Shih-Lin Chang

National Yang Ming University, T’ai-pei, Taipei, Taiwan

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Publications (185)702.99 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Atrial fibrillation (AF) is an independent risk factor for stroke. Recent studies have demonstrated that the CHA(2)DS(2)-VASc scheme is useful for selecting patients who are truly at low risk. The goal of the present study was to compare the risk of ischemic stroke among AF patients with a CHA(2)DS(2)-VASc score of 0 (male) or 1 (female) with those without AF. The study enrolled 509 males (CHA(2)DS(2)-VASc score=0) and 320 females (CHA(2)DS(2)-VASc score=1) with AF who did not receive any antithrombotic therapy. Patients were selected from the National Health Insurance Research Database in Taiwan. For each study patient, 10 age-matched and sex-matched subjects without AF and without any comorbidity from the CHA(2)DS(2)-VASc scheme were selected as controls. The clinical end point was the occurrence of ischemic stroke. During a follow-up of 57.4±35.7 months, 128 patients (1.4%) experienced ischemic stroke. The event rate did not differ between groups with and without AF for male patients (1.6% vs 1.6%; P=0.920). In contrast, AF was a significant risk factor for ischemic stroke among females (hazard ratio, 7.77), with event rates of 4.4% and 0.7% for female patients with and without AF (P<0.001). AF males with a CHA(2)DS(2)-VASc score of 0 were at true low risk for stroke, which was similar to that of non-AF patients. However, AF females with a score of 1 were still at higher risk for ischemic events than non-AF patients.
    Stroke 08/2012; 43(10):2551-5. DOI:10.1161/STROKEAHA.112.667865 · 6.02 Impact Factor
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    ABSTRACT: Background- The characteristics of atrial electrograms associated with atrial fibrillation (AF) termination are controversial. We investigated the electrogram characteristics that indicate procedural AF termination during continuous complex fractionated electrogram ablation. Methods and Results- Fifty-two consecutive patients with persistent AF (47 men; aged 54±9 years), who underwent electrogram-based catheter ablation in the left atrium and coronary sinus after pulmonary vein isolation, were enrolled. The intracardiac bipolar atrial electrogram recordings were characterized by (1) fractionation interval (FI) analysis (>6 seconds), (2) kurtosis (shape of the FI histogram), and (3) skewness (asymmetry of the FI histogram). Sites showing complex, fractionated electrograms (mean FI ≤60 ms) were targeted, and AF was terminated in 20 patients (38%) after the pulmonary vein isolation. The conventional complex fractionated electrogram sites (mean ≤120 ms) in patients with AF termination exhibited higher median kurtosis (2.69 [interquartile range, 2.03-3.46] versus 2.35 [interquartile range, 1.79-2.48]; P=0.024) and higher complex fractionated electrogram-mean interval (102.7±19.8 versus 87.7±15.0; P=0.008) than patients without AF termination. Furthermore, AF termination sites had higher median kurtosis than targeted sites without AF termination (5.13 [interquartile range, 3.51-6.47] versus 4.18 [interquartile range, 2.91-5.34]; P<0.01) in patients with procedural termination. In addition, patients with AF termination had a higher sinus rhythm maintenance rate after a single procedure than patients without AF termination (log-rank test, P=0.007). Conclusions- A kurtosis analysis using the FI histogram may be a useful tool in identifying the critical substrate for persistent AF and potential responders to catheter ablation.
    Circulation Arrhythmia and Electrophysiology 07/2012; 5(5):949-956. DOI:10.1161/CIRCEP.111.967612 · 5.42 Impact Factor
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    ABSTRACT: The different settings of the automatic algorithm in the Carto system (Carto XP, Biosense Webster, Diamond Bar, CA, USA) used for detecting complex fractionated electrograms (CFEs) during atrial fibrillation (AF) may influence the identification of the fragmented electrograms. We aimed to evaluate the impact of the different parameters on the detection of CFEs and the efficacy of the substrate modification after pulmonary vein isolation (PVI). A total of 1,159 electrograms were analyzed from 11 consecutive patients (age = 56 ± 12 years). The effect of the different algorithm factors, such as the high-voltage thresholds (0.12, 0.25, 0.5, 20 mV), detection algorithms (average complex interval [ACI] vs interval confidence level), and recording duration (2.5 seconds vs 5 seconds), on the disparities of the CFEs was investigated. The proportion of the different grades of CFEs depended on the detection algorithm and recording duration. The high-voltage threshold would not affect the consistency of the CFEs irrespective of the different settings of the detection algorithm or recording duration. High-grade CFEs were most consistent with an ACI algorithm and recording duration of 5 seconds (Cronbach's alpha = 0.952). Ablation consisting of a PVI and high-grade CFE sites converted AF directly to sinus rhythm in eight of 11 patients or into atrial tachycardia in one of 11. The distribution and consistency of the CFE detection depended on the detection algorithm and recording duration, but not on the high-voltage threshold. Under the ACI algorithm and a recording duration of 5 seconds, high-grade CFE sites remained highest consistency.
    Pacing and Clinical Electrophysiology 07/2012; 35(8):980-9. DOI:10.1111/j.1540-8159.2012.03444.x · 1.25 Impact Factor
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    ABSTRACT: AIMS: It remains unclear as to whether regional atrial substrates of certain areas of the atrium in patients with atrial fibrillation (AF) can be related to sinoatrial node dysfunction. We investigated the relationship between the biatrial substrate characteristics and sinus node function in these patients.METHODS AND RESULTS: The study enrolled 34 patients (aged 57 ± 11 years old; 20 males) who underwent catheter ablation for symptomatic paroxysmal AF. Sinus node dysfunction was defined as having corrected sinus node recovery time longer than 550 ms. Atrial substrate analyses of both atria and atrial conductive properties were investigated in patients with (Group 1) and without sinus node dysfunction (Group 2). The mean global bipolar voltage of both atria and the atrial refractory period were similar between the two groups. Regional analysis showed that the mean bipolar voltage for patients in Group 1 was lower than in Group 2 (1.0 ± 0.3 vs. 2.1 ± 0.7 mV, P < 0.001) only in the sinus node region, while the electrophysiological properties were similar for both groups in other anatomic regions of both atria. The right atrial total activation time was significantly longer (97 ± 9 vs. 89 ± 10 ms, P = 0.023) and the conduction velocity along the crista terminalis was significantly slower (1.0 ± 0.2 vs. 1.2 ± 0.3 m/s, P = 0.019) in Group 1 patients than in Group 2 patients.CONCLUSION: In patients with AF, regional atrial remodelling near the sinus node area was associated with sinus node dysfunction.
    Europace 07/2012; 15(2). DOI:10.1093/europace/eus219 · 3.05 Impact Factor
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    ABSTRACT: BACKGROUND: Renal dysfunction is recognized as an important risk factor for thromboembolic (TE) events in patients with atrial fibrillation (AF) under medical treatment. OBJECTIVE: To investigate whether renal dysfunction is a useful predictor of TE events among patients receiving AF ablation. We also aimed to determine whether the diagnostic accuracy of the CHA(2)DS(2)-VASc score in predicting TE events could be improved by adding renal dysfunction into the scoring system. METHODS: We enrolled a total of 547 patients with AF who underwent catheter ablation. Renal dysfunction was defined as an estimated glomerular filtration rate of <60 mL/min/1.73 m(2). The clinical end point was the occurrence of TE events (ischemic stroke, transient ischemic attack, or other systemic embolisms) during follow-up after catheter ablation. RESULTS: During a follow-up of 38.9 ± 22.5 months, 16 patients (2.9%) experienced TE events. Both the CHA(2)DS(2)-VASc score and renal dysfunction were independent predictors of TE events in the multivariate analysis. Among patients with a CHA(2)DS(2)-VASc score of 0 or 1, renal dysfunction can further stratify them into 2 groups with different event rates (4.3% vs 0.3%; P = .046). A new scoring system derived by assigning 1 more point representing renal dysfunction to the CHA(2)DS(2)-VASc score could improve its predictive accuracy; the area under the receiver operating characteristic curve increased from 0.84 to 0.88 (P = .043). CONCLUSIONS: Renal dysfunction was a significant risk factor for TE events after catheter ablation of AF and may improve the diagnostic accuracy of the CHA(2)DS(2)-VASc score.
    Heart rhythm: the official journal of the Heart Rhythm Society 06/2012; 9(11). DOI:10.1016/j.hrthm.2012.06.039 · 4.92 Impact Factor
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    ABSTRACT: We report a case with dextrocardia, corrected transposition of the great arteries. He also had an atrial septum defect (ASD) with patch repair. Activation map showed a centrifugal activation from a focal origin on the systemic lower left atrial ASD patch. Ablation of the origin can terminate the atrial tachycardia. (PACE 2012; 35:e306-e308).
    Pacing and Clinical Electrophysiology 06/2012; 35(10):e306-8. DOI:10.1111/j.1540-8159.2012.03459.x · 1.25 Impact Factor
  • Circulation Journal 06/2012; 76(10):2494-5. DOI:10.1253/circj.CJ-12-0221 · 3.69 Impact Factor
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    ABSTRACT: IntroductionLone atrial fibrillation (AF) is defined as AF occurring in the absence of any other cardiovascular disease. The prognosis of patients with lone AF varies in previous studies, and the clinical and electroanatomical characteristics of lone AF are unclear. The purpose of this study was to investigate the clinical characteristics of lone AF.Methods This study included 203 patients (52±13 years old, 144 males) that underwent circumferential pulmonary vein isolation (CPVI) for paroxysmal AF. The mean voltage and total activation time of the individual atria were obtained by using a NavX mapping system and were compared for patients with lone and non-lone AF. Several parameters, including the age, gender, AF duration, and left atrial (LA) diameter were analyzed.ResultsCompared with non-lone AF patients, lone AF patients were significantly younger (49±13 years old vs. 58±11 years old, p<0.001) and had lower body-mass index (BMI, 24.60±2.96 vs. 26.07±3.29, p=0.02), lesser cholesterol level (169.06±31.41 vs. 183.63±31.12, p=0.014), smaller LA diameter (35.89±4.90 vs. 40.86±4.62, p<0.001), and higher LA bipolar voltage (2.10±0.50 vs. 1.83±0.73 mV, p<0.05). Furthermore, a dramatic voltage reduction was observed for 60-year-old patients.Conclusion Patients with lone AF have unique clinical and electroanatomical characteristics.
    Journal of Arrhythmia 06/2012; 28(3):182–186. DOI:10.1016/j.joa.2012.01.001
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    ABSTRACT: BACKGROUND: Obesity is an important risk factor for atrial fibrillation (AF) and heart failure (HF). The effects of epicardial fat on atrial electrophysiology were not clear. This study was to evaluate whether HF may modulate the effects of epicardial fat on atrial electrophysiology. METHODS: Conventional microelectrodes recording was used to record the action potential in left (LA) and right (RA) atria of healthy (control) rabbits before and after application of epicardial fat from control or HF (ventricular pacing of 360-400bpm for 4weeks) rabbits. Adipokine profiles were checked in epicardial fat of control and HF rabbits. RESULTS: The LA 90% of AP duration was prolonged by control epicardial fat (from 77±6 to 87±7ms, p<0.05, n=7), and by HF epicardial fat (from 78±3 to 98±4ms, p<0.001, n=9). However, control or HF epicardial fat did not change the AP morphology in RA. HF epicardial fat increased the contractility in LA (61±11 vs. 35±6mg, p=0.001), but not in RA. Control fat did not change the LA or RA contractility. Moreover, control and HF epicardial fat induced early and delayed afterdepolarizations in LA and RA, but only HF epicardial fat provoked spontaneous activity and burst firing in LA (n=3/9, 33.3% vs. n=0/7, 0%, n=0/9, 0%, p<0.05). Compared to control fat, HF epicardial fat, had lower resistin, C-reactive protein and serum amyloid A, but similar interluekin-6, leptin, monocyte chemotactic protein-1, adiponectin and adipsin. CONCLUSIONS: HF epicardial fat increases atrial arrhythmogenesis, which may contribute to the higher atrial arrhythmia in obesity.
    International journal of cardiology 05/2012; 167(5). DOI:10.1016/j.ijcard.2012.05.009 · 6.18 Impact Factor
  • International journal of cardiology 05/2012; 158(3):447-9. DOI:10.1016/j.ijcard.2012.04.139 · 6.18 Impact Factor
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    ABSTRACT: Modified Pulmonary Vein Isolation in AF Ablation.  Introduction: Pulmonary vein isolation (PVI) is the primary ablation therapy in patients with atrial fibrillation (AF). We hypothesized that high dominant frequency (DF) sites (AF nests during sinus rhythm [SR]) adjacent to the PV ostia are associated with the atrial substrate that maintains AF, and PVI incorporating the high-frequency AF nests may have a higher efficacy. Methods and Results: In a prospective and randomized comparison, 126 symptomatic paroxysmal AF patients that underwent PVI were enrolled. We compared the efficacy of a modified PVI (ablation line: 1.0-1.5 cm from the PV ostium with encircling the AF nests [spectral analysis with DF >70 Hz during SR, Group II]) versus the anatomy-guided conventional PVI (Group I). In Group II, the DF value along the PV ostium was lower than 70 Hz after the PVI. The primary endpoint was the freedom from symptomatic atrial arrhythmias after a single procedure. We also followed the autonomic function by a time-domain analysis of the heart rate variability. In both groups, AF nests were observed and electric isolation was successfully obtained in all patients. With a mean duration of 16 ± 6.1 months of follow-up, Group II had a higher single procedure efficacy without drugs (78.7% vs 66.1%, log-rank test: P = 0.02), and fewer repeat procedures (6.6% vs 23%; P = 0.04), as compared to Group I. Conclusion: PVI incorporating the high frequency AF nests adjacent to the PV ostia had a better single procedure efficacy.  (J Cardiovasc Electrophysiol, Vol. pp. 1-8).
    Journal of Cardiovascular Electrophysiology 05/2012; 23(11). DOI:10.1111/j.1540-8167.2012.02379.x · 2.88 Impact Factor
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    ABSTRACT: Long-Term Outcome of SVC AF Ablation. Data of the long-term clinical outcome after superior vena cava (SVC) isolation are limited. We aimed to evaluate the long-term outcome in patients with atrial fibrillation (AF) who had triggers originating from the SVC and received catheter ablation of AF. The study consisted of 68 patients (age 56 ± 12 years old, 32 males) who underwent the ablation procedure for drug-refractory, symptomatic paroxysmal AF originating from the SVC since 1999. Group 1 consisted of 37 patients with AF initiated from the SVC only, and group 2 consisted of 31 patients with both SVC and pulmonary vein (PV) triggers. During a follow-up period of 88 ± 50 months, the AF recurrence rate was 35.3% after a single procedure. The freedom-from-AF rates were 85.3% at 1 year and 73.3% at 5 years. In the baseline study, group 2 had larger left atrium (38 ± 4 mm vs 36 ± 5 mm, P = 0.04), left ventricle (50 ± 5 mm vs 46 ± 5 mm, P = 0.003), and PV diameters. Kaplan-Meier survival analysis showed a higher AF recurrence rate in group 2 compared to that in group 1 (P = 0.012). The independent predictor of an AF recurrence was a larger SVC diameter (P = 0.02, HR 1.4, 95% CI 1.1-1.8). Among the patients with paroxysmal AF originating from the SVC, 73% remained free of AF for 5 years after a single catheter ablation procedure. Superior vena cava isolation without PV isolation is an acceptable therapeutic strategy in those patients with AF originating from the SVC only. The SVC diameter was an independent predictor of AF recurrence. (J Cardiovasc Electrophysiol, Vol. 23, pp. 955-961, September 2012).
    Journal of Cardiovascular Electrophysiology 05/2012; 23(9):955-61. DOI:10.1111/j.1540-8167.2012.02337.x · 2.88 Impact Factor
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    ABSTRACT: Catheter ablation of atrial fibrillation (AF) became an effective therapy for patients with drug-refractory AF, and the indications have broadened to include nonparoxysmal AF patients. However, data about the long-term effectiveness of ablation in patients with nonparoxysmal AF are lacking. The aim of the present study was to investigate the long-term outcomes of catheter ablation in patients with nonparoxysmal AF. A total of 88 nonparoxysmal AF patients who received a stepwise catheter ablation (isolation of the pulmonary veins plus substrate modification) from 2006 to 2008 were enrolled. Freedom of recurrence was defined as the absence of atrial arrhythmias without using any antiarrhythmic agents after the catheter ablation. There were 63 patients (71.6%) with recurrences (47 patients with AF and 16 patients with atrial flutter/atrial tachycardia) after the initial procedure during a median follow-up period of 36.8 months. A CHADS2 score of ≥3 and the left atrial (LA) diameter were significant predictors of recurrences in the multivariable analysis. Of the patients with CHADS2 scores of ≥3 and an LA dimension≥44 mm, all had recurrences within 1 year after the initial procedure. The overall recurrence-free rate could increase to 47.7% after the second procedure and 51.1% after the third procedure. The long-term recurrence-free rate of ablation in nonparoxysmal AF was only 28.4% after a single procedure, and multiple procedures were necessary to raise the recurrence-free rate. The CHADS2 score and LA dimension may help us to identify patients who will have recurrences after catheter ablations of nonparoxysmal AF.
    Circulation Arrhythmia and Electrophysiology 05/2012; 5(3):514-20. DOI:10.1161/CIRCEP.111.968032 · 5.42 Impact Factor
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    ABSTRACT: Many cardiac diseases demonstrate seasonal variations in the incidence and mortality. This study was designed to investigate whether the mortality of infective endocarditis (IE) was higher in cool seasons and to evaluate the effects of cool climate for IE. We enrolled 100 IE patients with vegetations in our hospital. The temperatures of the IE episodes were defined as the monthly average temperatures of the admission days. The average temperatures in the cool (fall/winter) and warm seasons (spring/summer) were 19.2°C and 27.6°C, respectively. In addition, patients admitted with the diagnosis of IE were identified from the National Health Insurance Research Database (NHIRD) and the in-hospital mortality rates in cool and warm seasons were compared to validate the findings derived from the data of our hospital. The mortality rate for IE was significantly higher in fall/winter than in spring/summer which presents consistently in the patient population of our hospital (32.7% versus 12.5%, p = 0.017) and from NHIRD (10.4% versus 4.6%, p = 0.019). IE episodes which occurred during cool seasons presented with a higher rate of heart failure (44.2% versus 22.9%, p = 0.025) and D-dimer level (5.5 ± 3.8 versus 2.4 ± 1.8 μg/ml, p = 0.017) at admission than that of warm seasons. These results may reflect the impact of temperatures during the pre-hospitalized period on the disease process. In the multivariate analysis, Staphylococcal infection, left ventricular hypertrophy, left ventricular systolic dysfunction and temperature were the independent predictors of mortalities in IE patients.
    International Journal of Biometeorology 03/2012; 56(5):973-81. DOI:10.1007/s00484-011-0507-5 · 2.10 Impact Factor
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    ABSTRACT: Catheter ablation of paroxysmal atrial fibrillation has been performed for more than 10 years. However, data about the long-term results were limited. To evaluate the long-tem efficacy following paroxysmal atrial fibrillation ablation and to investigate whether there were different patterns of recurrences in patients with different CHADS(2) scores. A total of 238 patients with paroxysmal atrial fibrillation who received a catheter ablation from 2004 to 2007 were enrolled. Free of recurrence was defined as the absence of atrial arrhythmias without using any antiarrhythmic agents after ablation. There were 121 patients (50.8%) suffering from recurrences after the first ablation procedure during a median follow-up period of 5 years. The CHADS(2) score and left atrial diameter were significant predictors of recurrences in the multivariate analysis. Different patterns of recurrence were observed in different groups of patients categorized on the base of CHADS(2) score. Among patients with a CHADS(2) score of ≥3 without recurrences at 2 years postablation, 63.6% experienced episodes of arrhythmias during the subsequent follow-up period. In contrast, in patients with a CHADS(2) score of 0 without recurrences at 2 years postablation, the future recurrence rate was only 2.7%. After a successful ablation, recurrences may continue to occur without reaching a plateau during the long-term follow-up, especially in patients with a high CHADS(2) score. The optimal follow-up strategy may differ and should be individualized for patients with different scores.
    Heart rhythm: the official journal of the Heart Rhythm Society 03/2012; 9(8):1185-91. DOI:10.1016/j.hrthm.2012.03.007 · 4.92 Impact Factor
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    ABSTRACT: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a major cause of sudden cardiac death due to tachyarrhythmias. The purpose of this study was to investigate the long-term prognosis in patients with ARVC and the incidence of rapid ventricular arrhythmias during follow-up. Thirty ARVC patients (19 male, 63.3%, mean age 48 ± 15 years) fulfilling modified Task Force criteria 2010 were included. Of them, 13 patients (43.3%) received implantable cardioverter-defibrillator (ICD) implantation. Rapid ventricular arrhythmia was defined as electrical storm or the occurrence of ventricular tachycardia (VT) or ventricular fibrillation (VF) with a cycle length of 240 ms or less that necessitate shock delivery to 2 or more times within a 24-hour period. With a mean follow-up of 68 ± 10 months, 6 patients (20%) with ICD implantation had recurrent rapid VT/VF. One (3.3%) of them died of multiple shocks and SCD, and 5 (16.7%) had multiple ICD therapies due to VT/VF and electrical storm. The interval between the diagnosis of ARVC and occurrence of rapid VT/VF was 13.4 ± 4.9 months. Most (5/6, 83.3%) events of recurrent rapid VT/VF occurred within 2 years. Ablated patients who did not receive an ICD implant were totally free of rapid VT/VF. For patients with ARVC, long-term prognosis is favorable. During a long-term follow-up, patients meeting the criteria for ICD implantation have a higher rate of rapid and potentially life-threatening arrhythmias. However, early and clustered recurrence of rapid VT/VF in patients with an ICD is common, whereas late occurrence of rapid VT/VF is very rare.
    Journal of Cardiovascular Electrophysiology 02/2012; 23(7):750-6. DOI:10.1111/j.1540-8167.2011.02288.x · 2.88 Impact Factor
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    ABSTRACT: Heat shock protein (HSP) 27 is related to the pathogenesis of AF. However, the clinical relationship between HSP27 and AF is unclear. The present study was conducted to determine the clinical relationship between HSP27 and atrial fibrillation (AF). A case-control study was conducted (AF, n=114; control, n=100). Serum HSP27 (HSP27S) levels were measured by ELISA, and its correlations with electrophysiological characteristics and catheter ablation outcomes were investigated. The patients with AF had a larger left atrial diameter (LAD), waist circumference, and body mass index, and a lower baseline HSP27S level, than controls. After logistic multivariate analysis, low baseline HSP27S was independently associated with AF. In patients with AF, those with paroxysmal AF (PAF) had higher baseline HSP27S levels compared with those without PAF. In patients with PAF, lower baseline HSP27S was associated with larger LAD, whereas baseline HSP27S was not correlated with LAD in controls. In PAF, low baseline HSP27S (≤3.85 ng/mL) was associated with low atrial voltage and nonpulmonary vein ectopies. In non-PAF, the mean fractionated interval had a good correlation with baseline HSP27S. After catheter ablation, a high baseline HSP27S level could predict sinus rhythm maintenance in the patients with PAF. Baseline HSP27S was also correlated with interleukin 10 and tumor necrosis factor-α levels. Analysis of buffy coat mRNA levels showed the same correlations. The HSP27S levels were correlated with LAD, left atrial voltage, and fractionated intervals, and predicted AF recurrence after catheter ablation. The mechanisms could be related to inflammation.
    Circulation Arrhythmia and Electrophysiology 02/2012; 5(2):334-40. DOI:10.1161/CIRCEP.111.965996 · 5.42 Impact Factor
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    ABSTRACT: Late sodium currents and intracellular Ca(2+) (Ca(2+) (i)) dynamics play an important role in arrhythmogenesis of pulmonary vein (PV) and heart failure (HF). It is not clear whether HF enhances PV arrhythmogenesis through modulation of Ca(2+) homeostasis and increased late sodium currents. The aim of this study was to investigate the sodium and calcium homeostasis in PV cardiomyocytes with HF. METHODS AND RESULTS: Whole-cell patch clamp was used to investigate the action potentials and ionic currents in isolated rabbit single PV cardiomyocytes with and without rapid pacing induced HF. The Ca(2+) (i) dynamics were evaluated through fluorescence and confocal microscopy. As compared to control PV cardiomyocytes (n = 18), HF PV cardiomyocytes (n = 13) had a higher incidence of delayed afterdepolarization (45% vs 13%, P < 0.05) and faster spontaneous activity (3.0 ± 0.2 vs 2.1 ± 0.2 Hz, P < 0.05). HF PV cardiomyocytes had increased late Na(+) currents, Na(+) /Ca(2+) exchanger currents, and transient inward currents, but had decreased Na(+) currents or L-type calcium currents. HF PV cardiomyocytes with pacemaker activity had larger Ca(2+) (i) transients (R410/485, 0.18 ± 0.04 vs 0.11 ± 0.02, P < 0.05), and sarcoplasmic reticulum Ca(2+) stores. Moreover, HF PV cardiomyocytes with pacemaker activity (n = 18) had higher incidence (95% vs 70%, P < 0.05), frequency (7.8 ± 3.1 vs 2.3 ± 1.2 spark/mm/s, P < 0.05), amplitude (F/F(0) , 3.2 ± 0.8 vs 1.9 ± 0.5, P < 0.05), and longer decay time (65 ± 3 vs 48 ± 4 ms, P < 0.05) of Ca(2+) sparks than control PV cardiomyocytes with pacemaker activity (n = 18). CONCLUSIONS: Dysregulated sodium and calcium homeostasis, and enhanced calcium sparks promote arrhythmogenesis of PV cardiomyocytes in HF, which may play an important role in the development of atrial fibrillation.
    Journal of Cardiovascular Electrophysiology 12/2011; 22(12):1378-86. DOI:10.1111/j.1540-8167.2011.02126.x · 2.88 Impact Factor
  • Journal of Cardiovascular Electrophysiology 11/2011; 23(8):887-8. DOI:10.1111/j.1540-8167.2011.02229.x · 2.88 Impact Factor
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    ABSTRACT: The atrial substrate in chronic atrial fibrillation (AF) patients with a left atrial spontaneous echo contrast (LASEC) has not been previously reported. The aim of this study was to investigate the atrial substrate properties and long-term follow-up results in the patients who received catheter ablation of chronic AF. Of 36 consecutive patients with chronic AF who received a stepwise ablation approach, 18 patients with an LASEC (group I) were compared with 18 age-gender-left atrial volume matched patients without an LASEC (group II). The atrial substrate properties including the weighted peak-to-peak voltage, total activation time during sinus rhythm (SR), dominant frequency (DF), and complex fractionated electrograms (CFEs) during AF in the bi-atria were evaluated. The left atrial weighted bipolar peak-to-peak voltage (1.0 ± 0.6 vs 1.6 ± 0.7 mV, P = 0.04), total activation time (119 ± 20 vs 103 ± 13 ms, P < 0.001) and DF (7.3 ± 1.3 vs 6.6 ± 0.7 Hz, P < 0.001) differed between group I and group II, respectively. Those parameters did not differ in the right atrium. The bi-atrial CFEs (left atrium: 89 ± 24 vs 92 ± 25, P = 0.8; right atrium: 92 ± 25 vs 102 ± 3, P = 0.9) did not differ between group I and group II, respectively. After a mean follow-up of 30 ± 13 month, there were significant differences in the antiarrhythmic drugs (1.1 ± 0.3 vs 0.7 ± 0.5, P = 0.02) needed after ablation, and recurrence as persistent AF (92% vs 50%, P = 0.03) between group I and group II, respectively. After multiple procedures, there were more group II patients that remained in SR, when compared with group I (78% vs 44%, P = 0.04). There was a poorer atrial substrate, lesser SR maintenance after catheter ablation and need for more antiarrhythmic drugs in the chronic AF patients with an LASEC when compared with those without an LASEC.
    Journal of Cardiovascular Electrophysiology 09/2011; 23(3):239-46. DOI:10.1111/j.1540-8167.2011.02170.x · 2.88 Impact Factor

Publication Stats

2k Citations
702.99 Total Impact Points

Institutions

  • 2005–2015
    • National Yang Ming University
      • School of Medicine
      T’ai-pei, Taipei, Taiwan
    • Taipei Veterans General Hospital
      • Cardiology Division
      T’ai-pei, Taipei, Taiwan
  • 2011
    • Buddhist Tzu Chi General Hospital
      T’ai-pei, Taipei, Taiwan
  • 2009
    • Chung Shan Medical University
      • Institute of Medicine
      臺中市, Taiwan, Taiwan
    • University of the Ryukyus
      • Faculty of Medicine
      Okinawa, Okinawa, Japan