Exercise capacity and risk of incident atrial fibrillation in healthy adults

Background/Aims@#Atrial fibrillation (AF) is a common arrhythmia and is associated with cardiovascular morbidity and mortality. It is important to identify and control the modifiable risk factors of AF. We aimed to examine the association of exercise capacity with the risk of incident AF within 3 years in healthy subjects. @*Methods@#We evaluated asymptomatic adults who had undergone more than two consecutive health checkups. We included subjects who exhibited normal sinus rhythm on the first health examination and who developed AF on the second or subsequent health examinations. Subjects who underwent cardiopulmonary exercise testing within 3 years before the diagnosis of AF were examined. @*Results@#The study population in the analyses included 428 cases (mean age 58.4 ± 7.6 yr, male 95.6%). There were significant differences in maximal systolic blood pressure (SBP; case 169.4 ± 24.2 vs. control 173.9 ± 22.3 mmHg), peak VO2 (29.5 ± 5.4 vs. 30.4 ± 4.8 mL/kg per minute), and maximal metabolic equivalents (METs; 8.5 ± 1.6 vs. 8.7 ± 1.4) between the two groups. In the multivariable logistic models, adjusted odds ratios were 0.99 for maximal SBP (95% confidence interval [CI] 0.98–0.99), 0.97 for peak VO2 (95% CI 0.95–0.99), and 0.91 for maximal METs (95% CI 0.83–0.98). @*Conclusions@#We demonstrated that poorer exercise capacity was associated with the development of AF in a healthy population. A prospective, systematic trial is necessary to confirm that appropriate exercise training will be beneficial in preventing the development of AF in such patients.

Occurrence of Ischemic Stroke in Patients With Atrial Fibrillation Receiving Non-Vitamin K Oral Anticoagulants: Causes and Prevention Strategies / 대한뇌졸중학회지

Atrial fibrillation (AF) is a leading cause of cardioembolic stroke, which is often fatal or disabling. Prevention of stroke is crucial in AF management, and anticoagulation with non-vitamin K oral anticoagulants (NOACs) is the mainstay of AF management for stroke prevention. Because NOAC prescriptions have been surging worldwide, the development of acute ischemic stroke in patients with AF who receive NOAC treatment is an increasingly important issue in clinical practice. Moreover, these patients show a high risk of recurrence, with more than a 50% higher risk, than do patients with AF and no prior anticoagulation therapy. Careful evaluation is mandatory to determine possible causes of ischemic stroke during NOAC therapy. Differentiation of AF-unrelated stroke and demonstration of combined cardiac disease/systemic coagulopathy are important in these patients and may provide improved results in their treatment. In addition, ensuring appropriate dosing and good adherence to NOAC treatment is important. Cardioembolism, despite sufficient anticoagulation and no other causes, is the most common and challenging complication because switching to anticoagulants or adding antiplatelets to the treatment regimen does not reduce the risk of recurrent stroke, and there are no guidelines for this specific situation. This review article aimed to present the most updated data on the prevalence, causes, and secondary prevention strategies, specifically focusing on non-pharmacological approaches, together with relevant cases of AF in patients who developed ischemic stroke on NOAC therapy.

Totally Thoracoscopic Ablation in Patients With Recurrent Atrial Fibrillation After Catheter Ablation

Background@#The objective of this study was to evaluate the efficacy and safety of totally thoracoscopic ablation (TTA) in patients with recurrent atrial fibrillation (AF) after radiofrequency catheter ablation (RFCA). @*Methods@#From February 2012 to May 2020, 460 patients who underwent TTA were classified into two groups: CA (presence of RFCA history, n = 74) and nCA groups (absence of RFCA history, n = 386). Inverse probability of treatment weighting (IPTW) analyses were used to adjust for confounders. The primary endpoint was freedom from the composite of AF, typical atrial flutter, atypical atrial flutter and any atrial tachyarrhythmia, lasting more than 30 seconds during the follow-up. All patients were followed up at 3, 6, and 12 months via electrocardiogram and 24-hour Holter monitoring. @*Results@#Bilateral pulmonary vein isolation (PVI) was conducted in all patients and the conduction block tests were confirmed. In the CA group, difficult PVI occasionally occurred due to structural changes, such as pericardial adhesion and fibrosis of the pulmonary venous structure, caused by a previous catheter ablation. Early complications such as stroke and pacemaker insertion were not different between the two groups. The normal sinus rhythm was maintained in 70.1% (317/460) patients after a median follow-up period of 38.1 months.The IPTW-weighted Kaplan-Meier curves revealed that freedom from AF events at 5 years was 68.4% (95% confidence interval, 62.8–74.5) in the nCA group and 31.2% (95% confidence interval, 16.9–57.5) in the CA group (P < 0.001). In IPTW-weighted Cox regression, preoperative left atrial diameter, persistent or long-standing AF, the presence of congestive heart failure and catheter ablation history were associated with AF events. @*Conclusion@#Patients in the CA group showed a higher recurrence rate of AF than those in the nCA group, while TTA was safely performed in both the groups.

Rotational mechanical dilator sheaths for effective transvenous lead extraction

Background@#An exponential rise in clinical demand for cardiac implantable electronic device (CIED) therapy is observed all over the world due to the rapidly expanding lifespan. Accordingly, appropriate lead management including lead extraction is becoming increasingly essential components for the comprehensive care of patients with various CIEDs.Main body: With a high success rate and a low complication rate, transvenous lead extraction (TLE) has now been established as first-line therapy for lead extraction. However, TLE is often challenging when there are heavily calcified fibrous adhesions between leads and cardiovascular structures. Recently, rotational mechanical dilator (RMD) sheaths were introduced to resolve this issue and facilitate TLE procedure. There are two types of commercially available RMD sheaths, Evolution ® systems and TightRail™. Thorough knowledge of the proper use of the RMD devices is essential to increase success rate and to reduce complications of TLE. In the present review, mechanical features, various tech‑ niques, and clinical data of RMD sheaths will be described. @*Conclusion@#According to recent advancement of device technology, the clinical outcomes of TLE using the RMD sheaths are continuously improving. However, as the RMD sheath is a potentially aggressive tool, special care should be taken when used in patients with longer lead ages.

Catheter ablation of outflow tract ventricular arrhythmia with intracardiac echocardiography assistance

As the indications for catheter-based electrophysiologic procedures become more diverse and complex, accurate assessment of the anatomy of intracardiac structure has become essential for the optimal clinical outcome. Since intracardiac echocardiography (ICE) was first introduced in 1980, it has become an integral part of various electro‑ physiologic procedures enabling accurate visualization of cardiac structures and continuous monitoring of catheter position, with integration of real-time images and electroanatomic mapping. Catheter ablation for outflow tract ventricular arrhythmias (OTVAs) has been actively performed in symptomatic patients. However, the anatomic com‑ plexity of OT serves as the biggest obstacle to obtain the optimal results. In OTVAs, ICE has played an invaluable role in precisely defining the anatomic shell of OT beyond fluoroscopy and in guiding catheter manipulation in relation to critical structures like the conduction system and coronary arteries. This review article provides detailed information on comprehensive application of ICE for catheter ablation of OTVAs.

Effectiveness of the Early Staged Hybrid Approach for Treatment of Symptomatic Atrial Fibrillation: the Electrophysiology Study Could Be Deferred?

Background@#The efficacy of catheter ablation for persistent atrial fibrillation (AF) remains suboptimal. A hybrid approach of catheter ablation combined with totally thoracoscopic surgical ablation can improve outcomes. In this study, we evaluated the efficacy of the early staged hybrid procedure in hospital stay after totally thoracoscopic ablation compared to the stand-alone totally thoracoscopic ablation. @*Methods@#Patients who underwent totally thoracoscopic ablation from February 2012 to December 2018 were included in this study. We compared the outcomes of the totally thoracoscopic ablation only group versus the early staged hybrid procedure group. The primary outcome was recurrence of atrial tachyarrhythmia after three months of blanking period. The secondary outcome was repeated unplanned additional electrophysiology study and catheter ablation due to atrial tachyarrhythmia recurrence. @*Results@#A total of 306 patients (mean age, 56.8 ± 8.5 years; 278 [90.8%] males) was included in the study, with 81 patients in the early staged hybrid group and 225 patients in the standalone totally thoracoscopic ablation only group. The mean follow-up duration was 30.0 months. Overall arrhythmia-free survival showed no significant difference between the two groups (log-rank P = 0.402). There was no significant difference in the rate of repeat procedure between the two groups (log-rank = 0.11). @*Conclusion@#The early staged hybrid procedure after thoracoscopic ablation could not improve the outcome of recurrence of atrial tachyarrhythmia. The second stage of electrophysiology study could be deferred to patients with recurrence of atrial tachyarrhythmia during follow up after totally thoracoscopic ablation.

Long-term Clinical Outcomes of Radiofrequency Catheter Ablation versus Permanent Pacemaker Implantation in Patients with Tachycardia-Bradycardia Syndrome

Background and Objectives@#Pacemaker (PM) implantation is a well-accepted treatment option for patients with paroxysmal atrial fibrillation (AF) and related tachycardiabradycardia syndrome (TBS). Data on the long-term clinical outcomes after radiofrequency catheter ablation (RFCA) or PM implantation are sparse. @*Methods@#The medical records of 217 patients with TBS were retrospectively assessed.Outcomes in patients who underwent RFCA (n=108, 49.8%) were compared to those with PM implantation (n=109, 50.2%). The clinical outcomes were sinus rhythm maintenance, conversion to persistent AF, additional procedure or crossover, and the composite of cardiovascular hospitalization and death. @*Results@#During the follow-up period (mean 3.5±2.0 years), the RFCA group, compared to the PM group, showed better sinus rhythm maintenance (adjusted hazard ratio [aHR], 0.27;95% confidence interval [CI], 0.15–0.46; p=0.002) and less progression to persistent AF (aHR, 0.20; 95% CI, 0.06–0.63; p=0.006). Additional procedure or crossover did not differ significantly between the groups (aHR, 2.07; 95% CI, 0.71–6.06; p=0.185 and aHR, 0.69; 95% CI, 10.8–2.67; p=0.590, respectively). Most RFCA patients (92.6%) did not require pacemaker implantation during long term follow-up period (>3.5 years). The composite endpoint of cardiovascular rehospitalization and death was not significantly different between the groups (aHR, 0.92; 95% CI, 0.50–1.66; p=0.769).Background and Objectives: Pacemaker (PM) implantation is a well-accepted treatment option for patients with paroxysmal atrial fibrillation (AF) and related tachycardiabradycardia syndrome (TBS). Data on the long-term clinical outcomes after radiofrequency catheter ablation (RFCA) or PM implantation are sparse. @*Methods@#The medical records of 217 patients with TBS were retrospectively assessed.Outcomes in patients who underwent RFCA (n=108, 49.8%) were compared to those with PM implantation (n=109, 50.2%). The clinical outcomes were sinus rhythm maintenance, conversion to persistent AF, additional procedure or crossover, and the composite of cardiovascular hospitalization and death. @*Results@#During the follow-up period (mean 3.5±2.0 years), the RFCA group, compared to the PM group, showed better sinus rhythm maintenance (adjusted hazard ratio [aHR], 0.27;95% confidence interval [CI], 0.15–0.46; p=0.002) and less progression to persistent AF (aHR, 0.20; 95% CI, 0.06–0.63; p=0.006). Additional procedure or crossover did not differ significantly between the groups (aHR, 2.07; 95% CI, 0.71–6.06; p=0.185 and aHR, 0.69; 95% CI, 10.8–2.67; p=0.590, respectively). Most RFCA patients (92.6%) did not require pacemaker implantation during long term follow-up period (>3.5 years). The composite endpoint of cardiovascular rehospitalization and death was not significantly different between the groups (aHR, 0.92; 95% CI, 0.50–1.66; p=0.769). @*Conclusions@#RFCA is an effective alternative to PM implantation in patients with TBS.In these patients, successful RF ablation of AF is related to a higher rate of sinus rhythm maintenance compared to PM implantation, and the composite outcome of cardiovascular rehospitalization and death is similar.

Editorial: Simple Maneuver for Estimating the Depth of the Focal Activation Source in Myocardium

No abstract available.

Efficacy of Cardiac Resynchronization Therapy Using Automated Dynamic Optimization and Left Ventricular-only Pacing

BACKGROUND: Although device-based optimization has been developed to overcome the limitations of conventional optimization methods in cardiac resynchronization therapy (CRT), few real-world data supports the results of clinical trials that showed the efficacy of automatic optimization algorithms. We investigated whether CRT using the adaptive CRT algorithm is comparable to non-adaptive biventricular (BiV) pacing optimized with electrocardiogram or echocardiography-based methods. METHODS: Consecutive 155 CRT patients were categorized into 3 groups according to the optimization methods: non-adaptive BiV (n = 129), adaptive BiV (n = 11), and adaptive left ventricular (LV) pacing (n = 15) groups. Additionally, a subgroup of patients (n = 59) with normal PR interval and left bundle branch block (LBBB) was selected from the non-adaptive BiV group. The primary outcomes included cardiac death, heart transplantation, LV assist device implantation, and heart failure admission. Secondary outcomes were electromechanical reverse remodeling and responder rates at 6 months after CRT. RESULTS: During a median 27.5-month follow-up, there was no significant difference in primary outcomes among the 3 groups. However, there was a trend toward better outcomes in the adaptive LV group compared to the other groups. In a more rigorous comparisons among the patients with normal PR interval and LBBB, similar patterns were still observed. CONCLUSION: In our first Asian-Pacific real-world data, automated dynamic CRT optimization showed comparable efficacy to conventional methods regarding clinical outcomes and electromechanical remodeling.

2018 KHRS Guidelines for Catheter Ablation of Ventricular Arrhythmias: Part 1

Ventricular arrhythmias (VA) are a major cause of sudden cardiac death (SCD) in patients with known heart disease. Risk assessment and effective prevention of SCD are key issues in these patients. Implantable cardioverter defibrillator (ICD) insertion effectively treats sustained VA and reduces mortality in patients at high risk of SCD. Appropriate anti-arrhythmic drugs and catheter ablation reduce the VA burden and the occurrence of ICD shocks. In this guideline, authors have described the general examination and medical treatment of patients with VA. Medications and catheter ablation are also used as acute phase therapy for sustained VA.

2018 KHRS Guidelines for Catheter Ablation of Ventricular Arrhythmias: Part 2

The recommendations outlined constitute the first clinical practice guidelines of the Korean Heart Rhythm Society regarding catheter ablation of ventricular arrhythmias (VA). This is a guideline PART 2, which includes VA in the structurally normal heart, inherited primary arrhythmia syndromes, VA related to congenital heart disease, as well as VA and sudden cardiac death observed in specific populations. In the structurally normal heart, treatment is guided by the occurrence of symptoms or the frequency of arrhythmias that cause ventricular dysfunction over time. Catheter ablation can be recommended in patients in whom anti-arrhythmic medications are ineffective. The sites of origin of arrhythmic activity are known to be the outflow tract, fascicles, papillary muscle, or the annulus. Specific cardiac channelopathies include congenital long QT and Brugada syndrome. This guideline discusses the diagnostic criteria, risk stratification, and treatment of these syndromes. We have included recommendations for adult congenital heart disease. Moreover, we have discussed the management of VA occurring in specific populations such as in patients with psychiatric and neurological disorders, pregnant patients, those with obstructive sleep apnea or drug-related pro-arrhythmias, athletes, and elderly patients.

2018 KHRS Guidelines for Catheter Ablation of Ventricular Arrhythmias: Part 3

Treatment of ventricular arrhythmias (VA) usually involves managing the underlying cardiac conditions that cause the arrhythmia. However, managing the underlying disease is often challenging, and catheter ablation, or treatment targeting the VA itself might be required in a few patients. In this article, we explored evidence and recommendations regarding the treatment of VA in patients with structural heart disease focusing on the utilization of catheter ablation in these patients. The administration of optimal medical therapy, insertion of an implantable cardioverter-defibrillator, or resynchronization therapy improves survival in patients with left ventricular dysfunction. The role of catheter ablation in preventing sudden cardiac death remains uncertain in this population. In patients with coronary artery disease, reversing myocardial ischemia via revascularization is important in managing VA. Catheter ablation is recommended in patients with recurrent ventricular tachycardia in a setting of ischemic heart disease. In patients with non-ischemic cardiomyopathies such as dilated cardiomyopathy or hypertrophic cardiomyopathy, catheter ablation may be considered for those presenting with drug-refractory ventricular tachycardia.

Implantable Cardioverter-Defibrillator of Korean Patients in a Single Center Registry

BACKGROUND AND OBJECTIVES: The safety and efficacy of implantable cardioverter-defibrillator (ICD) for Korean is unclear. We investigated the clinical characteristics and outcomes of Korean patients undergoing ICD for primary or secondary prevention. MATERIALS AND METHODS: From October 1999 to December 2016, 396 cases (365 patients) of ICD implantation were performed: Baseline characteristics, procedural findings, and clinical outcome data were collected retrospectively from our ICD registry. The primary outcome was composite of cardiac death, appropriate shock or antitachycardia pacing. RESULTS: Among 365 patients, 91 patients (25.9%) had ICD for primary prevention and 274 patients (75.1%) were for secondary prevention (51.2±17.10 years, male was 80.8%). The median follow-up period was 3.1 years (interquartile range: 1.6–6.0 days). The most prevalent etiology was dilated cardiomyopathy (46.2%) in the primary prevention and idiopathic ventricular tachycardia or fibrillation (24.4%) in the secondary prevention. The primary outcome was noted in 28.6% of the primary prevention and 33.2% of the secondary prevention (P=0.44). The rate of cardiac death was 2.2% in the primary prevention and 1.8% in the secondary prevention (P=1.00). The hospitalization due to heart failure was higher in the primary prevention compared with the secondary prevention (23.1% versus 13.5%, P=0.03). ICD therapy occurred in 134 patients (36.7%). Among them, 60 patients (44.8% of ICD therapy) experienced inappropriate shock. The most common cause of inappropriate shock was atrial fibrillation of flutter (AF/AFL). CONCLUSION: The clinical efficacy and safety of ICD in Korean is consistent with the data from Western countries.

Interrelated Atrioventricular Reentrant Tachycardia and Idiopathic Left Ventricular Tachycardia in a Patient with Manifested Bystander Accessory Pathway

Double tachycardia is defined as the coexistence of supraventricular tachycardia (SVT) and ventricular tachycardia (VT). In clinical practice, incidentally encountered double tachycardia is difficult to diagnose during electrophysiology study without prior documentation of both tachycardias. SVT can be confused with VT because SVT sometimes show an aberrant conduction depending on heart rate. In the present case, a patient with Wolff-Parkinson-White syndrome exhibited atrioventricular reentrant tachycardia (AVRT) via a concealed bypass tract and idiopathic left ventricular tachycardia (ILVT), which were difficult to discriminate because of their similar cycle length and interrelationship.

The Incidence of Riata Defibrillator Lead Failure: a Single-Center Experience

Riata defibrillator leads were recalled due to a high failure rate. This study measured the incidence of externalized conductor (EC) and electrical dysfunction (ED) and sought to determine the predictors of ED with Riata defibrillator leads. We enrolled patients who received Riata® or Riata® ST silicone defibrillator leads at our center between January 2003 and December 2010. The presence of EC was evaluated with chest radiography. The incidence rates were measured at 5 years after lead implantation. We also investigated the rates of ED and other clinical events during the follow-up period. A total of 44 patients were analyzed. The total cumulative incidence of EC was 27.3%. During the median dwell time (80 months), the incidence of ED was 22.7%. Patients with ED were younger (46.5 vs. 56.5 years, P = 0.018) and had a higher prevalence of cardiomyopathy than those without ED (60.0% vs. 20.6%, P = 0.043). ECs were most frequently detected in patients who underwent X-ray analysis 3–5 years after lead implantation (44.4%). In contrast, ED had a bimodal incidence pattern, with peaks at 5 years (7.0%) and 9 years (5.3%). There was no difference in ED-free survival rate between patients with and without EC (P = 0.628). Given the delayed occurrence of EC and ED after implantation of Riata defibrillator leads, long-term close monitoring is critically important.

Comparison of De Novo versus Upgrade Cardiac Resynchronization Therapy; Focused on the Upgrade for Pacing-Induced Cardiomyopathy

PURPOSE: This study aimed to determine whether upgrade cardiac resynchronization therapy (CRT) shows better outcomes than de novo CRT. To do so, we compared the efficacy of CRT between de novo and upgrade groups, focusing particularly on the effect of upgrade CRT on patients with pacing-induced cardiomyopathy (PiCM). MATERIALS AND METHODS: PiCM was defined as new-onset dilated cardiomyopathy following pacemaker implantation in patients with baseline normal ejection fraction ≥50%. Electro-mechanical reverse remodeling and clinical outcomes were compared among the de novo (n=62), PiCM upgrade (n=7), and non-PiCM upgrade (n=8) CRT groups. RESULTS: The PiCM upgrade group showed significantly greater electro-mechanical reverse remodeling than the de novo CRT or non-PiCM upgrade groups at 6-month follow-up. The rate of super-responders was significantly higher in the PiCM upgrade group than the other CRT groups. The group factor of the PiCM upgrade was identified as an independent predictor of super-responder in multivariate analysis (odds ratio 10.4, 95% confidential interval 1.08–99.4, p=0.043). During the median follow-up of 15.8 months, the PiCM upgrade group showed the lowest rate of composite clinical outcomes, including cardiac death, heart transplantation, and heart failure-related rehospitalization (p=0.059). CONCLUSION: The upgrade CRT for PiCM patients showed better performance in terms of electro-mechanical reverse remodeling than de novo implantation or upgrade CRT in non-PiCM patients.

The Absence of Atrial Contraction as a Predictor of Permanent Pacemaker Implantation after Maze Procedure with Cryoablation

BACKGROUND: The absence of atrial contraction (AC) after the maze procedure has been reported to cause subsequent annular dilatation and to increase the risk of embolic stroke. We hypothesized that the lack of AC could increase the risk of permanent pacemaker (PPM) implantation in patients undergoing the maze procedure. METHODS: In 376 consecutive patients who had undergone a cryo-maze procedure and combined valve operation, recovery of AC was assessed at baseline and at immediate (≤2 weeks), early (≤1 year, 4.6±3.8 months), and late (>1 year, 3.5±1.1 years) postoperative stages. RESULTS: With a median follow-up of 53 months, 10 patients underwent PPM implantation. Seven PPM implants were for sinus node dysfunction (pauses of 9.6±2.4 seconds), one was for marked sinus bradycardia, and two were for advanced/complete atrioventricular block. The median (interquartile range) time to PPM implantation was 13.8 (0.5–68.2) months. Our time-varying covariate Cox models showed that the absence of AC was a risk factor for PPM implantation (hazard ratio, 11.92; 95% confidence interval, 2.52 to 56.45; p=0.002). CONCLUSION: The absence of AC may be associated with a subsequent risk of PPM implantation.

Complications of Cardiac Perforation and Lead Dislodgement with an MRI-Conditional Pacing Lead: a Korean Multi-Center Experience

Medtronic CapSureFix MRI 5086 pacing lead (5086; Medtronic, Inc., Minneapolis, MN, USA) has been reported to be associated with increased cardiac perforation and lead dislodgement. This study aimed to compare the incidence of cardiac perforation and lead dislodgement within 30 days after pacemaker implantation between 5086 MRI lead and previous Medtronic CapSureFix Novus 5076 non-MRI pacing lead. This was a nationwide, multicenter retrospective study in which we compared the incidence of adverse events between 277 patients implanted with 5086 lead and 205 patients implanted with 5076 lead between March 2009 and September 2014. Cardiac perforation within 30 days of pacemaker implantation occurred in 4 patients (1.4%) with the 5086 lead and in no patient with the 5076 lead (P = 0.084). Lead dislodgement occurred in 8 patients (2.9%) with the 5086 lead and in 5 patients (2.4%) with the 5076 lead (P = 0.764). On multivariate logistic regression analysis, age was significantly associated with cardiac perforation. Congestive heart failure and implantation of right atrial (RA) lead at RA free wall or septum were significant factors for the incidence of lead dislodgement and lead revision. The incidence of cardiac perforation and lead dislodgement were not statistically different between the patients with 5086 lead and the patients with 5076 lead. However, careful attention for cardiac perforation may be needed when using the 5086 MRI lead, especially in elderly patients.

The Persistence of Non-Vitamin K Antagonist Oral Anticoagulants in Korean Patients with Non-Valvular Atrial Fibrillation

BACKGROUND AND OBJECTIVES: Non-vitamin K antagonist oral anticoagulants (NOACs) are increasingly used for stroke prevention in patients with non-valvular atrial fibrillation (NVAF), showing better efficacy and safety than warfarin. However, the rates or reasons for discontinuation of NOACs in clinical practice have not been clarified. The aim of this study was to compare 3 NOACs (apixaban, rivaroxaban, and dabigatran) with warfarin in terms of medication persistence. SUBJECTS AND METHODS: We retrospectively evaluated 1,527 patients with NVAF who had recently started taking NOACs between January 2012 and September 2015 (294 apixaban, 748 rivaroxaban, and 485 dabigatran) and compared them with 363 patients with NVAF who started taking warfarin between January 2012 and December 2013 at the Samsung Medical Center. RESULTS: The mean follow-up duration was 532 days. The discontinuation rates were higher in the 3 NOAC groups than in the warfarin group within the first year. The major causes of discontinuation were maintenance of sinus rhythm; adverse events, including all bleeding and gastrointestinal symptoms; and patients demand. The adverse event rate was lower in the warfarin group than in the 3 NOAC groups. No significant differences in thromboembolic and major bleeding events were found between the 3 NOAC groups and the warfarin group. CONCLUSION: In a single-center study, NOACs showed lower medication persistence and higher adverse event rates than warfarin during the first year.

Radiofrequency Ablation of Recurrent Ventricular Premature Complex Originating from near Left Ventricular Summit Guided by Intracardiac Echocardiography

A 40-year-old man presented with frequent ventricular premature complexes (VPCs) and left ventricular systolic dysfunction. He underwent radiofrequency (RF) ablation using a 3-dimensional mapping system; the ablation was performed from both the right and left outflow tract septa. Improvement in symptoms and left ventricular systolic function was noted, but VPCs recurred one month after the procedure, and 24-hour Holter monitoring revealed a VPC burden of 26%. Direct visualization of the anatomical details, catheter contact, and transmural lesion formation by intracardiac echocardiography allowed for successful performance of a redo RF ablation with higher power and longer duration at the previous ablation sites.