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Atrial Fibrillation: HELP
Articles by Satoshi Higa
Based on 23 articles published since 2008
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Between 2008 and 2018, Satoshi Higa wrote the following 23 articles about Atrial Fibrillation.
 
+ Citations + Abstracts
1 Editorial Arrhythmogenic pulmonary vein myocardium in heart failure. 2011

Boukens, Bastiaan J / Baartscheer, Antonius / Higa, Satoshi. · ·Clin Exp Pharmacol Physiol · Pubmed #21781146.

ABSTRACT: -- No abstract --

2 Clinical Trial Spatiotemporal organization of the left atrial substrate after circumferential pulmonary vein isolation of atrial fibrillation. 2009

Lin, Yenn-Jiang / Tai, Ching-Tai / Kao, Tsair / Chang, Shih-Lin / Lo, Li-Wei / Tuan, Ta-Chuan / Udyavar, Ameya R / Wongcharoen, Wanwarang / Hu, Yu-Feng / Tso, Han-Wen / Tsai, Wen-Chin / Chang, Chien-Jung / Ueng, Kuo-Chang / Higa, Satoshi / Chen, Shih-Ann. ·Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan. ·Circ Arrhythm Electrophysiol · Pubmed #19808473.

ABSTRACT: BACKGROUND: There is a paucity of data regarding the mechanism of maintaining atrial fibrillation (AF) after pulmonary vein isolation (PVI) in patients with AF. The aim of this study was to examine the impact of circumferential PVI on the left atrial (LA) substrate characteristics. METHODS AND RESULTS: Seventy-two AF patients (age, 53+/-11 years) underwent mapping and catheter ablation using an NavX system. The biatrial characteristics such as the complex fractionated atrial electrograms (CFEs; based on fractionated intervals) and frequency analysis (based on dominant frequencies) were mapped before and after PVI. PVI with electric isolation was performed in all patients. In the 45 patients who did not respond to PVI, the continuous CFEs (>8 seconds, 18+/-18% and 12+/-17% of the LA sites, before and after PVI, respectively, P=0.02), degree of LA fractionation (mean fractionated interval: 75.6+/-14.3 msec versus 87.3+/-16.7 msec, P=0.001), and mean LA dominant frequencies (6.92+/-0.88 Hz versus 6.58+/-0.91 Hz, P=0.001) decreased after PVI. Complete PVI altered the distribution of the CFEs toward the LA anteroseptum, mitral annulus, and LA appendage regions. A persistent presence of continuous CFEs in the vicinity of the dominant frequencies sites (observed in 53% patients) correlated with a higher procedural AF termination rate for the CFE ablation (63% versus 23%, P<0.05). CONCLUSIONS: Complete PVI eliminated some CFEs in the LA and altered the distribution of the CFEs. The persistent presence of CFEs before and after PVI in the vicinity of the high frequency sites is important for AF maintenance after PVI.

3 Clinical Trial The impact of left atrial size on long-term outcome of catheter ablation of chronic atrial fibrillation. 2009

Lo, Li-Wei / Lin, Yenn-Jiang / Tsao, Hsuan-Ming / Chang, Shih-Lin / Udyavar, Ameya R / Hu, Yu-Feng / Ueng, Kwo-Chang / Tsai, Wen-Chin / Tuan, Ta-Chun / Chang, Chien-Jung / Tang, Wei-Hua / Higa, Satoshi / Tai, Ching-Tai / Chen, Shih-Ann. ·Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan. ·J Cardiovasc Electrophysiol · Pubmed #19602021.

ABSTRACT: BACKGROUND: The left atrial (LA) size is an important predictor of atrial fibrillation (AF) procedural termination and the long-term outcome. We sought to evaluate the long-term outcome in regard to the LA size and procedural termination. METHODS: Eighty-seven consecutive chronic AF patients (72 males, 53 +/- 10 years) underwent 3D mapping (NavX) and ablation. A stepwise approach including circumferential pulmonary vein (PV) isolation, linear ablation, and continuous complex-fractionated electrogram (CFE) ablation (targeting fractionation intervals of < 50 ms). Electrical cardioversion was applied to those without any procedural termination. The freedom from AF was defined as the maintenance of sinus rhythm without the use of any class I or III antiarrhythmic drugs after the blanking period. RESULTS: Among the 87 patients, all received a circumferential PV isolation, 93% a linear ablation, and 59% a continuous CFE ablation. Those with AF procedural termination (n = 30) had a better long-term outcome when compared with those without termination during a follow-up of 21 +/- 12 months. Moreover, a Kaplan-Meier analysis showed that in those with an LA diameter of less than 45 mm (n = 49), the freedom from AF rate was higher when procedural termination was achieved (P = 0.004). On the contrary, the outcome was comparable in those with an LA diameter of >or= 45 mm (n = 38), whether AF procedural termination occurred or not (P = 0.658). CONCLUSIONS: AF procedural termination was related to the long-term success during chronic AF ablation, especially in those with an LA diameter of less than 45 mm. The favorable effect of termination decreased when the LA diameter was >or= 45 mm.

4 Article Factor Xa inhibitors differently modulate electrical activities in pulmonary veins and the sinoatrial node. 2018

Chang, Chien-Jung / Cheng, Chen-Chuan / Chen, Yao-Chang / Higa, Satoshi / Huang, Jen-Hung / Chen, Shih-Ann / Chen, Yi-Jen. ·Division of Cardiology, Tungs' Taichung Metroharbor Hospital, Taichung, Taiwan. · Division of Cardiology, Chi-Mei Medical Center, Tainan, Taiwan; Chung Shan Medical University, Department of Internal Medicine, Taichung, Taiwan. · Department of Biomedical Engineering, and Institute of Physiology, National Defense Medical Center, Taipei, Taiwan. · Cardiac Electrophysiology and Pacing Laboratory, Division of Cardiovascular Medicine, Makiminato Central Hospital, Okinawa, Japan. · Division of Cardiovascular Medicine, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan; Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan. · Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan. · Division of Cardiovascular Medicine, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan; Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan. Electronic address: a9900112@ms15.hinet.net. ·Eur J Pharmacol · Pubmed #30017860.

ABSTRACT: Factor Xa inhibitors reduce stroke in patients with atrial fibrillation. Pulmonary veins (PVs) and the sinoatrial node (SAN) are crucial for genesis of atrial fibrillation. However, the electrophysiological effects of factor Xa inhibitors (edoxaban and rivaroxaban) on PVs and the SAN remain unclear. Conventional microelectrodes were used to record the action potential in isolated rabbit PVs and SAN preparations before and after administration of edoxaban (0.1, 0.3, and 1 μM) or rivaroxaban (0.01, 0.03, 0.1, and 0.3 μM). A whole-cell patch-clamp was used to record the late sodium current (I

5 Article Risk of Stroke in Patients With Short-Run Atrial Tachyarrhythmia. 2017

Yamada, Shinya / Lin, Chin-Yu / Chang, Shih-Lin / Chao, Tze-Fan / Lin, Yenn-Jiang / Lo, Li-Wei / Chung, Fa-Po / Hu, Yu-Feng / Tuan, Ta-Chuan / Liao, Jo-Nan / Te, Abigail Louise D / Chang, Yao-Ting / Chang, Ting-Yung / Wu, Cheng-I / Higa, Satoshi / Chen, Shih-Ann. ·From the Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taiwan (S.Y., C.-Y.L., S.-L.C., T.-F.C., Y.-J.L., L.-W.L., F.-P.C., Y.-F.H., T.-C.T., J.-N.L., A.L.D.T., Y.-T.C., T.-Y.C., C.-I.W., S.-A.C.) · Department of Cardiovascular Medicine, Fukushima Medical University, Japan (S.Y.) · Institution of Clinical Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan (S.-L.C., T.-F.C., Y.-J.L., L.-W.L., F.-P.C., Y.-F.H., T.-C.T., J.-N.L., S.-A.C.) · Department of Medicine, Taipei Veterans General Hospital, Yuan-Shan Branch, Yilan, Taiwan (C.-Y.L.) · and Cardiac Electrophysiology and Pacing Laboratory, Division of Cardiovascular Medicine, Makiminato Central Hospital, Okinawa, Japan (S.H.). ·Stroke · Pubmed #29146875.

ABSTRACT: BACKGROUND AND PURPOSE: The risk of stroke in patients with short-run atrial tachyarrhythmia (AT) remains unclear. This study aimed to investigate the relationship between short-run AT and the stroke and the use of the CHA METHODS: From the registry of 24-hour Holter monitoring, 5342 subjects without known atrial fibrillation or stroke were enrolled. Short-run AT was defined as episodes of supraventricular ectopic beats <5 seconds. RESULTS: There were 1595 subjects (29.8%) with short-run AT. During the median follow-up period of 9.0 years, 494 subjects developed new-onset stroke. Patients with short-run AT had significantly higher stroke rates compared with patients without short-run AT (11.4% versus 8.3%; CONCLUSIONS: Short-run AT increases the risk of stroke. Therefore, the CHA

6 Article Resveratrol, a red wine antioxidant, reduces atrial fibrillation susceptibility in the failing heart by PI3K/AKT/eNOS signaling pathway activation. 2015

Chong, Eric / Chang, Shih-Lin / Hsiao, Ya-Wen / Singhal, Rahul / Liu, Shuen-Hsin / Leha, Trung / Lin, Wen-Yu / Hsu, Chiao-Po / Chen, Yao-Chang / Chen, Yi-Jen / Wu, Tsu-Juey / Higa, Satoshi / Chen, Shih-Ann. ·Department of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan; Division of Cardiology, Taipei Veterans General Hospital, Taipei, Taiwan. · Division of Cardiology, Taipei Veterans General Hospital, Taipei, Taiwan. · Department of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan; Division of Cardiovascular Surgery, Taipei Veterans General Hospital, Taipei, Taiwan. · Department of Biomedical Engineering, National Defense Medical Center, Taipei, Taiwan. · Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Division of Cardiovascular Medicine, Department of Internal Medicine, Wan-Fang Hospital, Taipei Medical University, Taipei, Taiwan. · Department of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan; Division of Cardiology, Taichung Veterans General Hospital, Taichung, Taiwan. · Cardiac Electrophysiology and Pacing Laboratory, Division of Cardiovascular Medicine, Makiminato Central Hospital, Okinawa, Japan. · Department of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan; Division of Cardiology, Taipei Veterans General Hospital, Taipei, Taiwan. Electronic address: epsachen@ms41.hinet.net. ·Heart Rhythm · Pubmed #25640634.

ABSTRACT: BACKGROUND: Resveratrol has shown benefits in reducing ventricular remodeling and arrhythmias. OBJECTIVE: This study aimed to assess the therapeutic efficacy of resveratrol in reducing atrial fibrillation (AF) in a heart failure (HF) model and to explore the underlying mechanisms. METHODS: HF rabbits were created 4 weeks after undergoing coronary ligation. Group 1 (n = 6) was divided into subgroups of (a) normal rabbits, (b) HF sham rabbits, and (c) HF rabbits treated for 1 week with intraperitoneal injections of resveratrol, (d) resveratrol plus wortmannin, or (e) resveratrol plus diphenyleneiodonium chloride (DPI). All rabbits underwent epicardial catheter stimulation. Collagen content, messenger RNA and protein expression in ion channels, and phosphoinositide 3-kinase (PI3K)/AKT/endothelial nitric oxide synthase (eNOS) signaling pathways were studied in left atrial appendage (LAA) preparations. To investigate acute drug effects on left atrial electrophysiology, groups 2 a through 2e (n = 6 per group) were subjected to Langendorff perfusion. RESULTS: Higher AF inducibility was found in the HF group and groups that were given PI3K and eNOS inhibitors than in the normal and resveratrol-treated groups (P < .001). Histologic analysis of the LAA revealed a decrease in fibrosis in resveratrol-treated groups compared with the HF group (8.95% ± 1.53% vs 26.62% ± 2.19%, P < .001). In real-time polymerase chain reaction analysis, ion channels including Kv1.4, Kv1.5, KvLQT1, Kir2.1, Nav1.5, Cav1.2, NCX, SERCA2a, and phospholamban were upregulated by resveratrol. PI3K, AKT, and eNOS messenger RNA and protein expression were upregulated by resveratrol but were inhibited by the coadministration of wortmannin and DPI. CONCLUSION: Resveratrol decreases left atrial fibrosis and regulates variation in ion channels to reduce AF through the PI3K/AKT/eNOS signaling pathway.

7 Article Heat shock protein inducer modifies arrhythmogenic substrate and inhibits atrial fibrillation in the failing heart. 2013

Chang, Shih-Lin / Chen, Yao-Chang / Hsu, Chiao-Po / Kao, Yu-Hsun / Lin, Yung-Kuo / Lai, Yu-Jun / Yeh, Hung-I / Higa, Satoshi / Chen, Shih-Ann / Chen, Yi-Jen. ·Institute of Clinical Medicine and Department of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan; Division of Cardiology, Taipei Veterans General Hospital, Taipei, Taiwan. ·Int J Cardiol · Pubmed #23871620.

ABSTRACT: BACKGROUND: Geranylgeranylacetone (GGA) has been reported up-regulating heat shock protein (HSP) expression, and protecting against atrial remodeling. This study aimed to investigate the effects of GGA on atrial electrophysiology and inducibility of atrial fibrillation (AF) in heart failure (HF) model. METHODS AND RESULTS: HF rabbits were created 4 weeks after coronary artery ligation. Monophasic action potential recordings and multielectrode array were used to record the electrophysiological characteristics of left atrium (LA) in normal, or HF rabbits with (HF-GGA) and without (HF-control) oral administration of GGA (200 mg/kg, 24 h before experiments). The mRNA and protein expressions of ionic channels were measured by Western blot and PCR. HF-GGA LA (n = 10), similar to normal LA (n = 10) had a shorter action potential duration (APD) and effective refractory period than HF-control LA (n = 10). HF-GGA LA had less triggered activity and APD alternans (20% vs. 100%, P = 0.001), lower maxima slope of restitution curve of APD (0.94 ± 0.04 vs.1.69 ± 0.04, P < 0.001), and less inducibility of AF (50% vs. 100%, P = 0.033) than HF-control LA. HF-GGA LA had a shorter activation time and higher conduction velocity than HF-control LA. HF-GGA LA had a higher mRNA expression of Cav1.2, Nav1.5, Kir2.1, Kv1.4, Kv7.1, Kv11.1, sarcoplasmic reticulum Ca(2+)-ATPase, and higher phosphorylation of phospholamban than HF-control LA. CONCLUSIONS: GGA decreases triggered activity, dispersion of APD and inducibility of AF in failing heart through induction of HSP, and modulation of ionic channels and calcium homeostasis.

8 Article Different patterns of atrial remodeling after catheter ablation of chronic atrial fibrillation. 2011

Lo, Li-Wei / Tsao, Hsuan-Ming / Lin, Yenn-Jiang / Chang, Shih-Lin / Hu, Yu-Feng / Tsai, Wen-Chin / Tuan, Ta-Chun / Suenari, Kazuyoshi / Huang, Shih-Yu / Tung, Nguyen-Huu / Higa, Satoshi / Tai, Ching-Tai / Ueng, Kwo-Chang / Li, Cheng-Hung / Chao, Tze-Fan / Wu, Tsu-Juey / Chen, Shih-Ann. ·Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan. ·J Cardiovasc Electrophysiol · Pubmed #20946229.

ABSTRACT: BACKGROUND: Multiple remodeling patterns have been observed after catheter ablation of atrial fibrillation (AF). OBJECTIVE: We aimed to clarify the electrical/structural properties associated with recurrences after ablation of chronic AF. METHODS: After a stepwise ablation procedure in 120 consecutive patients with persistent/long-lasting persistent AF, 36 had a recurrence of AF (Group 1/Group 2: recurrence with paroxysmal/persistent AF, n = 16/20). RESULTS: During the first procedure, the left atrial (LA) bipolar voltage did not differ between the 2 groups, and the LA volume was smaller in Group 1 than in Group 2 and it was the only factor predicting the recurrent types (P = 0.009, OR = 1.04). In the second procedure, the bipolar voltage of the global left atrium increased (1.33 ± 0.11 mV vs 1.76 ± 0.16 mV, P = 0.001) in Group 1 and decreased (1.31 ± 0.14 mV vs 0.90 ± 0.12 mV, P = 0.01) in Group 2, when compared with that of the first procedure. The LA low-voltage area (<0.5 mV) decreased in Group 1, and increased in Group 2. The LA volume (90 ± 8 cm(3) vs 72 ± 8 cm(3), P = 0.002) decreased in the second procedure in Group 1. It remained the same in Group 2. The right atrial substrates did not change between the procedures. After a follow-up of 27 ± 3 months, all patients in Group 1 and 14 patients in Group 2 remained in sinus rhythm (P = 0.02). CONCLUSION: A better outcome with reverse electrical and structural remodeling occurred after the ablation of chronic AF when the recurrence was paroxysmal AF. Progressive electrical remodeling without any structural remodeling developed in those with a recurrence involving persistent AF.

9 Article The novel electrophysiology of complex fractionated atrial electrograms: insight from noncontact unipolar electrograms. 2010

Lo, Li-Wei / Higa, Satoshi / Lin, Yenn-Jiang / Chang, Shih-Lin / Tuan, Ta-Chuan / Hu, Yu-Feng / Tsai, Wen-Chin / Tsao, Hsuan-Ming / Tai, Ching-Tai / Ishigaki, Sugako / Oyakawa, Asuka / Maeda, Minetaka / Suenari, Kazuyoshi / Chen, Shih-Ann. ·Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan. ·J Cardiovasc Electrophysiol · Pubmed #20050959.

ABSTRACT: BACKGROUND: The noncontact mapping (NCM) system possesses the merit of global endocardial recording for unipolar and activation mapping. OBJECTIVE: We aimed to evaluate the unipolar electrogram characteristics and activation pattern over the bipolar complex fractionated atrial electrogram (CFAE) sites during atrial fibrillation (AF). METHODS: Twenty patients (age 55 +/- 11 years old, 15 males) who underwent NCM and ablation of AF (paroxysmal/persistent = 13/7) were included. Both contact bipolar (32-300 Hz) and NCM virtual unipolar electrograms (0.5-300 Hz) were simultaneously recorded along with the activation pattern (total 223 sites, 11 +/- 4 sites/patient). A CFAE was defined as a mean bipolar cycle length of The bipolar repetitive and continuous fractionated CFAEs represented different activation patterns. The former was associated with an S wave predominant unipolar morphology which may represent an important focus for maintaining AF.

10 Article The disparities in the electrogram voltage measurement during atrial fibrillation and sinus rhythm. 2010

Chang, Chien-Jung / Lin, Yenn-Jiang / Higa, Satoshi / Chang, Shih-Lin / Lo, Li-Wei / Tuan, Ta-Chuan / Hu, Yu-Feng / Udyavar, Ameya R / Tang, Wei-Hua / Tsai, Wen-Chin / Huang, Shin-Yu / Tung, Nguyen-Huu / Suenari, Kazuyoshi / Tsao, Hsuan-Ming / Chen, Shih-Ann. ·Division of Cardiology, Tung's Taichung Metroharbour Hospital, Taichung, Taiwan. ·J Cardiovasc Electrophysiol · Pubmed #19909388.

ABSTRACT: INTRODUCTION: The peak electrogram voltage is a typical metric applied at each site for voltage mapping. However, the peak amplitude depends on the direction and complexity of the wavefront propagation. The root-mean-square (RMS) measure of the amplitude is a temporal integral that represents the steady-state value. The objective of this study was to investigate the disparities between the electrogram voltage during SR and AF by using 2 recording modalities: the conventional peak voltage and an RMS measurement. METHODS AND RESULTS: This study enrolled 20 patients (age = 59 +/- 13) with paroxysmal AF undergoing catheter ablation guided by Ensite array. The unipolar electrogram voltage during SR and AF (7 seconds in duration) was obtained from the same sites, and labeled by the 3-dimensional (3D) geometry. Overall 1,200 electrograms were analyzed from equally distributed mapping sites in the left atrium. A point-by-point comparison of the unipolar peak negative voltage (PNV) showed less agreement (Bland and Altman test: 10.4% outside 2 standard deviations, and intraclass correlation coefficient [ICC]= 0.64). The RMS voltage demonstrated agreement between SR and AF for all sites (BA test: 5.9% of the sites, and the ICC = 0.81). The probability of predicting a low-voltage during AF using the voltage during SR was significantly lower when using the PNV measurement compared to that when using the RMS voltage (15% vs 61%, P < 0.05). CONCLUSION: The peak electrogram unipolar voltage during AF did not represent the voltage during SR. The RMS amplitude may be an alternative metric for voltage mapping to characterize the myocardial substrate.

11 Article Characteristics of complex fractionated electrograms in nonpulmonary vein ectopy initiating atrial fibrillation/atrial tachycardia. 2009

Lo, Li-Wei / Lin, Yenn-Jiang / Tsao, Hsuan-Ming / Chang, Shih-Lin / Hu, Yu-Feng / Tsai, Wen-Chin / Tuan, Da-Chun / Chang, Chien-Jung / Lee, Pi-Chang / Tai, Ching-Tai / Tang, Wei-Hua / Suenari, Kazuyoshi / Huang, Shih-Yu / Higa, Satoshi / Chen, Shih-Ann. ·Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan. ·J Cardiovasc Electrophysiol · Pubmed #19804543.

ABSTRACT: 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.

12 Article Efficacy of additional ablation of complex fractionated atrial electrograms for catheter ablation of nonparoxysmal atrial fibrillation. 2009

Lin, Yenn-Jiang / Tai, Ching-Tai / Chang, Shih-Lin / Lo, Li-Wei / Tuan, Ta-Chuan / Wongcharoen, Wanwarang / Udyavar, Ameya R / Hu, Yu-Feng / Chang, Chien-Jung / Tsai, Wen-Chin / Kao, Tsair / Higa, Satoshi / Chen, Shih-Ann. ·Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, 201 Sec. 2 Shih-Pai Road, Taipei, Taiwan. ·J Cardiovasc Electrophysiol · Pubmed #19642225.

ABSTRACT: BACKGROUND: The efficacy of ablation of complex fractionated atrial electrograms (CFEs) in the single ablation procedure for nonparoxysmal atrial fibrillation (AF) patients is not well demonstrated. The aim of this study was to compare the ablation strategies of pulmonary vein isolation (PVI) plus linear ablation with and without additional ablation ofCFEs in these patients. METHODS: Consecutive 60 patients (49 +/- 11 years old, 50 male, 10 female) with nonparoxysmal AF underwent catheter ablation guided by a NavX mapping system. A stepwise approach included a circumferential PVI and left atrial (LA) linear ablation followed by either the additional ablation of continuous CFEs in the LA/coronary sinus (the first 30 patients) or not (the second 30 patients), detected by an automatic algorithm. RESULTS: There was no difference in the baseline characteristics between the two groups. Complete PVI eliminated some continuous CFEs and altered the distribution of CFEs. Following PVI and linear ablation,the remaining continuous CFEs were identified in 7.9 +/-10% mapping sites of the LA and CS, and were ablated successfully with a procedural AF termination rate of 53%. With a follow-up of 19 +/-11 months, a Kaplan-Meier analysis showed that the patients with additional ablation of the CFEs had a higher rate of sinus rhythm maintenance. Multivariate analysis showed the single procedure success could be predicted by the procedural AF termination and the additional ablation of continuous CFEs in the LA/CS. CONCLUSIONS: Ablation of continuous CFEs after PVI and LA linear ablation had a better long-term efficacy based on the results of single-ablation procedure.

13 Article Role of the right atrial substrate in different types of atrial arrhythmias. 2009

Lin, Yenn-Jiang / Higa, Satoshi / Tai, Ching-Tai / Chang, Shih-Lin / Lee, Kun-Tai / Lo, Li-Wei / Ishigaki, Sugako / Tuan, Ta-Chuan / Wongcharoen, Wanwarang / Hu, Yu-Feng / Hsieh, Min-Hsiung / Tsao, Hsuan-Ming / Chen, Shih-Ann. ·Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan. ·Heart Rhythm · Pubmed #19389645.

ABSTRACT: BACKGROUND: The regional distribution of the low-voltage zones (LVZs) may relate to the maintenance of atrial arrhythmias in the right atrium (RA). OBJECTIVES: The purpose of this study was to investigate the RA substrate characteristics in different types of atrial arrhythmias originating from RA and left atrium (LA). METHODS: Forty-five patients (35 men, age = 62 +/- 15 years) with RA atypical atrial flutter (n = 15, group 1), RA atrial fibrillation (AF; n = 15, no PV initiating foci, group 2), and LA AF (n = 1 5, no RA arrhythmias, group 3) referred for three-dimensional EnSite mapping were included. Voltage and activation maps were visualized. RESULTS: The mean voltage of the RA was lower in group 2, and compared with group 3, a voltage reduction during atrial pacing was evident in groups 1 and 2. The fixed LVZs (independent of the rhythm) were mostly located along the lower crista terminalis (CT). A functional extension of the LVZ was located on the CT in 84% of patients, sinus venosa in 18%, and free-wall region in 27%, forming the borders of the slow conduction isthmus for the reentrant circuits. The number of slow conduction isthmuses was 1.3 +/- 0.9, 2.2 +/- 1.0, and 0.87 +/- 0.74, for the groups 1-3 patients, respectively (P <.05). Radiofrequency ablation connecting the LVZs successfully eliminated those isthmuses. The long-term follow-up revealed that 66% of the patients remained in sinus rhythm. CONCLUSIONS: Single and multiple slow conduction isthmuses bordered by the fixed and functional LVZs were critical for the reentrant circuits in the RA. The conduction isthmuses could be identified by their substrate characteristics and ablated successfully.

14 Article Predicting factors for atrial fibrillation acute termination during catheter ablation procedures: implications for catheter ablation strategy and long-term outcome. 2009

Lo, Li-Wei / Tai, Ching-Tai / Lin, Yenn-Jiang / Chang, Shih-Lin / Udyavar, Ameya R / Hu, Yu-Feng / Ueng, Kuo-Chang / Tsai, Wen-Chin / Tuan, Ta-Chun / Chang, Chien-Jung / Kao, Tsair / Tsao, Hsuan-Ming / Wongcharoen, Wanwarang / Higa, Satoshi / Chen, Shih-Ann. ·Department of Medicine, Division of Cardiology, Taipei Veterans General Hospital, Taipei, Taiwan. ·Heart Rhythm · Pubmed #19251203.

ABSTRACT: BACKGROUND: Termination of atrial fibrillation (AF) can be achieved by catheter ablation. It has been used as one of the procedural endpoints for AF ablation. OBJECTIVE: The purpose of this study was to investigate the factors that predict AF termination and the association with long-term outcomes. METHODS: Eighty-five consecutive AF patients (33 paroxysmal, 52 nonparoxysmal) underwent three-dimensional mapping and catheter ablation. A stepwise ablation approach included circumferential pulmonary vein (PV) isolation and left atrial (LA) linear ablation, followed by LA and right atrial (RA) electrogram-based (complex fractionated atrial electrogram) ablation. Clinical and electrophysiologic characteristics were assessed to evaluate the predictors of acute AF termination. RESULTS: In univariate analysis, a diagnosis of paroxysmal AF, shorter AF history, absence of history of heart failure, smaller LA diameter, longer postablation coronary sinus cycle length, lower LA and RA mean dominant frequencies, lower RA max dominant frequency, and higher LA voltage were related to acute termination of AF during ablation. Multivariate analysis showed that smaller LA diameter and lower preablation mean RA dominant frequency were independent predictors of AF termination. Multivariate analysis also showed that larger LA diameter and the presence of RA non-PV ectopy during the index procedure could predict late recurrence during long-term (13 +/- 8 months) follow-up. CONCLUSION: LA size and RA non-PV drivers are important for acute termination of AF and for long-term success. Careful selection of patients, extensive RA mapping, and LA ablation may enhance long-term ablation efficacy.

15 Article Acute effect of circumferential pulmonary vein isolation on left atrial substrate. 2009

Udyavar, Ameya R / Huang, Sung-Hao / Chang, Shih-Lin / Lin, Yenn-Jiang / Tai, Ching-Tai / Lo, Li-Wei / Tuan, Ta-Chuan / Hu, Yu-Feng / Wongcharoen, Wanwarang / Tsao, Hsuan-Ming / Higa, Satoshi / Chen, Shih-Ann. ·Department of Medicine and Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan. ·J Cardiovasc Electrophysiol · Pubmed #19207767.

ABSTRACT: INTRODUCTION: The left atrial (LA) substrate plays an important role in the maintenance of atrial fibrillation (AF). However, little is known about the acute effect of circumferential pulmonary vein isolation (CPVI). This study was to investigate the acute change of LA activation, voltage and P wave in surface electrocardiogram (ECG) after CPVI. METHODS AND RESULTS: Electroanatomic mapping (NavX) was performed in 50 patients with AF (mean age = 54 +/- 10 years, 36 males) who underwent only CPVI. The mean peak-to-peak bipolar voltage and total activation time of LA were obtained during sinus rhythm before and immediately after CPVI. The average duration and amplitude of P waves in 12-lead ECG were also analyzed before and after CPVI. Change in the earliest LA breakthrough sites could cause decreased LA total activation time. Downward shift in the breakthrough site was inversely proportional to the proximity of the breakthrough site to the radiofrequency lesions. A shortening of P-wave duration and decrease in voltage after CPVI were observed after CPVI. Patients with recurrent AF had less voltage reduction in the atrial wall 1 cm from the circumferential PV lesions compared with those without recurrent AF (60.1 +/- 11.7% vs 74.1 +/- 6.6%, P = 0.002). Reduction of voltage < or = 64.4% in this area after CPVI is related with recurrent AF. CONCLUSION: CPVI could result in acute change of LA substrate, involving LA activation and voltage. Less reduction of voltage in the atrial wall adjacent to the circumferential PV lesions after CPVI may be associated to the recurrence of AF.

16 Article Hypertonicity increases rabbit atrium and pulmonary vein arrhythmogenesis: a potential contributor to the genesis of atrial fibrillation. 2009

Lee, Shih-Huang / Chen, Yao-Chang / Cheng, Chen-Chuan / Higa, Satoshi / Chen, Yi-Jen / Chen, Shih-Ann. ·Shin Kong Wu Ho-Su Memorial Hospital and Department of Medicine, Fu Jen Catholic University, Taipei, Taiwan. ·Clin Exp Pharmacol Physiol · Pubmed #19018800.

ABSTRACT: 1. Pulmonary veins are the most important focus for the initiation of atrial fibrillation. Diabetes mellitus may be associated with hypertonicity and increased occurrence of atrial fibrillation. 2. The purpose of the present study was to investigate whether hypertonicity alters the electrophysiological characteristics of pulmonary veins and atria to enhance the genesis of atrial fibrillation. 3. A whole-cell patch-clamp technique was used to investigate action potentials and ionic currents in rabbit isolated single pulmonary vein and atrial cardiomyocytes during immersion in isotonic and hypertonic (1.2x normal osmolality) solutions. 4. Hypertonicity increased the spontaneous beating rates of pulmonary vein cardiomyocytes from 2.3 +/- 0.3 to 3.4 +/- 0.3 Hz (n = 11; P < 0.001). Hypertonicity prolonged action potential duration to a greater extent in atrial cardiomyocytes than in pulmonary vein cardiomyocytes. Compared with atrial cardiomyocytes, hypertonicity increased the transient inward currents and Na(+)/Ca(2+) exchange currents to a greater extent in pulmonary vein cardiomyocytes, but decreased the delayed rectified potassium currents to a lesser extent. 5. Hypertonicity plays an important role in the electrical activity of pulmonary vein and atrial cardiomyocytes, which may have a potential role in the pathophysiology of atrial fibrillation.

17 Article Induced atrial tachycardia after circumferential pulmonary vein isolation of paroxysmal atrial fibrillation: electrophysiological characteristics and impact of catheter ablation on the follow-up results. 2009

Chang, Shih-Lin / Lin, Yenn-Jiang / Tai, Ching-Tai / Lo, Li-Wei / Tuan, Ta-Chuan / Udyavar, Ameya R / Hu, Yu-Feng / Chiang, Shuo-Ju / Wongcharoen, Wanwarang / Tsao, Hsuan-Ming / Ueng, Kwo-Chang / Higa, Satoshi / Lee, Pi-Chang / Chen, Shih-Ann. ·Department of Medicine and Institute of Clinical Medicine, Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan. ·J Cardiovasc Electrophysiol · Pubmed #19017332.

ABSTRACT: 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.

18 Article Fluvastatin reduces pulmonary vein spontaneous activity through nitric oxide pathway. 2009

Hu, Yu-Feng / Chen, Yao-Chang / Cheng, Chen-Chuan / Higa, Satoshi / Chen, Yi-Jen / Chen, Shih-Ann. ·Division of Cardiology and Cardiovascular Research Center, Veterans General Hospital-Taipei, Taiwan. ·J Cardiovasc Electrophysiol · Pubmed #18775044.

ABSTRACT: INTRODUCTION: Pulmonary veins (PVs) are the most important focus for the generation of atrial fibrillation. The HMG-CoA reductase inhibitors (statins) can reduce the occurrence of atrial fibrillation. The purposes of this study were to evaluate whether statins may inhibit the PV arrhythmogenic activity to prevent atrial arrhythmias from PVs and to investigate the link between fluvastatin, nitric oxide synthase (NOS) activity, mechanical activity, and electrical activity. METHODS: Conventional microelectrodes and Western blot were used to record the electrical activity, diastolic tension, contractility and expression of Akt, endothelial nitric oxide synthase (eNOS), neuronal nitric oxide synthase (nNOS), and phosphorylated Akt and eNOS before and after the administration of fluvastatin in rabbit PVs or atria. RESULTS: Fluvastatin decreased the PV spontaneous activity, diastolic tension, and contractility, but did not change the action potential duration or resting membrane potential. The effects of fluvastatin on the PV firing rate and diastolic tension were attenuated in the presence of L-NAME (100 microM), wortmannin (100 nM), and ODQ (3 microM). Fluvastatin (1 muM) increased the phosphorylated Akt and eNOS, but did not change the total Akt or eNOS in the PVs and atria. In contrast, fluvastatin (1 microM) decreased the total nNOS in the PVs and atria. CONCLUSIONS AND IMPLICATIONS: Fluvastatin produced nitric oxide through the PI3kinase/Akt pathway, thus reducing the PV vascular diastolic tension and PV spontaneous activity. These results may contribute to the beneficial effects of statins.

19 Article Characteristics of the cavotricuspid isthmus in predicting recurrent conduction in the long-term follow-up. 2009

Lo, Li-Wei / Tai, Ching-Tai / Lin, Yenn-Jiang / Chang, Shih-Lin / Wongcharoen, Wanwarang / Tuan, Ta-Chuan / Udyavar, Ameya R / Hu, Yu-Feng / Ueng, Kuo-Chang / Tsai, Wen-Chin / Chang, Chien-Jung / Tsao, Hsuan-Ming / Higa, Satoshi / Chen, Shih-Ann. ·Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan. ·J Cardiovasc Electrophysiol · Pubmed #18691234.

ABSTRACT: BACKGROUND: The characteristics of cavotricuspid isthmus (CTI) in patients with atrial fibrillation (AF) and flutter that may predict recurrence of flutter is not known. We aimed to investigate the CTI characteristics in patients who underwent a second ablation procedure for recurrent AF after previous combined pulmonary vein (PV) and CTI ablation. METHODS: Among 196 consecutive patients with drug-refractory symptomatic AF who underwent PV isolation and CTI ablation with bidirectional isthmus block, 49 patients (age 50 +/- 12 years, 43 males) had recurrent AF and received a second procedure 291 +/- 241 days after the first procedure. Right atrial angiography for the evaluation of the CTI morphology, and the biatrial contact bipolar electrograms were obtained before both procedures. RESULTS: In the second procedure, 11 (group 1) of the 49 patients demonstrated recovered CTI conduction. Compared with the patients without CTI conduction (group 2, n = 38), group 1 patients had a higher frequency of a pouch-type anatomy (82% vs 13%, P < 0.001), longer CTI (34.0 +/- 8.6 vs 25.5 +/- 7.5 mm, P = 0.01), longer ablation time, and larger number of radiofrequency applications; furthermore, the preablation bipolar voltage decreased along both the CTI and ablation line in group 2, whereas it remained similar in group 1 in the second procedure. CONCLUSIONS: A high (22%) percentage of CTIs exhibited recurrent conduction in the long-term follow-up. The CTIs with recurrent conduction had a higher incidence of a pouch and longer length compared with those without recurrent conduction.

20 Article Spectral analysis during sinus rhythm predicts an abnormal atrial substrate in patients with paroxysmal atrial fibrillation. 2008

Lin, Yenn-Jiang / Kao, Tsair / Tai, Ching-Tai / Chang, Shih-Lin / Lo, Li-Wei / Tuan, Ta-Chuan / Udyavar, Ameya R / Hu, Yu-Feng / Tso, Han-Wen / Higa, Satoshi / Chen, Shih-Ann. ·Department of Medicine, Division of Cardiology, Taipei Veterans General Hospital, Taipei, Taiwan. ·Heart Rhythm · Pubmed #18598950.

ABSTRACT: BACKGROUND: Regions of rapid and multiple deflections can be identified with high dominant frequency (DF) during sinus rhythm (SR). These areas may play a role in the perpetuation of atrial fibrillation (AF) and indicate an atrial substrate abnormality. OBJECTIVE: The purpose of this study was to investigate the atrial substrate properties of the high-frequency sites in patients with paroxysmal AF. METHODS: Forty patients (52 +/- 12 years of age) with paroxysmal AF were studied using a three-dimensional mapping system. Spectral analysis was performed on the bipolar electrograms in the left atrium (LA) during SR. Overall, 7708 electrograms were analyzed, and the DFs higher than 70 Hz were labeled as abnormal. RESULTS: The regional distribution of the high-DF sites in the LA could be divided into two types. Type 1 includes high-DF sites existing only in the pulmonary veins (PVs; n = 19, 6.6 +/- 3.4 sites/patient). Type 2 includes high-DF sites in the LA or LA plus the PVs (n = 21, 11 +/- 5.6 sites/patient). In type 1, PV isolation (PVI) could eliminate the AF with negative AF inducibility testing after the PVI in 89% of patients. In type 2, additional LA substrate modification was needed in 81% of patients because sustained AF was induced after the PVI (P<.001, compared with type 1). Multivariate analysis showed that the lower mean voltage of the LA and high-frequency sites distribution both independently predicted a positive AF inducibility after the PVI (P<.05). CONCLUSIONS: Spectral analysis during SR can detect an abnormal atrial substrate. A regional distribution of the high-DF sites predicts the efficacy of the PVI.

21 Article The important role of pulmonary vein carina ablation as an adjunct to circumferential pulmonary vein isolation. 2008

Udyavar, Ameya R / Chang, Shih-Lin / Tai, Ching-Tai / Lin, Yenn-Jiang / Lo, Li-Wei / Tuan, Ta-Chuan / Tsao, Hsuan-Ming / Hsieh, Ming-Hsiung / Hu, Yu-Feng / Chiang, Shuo-Ju / Chen, Yi-Jen / Wongcharoen, Wanwarang / Higa, Satoshi / Ueng, Kwo-Chang / Chen, Shih-Ann. ·Division of Cardiology and Cardiovascular Research Center, National Yang-Ming University, School of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan. ·J Cardiovasc Electrophysiol · Pubmed #18462326.

ABSTRACT: OBJECTIVES AND BACKGROUND: The success rate of achieving electrical isolation by circumferential pulmonary vein ablation (CPVA) varies from 32% to 88%. We carried out ablation at the pulmonary vein carina to evaluate the elimination rates of the pulmonary vein potentials (PVPs) after one round of CPVA had failed to eliminate all the PVPs in the patients with atrial fibrillation (AF). METHODS: Ninety-seven patients (75 males; mean age: 50 +/- 12 years; 15 with persistent AF and 82 with paroxysmal AF) who underwent catheter ablation were analyzed. All patients underwent one round of CPVA with PVP elimination as the endpoint. The electrophysiology tracings were then analyzed to look for the presence of any gaps that were subsequently targeted by radiofrequency ablation. The patients in whom the PVPs still persisted underwent ablation at the pulmonary vein carina and the success rate of the PVP elimination was studied. The patients were followed up for a mean duration of 12.9 +/- 8.2 months. RESULTS: One hundred ninety-four ipsilateral pulmonary veins in 97 patients were subjected to CPVA with successful elimination of the PVPs in 110 ipsilateral pulmonary veins (success rate of 56.7%). A carina ablation was carried out in the remaining 84 ipsilateral pulmonary vein pairs harboring PVPs. Elimination of the PVPs was achieved in all the remaining ipsilateral pulmonary veins after the carina ablation. CONCLUSION: Considering the limited efficacy of CPVA in eliminating the PVPs, pulmonary vein carina ablation is advisable to substantially increase the PVP elimination rate.

22 Article Frequency analysis of the fibrillatory activity from surface ECG lead V1 and intracardiac recordings: implications for mapping of AF. 2008

Hsu, Nei-Wei / Lin, Yenn-Jiang / Tai, Ching-Tai / Kao, Tsair / Chang, Shih-Lin / Wongcharoen, Wanwarang / Lo, Li-Wei / Udyavar, Ameya R / Hu, Yu-Feng / Tso, Han-Wen / Chen, Yi-Jen / Higa, Satoshi / Chen, Shih-Ann. ·Department of Medicine, Taiwan I-Lan Hospital, I-Lan, Taiwan, Republic of China. ·Europace · Pubmed #18319264.

ABSTRACT: AIMS: Fibrillatory waves observed in the surface electrograms may be a direct reflection of the electrophysiologic mechanism of the atrial fibrillation (AF). This study compared the fibrillatory waves in the surface ECG and the individual intracardiac mapping sites in different types of paroxysmal AF. METHODS AND RESULTS: Thirty patients with paroxysmal AF originating from the pulmonary veins (PVs) or superior vena cava (SVC) were enrolled. Frequency analysis was performed on the intracardiac electrograms recorded from various mapping sites in both atria sequentially with simultaneous surface electrogram recordings. The SVC-AF patients had a trend toward a higher DF in ECG lead V1 when compared with the PV-AF patients (7.35 +/- 2.09 vs. 5.89 +/- 0.79 Hz, P = 0.018). The mean dominant frequency (DF) of the LA mapping sites in the PV-AF patients was higher than that in the SVC-AF patients (7.06 +/- 0.66 vs. 6.13 +/- 0.96 Hz, P = 0.009), whereas the mean DF of the RA mapping sites was similar between the two groups (5.84 +/- 0.80 vs. 6.26 +/- 1.11 Hz, P = NS). The intra-class correlation coefficient (ICC) between the mean DF of the RA sites and V1 was higher (r = 0.21, P = 0.02) when compared with the mean DF of the LA sites (r = -0.007, P > 0.05). Furthermore, the maximal ICC was observed in the anterolateral RA free wall (r = 0.84, P < 0.001) and not the other anatomic sites of the RA and LA. CONCLUSION: The fibrillatory activity observed in ECG lead V1 correlated primarily with the activity of the anterolateral RA free wall and thus may be useful for detecting the AF source if it is close to that area.

23 Article Consistency of complex fractionated atrial electrograms during atrial fibrillation. 2008

Lin, Yenn-Jiang / Tai, Ching-Tai / Kao, Tsair / Chang, Shih-Lin / Wongcharoen, Wanwarang / Lo, Li-Wei / Tuan, Ta-Chuan / Udyavar, Ameya R / Chen, Yi-Jen / Higa, Satoshi / Ueng, Kuo-Chang / Chen, Shih-Ann. ·Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan. ·Heart Rhythm · Pubmed #18313599.

ABSTRACT: BACKGROUND: Temporal variation in complex fractionated atrial electrograms (CFAEs) exists during atrial fibrillation (AF). OBJECTIVE: This study sought to quantify the variation in CFAEs using a fractionation interval (FI) algorithm and to define the shortest optimal recording duration required to consistently characterize the magnitude of the fractionation. METHODS: Twenty-seven patients undergoing AF mapping in the left atrium were studied. The FI and frequency analysis were performed at each mapped site for recording durations of 1 to 8 seconds. The magnitude of the fractionation was quantified by the FI algorithm, which calculated the mean interval between multiple, discrete deflections during AF. The results from each duration were statistically compared with the maximal-duration recording, as a standard. The FI values were compared with the dominant frequency values obtained from the associated frequency spectra. RESULTS: The FIs obtained from recording durations between 5 and 8 seconds had a smaller variation in the FI (P < .05) and, for those sites with a FI < 50 ms, the fractionation was typically continuous. The fast-Fourier Transform spectra obtained from the CFAE sites with recording durations of >5 seconds harbored higher dominant frequency values than those with shorter recording durations (8.1 +/- 2.5 Hz vs. 6.8 +/- 0.98 Hz, P < .05). The CFAE sites with continuous fractionation were located within the pulmonary veins and their ostia in 77% of patients with paroxysmal AF, and in only 29% of patients with nonparoxysmal AF (P < .05). CONCLUSION: The assessment of fractionated electrograms requires a recording duration of > or =5 seconds at each site to obtain a consistent fractionation. Sites with the shortest FIs consistently identified sites with the fastest electrogram activity throughout the entire left atrium and pulmonary veins.