Arrhythmogenic difference between the left and right atria in a canine ventricular pacing-induced heart failure model of atrial fibrillation.

BACKGROUND: The detail of biatrial activation during sustained atrial fibrillation (AF) has not been investigated until now. METHODS: Five dogs with right ventricular pacing-induced congestive heart failure (CHF) and five normal dogs were included. Biatrial endocardiac mapping was performed using noncontact mapping system. RESULTS: Noncontact mapping of the right atrium (RA) showed CHF dogs had a higher frequency of focal discharge from Bachmann's bundle, sinoatrial region, and crista terminalis. CHF dogs also had a higher frequency of wave break, wave fusion, and reentry. CHF dogs had greater effective refractory period (ERP) dispersion. Noncontact mapping of the left atrium (LA) showed CHF dogs had more frequent focal discharge from left superior pulmonary vein (PV), right superior PV, and left atrial appendage. CHF dogs had a higher frequency of wave break, wave fusion, and reentry. CHF dogs had greater ERP dispersion. Comparison between RA and LA showed LA had a higher frequency of focal discharge, wave break, wave fusion, and leading circle reentry than the RA. LA also had greater ERP dispersion than RA. CONCLUSION: CHF dogs had a higher frequency of focal discharge and reentry, suggesting that CHF provided an arrhythmogenic substrate. LA had a higher frequency of focal discharge and reentry, suggesting that LA is more important to maintain AF.

Electrophysiological correlation and prognostic impact of heat shock protein 27 in atrial fibrillation.

BACKGROUND: 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). METHODS AND RESULTS: 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. CONCLUSIONS: 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.

Characteristics of fibrillatory activities during spontaneous termination of paroxysmal atrial fibrillation: new insight from high-density right atrium frequency mapping.

BACKGROUND: Sinus node (SN) activity is difficult to assess during atrial fibrillation (AF). The aim of the present study was to investigate SN activity by frequency analysis during AF. METHODS: Thirteen patients with paroxysmal AF and atrial flutter in the right atrium (RA) underwent 3-dimensional noncontact mapping. The fibrillatory activity was recorded from a multielectrode array in the RA. A frequency analysis with 2- and 6-second time-segment lengths was performed. Spectral characteristics (dominant frequency and harmonic index) and isopotential activation maps were used to investigate the spatiotemporal activity of the SN region and the rest of the RA (crista terminalis, septum, and free wall) during the initiation, while ongoing, and before the termination of AF. RESULTS: With duration of 6 seconds, the whole RA had similar trends of frequency distribution. With duration of 2 seconds prior to termination, the SN region exhibited a trend of low-frequency pattern and high-organization distribution, compared with the segments for the 2 to 4 and 4 to 6 seconds before termination. The isopotential activation maps showed the spontaneous earliest activities had wave front propagation patterns similar to those during sinus rhythm (after termination). CONCLUSIONS: The fibrillatory activity of the SN region was organized, and slow activation was detected, by frequency analysis and isopotential mapping, within 2 seconds just prior to AF termination.

Characteristics and significance of very early recurrence of atrial fibrillation after catheter ablation.

INTRODUCTION: Early restoration of sinus rhythm following ablation of atrial fibrillation (AF) facilitates reverse atrial remodeling and improves the long-term outcome. The purpose of this study was to determine the predictors and outcome in patients with very early AF recurrences (< 2 days). METHODS AND RESULTS: Ablation was performed in 339 consecutive AF patients (paroxysmal AF = 262). Biatrial voltage was mapped during sinus rhythm. If recurrent AF occurred within 2 days following the ablation, electrical cardioversion was performed to restore sinus rhythm. Very early recurrences of AF occurred in 39 (15%) patients with paroxysmal AF and 26 (34%) with nonparoxysmal AF. Patients with very early recurrence had a higher incidence of nonparoxysmal AF (40% vs 18.6%, P< 0.001), requirement of electrical cardioversion during procedure, larger left atrial (LA) diameter (43 ± 7 vs 39 ± 6 mm, P< 0.001), lower left ventricular ejection fraction (54 ± 10% vs 59 ± 7, P< 0.001), longer procedural time, and lower LA voltage (1.5 ± 0.7 vs 1.9 ± 0.8 mV, P< 0.001). A multivariate analysis revealed that the independent predictors of a very early recurrence were a longer procedural time and lower LA voltage. During a follow-up of 13 ± 5 months, a very early recurrence did not predict the long-term outcome of a single procedure recurrence in the patients with paroxysmal AF, but was associated with a late recurrence in the nonparoxysmal AF patients. CONCLUSION: Very early recurrence occurred in patients with paroxysmal AF is not associated with long-term recurrence. Nonparoxysmal AF is an independent predictor of late recurrence of AF in patients with very early recurrence.

Paradoxical aging changes of the atrioventricular nodal properties in patients with atrioventricular nodal re-entrant tachycardia.

BACKGROUND: This study aimed to investigate the impact of aging on electrophysiological characteristics in patients with atrioventricular nodal re-entrant tachycardia (AVNRT). METHODS AND RESULTS: The 2,111 patients who underwent an electrophysiological study and radiofrequency (RF) catheter ablation of AVNRT were enrolled. The patients were divided into 4 groups according to age (group 1: < 20 years; group 2: 20-39 years; group 3: 40-59 years; and group 4: ≥ 60 years). The gender distribution differed with age. The atrio-Hisian interval, and effective refractory periods (ERP) of the right atrium, ventricle, antegrade slow pathway, retrograde slow pathway and fast pathway, and tachycardia cycle length all increased with age. However, a paradoxical change in the fast pathway ERP was noted. The fast pathway ERP was significantly longer in group 2 than in other groups, and was associated with the largest tachycardia window. The response to catecholamines was similar between different age groups. Procedure time, radiation time, and complications did not differ. However, the number of RF impulses was higher in group 2 compared with other groups (7.6 ± 9.3, P=0.04), which might imply a differing complexity during the ablation. CONCLUSIONS: Paradoxical aging changes of AVN electrophysiological characteristics were associated with a different atrioventricular nodal conduction property and the number of RF impulses.

Quantitative analysis of quantity and distribution of epicardial adipose tissue surrounding the left atrium in patients with atrial fibrillation and effect of recurrence after ablation.

Epicardial adipose tissue (EAT) contains ganglionated plexuses and adipocytes that can affect the pathogenesis of atrial fibrillation (AF). The aim of this study was to quantify the EAT surrounding the left atrium (LA) and correlate it with occurrence of AF and outcome after catheter ablation. EAT was evaluated using 64-slice multidetector computed tomography in 68 patients with AF and 34 controls. EAT volume was acquired by semiautomatically tracing axial images from the pulmonary artery to the coronary sinus. Topographic distribution of EAT was assessed by dividing the periatrial space into 8 equal regions. EAT volume significantly increased in patients with AF than in controls (29.9 ± 12.1 vs 20.2 ± 6.5 cm(3), p <0.001). Most EAT was located in regions (1) within the superior vena cava, right pulmonary artery, and right-sided roof of the LA (29.8%), (2) within the aortic root, pulmonary trunk, and left atrial appendage (26.5%), and (3) between the left inferior pulmonary vein and left atrioventricular groove (18.1%). Baseline variables were analyzed in patients with (n = 24) and without (n = 44) AF recurrence after ablation. The recurrent group showed significantly increased EAT (35.2 ± 12.5 vs 26.8 ± 11.1 cm(3), p = 0.007). Multivariate analysis revealed that EAT was an independent predictor of AF recurrence after ablation (p = 0.038). In conclusion, EAT of LA was increased in patients with AF. Large clusters of EAT were observed adjacent to the anterior roof, left atrial appendage, and lateral mitral isthmus. Abundance of EAT was independently related to AF recurrence after ablation.

The correlation between ventricular repolarization and clinical severity of spinal cord injuries.

BACKGROUND: Alteration in ventricular repolarization has been reported in patients with spinal cord injuries (SCIs). However, its clinical impact remains unclear. OBJECTIVE: The purpose of this study was to investigate the correlation between SCIs and ventricular repolarization and the associated clinical impact. METHODS: One hundred forty-four patients with an SCI were retrospectively reviewed and were divided into two groups (SCI level ≤ T6, n = 110; SCI level >T6, n = 34). The electrocardiograms were reviewed during acute phase (at emergency room) and chronic phase (>1 year). RESULTS: There were no differences in the underlying diseases or in ASIA score between the two groups, except there were more patients with tetraplegia among those with an SCI level ≤ T6. For the electrophysiological parameters from the electrocardiograms, the patients with an SCI level ≤ T6 had longer QTc and PR interval than those with an SCI level >T6 during acute phase. In the chronic phase, there were no differences in the electrophysiological parameters between the two groups. Only in patients with an SCI level ≤ T6 did a Kaplan-Meier analysis show that QTc prolongation could predict 30-day mortality after the acute injury. After multivariate Cox regression analysis, only tetraplegia and QTc prolongation were independent predictors of 30-day mortality (odds ratios 7.85 and 34.62, respectively). In patients with an SCI level ≤ T6, the QTc intervals were shorter in the chronic phase than those during the acute phase. CONCLUSION: QTc interval was associated with the level of acute SCI and predicted the 30-day mortality.

The distance between the vein and lesions predicts the requirement of carina ablation in circumferential pulmonary vein isolation.

AIMS: Additional ablation in the pulmonary vein (PV) carina region is sometimes required to achieve electrical isolation following circumferential pulmonary vein isolation (PVI). This study investigated the procedural predictors for the requirement of additional carina ablation to achieve complete electrical isolation with PVI. METHODS AND RESULTS: Eighty patients with drug-refractory paroxysmal AF underwent circumferential PVI. After the first round of PVI, we placed circular catheters inside the veins to identify the residual PV potentials, and also performed electroanatomic mapping to observe the earliest activation sites during sinus rhythm. The requirement of an additional gap and carina ablation, and the optimal distance that predicted an incomplete PV block were assessed. In the first 40 patients, 43% of the ipsilateral PVs were electrically isolated after the initial PVI. Subsequent ablation of the gaps and ablation of the carina were required in the remaining 57% PVs. The only predictor of the requirement of carina ablation was the mean distance between the lesion-related scar and the ostia (P = 0.03). The longer the distance from the isolating lesions to the PV ostia (>8 mm) predicted an incomplete PV isolation after the first round of circumferential isolation. In the next 40 patients, a fixed distance of 8 mm to the PV ostia decreased the requirement of a carina ablation and resulted in a shorter procedure time (P < 0.05). CONCLUSIONS: This study indicated the importance of complete linear lesions and additional carina ablation when the wide area circumferential PV isolation was applied.

Impact of circulating monocyte CD36 level on atrial fibrillation and subsequent catheter ablation.

BACKGROUND: Inflammation, an important mechanism in the pathogenesis of atrial fibrillation (AF), can be regulated by CD36 in monocytes. OBJECTIVE: The purpose of this study was to test the hypothesis that CD36 in monocytes contributes to the pathogenesis of AF. METHODS: A prospective study that enrolled 87 patients with AF and 70 without AF was conducted. RESULTS: Compared to patients without AF, patients with AF had monocytes with a lower level of CD36 protein, which correlated with left atrial diameter, left atrial emptying fraction, and left atrial mean voltage. In AF patients after catheter ablation, Kaplan-Meier analysis showed that the sinus rhythm maintenance rate was higher in patients with high CD36 levels. Low CD36 level was an independent predictor of recurrence. After successful ablation, the CD36 level increased by 57%, reaching that of control patients. CD36 level was not correlated with the level of high-sensitivity C-reactive protein. Analysis of mRNA levels from a buffy coat revealed that AF patients had lower CD36 and interleukin-10 levels and higher peroxisome proliferator-activated receptor-γ and tumor necrosis factor-α levels, with CD36 level positively correlated with interleukin-10 level but inversely correlated with peroxisome proliferator-activated receptor-γ and tumor necrosis factor-α levels. CONCLUSION: Low CD36 levels in circulating monocytes were associated with AF occurrence and predicted recurrence after catheter ablation. The link between CD36 and AF identified a novel AF-related inflammatory pathway.

Differentiating macroreentrant from focal atrial tachycardias occurred after circumferential pulmonary vein isolation.

BACKGROUND: Atrial tachycardias (ATs) are commonly observed following catheter ablation of atrial fibrillation (AF). The aim of this study was to identify ECG characteristics that differentiate focal from macroreentrant ATs after circumferential pulmonary vein isolation (CPVI). METHODS AND RESULTS: One hundred and twenty ATs that occurred after CPVI were mapped using a 3-dimensional mapping system in 87 patients with AF. Further ablation was performed to eliminate the ATs. The surface ECGs of 68 ATs in 41 consecutive patients (Group 1) were analyzed retrospectively to create diagnostic algorithms. The algorithms were tested in the second 46 consecutive patients (Group 2). Patients with macroreentrant AT had lower left atrial (LA) voltage than those with focal AT (1.3 ± 0.3 vs 1.5 ± 0.2 mV, P = 0.01). Focal AT had a higher incidence of a positive polarity in V6 compared with macroreentrant AT (88% vs 55%, P = 0.03). The positive amplitude of the flutter/P waves in V6 was higher for focal AT than macroreentrant AT. The cycle lengths of the focal ATs were longer than those for macroreentrant AT (296 ± 107 vs 244 ± 25 ms, P < 0.001). Right atrial macroreentrant AT had a higher incidence of a negative polarity in at least 1 precordial lead compared with LA macroreentry. The positive flutter waves in V1 could differentiate roof/mitral isthmus dependent from non-roof/mitral isthmus dependent macroreentry. This algorithm correctly differentiated the focal from macroreentrant ATs with a sensitivity of 94%, specificity of 91%, and predictive accuracy of 92% in Group 2. CONCLUSION: Different electrophysiological properties may facilitate the differentiation between macroreentrant and focal ATs after CPVI.

Different patterns of atrial remodeling after catheter ablation of chronic atrial fibrillation.

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.

Relationship between arrhythmogenic pulmonary veins and the surrounding atrial substrate in patients with paroxysmal atrial fibrillation.

INTRODUCTION: The relationship between pulmonary veins (PVs) with atrial fibrillation (AF) initiating triggers and their surrounding atrial substrate has not been elucidated. We aimed to clarify the atrial substrate properties around the PVs. METHODS AND RESULTS: Twenty-three paroxysmal AF patients were studied with the identification of PV initiating triggers. High-density mapping of the dominant frequency (DF, 1200 Hz) and the mean degree of the complex fractionated electrograms (CFE mean interval over 6 seconds) was evaluated in 2 zones (zone 1: < 5 mm, zone 2: 5-15 mm from the PVs) and the left atrial (LA) using a NavX system prior to the PV isolation. High-DFs (>8 Hz) and continuous CFEs (<50 ms) were identified in 1.5 ± 0.9 and 2.3 ± 1.1 regions per patient, respectively. Most of the high-DF regions (86%) and continuous CFE regions (77%) were located within 15 mm of the PV ostia. Of those, 75% of the high-DF regions and 54% of the continuous CFE regions were related to arrhythmogenic PVs. There was a significant DF gradient from arrhythmogenic PV zone 1 to zone 2, while the mean CFE exhibited a significant gradient between arrhythmogenic PV zone 2 and the rest of the LA. Additionally, 69% of the procedural AF termination sites were at arrhythmogenic PV zone 2. CONCLUSION: Evaluation of the atrial substrate properties may be useful for locating arrhythmogenic PVs during AF and defining the extent of the circumferential PV isolation.

Characterization of the dynamic function of the pulmonary veins before and after atrial fibrillation ablation using multi-detector computed tomographic images.

Understanding pulmonary vein (PV) function before and after catheter ablation can validate the benefit of the treatment and provide mechanistic insight into atrial fibrillation (AF). This study was aimed to investigate the functional remodeling process of PVs by multi-detector computed tomography (MDCT). We assessed the dynamic function of four PVs by MDCT at systolic and diastolic phases. Twelve points around each PV ostium were used to assess the magnitude and abnormalities of the regional wall motion. The axis of PV shifting during cardiac cycle was also determined. Seventy-four paroxysmal AF patients and 29 controls were enrolled. In those of AF, the superior PVs had poorer contractile function (ejection fraction: P = 0.01 for left; P = 0.009 for right; magnitude of the motion: P = 0.01 for left; P = 0.02 for right) which mainly resulted from the decreased movement of the posterior wall. In contrast, the function of inferior PVs was similar between two groups. After a mean follow-up of 158 ± 95 days, the PV motion improved in the patients without any AF recurrence. In addition, analysis of the pre-ablation PV function showed that the angles, which shifted during cardiac cycle of left (P = 0.035) and right (P = 0.014) inferior PV, were significantly decreased in recurrent patients. The contractile function of the superior PVs was impaired in paroxysmal AF patients. This was attributed to the hypokinesia of the posterior wall of PVs and improved after circumferential ablation in the patients without recurrence. MDCT images can effectively delineate the functional characteristics of PVs.

Gender differences of electrophysiologic characteristics in patients with accessory atrioventricular pathways.

BACKGROUND: Few epidemiologic data on the gender differences among patients with accessory atrioventricular pathways have been reported. OBJECTIVE: The purpose of this study was to investigate the explicit gender differences in electrophysiologic characteristics among patients with accessory atrioventricular pathways. METHODS: A total of 1,821 consecutive patients with accessory atrioventricular pathways were referred to our institution for electrophysiologic study and radiofrequency catheter ablation. A detailed electrophysiologic study was performed in all patients. RESULTS: Patient age at onset of atrioventricular reentrant tachycardia was 43 ± 17 years. There were 1,117 males (61.3%) with accessory atrioventricular pathways. Men had more manifest and left-sided but fewer multiple accessory pathways. Men had more antidromic atrioventricular reentrant tachycardia. Men had a shorter anterograde accessory pathway effective refractory period (ERP) and a higher prevalence of an anterograde accessory pathway ERP (<250 ms). Men with accessory atrioventricular pathways had a longer atrioventricular nodal ERP and atrial ERP and a shorter ventricular ERP. CONCLUSION: Gender differences in the clinical and electrophysiologic characteristics of patients with accessory atrioventricular pathways could be closely linked and may imply a different pathogenesis.

The impact of age on the electrophysiological characteristics and different arrhythmia patterns in patients with Wolff-Parkinson-White syndrome.

INTRODUCTION: Information about the impact of age on the electrophysiological characteristics of accessory pathways (APs) in patients with Wolff-Parkinson-White (WPW) syndrome remains limited. METHODS AND RESULTS: A total of 1,885 consecutive patients (mean age 43 ± 17 years, male 61.5%) with WPW syndrome who were referred to the tertiary center for an electrophysiological study and radiofrequency catheter ablation were investigated. The patients were divided into 4 groups based on their age (Group 1: <20; Group 2: 20-39; Group 3: 40-59; Group 4: ≧60 years old). With age, more left-sided APs (53.2%, 67.7%, 71.7%, 75.7%, P < 0.001) and a longer duration of the arrhythmia (4.3 ± 2.8 years, 10.1 ± 7.0 years, 12.4 ± 10.9 years, 14.0 ± 12.4 years, P < 0.001) were noted. The incidence of concealed APs (53.5%, 53.0%, 57.8%, 60.9%, P = 0.01), and orthodromic atrioventricular (AV) reentrant tachycardia (92.4%, 94.2%, 96.5%, 96.3%, P = 0.023) increased with age. The tachycardia cycle length, antegrade (275.5 ± 42.2 ms, 286.7 ± 62.7 ms, 302.5 ± 66.5 ms, 315.2 ± 80.2 ms, P < 0.001) and retrograde AP effective refractory periods (APERPs) (254.0 ± 42.5 ms, 263.3 ± 51.8 ms, 274.5 ± 100.5 ms, 292.7 ± 57.0 ms, P < 0.001), atrial ERP, antegrade AV node effective refractory period (AVNERP), and ventricular effective refractory period (VERP) lengthened as the age increased. The incidence of decremental APs, multiple APs, and a catecholamine response were similar. The duration of the catheter ablation, total fluoroscopy time, acute success rate, complication rate, and incidence of a secondary procedure were similar between the different age groups. CONCLUSION: The electrophysiological characteristics and pattern of the arrhythmic attack associated with the AP changed with age.

Atrial substrate properties and outcome of catheter ablation in patients with paroxysmal atrial fibrillation associated with diabetes mellitus or impaired fasting glucose.

Diabetes mellitus has been reported to be an independent risk factor of atrial fibrillation (AF). The present study investigated the atrial substrate properties and clinical outcome of catheter ablation in patients with paroxysmal AF and abnormal glucose metabolism. A total of 228 patients with paroxysmal AF who had undergone catheter ablation for the first time were enrolled. An abnormal glucose metabolism (n = 65) was defined as diabetes mellitus or an impaired fasting glucose. We analyzed the clinical and electrophysiologic characteristics in, and the clinical outcome of, patients with AF with and without an abnormal glucose metabolism. The right atrial (107.2 ± 15.4 vs 96.0 ± 16.5 ms, p < 0.001) and left atrial (108.4 ± 22.3 vs 94.0 ± 17.5 ms, p < 0.001) total activation times were significantly longer in the patients with AF and an abnormal glucose metabolism than in those without an abnormal metabolism. Furthermore, the right atrial (1.46 ± 0.61 vs 2.00 ± 0.70 mV, p < 0.001) and left atrial (1.48 ± 0.74 vs 2.05 ± 0.78 mV, p < 0.001) bipolar voltages were significantly lower in those with AF and an abnormal glucose metabolism than in those without. The AF recurrence rate was also greater in the patients with an abnormal glucose metabolism (18.5% vs 8.0%, p = 0.022) than in those without. The follow-up duration was 18.8 ± 6.4 months. In conclusion, an abnormal glucose metabolism affects the biatrial substrate properties with an intra-atrial conduction delay, decreased voltage, and greater recurrence rate after catheter ablation.

The impact of diastolic dysfunction on the atrial substrate properties and outcome of catheter ablation in patients with paroxysmal atrial fibrillation.

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.

Gender differences in the clinical characteristics and atrioventricular nodal conduction properties in patients with atrioventricular nodal reentrant tachycardia.

INTRODUCTION: The detailed electrophysiological characteristics of the gender differences associated with atrioventricular nodal reentrant tachycardia (AVNRT) have not been clarified. This study investigated the gender-related electrophysiological differences in a large series of patients undergoing radiofrequency catheter ablation. METHODS AND RESULTS: A total of 2,088 consecutive AVNRT patients (men/women 869/1,219) who underwent catheter ablation were enrolled in this study. We evaluated the gender differences in their electrophysiological characteristics. Women had a significantly younger age of onset, higher incidence of multiple jumps, shorter AH interval, atrial effective refractory period (ERP), anterograde fast pathway ERP, anterograde slow pathway ERP, and retrograde slow pathway ERP, and longer ventricular ERP than men. The incidence of baseline ventriculoatrial dissociation was lower in women than in men. Women needed less isoproterenol/atropine to induce AVNRT. No gender differences in the radiation exposure time, procedure time, complication rate, acute success rate, or second procedure rate were noted. Both typical and atypical AVNRT were more predominant in women. In the patients with atypical AVNRT, there was no significant gender difference in incidence of baseline ventriculoatrial dissociation; however, the retrograde slow pathway ERP was significantly shorter in women than in men. Women of premenopausal age (≤50 years old) had a significantly higher incidence of anterograde multiple jumps and a retrograde jump phenomenon, and a shorter anterograde slow pathway ERP and retrograde slow pathway ERP than those of women over 50 years old. CONCLUSION: Gender differences in the anterograde and retrograde AV nodal electrophysiology were noted in the patients with AVNRT.

The impact of age on the electroanatomical characteristics and outcome of catheter ablation in patients with atrial fibrillation.

BACKGROUND: Previous studies have indicated that atrial fibrillation (AF) in patients over the age of 60 at diagnosis is a risk factor for a substantial increase in cardiovascular events. However, information about the impact of age on the atrial substrate and clinical outcome after catheter ablation of AF is limited. METHODS: This study included 350 patients (53 ± 12 years, 254 males) who underwent circumferential pulmonary vein isolation (CPVI) of AF, guided by a NavX mapping system. The subjects were divided into three groups according to their age, as follows: Group I: age ≤50 (n = 141), Group II: age = 51-64 (n = 149) and Group III: age ≥65 years old (n = 60). The mean voltage and total activation time of the individual atria were obtained by using a NavX mapping system before ablation. Several parameters, including the gender, AF duration, and left atrial (LA) diameter were analyzed. RESULTS: The younger age group had a significantly smaller LA diameter (Group I vs Group II vs Group III, 36.89 ± 7.11 vs 39.16 ± 5.65 vs 40.77 ± 4.95 mm, P = 0.002) and higher LA bipolar voltage (2.09 ± 0.83 vs 1.73 ± 0.73 vs 1.86 ± 0.67 mV, respectively, P = 0.024), compared with the older AF patients. The LA bipolar voltage exhibited a significant reduction when the patients became older, however, that did not occur in the right atrium. The incidence of an AF recurrence was higher in the older age group than in the younger age groups. A subgroup of patients with lone AF was analyzed and age was found to be an independent predictor of the AF recurrence after receiving the first CPVI in the multivariable model (P < 0.05). CONCLUSIONS: Age has a significant impact on the LA substrate properties and outcome of the catheter ablation of AF.

Prognostic implications of the high-sensitive C-reactive protein in the catheter ablation of 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.