bluuebunny/crossref_metadata_2025 huggingface dataset:
Intravenous Adenosine Triphosphate Disodium: Its Efficacy and Electrophysiologic Effects on Patients with Paroxysmal Supraventricular Tachycardias
Authors: TAJIMA TSUNEMI , MURAMATSU TOSHIHIRO , KANAKA SHINICHIRO , YANAGISHITA YOSHIKI , IDE MASAO , DOHI YUTAKA
Published: July 2006

We studied the electrophysiologic effects of intravenous adenosine triphosphate disodium (ATP‐2Na) on 17 patients with paroxysmal supraventricular tachycardias (PSVTs). One patient had sinus node (SN) reentry, two had intraatrial (IA) reentry, 7 patients had AV nodal reentry and seven had atrioventricular reentrant tachycardias (AVRTs) with accessory pathways (APs). ATP‐2Na was injected during ventricular pacing in patients with AV nodal reentry and AVRTs with APs. A bolus injection of ATP‐2Na terminated all the PSVTs within 50 s except for one case of IA reentry (case 2). The sites of block at termination were the atrium in SN reentry and IA reentry, between A and H (AH) or between H and A (HA) in AV nodal reentry, and AH block in all the PSVTs with APs. The sites of action on the patients with AV nodal reentry were both the antegrade and retrograde pathways, while the modes of block were Mobitz type I and type II, respectively. ATP‐2Na during ventricular pacing in patients with AV nodal reentry produced Mobitz type II ventriculoatrial block (VAB) in four of seven cases. ATP‐2Na during ventricular pacing in patients with AVRTs with APs produced changes of atrial activation sequences in two patients, induction of PSVT in two patients, and Mobitz type II VA block in three patients. The former two phenomena suggested a retrograde AV nodal block and raised the possibility of a simple test for retrograde atrial fusion during ventricular pacing in patients with WPW syndrome. Chest discomfort of short duration was most commonly noted after ATP‐2Na administration.
Reduced Incidence of Myopotential Pacemaker Inhibition by Abdominal Generator Implantation
Authors: ROSENQVIST MÅRTEN , NORDLANDER ROLF , ANDERSSON MATS , EDHAG OLOF
Published: July 2006

Myopotential inhibition during permanent pacing with unipolar leads is a well‐recognized clinical problem. A study was undertaken to determine if implantation of the generator in abdominal subcutaneous tissue instead of the conventional pectoral implantation site would reduce the incidence of this inhibition. Forty patients with either an abdominal (group A. n = 20) or a pectoral (group P, n = 20) generator implantation site were subjected to a standardized protocol of muscle provocation and 24‐hour ECG. Pulse generators were programmed to the lowest sensitivity level (average, 2.0 mV). Pauses exceeding the stimulation interval were analyzed. During muscle provocation 85% of the patients in group P displayed inhibition, as against 5% in group A (p < 0.001]. During 24‐hour ECG, the corresponding values were 95% and 15%, respectively (p < 0.001). We concluded that abdominal generator implantation significantly reduces the incidence of myopotential inhibition in patients with unipolar pacemaker leads.
Amiodarone: Value of Programmed Electrical Stimulation and Holter Monitoring
Authors: FISHER JOHN D. , KIM SOO G. , WASPE LAWRENCE E. , JOHNSTON DEBRA R.
Published: July 2006

The value of programmed elecfrical stimulation (PES) and Holter monitoring in the assessment of amiodarone efficacy was reviewed. Many physicians have been disturbed by the persistent inducibility of arrhythmias in patients treated with amiodarone, who nevertheless do very well during the follow‐up period. Noninducibility was associated with a favorable prognosis among 366 VT patients. Eighty‐eight (24%)were noninducible on amiodarone, and 10% of these had recurrences, vs 39% in patients who remained inducible. Further, increased difficulty of induction with PES or induction of a slower or better tolerated VT may indicate a favorable outlook, and add to the value of PES. Few papers rigorously employed Holter monitoring in the assessment of amiodarone. In general, suppression of previously frequent arrhythmias implies excellent protection for patients with benign arrhythmias and moderate protection with malignant arrhythmias. By Holter assessment in 186 VT patients, arrhythmias were suppressed in 114 (61%), and 18% of these had recurrences vs 50% in patients whose arrhythmias were not suppressed. Studies attempting to correlate the results of PES and Holter monitoring in the same patients are lacking and may prove useful.
Atrial Lead Dislodgement with a DDD Pacemaker
Authors: GREENSPON ARNOLD J. , COX JAMES , GREENBERG RICHARD M.
Published: July 2006

A 48‐year‐old man with previous aortic valve surgery and aortic root repair had a DDD pacemaker inserted (using transvenous leads) for the treatment of complete heart block. An atrial J active fixation electrode was used. Four weeks following implantation the patient returned with an unusual electrocardiographic rhythm demonstrating two separate QRS morphologies. Both PA and lateral chesf x‐ray failed to demonstrate a change in lead position. The MARKER CHANNELTM of the DDD pulse generator confirmed that the alternating QRS morphologies were due to atrial lead dislodgement. Although uncommon, displacement of atrial active fixation leads may occur and lead to unusual electrocardiographic rhythms. Use of a MARKER CHANNELTM may aid in the diagnosis.
Ventricular Tachycardia: Historical Perspective
Authors: McGOVERN BRIAN , SCHOENFELD MARK H. , RUSKIN JEREMY N. , GARAN HASAN , YURCHAK PETER M.
Published: July 2006

Ventricular tachycardia is now diagnosed frequently in patients with organic heart disease. Although ventricular tachycardia was first demonstrated electrocardiographically 75 years ago, the natural history, fundamental mechanisms, and optimal management have remained elusive. Early observers commented on the rarity of occurrence and poor prognosis associated with this arrhythmia, yet with time, some patients with ventricular tachycardia were reported to survive for prolonged periods. Because of the sporadic nature of the arrhythmia and its variable prognosis, assessment of the efficacy of therapies has been difficult. A wide variety of treatments has been advocated with enthusiasm, but only a few have been consistently reported to be effective. Citation of historical data to claim benefit from new treatments should be viewed with caution.
Optimal Atrioventricular Delay in Physiological Pacing Determined by Doppler Echocardiography
Authors: FORFANG KOLBJØRN , OTTERSTAD JAN ERIK , IHLEN HALFDAN
Published: July 2006

Our study included eight patients with physiological pacemakers programmed to the VDD mode. The blood velocity in the aortic root was determined by Doppler echocardiography. Changes in the integral of maximum velocity reflect stroke volume changes. The Doppler probe was placed and held in the suprasternal position while programming the pacemakers from the VVI to all available AV delays in the VDD mode; the heart rates were nearly constant. Stroke volumes were highly dependent on changes of the AV delay; the optimum AV delay varied considerably from patient to patient. These changes were more pronounced in the patients with left ventricular strain due to aortic valve disease than in the patients with isolated conduction defects.
Atrial Capture and Dual Chamber Pacing
Authors: VAN MECHELEN ROB , VANDEKERCKHOVE YVES
Published: July 2006

During dual chamber pacing it is sometimes impossible to assess atrial capture even on the 12‐lead ECG. We developed a strategy to identify atrial capture when it is not possible to do so by ECG, and when the ECG shows no evidence of spontaneous or paced atrial activity.
Changes in QT Interval during Exercise Testing in Patients with VVI Pacemakers
Authors: ODA EIJI
Published: July 2006

. The changes in QT intervals were studied in nine patients with normal sinus node function who had VVI pacemakers. Though PP intervals uniformly shortened during exercise, the change in QaT* intervals during exercise was variable. The correlation between PP and QaT intervals varied from case to case. A good correlation was found in only two cases (r =+0.816 or +0.897); a fair correlation was found in four cases (r =+0.672, +0.615, +0.615, or −0.669) and in the remaining three, the correlation was poor (r =+0.494, +0.467 or−0.424). In patients who are candidates for VTI pacemaker implantation, changes in QaT intervals should be assessed during exercise stress testing to determine if the intervals shorten during exercise or not.

(QaT*: Interval from the pacing spike to the apex of T‐wave.)
Comparison of Ramp and Stepwise Incremental Pacing in Assessment of Antegrade and Retrograde Conduction
Authors: ZHANG XUMING , FISHER JOHN D. , KIM SOO G. , MATOS JEFFREY A. , WASPE LAWRENGE E. , JOHNSON CHARLES
Published: July 2006

. conduction. Conventional assessmenl of antegrade (AV) and retrograde (VA) conduction involves stepwise increments in pacing rates until block in conduction is observed. This study was designed to establish the comparative characteristics of ramp pacing, in which the rate is continuously and smoothly incremented until block occurs. Two hundred and ten patients participated in portions of this study. Stepwise pacing was performed in 10 beat/minute steps, with the rate held for at least 15 seconds at each step; if marked prolongation or variability in conduction was observed, the rate was held constant for up to 60 seconds to allow for accomodation. With ramp pacing, the rate was gradually increased at a steady 2–4 beats/minute/second. Whenever possible, both stepwise and ramp pacing were performed for assessment of both antegrade and retrograde conduction. All patients had conducted sinus rhythm as their baseline mechanism. Antegrade conduction was similar using incremental stepwise and ramp pacing. The AH interval at a cycle length (CL) of 500 ms, the maximum AH increment, the cycle length at AV block were all remarkably similar (p = NS). Assessment of retrograde conduction produced similar results, with insignificant differences between maximum conducted VA intervals, and cycle length at VA block using the two pacing techniques. Ramp pacing provides a useful and rapid alternative to conventional stepwise incremental pacing in the assessment of antegrade and retrograde conduction in patients using both normal and accessory pathways. Ramp pacing was better tolerated, and some correlations between antegrade and retrograde conduction were stronger with the ramp pacing technique.
Long‐Term Prognostic Significance and Electrophysiological Evolution of Intraventricular Conduction Disturbances Complicating Acute Myocardial Infarction
Authors: PAGNONI FRANCO , FINZI ANDREA , VALENTINI ROMANO , AMBROSINI FRANCESCO , LOTTO ANTONIO
Published: July 2006

Fifty‐nine patients with post‐infarctional, isolated intraventricular conduction disturbances (IVCD) who survived the acute stage of myocardial infarction were followed up after hospital discharge for a mean period of 11.4 ± 4.8 months. Fourteen patients (24%) had HV interval prolongation (>55 ms) during AMI (group A), and 45 patients had normal HV intervais (76%. group B). His bundle recordings were repeated during follow‐up in 48 survivors after a mean period of 7.2 ± 0.7 months. Infranodal conduction delay in the acute stage of infarction was correlated with a higher incidence of heart failure during AMI (78% of patients in group A vs 22% in group B, p < 0.01), and with higher rate of cardiac mortality during follow‐up (50% in group A vs 13% in group B. p < 0.01). Survivors of group A showed a higher functional NYHA class, a higher incidence of CHF, and a higher prevalence of complex ventricular arrhythmias at Holter monitoring. No statistically significant difference in late sudden death was evident between the two groups of patients, and the global incidence of late AV block was 2%. At repeat His bundle recording no significant change (>5 ms) in HV interval could be demonstrated in comparison to the acute phase recording, neither in patients with prolonged nor in patients with normal HV time. We conclude that HV prolongation in patients with isolated, post‐infarctional IVCD is correlated with a worse prognosis, both during acute infarction and during the follow‐up period, which presumably reflects wider anatomic damage in comporison to patients with normal HV time. The low incidence of late AV block and the electrophysiological demonstration of the stability of infranodal conduction several months after AMI indicate that these patients do not require permanent prophylactic pacing after acute myocardial infarction.
Transcutaneous Pacemaker Use in a Large Hospital
Authors: NOE ROBIN , COCKRELL WILLIAM , MOSES H. WESTON , DOVE JAMES T. , BATCHELDER JOHN E.
Published: July 2006

For an eight‐month period temporary transcutaneous and transvenous pacemaker use was analyzed in a 602‐bed hospital which had readily available fluoroscopy. Twenty‐four patients were treated with transcutaneous pacemaker; 23 of these were treated for asystole during cardiac arrest. The only patient not suffering cardiac arrest could not tolerate the transcutaneous pacemaker because of pain. Two of these 23 patients were treated early in the arrest with successful resuscitation. They became conscious and were able to tolerate the pacemaker well. Most of the other patients were treated late in the arrest with little chance of any therapy being successful. Only four of these 21 patients were treated within 15 minutes of the onset of cardiac arrest. During the same time span, 23 patients received transvenous temporary pacemakers. Only four of this group had suffered cardiac arrest before pacing.

We conclude that: (1) transcutaneous pacing can be successful but we did not find it useful when used late in a cardiac arrest; (2) transvenous pacing seemed the approach most often chosen for the non‐arrest situation.
Tricuspid Valve Perforation by a Permanent Pacing Lead in a Patient with Cardiac Amyloidosis: Case Report and Brief Literature Review
Authors: CHRISTIE JEFFREY L. , KEELAN MICHAEL H.
Published: July 2006

Tricuspid valve injury is a rare complication of transvenous pacemaker placement, We report such an injury in an elderly patient with cardiac amyloidosis. Because serious complications may result from such an injury, tricuspid valve perforation should be considered, along with the more common causes of new murmurs, in patients with pacemakers.
Repetitive Supraventricular Tachycardia: Clinical Manifestations and Response to Therapy with Amiodarone
Authors: HAINES DAVID E. , LERMAN BRUCE B. , DIMARCO JOHN P.
Published: July 2006

Repetitive supraventricular tachycardia is an uncommon arrhythmia which usually occurs in patients free of structural heart disease. It is characterized by incessant short salvos of supraventricular tachycardia separated by only one or two normal sinus beats. Therapy with conventional antiarrhythmic drugs is usually ineffective. This report describes three patients with repetitive supraventricular tachycardia in whom evidence for associated sinus node dysfunction was observed. Amiodarone therapy, with ventricular pacing in two patients, has provided effective control of this arrhythmia in all three patients.
Electrode Displacement from a Multipurpose Swan‐Ganz Catheter
Authors: HEISELMAN DARELL E. , MAXWELL JOHN S. , PETNO VINCENT
Published: July 2006

. A patient is described in whom a multipurpose pulmonary artery catheter had been placed. Upon removal of the catheter, it was noted that the electrodes had become detached from the lead. A new method is described for insertion and removal of the catheter which will prevent this complication.
Noninvasive Conversion of Atrial Flutter Using a Multiprogrammable DDD Pulse Generator
Authors: LUCERI RICHARD M. , CASTELLANOS AGUSTIN , THURER RICHARD J. , MYERBURG ROBERT J.
Published: July 2006

. A patient with sick sinus syndrome and resistant paroxysmal atrial flutter was treated with amiodarone and implanted with a Medtronic 7005 DDD pacemaker. Following discontinuation of amiodarone, an episode of sustained atrial flutter was converted to sinus rhythm by noninvasive rapid atrial pacing in the outpatient ciinic. This case illustrates one of the many capabilities for arrhythmic intervention using currently availabie implanted pacemakers.
Effects of AV Sequential Versus Asynchronous AV Pacing on Pulmonary Hemodynamics
Authors: DREIFUS LEONARD S. , MITAMURA HIDEO , RHAUDA ARMIN , VAIL SYDNEY , MICHELSON ERIC L. , BERKOVITS BAROUH V. , PETERSON DONALD D. , FIGUEROA WILLIAM F.
Published: July 2006

We studied the effects of various pacing modes on cardiac hemodynamics and pulmonary gas alterations in chronic heart blocked dogs. Changing the pacing mode from an atrioventricular interval of 100 ms (AV100) to a ventriculo‐atrial interval of 100 ms (VA100) caused a significant fall in left ventricular pressure (117.64 ± 11.91 to 95.60 ± 16.58 mmHg) and cardiac output from 2.18 ± 0.24 to 1.46 ± 0.20 L/min. Following the change in pacing mode from AV100 to VA 100, there was an increase in the alveolar‐arterial O2 gradient from 23.28 ± 6.97 to 28.74 ± 8.43 mmHg and a decrease in the arterial CO2 tension from 32.42 ± 3.22 to 29.42 ± 3.22 mmHg. There was also a decrease in arterial CO2 tension when the AV100 pacing mode was compared to asynchronous ventricular pacing (32.42 ± 3.22 versus 30.56 ± 2.82 mmHg). The minute volume of O2 also decreased when the pacing mode was changed from AV100 to asynchronous ventricular pacing (0.134 ± 0.01 versus 0.126 ± 0.01 L/min) and decreased further at VA100 to 0.114 ± 0.01 L/min. Other significant changes were also observed: the percent of expired CO2 decreased when the pacing mode was changed from AV100 to VA100 (3.68 ± 0.13 versus 3.37 ± 0.26%) or to asynchronous ventricular pacing (3.40 ± 0.31%). The end‐expiratory O2 increased and CO2 decreased when the pacing mode was changed from AV100 to VA100. The breath‐by‐breath correlation of end‐expiratory O2 and CO2 with left ventricular systolic pressure showed an almost immediate increase in O2 and reduction in CO2 concentration associated with decreasing systolic pressure. The decrease in pulmonary gas exchange appeared in part related to alterations in cardiac hemodynamics and particularly to the fall in cardiac output. It is speculated but not proven by these studies that alterations could be further explained by a fall in O2 consumption or reflex shunting of blood in vascular beds due to the fall in cardiac output. However, the additional deleterious effects of atrial contraction against a closed AV valve on pulmonary gas exchange and hemodynamics were also apparent. Notably, these studies could provide a physiologic basis for some symptoms associated with the pacemaker syndrome produced by the absence of AV synchrony.
Cardiac Syncope: A Case Exhibiting Dichotomy Between Clinical Impression and Electrophysiologic Evaluation
Authors: AONUMA KAZUTAKA , IESAKA YOSHITO , GOSSELIN ARTHUR J. , ROZANSKI JOHN J. , LISTER JOHN W.
Published: July 2006

This case report illustrates the value of electrophysiologic study in patients presenting with graphically unmonitored syncope and/or sudden cardiac death, and who have clinical markers of both bradycardia and ventricular tachycardia. In our patient, a wide QRS on the electrocardiogram and Holter monitor documented high grade ventricular ectopic activity. In this case, had therapy been solely guided by the clinical impression that the patient had ventricular tachycardia, the treatment would have resulted in increasing the risk of recurrence of syncope and/or sudden cardiac death.
Detection of Pathological Tachycardia by Analysis of Electrogram Morphology
Authors: DAVIES D. WYN , WAINWRIGHT RAY J. , TOOLEY MARK A. , LLOYD DAVID , NATHAN ANTHONY W. , SPURRELL ROWORTH A. J. , CAMM A. JOHN
Published: July 2006

Pacemaker recognition of pathological tachycardia relies on heart rate analysis. This can lead to misdiagnosis when sinus tachycardia exceeds the preset tachycardia response trigger rate. We have explored a method for automatic tachycardia diagnosis by analysis of bipolar endocardial electrogram morphology.

Electrograms were recorded from 11 patients (pts) during sinus rhythm and during a total of 20 abnormal rhythms: retrograde atrial depolarization from ventricular pacing in six patients; atrioventricular reentry tachycardia in five patients with intermittent left bundle branch block in one of those; AV nodal reentry tachycardia in five patients and ventricular tachycardia in three patients. Posture and respiration were varied during all rhythms except ventricular tachycardia. The electrograms were then digitized and converted to a form in which the amplitudes were proportional to the rates of change of the original electrogram (equivalent to a first time derivative); the derived signal was then analyzed by a new gradient pattern detection (GPD) program.

Analysis of the processed atrial signals by GPD resulted in automatic recognition of abnormal rhythms from sinus rhythm in all cases except for one patient's retrograde atrial depolarization. At the ventricular level, GPD successfully distinguished all abnormal rhythms from sinus rhythm including recognition of left bundle branch block and varying degrees of preexcitation. Respiratory and postural variation did not affect the recognition process.

We conclude that electrogram GPD has successfully and automatically detected a variety of arrhythmias which can be treated by implantable pulse generators and may, therefore, be a useful adjunct to heart rate analysis in future generations of such antitachycardia pacemakers.
Noninvasive Assessment of Ventriculo‐Atrial Conduction and Early Experience with the Tachycardia Termination Algorithm in Pacemaker‐Mediated Tachycardia
Authors: FONTAINE JOHN M. , MALONEY JAMES D. , CASTLE LON W. , MORANT VICTOR A.
Published: July 2006

Since Ihe advent of physiologic dual chamber pacing systems, pacemaker‐mediated tachycardia (PMT) has occurred and the need for invasive measurement of ventriculo‐atrial conduction (VAC) has arisen. The variability in VAC and the potential for PMT often make it necessary to assess for the presence or absence of VAC at different points in time. We noninvasively evaluated 20 pacemaker patients for the presence or absence of VAC. We compared ventriculo‐atrial conduction time (VACT) obtained with the atrial sense event marker with that obtained from Holter monitoring and invasive methods. The incidence of spontaneous (S) and induced (I) PMT and the efficacy of the tachycardia termination algorithm (TTA) was assessed. Fourteen of 20 had VAC with invasive or noninvasive methods. Twelve of 19 had PMT (63%); three were sustained (> 15 beats). We conclude that VACT assessed with the atrial sense event marker (ASEM) yielded a high correlation when compared to the Holter monitor data obtained utilizing our methodology. PMT is commonly a nonsustained (<15 beats) event, and the TTA is effective in sustained PMT. Myopotential sensing, atrial premature contractions and loss of atrial capture are common mechanisms in the initiation of PMT.
Unusual Sinus Node Response Curves in Two Cardiac Transplant Recipients
Authors: BEXTON RODNEY S. , NATHAN ANTHONY W. , CAMM A. JOHN
Published: July 2006

We describe unusual responses of the sinus node to programmed atrial stimulation in two asymptomatic cardiac transplant recipients. In one patient the sinoatrial conduction time, calculated using the revised method of Strauss, is extremely short (5 ms), and in the other it is extremely long (460 ms). The various mechanisms that might be involved in these atypical responses to atrial extrastimulation are discussed. These include sinus node suppression, shift of pacemaker, direct stimulation of are the sinus node and shortening of the sinus node action potential duration.
Limitations to Activation of the Antitachycardia Burst Pacing Function of the Symbios 7008 Pacemaker in the Universal (DDD) Mode
Authors: ROTHSCHILD J.M. , WYSE D.G.
Published: July 2006

The Symbios 7008 anfitachycardia pacemaker was implanted in five patients for control of supraventricular tachycardia. Shortly after Implantation in the first two patients, it was noted that the burst pacing sequence was not automatically activated by tachycardia when the pacemaker was in the DDD mode. Data from these two and the subsequent three patients were evaluated to explain this observation. The problem was primarily related to the operation of the device during the postventricular atrial refractory period. In all patients, the atrial elecfrogram encroached upon the programmed postventricular atrial refractory period because VA conduction during SVT was less than the lowest programmable interval (155 ms). Atrial events occurring during this interval will not trigger the tachycardia termination sequence. In all five patients, the size of the atrial electrogram decreased substantially (48 ± 10%; mean ± SD) during supravenfricular tachycardia compared to sinus rhythm. In at least two of the five patients, decreased atrial size during supraventricular tachycardia may also have resulted in intermittent failure of atrial sensing during tachycardia, even at the most sensitive setting (0.6 mV). The latter may remain a problem even if the technical fault in SVT detection in the DDD mode were corrected. Two related problems were noted in the DDD mode: (1) ventricular events during rapid SVT do not reset the low rate interval, resulting in random low rate pacing; and, (2) automatic prolongation of atrial refractory period by two successive ventricular events without an intervening atrial sensed event compounds problems of atrial sensing. All of these problems were easily circumvented in all patients by noninvasive reprogramming to the DVI mode in which supraventricular tachycardia detection is based on ventricular sensing. These findings have implications for the future design of such devices.
Clinical Usefulness of Chest Wall Stimulation in Patients with Automatic Tachycardia Terminating Pacemakers
Authors: BAROLD S. SERGE , FALKOFF MICHAEL D. , ONG LING S. , HEINLE ROBERT A.
Published: July 2006

Chest wall stimulation may be used diagnoslically and therapeutically in the follow‐up of patients with automatic tachycardia‐terminating pulse generators. In this report, we present our experience with chest wall stimulation in the follow‐up of five patients with implanted Intermedics CyberTach 60 automatic tachycardia‐terminating pacemakers (three for supraventricular tachycardia and two for ventricular tachycardia). Chest wall stimulation delivered at a rate faster than the rate detection criterion of the pulse generator often precipitates reentry tachycardia, making it possible to perform a noninvasive electrophysiologic study. In addition, chest wall stimulation may be invaluable in the termination of reentry tachycardia which is unsensed by an implanted pulse generator either because the rate is too slow, or below the rate detection criterion, or because the intracardiac signal does not attain the sensitivity of the pulse generator.
Improved Transesophageal Recording and Stimulation Utilizing a New Quadripolar Lead Configuration
Authors: KERR CHARLES R. , CHUNG DAVID C. , COOPER JOCELYN
Published: July 2006

Transesophageal pacing and recording are valuable techniques in the diagnosis and treatment of patients with arrhythmias. Bipolar pacing with bipolar catheters has been effective, but recording from the same electrodes is not possible during and immediately following pacing. We utilized a fine no. 4 French quadripolar catheter in 21 subjects to stimulate the atrium and record atrial electrical activity simultaneously. Pacing characteristics were equivalent to previously used bipolar catheters and recording was markedly enhanced. Bipolar atrial electrograms could be recorded either during pacing or at the first atrial depolarization following pacing in all patients. Thus, this quadripolar pacing lead improves the diagnostic value of studies involving transesophageal atrial pacing and recording.
Optimum AV Interval in Dual Chamber Pacemakers
Authors: HASKELL RICHARD J. , FRENCH WILLIAM J.
Published: July 2006

Approximately 50–70% of permanent implanted pacemakers are dual chamber pacemakers. However, little is known concerning adjustment of the atrioventricular (AV) interval to maximize cardiac output. Ten consecutive patients with complete heart block and dual chamber pacemakers were paced at heart rates of 80, 100, and 118 beats/ minute and at five AV intervals with simultaneous measurments of cardiac output using pulsed Doppler. Maximum cardiac output occurred at AV intervals of 150 and 200 ms at rates of 80 and 100 beats/minute, and at 150 ms at a rate of 118 beats/minute (p < .05). An increase in the AV interval to 250 ms resulted in a decrease in cardiac output at all heart rates (p < .01). We recommend the noninvasive measurement of cardiac output, if available, for determining the optimum AV interval in an individual patient; otherwise, an AV interval of 150 or 200 ms will provide the highest cardiac output in most patients.
Combination of Antitachycardia Pacemaker and Automatic Implantable Cardioverter/Defibrillator for Ventricular Tachycardia
Authors: MANZ MATTHIAS , GERCKENS ULRICH , FUNKE HERMANN DIETRICH , KIRCHHOFF PAUL GERHARD , LÜDERITZ BERNDT
Published: July 2006

Antitachycardia pacing for ventricular tachycardia (VT) is associated with the possibility of fibrillating the heart; on the other hand, (he frequency of VT and patient discomfort can limit treatment with the automatic implantable cardioverter/defibrillator (AICD). To contribute to the further deveJopment of a universal pacemaker, we evaluated the combined use of the anti‐tachycardia pacemaker (“tachylog”) and the AICD in five patients with recurrent VT. In the automatic mode, the “tachylog” worked as a bipolar VVI pacemaker. For antitachycardia pacing, a burst of rapid ventricular pacing was delivered at about 80% of the cycle length. During a follow‐up period of 5 ± 2 months (range, 3 to 8) two to 291 successful interventions of antitachycardia pacing were counted from diagnostic data which had been collected by the pulse generator during the course of treatment. When the antitachycardia pacemaker failed to terminate VT, the AICD was activated. In the individual case, between 0 and 41 discharges of the AICD were delivered. The high pulse energy of the AICD did not damage I/in antitachycardia pacemaker; no interference of the two devices was observed. Future antitachycardia systems should be more flexible with regard to detection and termination modes, combining antitachycardia pacing with back‐up defibrillation.
A Case of Ventricular Undersensing in the DDI Mode: Cause and Correction
Authors: BERTUSO JOHN , KAPOOR AMAR S. , SCHAFER JOHN
Published: July 2006

A case is presented that demonstrates a confusing problem of ventricular undersensing in the DDI pacing mode, Electrocardiographic monitoring of the patient after pacemaker implantation revealed intermittent ventricular channel outputs which appeared to be inappropriate. These occurred a period of time after the intrinsic R wave, equal to the programmed AV interval. This problem was caused by ventricular lead undersensing, which resulted when the patient's intrinsic rate was such that the intrinsic ventricular complex occurred during the ventricular blanking period. The problem was corrected by reprogramming the blanking period.
Noise Reversion of a Dual Chamber Pacemaker without Noise
Authors: FRÖHLIG GERD , DYCKMANS JAN , DOENECKE PETER , SEN SEMI , BETTE LUDWIG
Published: July 2006

Three patients are reported whose DDD pacemakers reverted to the asynchronous mode in the absence of skeletal muscle or electromagnetic (EMI) interference. In all three cases, the basic cardiac rhythm was atrial fibrillation with fast ventricular response due to intrinsic AV conduction. Noise reversion was triggered by the patients' own ventricular activity at cycle lengths shorter than the ventricular refractory period of the pulse generator. In one patient, asynchronous AV sequential pacing during atrial fibrillation was noted shortly after resuscitation from ventricular fibrillation; however, the initiation of the malignant ventricular arrhythmia by the pacemaker remains unproven. The mechanism of noise reversion by rapid cardiac activity and possible solutions to the problem by adequate pacemaker design are discussed.
Ventricular Pacing as the Preferable Mode for Long‐Term Pacing in Patients with Carotid Sinus Syncope of the Cardioinhibitory Type
Authors: STRYJER DOV , FRIEDENSOHN AHARON , SCHLESINGER ZVI
Published: July 2006

This study was designed to determine the efficacy of long‐term VVI pacing in patients having the isolated cardioinhibitory type of carotid sinus syncope. The study included 20 patients suffering from repeated syncopal attacks; all were proven by electrophysiological studies to have isolated forms of cardioinhibitory type carotid sinus syncope. Long‐term pacing by the VVI mode was carried out in all patients by programming the pacemaker rate weJJ below the patient's sinus rate. The follow‐up period after pacemaker implantation, which ranged from 2 to 54 months (average, 20 months), revealed that none of the patients had any recurrence of syncopal attack. Repeated Holter monitoring showed that ten had permanent sinus rhythm without any artificial pacing activity, while in the other ten, pacemaker activity was recorded–predominant in two patients and rare in the other eight. During Holter monitoring, attacks of weakness were reported by four patients; however, they were not related to pacemaker activity. This report indicates the importance of electrophysiological studies in patients suffering from carotid sinus syncope. These studies make possible the diagnosis of the isolated form of cardioinhibitory type syncope for which VVI pacing offers complete relief of symptomatology, thus rendering AV sequential pacing superfluous.
Atrial Synchronous Ventricular Inhibited (VDD) Pacemaker‐Mediated Arrhythmia Due to Atrial Undersensing and Atrial Lead Oversensing of Far‐Field Ventricular Afterpotentials or Paced Beats; Crosstalk
Authors: JOHNSON CHARLES D.
Published: July 2006

A patient is described with an epicardial atrial or P wave synchronous ventricular inhibited VDD pacemaker which had atrial sensing malfunction manifesting as failure of atrial sensing, and atrial sensing of far‐field ventricular polarization voltage afterpotentials or ventricular electrograms which mediated pacemaker allorhythms and tachycardias associated with dislocation of the atrial electrode near the right ventricle.
Antibiotic Prophylaxis in Pacemaker Surgery: A Prospective Double Blind Trial with Systemic Administration of Antibiotic Versus Placebo at Implantation of Cardiac Pacemakers
Authors: BLUHM GÖSTA , NORDLANDER ROLF , RANSJÖ ULRIKA
Published: July 2006

In a double blind clinical trial, 106 consecutive patients scheduled for pacemaker implantation were randomly assigned either to a systemic prophylaxis group (SPG) (to be given flucloxacillin) or to a control group who would be given a placebo (CPG). The SPG group received 2 g IV flucloxacillin 1 hour before the operation, then 1 g perorally every 8 hours for the next jive days. In the CPG group, placebo infusions and tablets were given at the same schedule. There were a total of 106 patients (SPG 52, CPG 54) who met the criteria of the study. Of these, 102 patients (SPG 50, CPG 52) completed a follow‐up of 7–35 months. Infection of the pacemaker system was not diagnosed in any patient in either group. Tissue fluid was drawn 24 hours postoperatively from the pacemaker pocket for culture and for determination of pocket antibiotic concentration. The mean flucloxacillin concentration of pocket fluid from 23 patients in the SPG was 7.5 μg/ml. The bacteriological cultures were positive in 9/32 patients in the SPG group and in 10/34 patients in the CPG group. This study suggests that antibiotic prophylaxis need not routinely be given at implantation of permanent pacemaker systems.
Supriority of Multiprogrammable to Nonprogrammable VVI Pacing: A Comparative Study with Special Reference to Management of Pacing System Malfunctions
Authors: PLESS PETER , SIMONSEN ERIK , ARNSBO PER , FABRICIUS JØRGEN
Published: July 2006

Analysis of pacing system malfunctions was performed in 374 patients at initial implantation or at pulse generator and lead replacement during a period of 55 months. A total of 150 nonprogrammable pacemakers were implanted in 148 patients, while 236 multiprogrammable pacemakers were implanted in 226 patients. The purpose of the analysis was to investigate the occurrence and management of malfunction unrelated to pacemaker/lead failure or lead dislodgement. The nonprogrammable group was followed for 3–53 months (median, 36). Malfunction occurred in 18 patients (12.0%); muscle stimulation in 14; exit block in three; sensing problem in one. Surgical correction was necessary in 14 of 18 cases. The multiprogrammable group was followed for 3–52 months (median, 12). Malfunction occurred in 30 cases (12.7%): muscle stimulation in 22; threshold increase in seven; sensing problem in one: Only seven of these patients required surgical correction as 23 cases were successfully managed by reprogramming alone. Malfunctions occurred during a period of several days to 36 months (median, 2.3 months). The difference in rate of secondary surgical intervention was significant (p < 0.01). Measurements during reoperation in the nonprogrammable group showed that at least 40% of late malfunctions would have been correctable by reprogramming alone. Thus, multiprogrammability is of significant value for noninvasive correction of malfunctions unrelated to pacemaker and lead failures, predominantly muscle stimulation and threshold elevation.
The Characterization of Human Transmyocardial Impedance during Implantation of the Automatic Internal Cardioverter Defibrillator
Authors: LAWRENCE JOHN H. , BRIN KENNETH P. , HALPERIN HENRY R. , PLATIA EDWARD V. , TSITLIK JOSHUA E. , LEVINE JOSEPH H. , GUARNIERI THOMAS
Published: July 2006

We set out to determine in a prospective fashion the characteristics of energy delivery related to defibrillation in a population of patients receiving the AICD. Specifically, we examined the characteristics of the delivered current, transmyocardial voltage, and transmyocardial impedance. Secondly, we determined the relationship between the energy delivered, the impedance encountered and the defibrillation threshold. Since the AICD will deliver a succession of shocks if the initial shock does not cardiovert, the effects of consecutive shocks at different energy levels on the transmyocardial impedance were also assessed.
Detection of Insulation Failure by Gradual Reduction in Noninvasively Measured Electrogram Amplitudes
Authors: VAN BEEK GERARD J. , DEN DULK KAREL , LINDEMANS FRED W. , WELLENS HEIN J.J.
Published: July 2006

Insulation failure of pacemaker leads may give rise to functional defects such as under‐ or oversensing, loss of capture or muscle stimulation. An increased incidence of such failures has been reported for the bipolar polyurethane‐insulated Medtronic model 6972 pacing lead. It is therefore important to identify techniques that will detect such insulation defects early. A case report is presented in which diminishing electrogram amplitude at follow‐up predicted lead failure several months before becoming clinically manifest. This finding suggests that routine measurement of such an electrogram may be a useful tool in predicting impending lead malfunction.
Electrophysiologic Studies of Patients with Hypertrophic Cardiomyopathy Presenting with Syncope of Undetermined Etiology*
Authors: SCHIAVONE WILLIAM A. , MALONEY JAMES D. , LEVER HARRY M. , CASTLE LON W. , STERBA RICHARD , MORANT VICTOR
Published: July 2006

Patients with hypertrophic cardiomyopathy (HC) have a high risk of sudden death. The best clinical predictors of sudden death from HC are young age, strong family history of sudden death, ventricular tachycardia (VT), and progression of symptoms such as syncope. We performed 24‐hour Holter monitoring and electrophysiologic studies (EPS) on 26 patients with HC, some with the obstructive form of the disease and some with syncope, in order to predict their vulnerabilily to syncope and to potentially malignant arrhythmias.

Holter monitoring demonstrated supraventricular tachycardia [SVT] in 9/26 patients whereas atrial programmed electrical stimulation induced SVT in 17/26 patients. Of the 17 patients, nine had symptomatic hypotension with SVT while lying supine. Holter monitoring demonstrated nonsustained VT in 7/26 patients whereas ventricular programmed electrical stimulation induced VT or ventricular fibrillation (VF) in 6/26 patients. The patient who had the longest run of nonsustained VT on Holter had VF induced by ventricular programmed electrical stimulation. He was cardioverted to normal sinus rhythm with no untoward effects.

We found that atrial programmed electrical stimulation induced SVT with hypotension best predicted a history of syncope in these patients. Although one patient required direct current cardioversion, EPS was conducted safely in all patients. Further long‐term studies are needed to demonstrate the value of clinical decisions based upon EPS in patients with HC.
Reproducibility of Electrophysiologic Parameters of Extrinsic Sinus Node Function in Patients with and without Sick Sinus Syndrome
Authors: DE MARNEFFE M. , JACOBS P. , ENGLERT M.
Published: July 2006

In a group of 50 patients we investigated the daily reproducibility of the resting heart rate (RHR), the maximal corrected sinus node recovery time (CSNRTM), the pacing rate at which the CSNRTM occurred (OP), and the sinoatrinl conduction time (SACT) during basal slate. The study population was divided into two groups according to the presence or absence (as evidenced during the initial electrophysiologic study) of sinus node disease: group I included 35 patients with normal sinus node function, and group II included 15 patients with sick sinus syndrome. The electrophysiologic study was repeated approximately al the same hour and under similar conditions after an interval of at least two days (mean: 3.2 days for group I and 4.7 days for group II). The results showed good reproducibility with the exception of RHR in group I which slightly but significantly decreased in the second electrophysiohgic study. The daily variations of the sinus node parameters appeared to be of similar levels in the two groups except for the CSNRTM; this parameter showed wide variations in single values in both groups, more marked in group II than in group I. Furthermore, if the CSNRTM and/or SACT were normal, it was likely that they would remain normal whatever the electrophysiologic status of the patient. Inversely, the change of status from abnormal to normal CSNRTM or SACT was not uncommon in patients with electrophysiologic signs of sinus node disease.
Antitachycardia Pacing: A Comparison of Burst Overdrive, Self‐Searching and Adaptive Table Scanning Programs
Authors: HOLT P. , CRICK J.C.P. , SOWTON E.
Published: July 2006

HOLT, P.

Eight patients with the Siemens Elema “Tachylog” genera for implanted for management of paroxysmal reentrant tachycardia were studied to assess the safety and efficiency of three antitachycardia programs. The programs investigated were burst overdrive, self‐searching, and adaptive table scanning. There were five males and three females aged 19–62 years. Seven had Wolff‐Parkinson‐White syndrome, and one had dual atrioventricular nodal pathways. Four had right atrial electrodes and four had right ventricular electrodes. Patients were studied lying, standing, and exercising in all three modes, and the appropriate long‐term programs were chosen. The generator remained in a program for 1 month, if was interrogated and the memory was read, and then it was reprogrammed to a different antitachycardia mode. Burst overdrive was unsuitable for long‐term use in four patients, producing atrial fibrillation in one and ventricular arrhythmias in three. In this group, self‐searching and adaptive table scanning were safe and equally effective (mean number of attempts/tachycardia 6.97 and 6.3, respectively). In the four patients in whom all three programs could be used, burst overdrive proved to be most efficient, the mean number of attempts/tachycardia were 2.4 (cf 9.6 and 9.0 for self‐searching and adaptive table scanning). Thus, burst overdrive was only suitable for long‐term use in 50% of our patients, but when safe it was more efficient than the other two programs, especially in those with narrow termination windows on exercise.
Paradoxical Induction of Endless Loop Tachycardia by Magnet Application Over a DDD Pacemaker
Authors: BAROLD S. SERGE , FALKOFF MICHAEL D. , ONG LING S. , HEINLE ROBERT A.
Published: July 2006

It is well known that removal of a testing magnet from a DDD pulse generator may cause endless loop tachycardia in patients with retrograde ventriculoatrial conduction; application of the magnet then terminates the tachycardia. We have observed the opposite response to the magnet and in this report we describe the paradoxical induction of endless loop tachycardia by magnet application over a DDD pulse generator and its persistence despite repeated removal and reapplication of the magnet. This unusual behavior occurred only in the “magnet off” function and is due to magnet‐induced signals sensed by the atrial channel circuitry.
Inappropriate Ventricular Blanking in a DDI Pacemaker
Authors: ERLEBACHER JAY A. , STELZER PAUL
Published: July 2006

The DDI mode is a new pacing mode with potential advantages over DVI pacing. We describe anomalous post R wave ventricular pacing due to the presence of inappropriate ventricular blanking periods in a pacemaker programmed to the DDI mode. Although no adverse consequences were seen in our patients, potentially dangerous R‐on‐T pacing could occur, particularly if long atrioventricular delays are programmed. A method for eliminating this pacing anomaly is described. Patients programmed to the DDI mode with the pacemaker model described should be evaluated for post R wave ventricular pacing and corrective measures should be taken.
Polymorphous Ventricular Tachycardia and Atrioventricular Block
Authors: STRASBERG BORIS , KUSNIEC JAIRO , ERDMAN SHIMSHON , LEWIN RUBEN F. , ARDITTI ALEXANDER , SCLAROVSKY SAMUEL , AGMON JACOB
Published: July 2006

Nine patients are presented who had polymorphous ventricular tachycardia (PMVT) occurring during alrioventricular (AV) block. There were five men and four women with a mean age of 80 ± 9 years. Five patients had organic heart disease and the remaining four had primary conduction disease (bundle branch block). AV block was complete in four patients (2:1 in three, and paroxysmal in two). The mean ventricular cycle length(of the AV block rhythm) was 1567 ± 203 ms. The mean QT interval was 0.64 ± 0.09 s and the mean QTc was 0.51 ± 0.06 s. When compared to a similar control group with AV block but without PMVT, the ventricular cycle length was similar but the QT and QTc were significantly longer. PMVT was usually of short duration (eight beats to 12 s) and in seven of these nine patients, frequent premature ventricular beats (PVBs) were recorded at various times from the occurrence of PMVT. This is in contrast to the control patients in whom PVBs were detected in one patient only. In conclusion, patients with AV block who develop PMVT usually have longer QT intervals and have detectable PVBs on routine ECGs, unlike similar patients with AV block but without PMVT. In a patient with AV block, a QT interval above 0.60 s and PVBs an the ECG seem to indicate an increased risk for the development of PMVT.
Polyurethane Sheath Disintegration Causing Impaction of Pacer Lead and Shock during Attempted Removal
Authors: HUBBELL DAVID S. , TYLER GILMAN R. , ZOBLE ROBERT G.
Published: July 2006

Steady traction to remove a lead whose polyurethane sheath had disintegrated caused displacement of the heart and caused hypotension; the bared lead uncoiled and impacted in the wall of the subclavian vein. The tension on the intrathoracic lead was relieved via immediate anterior thoracotomy and compartmentalization of the superior vena cava.