fibrillation. Map guided or direct surgery was performed in all patients except the three with atrial fibrillation. Direct surgery was generally successful with failures including one patient with Wolff‐Parkinson‐White syndrome, one with atrial flutter, and the three patients with paroxysmal sinus tachycardia. There was no mortality. Major complications were uncommon and included three resternotomies for bleeding, one chylopericardium. Six patients required reoperation.
Catheter‐Mediated Electrical Ablation: The Relation Between Current and Pulse Width on Voltage Breakdown and Shock‐wave Generation
Authors: BARDY GUST H. , COLTORTI FERNANDO , STEWART ROBERT B. , GREENE H. LEON , IVEY TOM D.
Published: July 2006

Barotrauma from arc induced shock waves may result in dangerous sequelae during ablatian of arrhythmogenic foci. In this report, maximum pulse amplitude and pulse width determinations were made to assess, avoidance of shock‐wave generation using rectangular constant current pulses. Energy delivery appears to be optimal between 80–100 microseconds. If higher energies are required, multiple pulses will be needed to avoid barotrauma.
Rate‐Responsive Pacing: Biosensor Reliability and Physiological Sensitivity
Authors: ROSSI PAOLO
Published: July 2006

Various sensor systems that indicate the hypermetabolic state have been used to provide input signals for controlling rate responsive pacing systems. The sensitivity of an indicator may be related directly or indirectly to metabolic requirements. Metabolic, respiratory, and cardiac dynamics during exercise have been described. Direct measurement of oxygen consumption provides the best index of work rate and exercise capacity. In pacemaker‐dependent patients, heart rate is not an independent variable. During exercise, changes in pacing rate and hemodynamics do not show the specificity of a rate‐responsive system, but are the result of a combination of sensor response and electronic or signal processing. Following the general patterns of change in various measurable parameters during exercise with progressively increasing work rates, the hypermetabolic indicators have been categorized into five groups according to the accuracy of their relationship to oxygen consumption. The indicators that are used or proposed as sensors for the regulation of rate‐responsive systems are described. Sensor sensitivity, specificity, reliability, and physiologic sensitivity are defined and discussed with the single rate‐responsive system in clinical or experimental use.
Right Ventricular Blood Temperature Profiles for Rate Responsive Pacing
Authors: SELLERS T. DUNCAN , FEARNOT NEAL E. , SMITH HEIDI J. , DI LORENZO DANIEL M. , KNIGHT JAMES A. , JO SCHMALTZ MARY
Published: July 2006

To establish the efficacy of a temperature‐based pacemaker control algorithm, right ventricular temperature and heart rate were measured for 12–70 hours in eight patients (51 ± 17 years) and in one normal volunteer (28 years) during a variety of activities including exercise, rest, sleeping, eating, drinking, and bathing. A diurnal variation in heart rate and temperature was observed. Drinking caused transient temperature changes (less than one minute); during eating, increases of 0.07–0.36°C over 3–12 minutes were observed. An increase of 0.24°C over 8.5 minutes was observed in one patient during bathing. An abrupt drop in temperature was typically observed at the onset of exercise, followed by a steady temperature rise. During treadmill exercise, after a drop (0.13–0.48°C, Bruce n ‐ 4; 0A6–0.34°C, Naughton, n = 3) during the first 1–2 minutes, temperature rose steadily through the end of peak exercise (0.45–1.01°C, Bruce; 0.28–0.47°C, Naughton). A temperature dip was also observed when a patient was told exercise would start but the treadmill failed to turn on. The dip is probably secondary to changes in blood flow from the peripheral circulation to the central system at the onset of exercise. Repeated exercise separated by short rests caused progressive blunting of the initial dip. Right ventricular temperature changes in a predictable manner with daily activity, allowing a temperature algorithm to detect rest and exercise.
Pacing Techniques in the Prophylaxis of Junctional Reentry Tachycardia
Authors: DAVIES D. WYN , BUTROUS GHAZWAN S. , SPURRELL ROWORTH A.J. , CAMM A. JOHN
Published: July 2006

Atrial premature beats (APBs) which encounter sufficient AV delay may initiate junctional reentry tachycardia (JRT). This form of initiation may be prevented by rendering part of the reentry circuit refractory by artificial stimulation following an APB which would otherwise initiate JRT. Two such approaches have been suggested: preexcitation pacing, that is, ventricular stimulation with a short AV delay triggered by atrial depolarization; and preemptive pacing, which consists of early atrial stimulation coupled to the initiating APB. We compared these approaches and describe them as follows. Ten patients with JRT (six with atrioventricular reentry and four with AV nodal reentry) were studied. Against a background of regular atrial drive, the range of coupling intervals over which a stimulated APB initiated JHT (tachycardia initiation window) was determined (control). The tachycardia initiation window was also measured when a second atrial stimulus followed the initiating APB 20 ms after atrial recovery (preemptive pacing) or when a ventricular stimulus closely followed the initiating APB with an AV delay of 65 ms (preexcitation pacing). The tachycardia initiation window in response to an isolated APB was also assessed following regular AV pacing with a short (65 ms) AV delay (preconditioning pacing) and the effect of preexcitation pacing following the initiating APB was also assessed after a similar drive (combined preconditioning and preexcitation pacing). All protocols were performed at two basic drive cycle lengths. The results are arranged for the slow and fast drives, respectively, and were as follows: control initiating windows—49.5, 28.5 ms; preemptive pacing initiation windows—151, 38 ms; preexcitation pacing initiation windows—26, 23.5 ms; preconditioning pacing initiation windows—45.5, 35 ms; combined preconditioning and preexcitation pacing initiation windows—10.0, 2.5 ms. Whereas preemptive pacing tended to widen the tachycardia initiation windows (a proarrhythmic effect) the combination of preconditioning and preexcitation pacing considerably reduced the possibility of JRT initiation by an atrial premature beat.
Pacing and Sensing: How Can One Electrode Fulfill Both Requirements?
Authors: SINNAEVE ALEONS , WILLEMS ROGER , BAGKERS JOS , HOLOVOET GERMAIN , STROOBANDT ROLAND
Published: July 2006

Pacing and sensing are two different functions which can be accomplished by one and the same electrode. Optimal pacing requires a high tissue resistance in order to minimize the stimulation energy, making a small surface electrode highly desirable. For adequate sensing, however, the tissue resistance should be as low as possible which requires a larger electrode surface area. Decreasing the electrode surface area results in an increased polarization impedance. As this latter should he low for both pacing and sensing, an electrode with a large surface area should be used. How can these opposing needs be met by one electrode? The combination of a small geometrical surface and a large porous microstructure along with the choice of low polarizable materials meets both the requirements of pacing and sensing.
Automatic Implantable Cardioverter/ Defibrillator: Inadvertent Discharges During Permanent Pacemaker Magnet Tests
Authors: KIM SOO G. , FURMAN SEYMOUR , MATOS JEFFREY A. , WASPE LAWRENCE E. , BRODMAN RICHARD , FISHER JOHN D.
Published: July 2006

A patient with an automatic implantable cardioverter defibrillator (AICD)® received two inadvertent shacks when a magnet was placed over the pacer during a routine permanent pacer check. Analysis of the rhythm strip suggested that both patients’ QRS complexes (133 beats/minute) and asynchronous pacer artifacts (70 beats/minute) were counted by the AICD sensing system and exceeded the rate criteria of 153 beats/minute. This resulted in shocks from the AICD during sinus rhythm at 133 beats/minute. To avoid possible inadvertent shocks, an AICD should be deactivated while a magnet is placed over the pacemaker during a permanent pacer check.
Behavior of the Ventricular Triggering Period of DDD Pacemakers
Authors: BAROLD S. SERGE , BELOTT PETER H.
Published: July 2006

Fifty‐seven patients with implanted DDD pulse generators (23 Intermedics Cosmos and 34 Medtronic Symbios) were studied to characterize the behavior of the so‐called ventricular safety pace period or nonphysiologic AV delay (ventricular triggering period) in a variety of circumstances. The pulse generators were programmed to various combinations of upper rate, lower rate, and atrioventricular (AV) intervals. We then evaluated the response of the pulse generators to a variety of signals sensed by the ventricular channel during the ventricular triggering period (VTP). In the Cosmos DDD pulse generators, the VTP lengthened from its nominal value (100 ms) whenever the sum of the atrial escape (pacemaker VAJ interval and the nominal value of the VTP was shorter than the upper rate limit interval. Extension of the VTP reflected the necessary delay required to maintain constancy of the (ventricular) upper rate limit interval. In contrast, the Medtronic Symbios DDD pulse generators exhibited constancy of the VTP even when the sum of the atrial escape (pacemaker VA) interval and the duration of the nonprogrammable VTP (110 ms) was shorter than the upper rate limit interval. This response was observed only with a programmed lower rate of 90 ppm, upper rate of 100 ppm, and AV interval of 250 ms. Under these circumstances, in the presence of crosstalk or myopotentials sensed in the VTP, the Symbios DDD pulse generator violated its ventricular upper rate limit interval, but remained faithful to its separate (but equal) atrial upper rate limit interval by omitting the succeeding atrial stimulus. The behavior of the VTP of DDD pulse generators, particularly its relation to the upper rate response, must be known for the proper interpretation of pacemaker function.
Comparison of Myopotential Interference in Unipolar‐Bipolar Programmable DDD Pacemakers
Authors: GABRY MARK D. , BEHRENS MICHAEL , ANDREWS CAROLYN , WANLISS MARK , KLEMENTOWICZ PETER T. , FURMAN SEYMOUR
Published: July 2006

Myopotontial interference (MPI) can inhibit or trigger single and dual chamber unipolar pacemakers while bipolar pacemakers are resistant. Twenty units of two different models of dual chamber pacemaker, each capable of being programmed to single chamber or dual chamber and unipolar or bipolar function were tested to provoke myopotential interference. No patient had evidence of myopotential interference at any sensitivity setting in the bipolar configuration either in atrium or in ventricle. All patients (20/20) interfered with pacemaker function at the highest atrial or ventricular sensitivity settings in the unipolar configuration. T wave sensing occurred at the 0.25 mV sensitivity setting in four patients in pacemaker model 925, in both bipolar and unipolar configurations. Tiventy‐five percent of patients had myopotential interference at the unipolar atrial sensing threshold and did not allow a setting which would reject myopotential interfercnce while providing satisfactory atrial sensing. Twenty percent (2/10) had myopotential caused ventricular inhibition at the least sensitive ventricular channel setting in model 240G so that myopotential interference could not be avoided in that unit no matter how large the electrogram.