bluuebunny/crossref_metadata_2025 huggingface dataset:
Symptomatic Atrial Pacemaker Lead Thrombosis: Detection by Echocardiography and Successful Surgical Treatment
Authors: WIERZBOWSKA K. , KRZEMIŃSKA‐PAKUŁA M. , MARSZAL‐MARCINIAK M. , DROŻDŻ J. , ZASŁONKA J. , KASPRZAK J. D.
Published: July 2003

WIERZBOWSKA, K., et al.: Symptomatic Atrial Pacemaker Lead Thrombosis: Detection by Echocardiography and Successful Surgical Treatment. Formation of thrombi on a permanent pacemaker lead is a rare complication of pacing. However, because of its serious outcome it should be suspected in a patient who reveals right‐sided heart failure, dyspnea, or syncope. An early decision to perform an echocardiographic examination, followed by surgical or thrombolytic treatment can solve this clinical problem. In a 69‐year‐old woman with increasing signs of congestive heart failure, echocardiography revealed a mobile mass in the right atrium attached to the pacemaker lead. Because of threatened symptoms and large dimensions of the mass, urgent surgical removal of the endocardial lead was successfully performed.
The Hot Can: ICD Failure Presenting as Severe Shoulder Pain
Authors: JOGLAR JOSE A. , KOWAL ROBERT C. , BROWN TIMOTHY , VAN HORN BRENDA , PAGE RICHARD L.
Published: July 2003

JOGLAR, J.A., et al.: The Hot Can: ICD Failure Presenting as Severe Shoulder Pain. We describe a patient whose presentation of ICD generator failure was excruciating shoulder pain lasting 3 hours. This painful episode prompted evaluation and subsequent generator replacement. Destructive analysis of the explanted device revealed a short circuit of three battery filter capacitors, which resulted in the battery “dumping” its full energy very rapidly, since the impedance across the battery terminal was < 1 ohm. The duration of the painful episode was equal to the estimated ICD battery life under this low impedance condition.
Clinical Utility of Intraatrial Pacemaker Stored Electrograms to Diagnose Atrial Fibrillation and Flutter
Authors: POLLAK WAYNE M. , SIMMONS JEFFERY D. , INTERIAN ALBERTO , ATAPATTU SURESH A. , CASTELLANOS AGUSTIN , MYERBURG ROBERT J. , MITRANI RAUL D.
Published: July 2003

POLLAK, W.M., et al.: Clinical Utility of Intraatrial Pacemaker Stored Electrograms to Diagnose Atrial Fibrillation and Flutter. The purpose of this study was to determine if intraatrial electrograms (EGMs) are required to diagnose specific types of atrial tachyarrhythmias detected by pacemaker diagnostics. DDD pacemakers in 56 patients were programmed to store episodes of atrial tachyarrhythmias. Some episodes had a stored atrial EGM snapshot of the atrial tachyarrhythmia. The EGMs were analyzed to confirm whether the stored episodes were true atrial tachyarrhythmias or other pacemaker‐sensed events. EGM confirmation of atrial tachyarrhythmias correlated with increasing duration and rate of episodes. In particular, using EGMs, 8 (18%) of 44 episodes < 10 seconds in duration confirmed atrial tachyarrhythmias compared to 16 (89%) of 18 episodes > 5 minutes in duration (P < 0.001). Only 10 (18%) of 56 detected atrial arrhythmia episodes at rates < 250 complexes per minute were confirmed by the atrial EGM as true arrhythmias compared to 33 (57%) of 58 detected episodes at rates > 250/min (P < 0.001) Twenty‐nine (91%) of 32 EGM confirmed episodes of atrial fibrillation/flutter had an atrial rate > 250 complexes per minute and were a minimum of 10 seconds in duration. Fifteen (88%) of 17 episodes meeting the combined stored data criteria of > 250 complexes per minute and duration > 5 minutes were confirmed as atrial fibrillation or flutter by stored EGMs. Atrial EGMs identified that 71 (62%) of 114 stored high atrial rate (HAR) episodes were events other than true atrial tachyarrhythmias. Pacemaker diagnostic data with intraatrial EGMs can diagnose specific atrial tachyarrhythmias and identify other pacemaker‐sensed events. Stored episodes > 250 complexes per minute and > 5 minutes in duration had a high correlation with atrial fibrillation and flutter.
Single Catheter Determination of Local Electrogram Prematurity Using Simultaneous Unipolar and Bipolar Recordings to Replace the Surface ECG as a Timing Reference
Authors: DELACRETAZ ETIENNE , SOEJIMA KYOKO , GOTTIPATY VENKATESHWAR K. , BRUNCKHORST CORINNA B. , FRIEDMAN PETER L. , STEVENSON WILLIAM G.
Published: July 2003

DELACRETAZ, E., et al.: Single Catheter Determination of Local Electrogram Prematurity Using Simultaneous Unipolar and Bipolar Recordings to Replace the Surface ECG as a Timing Reference. Bipolar recordings eliminate much of the far‐field signal, while minimally filtered unipolar recordings contain substantial far‐field signal components. These properties may allow the onset of the unipolar recording to serve as a timing reference for the bipolar recording obtained from the same electrode catheter during mapping of focal atrial or ventricular tachycardias. Mapping and RF ablation were performed in 26 patients with focal ventricular tachycardia and 14 patients with focal atrial tachycardia. At 205 mapping sites, simultaneous recordings of (1) minimally filtered unipolar electrograms (0.5–500 Hz), (2) high pass filtered unipolar electrograms (100 Hz), and (3) filtered bipolar recordings (30–500Hz) were analyzed. The interval between the onset of the minimally filtered unipolar electrogram and the first peak of the bipolar electrogram (UniOn ‐ Bip) correlated closely with the timing of the local electrogram referenced to the surface ECG (r = 0.85, P < 0.001). Of 53 sites where RF ablation was performed, UniOn ‐ BiP was shorter at successful compared to unsuccessful sites (3.8 ± 3.5 vs 9.2 ± 5.2ms, P < 0.001) and was < 15 ms at all successful sites. In conclusion, the comparison of simultaneous unipolar and bipolar electrograms from a single catheter allows assessment of the prematurity of local electrograms from a focal source without the use of the P wave or QRS onset as a timing reference.
Incidence of Electromagnetic Interference in Implantable Cardioverter Defibrillators
Authors: KOLB CHRISTOF , ZRENNER BERNHARD , SCHMITT CLAUS
Published: July 2003

KOLB, C., et al.: Incidence of Electromagnetic Interference in Implantable Cardioverter Defibrillators. Electromagnetic interference (EMI) with ICDs can lead to temporary inhibition of the device or to inappropriate delivery of antitachycardia pacing and shocks. The incidence of interactions between electronic devices and the current generation of ICDs is not known. In a retrospective study of 341 patients (665 patient‐years) who underwent a regular follow‐up every 3 months, five episodes of EMI were detected in four different patients. The risk for receiving inappropriate shocks due to EMI is < 1% per year and patient. In conclusion, although inappropriate delivery of shocks by ICDs due to EMI rarely occurs, patient information should emphasize the avoidance of situations of possible interference. Further efforts concerning lead technology and detection algorithms are necessary to minimize the risk of EMI.
Left Atrial‐ and Left Ventricular‐Based Single Lead DDD Pacing
Authors: DE COCK CAREL C. , VAN CAMPEN C.M.C. , VOS D.H.S. , VISSER CEES A.
Published: July 2003

DE COCK, C.C., et al.: Left Atrial‐ and Left Ventricular‐Based Single Lead DDD Pacing. Single lead physiological pacing with right ventricular apex stimulation is feasible in patients with normal sinus node function and is associated with lower costs and a reduced complication rate. Left ventricular or biventricular pacing using the tributaries of the coronary sinus was reported to improve functional status and quality‐of‐life in patients with advanced congestive heart failure and intraventricular conduction delays. In addition, the proximal part of the coronary sinus has been successfully used for left atrial stimulation. The feasibility and pacing characteristics of left atrial‐ and left ventricular‐based temporary pacing using a conventional single pass lead were studied. The tip of the lead was advanced in a distal position of the lateral or posterolateral branches of the coronary sinus, providing a stable position of the middle and proximal electrode pair in the first 2–7 cm of the coronary sinus. A successful stable position was achieved in 13 of 21 consecutive attempts. Using overlapping biphasic (OLBI) stimulation, left atrial and left ventricular pacing threshold were 2.3 ± 0.6 and 2.5 ± 0.5 V, respectively. Acceptable sensing values were measured for P waves (4.1 ± 0.7 mV) and R waves (9.7 ± 3.9 mV). There was a good correlation between the diameter of the coronary sinus as assessed by quantitative coronary angiography at the level of the middle and proximal rings and atrial pacing threshold (r = 0.92, P < 0.0001). Thus, single lead left atrialand left ventricular‐based pacing is feasible although further development is necessary to increase the success rate for stable stimulation at both sites.
Clinical Use of Intracardiac Impedance: Current Applications and Future Perspectives
Authors: ARTHUR WAYNE , KAYE G.C.
Published: July 2003

ARTHUR, W., et al.: Clinical Use of Intracardiac Impedance: Current Applications and Future Perspectives. For over 40 years the measurement of intracardiac impedance has been proposed as a method of assessing the contractile state of the heart muscle. This technique requires the positioning of one or more intracavitary electrodes and the generation of an electric field from an alternating current source. Variations in the calculated impedance signal reflect changes in the ventricular blood pool volume adjacent to the electrodes. Intracardiac impedance measurement has been successfully developed as a research tool to assess myocardial contractility, and from this, clinical uses have evolved. Commercial rate responsive pacing systems use intracardiac impedance to assess the inotropic state of the heart. Further development of this technology might allow hemodynamic discrimination of cardiac arrhythmias.
Polymorphic Ventricular Tachycardia in a Woman Taking Cesium Chloride
Authors: SALIBA WALID , ERDOGAN OKAN , NIEBAUER MARK
Published: July 2003

SALIBA, W., et al.: Polymorphic Ventricular Tachycardia in a Woman Taking Cesium Chloride. A 47‐ year‐old patient presented with syncope and recurrent episodes of polymorphic ventricular tachycardia. She had evidence of prolonged QT interval by ECG and had been taking cesium as a dietary supplement. Correction of the hypokalemia and discontinuation of the cesium resulted in normalization of the QT interval during follow‐up with no further recurrence of ventricular arrhythmias. The use of this drug is potentially hazardous as it may induce fatal ventricular arrhythmias.
Prolonged QRS Duration Increases QT Dispersion But Does Not Relate to Arrhythmias in Survivors of Acute Myocardial Infarction
Authors: KIRCHHOF PAULUS , ECKARDT LARS , ARSLAN OYA , REINHARDT LUTZ , MÖNNIG GEROLD , FETSCH THOMAS , BREITHARDT GÜNTER , BORGGREFE MARTIN , HAVERKAMP WILHELM
Published: July 2003

KIRCHHOF P., et al.: Prolonged QRS Duration Increases QT Dispersion But Does Not Relate to Arrhythmias in Survivors of Acute Myocardial Infarction. QT dispersion has been suggested and disputed as a risk marker for ventricular arrhythmias after myocardial infarction. Delayed ventricular activation after myocardial infarction may affect arrhythmic risk and QT intervals. This study determined if delayed activation as assessed by (1) QRS duration in the 12‐lead ECG and by (2) late potentials in the signal‐averaged ECG affects QT dispersion and its ability to assess arrhythmic risk after myocardial infarction. QT duration, JT duration, QT dispersion, and JT dispersion were compared to QRS duration in the 12‐lead ECG and to late potentials in the signal‐averaged ECG recorded in 724 patients 2–3 weeks after myocardial infarction. Prolonged QRS duration (> 110 ms) and high QRS dispersion increased QT and JT dispersion by 12%–15% (P < 0.05). Presence of late potentials, in contrast, did not change QT dispersion. Only the presence of late potentials (n = 113) was related to arrhythmic events during 6‐month follow‐up. QT dispersion, JT dispersion, QRS duration, and QRS dispersion were equal in patients with (n = 29) and without arrhythmic events (QT disp 80 ± 7 vs 78 ± 1 ms, JT disp 80 ± 6 vs 79 ± 2 ms, mean ± SEM, P > 0.2). In conclusion, prolonged QRS duration increases QT dispersion irrespective of arrhythmic events in survivors of myocardial infarction. Presence of late potentials, in contrast, relates to arrhythmic events but does not affect QT dispersion. Therefore, QT dispersion may not be an adequate parameter to assess arrhythmic risk in survivors of myocardial infarction.
Clinical Relevance of Loss of Atrial Sensing in Patients with Single Lead VDD Pacemakers
Authors: CAMPEN VAN C.M.C. , DE COCK CAREL C. , HUIJGENS JEROEN , VISSER CEES A.
Published: July 2003

VAN CAMPEN, C.M.C., et al.: Clinical Relevance of Loss of Atrial Sensing in Patients with Single Lead VDD Pacemakers. During single lead VDD pacing, loss of atrial sensing is reported to be 2%–11% of patients in the literature. The impact on quality‐of‐life and exercise duration has never been established. This study tried to assess the clinical relevance of loss of atrial sensing in patients with single lead VDD pacemakers. Twenty‐one patients with total AV block were studied 3 months after single lead VDD pacemaker implantation. During a 6‐minute walk test, atrial undersensing was verified and adjusted to achieve undersensing in < 5% (group 1), 5%–10% (group 2), and > 10% (group 3). Patients were allocated to each group in a randomized double blind crossover design. At the end of each 2‐month study period all patients underwent symptom limited treadmill exercise testing. Subjective assessment of exercise difficulty was made using the Borg score, and quality‐of‐life assessment was performed using the Health Status Questionnaire. Exercise duration significantly decreased in group 3 (228 ± 50 s) as compared to group 1 (257 ± 42 s) and group 2 (250 ± 46 sec) with an increase in the Borg score. Quality‐of‐life was decreased for three subscales in group 3 as compared to group 1 and group 2. In conclusion, atrial undersensing of > 10% in patients with single lead VDD pacing was associated with a decrease in exercise duration and increase in the subjective severity score, in addition to a decrease in quality‐of‐life. Atrial undersensing of < 10% did not effect exercise test results or quality‐of‐life. Since all studies reported intact atrioventricular synchrony in ≥ 90% of patients, loss of atrial sensing is of limited clinical importance in these patients.
Comparison of the Rate Dependent Effects of Dofetilide and Ibutilide in the Newborn Heart
Authors: PICKOFF S. ARTHUR , STOLFI ADRIENNE
Published: July 2003

PICKOFF, A.S., et al.: Comparison of the Rate Dependent Effects of Dofetilide and Ibutilide in the Newborn Heart. This study compared the rate dependent changes in atrial and ventricular monophasic action potential duration in the newborn canine heart in response to two Class III antiarrhythmic agents: dofetilide, a pure Ikr blocker, and ibutilide, a Na+ channel opener. Newborn dogs were anesthetized with pentobarbital, vagotomized, and given propranolol to eliminate autonomic responses. A 4 Fr electrical catheter was placed in the right atrium for pacing. Monophasic action potential durations (APDs) at 90% repolarization (APD90) were recorded from the epicardial surface of the left ventricle and atrium with AgAgCl2 suction electrodes. APD90 was measured as cardiac cycle length was shortened by pacing, in the control condition and following two doses of dofetilide (n = 8) or ibutilide (n = 9). Slopes of the APD90 versus decreasing paced cycle length (PCL) relationships were then compared. Large dose dependent increases in atrial and ventricular APD90 were observed after dofetilide and ibutilide. In the neonatal atrium, there were no changes in the APD90 versus PCL relationship with either drug, indicating no rate dependency of drug effect. In contrast, in the ventricle, a steeper APD90 versus PCL slope was noted after dofetilide and ibutilide, indicating a significant loss of drug effect at faster heart rates (i.e., reverse rate dependency). In spite of probable different cellular mechanisms of action, the rate dependent characteristics of dofetilide and ibutilide are identical in the neonatal heart. There is no evidence of (reverse) rate dependency in the atrium, predicting that both agents would be effective at rapid atrial tachycardia rates. For both, however, marked reverse rate dependency is observed in the neonatal ventricle.
The World Survey of Cardiac Pacing and Cardioverter Defibrillators: Calendar Year 1997 ‐ Asian Pacific, Middle East, South America, and Canada
Authors: MOND HARRY G.
Published: July 2003

MOND, H.G., et al.: The World Survey of Cardiac Pacing and Cardioverter Defibrillators: Calendar Year 1997‐Asian Pacific, Middle East, South America, and Canada. A comprehensive cardiac pacing and ICD survey for the Asian Pacific region, Middle East, South America, and Canada was undertaken for calendar year 1997. Thirteen countries in the Asian Pacific region contributed to the survey. There were also two countries from the Middle East, three from South America, and Canada. Accurate numbers of new implants and replacements were obtained for cardiac pacemakers. In the Asian Pacific region, Japan with almost 20,000 implants, had the largest number of pacemaker implants, but Australia had the highest implant rate with 345 new implants per million population. However, Canada and Uruguay had higher new implant rates per million. The major indication for implantation of a cardiac pacemaker was high degree atrioventricular block. There was a high incidence of single chamber ventricular pacing in the developing countries of Asia. Only a few countries used substantial numbers of single lead VDD and AAIR pacing systems. Pacing leads were predominantly transvenous, bipolar, passive fixation, and steroid eluting. Activefixation leads were also used in the atrium. With ICD use, Australia had the highest new implant rate per million population. The major indications were sudden death and ventricular arrhythmias. A group of enthusiastic survey coordinators has now been established. It is hoped to continue physician and country recruitment, particularly in the Middle East and South American regions to establish a fully global experience of cardiac pacing and ICD use.
Transient Exit Block of a DDD Pacemaker with Unipolar Leads in Subcutaneous Emphysema Following Pneumothorax
Authors: MELZER CHRÍSTOPHE , WITTE H.J. , BAUMAN G. , THERES H.
Published: July 2003

MELZER, C., et al.: Transient Exit Block of a DDD Pacemaker with Unipolar Leads in Subcutaneous Emphysema Following Pneumothorax. This case report describes a transient pacemaker exit block due to subcutaneous emphysema following pneumothorax. Pneumothorax after pacemaker implantation is rare, but development of subcutaneous emphysema under such circumstances is even more uncommon. Exit block develops only with the use of unipolar leads; with implantation of bipolar leads, this complication cannot occur.
Levofloxacin Induced Polymorphic Ventricular Tachycardia with Normal QT Interval
Authors: PALTOO BRENDON , O'DONOGHUE SUSAN , MOUSAVI MORTEZA S.
Published: July 2003

PALTOO, B., et al.: Levofloxacin Induced Polymorphic Ventricular Tachycardia with Normal QT Interval. Polymorphic ventricular tachycardia (PVT) is a form of ventricular tachycardia characterized by QRS complexes that seem to change direction during the tachycardia. If associated with a prolonged QT interval, it is called torsades de pointes. In the absence of a congenital long QT syndrome, torsades is seen with certain drugs such as antiarrythmic agents (Class IA, IC, III), psychotropic medications, antidepressants, antihistamines, and electrolyte disturbances. We report the first case of polymorphic ventricular tachycardia with normal QT interval associated with the oral use of levofloxacin in the absence of other etiologies known to cause these arrhythmias.
Adenosine‐ and Verapamil‐Sensitive Ventricular Tachycardia in the Newborn
Authors: OZER SEMA , ALLEN STEVE , SCHAFFER MICHAEL S.
Published: July 2003

OZER, S., et al.: Adenosine‐ and Verapamil‐Sensitive Ventricular Tachycardia in the Newborn. Two neonates presented with sustained, monomorphic VT. Transesophageal electrophysiological studies demonstrated that the VTs were initiated with burst atrial pacing in one and noninducible in the other, and both terminated with burst atrial pacing and with adenosine. Oral verapamil suppressed the VTs in both. Following discontinuation of verapamil at 1 year of age, both children remain free of tachycardia recurrence at 3 and 4 years of age. These cases suggest that cAMP‐mediated triggered activity may be responsible for some VTs in infancy.
Relation Between the Rapid Focal Activation in the Pulmonary Vein and the Maintenance of Paroxysmal Atrial Fibrillation
Authors: WU TSU‐JUEY , LIANG KAE‐WOEI , TING CHIH‐TAI
Published: July 2003

WU, T.‐J., et al.: Relation Between the Rapid Focal Activation In the Pulmonary Vein and the Maintenance of Paroxysmal Atrial Fibrillation. This case report describes a patient with drug refractory paroxysmal atrial fibrillation (PAF). Rapid focal activations with multiple sharp spikes were continuously identified inside the left superior pulmonary vein (PV) during sustained AF. Among seven episodes of AF, cessation of rapid focal activations coincided with the conversion of AF to flutter (n = 4) or immediate AF termination (n = 3). Guided by sharp spikes in the PV, abrupt termination of AF occurred during radiofrequency energy application. Conclusively, rapid focal activations inside the PV are critical in AF maintenance. Cessation of these rapid focal activations underlies the mechanism by which AF converts to flutter.
Effect of Different Pacing Protocols on the Induction of Atrial Fibrillation in a Transvenously Paced Sheep Model
Authors: WILLEMS RIK , ECTOR HUGO , HOLEMANS PATRICIA , VAN DE WERF FRANS , HEIDBÜCHEL HEIN
Published: July 2003

WILLEMS, R. et al.: Effect of Different Pacing Protocols on the Induction of Atrial Fibrillation in a Transvenously Paced Sheep Model. In different animal models rapid atrial stimulation led to a shortening and maladaptation to rate of the atrial effective refractory period (AERP). This atrial electrical remodeling resulted in an increased vulnerability to atrial fibrillation (AF). These experimental findings formed the rationale for a stringent pursuit of sinus rhythm in patients with AF, since this would prevent or reverse atrial remodeling. This study tested the hypothesis that a reduction of arrhythmia burden would lead to a decreased vulnerability for AF. Different rapid atrial pacing protocols in a sheep model were used. During 15 weeks, 13 animals were continuously rapid paced and 7 animals were intermittently burst‐paced, resulting in rapid atrial activation during 100% versus 33 ± 4% of the time, respectively. In the continuously paced group, 77% of the animals developed sustained AF (i.e., >1 hour) versus only 29% in the burst‐paced group (P < 0.05). However, there was no difference in mean AERP shortening over time, nor maximal AERP shortening per animal, between both protocols. Minimal AERP was 103 ± 5 ms in the continuously paced group and 107 ± 5 in the burst‐paced group (P = NS). Significant changes could be identified in effect on P wave duration, AVN function, and atrial dilation. Conduction slowing was more pronounced in the continuously paced group with a maximal P wave duration of 136 ± 4 ms in this group versus 116 ± 5 in the burst‐paced group (P < 0.05). In the continuously paced group, the right atrial area significantly increased from 2.5 ± 0.1 cm2 at baseline to 4.2 ± 0.2 cm2. In the burst‐paced group there was no significant atrial dilatation (from 2.6 ± 0.1 to 2.8 ± 0.1 cm2). In conclusion, limiting atrial arrhythmia burden slowed the development of sustained AF in this sheep model. This was not mediated by a decreased influence on atrial refractoriness but seemed to be dependent on smaller changes in atrial conduction and dimensions.
A Simplified Approach to Temporary DDD Pacing Using a Single Lead, Balloon‐Tipped Catheter with Overlapping Biphasic Impulse Stimulation
Authors: FERGUSON JOHN DAWES , LEVER NIGEL , CHANNON KEITH MICHAEL , BASHIR YAVER
Published: July 2003

FERGUSON, J.D., et al.: A Simplified Approach to Temporary DDD Pacing Using a Single Lead, Balloon‐Tipped Catheter with Overlapping Biphasic Impulse Stimulation. Temporary DDD pacing offers significant hemodynamic benefits in emergency management of bradyarrhythmias but is underused because of its complexity (two leads) and unreliability. Single lead VDD pacing with atrial sensing via a floating dipole is feasible, but atrial pacing is limited by high thresholds and phrenic nerve stimulation (PNS). Overlapping biphasic impulse (OLBI) stimulation may avoid these problems. The authors designed a single lead balloon‐tipped catheter for temporary transvenous DDD pacing, incorporating noncontact atrial dipoles for OLBI stimulation. This catheter was deployed using fluoroscopic guidance in 74 patients (43 men, 31 women) with mean age 56.9 ± 17.0 years. Pacing parameters were assessed at implantation and follow‐up. The median procedural time was 6.6 (range 1.2–25.0) minutes and fluoroscopy time 1.9 (range 0.2–7.8) minutes. Stable VDD pacing was achieved in all cases. Atrial capture was achieved in 73 of 74 cases with both modes at maximum output but was restricted by PNS at outputs below atrial capture threshold in 3 of 74 cases with OLBI and 10 of 74 cases with standard bipolar mode (P = 0.04). At outputs ≥ 1.0 V above atrial threshold, reliable DDD pacing without PNS was achieved and maintained in 67 (91%) of 74 patients in OLBI compared to 53 (72%) of 74 patients in bipolar mode (P = 0.003). Pacing parameters were stable during follow‐up (median 53 hours, range 6–168 hours). In conclusion, the single lead catheter with OLBI stimulation allows temporary VDD and DDD pacing without PNS to be achieved in > 90% of patients. This rapid and convenient approach should facilitate DDD pacing in emergency settings.
Do Battery Depletion Indicators Reliably Predict the Need for Pulse Generator Replacement?
Authors: KINDERMANN MICHAEL , BERG MONIKA , PISTORIUS KAROLINE , SCHWERDT HOLGER , FRÖHLIG GERD
Published: July 2003

KINDERMANN, M., et al.: Do Battery Depletion Indicators Reliably Predict the Need for Pulse Generator Replacement? The aim of this study was to test the validity of battery depletion indicators to forecast end of service (EOS) in dual chamber pulse generators (PG). Two additional approaches for prediction of EOS were evaluated as well: the real‐time telemetry of cell impedance and a battery stress test (BST) that used a transitory increase in pacing rate. The study population consisted of 119 patients with Intermedics dual chamber PG models Cosmos II and Relay, in which cell impedance had exceeded 2.5 kΩ. The patients were followed in 6‐month intervals. If the interrogation of the PG or the BST prompted the appearance of the intensified follow‐up indicator (IFI), the next follow‐up was scheduled within 2 months. PG replacement was performed on physician's discretion or immediately on appearance of the elective replacement indicator (ERI), regardless of the method of ERI provocation. During a period of 2 years and 9 months, 33 patients underwent PG replacement. Out of 21 patients with positive ERI indicators, only 5 had positive warning indicators of approaching battery depletion in the preceding follow‐up (IFI during BST, n = 4; ERI during BST n = 1). The majority of patients (n = 16, 76%) revealed ERI without prior activation of IFI, neither spontaneous nor during the BST. Four of these 16 ERI‐positive patients had cell impedance values far below the ERI limits of the manufacturer. Based on battery depletion indicators, an exact prediction of EOS of dual chamber pacemakers is not possible. Measuring battery impedance allows for a statistical estimation of remaining service life but it may be misleading in the individual case. A BST that is based on a temporary increase of pacing rate is invalid in forecasting battery depletion. As activation of the ERI can trigger an abrupt change to the VVI backup mode, pacemaker dependent patients with low programmed basic pacing rates may be hemodynamically compromised by an unexpected activation of ERI. Close monitoring intervals and PG replacement before appearance of the ERI is recommended in those patients.
Incidence of T Wave Alternation After Acute Myocardial Infarction and Correlation with Other Prognostic Parameters: Results of a Prospective Study
Authors: SCHWAB JÖRG OTTO , WEBER STEFAN , SCHMITT HEIKO , STEEN‐MUELLER MARY‐KAY , COCH MICHAEL , TILLMANNS HARALD , BECKER MARC , LENZEN CHRISTOPH , WALDECKER BERND
Published: July 2003

SCHWAB, J.O., et al.: Incidence of T Wave Alternation After Acute Myocardial Infarction and Correlation with Other Prognostic Parameters: Results of a Prospective Study. Tachycardia induced alternation of the T wave (TWA) has been associated with arrhythmia morbidity in mixed patient populations. However, less is known concerning the general incidence of TWA and its usefulness in risk stratification early after acute myocardial infarction (MI). TWA was prospectively and systematically assessed in 140 consecutive patients 15 ± 6 days after acute MI and prior to discharge. Results of TWA measurements were compared to other noninvasive risk markers, LV function, and coronary angiography. Sustained TWA was present at rest or inducible during exercise in 27% of patients. The patient‐specific heart rate for the onset of TWA was 98 ± 9 beats/min. After multivariate analysis, TWA correlated with age (P = 0.02) and LV function (P = 0.002) and occurred more often in patients after nonanterior MI (P = 0.03). Acute results of Holter monitoring, late potentials by signal‐averaged ECG, and heart rate variability were unrelated to the TWA status. During follow‐up (451 ± 210 days) two major arrhythmic events occurred. The incidence of TWA early after MI is about 25%. TWA is related to age and LV function but not to other common arrhythmia markers. Although TWA does not appear to be related to excessive cardiac morbidity, evaluation of the prognostic significance of TWA requires further study.
Studies on the Prevalence of Complicated Atrial Arrhythmias, Flutter, and Fibrillation in Patients with Reciprocating Supraventricular Tachycardia Before and After Successful Catheter Ablation
Authors: MIYAMOTO KEN‐JIROH , TSUCHIHASHI KAZUFUMI , UNO KIKUYA , SHIMOSHIGE SHIN‐YA , YOSHIOKA NOBUHIRO , DOI ATSUSHI , NAKATA TOMOAKI , SHIMAMOTO KAZUAKI
Published: July 2003

MIYAMOTO, K.‐J., et al.: Studies on the Prevalence of Complicated Atrial Arrhythmias, Flutter, and Fibrillation in Patients with Reciprocating Supraventricular Tachycardia Before and After Successful Catheter Ablation. Atrial flutter and AF are complications in approximately 30% of cases of paroxysmal supraventricular tachycardia (PSVT)‐indicated catheter ablation, and it is of interest to determine if therapeutic modification for PSVT would eliminate combined atrial tachyarrhythmia like atrial flutter and AF. The aim of this study was to determine the incidence and the risk of atrial tachyarrhythmias after catheter ablation of PSVT. A total of 152 patients (age range 12–74, mean 41 ± 17 years) with accessory pathway (n = 106) and/or dual atrioventricular nodal conduction (n = 46) were enrolled in a 2‐year follow‐up program after successful catheter ablation. Possible risks on clinical background (age, sex, PSVT duration, hemodynamic instability during attacks), premature atrial contraction (PACs) on Holter monitoring, echocardiographic left atrial size, and electrophysiological property (insertion site, conduction type, effective refractory period) were evaluated. Atrial flutter and AF were complications in 53 (35%) of the subjects, who were elderly and had a longer PSVT history with a larger left atrial dimension and frequent PACs; however, the electrophysiological properties were similar. After a 2‐year follow‐up period 36 (24%) of the patients still exhibited PAC runs, including 13 (9%) with atrial flutter and AF, each one of whom were complicated with nonlethal cerebral thromboembolism and congestive heart failure. Multiple‐logistic‐regression analysis revealed that advanced age (≥ 41 years, P = 0.0152) and frequent PACs (≥ 1% of total daily QRS counts, P = 0.0426) on Holter monitoring are the risk factors of PAC runs and/or atrial flutter and AF. In conclusion, successful ablation for PSVT is thought to be beneficial for preventing atrial flutter and AF. However, careful follow‐up to monitor for the recurrence and atrial flutter and AF related complications, especially in patients of solitary atrial flutter and AF without reciprocating tachycardia and with frequent PAC.
Correlation of Impedance Minute Ventilation with Measured Minute Ventilation in a Rate Responsive Pacemaker
Authors: COLE CHRISTOPHER R. , JENSEN DONALD N. , CHO YONG , PORTZLINE GERALD , CANDINAS RETO , DURU FIRAT , ADLER STUART , NELSON LINDA , CONDIE CATHERINE , WILKOFF BRUCE L.
Published: July 2003

COLE, C.R., et al.: Correlation of Impedance Minute Ventilation with Measured Minute Ventilation in a Rate Responsive Pacemaker. Although rate responsive pacing based on impedance minute ventilation (IMV) is now standard, there is almost no data confirming the relationship between IMV from an implanted pacemaker and measured minute ventilation (VE) during exercise. Nineteen completely paced adults implanted with Medtronic Kappa 400 pacemakers underwent symptom‐limited maximal metabolic treadmill testing using a modified Minnesota Pacemaker Response Protocol. Minute ventilation (VE, L/min) was simultaneously measured using the flowmeter of a respiratory metabolic gas analysis system and the transthoracic impedance minute ventilation circuitry of the pacemaker. Correlation coefficients (r) were used to find the best fit line to describe the relationship between the two measurements. Mean (± SD) r values for the first, second, and third order polynomial equations and for log and exponential equations were: 0.92 ± 0.08, 0.94 ± 0.04, 0.95 ± 0.04, 0.91 ± 0.06, and 0.91 ± 0.07, respectively. None of the r values were statistically different from the first order equation. Transthoracic IMV as measured by the Medtronic Kappa 400 is closely correlated to measured minute ventilation and is represented well by a first order (linear) equation.
Successful Surgical Ablation of Sustained Ventricular Tachycardia Associated with Mitral Valve Prolapse Guided by a Multielectrode Basket Catheter
Authors: VAN DESSEL PASCAL F. , VAN HEMEL NORBERT M. , VAN SWIETEN HENRI A. , DE BAKKER JACQUES M. , JESSURUN EMILE R.
Published: July 2003

VAN DESSEL, P.F., et al.: Successful Surgical Ablation of Sustained Ventricular Tachycardia Associated with Mitral Valve Prolapse Guided by a Multielectrode Basket Catheter. Ventricular tachycardia occurs frequently in patients with mitral valve prolapse. If antiarrhythmic drug therapy fails or mitral valve surgery is indicated, concomitant arrhythmia surgery may be considered. This report describes the first clinical use of an atrial transseptally inserted multielectrode basket catheter, placed across the mitral valve, to guide intraoperative mapping and ablation of monomorphic sustained ventricular tachycardia in association with mitral valve prolapse. Endocardial covering and signal quality of this percutaneous mapping catheter were of good quality, allowing an accurate localization of the site of origin of the tachycardia.
Late Fatal Right Ventricular Perforation as Complication of Permanent Pacing Leads
Authors: GARCÍA‐BOLAO IGNACIO , TEIJEIRA RAFAEL , DÍAZ‐DORRONSORO INÉS
Published: July 2003

GARCÍA‐BOLAO, I., et al.: Late Fatal Right Ventricular Perforation as Complication of Permanent Pacing Leads. Perforation of the right ventricle during placement of pacing electrodes is a well‐documented complication. Most of these perforations occur intraoperatively and rarely cause symptoms. This case report describes a fatal cardiac perforation that occurred 10 days after implantation of a permanent cardiac pacemaker. This complication should be considered as one of the potential mechanisms responsible for the high rate of sudden death observed in paced patients during the first year after pacemaker implantation.
Sinus Node Reentrant Tachycardia in a Neonate
Authors: OZER SEMA , SCHAFFER MICHAEL
Published: July 2003

OZER, S., et al.: Sinus Node Reentrant Tachycardia in a Neonate. A neonate presented with paroxysmal atrial tachycardia. Transesophageal electrophysiological study demonstrated sinus node reentrant tachycardia, which was induced and terminated with programmed electrical stimulation. The tachycardia would also terminate in the atrium with adenosine. Empiric digoxin treatment successfully suppressed the tachycardia which then recurred with discontinuation of the digoxin at 6 weeks. The child was retreated with digoxin with no further recurrences for 18 months. Transesophageal electrophysiological study at 20 months showed prolonged sinus node recovery times and no inducible arrhythmias. The child has remained free of arrhythmias at 4 years.
Unexpected ICD Pulse Generator Failure Due to Electronic Circuit Damage Caused by Electrical Overstress
Authors: HAUSER ROBERT G. , HAYES DAVID L. , ALMQUIST ADRIAN K. , EPSTEIN ANDREW E. , PARSONNET VICTOR , TYERS G. FRANK O. , VLAY STEPHEN C. , SCHOENFELD MARK H.
Published: July 2003

Hauser, R., et al.: Unexpected ICD Pulse Generator Failure Due to Electronic Circuit Damage Caused by Electrical Overstress. Because it is a lifesaving device, the unexpected failure of an ICD can be catastrophic. We report ICD electronic circuit failure due to electrical overstress damage (EOS) to the high voltage hybrid circuit and other electronic components in a series of ICD pulse generator models. Data were obtained from the Multicenter Registry of Pacemaker and ICD Pacemaker and Lead Failures, and from the manufacturers' adverse event reports, that were in the FDA's Manufacturer and User Facility Device Experience (MAUDE) database. Of 16 nonbattery Guidant/CPI ICD pulse generator failures reported to the registry, 6 (38%) have been confirmed by the manufacturer to be EOS related, and Guidant/CPI has reported 273 such failures to the FDA as of 12/29/00. The signs of failure included loss of telemetry and inability to deliver therapy, and some patients have experienced serious adverse events. Hybrid circuit damage may have occurred during capacitor charging or reform, and the majority appears to have happened during normal ICD function. While the incidence of this problem is unknown, a management strategy should be adopted that includes routine follow‐up every 3 months and device evaluation after a shock or exposure to external defibrillation or electrosurgical devices. This study suggests that additional data are needed to determine the incidence of this problem, and that our present methods for monitoring the performance of ICDs following market release are inadequate.
Dispersion in Ventricular Repolarization in Patients with Severe Intraventricular Conduction Disturbances
Authors: ENGLUND ANDERS , ANDERSSON MATS , BERGFELDT LENNART
Published: July 2003

ENGLUND, A., et al.: Dispersion in Ventricular Repolarization in Patients with Severe Intraventricular Conduction Disturbances. Increased dispersion of repolarization, measured invasively or by QT interval measurements, is associated with an increased risk for ventricular arrhythmias and sudden death. Most studies on this issue have included patients with normal intraventricular conduction, and it is not known if this finding has a predictive value also in patients with intraventricular conduction disorders. An invasive electrophysiological study, including programmed ventricular stimulation and assessment of effective refractory periods at two RV sites, was performed in 103 patients with bifascicular block (mean age 67 ± 12 years). QT dispersion was measured from standard 12‐lead ECGs. In patients with inducible sustained polymorphic VT or VF the dispersion in refractoriness between the two RV sites was significantly greater (46 ± 11 ms, n = 13) than in noninducible patients (14 ± 14 ms, n = 84) and in patients with inducible sustained monomorphic VT (16 ± 5 ms, n = 6) (P < 0.01). Similarly, QT dispersion was 104 ± 46 ms, 66 ± 31 ms, and 77 ± 33 ms, respectively, in the three groups (P < 0.05). Dispersion in repolarization, neither measured invasively nor by QT interval measurements, predicted sudden death, all cause mortality, or ventricular arrhythmia during a mean follow‐up period of 3 years. In patients with bifascicular block, there is a relation between the degree of dispersion of ventricular repolarization and the inducibility of polymorphic ventricular arrhythmia, but this outcome did not occur during follow‐up.
Mapping the Organization of Atrial Fibrillation with Basket Catheters Part II: Regional Patterns in Chronic Patients
Authors: MICHELUCCI ANTONIO , BARTOLINI PIETRO , CALCAGNINI GIOVANNI , CENSI FEDERICA , COLELLA ANDREA , MORELLI SANDRA , PADELETTI LUIGI , PIERAGNOLI PAOLO , BARBARO VINCENZO
Published: July 2003

MICHELUCCI, A., et al.: Mapping the Organization of Atrial Fibrillation with Basket Catheters Part II: Regional Patterns in Chronic Patients. The aim of this study was to investigate the spatial patterns of organization of fibrillation in the right atrium using bipolar recordings from a basket catheter in a population of 17 patients with persistent AF. The number of occurrences (NO) (i.e., the number of points laying on the baseline) was used as an objective measure of organization. This parameter significantly matches Wells' criteria for the classification of bipolar recordings during AF. The anatomic correspondence of the splines with eight atrial regions (namely anterior free wall, lateral free wall, posterolateral free wall, posterior free wall, posterior atrial septum, atrial septum, tricuspid valve, and anterior tricuspid valve) was assessed by fluoroscopic projections and electrogram morphology. Each region was further divided into high, mid‐high, mid‐low, and low segments. It was observed that individual and well‐defined patterns of organization characterize the electrical activity of the right atrium in patients with persistent AF. When observed over 10 minutes, these patterns are rather stable in time. In each patient, the NO measurements were significantly different in the various right atrium regions (P < 0.0001 for all patients, Friedman test). The NO averaged over the population was significantly different among the regions (P < 0.001, Kruskal‐Wallis test), owing to a common disorganized pattern observed in the tricuspid valve and anterior tricuspid valve regions. When these regions were removed from the analysis, the differences among the remaining regions were not statistically significant (P = 0.77). In conclusion, the quantitative assessment of organization in the entire right atrium showed an individual rather than common distribution. This may have implications in the choice of regions candidate for ablation.
Young at Heart: Understanding the Unique Psychosocial Adjustment of Young Implantable Cardioverter Defibrillator Recipients
Authors: SEARS SAMUEL F. , BURNS JASON L. , HANDBERG EILEEN , SOTILE WAYNE M. , CONTI JAMIE B.
Published: July 2003

SEARS, S.F. JR., et al.: Young at Heart: Understanding the Unique Psychosocial Adjustment of Young Implantable Cardioverter Defibrillator Recipients. This article reviews the data related to psychosocial adjustment of young ICD recipients, postulates theories to explain potential adjustment difficulties to ICD therapy experienced by younger recipients, and suggests clinical management techniques for addressing the unique psychosocial concerns of young ICD recipients. Studies of young ICD recipients suggest that a wide range of psychosocial adjustment issues are prominent in the post‐ICD implantation period and that the issues may be different from older ICD recipients. The disability‐stress‐coping model and the transactional‐stress‐coping model are postulated as explanations for the unique adjustment concerns of children and adolescents with ICDs. Social comparison theory is also applied to the concerns of young adults with ICDs such that they often lack same age peers to compare experiences with cardiac difficulties. Brief, clinic‐based interventions by health care providers, like a screening and referral heuristic and an “ICD Buddy” system, are suggested to increase effective coping and decrease social isolation for young ICD recipients.
Waveform Optimization for Internal Atrial Defibrillation: Effects of Waveform Rounding, Phase Duration, and Voltage Swing
Authors: KIDWAI BAKHTIAR J. , ALLEN J. DESMOND , HARBINSON MARK T. , MCINTYRE ALLISTER , ANDERSON JOHN , ADGEY A.A. JENNIFER
Published: July 2003

KIDWAI, B.J., et al.: Waveform Optimization for Internal Atrial Defibrillation: Effects of Waveform Rounding, Phase Duration, and Voltage Swing. The aim of this study was to compare the efficacy of internal atrial defibrillation by conventional truncated exponential biphasic waveforms with and without waveform rounding (1–2 phases) and to determine optimal duration for this novel double rounded waveform. Atrial fibrillation, induced by rapid electrical stimulation, was converted by internal shocks through defibrillation catheters (lateral right atrium and coronary sinus) in anesthetised sheep. Rounding the leading edges of the conventional biphasic waveform (Ventritex HVS‐02; settings 100/–50 V, 150/–70 V, and 200/–100 V; n = 8) reduced delivered peak and trough voltages, currents, and energy (by ≥ 21%, P < 0.001; for double (both phases) rounded) without decreasing cardioversion success. At 100/–50 V the efficacy of single (first phase) rounded (53 ± 13%; mean ± SEM) and double rounded (59 ± 11%) shocks was similar to the conventional waveform (56 ± 14%). Double rounded waveform (phase durations 1–20 ms) efficacy was optimum at 6–10 ms phase duration (100% success at 10–ms phase duration; 1.52 ± 0.04 J delivered energy; n = 6). Successful cardioversion by conventional, single rounded, and double rounded biphasic waveforms (duration 6 ms each phase), conventional monophasic, rounded monophasic (duration 12 ms), and a damped sine waveform correlated strongly with peak‐to‐trough voltage swing within the waveform (r = 0.882; P < 0.01; n = 8). For internal atrial defibrillation, rounding both phases of the conventional biphasic waveforms, the double rounded waveform, permits similar efficacy to the conventional truncated exponential biphasic waveform at reduced peak voltage, current, and delivered energy. Optimum phase duration is 6–10 ms (tested range 1–20 ms).