Interatrial septal thickness as a marker of structural and functional remodeling of the left atrium in patients with atrial fibrillation.

BACKGROUND/AIMS: There have been reports that interatrial septal (IAS) thickness is increased in patients with atrial fibrillation (AF). This study was performed to investigate whether IAS thickness determined by transthoracic echocardiography (TTE) represents the amount of left atrium (LA) structural and functional remodeling. METHODS: The study population consisted of 104 consecutive patients who underwent catheter ablation (CA) for AF (paroxysmal atrial fibrillation [PAF], 82; persistent atrial fibrillation [PeAF], 22). IAS thickness and left atrium volume (LAV) using TTE, and LA voltage (LA(VOL)) using 3-dimensional electroanatomical mapping system were assessed during sinus rhythm. RESULTS: IAS thickness was significantly correlated with maximal LAV (LAV(max)) (r = 0.288, p = 0.003), mean LA(VOL) (r = -0.537, p < 0.001), total left atrium emptying fraction (LAEF(total); r = -0.213, p = 0.030), and active LAEF (LAEF(active); r = -0.249, p = 0.014). IAS thickness was greater in the high-risk group (≥ 2) compared to other groups according to CHA2DS2-VASc score (p = 0.019). During a follow-up of 19.6 months, 23 subjects (22.1%; PAF, 17; PeAF, 6) had recurrence of arrhythmia. Univariate analysis showed that LAV(max), minimal LAV, mean LA(VOL), LVEF(total), LVEF(active), and IAS thickness were associated with recurrence of arrhythmia. However, on multivariate analysis, only mean LA(VOL) and LAEF(active) were independent risk factors for recurrence. CONCLUSIONS: Although IAS thickness showed significant correlations with parameters for LA structural and functional remodeling, this parameter alone could not independently predict recurrence of arrhythmia after CA for AF.

Interatrial septal thickness is associated with the extent of left atrial complex fractionated atrial electrograms and acute procedural outcome in patients with persistent atrial fibrillation.

AIMS: The interatrial septal thickness (IAST) reflects the changes of the atrial wall in patients with atrial fibrillation (AF). Complex fractionated atrial electrograms (CFAEs) were consistently positioned on the interatrial septum, especially in the remodelled left atrium (LA). We sought to characterize the relationship between IAST and LA CFAE area, as well as the acute procedural and clinical outcomes of catheter ablation in persistent AF patients. METHODS AND RESULTS: This study included 71 patients who underwent catheter ablation for drug-refractory persistent AF. A stepwise ablation approach included circumferential pulmonary vein isolation followed by LA and right atrial CFAE-guided ablation. Interatrial septal thickness was measured 1 cm inferior to the fossa ovalis on cardiac computed tomography (CT). The extent of LA CFAEs was assessed by CFAE area and index (CFAE area/LA surface area × 100). Patients were grouped into tertiles according to the value of IAST. The mean IAST of the first, second, and third tertile was 4.69 ± 0.79, 6.44 ± 0.45, and 9.12 ± 1.42 mm, respectively (P < 0.001). The mean CFAE areas (5.6 ± 6.9, 18.5 ± 20.3, and 24.3 ± 26.6 mm(2), P = 0.005) and CFAE indexes (3.1 ± 4.2, 9.2 ± 10.7, and 11.8 ± 15.3, P = 0.025) in LA were significantly different among the three groups. More patients in the highest IAST tertile did not terminate AF during catheter ablation (12.5% vs. 26.1% vs. 37.5%, P = 0.048). CONCLUSIONS: Interatrial septal thickness measured by cardiac CT is associated with the extent of CFAE area within the LA and is related to acute procedural success of catheter ablation. These findings suggest that IAST reflects the degree of atrial substrate and remodelling in patients with persistent AF.

Impact of low dose atorvastatin on development of new-onset diabetes mellitus in Asian population: Three-year clinical outcomes.

BACKGROUND: High dose atorvastatin is known to be associated with new onset diabetes mellitus (NODM) in patients with high risk for developing diabetes mellitus (DM). However, low dose atorvastatin is more commonly used as compared with high dose atorvastatin. The aim of this study is to investigate the impact of low dose atorvastatin (LDA, 10mg or 20mg) on the development of NODM up to three years in Asian patients. METHODS: From January 2004 to September 2009, we investigated a total of 3566 patients who did not have DM. To adjust for potential confounders, a propensity score matching (PSM) analysis was performed using the logistic regression model. After PSM (C-statistics: 0.851), a total of 818 patients (LDA group, n=409 patients and control group, n=409 patients) were enrolled for analysis. RESULTS: Before PSM, the cumulative incidence of NODM (5.8% vs. 2.1%, p<0.001), myocardial infarction (0.5% vs. 0.1%, p-value=0.007), and major adverse cardio-cerebral event (MACCE, 1.8% vs. 0.7%, p-value=0.012) at three-years were higher in the LAD group. However, after PSM, there was a trend toward higher incidence of NODM (5.9% vs. 3.2%, p=0.064) in the LDA group, but the incidence of MACCE (1.2% vs. 1.5%, p-value=1.000) was similar between the two groups. In multivariable analysis, the LDA administration was tended to be an independent predictor of NODM (OR: 1.99, 95% CI: 1.00-3.98, p-value 0.050). CONCLUSIONS: In this study, the use of LDA tended to be a risk factor for NODM in Asian patients and reduced clinical events similar to the control group. However, large-scale randomized controlled trials will be needed to get the final conclusion.

Does isolation of the left atrial posterior wall improve clinical outcomes after radiofrequency catheter ablation for persistent atrial fibrillation?: A prospective randomized clinical trial.

INTRODUCTION: Although posterior wall of left atrium (LA) is known to be arrhythmogenic focus, little is known about the effect of posterior wall isolation (PWI) in patients who undergo radiofrequency catheter ablation (RFCA) for persistent atrial fibrillation (PeAF). METHODS: We randomly assigned 120 consecutive PeAF patients to additional PWI [PWI (+), n=60] or control [PWI (-), n=60] groups. In all patients, linear ablation was performed after circumferential pulmonary vein isolation (PVI). Linear lesions included roof, anterior perimitral, and cavotricuspid isthmus lines with conduction block. In PWI (+) group, posterior inferior linear lesion was also conducted. Creatine kinase-MB (CK-MB) and troponin-T levels were measured 1day after RFCA. LA emptying fraction (LAEF) was assessed before and 12 months after RFCA. RESULTS: A total of 120 subjects were followed for 12 months after RFCA. There were no significant differences between two groups in baseline demographics and LA volume (LAV). The levels of CK-MB and troponin-T and procedure time were not significantly different between the groups. AF termination during RFCA was more frequently observed in PWI (+) than control (P=0.035). During follow-up period, recurrence occurred in 10 (16.7%) patients in PWI (+) and 22 (36.7%) in control (P=0.02). The change in LAEF was not significantly different between the groups. On multivariate analysis, smaller LAV and additional PWI were independently associated with procedure outcome. CONCLUSIONS: PWI in addition to PVI plus linear lesions was an efficient strategy without deterioration of LA pump function in patients who underwent RFCA for PeAF.

Does the amount of atrial mass reduction improve clinical outcomes after radiofrequency catheter ablation for long-standing persistent atrial fibrillation? Comparison between linear ablation and defragmentation.

BACKGROUND: Although a large isolated surface area of the left atrium (LA) may improve the success rate of catheter ablation (CA) for paroxysmal atrial fibrillation (AF), little is known about the relation between clinical outcomes and the amount of atrial mass reduction (AMR: ratio of total isolated and ablated areas to LA surface area) in different ablation strategies for patients with long-standing persistent AF (L-PeAF). METHODS: We randomly assigned 119 consecutive L-PeAF patients to adjunctive linear ablation (n=60) or complex fractionated atrial electrogram (CFAE)-guided ablation (n=59) after circumferential antral pulmonary vein isolation (PVI). Linear lesions included roof and anterior lines with conduction block. LA defragmentation was performed with an automated CFAE-detection algorithm. Cavotricuspid isthmus block was performed in all patients. Creatine kinase-MB (CK-MB) and troponin-T levels were measured 1 day post-CA. RESULTS: CK-MB and troponin-T levels were higher, ablation time was longer, and AMR was greater in the CFAE-guided ablation group than in the linear ablation group. AF termination during CA was more frequently observed in the linear ablation group than in the CFAE-guided ablation group (P=0.031). Twelve months after a single procedure, recurrence occurred in 16 (26.7%) patients with linear ablation and 27 (45.8%) patients with CFAE-guided ablation (P=0.023). On multivariate analysis, LA volume and ablation method were the only independent risk factors for arrhythmia recurrence. CONCLUSION: Conduction block through linear lines+PVI was an efficient ablation strategy for L-PeAF, whereas the AMR amount did not influence clinical outcomes.

Relationship between complex fractionated atrial electrograms during atrial fibrillation and the critical site of atrial tachycardia that develops after catheter ablation for atrial fibrillation.

INTRODUCTION: Complex fractionated atrial electrograms (CFAEs) are a substrate modification target in patients with atrial fibrillation (AF). However, whether CFAEs can be also arrhythmogenic grounds of atrial tachycardia (AT) presenting after AF ablation remains to be determined. We investigated the relationship between CFAEs and the critical site of AT after CFAE-guided AF ablation. METHODS AND RESULTS: Seventy-two patients showing AT after pulmonary vein isolation and further CFAE-guided ablation were included. The termination sites of the 95 distinct ATs were annotated on color-coded CFAE cycle maps. Of the 95 ATs, 61 (64.2%) had a termination site at the border zone of CFAE or in a highly dense CFAE area. The cycle length (CL) of the ATs terminated in the CFAE area was significantly shorter than the CL of those terminated in the non-CFAE area. The cut-off CL for ATs terminated at the CFAE area was 270 milliseconds, with sensitivity/specificity of 70%/75%. In 67.2% of the ATs terminating at the CFAE-related area, the major termination sites were the anterior wall near the LA appendage, septum and roof, whereas the peri-mitral isthmus was the most common termination site of ATs in the non-CFAE area. CONCLUSIONS: The areas showing CFAE and their border zones were frequently associated with termination of ATs presenting after AF ablation. The mean CL of ATs originating near CFAEs was significantly shorter than that of those terminated in non-CFAE areas. The targeted CFAE areas also provided the arrhythmogenic milieu for AT developing after AF ablation.

Clinical significance of induced atrial tachycardia after termination of longstanding persistent atrial fibrillation using a stepwise approach.

INTRODUCTION: The utility of inducibility test of atrial tachycardia (AT) in patients with longstanding persistent atrial fibrillation (AF; LPAF) is unclear. This study aimed to evaluate the significance of induced AT and the impact of their ablation on the clinical outcome. METHODS: In 194 patients with LPAF (>1 year) who underwent catheter ablation (pulmonary vein isolation with substrate ablation), an inducibility test was performed after AF termination. RESULTS: AT was induced in 108 (56%) patients (induced AT group); neither AT nor AF was inducible in 37 (19%, noninduction group). During 39 ± 21 months, AT recurred in 30 patients (28%), AF in 19 (17%), and no arrhythmia in 56 (52%) among induced AT group, although there was a recurrence of AT in 9 (24%, P = 0.68), AF in 6 (16%, P = 0.85), and no arrhythmia in 22 (60%, P = 0.42) among noninduction group (P = NS). Note that 10 patients with repeated ablation in induced AT group revealed 8 different and 2 similar recurrent ATs compared to the induced ATs at first session. The mean cycle length of induced AT that terminated by ablation (271 ± 64 ms) was longer than that without (249 ± 58 ms, P < 0.05). In induced AT group, AT recurrence rate in patients who achieved AT termination by ablation was lower than those without termination (5% vs 36%, P < 0.05). CONCLUSIONS: ATs that are inducible after LPAF termination do not necessarily become clinical AT. However, patients who achieved noninducibility of AT by ablating slower cycle length of AT had better outcomes.

Circadian and seasonal variations of ventricular tachyarrhythmias in patients with early repolarization syndrome and Brugada syndrome: analysis of patients with implantable cardioverter defibrillator.

INTRODUCTION: The circadian and seasonal patterns of ventricular tachyarrhythmia (VTA) in patients with early repolarization syndrome (ERS) have not been determined. We compared the timing of VTAs in patients with ERS and Brugada syndrome (BS). METHODS AND RESULTS: We enrolled patients with ERS (n = 14) and BS (n = 53) who underwent implantable cardioverter defibrillator (ICD) implantation. The timing of VTAs, including cardiac arrest and appropriate shocks, was determined. During follow up of 6.4 ± 3.6 years in the ERS group and 5.0 ± 3.3 years in the BS group, 5 of 14 (36%) ERS and 10 of 53 (19%) BS patients experienced appropriate shocks (P = 0.37). Cardiac arrest showed a trend of nocturnal distribution peaking from midnight to early morning (P = 0.14 in ERS, P = 0.16 in BS). Circadian distribution of appropriate shocks showed a significant nocturnal peak in patients with ERS (P < 0.0001) but a trend toward a nocturnal peak in patients with BS (P = 0.08). There were no seasonal differences in cardiac arrest in patients with ERS and BS. However, patients with ERS showed a seasonal peak in appropriate shocks from spring to summer (P < 0.0001). There was no significant seasonal peak in patients with BS. The timing of VTAs (cardiac arrest plus appropriate shock) showed significant nocturnal distributions in patients with ERS and BS (P < 0.01, respectively). A significant clustering of VTAs was noted from spring to summer (P < 0.01) in patients with ERS, but not in patients with BS (P = 0.42). CONCLUSIONS: Incidence of VTAs showed marked circadian variations with night-time peaks in patients with ERS and BS.

Catheter ablation of atrial fibrillation in patients with chronic lung disease.

BACKGROUND: Chronic lung disease (CLD) is one of the important underlying diseases of atrial fibrillation (AF). The outcomes after radiofrequency catheter ablation of AF in patients with CLD have not yet been reported. We investigated the electroanatomic alterations in pulmonary veins (PVs) in CLD patients with AF and assessed their effect on the outcomes of radiofrequency catheter ablation of AF. METHOD AND RESULTS: We assessed 15 patients who had CLD and underwent radiofrequency catheter ablation of AF. CLD included chronic obstructive pulmonary disease, a tuberculosis-destroyed lung, and interstitial lung disease. For controls, we selected 60 sex-, age-, and procedure era-matched non-CLD patients who received radiofrequency catheter ablation for AF (4 controls for each CLD patient). Eight patients had chronic obstructive pulmonary disease, 6 had a tuberculosis-destroyed lung, and 1 had interstitial lung disease. PV morphology in the affected lung was altered significantly, ie, obliteration, pulling of the PVs toward the destroyed lung, or compensatory bulging of the PV antrum. These alterations were related to arrhythmogenicity in 6 (40%) of 15 patients with CLD. Non-PV foci were more common in the CLD group (4/15, 26.7%) than in the control group (3/60, 5.0%; P=0.025). All non-PV foci were located in the right atrium. The AF recurrence rate in the CLD group (26.7%, 4/15) was similar to that in the control group (18.3%, 11/60; P=0.45). CONCLUSIONS: Significant alteration of PV anatomy was related to arrhythmogenicity, and non-PV foci from the right atrium were commonly observed in the CLD group. Radiofrequency catheter ablation can be performed safely for AF in CLD patients with a comparable success rate to that in patients with normal lungs.

Comparison of voltage map-guided left atrial anterior wall ablation versus left lateral mitral isthmus ablation in patients with persistent atrial fibrillation.

BACKGROUND: Left lateral mitral isthmus (LLMI) ablation achieves a low percentage of bidirectional conduction block in atrial fibrillation (AF) ablation. OBJECTIVE: The purpose of this study was to investigate whether linear ablation through the lowest voltage area on the left atrial anterior wall (LAAW) can lead to better clinical outcomes compared to LLMI ablation. METHODS: We obtained high-density three-dimensional (3D) voltage mapping (CARTO) of the LA in 29 patients with persistent AF and determined the area of low voltage. In the multicenter prospective study, clinical outcomes of LAAW (n = 100) and LLMI ablations (n = 100) were compared in patients with persistent AF (79.4% male, 59.4 ± 10.6 years). RESULTS: (1) The low-voltage area consistently existed on LAAW and had a correlation with the LA-aorta contact area (R = 0.921, P <.0001). Mean voltage of LAAW was significantly lower than that of LLMI (P <.0001). (2) The length of LAAW ablation (37.9 ± 3.4 mm vs 26.6 ± 3.2 mm, P <.0001) was longer, but achievement of bidirectional block was higher (68.0% vs 32.0%, P = .0001) than in LLMI ablation. Mean duration of LAAW and LLMI ablations was 19.3 ± 2.9 minutes and 18.2 ± 3.7 minutes, respectively (P = .086). (3) During follow-up of 23.3 ± 7.4 months, the recurrence rate of AF after LAAW ablation (26.0%) was significantly lower than that of LLMI ablation (41.0%, P = .021) after a single procedure. CONCLUSION: The voltage map is useful for guiding linear ablation in persistent AF patients. LAAW is the most frequent low-voltage area around the mitral annulus, and linear ablation along LAAW results in a better clinical outcome with a higher rate of bidirectional conduction block compared to LLMI ablation.

Role of residual potentials inside circumferential pulmonary veins ablation lines in the recurrence of paroxysmal atrial fibrillation.

BACKGROUND: Residual gaps due to incomplete ablation lines are known to be the most common cause of recurrent atrial fibrillation (AF) after catheter ablation. We hypothesized that any residual potentials at the junction of the left atrium and pulmonary vein (PV), inside the circumferential PV ablation (CPVA) lines, would contribute to the recurrence of AF or post-AF ablation atrial flutter (AFL); therefore, the elimination of these potentials increases AF-/AFL-free survival rates. METHODS AND RESULTS: One hundred and two patients with paroxysmal AF (PAF) were enrolled and prospectively randomized to a group with ablation of residual potentials as add-on therapy to CPVA + PV electrical isolation (PVI) (group 1, n = 49), or a group without ablation of the residual potentials (group 2, n = 53). Post-CPVA residual potentials, inside the ablation lines, were identified by contact bipolar electrode mapping catheter and a detailed 3-dimensional voltage map. Twenty-three patients in group 1 and 18 patients in group 2 had post-CPVA residual potentials (46.9% vs 34.0%, P = 0.182). The AF-/AFL-free survival rate during follow-up of 23.3 ± 7.9 months was not different in comparisons between the 2 groups (P = 0.818), and 79.6% and 81.1% of the patients in groups 1 and 2 maintained a sinus rhythm (P = 0.845), respectively. CONCLUSIONS: Residual potentials inside CPVA were commonly found in the patients with PAF after CPVA + PVI. Further ablation of residual potentials did not increase the efficacy of catheter ablation in patients with PAF.

Atrial activation time and pattern of linear triple-site vs. single-site atrial pacing after cardioversion in patients with atrial fibrillation.

AIMS: Multisite atrial pacing has been suggested to be effective in suppressing atrial fibrillation (AF), however, the effect of linear triple-site atrial pacing (LTSP) in humans has not been evaluated. We compared the effects of LTSP to single-site atrial pacing (SSP) on the atrial activation and wavefront propagation pattern in patients with persistent AF. METHODS AND RESULTS: In 10 patients with persistent AF, the effects of LTSP and SSP were evaluated by left atrial (LA) endocardial non-contact multielectrode array mapping and multipolar catheters. LTSP and SSP were delivered from the high right atrium (HRA), the distal coronary sinus (CS), and within the LA at the site showing maximal overlay of low-voltage zones during sinus rhythm and pacing at HRA and CS. Atrial activation time and pattern, P wave duration, and the prevention of AF induced by burst pacing were assessed with these pacing interventions. Compared with SSP, LTSP at the HRA, CS, and LA shortened atrial activation times (183 +/- 24 vs. 174 +/- 24 ms, 186 +/- 29 vs. 166 +/- 28 ms, and 171 +/- 40 vs. 163 +/- 39 ms; P < 0.05, respectively). P wave duration was shorter with LTSP than SSP at all three sites (141.7 +/- 35.1 vs. 146.9 +/- 38.5 ms, 138.1 +/- 34.6 vs. 145.7 +/- 33.7 ms, and 142.7 +/- 33.4 vs. 151.3 +/- 35.1 ms; P < 0.05, respectively). LTSP initially depolarized a larger area than SSP, and produced more uniform and planar wavefront propagation. LTSP prevented the burst-induction of AF during LA pacing in 3 of 10 patients, while SSP was never successful. CONCLUSION: In patients with persistent AF, LTSP provided more rapid and uniform activation of the atria compared with SSP, which was associated with prevention of burst-induction of AF in some patients. Further study is required to determine whether LTSP can modify the substrate of chronic AF, leading to frank AF suppression.