Lower contact force predicts right pulmonary vein carina breakthrough after ablation index-guided pulmonary vein isolation using high-power short-duration.

INTRODUCTION: Carina breakthrough (CB) at the right pulmonary vein (RPV) can occur after circumferential pulmonary vein isolation (PVI) due to epicardial bridging or transient tissue edema. High-power short-duration (HPSD) ablation may increase the incidence of RPV CB. Currently, the surrogate of ablation parameters to predict RPV CB is not well established. This study investigated predictors of RPV CB in patients undergoing ablation index (AI)-guided PVI with HPSD. METHODS: The study included 62 patients with symptomatic atrial fibrillation (AF) who underwent AI-guided PVI using HPSD. Patients were categorized into two groups based on the presence or absence of RPV CB. Lesions adjacent to the RPV carina were assessed, and CB was confirmed through residual voltage, low voltage along the ablation lesions, and activation wavefront propagation. RESULTS: Out of the 62 patients, 21 (33.87%) experienced RPV CB (Group 1), while 41 (66.13%) achieved first-pass RPV isolation (Group 2). Despite similar AI and HPSD, patients with RPV CB had lower contact force (CF) at lesions adjacent to the RPV carina. Receiver operating characteristic (ROC) curve analysis identified CF < 10.5 g as a predictor of RPV CB, with 75.7% sensitivity and 56.2% specificity (area under the curve: 0.714). CONCLUSION: In patients undergoing AI-guided PVI with HPSD, lower CF adjacent to the carina was associated with a higher risk of RPV CB. These findings suggest that maintaining higher CF during ablation in this region may reduce the occurrence of RPV CB.

Comparison of Long-Term Clinical Outcomes Between Segmental and Circumferential Pulmonary Vein Isolation in Patients Undergoing Repeat Atrial Fibrillation Ablation.

BACKGROUND: Circumferential pulmonary vein isolation (CPVI) has supplanted segmental PVI (SPVI) as standard procedure for atrial fibrillation (AF). However, there is limited evidence examining the efficacy of these strategies in redo ablations. In this study, we investigated the difference in recurrence rates between SPVI and CPVI in redo ablations for PV reconnection.Methods and Results: This study retrospectively enrolled 543 patients who had undergone AF ablation between 2015 and 2017. Among them, 167 patients (30.8%, including 128 male patients and 100 patients with paroxysmal AF) underwent redo ablation for recurrent AF. Excluding 26 patients without PV reconnection, 141 patients [90 patients of SPVI (Group 1) and 51 patients of CPVI (Group 2)] were included. The AF-free survival rates were 53.3% and 56.9% in Group 1 and Group 2, respectively (P=0.700). The atrial flutter (AFL)-free survival rates were 90% and 100% in Group 1 and Group 2, respectively (P=0.036). The ablation time was similar between groups, and there no major complications were observed. CONCLUSIONS: For redo AF ablation procedures, SPVI and CPVI showed similar outcomes, except for a higher AFL recurrence rate for SPVI after long-term follow-up (>2 years). This may be due to a higher probability of residual PV gaps causing reentrant AFL.

Fractal complexity alternations in paroxysmal atrial fibrillation patients with and without recurrence after pulmonary vein isolation.

BACKGROUND: Pulmonary vein isolation (PVI) is a cornerstone therapy for paroxysmal atrial fibrillation (PAF). The variations in nonlinear heart rate variability (HRV) between patients with and without recurrences remain unclear. We aimed to characterize the nonlinear HRV before and after PVI in patients with and without recurrence. METHODS: Twenty-five drug-refractory PAF patients (56.0 ± 9.1 years old, 20 males) who received PVI were enrolled. Holter electrocardiography were performed before, 1-3, and 6-12 months after PVI. After 8.2 ± 2.5 months of follow-ups after PVI, patients were divided into two groups: the recurrence (n = 8) and non-recurrence (n = 17) groups. Linear and nonlinear HRV variables were analyzed, including the Poincaré Plot analysis and the Detrended Fluctuation Analysis (DFA). RESULTS: The non-recurrence group, but not the recurrence group, had decreased high-frequency component (HF), the root mean square of successive RR interval differences (RMSSD), and the Poincaré Plot index SD1 1-3 months after PVI and increased DFAslope2 6-12 months after PVI. The non-recurrence group's LF/HF ratio and DFAslope1 decreased significantly 1-3 and 6-12 months after PVI, respectively, whereas there was no significant change in the recurrence group after PVI. CONCLUSIONS: Significantly reduced vagal tone 1-3 months after PVI, increased long-term fractal complexity 6-12 months after PVI, and decreased sympathetic tone as well as short-term fractal complexity 1-3 and 6-12 months after PVI led to a better AF-free survival after PVI. These findings suggest that neuromodulation and heart rate dynamics play crucial roles in AF recurrence following PVI.

Long-term mortality and cardiovascular outcomes in patients with atrial flutter after catheter ablation.

AIMS: For patients with typical and atypical atrial flutter (AFL) but without history of atrial fibrillation (AF), the long-term cardiovascular (CV) outcomes after catheter ablation for AFL remain unclear. We compared the long-term all-cause mortality and CV outcomes in patients with AFL receiving catheter ablation compared with the results with medical therapy. METHODS AND RESULTS: Atrial flutter patients receiving catheter ablation for typical AFL were identified using the Health Insurance Database, and constituted the 'AFL ablation group'. Patients with typical and atypical AFL but without ablation (AFL without ablation group) were propensity matched to the AFL ablation group. Patients with prior AF diagnosis were excluded. Primary outcomes included all-cause and CV mortality, heart failure (HF) hospitalization, and stroke. The multivariable cox hazards regression model was used to evaluate the hazard ratio (HR) for study outcomes. A total of 3784 AFL patients (1892 patients in each group) was studied. Their mean follow-up durations were 7.85 ± 2.57 years (AFL without ablation group) and 8.31 ± 4.53 years (AFL ablation group). Atrial flutter with ablation patients had lower risks of all-cause mortality (HR: 0.68, P < 0.001), CV deaths (HR: 0.78, P = 0.001), HF hospitalization (HR: 0.84, P = 0.01), and stroke (HR: 0.80, P = 0.01). CONCLUSIONS: Catheter ablation for AFL in patients without prior AF was associated with lower risks of all-cause mortality and CV events compared with AFL patients without ablation during long-term follow-ups.

Detecting supraventricular tachycardia with smartwatches facilitates the decision for catheter ablation: A case series.

Smartwatch allows easy detection of arrhythmia. Such an approach is widely used for detecting atrial fibrillation. However, there has been no consensus on the diagnostic power of smartwatch-detected supraventricular tachycardia (SVT). We reported three patients of SVT presenting with infrequent palpitations. Their SVTs were not documented with single-lead or standard ECG in hospital before, but only recorded by the single-lead ECG on smartwatches. Electrophysiological studies confirmed the mechanisms of these SVTs and led to successful catheter ablations. In conclusion, in patients with recurrent symptomatic tachycardia and a smartwatch-detected SVT, an electrophysiological study is indicated rather than to wait for a standard ECG for clinical decision. This approach might prevent the delay for successful treatment.

Hyperuricemia and diabetes mellitus when occurred together have higher risks than alone on all-cause mortality and end-stage renal disease in patients with chronic kidney disease.

INTRODUCTION: Hyperuricemia and diabetes mellitus (DM) are associated with increased mortality risk in patients with chronic kidney disease (CKD). Here we aimed to evaluate the independent and joint risks of these two conditions on mortality and end stage kidney disease (ESKD) in CKD-patients. METHODS: This retrospective cohort study enrolled 4380 outpatients (with CKD stage 3-5) with mortality and ESKD linkage during a 7-year period (from 2007 to 2013). All-causes mortality and ESKD risks were analyzed by multivariable-adjusted Cox proportional hazards models (adjusted for age, sex, smoke, previous coronary arterial disease, blood pressure, and medications for hyperlipidemia, hyperuricemia and renin-angiotensin system inhibitors). RESULTS: Overall, 40.5% of participants had DM and 66.4% had hyperuricemia. In total, 356 deaths and 932 ESKD events occurred during the 7 years follow-up. With the multivariate analysis, increased risks for all-cause mortality were: hyperuricemia alone, HR = 1.48 (1-2.19); DM alone, and HR = 1.52 (1.02-2.46); DM and hyperuricemia together, HR = 2.12 (1.41-3.19). Similar risks for ESKD were: hyperuricemia alone, HR = 1.34 (1.03-1.73); DM alone, HR = 1.59 (1.15-2.2); DM and hyperuricemia together, HR = 2.46 (1.87-3.22). CONCLUSIONS: DM and hyperuricemia are strongly associated with higher all-cause mortality and ESKD risk in patients with CKD stage 3-5. Hyperuricemia is similar to DM in terms of risk for all-cause mortality and ESKD. DM and hyperuricemia when occurred together further increase both risks of all-cause mortality and ESKD.

Risks of Ventricular Tachyarrhythmia and Mortality in Patients with Amyloidosis - A Long-Term Cohort Study.

Background: The presence of ventricular tachycardia (VT) is associated with higher mortality. The annual incidence of VT after a diagnosis of amyloidosis and the associated cardiovascular (CV) outcomes have not been well assessed in a large cohort. Methods: A total of 12,139 amyloidosis patients were identified from the Taiwan National Health Insurance Research Database. Non-amyloidosis group was matched 1:1 for age, gender, hypertension, and diabetes mellitus (DM) to the amyloidosis group using a propensity score. Analysis of the risk of CV outcomes was conducted. We also analyzed the incidence of cardiac amyloidosis (CA). Results: The incidence rates of amyloidosis and CA were 6.54 and 0.61 per 100,000 person-years, respectively. Multivariable analysis revealed that the risk of VT was higher in both the amyloidosis [hazard ratio (HR): 7.90; 95% confidence interval (CI): 4.49-13.9] and CA (HR: 153.3, 95% CI: 54.3-432.7) groups. In the amyloidosis group, the risk of heart failure (HF)-related hospitalization, CV death, and all-cause death was also higher. Amyloidosis was associated with a higher CV mortality rate following VT (HR: 1.50; 95% CI: 1.07-2.12). The onset of a new VT event in patients with amyloidosis was associated with HF, DM, chronic liver disease, and anti-arrhythmic drug use. Conclusions: In this nationwide cohort study, the incidence rates of amyloidosis and CA were 6.54 and 0.61 per 100,000 person-years, respectively. The long-term risks of VT and CV mortality were higher in the patients with amyloidosis and CA. The patients with amyloidosis had a poorer prognosis following VT events, highlighting the importance of continuous monitoring in these patients.

Hypoglycaemic episodes increase the risk of ventricular arrhythmia and sudden cardiac arrest in patients with type 2 diabetes-A nationwide cohort study.

BACKGROUND: The impact of hypoglycaemic episode (HE) on the risk of ventricular arrhythmia (VA) and sudden cardiac arrest (SCA) remains unclear. We hypothesized that HE increases the risk of both VA and SCA and that glucose-lowering agents causing HE also increase the risk of VA/SCA in patients with type 2 diabetes (T2D). METHODS: Patients aged 20 years or older with newly diagnosed T2D were identified using the Taiwan National Health Insurance Database. HE was defined as the presentation of hypoglycaemic coma or specified/unspecified hypoglycaemia. The control group consisted of T2D patients without HE. The primary outcome was the occurrence of VA (including ventricular tachycardia and fibrillation) and SCA during the defined follow-up periods. A multivariate Cox hazards regression model was used to evaluate the hazard ratio (HR) for VA or SCA. RESULTS: A total of 54 303 patients were screened, with 1037 patients with HE assigned to the HE group and 4148 frequency-matched patients without HE constituting the control group. During a mean follow-up period of 3.3 ± 2.5 years, 29 VA/SCA events occurred. Compared with the control group, HE group had a higher incidence of VA/SCA (adjusted HR: 2.42, P = .04). Patients who had used insulin for glycaemic control showed an increased risk of VA/SCA compared with patients who did not receive insulin (adjusted HR: 3.05, P = .01). CONCLUSIONS: The HEs in patients with T2D increased the risk of VA/SCA, compared with those who did not experience HEs. Use of insulin also independently increased the risk of VA/SCA.

Glitazones and alpha-glucosidase inhibitors as the second-line oral anti-diabetic agents added to metformin reduce cardiovascular risk in Type 2 diabetes patients: a nationwide cohort observational study.

OBJECTIVE: Metformin is the standard first-line drug for patients with Type 2 diabetes (T2DM). However, the optimal second-line oral anti-diabetic agent (ADA) remains unclear. We investigated the cardiovascular risk of various ADAs used as add-on medication to metformin in T2DM patients from a nationwide cohort. METHODS: T2DM patients using different add-on oral ADAs after an initial metformin therapy of > 90 days were identified from the Taiwan National Health Insurance Database. Five classes of ADAs, including sulphonylureas (SU), glinides, thiazolidinediones (TZD), alpha-glucosidase inhibitors (AGI), and dipeptidyl peptidase-4 inhibitors (DPP-4I) were selected for analysis. The reference group was the SU added to metformin. Patients were excluded if aged < 20 years, had a history of stroke or acute coronary syndrome (ACS), or were receiving insulin treatment. The primary outcomes included any major adverse cardiovascular event (MACE) including ACS, ischemic/hemorrhagic stroke, and death. A Cox regression model was used to estimate the hazard ratio (HR) for MACE. RESULTS: A total of 26,742 patients receiving their add-on drug to metformin of either SU (n = 24,277), glinides (n = 962), TZD (n = 581), AGI (n = 808), or DPP-4I (n = 114) were analyzed. After a mean follow-up duration of 6.6 ± 3.4 years, a total of 4775 MACEs occurred. Compared with the SU+metformin group (reference), the TZD+metformin (adjusted HR: 0.66; 95% CI 0.50-0.88, p = 0.004) and AGI+metformin (adjusted HR: 0.74; 95% CI 0.59-0.94, p = 0.01) groups showed a significantly lower risk of MACE. CONCLUSION: Both TZD and AGI, when used as an add-on drug to metformin were associated with lower MACE risk when compared with SU added to metformin in this retrospective cohort study. Trial registration CE13152B-3. Registered 7 Mar, 2013, retrospectively registered.

Heterogeneous distribution of substrates between the endocardium and epicardium promotes ventricular fibrillation in arrhythmogenic right ventricular dysplasia/cardiomyopathy.

Aims: Whether the distribution of scar in arrhythmogenic right ventricular cardiomyopathy (ARVC) plays a role in predicting different types of ventricular arrhythmias is unknown. This study aimed to investigate the prognostic value of scar distribution in patients with ARVC. Methods and results: We studied 80 consecutive ARVC patients (46 men, mean age 47 ± 15 years) who underwent an electrophysiological study with ablation. Thirty-four patients receive both endocardial and epicardial mapping. Abnormal endocardial substrates and epicardial substrates were characterized. Three groups were defined according to the epicardial and endocardial scar gradient (<10%: transmural, 10-20%: intermediate, >20%: horizontal, as groups 1, 2, and 3, respectively). Sinus rhythm electrograms underwent a Hilbert-Huang spectral analysis and were displayed as 3D Simultaneous Amplitude Frequency Electrogram Transformation (SAFE-T) maps, which represented the arrhythmogenic potentials. The baseline characteristics were similar between the three groups. Group 3 patients had a higher incidence of fatal ventricular arrhythmias requiring defibrillation and cardiac arrest during the initial presentation despite having fewer premature ventricular complexes. A larger area of arrhythmogenic potentials in the epicardium was observed in patients with horizontal scar. The epicardial-endocardial scar gradient was independently associated with the occurrence of fatal ventricular arrhythmias after a multivariate adjustment. The total, ventricular tachycardia, and VF recurrent rates were higher in Group 3 during 38 ± 21 months of follow-up. Conclusion: For ARVC, the epicardial substrate that extended in the horizontal plane rather than transmurally provided the arrhythmogenic substrate for a fatal ventricular arrhythmia circuit.

Association of Single Nucleotide Polymorphisms with Atrial Fibrillation and the Outcome after Catheter Ablation.

BACKGROUND: The association of gene variants with atrial fibrillation (AF) type and the recurrence of AF after catheter ablation in Taiwan is still unclear. In this study, we aimed to investigate the relationships between gene variants, AF type, and the recurrence of AF. METHODS: In our investigation, we examined 383 consecutive patients with AF (61.9 ± 14.0 years; 63% men); of these 383 patients, 189 underwent catheter ablation for drug-refractory AF. Thereafter, the single nucleotide polymorphisms rs2200733, and rs7193343 were genotyped using real-time polymerase chain reaction. RESULTS: The rs7193343 variant was independently associated with non-paroxysmal AF (non-PAF). In the PAF group, the rs7193343 variant was independently associated with AF recurrence after catheter ablation. However, the rs2200733 variant was not associated with AF recurrence in this group. The combination of the rs7193343 and rs2200733 risk alleles was associated with a better predictive power in the PAF patients. In contrast, in the non-PAF group, the SNPs were not associated with recurrence. The rs7193343 and rs2200733 variants were not associated with different atrial voltage and activation times. CONCLUSIONS: The rs7193343 variants were associated with AF recurrence after catheter ablation in PAF patients but not in non-PAF patients. The rs7193343 CC variant was independently associated with non-PAF.

A prospective and randomized comparison of limited versus extensive atrial substrate modification after circumferential pulmonary vein isolation in nonparoxysmal atrial fibrillation.

INTRODUCTION: The optimal substrate ablation approach in patients with persistent atrial fibrillation (Per AF) remains unclear. This was a prospective randomized study comparing the efficacy of limited (continuous complex fractionated atrial electrogram, CFAE: <60 milliseconds) versus extensive (continuous CFAE plus variable CFAE: <120 milliseconds) atrial substrate modification in Per AF patients. METHODS AND RESULTS: We enrolled 120 Per AF patients in the study, and 30 patients with AF termination after pulmonary vein isolation (PVI) were excluded. In the remaining 90 patients, 45 were treated with limited approach (Group 1) and 45 with an extensive approach (Group 2). The end point of the study was the incidence of an atrial arrhythmia recurrence postblanking period. The patients were followed up for 15 months with 3-month clinical reviews, electrograms (ECGs), Holter recordings, and echocardiographic monitoring. Procedural AF termination and the single procedural efficacy were statistically comparable between the 2 groups (48.9% vs. 63.4% in Groups 1 and 2, respectively, P = 0.289). During the follow-up, patients who received limited ablation had a lower incidence of recurrent AFL (P = 0.04), and better reverse remodeling of the left atrium (LA, P = 0.04). After 2 procedures, the freedom from any atrial arrhythmia was better in Group 2 (62.2% vs. 87.8%, P = 0.009). Those with longstanding AF and a larger baseline LA size responded better to the extensive ablation. CONCLUSIONS: In the Per AF patients who failed to achieve AF termination after PVI alone, a specific atrial substrate modification approach targeting only continuous CFAEs could be considered as an initial ablation strategy.

Skin sympathetic nerve activity in different ablation settings for atrial fibrillation.

BACKGROUND: Modifying the autonomic system after catheter ablation may prevent the recurrence of atrial fibrillation (AF). Evaluation of skin sympathetic nerve activity (SKNA) is a noninvasive method for the assessment of sympathetic activity. However, there are few studies on the effects of different energy settings on SKNA. OBJECTIVE: To investigate the changes in SKNA in different energy settings and their relationship to AF ablation outcomes. METHODS: Seventy-two patients with paroxysmal and persistent AF were enrolled. Forty-three patients received AF ablation with the conventional (ConV) energy setting (low power for long duration), and 29 patients using a high-power, short-duration (HPSD) strategy. The SKNA was acquired from the right arm 1 day before and after the radiofrequency ablation. We analyzed the SKNA and ablation outcomes in the different energy settings. RESULTS: Both groups had a similar baseline average SKNA (aSKNA). We found that the median aSKNA increased significantly from 446.82 µV to 805.93 µV (p = 0.003) in the ConV group but not in the HPSD group. In the ConV group, patients without AF recurrence had higher aSKNA values. However, the 1-year AF recurrence rate remained similar between both groups (35 % vs. 28 %, p = 0.52). CONCLUSION: The post-ablation aSKNA levels increased significantly in the ConV group but did not change significantly in the HPSD group, which may reflect different neuromodulatory effects. However, the one-year AF recurrence rates were similar for both groups. These results demonstrate that the HPSD strategy has durable lesion creation but less lesion depth, which may reduce collateral damage.

Differences in the atrial electrophysiological properties between vagal and sympathetic types of atrial fibrillation.

INTRODUCTION: Autonomic modulation of the cardiac activity plays an important role in the pathogenesis of atrial fibrillation (AF). The aim of this study was to assess the differences in the atrial electrical and structural properties between patients with vagal and sympathetic AF. METHODS: The study included 30 patients (53 ± 12 years old, male 26) with frequent attacks of symptomatic paroxysmal AF. All cases underwent 24-hour ambulatory Holter monitoring before the catheter ablation. The onset of AF accompanied with an increased HF component and decreased L/H ratio was designated as a vagal type (group 1, n = 12), whereas a decreased HF component and increased L/H ratio was classified as a sympathetic type (group 2, n = 18). Electrical and structural properties were evaluated during the ablation procedure. RESULTS: All patients had AF originating from PVs. There was a higher incidence of non-PV triggers in group 2 patients than that in group 1 (44% vs 8%, P = 0.04). Group 1 had a higher bipolar peak-to-peak voltage and mean DF of the global left atrium (LA), shorter total activation time, and smaller LA volume than group 2, whereas the electrical and structural properties in the right atrium were similar. After a follow-up of 15 ± 7 months, there was a lower incidence of AF recurrence in group 1 than that in group 2 (0% vs 28%, P = 0.02). CONCLUSION: There are better electrical properties and a smaller LA volume in patients with vagal-type AF. In contrast, the LA substrate is worse, and coexisting non-PV triggers and recurrence following ablation are more prevalent in patients with the sympathetic-type AF.

Prolonged atrium electromechanical interval is associated with stroke in patients with atrial fibrillation after catheter ablation.

INTRODUCTION: Atrial fibrillation (AF) is associated with increased risk of embolic stroke. Catheter ablation of AF provides an effective therapy for patients with symptomatic and drug-refractory AF. The aim of this study was to evaluate whether the atrial electromechanical interval is useful in identifying patients at risk of stroke after successful catheter ablation. METHODS AND RESULTS: A total of 279 AF patients who received catheter ablation and showed no evidence of recurrences were enrolled. Electromechanical interval (PA-PDI) was determined as the time interval from the initiation of P wave deflection to the peak of mitral inflow A wave on pulse wave Doppler imaging. The PA-PDI interval was measured for each patient after the 3-month blanking period of catheter ablation. The clinical endpoint was the occurrence of ischemic stroke. During the follow-up of 46.5 ± 17.2 months, 6 patients suffered from ischemic strokes. Patients with strokes had higher CHA2DS2-VASc scores and longer PA-PDI intervals (138.7 ± 12.4 ms vs 161.2 ± 7.7 ms, P value < 0.001) compared to those without strokes. At a cutoff point of 150 ms identified by ROC curve, the positive and negative predictive values of the PA-PDI interval to predict stroke were 86.7% and 100%, respectively. The PA-PDI interval improved the predictive performance of the CHA2DS2-VASc score, and the area under the ROC curve increased from 0.75 to 0.85. CONCLUSIONS: Our results suggest that the PA-PDI interval is a useful tool to identify patients with high risk of stroke after successful catheter ablation of AF.

Nonlinear analysis of fibrillatory electrogram similarity to optimize the detection of complex fractionated electrograms during persistent atrial fibrillation.

INTRODUCTION: Currently, the identification of complex fractionated atrial electrograms (CFEs) in the substrate modification is mostly based on cycle length-derived algorithms. The characteristics of the fibrillation electrogram morphology and their consistency over time are not clear. The aim of this study was to optimize the detection algorithm of crucial CFEs by using nonlinear measure electrogram similarity. METHODS AND RESULTS: One hundred persistent atrial fibrillation patients that underwent catheter ablation were included. In patients who required CFE ablation (79%), the time-domain fibrillation signals (6 seconds) were acquired for a linear analysis (mean fractionation interval and dominant frequency [DF]) and nonlinear-based waveform similarity analysis of the local electrograms, termed the similarity index (SI). Continuous CFEs were targeted with an endpoint of termination. Predictors of the various signal characteristics on the termination and clinical outcome were investigated. Procedural termination was observed in 39% and long-term sinus rhythm maintenance in 67% of the patients. The targeted CFEs didn't differ based on the linear analysis modalities between the patients who responded and did not respond to CFE ablation. In contrast, the average SI of the targeted CFEs was higher in termination patients, and they had a better outcome. Multivariate regression analysis showed that a higher SI independently predicted sites of termination (≥ 0.57; OR = 4.9; 95% CI = 1.33-18.0; P = 0.017). CONCLUSIONS: In persistent AF patients, a cycle length-based linear analysis could not differentiate culprit CFEs from bystanders. This study suggested that sites with a high level of fibrillation electrogram similarity at the CFE sites were important for AF maintenance.

Long-term outcome of catheter ablation in patients with atrial fibrillation originating from nonpulmonary vein ectopy.

INTRODUCTION: Data regarding the long-term outcome of catheter ablation in patients with nonpulmonary vein (NPV) ectopy initiating atrial fibrillation (AF) are limited. We aimed to evaluate the long-term result of patients with AF who had NPV triggers and underwent catheter ablation. METHODS AND RESULTS: The study included 660 consecutive patients (age 54 ± 11 years old, 477 males) who had undergone catheter ablation for AF. Group 1 consisted of 132 patients with AF initiating from the NPV, and group 2 consisted of 528 patients with AF initiating from pulmonary vein (PV) triggers only. Patients from Group 1 were younger than those from Group 2 (51 ± 12 years old vs 54 ± 11 years old, P = 0.001) and were more likely to be females (34.4% vs 25.8%, P = 0.049). The incidences of nonparoxysmal AF (36.4% vs 16.3%, P < 0.001) and right atrial (RA) enlargement (31.3% vs 19%, P = 0.004) were higher, and the biatrial substrates were worse in Group 1 than those in Group 2 (left atrial voltage 1.5 ± 0.7 mV vs 1.9 ± 0.7 mV, P < 0.001, RA voltage 1.6 ± 0.5 mV vs 1.8 ± 0.6 mV, P = 0.014). During a follow-up period of 46 ± 23 months, there was a higher AF recurrence rate in Group 1 than in Group 2 (57.6% vs 38.8%, P < 0.001). The independent predictors of AF recurrence were NPV trigger (P < 0.001, HR 2, 95% CI 1.4-2.85), nonparoxysmal AF (P = 0.021, HR 1.55, 95% CI 1.07-2.24), larger left atrial diameter (P = 0.002, HR 1.04, 95% CI 1.02-1.07) and worse left atrial substrate (P = 0.028, HR 1.3, 95% CI 1.03-1.64). CONCLUSION: Compared to AF originating from the PV alone, AF originating from the NPV ectopy showed a worse outcome.

Sinus node dysfunction in atrial fibrillation patients: the evidence of regional atrial substrate remodelling.

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.