The Clinical Application of the Deep Learning Technique for Predicting Trigger Origins in Patients With Paroxysmal Atrial Fibrillation With Catheter Ablation

Background:

Non–pulmonary vein (NPV) trigger has been reported as an important predictor of recurrence post–atrial fibrillation ablation. Elimination of NPV triggers can reduce the recurrence of postablation atrial fibrillation. Deep learning was applied to preablation pulmonary vein computed tomography geometric slices to create a prediction model for NPV triggers in patients with paroxysmal atrial fibrillation.

Methods:

We retrospectively analyzed 521 patients with paroxysmal atrial fibrillation who underwent catheter ablation of paroxysmal atrial fibrillation. Among them, pulmonary vein computed tomography geometric slices from 358 patients with nonrecurrent atrial fibrillation (1–3 mm interspace per slice, 20–200 slices for each patient, ranging from the upper border of the left atrium to the bottom of the heart, for a total of 23 683 images of slices) were used in the deep learning process, the ResNet34 of the neural network, to create the prediction model of the NPV trigger. There were 298 (83.2%) patients with only pulmonary vein triggers and 60 (16.8%) patients with NPV triggers±pulmonary vein triggers. The patients were randomly assigned to either training, validation, or test groups, and their data were allocated according to those sets. The image datasets were split into training (n=17 340), validation (n=3491), and testing (n=2852) groups, which had completely independent sets of patients.

Results:

The accuracy of prediction in each pulmonary vein computed tomography image for NPV trigger was up to 82.4±2.0%. The sensitivity and specificity were 64.3±5.4% and 88.4±1.9%, respectively. For each patient, the accuracy of prediction for a NPV trigger was 88.6±2.3%. The sensitivity and specificity were 75.0±5.8% and 95.7±1.8%, respectively. The area under the curve for each image and patient were 0.82±0.01 and 0.88±0.07, respectively.

Conclusions:

The deep learning model using preablation pulmonary vein computed tomography can be applied to predict the trigger origins in patients with paroxysmal atrial fibrillation receiving catheter ablation. The application of this model may identify patients with a high risk of NPV trigger before ablation.

Precordial T-Wave Inversions in Patients with Arrhythmogenic Right Ventricular Cardiomyopathy Who Present with the Initial Features of Right Ventricular Outflow Tract Arrhythmia

BACKGROUND

Precordial T-wave inversion (TWI) is an important diagnostic criterion for arrhythmogenic right ventricular cardiomyopathy (ARVC).

OBJECTIVE

This study aimed to characterize the initial repolarization features of definite ARVC in patients who first presented with right ventricular outflow tract ventricular arrhythmia (RVOT-VA) and TWI.

METHODS

Patients who presented with RVOT-VA and TWI ≥ V₂ were retrospectively assessed. The initial characteristics of repolarization between patients with and without a final diagnosis of definite ARVC during follow-up were compared.

RESULTS

TWI ≥ V₂ was observed in 61 of 553 patients (mean age: 44.1 ± 14.7 years; 14 men) with RVOT-VAs. After an average follow-up time of 54.9 ± 33.7 months, 31 (50.8%) patients were classified into the definite ARVC group and 30 (49.2%) into the non-definite ARVC group. The disappearance of precordial TWI ≥ V₂ was observed in eight (13.1%) patients after the elimination of RVOT-VAs. In a multivariate analysis of the initial electrocardiogram features, only fragmented QRS [odds ratio (OR): 15.45, 95% confidence interval (CI): 1.61-148.26, p = 0.02] and precordial V₂ TpTe interval (OR: 1.03, 95% CI: 1.01-1.06, p = 0.02) could independently predict definite ARVC during longitudinal follow-up. An initial V₂ TpTe cutoff value > 88.5 ms could predict the final diagnosis of definite ARVC, with a sensitivity and specificity of 74.2% and 78.6%, respectively.

CONCLUSIONS

Despite the high risk of ARVC in RVOT-VAs and TWI ≥ V₂, "normalization" of TWI was observed after ventricular arrhythmia elimination in 13.1% of the patients. Fragmented QRS and longer V₂ TpTe interval were associated with definite ARVC during longitudinal follow-up.

The application of novel segmentation software to create left atrial geometry for atrial fibrillation ablation: The implication of spatial resolution

BACKGROUND

The application of new imaging software for the reconstruction of left atrium (LA) geometry during atrial fibrillation (AF) ablation has not been well investigated.

METHODS

A total of 27 patients undergoing AF ablation using a CARTO Segmentation Module system were studied (phase I). High-density LA mapping using PentaRay was merged with computed tomography-based geometry from the auto-segmentation module. The spatial distortion between the two LA geometries was analyzed and compared using Registration Match View. The associated contact force on the two LA shells was prospectively validated in 16 AF patients (phase II).

RESULTS

Of the five LA regions, the roof area had the highest quality score between the two LA shells (1.7 ± 0.6). In addition, among the pulmonary veins (PVs), higher quality scores were observed in bilateral PV carinas (both 1.8 ± 0.1, p < 0.05) than in the anterior or posterior PV regions. Furthermore, surrounding the PV ostium, the on-surface points had a significantly higher contact force when targeting the high-density fast anatomical mapping shell than for the auto-segmentation module (right superior pulmonary vein, 20.7 ± 5.8 g vs 12.5 ± 4.4 g; right inferior pulmonary vein, 19.3 ± 6.8 g vs 11.8 ± 4.8 g; left superior pulmonary vein, 22.5 ± 7.3 g vs 11.2 ± 4.5 g; left inferior pulmonary vein, 15.7 ± 6.9 g vs 9.7 ± 4.4 g, p < 0.05 for each group).

CONCLUSION

The CARTO Segmentation Module and Registration Match View provide better anatomic accuracy and less regional distortion of the LA geometry, and this can prevent excessive contact and potential procedural complications.

Applying the CHA2DS2-VASc score to predict the risk of future acute coronary syndrome in patients receiving catheter ablation for atrial fibrillation

•

AF patients without catheter ablation have a higher risk of future ACS when compared to normal control group.

•

The presence of AF without catheter ablation is an independent risk factor for future acute coronary events.

•

Catheter ablation to AF could reduce future risk of acute coronary events over a very long-term follow-up.

•

The cut-off value of baseline CHA₂DS₂-VASc score ≥ 4 can strongly predict future acute coronary events in patients with AF.

Objective

It remains unknown whether catheter ablation for atrial fibrillation (AF) reduces future acute coronary syndrome (ACS) risk or whether the CHA₂DS₂-VASc score has a role in predicting this risk. We aimed to compare very long-term risk of ACS between patients who received catheter ablation to AF or antiarrhythmic medications and controls without AF.

Methods

Propensity scores were calculated for each patient and used to assemble a cohort of 787 patients undergoing AF ablation in 2003–2012. Patients were compared to an equal number of AF patients treated with antiarrhythmic medications and a control group without AF. Patients with previous coronary events were excluded. The primary endpoint was ACS occurrence.

Results

Baseline clinical characteristics were comparable. After a mean 9.1 ± 3.2-year follow-up, the ablation group had lower incidence of new onset ACS than the medication and non-AF control groups (annual incidence: 0.15%. 0.78%, and 0.35%; with 2.67, 4.16, and 10.44 cases/1000 person-years, respectively; P < 0.001). After adjusting for multiple confounders, the ablation group had lower future ACS risk than the medication (hazard ratio [HR]: 0.20, 95% confidence interval [CI]: 0.13–0.30) and control groups (HR: 0.30, 95% CI: 0.20–0.45). The CHA₂DS₂-VASc score was a strong predictor of ACS (HR: 1.61, 95% CI: 1.47–1.76; AUC: 85.9%, 95% CI: 78.5–93.2%). A baseline CHA₂DS₂-VASc score ≥ 4 predicted future ACS (positive predictive rate: 14.3%).

Conclusions

This study suggested that catheter ablation for AF may be beneficial to reduce future ACS risk in AF patients, and a high baseline CHA₂DS₂-VASc score can predict future acute coronary events.

Association of Ischemic Stroke, Major Bleeding, and Other Adverse Events With Warfarin Use vs Non-vitamin K Antagonist Oral Anticoagulant Use in Patients With Atrial Fibrillation With a History of Intracranial Hemorrhage

IMPORTANCE

Current guidelines recommend the use of non-vitamin K antagonist oral anticoagulants (NOACs) for stroke prevention in patients with atrial fibrillation (AF). Data regarding warfarin sodium use compared with NOAC use in patients with AF with a history of intracranial hemorrhage (ICH) are limited.

OBJECTIVE

To compare the clinical outcomes of warfarin use and NOAC use in patients with AF with a history of ICH using a nationwide cohort with AF.

DESIGN, SETTING, AND PARTICIPANTS

A nationwide cohort study from January 1, 2012, to December 31, 2016, was performed using data from the Taiwan National Health Insurance Research Database. The dates of analysis were July 1 to September 1, 2019. The study population comprised patients with AF with a history of ICH and a CHA2DS2-VASc score (congestive heart failure, hypertension, age ≥75 years [doubled], diabetes, prior stroke/transient ischemic attack/thromboembolism [doubled], vascular disease [prior myocardial infarction, peripheral artery disease], age 65-74 years, sex category [female]) of at least 1 for men or at least 2 for women who had received warfarin or NOACs. The clinical outcomes were examined using Cox proportional hazards regression analyses among the study population before and after propensity score matching.

EXPOSURES

Oral anticoagulation with warfarin or NOACs.

MAIN OUTCOMES AND MEASURES

The clinical outcomes measured were all-cause mortality, ischemic stroke, ICH, major bleeding, and adverse events.

RESULTS

The study cohort included 4540 patients (mean [SD] age, 76.0 [10.5] years; 2653 men [58.4%]), with 1047 patients receiving warfarin (mean [SD] age, 75.1 [11.4] years; 571 men [54.5%]) and 3493 patients receiving NOACs (mean [SD] age, 76.3 [10.2] years; 2082 men [59.6%]). Compared with warfarin use, NOAC use was associated with statistically significantly lower risk of all-cause mortality (adjusted hazard ratio [aHR], 0.517; 95% CI, 0.457-0.585), ICH (aHR, 0.556; 95% CI, 0.389-0.796), and major bleeding (aHR, 0.645; 95% CI, 0.525-0.793), whereas the rate of ischemic stroke was similar in the 2 groups (aHR, 0.879; 95% CI, 0.678-1.141). These results were generally consistent after propensity score matching among 973 patients in each group.

CONCLUSIONS AND RELEVANCE

Among patients with AF with prior ICH, NOAC use was associated with lower rates of ICH and major bleeding compared with warfarin use, whereas the rate of ischemic stroke was similar in the 2 groups. Among patients with AF with prior ICH, NOACs could be the preferred choice for stroke prevention.

Resistin as a Biomarker for the Prediction of Left Atrial Substrate and Recurrence in Patients with Drug-Refractory Atrial Fibrillation Undergoing Catheter Ablation

Resistin is an adipocytokine that is abundantly secreted from lipid cells and is related to the inflammatory process and cardiometabolic diseases. This study aimed to examine the role of resistin on inflammation and its effect on the clinical outcome of patients with atrial fibrillation (AF) following catheter ablation.A total of 108 patients (56.9 ± 12.0 years, 76.8% male) with symptomatic and drug-refractory AF undergoing catheter ablation were enrolled. Inflammatory biomarkers and epicardial fat volume by contrast computed tomography (CT) images were assessed in all patients before the procedure. Baseline resistin correlated with epicardial fat volume, tumor necrosis factor-α (TNF-α), and left atrial (LA) scar area. After the index procedure, the univariate analysis revealed that hypertension, persistent AF, LA diameter, and plasma resistin level were related to recurrent atrial arrhythmia. Multivariate regression analysis revealed that persistent AF, LA diameter, and plasma resistin level all independently predicted recurrent atrial arrhythmia after ablation. Plasma resistin with a level higher than 777 (pg/mL) could predict recurrence following catheter ablation of AF.High plasma resistin level is associated with poor left atrial substrate, high epicardial fat volume, and elevated TNF-α level in patients with AF. Plasma resistin may predict the recurrence of atrial arrhythmia after ablation.

Extremely late recurrences (≥3 years) of atrioventricular nodal reentrant tachycardia: Electrophysiological characteristics of the index and repeat ablation procedures

BACKGROUND

Catheter ablation is an effective treatment for atrioventricular nodal reentrant tachycardia (AVNRT). However, the characteristics of extremely late (>3 years) recurrences of AVNRT after a successful initial ablation are not fully elucidated. We aimed to explore the electrophysiological characteristics of extremely late recurrences of AVNRT after a successful ablation.

METHODS

From 1991 to 2018, 3311 patients (mean age: 48.7 ± 17.4 years; men: 1328 [40.1%]) who underwent catheter ablation for AVNRT were investigated. Baseline characteristics of the patients, recurrence status, and detailed electrophysiological parameters of the index and repeat ablation procedures were obtained for analysis.

RESULTS

After a mean follow-up period of 129.5 ± 58.0 months, 65 (2.0%) patients underwent repeat ablation for recurrences of AVNRT, of whom 17 (0.5%) presented with extremely late recurrences. The incidence of transient AV block was significantly higher in patients with extremely late recurrences (5.9%) than in those without recurrences (1.9%) but lower than that in patients with recurrences within <3 years (12.5%, P < .001). In addition, among patients with extremely late recurrences of AVNRT, the atrial-His bundle interval was significantly longer (99.1 ± 23.4 vs. 76.5 ± 13.1 ms, P < .01) and the need for intravenous isoproterenol and/or atropine for the induction of AVNRT (88.2% vs. 47.1%, P = .03) was higher in the repeat ablation procedure than in the index ablation procedure.

CONCLUSION

Recurrences of AVNRT can occur 3 years after a successful initial ablation. The electrophysiological features of the index and repeat ablation procedures differed between patients with extremely late recurrences of AVNRT and those with recurrences within <3 years.

Identification of critical isthmus using coherent mapping in patients with scar-related atrial tachycardia

INTRODUCTION

Accurate identification of slow conducting regions in patients with scar-related atrial tachycardia (AT) is difficult using conventional electrogram annotation for cardiac electroanatomic mapping (EAM). Estimating delays between neighboring mapping sites is a potential option for activation map computation. We describe our initial experience with CARTO 3 Coherent Mapping (Biosense Webster Inc,) in the ablation of complex ATs.

METHODS

Twenty patients (58 ± 10 y/o, 15 males) with complex ATs were included. We created three-dimensional EAMs using CARTO 3 system with CONFIDENSE and a high-resolution mapping catheter (Biosense Webster Inc). Local activation time and coherent maps were used to aid in the identification of conduction isthmus (CI) and focal origin sites. System-defined slow or nonconducting zones and CI, defined by concealed entrainment (postpacing interval < 20 ms), CV < 0.3 m/s and local fractionated electrograms were evaluated.

RESULTS

Twenty-six complex ATs were mapped (mean: 1.3 ± 0.7 maps/pt; 4 focal, 22 isthmus-dependent). Coherent mapping was better in identifying CI/breakout sites where ablation terminated the tachycardia (96.2% vs 69.2%; P = .010) and identified significantly more CI (mean/chamber 2.0 ± 1.1 vs 1.0 ± 0.7; P < .001) with narrower width (19.8 ± 10.5 vs 43.0 ± 23.9 mm; P < .001) than conventional mapping. Ablation at origin and CI sites was successful in 25 (96.2%) with long-term recurrence in 25%.

CONCLUSIONS

Coherent mapping with conduction velocity vectors derived from adjacent mapping sites significantly improved the identification of CI sites in scar-related ATs with isthmus-dependent re-entry better than conventional mapping. It may be used in conjunction with conventional mapping strategies to facilitate recognition of slow conduction areas and critical sites that are important targets of ablation.

Ventricular divergence correlates with epicardial wavebreaks and predicts ventricular arrhythmia in isolated rabbit hearts during therapeutic hypothermia

INTRODUCTION

High beat-to-beat morphological variation (divergence) on the ventricular electrogram during programmed ventricular stimulation (PVS) is associated with increased risk of ventricular fibrillation (VF), with unclear mechanisms. We hypothesized that ventricular divergence is associated with epicardial wavebreaks during PVS, and that it predicts VF occurrence.

METHOD AND RESULTS

Langendorff-perfused rabbit hearts (n = 10) underwent 30-min therapeutic hypothermia (TH, 30°C), followed by a 20-min treatment with rotigaptide (300 nM), a gap junction modifier. VF inducibility was tested using burst ventricular pacing at the shortest pacing cycle length achieving 1:1 ventricular capture. Pseudo-ECG (p-ECG) and epicardial activation maps were simultaneously recorded for divergence and wavebreaks analysis, respectively. A total of 112 optical and p-ECG recordings (62 at TH, 50 at TH treated with rotigaptide) were analyzed. Adding rotigaptide reduced ventricular divergence, from 0.13±0.10 at TH to 0.09±0.07 (p = 0.018). Similarly, rotigaptide reduced the number of epicardial wavebreaks, from 0.59±0.73 at TH to 0.30±0.49 (p = 0.036). VF inducibility decreased, from 48±31% at TH to 22±32% after rotigaptide infusion (p = 0.032). Linear regression models showed that ventricular divergence correlated with epicardial wavebreaks during TH (p<0.001).

CONCLUSION

Ventricular divergence correlated with, and might be predictive of epicardial wavebreaks during PVS at TH. Rotigaptide decreased both the ventricular divergence and epicardial wavebreaks, and reduced the probability of pacing-induced VF during TH.

The presence of ectopic atrial rhythm predicts adverse cardiovascular outcomes in a large hospital-based population

BACKGROUND

Whether ectopic atrial rhythm (EAR) is a high-risk cardiovascular phenotype (eg, the manifestation of a diseased sinoatrial node) or just a benign accelerated ectopic pacemaker remains unclear.

OBJECTIVE

We aimed to analyze the cardiovascular outcomes and underlying mechanisms in patients with EAR.

METHODS

From a 12-lead electrocardiogram hospital-based electrocardiogram database, a total of 2896 adults with EAR were propensity score matched at 1:5 with 14,480 patients with sinus rhythm (SR). Patients were retrospectively followed up for cardiovascular mortality (the primary outcome) and permanent pacemaker implantation (the secondary outcome). Heart rate variability was analyzed to compare autonomic function between patients with EAR and those with SR.

RESULTS

The prevalence of EAR was 1.13%, which increased with age. Compared with the matched patients, those with EAR had a higher risk of cardiovascular mortality (adjusted hazard ratio 1.93; 95% confidence interval 1.52-2.44; P < .0001) and permanent pacemaker implantation (adjusted hazard ratio 5.94; 95% confidence interval 3.89-9.09; P < .0001) according to the Cox proportional hazards regression model. The risk of cardiovascular mortality was similar across the subgroups on the basis of age, sex, hypertension, type 2 diabetes mellitus, congestive heart failure, myocardial infarction, stroke, and chronic kidney diseases. In patients with EAR, the low frequency/high frequency and standard deviation of the mean normal-to-normal intervals/root mean square of successive RR interval differences ratios for heart rate variability were both lower than those in patients with SR. This implied autonomic imbalance in patients with EAR.

CONCLUSION

Patients with EAR have a higher risk of cardiovascular mortality and permanent pacemaker implantation, which was associated with autonomic imbalance.

Outcome of rescue ablation in patients with refractory ventricular electrical storm requiring mechanical circulation support

BACKGROUND

The management of refractory electrical storm (ES) requiring mechanical circulation support (MCS) remains a clinical challenge in structural heart disease (SHD).

OBJECTIVE

The study sought to explore the 30-day and 1-year outcome of rescue ablation for refractory ES requiring MCS in SHD.

METHODS

A total of 81 patients (mean age: 55.3 ± 18.9, 73 men [90.1%]) undergoing ablation were investigated, including 26 patients with ES requiring MCS (group 1) and 55 patients without (group 2). The 30-day and 1-year outcome, including mortality and recurrent ventricular tachyarrhythmias (VAs) receiving appropriate implantable cardioverter defibrillators therapies, were assessed.

RESULTS

The patients in group 1 were characterized by older age, more ischemic cardiomyopathies, worse left ventricular ejection fraction, and more comorbidities. Thirty days after ablation, overall events were seen in 15 patients (mortality in 10 and recurrent VA in 7), including pumping failure-related mortality in 6 (60%). During a 30-day follow-up, higher mortality was noted in group 1. After a 1-year follow-up, in spite of the higher mortality in group 1 (P < .001), the overall events and VA recurrences were similar between these two groups (P = .154 and P = .466, respectively). There was a significant reduction of VA burden in both groups and two patients had recurrent ES.

CONCLUSION

Higher 30-day mortality was observed in patients undergoing rescue ablation for refractory ES requiring MCS, and pumping failure was the major cause of periprocedural death. Rescue ablation successfully prevented VA recurrences and resulted in a comparable 1-year prognosis between ES with and without MCS.

Application of noninvasive signal-averaged electrocardiogram analysis in predicting the requirement of epicardial ablation in patients with arrhythmogenic right ventricular cardiomyopathy

BACKGROUND

Signal-averaged electrocardiogram (SAECG) provides not only diagnostic information but also the prognostic implication of ablation in arrhythmogenic right ventricular cardiomyopathy (ARVC).

OBJECTIVE

This study aimed to validate the role of SAECG in identifying arrhythmogenic substrates requiring an epicardial approach in ARVC.

METHODS

Ninety-one patients with a definite diagnosis of ARVC who underwent successful ablation for drug-refractory ventricular arrhythmia were enrolled and classified into 2 groups: group 1 who underwent successful ablation at the endocardium only and group 2 who underwent successful ablation requiring an additional epicardial approach. The baseline characteristics of patients and SAECG parameters were obtained for analysis.

RESULTS

Male predominance, worse right ventricular (RV) function, higher incidence of syncope, and depolarization abnormality were observed in group 2. Moreover, the number of abnormal SAECG criteria was higher in group 2 than in group 1. After a multivariate analysis, the independent predictors of the requirement of epicardial ablation included the number of abnormal SAECG criteria (odds ratio 2.8, 95% confidence interval 1.4-5.4; P = .003) and presence of syncope (odds ratio 11.7; 95% confidence interval 2.7-50.4; P = .001). In addition, ≥2 abnormal SAECG criteria were associated with larger RV endocardial unipolar low-voltage zone (P < .001), larger RV endocardial/epicardial bipolar low-voltage zone/scar (P < .05), and longer RV endocardial/epicardial total activation time (P < .001 and P = .004, respectively).

CONCLUSION

The number of abnormal SAECG criteria was correlated with the extent of diseased epicardial substrates and could be a potential surrogate marker for predicting the requirement of epicardial ablation in patients with ARVC.

Clinical efficacy of open-irrigated electrode cooled with half-normal saline for initially failed radiofrequency ablation of idiopathic outflow tract ventricular arrhythmias

BACKGROUND

Acute failure of radiofrequency ablation (RFA) of ventricular arrhythmias (VAs) occur in 10%-20% of patients and is partly attributed to inadequate lesion depth acquired with standard ablation protocols. Half-normal saline (HNS)-irrigation is a promising strategy to improve the success rate of VA ablation.

OBJECTIVE

This study investigated the efficacy of HNS-irrigated ablation after a failed standard plain normal saline solution (PNSS)-irrigated ablation on idiopathic outflow tract ventricular arrhythmia (OT-VA).

METHOD

This is a prospective observational study of consecutive patients undergoing RFA of idiopathic OT-VA comparing the efficacy of additional HNS-irrigated ablation for failed standard PNSS-irrigated ablation. Acute failure was defined as persistence of spontaneous VA or persistent inducibility of the clinical VA.

RESULTS

Out of 160 OT-VA cases (51 ± 15-year-old, 62 males), 31 underwent HNS irrigation after a failed standard PNSS-irrigated ablation. The HNS group had a significantly longer procedure time (60.06 ± 43.83 vs 37.51 ± 33.40 minutes; P = .013) and higher radiation exposure (31.45 ± 20.24 vs 17.22 ± 15.25 minutes; P = .001) than the PNSS group but provided an additional acute success in 21 of 31 (67.7%) patients. Over a follow-up duration of 7.8 ± 4.6 months, 24 recurrences were identified, including 8 (25.8%) in the HNS and 16 (12.4%) in the PNSS group, with lower freedom from recurrence in the HNS group (log rank P = .009). No major complication was observed.

CONCLUSION

HNS-irrigated ablation after failed standard PNSS-irrigated ablation is safe and additionally improves acute ablation success by 67.7% for idiopathic OT-VA but with a higher rate of recurrence on follow-up. Whether the application of HNS as initial irrigant could result in better outcome requires further investigation.

Low-Dose Rivaroxaban and Risks of Adverse Events in Patients With Atrial Fibrillation

Background and Purpose- In the daily practice, low-dose nonvitamin K antagonist oral anticoagulants are commonly used among Asian patients with atrial fibrillation (AF). The aim of the present study was to compare the risks of ischemic stroke, intracranial hemorrhage, and net clinical benefit of Asian patients with AF treated with off-label low-dose and on-label dosing rivaroxaban. Methods- A total of 2214 patients with AF aged ≥20 years treated with rivaroxaban at a tertiary medical center in Taiwan were studied. Patients were categorized into 2 groups: (1) on-label dose (n=1630): ROCKET-AF or J-ROCKET dosage criteria; and (2) off-label low-dose (10 mg/d for patients with an estimated glomerulus filtration rate >50 mL/min, n=584). The risks of ischemic stroke and intracranial hemorrhage were compared between 2 groups. Results- Compared with the on-label dose group, off-label low-dose rivaroxaban was associated with an increased risk of ischemic stroke with an adjusted hazard ratio of 2.75; 95% CI =1.62-4.69; P<0.001). The risk intracranial hemorrhage did not differ significantly between the on-label and off-label low-dosing groups (adjusted hazard ratio =0.62; 95% CI =0.32-1.20; P=0.213). Compared with off-label low-dose group, on-label dosing rivaroxaban was associated with a positive net clinical benefit in different weighted models. The results were consistent among the propensity-matched cohort. Conclusions- Off-label low-dosing rivaroxaban should be avoided for Asian patients with AF giving the higher risk of ischemic stroke without risk reduction in intracranial hemorrhage compared with on-label dosing.

Electrophysiological and clinical characteristics of catheter ablation for isolated left side atrial tachycardia over a 10-year period

AIMS

Most left atrial tachycardia (LAT) is associated with atrial fibrillation (AF). The clinical and electrophysiological characteristics and outcomes of LAT without AF have not been investigated. This study sought to determine the long-term ablation outcomes and predictors of recurrence of isolated LAT.

METHODS

This is a single-center study of consecutive patients with isolated LAT. Atrial arrhythmia recurrence was determined from follow-up records of patients who underwent LAT ablation from 2008 to 2017. Clinical and electrophysiologic characteristics associated with atrial arrhythmia recurrence were identified.

RESULTS

A total of 50 patients (53 ± 19 years, 46% male) with 59 LAT (1.16 ± 0.47 per patient) were enrolled. Over a mean follow-up of 37 ± 33 months, atrial arrhythmia recurrence occurred in 22 (44%) patients, 11 with atrial tachycardia (AT) only, five with AF only, and six with concurrent AT and AF. The incidence of pulmonary vein (PV) origins increased significantly in the repeat procedure (P = 0.036). Multivariate analysis identified left ventricular ejection fraction (LVEF) as the only predictor of any atrial arrhythmia recurrence and LAT recurrence, while smoking and identified macroreentrant LAT in the index procedure predicted AF recurrence.

CONCLUSION

This study demonstrated a higher rate of atrial arrhythmia recurrence, including AF, among patients with initially isolated LAT. A lower LVEF predicted any atrial arrhythmia and LAT recurrence, whereas smoking and index macroreentrant AT mechanism predicted long-term AF. PV ATs were frequently observed in recurrent patients irrespective of index procedure origin.

Circulating microRNAs in arrhythmogenic right ventricular cardiomyopathy with ventricular arrhythmia

Aims

MicroRNAs (miRNAs) have been implicated in cardiac diseases. This study aimed to characterize the circulating miRNAs in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) and correlate the miRNAs with the clinical outcomes of ARVC.

Methods and results

This study included 62 patients with ventricular arrhythmia (VA): 28 patients (45%) had definite ARVC, 11 (18%) had borderline or possible ARVC, and 23 (37%) had idiopathic ventricular tachycardia (VT). In addition, 33 age- and sex-matched healthy subjects were enrolled as normal control subjects. The expression of selected miRNAs was analysed in all study subjects. The clinical outcomes of patients with definite ARVC after catheter ablation were further investigated. On the basis of the miRNA polymerase chain reaction array, we selected 11 miRNAs for analysis of their expression in the plasma of all subjects. Definite ARVC patients had significantly higher expression of circulating miR-144-3p, 145-5p, 185-5p, and 494 than the three other groups. Out of 25 definite ARVC patients who underwent radiofrequency catheter ablation, recurrent VA occurred in 8 patients (32%) during the follow-up period (45 ± 20 months). Definite ARVC patients with recurrent VA had a higher level of circulating miR-494 than did those without recurrence. Receiver operating characteristic analysis showed miR-494 to be a predictive factor of recurrent VA (area under the curve: 0.832).

Conclusion

Plasma levels of miR-144-3p, 145-5p, 185-5p, and 494 were significantly elevated in definite ARVC patients with VA. An increased plasma level of miR-494 was associated with the recurrence of VA after ablation in definite ARVC patients.

Ten-year ablation outcomes of patients with paroxysmal atrial fibrillation undergoing pulmonary vein isolation

BACKGROUND

Pulmonary vein isolation (PVI) is commonly performed in patients with drug-refractory symptomatic paroxysmal atrial fibrillation (PAF). However, the very long-term follow-up result is limited.

OBJECTIVE

We aimed to investigate 10-year ablation outcomes in patients with PAF and long-term follow-up results after PVI.

METHODS

This study retrospectively enrolled 176 (131 men, mean age 51.2 ± 12.1 years) patients with drug-refractory symptomatic PAF who underwent electroanatomic-guided PVI. Ten-year follow-up was completed using medical records or telephonic interviews. Procedural characteristics at index procedures and long-term clinical outcomes were investigated.

RESULTS

After a mean follow-up period of 130.0 ± 10.8 months, sinus rhythm was achieved in 102 (58%) patients after a single procedure (including 14 (8%) patients on antiarrhythmic medications) and in 88% patients after multiple procedures (including 17 (10%) patients on antiarrhythmic medications). Left atrial diameter (odds ratio 1.067; 95% confidence interval 1.009-1.127; P = .023) was the predictor of recurrent atrial tachyarrhythmia after a single ablation procedure. The single-procedure recurrence-free rates were similar between circumferential PVI and segmental PVI (59% and 50%; log-rank, P = .251). The recurrence patterns of both groups regarding the role of non-pulmonary vein and pulmonary vein triggers were similar.

CONCLUSION

The single-procedure long-term efficacy was modest, with freedom from atrial fibrillation at 10 years being 58%. Those who had enlarged left atrial diameters have more atrial tachyarrhythmia recurrences. Ten-year single-procedure outcomes of the effects of circumferential PVI and segmental PVI in patients with PAF were similar.

Uninterrupted non-vitamin K antagonist oral anticoagulants during implantation of cardiac implantable electronic devices in patients with atrial fibrillation

BACKGROUND

For patients with atrial fibrillation (AF) receiving cardiac implantable electronic device (CIED) implantations, current consensus recommends uninterrupted non-vitamin K antagonist oral anticoagulant (NOAC) considering low incidence of bleeding or thrombo-embolic events. It remains unknown whether uninterrupted strategy outweighs discontinuation method for patients receiving NOAC.

METHODS

From January 1, 2013 to June 1, 2017, we enrolled 100 patients (mean age 78.3 ± 10.2 years, 58% male) with AF taking NOAC for stroke prevention eligible for CIED implantation in a tertiary medical center, Taipei, Taiwan. NOAC was continued without skipping any doses during the surgery. The baseline characteristics, underlying diseases, CHA2DS2-VASc score, and clinical course of every patient were reviewed and analyzed.

RESULTS

Among these patients, 28 were on dabigatran, 61 on rivaroxaban, 10 on apixaban, and one on edoxaban, respectively. There were no adverse events except one case of pericardial effusion and another one with large pocket hematoma. One patient receiving implantable cardioverter defibrillator implantation had late onset of pericardial effusion with impending tamponade necessitating pericardiocentesis. Another patient had large pocket hematoma, which spontaneously resolved within 1 month without further intervention. No periprocedural mortality and stroke occurred.

CONCLUSION

Uninterrupted NOAC during CIED implantations may be an acceptable option especially in patients with high risk for thromboembolism. However, special caution should be paid during defibrillator implantation considering relatively higher risk of bleeding, perhaps due to the larger size of the defibrillator lead.

Incident Co-Morbidities in Patients with Atrial Fibrillation Initially with a CHA2DS2-VASc Score of 0 (Males) or 1 (Females): Implications for Reassessment of Stroke Risk in Initially ‘Low-Risk’ Patients

Background Oral anticoagulants (OACs) are not recommended for ‘low-risk’ patients with atrial fibrillation (AF). We investigated the incidences of new risk factors developing, and the temporal trends in the CHA2DS2-VASc score in initially ‘low-risk’ AF patients. Second, we propose a reasonable timing interval at which stroke risk should be reassessed for such AF patients.

Methods We studied 14,606 AF patients who did not receive anti-platelet agents or OACs with a baseline CHA2DS2-VASc score of 0 (males) or 1 (females). The CHA2DS2-VASc scores of patients were followed up and updated until the occurrence of ischaemic stroke or mortality or 31 December 2011. The associations between the prescription of warfarin and risk of adverse events once patients' scores changed were analysed. Decile values of durations to incident co-morbidities and from the acquirement of new co-morbidities to ischaemic stroke were studied.

Results During a mean follow-up of 4 years, 7,079 (48.5%) patients acquired at least one new stroke risk factor component(s) with annual risks of 6.35% for hypertension, 3.68% for age ≥ 65 years, 2.77% for heart failure, 1.99% for diabetes mellitus and 0.33% for vascular diseases. The incidence for CHA2DS2-VASc score increments was 12.1%/year. Initiation of warfarin was associated with a lower risk of adverse events (adjusted hazard ratio, 0.530; 95% confidence interval, 0.371–0.755). Among 6,188 patients who acquired new risk factors, 80% would acquire these co-morbidities after 4.2 months of AF diagnosis. The duration from the acquirement of incident co-morbidities to the occurrence of ischaemic stroke was longer than 4.4 months for 90% of the patients.

Conclusion The CHA2DS2-VASc score increases in approximately 12% of initially ‘low-risk’ AF patients each year, and the initiation of warfarin once the score changed was associated with a better prognosis. Three to four months may be a reasonable timing interval at which stroke risk should be reassessed so that OACs could be prescribed in a timely manner for stroke prevention.

A link between bilirubin levels and atrial fibrillation recurrence after catheter ablation

BACKGROUND

Bilirubin is associated with different cardiovascular diseases. The relationship between bilirubin and atrial fibrillation (AF) remains unclear. The aim of this study is to determine the association between bilirubin and AF recurrence after catheter ablation.

METHODS

A total of 212 patients who received AF ablation were retrospectively studied. The total bilirubin level, clinical characteristics, and echocardiographic findings were analyzed to predict the outcome of AF ablations.

RESULTS

During a mean follow-up period of 12.2 ± 5.8 months, 61 (28.8%) patients had AF recurrence after catheter ablation. The patients with AF recurrence had a larger left atrial (LA) diameter (39.8 ± 6.3 versus 36.7 ± 5.8 mm; p = 0.001) and higher total bilirubin levels (0.82 ± 0.37 versus 0.63 ± 0.29 mg/dL; p < 0.001) than those without recurrence. The patients with recurrence had higher direct and indirect bilirubin levels than patients without recurrence. The total bilirubin level remained an independent predictor of AF recurrence after multivariate analysis (odds ratio, 4.95; 95% CI, 1.65-14.83; p = 0.004). We identified a cut point of the total bilirubin level for predicting AF recurrence by receiver operator characteristic curve (cut point, 0.7 mg/dL; area under the curve, 0.65; p < 0.001). The total bilirubin levels were positively correlated with the neutrophil counts. However, there were no associations among the total bilirubin level, left atrial (LA) diameter, and voltage.

CONCLUSION

Higher serum bilirubin levels were associated with AF recurrence in paroxysmal AF patients following catheter ablation.

Characteristics of recurrent ventricular tachyarrhythmia after catheter ablation in patients with arrhythmogenic right ventricular cardiomyopathy

BACKGROUND

The reason for recurrence of ventricular arrhythmia (VA) after catheter ablation in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) is not clear.

METHODS

In this study, 91 ARVC patients (age, 47 ± 13 years; 47 men) who underwent catheter ablation for drug-refractory ventricular arrhythmia (VA) were enrolled. The patients were categorized into single or multiple procedures (n = 28). The baseline characteristics and electrophysiological features of the patients were examined to elucidate the reason of the VA recurrences.

RESULTS

A total of 186 VAs were induced during the index procedure and 176 (94.6%) were eliminated. Successful, partially successful, and failed ablations were achieved in 89.0%, 8.8%, and 2.2% of the patients, respectively. During a mean follow-up period of 32 ± 26 months, 35 patients had VA recurrences. Forty-two repeat procedures were performed for 81 induced VAs in 28 patients. Of the 42 repeat procedures, successful, partially successful, and failed ablations were achieved in 37, 4, and 1 of the procedures, respectively. Most of the recurrent VAs (70 [72.9%]) originated from the newly-developed circuits owing to the scar progression. The patients with repeat procedure had worsening right ventricular remodeling. The multivariate analysis revealed that history as endurance athlete significantly predicted the need of a repeat procedure in spite of the initially successful endocardial/epicardial ablation and negative inducibility (hazard ratio: 3.014, 95% confidence interval: 1.493-6.084, P = 0.002).

CONCLUSIONS

In spite of the initial complete VA elimination, history as an athlete was associated with scar progression, RV remodeling, and VA recurrences from the newly developed arrhythmogenic substrates/circuit in ARVC.

Dynamic unipolar voltage criteria of right ventricular septum for identifying left ventricular septal scar

PURPOSE

The right ventricular (RV) septal unipolar voltage (UV) for predicting left ventricular (LV) septal scar wall thickness (WT) remains to be elucidated.

METHODS

From 2013 to 2015, data obtained from RV and LV electroanatomic maps of 28 patients (mean age, 53 ± 16 years; 19 men [67.9%]) with/without identified LV septal scars were reviewed. Patients with an RV septal scar were excluded (n = 90). Direct measurement of septal WT was conducted (mean distance, 10.4 ± 3.3 mm). Patients in group 1 had a normal LV substrate, while those in group 2 had an LV septal scar. Fisher's linear discriminant formula was used to determine the dynamic UV criteria.

RESULTS

A total of 552 points were collected: 323 in 12 patients from group 1 and 229 in 16 patients from group 2. The UV of the RV septum is capable of identifying the opposite LV endocardial bipolar scar and is proportional to the WT of the interventricular septum. In the absence of an RV endocardial scar, the formula of "RV septal cut-off value = 0.736 × WT - 0.117 mV" has better sensitivity and specificity for predicting the LV septal scar (0.96 vs. 0.68 and 0.91 vs. 0.80, respectively) than the predefined fixed criteria of 8.3 mV with a net reclassification improvement of 25.7% (P < 0.001).

CONCLUSIONS

The combined measurement of UV and WT is more sensitive than the predefined fixed UV criteria for defining deep scars.