Upper common pathway analysis using late atrial premature depolarization in atrioventricular nodal reentry tachycardia.

BACKGROUND: Anatomic and electrophysiologic findings suggest that the actual circuit of atrioventricular nodal reentrant tachycardia (AVNRT) involves the perinodal atrium. However, occasional instances in which the atrium is dissociated from the AVNRT have led to the concept of an upper common pathway (UCP). OBJECTIVE: We aimed to assess the prevalence of UCP in AVNRT using a late atrial premature depolarization (LAPD) maneuver. METHODS: Patients who were diagnosed with typical AVNRT by electrophysiologic studies were enrolled. For evaluation of the presence of UCP, an LAPD was given at the coronary sinus ostium (osCS) during AVNRT, and then pacing was repeated incrementally every 10 ms. Electrograms in the earliest retrograde atrial activation site (ERAS) near the proximal His were mapped and recorded during the pacing. Results were interpreted as follows: absence of UCP-an LAPD from the osCS can reset the tachycardia without depolarizing the ERAS; presence of UCP-an LAPD from the osCS can depolarize the ERAS without resetting the tachycardia; and indeterminate-an LAPD from the osCS either resets the ERAS and tachycardia simultaneously or does not reset both. RESULTS: The LAPD maneuver was performed in 126 patients with AVNRT. It demonstrated an absence of UCP in 121 (96.0%) patients and the presence of UCP in 3 (2.4%) patients; the result was indeterminate in 2 (1.6%) patients. CONCLUSION: The LAPD maneuver revealed that the presence of UCP is indicated in only rare cases of AVNRT. In most AVNRT cases, the atrium is involved in the reentry circuit.

Clinical impact of capsulectomy during cardiac implantable electronic device generator replacement: a prospective randomized trial.

BACKGROUND: The avascular capsule around the generator of the cardiac implantable electronic device (CIED) could be susceptible to bacterial colonization and source of infection. Capsulectomy during CIED generator replacement may be beneficial in preventing device infection, but there is a lack of evidence. METHODS: This prospective randomized trial, conducted from December 2013 to December 2019, included 195 patients divided equally into two groups. In the intervention group (n = 97), capsule removal was performed on the floor of the pocket, while it was not performed in the control group (n = 98). In both groups, swab culture was performed in the pocket. The primary outcome was the occurrence of device infection requiring pocket revision. RESULTS: A total of 195 patients were included (mean age 70.2 ± 13.6 years, 55.4% women), with an average follow-up period of 54.3 ± 28.9 months. Among 182 patients undergoing microbiological cultures of pockets, 19 (10.4%) were confirmed positive, and Staphylococcus species were identified most frequently. The primary outcome occurred in 4 (2.1%), and there was no significant difference between the two groups (3.1% vs. 1.0%, p = 0.606). Hematoma has occurred in 10 patients (3.1% vs. 7.1%, p = 0.338), one of them required wound revision. In multivariable analysis, the occurrence of hematoma was the only independent risk factor associated with device infection (HR 13.6, 95% CI 1.02-181.15, p = 0.048). CONCLUSIONS: In this long-term prospective study, capsulectomy during the replacement of the generator did not reduce the incidence of device infection. There was no association between bacterial colonization in the capsule around the generator and CIED infection.

Clinical outcomes with the use of sodium-glucose cotransporter-2 inhibitors in patients with atrial fibrillation and type 2 diabetes mellitus: a multi-centre, real-world cohort study.

AIMS: Sodium-glucose cotransporter-2 inhibitors (SGLT2is) have been shown to improve cardiovascular outcomes and reduce the incidence of atrial fibrillation (AF) in patients with type 2 diabetes mellitus (T2DM). We investigated the clinical outcomes with and without the use of SGLT2is in patients with T2DM and concomitant AF. METHODS AND RESULTS: We derived patient data from a clinical data warehouse constructed from the electronic medical records of seven medical centres. Data for 11 012 patients diagnosed with both AF and T2DM were analysed. New SGLT2i users were classified into the SGLT2i group and those who were not prescribed SGLT2is were classified into the control group. We performed a 1:2 propensity score (PS)-matching analysis. The primary endpoint was a composite of all-cause death or hospitalization due to heart failure (HF) events in 3 years. The PS-matched population consisted of 1115 patients in the SGLT2i group and 2050 patients in the control group. Incidence of the primary endpoint was significantly lower in the SGLT2i group [8.4 vs. 14.6%, hazard ratio (HR) 0.69, 95% confidence interval (CI) 0.55-0.87]. Sodium-glucose cotransporter-2 inhibitors use was associated with significantly lower all-cause mortality (HR 0.43, 95% CI 0.29-0.67) and HF hospitalization (HR 0.77, 95% CI 0.59-0.99). Adverse renal events, defined as >50% increase in serum creatinine level or initiation of dialysis, occurred less often in the SGLT2i group (HR 0.50, 95% CI 0.38-0.66, P < 0.001). CONCLUSION: Use of SGLT2is in patients with T2DM and concomitant AF was associated with reduced mortality or HF hospitalization events.

In this multi-centre, registry-based analysis, the new use of sodium-glucose cotransporter-2 inhibitors (SGLT2is) in patients with atrial fibrillation and type 2 diabetes mellitus was associated with lower all-cause mortality or hospitalization due to heart failure (HF) events. All-cause mortality, HF hospitalization, ischaemic stroke, and composite renal outcomes, defined as >50% decline in renal function or new initiation of dialysis occurred significantly less in the SGLT2i new users, compared with the propensity score-matched controls. The difference in outcomes between the SGLT2i group and control group was more pronounced in patients with higher HbA1c at baseline and prior HF.

Effectiveness of Early Direct Oral Anticoagulant Monotherapy within One Year of Coronary Stent Implantation in Patients with Atrial Fibrillation: A Nationwide Population-Based Study.

We evaluated the effectiveness of early direct oral anticoagulant (DOAC) monotherapy within one year after percutaneous coronary intervention (PCI) in patients with atrial fibrillation (AF) using Korean National Health Insurance Service data. AF patients who underwent PCI were included and divided into the DOAC monotherapy group and the combination therapy group (DOAC with an antiplatelet agent) based on the medications used at 6 months after PCI. A major adverse cardiovascular event (MACE) was defined as a composite of cardiovascular death, acute myocardial infarction (AMI), stroke, or systemic thromboembolic event between 6 and 12 months after PCI. In the overall study population, the DOAC dose reduction rate was high in both the monotherapy group (70.8%) and the combination therapy group (79.1%). After propensity score matching, the MACE incidence was not significantly different between the two groups (hazard ratio [HR] 1.42 [0.90-2.24]). The numerical trend for higher MACE in the monotherapy group was mainly driven by the difference in stroke incidence (HR 1.84 [0.97-3.46]). All-cause death (HR 1.29 [0.61-2.74] or the incidence of major bleeding (HR 1.07 [0.49-2.35]) results were similar in the two groups. In conclusion, early DOAC monotherapy was not significantly associated with MACE risk between 6 and 12 months after PCI.

Identification of concealed cardiomyopathy using next-generation sequencing-based genetic testing in Korean patients initially diagnosed with idiopathic ventricular fibrillation.

AIMS: Idiopathic ventricular fibrillation (IVF) is a disease in which the cause of ventricular fibrillation cannot be identified despite comprehensive clinical evaluation. This study aimed to investigate the clinical yield and implications of genetic testing for IVF. METHODS AND RESULTS: This study was based on the multi-centre inherited arrhythmia syndrome registry in South Korea from 2014 to 2017. Next-generation sequencing-based genetic testing was performed that included 174 genes previously linked to cardiovascular disease. A total of 96 patients were clinically diagnosed with IVF. The mean age of the onset was 41.2 ± 12.7 years, and 79 patients were males (82.3%). Of these, 74 underwent genetic testing and four (5.4%) of the IVF probands had pathogenic or likely pathogenic variants (each having one of MYBPC3, MYH7, DSP, and TNNI3). All pathogenic or likely pathogenic variants were located in genes with definite evidence of a cardiomyopathy phenotype, either hypertrophic cardiomyopathy or arrhythmogenic right ventricular cardiomyopathy. CONCLUSION: Next-generation sequencing-based genetic testing identified pathogenic or likely pathogenic variants in 5.4% of patients initially diagnosed with IVF, suggesting that genetic testing with definite evidence genes of cardiomyopathy may enable molecular diagnosis in a minority of patients with IVF. Further clinical evaluation and follow-up of patients with IVF with positive genotypes are needed to unveil concealed phenotypes, such as the pre-clinical phase of cardiomyopathy.

Comparison of the 11-Day Adhesive ECG Patch Monitor and 24-h Holter Tests to Assess the Response to Antiarrhythmic Drug Therapy in Paroxysmal Atrial Fibrillation.

Accurate assessment of the response to the antiarrhythmic drug (AAD) in atrial fibrillation (AF) is crucial to achieve adequate rhythm control. We evaluated the effectiveness of extended cardiac monitoring using an adhesive ECG patch in the detection of drug-refractory paroxysmal AF. Patients diagnosed with paroxysmal AF and receiving AAD therapy were enrolled. The subjects simultaneously underwent 11-day adhesive ECG patch monitoring and a 24-h Holter test. The primary study outcome was a detection rate of drug-refractory AF or atrial tachycardia (AT) lasting ≥30 s. A total of 59 patients were enrolled and completed the study examinations. AF or AT was detected in 28 (47.5%) patients by an 11-day ECG patch monitor and in 8 (13.6%) patients by a 24-h Holter test (p < 0.001). The 11-day ECG patch monitor identified an additional 20 patients (33.8%) with drug-refractory AF not detected by the 24-h Holter, and as a result, the treatment plan was changed in 11 patients (10 catheter ablations, one medication change). In conclusion, extended cardiac rhythm monitoring using an adhesive ECG patch in patients with paroxysmal AF under AAD therapy led to over a threefold higher detection of drug-refractory AF episodes, compared to the 24-h Holter test.

Clinical and Genetic Features of Korean Inherited Arrhythmia Probands.

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.

Comparing the Efficacy of Carvedilol and Flecainide on the Treatment of Idiopathic Premature Ventricular Complexes from Ventricular Outflow Tract: A Multicenter, Randomized, Open-Label Pilot Study.

The mechanism of premature ventricular complexes (PVC) occurring in the ventricular outflow tract (OT) is related to an intracellular calcium overload and delayed afterdepolarizations that lead to triggered activity. The guidelines recommend using beta-blockers and flecainide for idiopathic PVCs, but they also acknowledge the limited evidence supporting this recommendation. We conducted a multicenter, randomized, open-label pilot study comparing the effect of carvedilol and flecainide on OT PVC, which are widely used to treat this arrhythmia. Patients with a 24 h Holter recording a PVC burden ≥ 5%, which showed positive R waves in leads II, III, and aVF, and without structural heart disease were enrolled. They were randomly assigned to the carvedilol or flecainide group, and the maximum tolerated dose was administered for 12 weeks. A total of 103 participants completed the protocol: 51 with carvedilol and 52 with flecainide. After 12 weeks of treatment, the mean PVC burden significantly decreased in both groups: 20.3 ± 11.5 to 14.6 ± 10.8% with carvedilol (p < 0.0001) and 17.1 ± 9.9 to 6.6 ± 9.9% with flecainide (p < 0.0001). Both carvedilol and flecainide effectively suppressed OT PVCs in patients without structural heart disease, with flecainide showing a superior efficacy compared to carvedilol.

Outcomes of On-Label Reduced-Dose Edoxaban in Patients With Atrial Fibrillation: The LEDIOS Registry.

BACKGROUND: Non-vitamin K antagonist oral anticoagulants (NOACs) are effective in preventing thromboembolisms and reduce the risk of bleeding compared with warfarin. There are few reports on the outcomes of on-label reduced-dose NOACs. The aim of this study was to assess the safety and efficacy of on-label reduced-dose edoxaban in patients with atrial fibrillation (AF). METHODS: This study is a multi-center, prospective, non-interventional study to evaluate the safety and efficacy of on-label reduced-dose edoxaban in patients with AF. We evaluated outcomes of major bleeding, stroke or systemic embolism, all-cause death, and composite clinical outcomes. RESULTS: A total of 2,448 patients (mean age 75.0 ± 8.3 years, 801 [32.7%] males) was included in the present study. The mean CHA2DS2-VASc score was 3.7 ± 1.5. Major bleeding events occurred at a rate of 1.34%/yr. The event rate of strokes and systemic embolisms was 1.13%/yr. The overall net clinical outcomes occurred at a rate of 3.19%/yr. There were no significant differences according to the number of dose reduction criteria, renal dysfunction, or body weight. Higher HAS-BLED score and higher combination of CHA2DS2-VASc and HAS-BLED score was associated with an increased risk of composite clinical outcomes compared to the lower score groups. CONCLUSIONS: This study was the largest prospective real-world study to investigate the safety and efficacy of on-label low-dose edoxaban in an Asian population. Reduced-dose edoxaban can be used safely in patients with severe renal dysfunction or extremely low body weight. Our observation suggests that physicians should consider bleeding risk even in a low-dose regimen. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03554837.

Clinical Usefulness of Virtual Ablation Guided Catheter Ablation of Atrial Fibrillation Targeting Restitution Parameter-Guided Catheter Ablation: CUVIA-REGAB Prospective Randomized Study.

BACKGROUND AND OBJECTIVES: We investigated whether extra-pulmonary vein (PV) ablation targeting a high maximal slope of the action potential duration restitution curve (Smax) improves the rhythm outcome of persistent atrial fibrillation (PeAF) ablation. METHODS: In this open-label, multi-center, randomized, and controlled trial, 178 PeAF patients were randomized with 1:1 ratio to computational modeling-guided virtual Smax ablation (V-Smax) or empirical ablation (E-ABL) groups. Smax maps were generated by computational modeling based on atrial substrate maps acquired during clinical procedures in sinus rhythm. Smax maps were generated during the clinical PV isolation (PVI). The V-Smax group underwent an additional extra-PV ablation after PVI targeting the virtual high Smax sites. RESULTS: After a mean follow-up period of 12.3±5.2 months, the clinical recurrence rates (25.6% vs. 23.9% in the V-Smax and the E-ABL group, p=0.880) or recurrence appearing as atrial tachycardia (11.1% vs. 5.7%, p=0.169) did not differ between the 2 groups. The post-ablation cardioversion rate was higher in the V-Smax group than E-ABL group (14.4% vs. 5.7%, p=0.027). Among antiarrhythmic drug-free patients (n=129), the AF freedom rate was 78.7% in the V-Smax group and 80.9% in the E-ABL group (p=0.776). The total procedure time was longer in the V-Smax group (p=0.008), but no significant difference was found in the major complication rates (p=0.497) between the groups. CONCLUSIONS: Unlike a dominant frequency ablation, the computational modeling-guided V-Smax ablation did not improve the rhythm outcome of the PeAF ablation and had a longer procedure time. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02558699.

The advantage of the mini-electrode-equipped catheter for the radiofrequency ablation of paroxysmal supraventricular tachycardia.

INTRODUCTION: Novel ablation catheters equipped with mini-electrodes (ME) offer high resolution mapping for target tissue. This study aimed to evaluate the mapping performance and efficacy of ME catheters in radiofrequency ablation (RFA) of paroxysmal supraventricular tachycardias (PSVTs). METHODS: We prospectively enrolled 136 patients undergoing RFA of PSVT including 76 patients with atrioventricular nodal reentrant tachycardia (AVNRT) and 60 patients with atrioventricular reentrant tachycardia (AVRT) or Wolff-Parkinson-White (WPW) syndrome. Patients were randomized to the ME group (ablation using ME catheters) or the control group (ablation using conventional catheters). The number of ablation attempt and cumulative ablation time to ablation endpoints, which was defined as an emergence of junctional rhythm in AVNRT or accessory pathway (AP) block in AVRT/WPW syndromes were compared. RESULTS: During ablation procedures, discrete slow pathway or AP electrograms were found in 27 (39.7%) patients in the ME group and 13 (19.1%) patients in the control group. The primary study outcomes were significantly lower in the ME group (ablation attempt number: 2.0 [1-4] vs. 3.0 [2-7] in the ME and control group, p = .032; ablation time: 23.5 [5.0-111.5] vs. 64.5 [16.0-185.0] s, p = .013). According to the PSVT diagnosis, ablation time to junctional rhythm was significantly shorter in the ME group in AVNRT. In AVRT/WPW syndrome, both ablation attempt number and ablation time to AP block were nonsignificantly lower in the ME group. CONCLUSION: The novel ME catheter was advantageous for identifying pathway potentials and reducing initial ablation attempt number and ablation time to reach acute ablation endpoint for PSVTs (ClinicalTrials.gov number, NCT04215640).

Edoxaban-based long-term antithrombotic therapy in patients with atrial fibrillation and stable coronary disease: Rationale and design of the randomized EPIC-CAD trial.

BACKGROUND: Anticoagulants are the standard therapy for patients with atrial fibrillation (AF) and antiplatelet therapy for those with coronary artery disease (CAD). However, compelling clinical evidence is still lacking regarding the long-term maintenance strategy with the combination of anticoagulant and antiplatelet drugs in patients with AF and stable CAD. DESIGN: The EPIC-CAD trial is an investigator-initiated, multicenter, open-label randomized trial comparing the safety and efficacy of 2 antithrombotic strategies in patients with high-risk AF (CHA2DS2-VASc score ≥ 2 points) and stable CAD (≥6 months after revascularization for stable angina or ≥12 months for acute coronary syndrome; or medical therapy alone). Patients (approximately N = 1,038) will be randomly assigned at a 1:1 ratio to (1) monotherapy with edoxaban (a non-vitamin K antagonist oral anticoagulant) or (2) combination therapy with edoxaban plus a single antiplatelet agent. The primary endpoint is the net composite outcome of death from any cause, stroke, systemic embolism, myocardial infarction, unplanned revascularization, and major or clinically relevant nonmajor bleeding at 1 year after randomization. RESULTS: As of December 2021, approximately 901 patients had been randomly enrolled over 2 years at 18 major cardiac centers across South Korea. The completed enrollment is expected at the mid-term of 2022, and the primary results will be available by 2023. CONCLUSIONS: EPIC-CAD is a large-scale, multicenter, pragmatic design trial, which will provide valuable clinical insight into edoxaban-based long-term antithrombotic therapy in patients with high-risk AF and stable CAD.

Single direct oral anticoagulant therapy in stable patients with atrial fibrillation beyond 1 year after coronary stent implantation.

OBJECTIVE: Optimal antithrombotic therapy in patients with atrial fibrillation (AF) beyond 1 year after coronary stent implantation has not been well established in the era of direct oral anticoagulant (DOAC). METHODS: Using Korean National Health Insurance Service data, we analysed 4294 patients with AF who were prescribed DOAC beyond 1 year after coronary stent implantation. Subjects were classified into the monotherapy group (DOAC single therapy, n=1221) or the combination therapy group (DOAC with an antiplatelet agent, n=3073). The primary ischaemic endpoint was defined as a composite of cardiovascular death, myocardial infarction, stroke or systemic thromboembolism. The secondary endpoints were all-cause death, major bleeding defined as a bleeding event requiring hospitalisation and net adverse clinical events. Propensity score matching was performed to balance baseline covariates. RESULTS: Among included patients, 94% had drug-eluting coronary stents. During a median follow-up of 19 (7-32) months, the monotherapy group had a similar risk of the primary ischaemic endpoint (HR 0.828, 95% CI 0.660 to 1.038) and all-cause death (HR 1.076, 95% CI 0.895 to 1.294) compared with the combination therapy group. Risk of major bleeding was lower in the monotherapy group (HR 0.690, 95% CI 0.481 to 0.989), which was mostly driven by reduced gastrointestinal bleeding (HR 0.562, 95% CI 0.358 to 0.883). There was no significant difference in net adverse clinical events between the two groups. CONCLUSIONS: DOAC monotherapy showed similar efficacy in preventing ischaemic events and was associated with lower major bleeding events compared with combination therapy in patients with AF beyond 1 year after coronary stent implantation.

Patient perception and treatment convenience of dabigatran versus vitamin K antagonist when used for stroke prophylaxis in atrial fibrillation: Real-world Evaluation of Long-term Anticoagulant Treatment Experience (RE-LATE) study.

PURPOSE: Dabigatran is a direct thrombin inhibitor approved for stroke prophylaxis in patients with non-valvular atrial fibrillation (NVAF). Real-world data about patient preference, satisfaction and convenience in patients in Asia are not available. The study aimed to explore the perception of patients with newly diagnosed NVAF regarding dabigatran versus vitamin K antagonists (VKAs), when used for stroke prevention. PATIENTS AND METHODS: This was a multinational, multicentre, non-interventional study involving 49 sites across 5 countries in South East Asia and South Korea where 934 patients newly diagnosed with NVAF were initiated on either dabigatran (N=591) or VKA (N=343). Data were collected at baseline and over two follow-up visits across 6 months. Treatment satisfaction and patient convenience were evaluated using the Perception on Anticoagulant Treatment Questionnaire-2 (PACT-Q2). RESULTS: The mean age of the patients was 65.9±10.4 years, and 64.2% were male. Mean CHA2DS2-VASc score was 2.4±1.5, and mean HAS-BLED score was 1.2±0.9. At baseline, patients initiated on dabigatran had higher stroke risk, bleeding risk, creatinine clearance and proportion of patients with concomitant illnesses compared with patients initiated on VKAs. Treatment convenience was perceived to be significantly better with dabigatran versus VKAs at visits 2 and 3 (p=0.0423 and 0.0287, respectively). Treatment satisfaction was significantly better with dabigatran compared with VKAs at visit 3 (p=0.0300). CONCLUSION: In this study, dabigatran is associated with better patient perception in terms of treatment convenience and satisfaction compared with VKAs when used for stroke prevention in newly diagnosed NVAF patients from South East Asia and South Korea. TRIAL REGISTRATION NUMBER: NCT02849509. PLAIN LANGUAGE SUMMARY: Patient satisfaction with dabigatran versus VKAs in South East Asia. Patients with atrial fibrillation are at high risk of stroke and require anticoagulants for stroke prevention. Two such anticoagulants are dabigatran and VKAs. We wanted to compare the extent of satisfaction and treatment convenience among newly diagnosed patients with atrial fibrillation from the South East Asian region when they were given either dabigatran or VKAs. Consenting patients filled out a standardised questionnaire called the PACT-Q2 over three visits after they were started on either dabigatran (591 patients) or VKAs (343 patients). We found that satisfaction and convenience were significantly higher when patients received dabigatran than when they received VKAs.