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  • 1
    Digitale Medien
    Digitale Medien
    350 Main Street , Malden , MA 02148-5018 , USA , and 9600 Garsington Road , Oxford OX4 2DQ , UK . : Blackwell Science Inc
    Journal of cardiovascular electrophysiology 14 (2003), S. 0 
    ISSN: 1540-8167
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Introduction: Atrial arrhythmias have emerged as a topic of great interest for clinical electrophysiologists. Noninvasive imaging of electrical function in humans may be useful for computer-aided diagnosis and treatment of cardiac arrhythmias, which can be accomplished by the fusion of data from ECG mapping and magnetic resonance imaging (MRI). Methods and Results: In this study, a bidomain-theory–based surface heart model activation time (AT) imaging approach was applied to paced rhythm data from four patients. Pacing sites were the right superior pulmonary vein, left inferior pulmonary vein, left superior pulmonary vein, coronary sinus, posterior wall of right atrium, and high right atrium. For coronary sinus pacing, the AT pattern of the right atrium was compared with a CARTO map. The root mean square error between CARTO geometry (85 nodal points) and the surface model of the right atrium was 8.6 mm. The correlation coefficient of the noninvasively obtained AT map of the right atrium and the CARTO map was 0.76. All pulmonary vein pacing sites were identified. The reconstructed pacing site of right posterior atrial pacing correlates with the invasively determined pacing catheter position with a localization distance of 4 mm. Conclusion: The individual anatomic model of the atria of each patient enables accurate noninvasive AT imaging within the atria, resulting in a localization error for the pacing sites within 10 mm. Our findings may have implications for imaging of atrial activity in patients with focal arrhythmias or focal triggers. (J Cardiovasc Electrophysiol, Vol. 14, pp. 712-719, July 2003)
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1540-8167
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Global P Wave Duration on the 65-Lead ECG. Introduction: Pacing is believed to prevent atrial fibrillation by reducing atrial activation time. Exact correlation between P wave duration (PWD) on surface ECG and endocardial atrial activation time is still unexplored. Methods and Results: In 15 patients without structural heart disease (9 women, age 45 ± 14 years), single site [high right atrium (HRA), coronary sinus ostium (CSos), distal CS (CSd), high RA septum (Bachmann's bundle, BB)] and dual-site pacing (various combinations) was performed after ablation of supraventricular tachycardia. A 65-lead surface ECG was recorded simultaneously. Endocardial atrial activation time was measured off-line (stimulus – last bipolar recording), and the respective PWD was assessed using the root mean square and 65-channel summary plots. PWD during pacing from BB was significantly shorter (96 ± 12 msec) than during HRA (121 ± 15 msec), CSos (108 ± 9 msec), and CSd pacing (126 ± 14 msec; P 〈 0,01, respectively). PWD during dual-site pacing (HRA + BB, 91 ± 14 msec; HRA + CSos, 96 ± 7 msec; HRA + CSd, 90 ± 7 msec; BB + CSd, 96 ± 12 msec) was not significantly shorter than during pacing from BB. Correlation between endocardial atrial activation time and PWD was 0.83. Conclusion: PWD during single-site and dual-site atrial pacing represents endocardial atrial activation time and can be measured precisely using the 65-lead surface ECG. The fact that high septal pacing results in the shortest PWD may have implications for preventive pacing in patients with atrial fibrillation.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    350 Main Street , Malden , MA 02148-5018 , USA , and 9600 Garsington Road , Oxford OX4 2DQ , UK . : Blackwell Science Inc
    Journal of cardiovascular electrophysiology 16 (2005), S. 0 
    ISSN: 1540-8167
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Introduction: Biventricular pacing has been shown to improve the clinical status of patients with congestive heart failure, but little is known about its influence on ventricular repolarization. The aim of our study was to evaluate the effect of biventricular pacing on ECG markers of ventricular repolarization in patients with congestive heart failure. Methods and Results: Twenty-five patients with congestive heart failure, sinus rhythm (SR), and complete LBBB (6 females; age 61 ± 8 years; NYHA class II–III; echocardiographic ejection fraction 21 ± 5%; QRS ≥ 130 ms) underwent permanent biventricular DDDR pacemaker implantation. A high-resolution 65-lead body-surface ECG recording was performed at baseline and during right-, left-, and biventricular pacing, and the total 65-lead root mean square curve of the QRST complex and the interlead QT dispersion were assessed. The QRS duration was increased during right (RV)- and left ventricular (LV) pacing (127 ± 26% and 117 ± 40%; P 〈 0.05), as compared to SR (100%) and biventricular pacing (93 ± 16%; ns). The QTc interval was increased during RV and LV pacing (112 ± 12% and 114 ± 14%; P 〈 0.05) as compared to SR (100%) or biventricular pacing (99 ± 12%). There was no effect on JT interval during all pacing modes. The Tpeak-end interval was increased during right (120 ± 34%; P 〈 0.01) and LV pacing (113 ± 29%; P 〈 0.05) but decreased during biventricular pacing (81 ± 19%; P 〈 0.01). A similar effect was found for the Tpeak-end integral and the Tpeak amplitude. QT dispersion was increased during right ventricular (129 ± 16 ms; P 〈 0.05) and decreased during biventricular pacing (90 ± 12 ms; P 〈 0.01), as compared to SR (114 ± 22 ms). Conclusions: Using a high-resolution surface ECG, biventricular pacing resulted in a significant reduction of ECG markers of ventricular dispersion of repolarization.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Bradford : Emerald
    Compel 18 (1999), S. 236-249 
    ISSN: 0332-1649
    Quelle: Emerald Fulltext Archive Database 1994-2005
    Thema: Elektrotechnik, Elektronik, Nachrichtentechnik , Mathematik
    Notizen: Ventricular surface activation time maps are estimated from simulated and measured body surface potential (BSP) maps and extra-corporal magnetic field maps. In a first step the transfer matrix, relating the primary cardiac sources to the measured potential and/or magnetic field data, is calculated applying the boundary element method. Activation times are determined by minimizing a cost function which is based on this transfer matrix. This optimization method is solved by a quasi Newton method. The critical point theorem is used in order to estimate the starting column matrix.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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