Pacing and clinical electrophysiology : PACE
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Pacing Clin Electrophysiol · Oct 2005
Multicenter Study Clinical TrialClinical results of an advanced SVT detection enhancement algorithm.
Supraventricular tachycardia (SVT) has many characteristics that are similar to ventricular tachycardia (VT). This presents a significant challenge for the SVT-detection algorithms of an implantable cardioverter defibrillator (ICD). A newly developed ICD, which utilizes a Vector Timing and Correlation algorithm as well as interval-based conventional SVT discrimination algorithms (Rhythm ID), was evaluated in this study. ⋯ The Rhythm ID algorithm achieved 100% sensitivity for VT/VF, and 92% specificity for SVT. The manual and automatic Rhythm ID update algorithms successfully acquired references, and the updated references were highly accurate.
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Pacing Clin Electrophysiol · Dec 2004
Randomized Controlled Trial Multicenter Study Clinical TrialShort-term efficacy of a telephone intervention by expert nurses after an implantable cardioverter defibrillator.
The ICD is a common therapy for treatment of ventricular arrhythmias and prevention of sudden cardiac death. After ICD therapy, 50% of survivors are known to have significantly elevated anxiety, depression, anger, and fear in getting back to normal physical activities. Despite these problems, few interventions to improve adjustment have been rigorously evaluated within a clinical trial format. ⋯ The intervention group, as compared to the control group, significantly reduced mean PCA symptoms at 1 month (11.3-8.8 vs 9.7-9.3, respectively, P < 0.02), and reduced state anxiety (36.1-31.9 vs 33.1-33.0, respectively, P < 0.08), and enhanced knowledge (21.8-22.4 vs 21.4-21.7, respectively, P < 0.02) at 3 months. The intervention did not significantly impact short-term health care use. A structured telephone intervention delivered during the first 8 weeks after ICD therapy by expert cardiovascular nurses decreased ICD related physical symptoms and anxiety, and increased SCA knowledge over 3 months.
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Pacing Clin Electrophysiol · Dec 2002
Randomized Controlled Trial Multicenter Study Clinical TrialVentricular rate stabilization for the prevention of pause dependent ventricular tachyarrhythmias: results from a prospective study in 309 ICD recipients.
Reviews of stored electrograms from ICDs revealed a 5-30% incidence of short-long-short intervals preceding the onset of recurrent ventricular tachyarrhythmias. Rate stabilization by dedicated antibradycardia pacing algorithms has, therefore, been suggested to prevent onset of pause dependent tachyarrhythmias. However, the clinical efficacy of this approach has not been studied systematically. ⋯ In an extended Cox model adjusting for confounding variables, the relative risk for recurrent episodes was 0.92 during VRS On compared to Off (95% CI: 0.58-1.48; P = 0.74). During VRS Off, pause dependent onset was documented in only 36 (8%) of 427 visually analyzed episodes. There was no significant reduction in the incidence of recurrent ventricular tachyarrhythmias with VRS On compared to the Off programming in this prospective study.
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Pacing Clin Electrophysiol · Aug 2001
Randomized Controlled Trial Multicenter Study Comparative Study Clinical TrialA randomized study on the effects of pacemaker programming to a lower output on projected pulse generator longevity.
The programmability of cardiac pacemakers enables the physician at follow-up to adjust the pacing pulse under consideration of the 100% safety margin with respect to the individual pacing threshold. The purpose of reducing the output is to prolong pacemaker longevity. The aims of this prospective, randomized trial were to compare the effects of nominal output versus a lower output on projected pacemaker longevity in single and dual chamber pacemakers. ⋯ Due to the low ventricular pacing thresholds, the 2.5-V/0.4-ms setting provided, 3 months after implantation, a > or = 100% safety margin in 99% of the patients. Programming to a lower output slightly increased projected pacemaker longevity compared to the nominal 3.5-V setting. Longevity increasedfor 5% in patients with single andfor 14% in dual chamber pulse generators.
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Pacing Clin Electrophysiol · Jan 1999
Multicenter Study Clinical Trial Controlled Clinical TrialSteroid eluting high impedance pacing leads decrease short and long-term current drain: results from a multicenter clinical trial. CapSure Z investigators.
Pacemaker lead technology has changed considerably over the past decades. The widespread use of low polarization highly porous electrodes and steroid elution electrodes has resulted in low chronic pacing thresholds, as well as a decrease in the incidence of exit block. Efforts to develop pacing leads with high impedance might theoretically lead to lower lead current drain, which is a component of battery capacity. ⋯ High impedance leads are associated with lower lead current drain than standard pacing leads in the atrium and ventricle for up to 1 year. No clinically important differences in sensing characteristics was noted with the high impedance leads in the atrium or ventricle compared to standard pacing leads. High impedance leads may result in increased pulse generator longevity.