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  • 1
    Electronic Resource
    Electronic Resource
    Effect of the Atrial Blanking Time On the Detection of Atrial Fibrillation in Dual Chamber Pacing (2001)
    Oxford, UK : Blackwell Futura Publishing, Inc.
    Pacing and clinical electrophysiology 24 (2001), S. 0 
    Details
    ISSN: 1540-8159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: NOWAK, B., et al.: Effect of the Atrial Blanking Time On the Detection of Atrial Fibrillation in Dual Chamber Pacing. Patients with paroxysmal atrial fibrillation (PAF) and dual chamber pacemakers frequently have short postventricular atrial blanking times and sensitive atrial sensing thresholds used to provide reliable detection and mode switching during AF. However, short atrial blanking times increase the risk of atrial sensing of ventricular far-field signals. We evaluated if the length of the atrial blanking time influences the detection of AF. The study included ten patients with a VDDR (n = 7) or DDDR system (n = 3), who presented with AF at 18 follow-up visits. Bipolar atrial sensing was programmed to the most sensitive value. Atrial blanking times were programmed from 100 to 200 ms in 25-ms steps in each patient. Using marker annotation, the following parameters were measured at ten consecutive ventricular beats: VAF = the interval between ventricular stimulus and first sensing of AF; AFS = the number of atrial-sensed events between two ventricular events; and XAF = the interpolated number of atrial-sensed events during atrial blanking time. The intervals between ventricular events and between atrial-sensed event markers showed no significant differences for the five blanking times tested. There was no significant influence of the atrial blanking time onto the measured parameters (least square means ± standard error) with VAF between 281 ± 12 and 300 ± 12 ms (P = NS), AFs between 3.4 ± 0.2 and 3.6 ± 0.2 beats (P = NS) and XAF between 1.84 ± 0.12 and 2.03 ± 0.12 beats (P = NS). At ventricular rates 〈 100/min, the atrial sensing of AF in dual chamber pacemakers demonstrated no evidence for deterioration by an increase of the atrial blanking time from 100 to 200 ms. Thus, the risk of ventricular far-field sensing may be reduced without compromising atrial sensing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9592.2001.00496.x
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  • 2
    Electronic Resource
    Electronic Resource
    How Reliable is Atrial Sensing in Single-Lead VDD Pacing: Comparison of Three Systems (1998)
    Oxford, UK : Blackwell Publishing Ltd
    Pacing and clinical electrophysiology 21 (1998), S. 0 
    Details
    ISSN: 1540-8159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: This study evaluated the reliability of atrial sensing, expressed as AV synchronous stimulation, in three VDD systems with the atrial sensitivity (AS) programmed to a conventional value with a 2:1 safety margin compared to most-sensitive values. We studied 34 sex- and age-matched patients with 3 VDD systems: 14 with Unity 292–07, 10 with Saphir 600, and 10 with Thera VDD (5 model 8948 and 5 model 8968i). Two 24-hour Hollers were performed on consecutive days. The AS was programmed in a randomized order to its most-sensitive value or to a 2:1 safety margin. All other parameters were programmed identically. The patients underwent a myopotential oversensing test and a daily life activity protocol. A beat-to-beat analysis of the Holters was performed to determine AV synchrony. For the entire group AV synchrony with conventional AS was 98.63%± 2.57%, compared to 99.80%± 0.43% with most-sensitive values (p = 0.002). There was no difference between the three systems with conventional AS. With the most-sensitive AS, AV synchrony was: Unity 99.99%± 0.03%, Saphir 99.42%± 0.60% (P = 0.002), Thera 99.81 %± 0.35% (ns). In the Saphir system with an atrial blanking period of 150 ms, ventricular far-field sensing could be demonstrated in 5 of 10 patients. This reduced the percentage of AV synchrony due to an unwanted mode-switch to a nontracking mode. Myopotential oversensing was not detected in any patient. Conclusion: The VDD systems tested under identical conditions showed reliable P wave sensing at the most-sensitive atrial sensing setting without myopotential oversensing. Ventricular far-field sensing reduced AV synchrony and must be avoided by appropriate refractory periods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1540-8159.1998.tb01157.x
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  • 3
    Electronic Resource
    Electronic Resource
    Is Atrial Sensing of Ventricular Far-Field Signals Important in Single-Lead VDD Pacing? (1998)
    Oxford, UK : Blackwell Publishing Ltd
    Pacing and clinical electrophysiology 21 (1998), S. 0 
    Details
    ISSN: 1540-8159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In single-lead VDD pacing the atrial sensitivity frequently is programmed to sensitive values. Atrial sensing of ventricular far-field signals should be reduced by differential atrial sensing. The aim of the study was to evaluate the effectiveness of this approach. Methods: The study included 10 patients with a single-lead VDD pacemaker (Thera 8948, Lead 5032). The atrial sensitivity was set to its most sensitive value of 0.18 mV and the telemetered intraatrial EGM was continuously recorded. After atrial tracked ventricular pacing, VVI pacing was performed with pacing rates from 100 to 160 beats/min in steps of 10 beats/min and up to 165 beats/min. The peak-to-peak amplitudes of P waves (P) and ventricular far-field signals (VFFS) were measured from the recordings. The ratio P/VFFS that defines the atrial signal-to-noise ratio was calculated, and the time from stimulus to maximum of the far-field signals amplitude (Tmax) was measured. Results: P measured 0.98 ± 0.76 mV. A VFFS was visible in the atrial channel in all patients with an amplitude of 0.45 ± 0.25 mV (range 0.01–1.0 mV), independent of the pacing rate. The ratio P/VFFS was 3.9 ± 4.2 (range 0.9–21.0). Tmax measured 99.4 ± 15.2 ms during sinus rhythm. A rate dependent shortening of Tmax to 92.7 ± 11.2 ms at 140 beats/min was observed (P = 0.001). At rates above 140 beats/min no further shortening occurred. Conclusion: Ventricular far-field signals are measurable in the atrial channel of VDD systems and may reach considerable amplitudes, which are not rate dependent. Although differential sensing provides favorable P waves to ventricular far-field signal ratios, refractory periods are needed to avoid far-field sensing. The rate dependent shortening of the ventricular signal can be detected in the atrial channel in VDD pacing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1540-8159.1998.tb01159.x
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  • 4
    Electronic Resource
    Electronic Resource
    Paroxysmal Atrial Fibrillation and High Degree AV Block: Use of Single-Lead VDDR Pacing with Mode Switching (1998)
    Oxford, UK : Blackwell Publishing Ltd
    Pacing and clinical electrophysiology 21 (1998), S. 0 
    Details
    ISSN: 1540-8159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Dual chamber rate responsive pacing incorporating a mode switching option is increasingly listed in patients with chronic paroxysmal atrial fibrillation and high degree AV block. Single-lead VDDR pacemakers have been rarely used for this indication. The purpose of this study was to determine thnir reliability of atrial sensing during atrial fibrillation, the percentage of at rial synchronous ventricular pacing, and the behavior of the sinus rate outside the phases of atrial fibrillation. We studied ten patients with a single-lead VDDR pacemaker implanted for this indication. Follow-up visits were performed at predischarge and after 1, 3, 6, 12. 18, and 24 months. During the mean follow-up period of 18.9 ± 6.9 months, the atrial sensing thresholds in sinus rhythm remained stable. Atrial synchronous ventricular stimulation was achieved in 68,7 ±31.2% (median 82.5%) of the whole follow-up time. All patients showed an adequate atrial rate response during sin us rhfthm. Atrial fibrillation was detected by the pacemakers in 24.0 ± 29.8% of time. In 3 of 10 patients the duration of atrial fibrillation showed a steady increase from visit to visit. The sensed amplitudes of atrial fibrillation ranged from 0.1–1.0 mV. A programmed atrial sensitivity of 0.1 mV was necessary to achieve complete sensing of atrial fibrillation. None of the patients experienced tachycardias with optimized pacemaker programming. Single-lead VDDR pacing incorporating a mode-switching option is useful in patients with high degree AV block and paroxysmal atrial fibrillation, since it provides atrial synchronous ventricular pacing in more than two-thirds of follow-up time. In a subgroup of patients, a progressive increase of the time during atrial fibrillation was demonstrated. A reliable detection of paroxysmal atrial fibrillation requires the programming of the atrial sensitivity to its most sensitive value.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1540-8159.1998.tb00012.x
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  • 5
    Electronic Resource
    Electronic Resource
    Pacemaker Therapy in Premature Children with High Degree AV Block (1998)
    Oxford, UK : Blackwell Publishing Ltd
    Pacing and clinical electrophysiology 21 (1998), S. 0 
    Details
    ISSN: 1540-8159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The smallest pacemaker pulse generator and a steroid-eluting bipolar epicardial lead were implanted in two premature children with symptomatic AV block. Stable capture threshold and high amplitude evoked response electrogram resulted in normal function of the pacemaker Autocapture algorithm, which adjusts output 0.3 V above the measured capture threshold. Autocapture hud previously been used only with endocardial leads. Longer-term observation is required.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1540-8159.1998.tb00052.x
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  • 6
    Electronic Resource
    Electronic Resource
    First Experience with an Automatic Sensing Algorithm in Single-Lead VDD Stimulation (1998)
    Oxford, UK : Blackwell Publishing Ltd
    Pacing and clinical electrophysiology 21 (1998), S. 0 
    Details
    ISSN: 1540-8159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: An “Autosensing” algorithm available in SSI(B) and DDD(R) pacemakers automatically adapts the device's sensitivity to changing intracardiac signals. The atrial sensing function of this algorithm was tested for the first time with a VDD pacing system in which large variations of the atrial signal may occur because the atrial electrodes float in the atrial blood pool. Methods: 15 patients with a VDD pacing system were studied (Unity 292–07, lead 425; Sulzer Intermedics). The atrial sensing threshold was measured, and the atrial sensitivity was programmed with a 2:1 safety margin. The autosensing algorithm and sensitivity profile were temporarily activated, and an ambulatory ECG with continuous marker annotation was recorded. All patients underwent a 30-minute daily life activities protocol. A beat-to-beat analysis of the ambulatory ECG was correlated with the changes in atrial sensitivity. Results: The algorithm changed the baseline sensitivity from 0.57 ± 0.23 mV during the test to 0.39 ± 0.20 mV after the final rest period (P 〈 0.05). During the test 12.6 ± 10.2 adaptations of the sensitivity occurred (range 0–33). In eight patients atrial undersensing occurred in 4.4%± 7.5% of the cycles (4–458 unsensed P waves]. In these patients, the algorithm continuously adjusted the sensitivity towards more sensitive values, operating 19.1 ± 18.3 changes compared with 5.4 ± 7.3 changes in patients without undersensing (P = 0.009). Oversensing did not occur. Conclusion: The autosensing algorithm effectively optimized atrial sensitivity in VDD pacing. In patients with atrial undersensing the algorithm continuously remained near the most sensitive settings, thus reacting as intended. A faster sensitivity adjustment of the system would be desirable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1540-8159.1998.tb01158.x
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  • 7
    Electronic Resource
    Electronic Resource
    .eta.2-Coordination of a tin-hydrogen bond to a transition metal. Molecular structure of (.eta.5-MeC5H4)(CO)2Mn(H)SnPh3 (1989)
    s.l. : American Chemical Society
    Journal of the American Chemical Society 111 (1989), S. 2572-2574 
    Details
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ja00189a032
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  • 8
    Electronic Resource
    Electronic Resource
    Reinfarction Related to PTCA-Induced Coronary Embolism after Successful Thrombolytic Therapy (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of interventional cardiology 2 (1989), S. 0 
    Details
    ISSN: 1540-8183
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Coronary embolism originating from residual thrombotic material is one of the complications arising during acute percutaneous transluminal coronary angioplasty (PTCA) in acute myocardial infarction. This case report describes a symptomatic embolization of the right posterolateral and right posterior descending branch during success-ful PTCA of a subtotal stenosis of the midright coronary artery after acute inferior myocardial infarction. Typical ECG signs of reinfarction were recorded. We succeeded in recanalizing these branches by superselective thrombolysis and angioplasty.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1540-8183.1989.tb00762.x
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  • 9
    Electronic Resource
    Electronic Resource
    Comparison of Arterial and Venous Blood Flow Between Patients with Pressure Dressing or a New Hemostatic Puncture Closure Device After Cardiac Catheterization (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of interventional cardiology 10 (1997), S. 0 
    Details
    ISSN: 1540-8183
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The aim of the study was to compare arterial and venous flow volume in the punctured leg in patients given a conventional pressure dressing and those given a new hemostatic puncture closure device (Angio-Seal) after cardiac catheterization. We prospectively measured blood flow in 25 patients with pressure dressing (group A) and 25 patients with Angio-Seal (group B) after cardiac catheterization. Duplex sonographic measurements were performed at the superficial femoral artery and vein of the punctured leg. In group A measurements were performed before catheterization, during pressure dressing, and after removal of pressure dressing. In group B we performed the measurements before catheterization and after closure of the puncture site with Angio-Seal. Mean arterial and venous blood flow of the superficial femoral artery and vein were calculated. Statistical evaluation was performed using the one-sample Wilcoxon test. In group A there was a significant reduction of blood flow volume in both the femoral artery, from a mean of 119 mL/min before puncture to 78 mL/min with pressure dressing, and the femoral vein, from 114 mL/min before puncture to 82 mL/min with pressure dressing (P 〈 0.0001). After removal of pressure dressing the blood flow rose to 119 mL/min in the femoral artery and 116 mL/min in the femoral vein. In group B there was no change in flow volume before and after catheterization (femoral artery: 117 vs 118 mL/min, femoral vein 119 vs 120 mL/min, P = ns). We conclude that the use of pressure dressing after cardiac catheterization caused a significant reduction in arterial and venous blood flow (about 30%) during immobilization. The new Angio-Seal closure device did not affect arterial or venous flow.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1540-8183.1997.tb00054.x
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  • 10
    Electronic Resource
    Electronic Resource
    Holter Recordings with Continuous Marker Annotation to Evaluate Pacemaker Function (2001)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of noninvasive electrocardiology 7 (2001), S. 0 
    Details
    ISSN: 1542-474X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background: Pacemaker marker annotations facilitate the interpretation of device behavior in addition to ECG recordings. However, they are only available in conjunction with a programmer. We studied the diagnostic value of a prototype Telemetry Holter Decoder (THD), providing continuous marker annotations on a conventional Holter.Methods: The study included 20 patients with VDD or DDDR pacemakers. A 24-hour Holter was performed using the THD. Marker annotations are transmitted from the pacemaker to the THD, which transforms them into analog signals, which are recorded on one of the Holter channels.Results: During a total recording time of 458 hours, high quality marker annotations were retrieved for every patient. Artefacts disturbed the recordings during 184 min (0.67%). The THD provided information not discernible on the ECG: intermittent atrial undersensing during sinus rhythm (1096 times). Atrial tachycardias, not visible on the ECG, were detected in 2 patients. The activation of tachycardia response algorithms was clearly annotated in 11,516 events. A total of 8875 PVC's occurred, 57.8% of which were classified incorrectly in the event counters as conducted or fusion beats. Atrial far-field sensing or VA conduction was demonstrated 4294 times. Electromagnetic interferences, not visible on the ECG, could be seen three times.Conclusion: Recording of continuous high-quality marker annotation on a conventional Holter is feasible. The THD provides important information on device behavior, even in patients assumed to have regular device function, and shows to be clearly superior to ECG interpretation alone. Such data can be used for improved programming, troubleshooting and for the validation of new algorithms. A.N.E. 2002;7(1):22–28
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1542-474X.2001.tb00135.x
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