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  • 1
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Trigger Ablation in Chronic AF. Introduction: We assessed the mode of reinitiation of atrial fibrillation (AF) after cardioversion and the efficacy of ablating these foci of reinitiation in patients with chronic AF. Methods and Results: Fifteen patients, 7 with structural heart disease, underwent mapping and catheter ablation of drug-resistant AF documented to he persistent for 5 ± 4 months. In all patients, cardioversion was followed by documentation of P on T atrial ectopy and early recurrence, which allowed mapping of the reinitiating trigger or the source of ectopy. Radiofrequency (RF) ablation was performed at pulmonary vein (PV) ostia using a target temperature of 50°C and a power limit of 30 to 40 W, with the endpoint being interruption of all local muscle conduction. A total of 32 arrhythmogenic PVs and 2 atrial foci (left septum and left appendage) were identified: 1, 2, and 3 or 4 PVs in 5, 3, and 6 patients. RF applications at the ostial perimeter resulted in progressively increasing delay, followed by abolition of PV potentials in 8, but potentials persisted in 6. A single ablation session was performed in 7 patients and 8 underwent two or three sessions because of recurrence of AF; ablation was directed at the same source due to recovery of local PV potential or at a different PV. No PV stenosis was noted either acutely or at repeated follow-up angiograms. Nine patients (60%) were in stable sinus rhythm without antiarrhythmic drugs at follow-up of 11 ± 8 months. Anticoagulants were interrupted in 7 patients. Conclusion: PVs are the dominant triggers reinitiating chronic AF in this patient population. Elimination of PV potentials by ostial RF applications results in stable sinus rhythm in 60%. A larger group and longer follow-up are needed to investigate further the role of trigger ablation in curative therapy for chronic AF.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: LV Diastolic Dysfunction in Lone AF. Lone atrial fibrillation (AF) is defined by the absence of identifiable causes of AF, but its hemodynamics have not been investigated. Twenty-eight patients with lone AF were compared with 14 control patients referred for for Woff-Parkinson-White ablation. Transthoracic and transesophageal echocardiography were performed to rule out structural heart disease, followed by transseptally performed complete hemodynamic evaluation of the left heart systolic and diastolic function. There was no evidence of diastolic dysfunction according to echocardiographic criteria in AF and control patients. There was no difference in echocardiographic measurements, except for a significantly higher inferosuperior left atrial dimension seen in the four-chamber apical view in AF patients (51 ± 10 vs 40 ± 6 mm, P = 0.03). Hemodynamic evaluation showed that end-diastolic left ventricular pressure and the nadir of the left atrial Y descent were significantly higher in lone AF patients versus controls: 13 ± 5 versus 8 ± 3 mmHg (P = 0.001) and 6.7 ± 3 versus 4.6 ± 2.7 mmHg (P = 0.05). Our results demonstrated the presence of diastolic left heart dysfunction in patients with so-called lone AF.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    350 Main Street , Malden , MA 02148 , USA , and 9600 Garsington Road , Oxford OX4 2DQ , UK . : Blackwell Science Inc
    Journal of cardiovascular electrophysiology 14 (2003), S. 0 
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Introduction: Sustained atrial fibrillation (AF) is frequently encountered during pulmonary vein (PV) isolation. The aim of this study was to evaluate the feasibility and safety of PV isolation during sustained AF. Methods and Results: Thirty-seven patients (30 men, age 54 ± 10 years ) underwent Lasso-guided isolation of 87 PVs during sustained AF. Baseline PV electrogram patterns were classified into one of two types: organized, with consistent PV activation sequence; or disorganized, with constant variation of PV activation sequence. In disorganized activity, radiofrequency ablation was performed circumferentially around the Lasso while the earliest PV potential was targeted during organized activity. Complete left atrial (LA) to PV block during AF was identified by abolition or dissociation of all sharp potentials recorded within the vein. PV isolation then was verified during sinus rhythm. Baseline activation patterns of PV potential were organized in 32 PVs (37%) [more frequently in inferior veins than superior veins (53% vs 26%, P = 0.01) ] and disorganized in 55 PVs (63%). In 59 of 87 PVs, isolation was begun and completed during AF. Radiofrequency ablation organized PV activation sequence in 75% prior to isolation. LA-PV block was confirmed during sinus rhythm in 54 (92%) of 59 PVs. In 28 of 87 PVs, sinus rhythm was restored before complete LA-PV block. Complete isolation was achieved in all 87 PVs without complications. Conclusion: PV isolation can be effectively and safely performed during sustained AF, preceded in most cases by organization of PV electrogram activity. This strategy may be the preferred alternative to multiple intraprocedural cardioversions. (J Cardiovasc Electrophysiol, Vol. 14, pp. 255-260, March 2003)
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Superior Vena Cava Reentry. High-resolution mapping of a tachycardia originating from the superior vena cava (SVC) in a patient with atrial fibrillation is described. Unidirectional circuitous repetitive activation encompassing the full tachycardia cycle length was documented around a line of block within the myocardial sleeve of the SVC. Intermittent conduction to the right atrium resulted in an irregular atrial tachycardia. Evidence of electrical heterogeneity and slow conduction persisted in sinus rhythm and was exaggerated by premature stimulation but did not reproduce the activation pattern during tachycardia. All the available evidence is best compatible with circus movement reentry within the SVC, with marked slow and anisotropic conduction responsible for the restricted dimensions of the reentrant circuit. These findings may suggest a similar substrate and arrhythmia mechanism in the myocardium of the pulmonary veins.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Irrigated-Tip Catheter Ablation of PVs. Introduction: Catheter ablation of pulmonary veins (PV) for treatment of atrial fibrillation (AF) is limited by the disparate requirements of sufficient energy delivery to achieve PV isolation while avoiding PV stenosis. The aim of the present study was to evaluate the safety and efficacy of using an irrigated-tip catheter for systematic isolation of PV. Methods and Results: The study population consisted of 136 consecutive patients (109 men, mean age 52 ± 10 years) with symptomatic, drug-refractory paroxysmal (122) or persistent (14) AF. Cavotricuspid isthmus ablation and systematic radiofrequency isolation of all four PVs (guided by a circumferential mapping catheter) was performed in all patients with a protocol using an irrigated-tip catheter. PV diameter was assessed by selective angiography. The electrophysiologic endpoint of PV isolation was achieved in 100% of patients. Bidirectional cavotricuspid isthmus block was achieved in 99% of patients. Moderate PV stenosis (50% narrowing) was observed in one patient (0.7%) without clinical consequence. No other complications were observed. Reablation procedures were required in 67 patients (49%). After a mean follow-up of 8.8 ± 5.3 months, 81% of patients were free of AF clinical recurrence, including 66% not taking any antiarrhythmic drugs. Conclusion: Systematic radiofrequency ablation of PV using an irrigated-tip catheter in patients with atrial fibrillation allows complete isolation of all four PVs with a very low incidence of stenosis.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Inc
    Journal of cardiovascular electrophysiology 12 (2001), S. 0 
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Pseudo Sinus Rhythm Originating from a Pulmonary Vein. We report the case of a patient with paroxysmal atrial fibrillation in whom the background cardiac rhythm falsely mimicked sinus rhythm but actually originated from the left superior pulmonary vein. P waves during the ectopic rhythm were flat in lead I, negative in lead aVL, and without a typical “dome-and-dart” feature in precordial leads. Radiofrequency applications inside the left superior pulmonary vein eliminated both atrial fibrillation and the ectopic pacemaker.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of cardiovascular electrophysiology 10 (1999), S. 0 
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Double Potential Criteria of Isthmus Block. introduction: The efficacy and outcome of cavotricuspid isthmus ablation guided by local electrogram-based criteria of linear block were prospectively assessed. Methods and Results: In 40-consecutive patients (age 65 ± 11 years) with typical right atrial (RA) flutter (cycle length = 255 ± 31msec), radiofrequency (RF) energy was delivered at electrograms in the isthmus coinciding with the center of the ECG plateau until termination of flutter, followed by local assessment of isthmus conduction during slow rate low-lateral RA pacing. ‘Gaps’ in the ablation line were located in the form of single or fractionated potentials centered on the isoelectric intervals of adjacent double potentials and ablated. Complete linear isthmus block was defined by the achievement of a complete corridor of parallel double potentials from the right ventricle to the inferior vena cava edge. Applications of 11 ± 7 RF applications were required in all patients to achieve a complete line of double potentials separated by an isoelectric interval of 120 ± 26 msec (range 60 to 190). After 6 ± 3 RF applications, 6 (15%) patients had evidence of isthmus block using indirect RA activation sequence mapping without a complete line of double potentials. 5 ± 5 further RF applications of eliminated local conduction and achieved complete linear block without altering descending septal RA activation. Conduction recovery occurred in 20 (50%) patients—1.85 times per patient—indicated by reversed changes in local electrograms eliminated by further ablation of the recovered gaps. After discharge, two recurrences (5%) occurred during a follow-up of 16 ± 2 months. Conclusion: Double potential mapping is an effective assessment modality for local isthmus conduction. Slow conduction limited to the ablation line is observed during ablation in 15% of patients.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    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
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Introduction: Catheter ablation for atrial fibrillation (AF) is associated with prolonged fluoroscopy times. We prospectively evaluated the use of the LocaLisa three-dimensional nonfluoroscopic catheter imaging system with the aim of reducing fluoroscopy times during pulmonary vein (PV) disconnection. Methods and Results: Fifty-two patients with AF (47 men and 5 women, mean age 53 ± 9 years) underwent disconnection of all four PVs guided by a circumferential mapping catheter. The LocaLisa navigation system was used for real-time three-dimensional nonfluoroscopic imaging of the circumferential mapping catheter and ablation catheter electrodes in 26 patients. Procedural parameters were compared with those of a control group consisting of 26 patients in whom only standard fluoroscopy was used. PV disconnection was performed similarly in both groups by circumferential ablation around the ostia, with the endpoint of disconnecting left atrium to PV breakthroughs. The cumulative duration of radiofrequency (RF) energy delivery, procedural time, and fluoroscopy time required for PV disconnection were compared. Successful disconnection was achieved in all PVs, without acute complications. There was no significant difference in cumulative RF energy delivery: 34.8 ± 11.4 minutes for the nonfluoroscopic imaging group versus 38.2 ± 10.5 minutes for the control group. The fluoroscopy time required for disconnection of all four PVs was significantly lower in the LocaLisa group than in the control group: 8.4 ± 4.3 minutes versus 23.7 ± 9.7 minutes (P 〈 0.0001). There also was a significant difference in the mean time taken for PV disconnection: 46.5 ± 12.0 minutes for the nonfluoroscopic imaging group versus 66.3 ± 18.9 minutes for the control group (P 〈 0.0001). Conclusion: By allowing continuous three-dimensional monitoring of ablation and mapping catheter position and orientation, the LocaLisa nonfluoroscopic imaging system significantly reduces fluoroscopy and PV disconnection times. (J Cardiovasc Electrophysiol, Vol. 14, pp. 693–697, July 2003)
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  • 9
    Electronic Resource
    Electronic Resource
    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
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Introduction: The incidence and characteristics of dissociated arrhythmia confined to the pulmonary vein (PV) following disconnection have not been described in a large number of patients with paroxysmal atrial fibrillation. Methods and Results: This was a prospective study of 152 patients (29 female, mean age 51 ± 11 years) referred for catheter ablation of drug-refractory paroxysmal atrial fibrillation. Following ostial ablation, the rate and regularity of any dissociated venous activity was analyzed with and without isoproterenol infusion (to achieve a heart rate of 120–140 beats/min). Patients then were classified according to their venous dissociated activity. Group 1 consisted of patients in whom the dissociated PV spike had a slow rhythm 〉1,200 ms. Group 2 consisted of patients with spontaneous repetitive dissociated discharges confined in the vein with a cycle length 〈400 ms. A total of 384 PVs were ablated in 152 patients. Disappearance of all venous potentials was observed in 88% of the treated veins; at least one dissociated venous potential was observed in the remaining 12%. Group 1 activity was seen more often than group 2 (23 patients, mean cycle length 2,300 ± 1,100 ms vs 13 patients, mean cycle length 179 ± 77 ms). Dissociated PV arrhythmia was seen most often in the right superior PV (19%). Conclusion: Dissociation as the endpoint of PV disconnection was observed in 12% of PVs. Due to the capricious nature of this activity, the actual incidence is almost certainly higher. The dissociated venous rhythm usually is slow and, less commonly, is rapid and repetitive. (J Cardiovasc Electrophysiol, Vol. 14, pp. 1173-1179, November 2003)
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of cardiovascular electrophysiology 11 (2000), S. 0 
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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