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Background and Objectives@#Inherited arrhythmia (IA) is a more common cause of sudden cardiac death in Asian population, but little is known about the genetic background of Asian IA probands. We aimed to investigate the clinical characteristics and analyze the genetic underpinnings of IA in a Korean cohort. @*Methods@#This study was conducted in a multicenter cohort of the Korean IA Registry from 2014 to 2017. Genetic testing was performed using a next-generation sequencing panel including 174 causative genes of cardiovascular disease. @*Results@#Among the 265 IA probands, idiopathic ventricular fibrillation (IVF) and Brugada Syndrome (BrS) was the most prevalent diseases (96 and 95 cases respectively), followed by long QT syndrome (LQTS, n=54). Two-hundred-sixteen probands underwent genetic testing, and 69 probands (31.9%) were detected with genetic variant, with yield of pathogenic or likely pathogenic variant as 6.4%. Left ventricular ejection fraction was significantly lower in genotype positive probands (54.7±11.3 vs. 59.3±9.2%, p=0.005). IVF probands showed highest yield of positive genotype (54.0%), followed by LQTS (23.8%), and BrS (19.5%). @*Conclusions@#There were significant differences in clinical characteristics and genetic yields among BrS, LQTS, and IVF. Genetic testing did not provide better yield for BrS and LQTS. On the other hand, in IVF, genetic testing using multiple gene panel might enable the molecular diagnosis of concealed genotype, which may alter future clinical diagnosis and management strategies.
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Background and Objectives@#Atrial fibrillation (AF) is associated with decreased cardiac resynchronization therapy (CRT) benefits compared to sinus rhythm (SR). Effective biventricular (BiV) pacing is a determinant of CRT success, but AF can interfere with adequate BiV pacing and affect clinical outcomes. We investigated the effect of device-detected AF on clinical outcomes and optimal BiV pacing in patients with heart failure (HF) treated with CRT. @*Methods@#We retrospectively analyzed 174 patients who underwent CRT implantation between 2012 and 2019 at a tertiary center. The optimal BiV pacing percentage was defined as ≥98%. Device-detected AF was defined as an atrial high-rate episode ≥180 beats per minute lasting more than 6 minutes during the follow-up period. We stratified the patients without preexisting AF at pre-implantation into device-detected AF and no-AF groups. @*Results@#A total of 120 patients did not show preexisting AF at pre-implantation, and 54 had AF. Among these 120 patients, 19 (15.8%) showed device-detected AF during a median follow-up of 25.1 months. The proportion of optimal BiV pacing was significantly lower in the device-detected AF group than in the no-AF group (42.1% vs. 75.2%, p=0.009). The devicedetected AF group had a higher incidence of HF hospitalization, cardiovascular death, and all-cause death than the no-AF group. The device-detected AF and previous AF groups showed no significant differences regarding the percentage of BiV pacing and clinical outcomes. @*Conclusions@#For HF patients implanted with CRT, device-detected AF was associated with lower optimal BiV pacing and worse clinical outcomes than no-AF.
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Background@#Traditional right ventricular apical pacing can cause electrical–mechanical dyssynchrony. Therefore, physiological conduction system pacing was considered and became the reason for developing His bundle pacing (HBP). Recently, left bundle branch area pacing (LBBAP) has been implemented, which overcomes the shortcomings of HBP. Most initial large LBBAP studies reported that LBBAP was achieved through a lumenless pacing lead (LLL) with a fixed helix design; however, it is unavailable in Korea. LBBAP delivery sheaths using a conventional standard styletdriven pacing lead (SDL) with an extendable helix design are currently available in Korea. In this review, we describe the methods and procedural skills required to perform the LBBAP using conventional SDL.Main body LBBAP has emerged as a new physiological CSP modality and has shown a stable and lower capture threshold and achieved a similarly paced QRS duration compared to HBP. It has also demonstrated stable early outcomes for feasibility and safety with a high success rate. Furthermore, the application of LBBAP has recently been extended to a resynchronization strategy. The LBBAP with SDL requires different handling and lead preparation owing to differences in lead and helix designs. Reported procedure-related acute complications of LBBAP include septal per‑ foration during the procedure, pneumothorax, pocket infection, pocket hematoma, and lead dislodgements occur‑ ring during follow-up. @*Conclusion@#LBBAP with conventional SDL has similar implant success rates, procedural safety, and pacing character‑ istics as LBBAP with LLL. However, LBBAP with SDL requires different handling and lead preparation from that of LLL owing to the differences in the lead and helix designs.
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Background and Objectives@#Atrial tachycardias (ATs) from noncoronary aortic cusp (NCC) uncovered after radiofrequency ablation for atrial fibrillation (AF) are rarely reported. This study was conducted to investigate the prevalence and clinical characteristics of NCC ATs detected during AF ablation and compare their characteristics with de novo NCC ATs without AF. @*Methods@#Consecutive patients who underwent radiofrequency catheter ablation for AF were reviewed from the multicenter AF ablation registry of 11 tertiary hospitals. The clinical and electrophysiological characteristics of NCC AT newly detected during AF ablation were compared with its comparators (de novo NCC AT ablation cases without AF). @*Results@#Among 10,178 AF cases, including 1,301 redo ablation cases, 8 (0.08%) NCC AT cases were discovered after pulmonary vein isolation (PVI; 0.07% in first ablation and 0.15% in redo ablation cases). All ATs were reproducibly inducible spontaneously or with programmed atrial stimulation without isoproterenol infusion. The P-wave morphological features of tachycardia were variable depending on the case, and most cases exhibited 1:1 atrioventricular conduction. AF recurrence rate after PVI and NCC AT successful ablation was 12.5% (1 of 8). Tachycardia cycle length was shorter than that of 17 de novo ATs from NCC (303 versus 378, p=0.012). No AV block occurred during and after successful AT ablation. @*Conclusions@#Uncommon NCC ATs (0.08% in AF ablation cases) uncovered after PVI, showing different characteristics compared to de-novo NCC ATs, should be suspected irrespective of P-wave morphologies when AT shows broad propagation from the anterior interatrial septum.
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Background@#Conventional modality requires several days observation by Holter monitor to differentiate atrial fibril‑ lation (AF) between Paroxysmal atrial fibrillation (PAF) and Non-paroxysmal atrial fibrillation (Non-PAF). Rapid and practical differentiating approach is needed. @*Objective@#To develop a machine learning model that observes 10-s of standard 12-lead electrocardiograph (ECG) for real-time classification of AF between PAF versus Non-PAF. @*Methods@#In this multicenter, retrospective cohort study, the model training and cross-validation was performed on a dataset consisting of 741 patients enrolled from Severance Hospital, South Korea. For cross-institutional validation, the trained model was applied to an independent data set of 600 patients enrolled from Ewha University Hospital, South Korea. Lasso regression was applied to develop the model. @*Results@#In the primary analysis, the Area Under the Receiver Operating Characteristic Curve (AUC) on the test set for the model that predicted AF subtype only using ECG was 0.72 (95% CI 0.65–0.80). In the secondary analysis, AUC only using baseline characteristics was 0.53 (95% CI 0.45–0.61), while the model that employed both baseline characteris‑ tics and ECG parameters was 0.72 (95% CI 0.65–0.80). Moreover, the model that incorporated baseline characteristics, ECG, and Echocardiographic parameters achieved an AUC of 0.76 (95% CI 0.678–0.855) on the test set. @*Conclusions@#Our machine learning model using ECG has potential for automatic differentiation of AF between PAF versus Non-PAF achieving high accuracy. The inclusion of Echocardiographic parameters further increases model per‑ formance. Further studies are needed to clarify the next steps towards clinical translation of the proposed algorithm.
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Background@#Cardiac resynchronization therapy (CRT) is an effective treatment option for patients with heart failure (HF) and left ventricular (LV) dyssynchrony. However, the problem of some patients not responding to CRT remains unresolved. This study aimed to propose a novel in silico method for CRT simulation. @*Methods@#Three-dimensional heart geometry was constructed from computed tomography images. The finite ele‑ ment method was used to elucidate the electric wave propagation in the heart. The electric excitation and mechani‑ cal contraction were coupled with vascular hemodynamics by the lumped parameter model. The model parameters for three-dimensional (3D) heart and vascular mechanics were estimated by matching computed variables with measured physiological parameters. CRT effects were simulated in a patient with HF and left bundle branch block (LBBB). LV end-diastolic (LVEDV) and end-systolic volumes (LVESV), LV ejection fraction (LVEF), and CRT responsiveness measured from the in silico simulation model were compared with those from clinical observation. A CRT responder was defined as absolute increase in LVEF ≥ 5% or relative increase in LVEF ≥ 15%. @*Results@#A 68-year-old female with nonischemic HF and LBBB was retrospectively included. The in silico CRT simu‑ lation modeling revealed that changes in LVEDV, LVESV, and LVEF by CRT were from 174 to 173 mL, 116 to 104 mL, and 33 to 40%, respectively. Absolute and relative ΔLVEF were 7% and 18%, respectively, signifying a CRT responder.In clinical observation, echocardiography showed that changes in LVEDV, LVESV, and LVEF by CRT were from 162 to 119 mL, 114 to 69 mL, and 29 to 42%, respectively. Absolute and relative ΔLVESV were 13% and 31%, respectively, also signifying a CRT responder. CRT responsiveness from the in silico CRT simulation model was concordant with that in the clinical observation. @*Conclusion@#This in silico CRT simulation method is a feasible technique to screen for CRT non-responders in patients with HF and LBBB.
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Background@#This study aims to investigate the current status of AF (atrial fibrillation) catheter ablation in Korea. @*Methods@#The patients who underwent AF catheter ablation from September 2017 to December 2019 were pro‑ spectively enrolled from 37 arrhythmia centers. Demographic data, procedural characteristics, the extent of catheter ablation, acute success of the ablation lesion set, rate and independent risk factor for recurrence of AF were analyzed. @*Results@#A total of 2402 AF patients [paroxysmal AF (PAF) 45.7%, persistent AF (PeAF) 43.1% and redo AF 11.2%] were included. Pulmonary vein isolation (PVI) was performed in 2378 patients (99%) and acute success rate was 97.9%.Additional non-PV ablation (NPVA) were performed in 1648 patients (68.6%). Post-procedural complication rate was 2.2%. One-year AF-free survival rate was 78.6% and the PeAF patients showed poorer survival rate than the ones with other types (PeAF 72.4%, PAF 84.2%, redo AF 80.0%). Additional NPVA did not influence the recurrence of AF in the PAF patients (PVI 17.0% vs. NPVA 14.6%, P value 0.302). However, it showed lower AF recurrence rate in the PeAF patients (PVI 34.9% vs. NPVA 24.4%, P value 0.001). Valvular heart disease, left atrial diameter, PeAF, PVI alone, need of NPVA for terminating AF, and failed ablation were independent predictors of AF recurrence. @*Conclusions@#Additional NPVA was associated better rhythm outcome in the patients with PeAF, not in the ones with PAF. The independent risk factors for AF recurrence in Korean population were similar to previous studies. Further research is needed to discover optimal AF ablation strategy.
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With the aging society, the prevalence of atrial fibrillation (AF) continues to increase. Nevertheless, there are still limitations in antiarrhythmic drugs (AAD) or catheter interventions for AF. If it is possible to predict the outcome of AF management according to various AADs or ablation lesion sets through computational modeling, it will be of great clinical help. AF computational modeling has been utilized for in-silico arrhythmia research and enabled high-density entire chamber mapping, reproducible condition control, virtual intervention, not possible clinically or experimentally, in-depth mechanistic research. With the recent development of computer science and technology, more sophisti‑ cated and faster computational modeling has become available for clinical application. In particular, it can be applied to determine the extra-PV target of persistent AF catheter ablation or to select the AAD with the best effect. AF com‑ putational modeling combined with artificial intelligence is expected to contribute to precision medicine for more diverse uses in the future. Therefore, in this review, we will deal with the history, development, and various applica‑ tions of computation modeling.
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Background and Objectives@#Prior studies have shown that stroke patients treated with percutaneous left atrial appendage occlusion (LAAO) for non-valvular atrial fibrillation (NVAF) experience better outcomes than similar patients treated with warfarin. We investigated the impact of percutaneous left atrial appendage closure on post-stroke neurological outcomes in NVAF patients, compared with non-vitamin K antagonist oral anticoagulant (NOAC) therapy. @*Methods@#Medical records for 1,427 patients in multiple registries and for 1,792 consecutive patients at 6 Korean hospitals were reviewed with respect to LAAO or NOAC treatment.Stroke severity in patients who experienced ischemic stroke or transient ischemic attack after either treatment was assessed with modified Rankin Scale (mRS) scoring at hospital discharge and at 3 and 12 months post-stroke. @*Results@#mRS scores were significantly lower in LAAO patients at 3 (p<0.01) and 12 months (p<0.01) post-stroke, despite no significant differences in scores before the ischemic cerebrovascular event (p=0.22). The occurrences of disabling ischemic stroke in the LAAO and NOAC groups were 36.7% and 44.2% at discharge (p=0.47), 23.3% and 44.2% at 3 months post-stroke (p=0.04), and 13.3% and 43.0% at 12 months post-stroke (p=0.01), respectively.Recovery rates for disabling ischemic stroke at discharge to 12 months post-stroke were significantly higher for LAAO patients (50.0%) than for NOAC patients (5.6%) (p<0.01). @*Conclusions@#Percutaneous LAAO was associated with more favorable neurological outcomes after ischemic cerebrovascular event than NOAC treatment.
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Background@#Ablation of idiopathic ventricular arrhythmias (VAs) in the cardiac crux region is one of the challenging procedures due to the complex anatomical structure where the four chambers of the heart are offset. Although this region is complex, the contiguous cardiac structures allow for the ablation of arrhythmias from adjacent sites.Case presentation: We present different anatomical approaches in radiofrequency ablation and the ECG character‑ istics from a case series of VAs originated from the basal inferior ventricular septum, the corresponding endocardial aspect of the basal cardiac crux region. @*Conclusions@#Ablation of VAs originated from the basal cardiac crux region requires detailed mapping in the proxi‑ mal coronary venous system and the adjacent structures including the RV, RA, and LV. In addition to the characteristic ECG of basal crux VAs, our three cases present an abrupt precordial transition in V2 with R wave amplitude greater than in V1 and V3.
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Background@#We aimed to investigate the comparative risk of fracture among patients with atrial fibrillation (AF) treated with warfarin or non-vitamin K antagonist oral anticoagulants (NOACs). @*Methods@#Using the Korean National Health Insurance Service database, patients with AF who received a prescrip‑ tion for apixaban, dabigatran, rivaroxaban, or warfarin between 2013 and 2016 were included. Risk of major fractures (osteoporotic hip, vertebral, or pelvic fractures) were compared using inverse probability of treatment weighting. @*Results@#There were 70,481 patients identified (41.3% women; mean [SD] age 70.5 [11.3] years); 16,992 apixaban, 22,514 dabigatran, 27,998 rivaroxaban, and 29,390 warfarin users. During a median follow-up of 390 days, 2412 major fractures occurred with weighted incidences per 100 patient-years of 2.56 for apixaban, 2.39 for dabigatran, 2.78 for rivaroxaban, and 3.43 for warfarin. NOAC use was associated with a lower risk for fracture than warfarin use: HR 0.70 (95% confidence interval [CI] 0.57–0.86) for apixaban, HR 0.69 (95% CI 0.60–0.78) for dabigatran, and HR 0.79 (95% CI 0.70–0.90) for rivaroxaban. In head-to-head comparisons between NOACs, there was no significant difference between apixaban and dabigatran. Rivaroxaban was associated with a higher risk for fracture than dabigatran (HR 1.15, 95% CI 1.02–1.31). @*Conclusion@#In patients with AF, NOAC use may result in a lower risk for osteoporotic fracture compared with warfa‑ rin use. Fracture risk does not seem to be altered by the choice of NOAC type, except for rivaroxaban. These associa‑ tions may help inform benefit–risk assessments when choosing between the different anticoagulant types.
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Background@#Atrioventricular (AV) node normally has decremental conduction property and a longer refractory period than His-Purkinje system (HPS). This results in AV conduction delay or block at the level of AV node in response to short-coupled atrial premature beats. Prolonged refractoriness in HPS can produce unusual physiological patterns of AV conduction such as conduction delay or infra-nodal block in the distal elements of HPS.Case presentation: We present a case in which atrial premature stimulation produces infra-nodal Wenckebach conduction block which initiates long-short cycle sequence within the bundle branches resulted in alternating bundle branch block and atypical pattern of Ashman phenomenon. @*Conclusions@#This case highlights the importance of recognizing the unusual physiological AV conduction patterns of HPS. The long-short cycle sequence in the bundle branches of distal HPS and linking phenomenon can result in alternating bundle branch block without the presence of HPS disease.
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Background and Objectives@#Prior studies have shown that stroke patients treated with percutaneous left atrial appendage occlusion (LAAO) for non-valvular atrial fibrillation (NVAF) experience better outcomes than similar patients treated with warfarin. We investigated the impact of percutaneous left atrial appendage closure on post-stroke neurological outcomes in NVAF patients, compared with non-vitamin K antagonist oral anticoagulant (NOAC) therapy. @*Methods@#Medical records for 1,427 patients in multiple registries and for 1,792 consecutive patients at 6 Korean hospitals were reviewed with respect to LAAO or NOAC treatment.Stroke severity in patients who experienced ischemic stroke or transient ischemic attack after either treatment was assessed with modified Rankin Scale (mRS) scoring at hospital discharge and at 3 and 12 months post-stroke. @*Results@#mRS scores were significantly lower in LAAO patients at 3 (p<0.01) and 12 months (p<0.01) post-stroke, despite no significant differences in scores before the ischemic cerebrovascular event (p=0.22). The occurrences of disabling ischemic stroke in the LAAO and NOAC groups were 36.7% and 44.2% at discharge (p=0.47), 23.3% and 44.2% at 3 months post-stroke (p=0.04), and 13.3% and 43.0% at 12 months post-stroke (p=0.01), respectively.Recovery rates for disabling ischemic stroke at discharge to 12 months post-stroke were significantly higher for LAAO patients (50.0%) than for NOAC patients (5.6%) (p<0.01). @*Conclusions@#Percutaneous LAAO was associated with more favorable neurological outcomes after ischemic cerebrovascular event than NOAC treatment.
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Background@#Ablation of idiopathic ventricular arrhythmias (VAs) in the cardiac crux region is one of the challenging procedures due to the complex anatomical structure where the four chambers of the heart are offset. Although this region is complex, the contiguous cardiac structures allow for the ablation of arrhythmias from adjacent sites.Case presentation: We present different anatomical approaches in radiofrequency ablation and the ECG character‑ istics from a case series of VAs originated from the basal inferior ventricular septum, the corresponding endocardial aspect of the basal cardiac crux region. @*Conclusions@#Ablation of VAs originated from the basal cardiac crux region requires detailed mapping in the proxi‑ mal coronary venous system and the adjacent structures including the RV, RA, and LV. In addition to the characteristic ECG of basal crux VAs, our three cases present an abrupt precordial transition in V2 with R wave amplitude greater than in V1 and V3.
ABSTRACT
Background@#We aimed to investigate the comparative risk of fracture among patients with atrial fibrillation (AF) treated with warfarin or non-vitamin K antagonist oral anticoagulants (NOACs). @*Methods@#Using the Korean National Health Insurance Service database, patients with AF who received a prescrip‑ tion for apixaban, dabigatran, rivaroxaban, or warfarin between 2013 and 2016 were included. Risk of major fractures (osteoporotic hip, vertebral, or pelvic fractures) were compared using inverse probability of treatment weighting. @*Results@#There were 70,481 patients identified (41.3% women; mean [SD] age 70.5 [11.3] years); 16,992 apixaban, 22,514 dabigatran, 27,998 rivaroxaban, and 29,390 warfarin users. During a median follow-up of 390 days, 2412 major fractures occurred with weighted incidences per 100 patient-years of 2.56 for apixaban, 2.39 for dabigatran, 2.78 for rivaroxaban, and 3.43 for warfarin. NOAC use was associated with a lower risk for fracture than warfarin use: HR 0.70 (95% confidence interval [CI] 0.57–0.86) for apixaban, HR 0.69 (95% CI 0.60–0.78) for dabigatran, and HR 0.79 (95% CI 0.70–0.90) for rivaroxaban. In head-to-head comparisons between NOACs, there was no significant difference between apixaban and dabigatran. Rivaroxaban was associated with a higher risk for fracture than dabigatran (HR 1.15, 95% CI 1.02–1.31). @*Conclusion@#In patients with AF, NOAC use may result in a lower risk for osteoporotic fracture compared with warfa‑ rin use. Fracture risk does not seem to be altered by the choice of NOAC type, except for rivaroxaban. These associa‑ tions may help inform benefit–risk assessments when choosing between the different anticoagulant types.
ABSTRACT
Background@#Atrioventricular (AV) node normally has decremental conduction property and a longer refractory period than His-Purkinje system (HPS). This results in AV conduction delay or block at the level of AV node in response to short-coupled atrial premature beats. Prolonged refractoriness in HPS can produce unusual physiological patterns of AV conduction such as conduction delay or infra-nodal block in the distal elements of HPS.Case presentation: We present a case in which atrial premature stimulation produces infra-nodal Wenckebach conduction block which initiates long-short cycle sequence within the bundle branches resulted in alternating bundle branch block and atypical pattern of Ashman phenomenon. @*Conclusions@#This case highlights the importance of recognizing the unusual physiological AV conduction patterns of HPS. The long-short cycle sequence in the bundle branches of distal HPS and linking phenomenon can result in alternating bundle branch block without the presence of HPS disease.
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Purpose@#Cardiovascular health (CVH) status is associated with several cardiovascular outcomes; however, correlations between changes in CVH status and risk of sudden cardiac death (SCD) are unknown. We aimed to evaluate associations between changes in CVH status and risk of SCD and all-cause death in older adults. @*Materials and Methods@#We used data from the Korea National Health Insurance Service-Senior cohort database (2005–2012). Six metrics from the American Heart Association (smoking, body mass index, physical activity, blood pressure, total cholesterol, and fasting blood glucose) were used to calculate CVH scores. Changes in CVH status between two health checkups were categorized as low to low, low to high, high to low, and high to high. @*Results@#We included 105200 patients whose CVH status for an initial and follow-up health checkup (2-year interval) was available. During a median of 5.2 years of follow-up after a second health checkup, 688 SCDs occurred. Compared to patients with a persistent low CVH status, those with a consistently high CVH status had a reduced risk of SCD [adjusted hazard ratio (HR), 0.69; 95% confidence interval (CI), 0.56–0.86] and all-cause death (adjusted HR, 0.74; 95% CI, 0.69–0.78). The risk of all-cause death followed similar trends. However, an inconsistent linear relationship was observed for changes in CVH status and the risk of SCD, but not of all-cause death. @*Conclusion@#Maintaining a high CVH status was associated with future risks of SCD and all-cause death among an older adult population.
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Background@#Although myocardial thickness is an important variable for therapeutic catheter ablation of cardiac arrhythmias, quantification of wall thickness has been overlooked. We developed a software (AMBER) that measures 3D-myocardial thickness using a cardiac computed tomogram (CT) image, verified its accuracy, and tested its clinical feasibility. @*Methods@#We generated 3D-thickness maps by calculating wall thickness (WT) from the CT images of 120 patients’ hearts and a 3D-phantom model (PhM). The initial vector field of the Laplace equation was oriented to calculate WT with the field lines derived from the 3D mesh. We demonstrate the robustness of the Laplace WT algorithm by comparing with the real thickness of 3D-PhM, echocardiographically measured left ventricular (LV) WT, and regional left atrial (LA) WT reported from previous studies. We conducted a pilot case of catheter ablation for atrial fibrillation (AF) utilizing real-time LAWT map-guided radiofrequency (RF) energy titration. @*Results@#AMBER 3D-WT had excellent correlations with the real thickness of the PhM (R = 0.968, p < 0.001) and echocardiographically measured LVWT in 10 patients (R = 0.656, p = 0.007). AMBER 3D-LAWT (n = 120) showed a relatively good match with 12 previously reported regional LAWT. We successfully conducted pilot AF ablation utilizing AMBER 3D-LAWT map-guided real-time RF energy titration. @*Conclusion@#We developed and verified an AMBER 3D-cardiac thickness map measured by cardiac CT images for LAWT and LVWT, and tested its feasibility for RF energy titration during clinical catheter ablation.
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Background and objectives@#Atrial fibrillation is a known risk factor for cryptogenic stroke and therefore requires early detection and prompt management. We investigated predictors of stroke recurrence in patients with cryptogenic stroke and concomitant non-sustained atrial tachycardia but not atrial fibrillation. @*Subjects and methods@#We investigated 390 patients (219 men, mean age 67 ± 12 years) diagnosed with stroke and non-sustained atrial tachycardia on 24-h Holter monitoring and recorded the total number of atrial premature contractions identified by the Holter monitor. Multiple atrial premature contractions were defined as atrial premature contractions > 34 beats/day. We analyzed the rates of 5-year freedom from stroke recurrence or atrial fibrillation and investigated independent predictors of stroke recurrence and undiagnosed atrial fibrillation. @*Results@#The mean follow-up period was 35 ± 21 months, and the overall stroke recurrence rate was 9.0%. Kaplan–Meier survival analysis revealed that the rate of freedom from stroke recurrence was significantly lower in patients with multiple atrial premature contractions. Also, the patients with multiple atrial premature contractions had higher cumulative incidence rate of new-onset AF (p = 0.019). Multivariate analysis showed that multiple atrial premature contractions (hazard ratio 2.49, 95% confidence interval 1.05–5.88, p = 0.038), cigarette smoking status (hazard ratio 2.66, 95% confidence interval 1.15–6.17, p = 0.022), and the left atrial volume index (hazard ratio 1.05, 95% confidence interval 1.01–1.09, p = 0.020) were significantly associated with stroke recurrence in patients with cryptogenic stroke. However, these factors were not statistically significant predictors of future onset of atrial fibrillation. @*Conclusions@#Multiple atrial premature contractions were significantly correlated with an increased left atrial volume index, which could predict future onset of atrial fibrillation and stroke recurrence. This study showed that multiple atrial premature contractions predict stroke recurrence in patients with cryptogenic stroke without atrial fibrillation.
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Background and objectives@#A prolonged QTc interval is associated with an increased risk of a stroke or atrial fibrillation (AF). However, its direct causal relationship with AF associated a stroke has not been proven yet. To examine whether QTc interval is causally linked with risk of stroke in AF patients, we used the Mendelian randomization analysis. @*Subjects and methods@#Among 2742 patients (73.6% male; 58.2 ± 11.0 years old; 69.5% with paroxysmal AF) who underwent AF catheter ablation, we analyzed 1766 patients who had preablation sinus rhythm electrocardiograms off antiarrhythmic drugs after excluding amiodarone users. Among them, 1213 subjects had genome-wide association study dataset analyzable for the Mendelian randomization. We explored the mechanistic relationships between QTc interval (ms) and the risk of a stroke by analyzing the Mendelian randomization (1213 subjects) after reviewing 35 genetic polymorphisms associated with the QTc in 31 European descent studies. @*Results@#Among the patients in the higher quartile with a higher QTc, CHA2DS2-VASc score (p < 0.001), and age (p < 0.001), the proportions of a prior stroke (p < 0.001), females, heart failure, and persistent AF were significantly higher than in those in the lower quartile. The QTc was independently associated with the CHA2DS2-VASc score (β, 4.63E−5; 95% confidence interval, 3.57E−6–8.90E−5; p = 0.034) and ischemic strokes (odds ratio, 1.01; 95% confidence interval, 1.00–1.01; p = 0.027). However, there was no direct causal relationship between the QTc and CHA2DS2-VASc score or a prior stroke in either the one-sample or two-sample Mendelian randomizations. @*Conclusion@#The QTc was independently associated with the CHA2DS2-VASc score and strokes among the patients with AF who underwent catheter ablation, despite no genetically direct causal relationship.