bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of D‐Net (European GSM‐Standard) Cellular Phones on Pacemaker Function in 50 Patients with Permanent Pacemakers
Authors: WILKE ANDREAS , GRIMM WOLFRAM , FUNCK REINHARD , MAISCH BERNHARD
Published: July 2006

The widespread use of cellular phones in the last years has prompted some recant studies to suggest an interference of pacemaker function by cellular phone usage. To determine the risk of pacemaker patients using D‐net cellular phones, we tested 50 patients with permanent pacemakers after routine pacemaker check by short phone calls using a cellular phone (Ericsson, D‐net, frequency 890–915 MHz, digital information coding, equivalent to the European Croupe Systemes Mobiles standard). A six‐channel surface ECG was continuously recorded from each patient to detect any interactions between pacemakers and cellular phones. Phone calls were repeated during the following pacemaker settings: (1) preexisting setting; (2) minimum ventricular rate of 90 beats/min and preexisting sensitivity; and (3) minimum ventricular rate of 90 beats/min and maximum sensitivity without T wave oversensing. Only 2 (4%) of 50 patients repeatedly showed intermittent pacemaker inhibition during calls with the cellular phone. Both pacemakers had unipolar sensing. Therefore, although interactions between cellular phone use and pacemaker function appear to be rare in our study, pacemaker dependent patients in particular should avoid the use of cellular phones.
Short‐ and Long‐Term Results with an Active‐Fixation, Bipolar, Polyurethane‐Insulated Atrial Pacing Lead
Authors: GLIKSON MICHAEL , VON FELDT LINDA K. , SUMAN VERA J. , HAYES DAVID L.
Published: July 2006

Since 1989, 136 Medtronic 4058 and 4058M bipolar atrial screw‐in leads have been implanted at the Mayo Clinic. Early lead related complications included dislodgment in 4 (2.9%). Over a median follow‐up time of 14.4 months (1 day to 3.3 years), there were 11 lead related complications (undersensing, failure to capture, diaphragmatic pacing, and gross lead dislodgment). Chronic complications resulted in reoperations in four patients (2.9%). Of 77 patients in whom pacing thresholds were measured between 2 and 4 months after implantation, 9 (11.7%) and 2 (2.6%) had high pacing thresholds and very high thresholds, respectively. The Kaplan‐Meier estimate of the probability of 1‐year complication‐free lead survival was 93.5%. There were no lead material failures. We conclude that the 4058/4058M lead implanted in the atrial position has favorable acute and chronic performance data, with a tendency toward high pacing thresholds at 3 months. The cause of this phenomenon and its course over time should be further evaluated.
The “Smart” Escape Interval: An Innovative Approach to Cardiac Pacing
Authors: TELLINI LUIGI
Published: July 2006

This study attempts to improve cardiac pacing by utilizing a new strategy based on integrative rather than substitutive stimulation. This type of cardiac stimulation does not compete with the sinoatrial oscillator and can position the stimulated beat at the expected time. This can be achieved by locking the pacemaker's escape interval to the sinus cycle, making it a variable parameter continuously updated on the preceding cycle. When the rate and rhythm are regular, the pacemaker's activity is completely “concealed,” although the escape interval continues to be updated. When a sudden conduction block occurs, the pacemaker positions the stimulated beat where we would expect the natural beat to be. When the natural heart rate goes outside the locking field by being too low, the pacemaker loses the lock and returns to its free‐running frequency. However, an alternative choice is to pass to “overdrive” stimulation: this occurs when the escape interval is locked in phase to the sinoatrial oscillator, but is set to have a period equal to one‐half or one‐third of the sinus cycle. When applied to sinus bradycardia, this can multiply the natural heart rate by 2 or 1.5, but the rate responsiveness is maintained because it is locked to a natural “sensor.” When applied to bicameral pacing, the phase‐locked pacemaker marks a jump from atrial triggered stimulation to a “true” atrial synchronous stimulation. In this novel situation, the ventricular stimulator remains relatively independent with respect to the atrial rhythm while the tracking of the sinusal drive is ensured. This feature could prove useful in reducing both the incidence of pacemaker mediated tachycardias and effects such as myopotential interference.
Intrapatient Comparison of Atrial and Ventricular Sensing, Pacing Threshold, and Impedance: Benefits with Steroid‐Eluting Leads
Authors: MORACCHINI PIER VITTORIO , TESORIERI MARIA CRISTINA , GIULIANI MAURO , ALFANO GIUSEPPE , DE SETA FRANCESCO , BOSCHI SILVANA
Published: July 2006

We compared the atrial and ventricular bioelectrical effects relating to pacing threshold, pacing impedance, and pacing energy in each of 58 patients to determine the importance of pacing impedance in safe low energy stimulations. The study was conducted during 4 years of follow‐up. Of the 58 patients in our study, 31 were stimulated in both chambers with steroid‐eluting leads (Capsure 4503 and 4003) and 27 with platinum electrode catheters (Target Tip 4511 and 4011). The two groups were homogeneous in sex, age, cardiopathy, and reason for implant. At 6 months, the mean impedance values for the Target Tip were: 358 ± 72 Ω for the atrium and 443 ± 87 Ω for the ventricle (P < 0.00002): after 1 year, atrium = 386 ± 77 Ω, ventricle = 439 ± 42 Ω (P < 0.04); at 2 years, atrium = 409 ± 86 Ω, ventricle = 510 ± 94 Ω (P < 0.0001); at 3 years, atrium = 428 ± 81 Ω, ventricle = 494 ± 67 Ω (P < 0.02); and at 4 years, atrium = 424 ± 71 Ω and ventricle = 501 ± 69 Ω (P < 0.003). The mean impedance value (for the Capsure) was: atrium = 351 ± 43 Ω, ventricle = 431 ± 81 Ω at 6 months (P < 0.03); at 1 year, atrium = 359 ± 38 Ω, ventricle = 446 ± 83 Ω (P < 0.01); at 2 years, atrium = 304 ± 124 Ω, ventricle = 459 + 108 Ω (P <0.0003); at 3 years, atrium = 359 ± 108 Ω, ventricle = 461 ± 89 Ω (P < 0.02); and at 4 years, atrium = 419 ± 133 Ω and ventricle = 515 ± 75 Ω (P < 0.03;. In view of the chronic threshold, low energy stimulation was used at follow‐up. The mean low energy stimulation values programmed for Target Tip were: atrium = 2.5 V/0.35 ms, ventricle = 2.5 V/0.30 ms; for Capsure, atrium = 2.5 V/0.25 ms, ventricle = 2.5 V/0.25 ms. The mean stimulation energy value was 31% higher in the atrium than in the ventricle with Capsure leads, and 39% higher with Target Tip. Pacing impedance was lower in the atrium than in the ventricle with both leads. Energy consumption in the atrium is significantly greater than in the ventricle with both leads, particularly with Target Tip.
The Heart Rate Response to Carotid Artery Massage in a Sample of Healthy Elderly People
Authors: JEFFREYS MICHAEL , WOOD DAVID A. , LAMPE FIONA , WALKER FIONA , DEWHURST GRAEME
Published: July 2006

Carotid artery massage was carried out in a cross‐section of 95 healthy elderly subjects (51 men and 44 woman, mean age of 74 years) to assess the heart rate response and associated symptoms. These subjects were drawn from a larger group of randomly selected healthy elderly people living in Southampton. They had no history of myocardial infarction or stroke and were not taking any drugs that might enhance the carotid sinus reflex. A continuous distribution of response to carotid artery massage was seen with a median percent change in RR interval of 11.6% (IQR 22.9%); 66% had a percent change in RR interval of < 20%, 90% had a change of < 50%, and 9.5% a change of > 100%. Carotid sinus hypersensitivity (sinus arrest > 3 s) was found in 4 previously asymptomatic subjects; a prevalence of 4.2% (95% CI 1.2%–10.4%), and this was associated with dizziness in 2 of these 4 subjects. Dizziness also occurred in one other subject who had a change in RR interval of 178%, The definition of an abnormal carotid sinus reflex is arbitrary given the continuous RR interval response to carotid artery massage. In diagnosing carotid sinus syndrome, the RR interval response to carotid artery massage alone is not sufficient, as this maneuver must also reproduce the patient's presenting symptoms.
Clinical Utility of Routine Transthoracic Echocardiographic Studies After Uncomplicated Radiofrequency Catheter Ablation: A Prospective Multicenter Study
Authors: PIRES LUIS A. , HUANG SHOEI K. STEPHEN , WAGSHAL ALAN B. , MAZZOLA FRANK , YOUNG PATRICK G. , MOSER SUZAN ,   THE ATAKR INVESTIGATORS GROUP
Published: July 2006

Unsuspected cardiac complications have been occasionally identified on postablation echocardiographic studies; however, the clinical utility of route echocardiographic studies following uncomplicated radiofrequency catheter ablation procedures has not been established. Two‐dimensional/Doppler echocardiographic studies obtained preablation (within 3 months of the procedure) in 355 consecutive patients (180 males and 175 females, mean age 37 ± 21 years) were compared to postablation (within 24 hours of the procedure) studies obtained after a total of 387 uncomplicated RF catheter ablation procedures for AV node slow pathway (n = 120), accessory AV pathways (n = 214), and complete AV junction (n = 39). Postablation studies identified 6 new cases (1.5%) of new wall motion abnormalities, and 3 additional patients had septal wall motion abnormalities during ventricular pacing. LVEF remained unchanged from baseline (62 ± 10 vs 62 ± 11). A small pericardial effusion was detected after 11 procedures (2.8%), and there were 9 (2.3%), 21 (5.4%), and 20 (5.2%) new findings of mild (1 +) aortic, mitral, and tricuspid regurgitation, respectively; and no cases of significant valvular dysfunction in any patient. There were no new cases of cavity thrombus. There was no clear relationship between postablation echocardiographic findings and the type and approach to ablation, and no patient had any clinical sequelae possibly related to any of the new echocardiographic findings during a mean follow‐up of 15 ± 6.0 months (range 1–26 months). Routine transthoracic echocardiographic studies after uncomplicated RF catheter ablation procedures identify occasional minor abnormalities that (1) may or may not be procedure related, (2) are of no apparent clinical consequence, and (3) thus appear to be of limited value.
Torsades de Pointes from Terfenadine and Sotalol Given in Combination
Authors: FEROZE HAMID , SURI RANJIT , SILVERMAN DAVID I.
Published: July 2006

A patient receiving sotalol developed recurrent torsades de pointes following the addition of terfenadine (Seldane) to her medical regimen. A 71‐year‐old woman with a history of atrial fibrillation successfully suppressed with sotalol, 80 mg bid, was started on terfenadine, 60 mg bid. Eight days later, she developed repeated self‐terminating episodes of torsades de pointes. Sotalol and terfenadine were discontinued, and no further arrhythmia was observed after 72 hours of temporary pacing was discontinued.
VDD Pacing with Single Lead in a Heart Transplant Recipient: Case Report
Authors: FERNÁNDEZ MARCELO SANMARTÍN , PULPÓN LUIS ALONSO , OTEO JUAN FRANCISCO , PINEDA CARMEN EXPÓSITO , BARRIO ELENA ESPAÑA , LOZANO IGNACIO FERNANDEZ , MELCHOR LORENZO SILVA , FIZ SANTIAGO SERRANO , de ARTAZA ANDRADE MANUEL
Published: July 2006

Permanent pacemaker implantation is required in a large number of transplantation patients principally because of sinus node dysfunction of the donor atrium. The most suitable mode of pacing in these cases is still subject to controversy. We describe one case of a single lead system of VDD stimulation and sensing of the recipient atrial signal in a 32‐year‐old patient with posttransplant symptomatic sinus node dysfunction. Physiological adaptation of rate was achieved with recovery of normal receptor sinus node function. (PACE 1996; 19:1522–1523).
Implantation of a Nonthoracotomy Defibrillator Using a Second Defibrillator Patch in the Abdominal Pocket
Authors: VERDINO RALPH J. , HANNAN ROBERT L. , TRACY CYNTHIA M. , SOLOMON ALLEN J.
Published: July 2006

Successful implantation of a biphasic nonthoracotomy implantable cardioverter defibrillator may not be achieved with a conventional system. We describe a successful device implantation using a pectoral and abdominal patch electrode system.
Erosion of Internal Cardioverter Defibrillator Pocket and Migration of Pulse Generator into the Peritoneal Cavity
Authors: CHITKARA VINAY K. , VLAY STEPHEN C.
Published: July 2006

ICD therapy for life‐threatening arrhythmias is well established. As more patients are treated, the incidence of recognized and new complications may increase. We report ICD pocket erosion and migration of the pulse generator into the peritoneal cavity in two patients.
Upright Tilt Test: Correlation Between Results and Patient Clinical Features
Authors: FOLINO ANTONIO FRANCO , BUJA GIANFRANCO , MARTINI BORTOLO , BASSAN LUCIANO , NAVA ANDREA
Published: July 2006

The aim of our study was to analyze how the clinical history and the main clinical characteristics of patients suffering from loss of consciousness may influence the results of the upright tilt test. A series of 745 patients (333 males, 412 females; mean age 44 ± 18 years) with recurrent episodes of syncope or presyncope underwent complete clinical and noninvasive laboratory examination, including vagal maneuvers and upright tilt test (60° for 45 min). Cardiological and neurological findings were normal in every case. Upright tilt test was positive in 462 patients (62%). Patients with presyncope showed a lower positivity compared to patients with syncope (70.2% vs 42.9%, P < 0.001). Younger patients (< 25 years) displayed highest upright tilt test positivity (68.5%), while familial occurrence of syncope or presyncope, results of vagal maneuvers, and different gender did not correlate with the results of the test. The time interval between the last syncopal episode and the day of upright tilt test negatively influenced the proportion of positive tests (> 30 days = 45.1 % vs < 30 days = 77.2%; P < 0.001). Patients with more than three syncopal episodes in the 2 months preceding the test showed a higher upright tilt test positivity (83.9% vs 64.5%, P < 0.001). In conclusion, upright tilt test seems to be more sensitive in young patients with syncopal episodes during symptomatic periods. These findings suggest both an individual and temporal variability in autonomic nervous system activity, the implication of which are relevant to the indications for testing as well as the analysis of results.
Radiofrequency Ablation of Atrial Flutter and Atrial Tachycardias in Patients with Permanent Indwelling Catheters
Authors: NEWBY KEITH H. , ZIMERMAN LEANDRO , WHARTON J. MARCUS , KENT VIRGINIA , KEARNEY MARGARET , BRANDON M. JOAN , NATALE ANDREA
Published: July 2006

The presence of chronic indwelling leads in the area targeted for RF ablation may pose a technical challenge and reduce the chance of success of the ablation. In addition, application of lesions in close proximity to pacemaker leads or other permanent catheters could affect their function. Fourteen patients referred for RF ablation of atrial flutter/fibrillation and atrial tachycardia, who had a permanent dual chamber pacemaker (10 patients), ICD (1 patient), or both (3 patients) were studied to assess the safety, efficacy, and effects of the ablative procedure on device function. Lead impedance, R and P wave amplitude, and pacing threshold of the defibrillator and pacemaker were measured before and after ablation. The procedure was successful in all patients. In one patient who underwent both atrial flutter and atrial fibrillation ablation, the atrial pacing threshold increased from 1.0 preablation to 2.0 V postablation. No P wave was detectable after ablation. In another patient, the P wave amplitude went from 4.0 to 2.0 mV postablation. In both patients the device converted to the power reset mode. No changes were observed in the remaining patients. Postablation defibrillator testing showed no malfunction. Follow‐up reinterrogation of the devices revealed no alterations. In conclusion: (1) RF ablation of atrial flutter and/or tachycardia is feasible even in patients with multiple chronic atrial and ventricular indwelling catheters; and (2) RF applications in close proximity of defibrillator and pacing catheters does not appear to alter their function unless lesions are produced in the area surrounding the distal pacing electrode.
Limitations of Tachycardia Confirmation and Rate Classification Algorithms in a Third‐Generation Implantable Cardioverter Defibrillator
Authors: STAMBLER BRUCE S. , WOOD MARK A. , ELLENBOGEN KENNETH A.
Published: July 2006

Newer ICDs provide antitachycardia (ATP) and bradycardia pacing and cardioversion and defibrillaiion shocks based on sensed interval criteria. The objectives of this investigation were to determine the algorithm related errors in tachycardia confirmation and rate classification that occurred in patients with a third‐generation, noncommitted, tiered ICD therapy. Forty‐three consecutive patients with the Guardian ATP 4210 ICD, which uses an X out of Y sensed interval counting algorithm for tachycardia detection, confirmation, and classification were studied. Surface ECGs, intracardiac electrograms, stored data logs, and sense histories were reviewed to diagnose errors due to these algorithms that resulted in delivery of inappropriate therapy or inhibition of appropriate therapy. Sixty‐eight classification or confirmation algorithm errors from 7,610 tachycardia detections (< 1 %) were diagnosed in 23 (53%) of 43 patients. Three types of errors not related to device or sensing lead malfunction or programming mistakes were seen. In 26 episodes, the confirmation algorithm failed to detect late tachycardia reversion of nonsustained tachyarrhythmias, on the last or next to last sensed interval, and did not inhibit ATP (n = 17) or shocks (n = 9). In 28 episodes, inaccurate classification of tachycardia rate resulted in inappropriate ATP (n = 23) or shock (n = 5) therapy. In 14 episodes, the posttherapy reconfirmation algorithm produced inhibition of VVI pacing and prolonged asystole following shock therapy. These errors in tachycardia confirmation and rate classification were due to the inherent limitations of the X out of Y counting algorithm.
Verapamil Sensitive Incessant Ventricular Tachycardia in the Newborn
Authors: DHALA ANWER , LEWIS DAVID A. , GARLAND JEFFREY , PELECH ANDREW N.
Published: July 2006

Incessant VTs in infancy are often poorly tolerated. Response to conventional antiarrhythmic therapy is disappointing. The present case involves a 3‐week‐old infant with an incessant VT of a left bundle branch block, and normal axis morphology. This tachycardia was inducible with both atrial and ventricular pacing, but not by premature stimulation. Tachycardia persisted despite treatment with adenosine, esmolol, procainamide, and flecainide. Intravenous verapamil suppressed tachycardia and prevented inducibility, and no further recurrences were seen on oral verapamil. This case suggests that some incessant VTs in infancy may be due to calcium channel related afterdepolarizations or triggered activation.
Catheter Ablation of Junctional Ectopic Tachycardia by Guarded Low Dose Radiofrequency Energy Application
Authors: WU MEI‐HWAN , LIN JIUUN‐LEE , CHANG YUNG‐CHING
Published: July 2006

The prognosis of functional ectopic tachycardia has been poor. A 9‐year‐old boy with dilated cardiomyopathy and this incessant form of tachycardia underwent RF ablation. Without retrograde atrial depolarization during tachycardia, serials of low dose RF energy were applied near the His‐bundle area to find out the arrhythmogenic foci. The optimal site for ablation showed rate acceleration at low dose application and rate slowing down followed by conversion upon increasing the energy, By using this guarded low dose ablation technique, the tachycardia was eliminated without AV block. The LV function also improved.
New Integrated Sensor Pacemaker: Comparison of Rate Responses Between an Integrated Minute Ventilation and Activity Sensor and Single Sensor Modes During Exercise and Daily Activities and Nonphysiological Interference
Authors: LEUNG SUM‐KIN , LAU CHU‐PAK , TANG MAN‐OI , LEUNG ZOE
Published: July 2006

A dual sensor DDDR pacemaker (DX2 Model 7970, Medtronic Inc.) has integrated the rate response of minute ventilation (MV) and activity (ACT) sensors. False rate acceleration by the ACT (constrained upper rate) and MV (cross‐checked by ACT) is reduced. We examined the rate response profile and rate kinetics of the automatically optimized integrated sensor by comparing with the projected rate response of ACT and MV sensors alone in nine patients. After 1 month of sensor optimization using rate profile optimization (RPO), patients underwent maximal and submaximal treadmill exercises and performed activities of daily living (ADL). The integrated sensor mode gave a faster speed of rate response with a shorter delay time, time to 50% rate response and time to 90% of rate response compared to the MV sensor during hall walk (0.37 ± 0.08, 0.7 ± 0.09, 1.43 ± 0.19 vs 1.11 ± 0.1, 1.75 ± 0.14, 2.91 ± 0.17 min; P < 0.05), The average maximal sensor rates were significantly more proportional for the integrated sensor mode compared with either the ACT or MV mode. There was no significant difference in both the maximal pacing rate among the three sensor modes during maximal exercise and the rate decay during recovery. During interference studies by arm swinging (30–40 swings/min) and external tapping of the pacemakers (2 taps/s), there was only a moderate increase in pacing rate by 13 ± 9, 16 ± 5 beats/min. Hence, the new integrated sensor with the automatic rate profile optimization algorithm resulted in improved rate response profiles during submaximal exercise and ADL compared to the individual sensor response, and the sensor blending and cross‐checking algorithm made the pacemaker relatively immune to false triggering of both the ACT and MV sensors.
Comparison of Continuously Recorded Sensor and Sinus Rates During Daily Life Activities and Standardized Exercise Testing: Efficacy of Automatically Optimized Rate Adaptive Dual Sensor Pacing to Simulate Sinus Rhythm
Authors: LAU CHU‐PAK , LEUNG SUM‐KIN , GUEROLA MODESTO , CRIJNS H.J.G.M.
Published: July 2006

The normal sinus rhythm remains the gold standard to compare the rate response of a rate adaptive pacemaker. The aim of this study was to assess an automatically optimized dual sensor system by continuous comparison of the normal sinus (SR) and sensor indicated rates (SIR). Twelve patients with complete heart block (mean age 60 ± 9 years) with normal sinus rhythm received a dual sensor pacemaker driven by combined, automatically adaptive activity and QT sensors. After I month of automatic adaptation, patients performed a treadmill exercise in the VDD mode with simultaneous collection of SR and combined SIR. Thereafter the difference between SR and SIR was recorded over a 1‐month period using a software downloaded into the pacemakers, with the patients ambulatory during this period. During exercise testing, the SR and SIR were significantly correlated (r =0.96 ± 0.02, P < 0.001), and the mean difference between SR and SIR was 4.01 ± 4.47 beats/mm. The percentages of paced beats, over the 1 month ambulatory period, that exhibited a difference between SR and SIR of 8 beats/mm were 98%± 2%, 90%± 4% and 67%± 8% for low, medium, and high workloads, respectively (P < 0.05, ANOVA). whereas > 95% of SIR were within 15 beats/min of SR independent of the level of activities. Thus, an automatically programmed dual sensor gives an accurate reflection of SR during exercise. SIR was less accurate for more vigorous daily life activities, but most of the SIR were within the normal SR variation of 15 beats/min.
Evaluation of Autosensing as an Automatic Means of Maintaining a 2:1 Sensing Safety Margin in an Implanted Pacemaker
Authors: CASTRO ANTONIO , LIEBOLD ANDREAS , VINCENTE JOSÉ , DUNCAN TIM , ALLEN JOHN C. ,   AUTOSENSING INVESTIGATION TEAM
Published: July 2006

As intracardiac signal amplitudes fluctuate due to patient activity, drug intake, and other factors, it is imperative that an adequate sensing safety margin in an implanted pacemaker be used to compensate. We studied an investigational autosensing feature that automatically adjusts the device's sensitivity. Data were collected from 55 patients, with Intermedics model 292–03 or 294–03 pacemakers, upon inclusion of the study (Visit 1); 1 month postinclusion (Visit 2); 1 month, 1 day postinclusion (Visit 3); then 1 month, 2 days postinclusion (Visit 4). Atrial (N = 45) and/or ventricular (N = 54) thresholds were assessed at each visit; during Visit 2, myopotential tests were performed at two sensitivity settings. Autosensing was activated following Visit 1, then programmed on randomly at Visit 2 or Visit 3. From Visit 2 ‐ Visit 4, patients were monitored during daily activities (D), exercise (E), and sleep (S) with 24‐hour Holter. With Autosensing on, atrial undersensing episodes were D = 33 (p > 0.2), and S = 28 (p < 0.05); ventricular undersensing episodes were D = 6 (p > 0.5). Ventricular oversensing episodes were S = 2; atrial oversensing episodes were S = 34 (p > 0.5), D = 2, and E = 3. Comparing Autosensing adjusted sensitivity with the recommended 2:1 safety margin, 4 patients (p = 0.15) experienced atrial myopotential oversensing, and 2 patients (p = 0.15) ventricular. No unanticipated clinical events occurred. Compared with the recommended 2:1 sensing safety margin, the Autosensing feature performed equal to manual programming in preventing episodes of under/oversensing, and was better for atrial undersensing during sleep. Autosensing obviates the need for periodic reprogramming of a fixed sensitivity value.
Multisite Pacing for End‐Stage Heart Failure: Early Experience
Authors: CAZEAU SERGE , RITTER PHILIPPE , LAZARUS ARNAUD , GRAS DANIEL , BACKDACH HAYSSAM , MUNDLER OLIVIER , MUGICA JACQUES
Published: July 2006

Our objective was to improve hemodynamics by synchronous right and left site ventricular pacing in patients with severe congestive heart failure (CHF). Previous studies reported a benefit of dual chamber pacing with a short AV delay in patients with severe CHF. Other works, however, show contradictory results. Deleterious effects due to a desynchronization of right (RV) and left ventricular (LV) contractions have been suggested. This study included eight subjects with widened QRS and end‐stage heart failure despite maximal medical therapy, who refused, or were not eligible to undergo heart transplantation. Each patient underwent a baseline, invasive hemodynamic evaluation with insertion of three temporary leads to allow different pacing configurations, including RV apex and outflow tract pacing, and biventricular pacing between the RV outflow tract and LV and RV apex and LV. According to the results of this baseline study, the configuration of preexistent pacemakers was modified or new systems were implanted to allow biventricular pacing, which, in patients with sinus rhythm, was atrial triggered. Biventricular pacing increased the mean cardiac index (CI) by 25% (from a baseline of 1.83 ± 0.30 L/min per m2, P < 0.006), decreased the mean V wave by 26% (from a baseline of 36 ± 12 mmHg, P < 0.004), and decreased pulmonary capillary wedge pressure by 17% (from a baseline of 31 ± 10 mmHg, P < 0.01). Four patients died (1 preoperatively, 1 intraoperatively, 2 within 3 months, and 1 of a noncardiac cause). The four surviving patients have clinically improved from New York Heart Association Functional Class IV to Class II. In these survivors, CI decreased by 15% (P < 0.007) when multisite pacing was turned off during follow‐up. In patients with end‐stage heart failure, multisite pacing may be associated with a rapid and sustained hemodynamic improvement.
U.S. Experience with the AddVent VDD(R) Pacing System
Authors: GESSMAN LAWRENCE , WHITE MELVIN , GHALY NADER , RAMAN SIVARAMAN , DAMM DONNA , MacFIE JOANNE , TIMKO COLLEEN , FIELDS EDGAR ,   THE ADDVENT PHASE I INVESTIGATORS
Published: July 2006

The AddVent pacemaker generator and model 1328C AV single‐pass lead is a new pacemaker system capable of VDD or VDDR modes. The purpose of this study was to present the initial experience with AddVent in the United States and Canada. Between May 10, 1995 and May 3, 1996, 53 devices were implanted in 52 patients and followed for a mean of 217 (±39) days. At the predischarge, 1‐, 3‐, and 6‐month follow‐up evaluations, atrial sensing thresholds and ventricular sensing and capture thresholds were measured in the supine, sitting, and standing positions to evaluate stability of atrial sensing with respect to body posture at rest. At the 1‐month follow‐up, a treadmill exercise test was performed to evaluate atrial sensing during exercise and to evaluate two new features of the AddVent called “sensor‐mediated rate smoothing” and “preferential P wave sensing.” Atrial sensing thresholds were not significantly different (P > 0.05) among body postures for any follow‐up period or among follow‐up periods for each posture. At rest, the percentage of appropriately tracked P waves observed was > 99% at each follow‐up period. During treadmill exercise, the percentage of appropriately tracked P waves was > 98.7%. Appropriate preferential P wave sensing and sensor‐mediated rate smoothing (VDDR mode) was observed. The AddVent pacing system provides safe and effective pacing therapy. Several features of VDDR pacing offer advantages over standard VDD pacing.
Evolution of Atrial Signals from a Single Lead VDD Pacemaker
Authors: PAPOUCHADO MARK , CRICK JONATHAN C. PITTS ,   for the AddVent EUROPEAN MULTICENTRE STUDY GROUP
Published: July 2006

The atrial sensing capabilities of a new single pass lead VDD pacing system (Pacesetter AddVent) were assessed in a prospective multicenter study of 101 implants during the period July 1994 through March 1996. The pacing lead (Pacesetter AV Plus) has a unique quadripolar 4‐in‐line connector and uses a pair of ring electrodes with an interelectrode spacing of 12 mm for atrial sensing. The mean age of the patients (51 men) was 73 years (range 19–91). Seventy‐five patients had complete heart block; the others had 2:1 AV block. Wide variations were found in signal amplitude: mean P wave amplitude, measured over four cycles in the supine position, was 2.4 ± 1.9 mV at implant, dropping to 1.9 ± 1.7 mV predischarge, and remaining constant at follow‐up but with a narrower range. Holter monitoring was undertaken in 24 patients, with a total of 550 monitored hours. Mean AV synchrony was 98.2%± 4.6% (excluding premature ventricular contractions), with 20 patients (83%) showing > 99% AV synchrony, with atrial sensing at 0.1 mV where needed. No oversensing was observed in any patient. There was a low incidence of atrial fibrillation (2%) and sinus bradycardia (0%). The findings show that the range of atrial signals, although wide initially, converges over the first year and remains adequate for reliable AV synchronous pacing.
Dual Chamber Pacing with a Single Lead System: Initial Clinical Results
Authors: REY JEAN LUC , EL GHELBAZOURI FOUAD , TRIBOUILLOY CHRISTOPHE
Published: July 2006

A new mode of biphasic pacing was used in 26 patients to assess the feasibility of atrial pacing by means of the floating atrial ring electrodes of a single lead VDD permanent pacing system. During implantation, atrial pacing was possible in 25 patients with a 1‐ms total pulse duration, a mean atrial threshold of 1.70 ± 0.60 V (range, 0.6–3.0), and a mean diaphragmatic threshold of 6.7 ± 2.5 V (range, 2.5–10.0). At 3 months, the atrial threshold had increased beyond 4.8 V in three patients. In the 22 other patients, the mean atrial threshold was 2.2 ± 0.5 V (range, 1.50–3.50) in the supine position and 2.5 ± 0.8 V (range, 1.5–4.8) in the sitting position. Stable atrial capture without diaphragmatic stimulation was achieved in 76% of patients.
Exercise Induced Sympathetic Influences Do Not Change Interatrial Conduction Times in VDD and DDD Pacing
Authors: ISMER BRUNO , VON KNORRE GEORG H. , VOSS WOLFGANG , GRILLE WERNER , KLENKE GEORG , PULYA KAMESH , KOGLEK WALTER , SUNTINGER ANTON , LUESSOW HEIDRON
Published: July 2006

Using telemetry, right atrial electrogram (RA), and marker channel of atrial sense events (MA) in combination with the left atrial electrogram (LA), recorded by a filtered bipolar esophageal lead, interatrial conduction during submaximal exercise and at rest was examined in 46 DDD pacemaker patients. The RA‐LA and MA‐LA conduction times measured in the presence of atrial sensing (VDD) as well as the conduction time SA‐LA from atrial stimulus (SA) to LA, determined during atrial pacing (DDD) were found to be individual constants independent of exercise induced sympathetic influences. Thus, having determined an optima! mechanical interval (LA‐LV)mech/opt from left atrium to ventricle by other methods, the optimal AV delay for DDD as well as for VDD operation can be calculated by the sum of the appropriate interatrial conduction time (SA‐LA, respectively MA‐LA) and the (LA‐LV)mech/opt interval. Due to the constant SA‐LA and MA‐LA, the difference between these two values (AV delay correction interval) is a constant as well, which remains unchanged during exercise. Therefore, in selecting the rate responsive AV delay, only hemodynamic and not electrophysiologica] measurements need to be considered.
Pacemaker Patient‐Triggered Event Recording: Accuracy, Utility, and Cost for the Pacemaker Follow‐Up Clinic
Authors: MACHADO CHRISTIAN , JOHNSON DELOS , THACKER JAMES R. , DUNCAN JAMES L.
Published: July 2006

Many pacemaker patients have vague symptoms following implantation. It is often difficult for the physician to ascertain if they are cardiac in origin. A new pacemaker feature has been introduced, Patient‐Triggered Event Records (PTER), to help the physician with this diagnosis. The PTEB is a continuously running event record which stores the cardiac rhythm and rate. Brief application of a magnet will transfer the record into the device's memory. The data recorded will be the 97 events prior to the magnet application and the 30 events following magnet removal. The exact state of pacing (atrial and ventricular sensing/pacing, or premature ventricular events) and the rate of the ventricular events will be graphically displayed by the programmer for all 127 events. Thus, the exact pacer and cardiac rhythm can be determined during the period of the symptomatic episode. A total of three PTER's can be stored within the device. If a fourth is recorded, it will replace the oldest record. Three pacemakers with the PTER feature were tested in vitro with five different simulated cardiac rhythms, A beat‐by‐beat comparison between the PTER and the 15 simulated test rhythms revealed a 100% accurate documentation by PTER. Sixteen pacemaker patients which have the PTER feature were monitored using a King of Hearts™ for a total of 43 symptomatic events. The PTER records produced clinically relevant information 98% of the time while the King of Hearts™ produced clinically relevant information 81 % of the time. A comparison of costs of the two different methods of monitoring these patients, was $2,432 versus $4.480 for the PTER and loop event monitor respectively. The PTER is an accurate, lower cost method for monitoring and diagnosing symptomatic pacemaker patients. The PTER can be used as the first diagnostic tool in troubleshooting patients with paroxysmal symptoms in the pacemaker clinic population.
Incidence of Perforation and Other Mechanical Complications During Dual Active Fixation
Authors: TRIGANO ALEXANDRE J. , TARAMASCO VINCENT , PAGANELLI FRANCK , GERARD RAYMOND , LÉVY SAMUEL
Published: July 2006

The intraoperative and early postoperative mechanical complications of a procedure combining an atrial screw‐in lead and a ventricular screw‐in lead insertion were prospectively evaluated. The procedure was performed in 119 consecutive patients (mean age 69 ± 8 years), at first implant in 100 patients and at reoperation in 19. Nine patients had previously undergone cardiac surgery and three underwent transvenous ventricular defibrillator implantation. The double sets of leads were introduced through 2 separate veins in 5 cases, through a single venous route in 114 cases, using a percutaneous approach in 75 cases and a venous cutdown in 49, and a guidewire procedure following the venotomy in 19. The screw was mannitol coated in 102 cases, exposed in 111, and extendable/retractable in 25. The fixation of the ventricular lead was performed at the apex in 108 cases, at the outflow tract in 11, and was followed by the fixation of the atrial lead at the appendage in 112 cases and at the lateral wall in 7 cases. The lead positioning and fixation were successful at first attempt in 103 cases and after repeated lead manipulation in 19 cases. The rotational torque could be transferred to the helix in all cases except in one patient who required a second vein puncture. Unintentional fixation in the ventricular chamber with subsequent failure to remove the lead occurred in one patient. Reoperation for lead dislodgment was required in two patients. In one patient, symptomatic pericarditis with pericardial effusion was observed 1 day after the procedure and resolved spontaneously. Dual active fixation is feasible with a low incidence of mechanical complications.
Value of Heart Rate Variability Parameters for Prediction of Serious Arrhythmic Events in Patients with Malignant Ventricular Arrhythmias
Authors: FILIPECKI ARTUR , TRUSZ‐GLUZA MARIA , SZYDLO KRZYSZTOF , GIEC LESZEK
Published: July 2006

Heart rate variability (HRV) assesses the electrical stability of the heart and can identify patients at risk of sudden cardiac death (SCD). The value of 10 HRV parameters from 24 hour ECG (in both time and frequency domain) to predict serious arrhythmic events (SAE) in a group of 56 patients with ventricular tachycardia and/or ventricular fibrillation of different etiologies not due to acute myocardial infarction was explored. Eighteen patients had low left ventricular ejection fractions (LVEF). During follow‐up (6–46 months, mean = 24) 8 SCD and 12 recurrences of malignant ventricular arrhythmias or ICD discharges were recorded. Proportional hazard analysis (Cox model) for SAE revealed that the mean of all 5 minute standard deviation of RR intervals (SD) and the amplitude of low frequency spectrum (L) were independent risk factors of SAE (P < 0.05). The best models were: SD+EF and L+EF where predictive values were high (sensitivity approximately 60%, specificity over 95%, positive predictive value over 90% and negative predictive value approximately 80%). Event‐free survival curves revealed a significantly shorter survival in patients with EF < 40%: 47% vs. 92%, SD < 43 ms; 56% vs. 92% and L < 16 ms; 56% vs. 89% (all P < 0.001) after 2 years. The subgroup with low EF and SD < 43 ms revealed a significantly shortened survival (27% vs 83% at 2 years, P < 0.01). Some HRV parameters, SD from the time and L from the frequency domain, were predictive of a fatal outcome in VT/VF patients. Combined SD +EF and L +EF values are powerful predictors of serious arrhythmic events.
Changes in Heart Rate Variability with Age
Authors: REARDON MICHAEL , MALIK MAREK
Published: July 2006

Depressed heart rate variability (HRV) after a myocardial infarction is associated with increased mortality. This is thought to be due to reduced parasympathetic activity and heightened sympathetic activity. Aging is associated with depressed HRV, but little is known of the affect of aging on parasympathetic activity. This study examined 56 healthy subjects (age range 40–102 years; 39 women). None had a history of heart disease or were on medication that would affect cardiac function. All had normal resting ECGs, normal heart size on chest X ray, and normal electrolytes. In all subjects, 24‐hour Holter recordings were performed and used to measure HRV. In particular, the study examined the affect of age on HRV triangular index, which gives an estimate of overall HRV, and on RMSSD (square root of the mean squared differences of successive normal‐to‐normal RR intervals), which gives an estimate of short‐term components of HRV and is thought to reflect the overall extent of vagal modulations of heart rates. Both these parameters were compared in patients younger and older than 70 years. Each recording lasted at least 17 hours; the majority of recordings were longer than 20 hours. There was a significant decrease in HRV triangular index with age (r =−0.4, P < 0.05) and no significant change in RMSSD with age(r =−0.08, P = NS). There was a significant difference in HRV index in those > 70 years compared with those < 70 years (38.0 ± 9.3 vs 31.0 ± 11, respectively, P <0.02). There was no significant difference in RMSSD between the two age groups (26.7 ± 8.2 ms vs 28.4 ± 11.3 ms, respectively, P = NS). Thus, the study concludes that aging reduces the global measure of HRV and may reflect reduced responsiveness of autonomic activity to external environmental stimuli with age. However, the time‐domain short‐term components of HRV are not affected by age and, therefore, the fast and presumably vagal modulations of heart rate appear to be maintained.
Heart Rate Variability: Its Association with Hemodynamic Function of the Left Ventricle in Patients with Coronary Heart Disease
Authors: SZYDLO KRZYSZTOF , TRUSZ‐GLUZA MARIA , FILIPECKI ARTUR , ORSZULAK WITOLD , DRZEWIECKI JANUSZ , GIEC LESZEK
Published: July 2006

Patients with heart failure secondary to coronary heart disease (CHD) are characterized by an imbalance of the autonomic nervous system, which can be assessed by analysis of the heart rate variability (HRV). However it is still unclear whether all patients with CHD reveal suppression of HRV and if it is related to hemodynamic function and contractile disturbances of the left ventricle. To answer these questions data from 105 consecutive patients were analyzed and compared with 17 healthy subjects. All study participants underwent 24‐hour ambulatory ECG recordings with calculation of HRV parameters and angiographic examination after collection of clinical data and other noninvasive evaluations. Time‐ (SDRR, SDANN, SD, pNN50) and frequency‐ (LF, HF) domain parameters of HRV were assessed. All ventriculographic and hemodynamic measurements were used in the analysis. Highly significant correlations were found between all HRV parameters, and left ventricular ejection fraction (LVEF) and left ventricular end‐diastolic pressure (P < 0.001). Patients with LVEF < 40% were characterized by significantly lower values of HRV and impairment or lack (LVEF < 20%) of diurnal variation of frequency‐domain measurements of HRV. Patients with segmental akinesis or dyskinesis also had lower values of HRV. The group with dyskinesis was characterized by significantly lower diurnal rhythms of LF and HF, independent of LVEF.
Heart Rate Variability in Isolated Rabbit Hearts
Authors: FREY BERNHARD , HEGER GEORG , MAYER CHRISTIAN , KIEGLER BERND , STÖHR HANS , STEURER GÜNTER
Published: July 2006

The presence of heart rate variability (HRV) in patients with cardiac denervation after heart transplantation raised our interest in HRV of isolated, denervated hearts. Hearts from seven adult white ELCO rabbits were transferred to a perfusion apparatus. All hearts were perfused in the working mode and in the Langendorff mode for 20 minutes each. HRV was analyzed in the frequency domain. A computer simulated test ECG at a constant rate of 2 Hz was used for error estimation of the system. In the isolated, denervated heart, HRV was of random, broadband fluctuations, different from the well‐characterized oscillations at specific frequencies in intact animals. Mean NN was 423 ± 51 ms in the Langendorff mode, 406 ± 33 ms in the working heart mode, and 500 ms in the test ECG. Total power was 663 ± 207 ms2, 817 ± 318 ms2, and 3.7 ms2, respectively. There was no significant difference in any measure of HRV between Langendorff and working heart modes. The data provide evidence for the presence of HRV in isolated, denervated rabbit hearts. Left atrial and ventricular filling, i.e., the working heart mode, did not alter HRV, indicating that left atrial or ventricular stretch did not influence the sinus nodal discharge rate.
Clinical Significance of Increased QT Dispersion in the 12‐Lead Standard ECG for Arrhythmia Risk Prediction in Dilated Cardiomyopathy
Authors: GRIMM WOLFRAM , STEDER ULRIKE , MENZ VOLKER , HOFFMANN JÜRGEN , GROTE FRANK , MAISCH BERNHARD
Published: July 2006

QT dispersion was determined from the 12‐lead standard ECGs from 107 patients with idiopathic dilated Cardiomyopathy (IDC) and compared to QT dispersion measurements in 100 healthy age and sex matched controls. QT dispersion, rate corrected QT dispersion and adjusted QTC dispersion were significantly greater in patients with IDC compared to controls. During a prospective follow‐up of 13 ± 7 months, arrhythmic events, defined as sustained VT, VF, or sudden death, occurred in 12 (11%) of 107 study patients with IDC. QT dispersion was increased in patients with arrhythmic events compared to patients without arrhythmic events during follow‐up (76 ± 17 vs 60 ± 26 ms; P = 0.03). Differences in QTC dispersion and adjusted QTC dispersion between patients with and without arrhythmic events, however, failed to reach statistical significance. Thus, although QT dispersion was increased in patients with IDC and arrhythmic events during follow‐up, its clinical usefulness for risk stratification appears to be very limited due to the large overlap of QT dispersion among patients with and without arrhythmic events.
Congestive Heart Failure and VVI Pacing Mode: Dynamic Behavior of the Dispersion of Ventricular Repolarization
Authors: MANOLIS ATHANASIOS G. , KATSIVAS APOSTOLOS , KOUTSOGEORGIS DIMITRIS , THEODORAKIS ANTONIOS , APOSTOLOPOULOS GEORGE , NIKOLAOU PAVLOS , LOUVROS NIKOLAOS
Published: July 2006

Dynamic Behavior of the Dispersion of Ventricular Repolarization. The aim of this study was to evaluate the circadian variation in the spatial dispersion of ventricular repolarization in continuously paced patients with congestive heart failure (CHF). Fourteen patients (10 males, 4 females, aged 65 ± 5 years) with CHF due to dilated cardiomyopathy (DCM) and an echocardiographic ejection fraction of 28%± 3% were studied. All patients underwent AV functional RF ablation and permanent pacemaker implantation for drug refractory chronic atrial fibrillation (AF). Patients were evaluated at 1 month postimplant with a three‐channel 24‐hour Holter monitor, using the three plane Frank orthogonal leads (X, Y, and Z), in VVI pacing mode at 70 beats/min. For each hour, the mean value of spike‐T interval dispersion of the first five beats was measured. The control group consisted of 20 patients without structural heart disease, but with AF and complete AV block, continuously paced in WI mode at 70 beats/min. The dispersion of the spike‐T interval had a circadian behavior in the study population, with higher values at night and lower during the daytime. During the daytime, the mean value of spike‐T interval dispersion was 39 ± 5 ms and during the nighttime it was 45 ± 7 ms (P = 0.003). Such a difference between day and night was not found in the control group (38 ± 6 ms and 40 ± 8 ms, respectively, P = NS), In the daytime period the mean value of spike‐T interval dispersion of our study population was comparable to that of the control group (P = NS), while during the nighttime it was significantly higher (P = 0.0004). In conclusion, by evaluating the dispersion of ventricular repolarization in two dimensions, space and time, a circadian variation was found in paced patients with CHF due to DCM. The increased QT dispersion in these patients during the nighttime period was attributed to different effects of vagal activity in normal and abnormal myocardial areas.