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  • Blackwell Futura Publishing, Inc.  (7)
Document type
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  • 1
    Electronic Resource
    Electronic Resource
    Atrial Evoked Response Integral for Automatic Capture Verification in Atrial Pacing (2003)
    350 Main Street , Malden , MA 02148-5018 , USA . : Blackwell Futura Publishing, Inc.
    Pacing and clinical electrophysiology 26 (2003), S. 0 
    Details
    ISSN: 1540-8159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: BORIANI, G., et al.: Atrial Evoked Response Integral for Automatic Capture Verification in Atrial Pacing. Beat-by-beat Autocapture is currently limited to operation in the ventricle with bipolar leads. The authors investigated the integral of the negative-going portion of the atrial evoked response integral (AERI) as a potential resource for verification of atrial capture. Intracardiac electrogram signals were collected from 59 patients (ages 67.8 ± 15.1 years) with bipolar, low polarization atrial leads. The signals were collected over a mean period of 6.1 months (minimum 4 days) after lead implantation. St. Jude Medical Affinity pulse generators were used to perform automatic capture threshold tests while the electrogram signals were recorded by a Model 3510 programming device. These signals were transferred to a personal computer in digital form for later analysis. The AERI was calculated at each programmable pacing voltage until capture was lost. The difference between the polarization integral at loss of capture and evoked response integral with successful capture was sufficient to justify enabling the atrial Autocapture feature in 53 of 59 patients in whom bipolar pacing and unipolar sensing was performed. The authors developed a calibration routine to identify automatically those patients in whom atrial Autocapture could be programmed On, based on the polarization integral at loss of capture, the estimated maximum polarization integral, and the AERI. Preliminary analysis indicated that the AERI is a practical resource for beat-by-beat atrial capture detection when used with low polarization leads. (PACE 2003; 26[Pt. II]:248–252)
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9592.2003.00026.x
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  • 2
    Electronic Resource
    Electronic Resource
    Combined Use of Morphology Discrimination, Sudden Onset, and Stability as Discriminating Algorithms in Single Chamber Cardioverter Defibrillators (2002)
    Oxford, UK : Blackwell Futura Publishing, Inc.
    Pacing and clinical electrophysiology 25 (2002), S. 0 
    Details
    ISSN: 1540-8159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: BORIANI, G., et al.: Combined Use of Morphology Discrimination, Sudden Onset, and Stability as Discriminating Algorithms in Single Chamber Cardioverter Defibrillators. Morphology Discrimination (MD) is a rhythm discriminator based on QRS morphology analysis that can be combined with other discriminators like Stability, with or without Sinus Interval History (SIH) and Sudden Onset. Thirty-five patients implanted with a St. Jude Medical single chamber ICD were evaluated during exercise testing, during induced AF, and during follow-up for 14 ± 5 months. At exercise testing (60 episodes detected) MD had a specificity (SP) of 96.7% and Sudden Onset a SP of 91.7%; during induced AF (25 episodes) both MD and Stability had a SP of 96.0%. The diagnostic performance on spontaneous arrhythmias was as follows: for ventricular tachycardia (126 episodes) a sensitivity (SE) of 94.4% for MD, 92.1% for Sudden Onset, 89.7% for Stability without SIH and 79.4% for Stability + SIH; for sinus tachycardia (44 episodes) a SP of 86.4% for MD, 97.7% for Sudden Onset, 2.3% for Stability and of 95.5% for Stability + SIH. For AF (165 cases) a SP of 67.9% for MD, 69.1% for Stability and 90.3% for Stability + SIH, 44.8% for Sudden Onset. Use of MD alone provided a SE of 94.4% and a SP of 71.4% for spontaneous arrhythmias and combined use of the discriminators in a “2 of 3” diagnostic logic implied a SP of 90.9% with maintenance of 96.0% of SE. In single chamber ICDs a wide range of SE/SP ratios may be obtained by use of multiple discriminators, but use of the algorithm in a 2 of 3 diagnostic logic may achieve a SP of 90.9% and a SE of 96.0%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9592.2002.01357.x
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  • 3
    Electronic Resource
    Electronic Resource
    Clinical Evaluation of Morphology Discrimination: An Algorithm for Rhythm Discrimination in Cardioverter Defibrillators (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: BORIANI, G., et al.: Clinical Evaluation of Morphology Discrimination: An Algorithm for Rhythm Discrimination in Cardioverter Defibrillators. The aim of this study was to test the new morphology discrimination diagnostic algorithm for ICDs that differentiates supraventricular tachycardias (SVTs) from VTs by analysis of ventricular depolarization complexes morphology. Twenty-five patients implanted with a St. Jude Ventritex single chamber ICD were studied during electrophysiological evaluation at pre-discharge and were followed for 7 ± 4 months. Sensitivity and specificity for VT detection and overall diagnostic accuracy of the morphology discrimination algorithm were calculated on 326 detected events. At electrophysiological evaluation, the algorithm was tested during 67 episodes of right atrial pacing, during 119 episodes of RV pacing (at basal interventricular septum and RV apex) and during 27 episodes of sustained AF: specificity was 98%, sensitivity was 66%, and diagnostic accuracy was 80%. All episodes of AF were correctly diagnosed as SVT. Exclusion of detections related to pacing at the basal interventricular septum, resulted in a specificity of 98%, a sensitivity of 85%, and a diagnostic accuracy of 93%. During follow-up, evaluation of the morphology discrimination algorithm on 113 spontaneous episodes (31 VTs, 31 AF, 7 SVTs, and 44 sinus tachycardias) exhibited a specificity of 89%, a sensitivity of 100%, and a diagnostic accuracy of 92%. In conclusion, the morphology discrimination algorithm exhibits a high specificity in discriminating VTs from SVTs, although with a corresponding reduction in sensitivity. The preliminary experience on spontaneous episodes is promising. To correct for the reduction in sensitivity, it is advisable to use this algorithm in parallel with other algorithms for rhythm discrimination (sudden onset, stability) coupled with extended high rate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9592.2001.00994.x
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  • 4
    Electronic Resource
    Electronic Resource
    Transvenous Low Energy Internal Cardioversion for Atrial Fibrillation: A Review of Clinical Applications and Future Developments (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: BORIANI, G., et al.: Transvenous Low Energy Internal Cardioversion for Atrial Fibrillation: A Review of Clinical Applications and Future Developments. Low energy internal atrial cardioversion can be performed by delivering biphasic shocks between transvenous catheters positioned within the cardiac chambers or great vessels. Delivery of shocks results in effective cardioversion at energies 〈 6–10 J and the procedure can be effective even when external cardioversion has failed. Shock induced discomfort varies from patient to patient, but the procedure can be usually performed without general anesthesia and eventually under mild sedation. Nevertheless, tolerability has to be improved by obtaining a substantial reduction in defibrillating thresholds. With regard to safety, delivery of shocks for defibrillating the atria implies a potential risk of inducing ventricular fibrillation; to minimize this risk, shock delivery must be synchronous to the QRS and should be avoided during rapid RR cycles (〈 300 ms). Presently, transvenous low energy cardioversion is an investigational procedure, but a widening of indications is expected in the near future. The cost of the procedure, which remains invasive and requires a brief hospital stay, must be balanced with the benefit of restoring sinus rhythm and the possibility of maintaining sinus rhythm for the medium- to long-term. Experimental and clinical investigations of low energy internal cardioversion have resulted in the development of devices for atrial defibrillation whose clinical role and cost-benefit ratio is currently under evaluation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9592.2001.00099.x
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  • 5
    Electronic Resource
    Electronic Resource
    Rhythm Discrimination by Rate Branch and QRS Morphology in Dual Chamber Implantable Cardioverter Defibrillators (2003)
    350 Main Street , Malden , MA 02148-5018 , USA . : Blackwell Futura Publishing, Inc.
    Pacing and clinical electrophysiology 26 (2003), S. 0 
    Details
    ISSN: 1540-8159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: BORIANI, G., et al.: Rhythm Discrimination by Rate Branch and QRS Morphology in Dual Chamber Implantable Cardioverter Defibrillators. Morphology Discrimination is a discriminator based on QRS morphology analysis that has been recently implemented in dual chamber implantable cardioverter defibrillators (ICDs). Detected events are initially classified according to median atrial and ventricular rates (Rate Branch). Then, a series of discriminators (Morphology Discrimination, Stability, Sudden Onset) analyze the rhythm according to specific criteria and the number of discriminators required for VT diagnosis (i.e., requiring “any” or “all” of the specific discriminators to indicate VT). The discriminating accuracy of the algorithm was evaluated in 645 detections recorded during the follow-up of 25 patients. The overall specificity for 397 supraventricular arrhythmias was 73.5% (292/397) with the tachycardia diagnosis criteria set to “any” and 90.9% (361/397) with the tachycardia diagnosis criteria set to “all.” Sensitivity for VT was 100% and 98.7% (231/234) with the tachycardia diagnosis criteria set to “any” and “all,” respectively. With the tachycardia diagnosis criteria set to “any,” specificity for atrial fibrillation was 88.6%, for atrial flutter 40.3%, for atrial tachycardia 0%, and for sinus tachycardia 97.0%. With the tachycardia diagnosis criteria set to “all,” specificity for atrial fibrillation was 92.40%, for atrial flutter 93.5%, for atrial tachycardia 54.7%, and for sinus tachycardia 99.0%. The contribution of Morphology Discrimination was crucial to improve the specificity of the Rate Branch algorithm. The implementation of Morphology Discrimination in a dual chamber ICD with Rate Branch rhythm classification allows the attainment of high specificity and high sensitivity for ventricular tachyarrhythmias. (PACE 2003; 26[Pt. II]:466–470)
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9592.2003.00073.x
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  • 6
    Electronic Resource
    Electronic Resource
    Evaluation of a Dual Chamber Implantable Cardioverter Defibrillator for the Treatment of Atrial and Ventricular Arrhythmias (2003)
    350 Main Street , Malden , MA 02148-5018 , USA . : Blackwell Futura Publishing, Inc.
    Pacing and clinical electrophysiology 26 (2003), S. 0 
    Details
    ISSN: 1540-8159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: BORIANI, G., et al.: Evaluation of a Dual Chamber Implantable Cardioverter Defibrillator for the Treatment of Atrial and Ventricular Arrhythmias. Eighty-nine patients with a documented history of atrial tachyarrhythmias or fibrillation (AF) received a cardioverter defibrillator designed to selectively differentiate and treat atrial and ventricular arrhythmias. Twenty-two patients received a coronary sinus lead and, therefore, could use a separate shock vector for selective treatment of atrial tachyarrhythmias/AF. The device is designed to treat tachyarrhythmias with antitachycardia pacing (ATP) and/or shock therapy using an atrial and/or a ventricular shock vector. Patients underwent induction and shock termination of atrial or dual tachyarrhythmias (AF/VF) to verify proper device function and to measure the arrhythmia detection time with enhancements and preventive algorithms programmed On and Off, respectively. Detection time for 329 VF inductions was 2.41 ± 0.64  seconds with enhancements On and 2.29 ± 0.47 with enhancements Off (NS). At implant or predischarge, 283 AF and/or AF/VF (121 atrial and 162 atrial/ventricular fibrillation) were induced. Shock conversion efficacy was 89.8% with AF conversion energies ranging from 0.9 to 27 J. Thirteen of the 23 patients had atrial shock conversions using the separate shock vector with an average conversion energy of 1.9 ± 1.4  J . (range 0.5–5 J). During follow-up the efficacy of ATP on atrial tachyarrhythmias was 59% and the efficacy of delivered shocks on AF was 85%. This new dual chamber cardioverter defibrillator appropriately detected and classified atrial arrhythmias, and shock therapy for AF was highly effective. The detection algorithm differentiated atrial tachyarrhythmia/AF and did not delay VF detection. The separate shock vector converted induced AF with energies ranging from 0.6 to 5 J. (PACE 2003; 26[Pt. II]:461–465)
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9592.2003.00072.x
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  • 7
    Electronic Resource
    Electronic Resource
    Abnormal Cardiac Innervation in Patients with Idiopathic Ventricular Fibrillation (2003)
    350 Main Street , Malden , MA 02148-5018 , USA . : Blackwell Futura Publishing, Inc.
    Pacing and clinical electrophysiology 26 (2003), S. 0 
    Details
    ISSN: 1540-8159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: BIFFI, M., et al.: Abnormal Cardiac Innervation in Patients with Idiopathic Ventricular Fibrillation. Idiopathic ventricular fibrillation (VF) is diagnosed in up to nearly 10% of survivors of out-of-hospital cardiac arrest. The arrhythmogenic substrate is unknown. This study examined the role of cardiac innervation as a possible contributor to this arrhythmia. Eight patients with idiopathic VF were compared with eight normal subjects (controls) by [123] I metaiodobenzylguanidine SPECT (MIBG), measuring peak uptake, late uptake, and clearance of the nuclear tracer. The left ventricle was divided in 13 segments in the bull's-eye target plot. Peak and late MIBG uptake was increased in the anterolateral segments (2,3,7,8) compared to the inferoposterior and septal segments, in controls and in patients. No difference was observed between controls and patients in the inferoposterior and septal segments. In contrast, a significantly higher MIBG uptake was observed in patients compared to controls in the anterolateral segments ( 94 ± 4% vs 81 ± 11%, P 〈 0.03 for peak uptake; 94 ± 5% vs 79 ± 12%, P 〈 0.01 for late uptake). No difference was observed in MIBG clearance in any segment in either study group. Cardiac sympathetic innervation is highly heterogeneous, though predominant in anterolateral segments in normal subjects. Patients with idiopathic VF exhibit the same distribution, though have a significantly greater density of sympathetic terminals in the anterolateral segments than controls, which may promote ventricular arrhythmias. (PACE 2003; 26[Pt. II]:357–360)
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9592.2003.00049.x
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