Search

Background: The presence of diastolic dysfunction increases the risk of atrial fibrillation (AF), and might be associated with the left atrial (LA) substrate. The aim of the present study was to investigate the relationships between the diastolic dysfunction, atrial substrate and outcome of the catheter ablation., Methods and Results: Eighty-three patients with paroxysmal AF were enrolled. Diastolic dysfunction was defined as a left ventricular ejection fraction (LVEF) of ≥ 50%, and one of the following criteria: (1) a mitral inflow early filling velocity to atrial filling velocity ratio (E/A) of ≤ 0.75; or (2) an E/A ratio of >0.75 and a ratio of the mitral inflow early filling velocity to the velocity of the early medial mitral annular ascent of >10. Patients with diastolic dysfunction were older than those with normal cardiac function. There were no differences in the other baseline characteristics, LA diameter, or LVEF. A decreased LA voltage, and higher recurrence rate were noted in patients with diastolic dysfunction. In the univariate analysis, the patients with recurrence had a lower LA voltage and greater diastolic dysfunction. The multivariate analysis also indicated diastolic dysfunction and LA voltage as independent predictors of recurrence., Conclusions: The patients with diastolic dysfunction developed a different atrial substrate and had a worse outcome of catheter ablation for atrial fibrillation.

Previous studies have reported that increased high-sensitive C-reactive protein (hs-CRP) levels are associated with an inflammatory state. This study investigated the association among hs-CRP, substrate properties, and long-term clinical outcomes after catheter ablation of atrial fibrillation (AF). A total of 137 patients with AF (54 +/- 13 years) who underwent mapping and catheter ablation were included. The hs-CRP was measured before the first ablation procedure. The substrate properties (initiating triggers, biatrial mean voltage, and high-frequency sites) of the 2 atria and long-term outcome were investigated in patients in the low hs-CRP group (<75%, 2.92 mg/L) and high hs-CRP group (>75%, 2.92 mg/L). Patients with a higher hs-CRP were associated with an increased number of identified nonpulmonary vein ectopies (34.4% vs 17%, p = 0.034), lower mean left atrial (LA) voltage (1.72 +/- 0.73 vs 1.92 +/- 0.72 Hz, p = 0.045), and higher-frequency sites in the left atrium (71% vs 37%, p = 0.027). After a median follow-up period of 15 months, the single-procedure success rate (72% vs 53%, p = 0.008) and final success rate after multiple procedures (94% vs 81%, p = 0.02) were higher in the low hs-CRP group. In a multivariable regression model adjusted for other potential covariates, hs-CRP level (p = 0.021) and LA diameter (p = 0.032) were independent predictors of recurrence. In conclusion, baseline CRP levels before the first AF ablation procedure had an independent prognostic value in predicting long-term recurrence. Patients with a high hs-CRP level were associated with an abnormal LA substrate and high incidence of nonpulmonary vein AF sources., (Copyright 2010 Elsevier Inc. All rights reserved.)

Background: Nonpulmonary vein (PV) ectopy initiating atrial fibrillation (AF)/atrial tachycardia (AT) is not uncommon in patients with AF. The relationship of complex fractionated atrial electrograms (CFAEs) and non-PV ectopy initiating AF/AT has not been assessed. We aimed to characterize the CFAEs in the non-PV ectopy initiating AF/AT., Methods: Twenty-three patients (age 53 +/- 11 y/o, 19 males) who underwent a stepwise AF ablation with coexisting PV and non-PV ectopy initiating AF or AT were included. CFAE mapping was applied before and after the PV isolation in both atria by using a real-time NavX electroanatomic mapping system. A CFAE was defined as a fractionation interval (FI) of less than 120 ms over 8-second duration. A continuous CFAE (mostly, an FI < 50 ms) was defined as electrogram fractionation or repetitive rapid activity lasting for more than 8 seconds., Results: All patients (100%) with non-PV ectopy initiating AF or AT demonstrated corresponding continuous CFAEs at the firing foci. There was no significant difference in the FI among the PV ostial or non-PV atrial ectopy or other atrial CFAEs (54.1 +/- 5.6, 58.3 +/- 11.3, 52.8 +/- 5.8 ms, P = 0.12). Ablation targeting those continuous CFAEs terminated the AF and AT and eliminated the non-PV ectopy in all patients (100%). During a follow-up of 7 months, 22% of the patients had an AF recurrence with PV reconnections. There was no recurrence of any ablated non-PV ectopy during the follow-up., Conclusion: The sites of the origin of the non-PV ectopies were at the same location as those of the atrial continuous CFAEs. Those non-PV foci were able to initiate and sustain AF/AT. By limited ablation targeting all atrial continuous CFAEs, the AF could be effectively eliminated.

Introduction: Atrial tachycardia (AT), including focal and reentrant AT, can occur after circumferential pulmonary vein isolation (CPVI). The aim of this study was to investigate the electrophysiological characteristics of induced AT and its clinical outcome., Methods and Results: In our series of 160 patients with paroxysmal atrial fibrillation (AF), 45 ATs were induced by high-current burst pacing after CPVI in 26 patients. All induced ATs were mapped using a three-dimensional (3D) mapping system. Noninducibility was the endpoint of the ablation of the AT. Gap-related AT was considered if the AT was related to the CPVI lesions. A 16-slice multidetector computed tomography scan was performed in all patients to correlate the anatomical structure with electroanatomical mapping. Thirty-five (78%) reentrant ATs and 10 (22%) focal ATs were identified. Of those, 34 were gap-related ATs (24 reentrant and 10 focal ATs). Reentrant AT had more gaps in the left atrial appendage ridge than did focal AT (39.6% vs 0%, P = 0.02). Focal AT had a higher incidence of gap in the PV carina compared with reentrant AT (80% vs 10%, P < 0.001). Reentrant ATs were mostly terminated during the ablation creating the mitral and roof lines with crossing of the gaps. During a mean follow-up of 21 +/- 8 months, only one patient (0.6%) with induced mitral reentry had a recurrent AT., Conclusion: The location of the AT gap may be related with the complex anatomy of the LA. The induced ATs after CPVI can be eliminated by catheter ablation.

Background: Catheter ablation of the right atrial (RA) substrate has had variable efficacy in curing paroxysmal atrial fibrillation (PAF), suggesting that RA substrate ablation can play an important role in the treatment of atrial fibrillation (AF) in some patients. The aim of this study was to investigate the electrophysiological characteristics and ablation strategy and its results in a specific group of patients with paroxysmal RA-AF., Methods and Results: The study population consisted of 13 patients (8 men; age, 64+/-15 years) with drug-refractory (2+/-1 drugs), frequent episodes of PAF. Provocation maneuvers did not reveal any ectopic beat-initiating AF. However, rapid atrial pacing easily induced AF. Activation mapping during sinus rhythm, atrial pacing, and AF was visualized by using a noncontact mapping system. Noncontact mapping revealed RA reentry (6 patients with single-loop circuits and 7 with double-loop circuits) with conduction through channels between lines of block, crista terminalis gaps, and the cavotricuspid isthmus, which could be identified during sinus rhythm and atrial pacing, resulting in fibrillatory conduction in other parts of the RA. The consistency of wavefront activation was confirmed by frequency analysis from equally distributed mapping sites in the RA. Short lines of ablation lesions were aimed at the conduction channels between the lines of block, crista terminalis gaps, and the cavotricuspid isthmus, resulting in bidirectional block. AF was eliminated in 11 (85%) of 13 patients, and those 11 patients with acute success were free of AF without any antiarrhythmic drugs during the long-term follow-up period (16+/-6 months)., Conclusions: RA ablation still can cure selected patients with PAF. Linear ablation of the RA substrate guided by the electrophysiological characteristics of RA-AF is an effective approach for treating this specific group of patients with AF.

Paroxysmal atrial fibrillation (PAF) can be initiated by ectopic activation from the crista terminalis. The crista terminalis conduction gap is also a critical isthmus in atrial reentrant arrhythmias like upper and lower loop reentry. The aim of this study was to investigate the mechanism and results of catheter ablation for complex atrial arrhythmias originating from the crista terminalis using the noncontact mapping system (NCM). The study population consisted of six patients (5 men, 1 woman; 70 +/- 9 years) with drug refractory PAF and typical/atypical atrial flutter. NCM identified the earliest ectopic activation originating from the crista terminalis in these six patients. The reentry circuit of atypical atrial flutter propagated around the upper crista terminalis in five patients, and lower crista terminalis in one patient. The reentry circuit of atypical atrial flutter and the initial reentry circuit of AF conducted through the crista terminalis gap in all patients. Radiofrequency applications were delivered on the sites of ectopy, which initiated AF. Substrate modification was also performed over the crista terminalis gap (six patients) and cavotricuspid isthmus (three patients) responsible for the reentry. During a mean follow-up of 9 +/- 5 months (range 5-18 months), five patients were free of AF without antiarrhythmic drugs, and one patient did not have AF or atrial flutter using propafenone. NCM demonstrated the mechanism of crista terminalis ectopy-initiating AF and associated typical/atypical atrial flutter. Catheter ablation of crista terminalis ectopy and substrate for the reentry guided by NCM successfully eliminated these atrial arrhythmias.

LEE, P.-C., et al.: The Different Electrophysiological Characteristics in Children with Wolff-Parkinson-White Syndrome Between Those with and Without Atrial Fibrillation. Atrioventricular reciprocating tachycardia (AVRT) is known to be the most common supraventricular tachycardias in childhood. Because AF with rapid ventricular response may degenerate to ventricular fibrillation through conduction of accessory pathways (APs), it can be potentially life-threatening in some pediatric patients with WPW syndrome. However, information about WPW syndrome children associated with AF is limited. The purpose of this study was to investigate the specific electrophysiological characteristics in pediatric patients with WPW syndrome and AF. From July 1992 to February 2002, 51 pediatric patients with manifest WPW syndrome and documented AVRT underwent electrophysiological study and radiofrequency catheter ablation. In these patients, two (4%) were found to have several spontaneous episodes of AF recognized on 12-lead standard ECG or 24-hour Holter monitoring. Eleven (22%) patients had AF induced by rapid atrial pacing during the baseline procedure of electrophysiological study. The children with manifest WPW syndrome were divided into two groups: those with AF (group 1; n = 11) consisted of seven male and four female children (mean age 15 ± 3 years, range 10–18), and those without AF (group 2; n = 40) consisted of 22 boys and 18 girls (mean age 16 ± 3 years, range 7–18). The study excluded a patient who had Ebstein's anomaly associated with moderate tricuspid regurgitation and right atrial enlargement. The onset and duration of symptoms were not significantly different between the two groups. Comparing the electrophysiological characteristics, the atrial effective refractory period (ERP) was shorter in WPW syndrome children with AF (170 ± 36 vs 190 ± 38 ms, P = 0.041). This study demonstrated that the pediatric WPW syndrome patients with AF had different electrophysiological characteristics from those without AF. (PACE 2004; 27:235–239) [ABSTRACT FROM AUTHOR]

Gender differences of supraventricular tachycardias such as atrioventricular nodal re-entry, atrioventricular re-entry, and atrial fibrillation have been reported. There is little evidence of the effect of gender on focal atrial tachycardia (FAT). The study consisted of 298 patients who were referred to this institution for radiofrequency catheter ablation of FAT from October 1992 to April 2008 and included 156 men (52%) and 142 women (48%). Men were significantly older than women (57.9 ± 18.2 vs 47.2 ± 19.0 years old, p <0.001). Women had more associated arrhythmias (17.0% vs 28.9%, p = 0.01), mostly due to an increased incidence of atrioventricular nodal re-entrant tachycardia. Men had more cardiovascular co-morbidities (19.9% vs 9.9%, p = 0.02), a mechanism of increased automaticity (19.1% vs 8.1%, p = 0.01), and nonparoxysmal tachycardia (14.7% vs 4.4%, p = 0.01). No gender differences were noted among FAT number, left atrial involvement, shortest tachycardia cycle, success rate of catheter ablation, or recurrence rate of FAT. Mean duration of follow-up was 63.2 ± 47.5 months. Premenopausal women had a lesser cardiovascular co-morbidity (15.3% vs 4.3%, p = 0.04) and a greater incidence of a mechanism of increased automaticity (13.4% vs 2.9%, p = 0.03). In conclusion, gender differences in electrophysiologic characteristics were noted in FAT. [Copyright &y& Elsevier]