Clinical implications of combined glucose intolerance in treatment-naïve hypertensive patients.

BACKGROUND: This study is the first study to evaluate clinical significance of combined glucose intolerance (CGI) in treatment-naïve hypertensive patients. METHODS: We compared the results of demographic, anthropometric, clinical, laboratory examinations, echocardiography, arterial stiffness, central blood pressure (BP) and ambulatory BP monitoring (ABPM) between the groups according to fasting blood sugar (FBS), postprandial 2 hour blood glucose (PP2) and gender in treatment-naïve hypertensive patients. A total of 376 concecutively-eligible patients were categorized as follows: (1) normal glucose tolerance (NGT); FBS<100 mg/dL and PP2 < 140 (2) isolated glucose intolerance (IGI); 100≤FBS<126 or 140≤PP2 < 200, but not both 100≤FBS<126 and 140≤PP2 < 200 (3) CGI; both 100≤FBS<126 and 140≤PP2 < 200. RESULTS: Males were divided into NGT (n = 58, 33.1%), IGI (n = 88, 50.3%), CGI (n = 29, 16.6%) and females were divided into NGT (n = 59, 43.1%), IGI (n = 48, 35%), CGI (n = 30, 21.9%). In males multivariate analyses revealed that mitral average E/Ea (IGI vs CGI, p = 0.022), brachial-ankle pulse wave velocity baPWV(Rt.) (IGI vs CGI, p = 0.026), baPWV(Lt.) (IGI vs CGI, p = 0.018), office systolic BP (SBP) (NGT vs. CGI, p = 0.005; IGI vs. CGI, p = 0.001), office diastolic BP (DBP) (NGT vs. CGI, p = 0.034; IGI vs. CGI, p = 0.019), night-time SBP (NGT vs. CGI, p = 0.049; IGI vs. CGI, p = 0.018) were significantly higher in the CGI group than in the NGT or IGI group. However, there were no significant differences between the female groups. CONCLUSIONS: Treatment-naïve hypertensive males with CGI revealed subclinical diastolic dysfunction, arterial stiffness, and BPs.

Impact of Postprocedural TIMI Flow on Long-Term Clinical Outcomes in Patients with Acute Myocardial Infarction.

This study aimed to evaluate the clinical prognostic implications of postprocedural Thrombolysis in Myocardial Infarction (TIMI) flow in acute myocardial infarction patients. A total of 2796 ST-elevation myocardial infarction (STEMI) and 1720 non ST-elevation myocardial infarction (NSTEMI) patients treated in 8 hospitals affiliated with the Catholic University of Korea and Chonnam National University Hospital were analyzed. The study populations were divided according to the final TIMI flow. The primary outcome were the major adverse cardiac events (MACE), defined as a composite of cardiac deaths (CD), nonfatal myocardial infarctions (MI), and target lesion revascularization (TLR). Over a median follow-up of 3.3 years (minimum 2 to maximum 5 years), MACE and CD occurred more frequently in STEMI patients with TIMI ≤ 2 group than those with TIMI 3 (MACE: adjusted hazard ratio [aHR], 1.962; 95% confidence interval [CI] 1.513 to 2.546, P < 0.001, CD: aHR, 3.154, CI 2.308 to 4.309, P < 0.001). However, there was no significant difference between the two subgroups in NSTEMI (aHR, 0.932; 95% CI 0.586 to 1.484, P = 0.087). In STEMI patients, good postprocedural TIMI flow after PCI was associated with favorable clinical outcomes. And the effect of poor TIMI flow in STEMI was on death, not the components of MACE. Meanwhile, postprocedural TIMI flow had no effect on long-term outcomes in NSTEMI patients.

Epidemiology and outcomes in out-of-hospital cardiac arrest: a report from the NEDIS-based cardiac arrest registry in Korea.

Sudden cardiac death (SCD) is a significant issue affecting national health policies. The National Emergency Department Information System for Cardiac Arrest (NEDIS-CA) consortium managed a prospective registry of out-of-hospital cardiac arrest (OHCA) at the emergency department (ED) level. We analyzed the NEDIS-CA data from 29 participating hospitals from January 2008 to July 2009. The primary outcomes were incidence of OHCA and final survival outcomes at discharge. Factors influencing survival outcomes were assessed as secondary outcomes. The implementation of advanced emergency management (drugs, endotracheal intubation) and post-cardiac arrest care (therapeutic hypothermia, coronary intervention) was also investigated. A total of 4,156 resuscitation-attempted OHCAs were included, of which 401 (9.6%) patients survived to discharge and 79 (1.9%) were discharged with good neurologic outcomes. During the study period, there were 1,662,470 ED visits in participant hospitals; therefore, the estimated number of resuscitation-attempted CAs was 1 per 400 ED visits (0.25%). Factors improving survival outcomes included younger age, witnessed collapse, onset in a public place, a shockable rhythm in the pre-hospital setting, and applied advanced resuscitation care. We found that active advanced multidisciplinary resuscitation efforts influenced improvement in the survival rate. Resuscitation by public witnesses improved the short-term outcomes (return of spontaneous circulation, survival admission) but did not increase the survival to discharge rate. Strategies are required to reinforce the chain of survival and high-quality cardiopulmonary resuscitation in Korea.

Impact of left anterior line on left atrial appendage contractility in patients who underwent catheter ablation for chronic atrial fibrillation.

BACKGROUND: Left anterior line (LAL) has been used as a substitute for mitral isthmus line for catheter ablation of chronic atrial fibrillation (AF). However, it results in left anterolateral conduction delay and might affect left atrial (LA) contractility. We aimed to investigate whether LAL decreases LA appendage function. METHODS: This study included 46 patients (30 men, mean age 58 ± 9 years, group 1) with persistent AF who underwent catheter ablation including LAL. Thirty patients with paroxysmal AF who received no additional LA ablation were compared as control group (21 males, mean age 56 ± 8 years, group 2). Transthoracic and transesophageal echocardiography with Doppler tissue imaging was performed in sinus rhythm before and after the ablation. We compared the following variables: (1) E/A ratio of the mitral flow velocity, (2) ratio of early mitral inflow and mitral septal annulus velocity (E/Em), (3) peak velocity of appendage outflow (ApVmax), and (4) time delay from QRS onset to appendage outflow (TDqa). RESULTS: LA diameter was significantly reduced after ablation in both groups. In group 1, parameters for diastolic function (E/A ratio, 1.7 ± 0.5 vs 2.0 ± 0.6, P = 0.197; E/Em, 11.7 ± 4.8 vs 11.6 ± 5.1, P = 0.883) and appendage flow (ApVmax, 55.2 ± 19.9 cm/s vs 50.3 ± 19.3 cm/s, P = 0.203; TDqa, -77.3 ± 30.1 ms vs -66.1 ± 60.8 ms, P = 0.265) did not change significantly after ablation. Changes of ApVmax and TDqa after ablation were not significantly different between two groups (P = 0.409 and P = 0.195, respectively). CONCLUSIONS: LAL ablation did not aggravate mitral flow pattern or change appendage outflow. LAL could be used without concern over worsening LA diastolic and appendage function.

Prevalence of electrocardiographic findings suggestive of sudden cardiac death risk in 10,867 apparently healthy young Korean men.

BACKGROUND: The objective of this study was to determine the prevalence of electrocardiographic (ECG) findings suggestive of sudden cardiac death risk in apparently healthy young Korean men. METHODS: We administered questionnaires that elicited personal and family histories and performed ECGs on 10,867 male subjects (mean age, 20.9 years). The subjects with abnormal ECG findings underwent echocardiography, a treadmill test, Holter monitoring, a flecainide provocation test, or an electrophysiologic study (EPS) according to the ECG findings and histories. RESULTS: Of the subjects, 5.95% had left ventricular hypertrophy on ECG, but no subjects had hypertrophic cardiomyopathy by echocardiography. The percentage of subjects with a Brugada ECG pattern was 0.90%. We identified one subject with a positive result on the flecainide provocation test. The percentage of subjects with a preexcitation ECG was 0.17%. In two of the subjects, supraventricular tachycardia was induced in the EPS. Of the subjects, 0.05% had epsilon waves, but there were no subjects with arrhythmogenic right ventricular dysplasia/cardiomyopathy by echocardiography. The percentage of subjects with long QT intervals was 0.02%, but there were no arrhythmias on the treadmill test or Holter monitoring. CONCLUSIONS: The prevalence of a Brugada ECG pattern in apparently healthy young men is higher in Korea than other countries.

Relationship between resting electrocardiographic parameters and estimated 10-year risk for coronary heart disease in healthy adults in the USA.

BACKGROUND: Little is known about the relationship between resting electrocardiogram (ECG) parameters and the incidence of coronary heart disease (CHD). We sought to establish the association between ECG parameters and estimated 10-year risk for CHD. METHODS: We applied the risk prediction algorithm used by the National Cholesterol Education Program Adult Treatment Panel III guidelines to data from 6399 individuals in the Third National Health and Nutrition Examination Survey (aged 40-79 years) who had sinus rhythm, no previous heart disease, and no evidence of prior myocardial infarction according to the 12-lead Minnesota Code. We used multiple linear and logistic regression models to determine the relationship between 10-year risk for CHD and levels of resting ECG parameters. RESULTS: After adjusting for age, gender, race, and body mass index, individuals with high risk had higher heart rate (HR), left ventricular mass index (LVMI), and cardiac infarction injury score (CIIS), and longer HR-corrected QT (QTc) interval than those with low risk. In models fully adjusted for coronary risk factors, individuals in the highest quintile of HR, PR, and QTc interval were 2.2, 0.7, and 1.8 times, respectively, more likely to have a high 10-year risk as those in the lowest quintiles. There are dose-dependent associations between HR, LVMI, CIIS, and QTc interval and the 10-year risk group. CONCLUSIONS: These findings indicate that high HR, LVMI, and CIIS and prolonged QTc interval are positively and prolonged PR interval is negatively associated with high 10-year risk for CHD in a general population.

The significance of repetitive ventricular responses induced by radiofrequency energy application for idiopathic left ventricular tachycardia.

In radiofrequency (RF) ablation for idiopathic left ventricular tachycardia (ILVT), the termination of tachycardia during RF ablation is considered a hallmark of success. However, in cases of patients with difficulty of induction of ventricular tachycardia (VT), the evaluation of procedural success can be problematic. We have observed thermal responses reflected as ventricular rhythm change to RF energy delivered on sinus rhythm for ILVT. We therefore describe the significance of repetitive ventricular responses. The study subjects were 11 ILVT patients for whom RF energy was delivered during sinus rhythm because of difficulty in re-induction of tachycardia. During each energy delivery, we focused on the occurrence of repetitive ventricular responses especially exhibiting a similar morphology to clinical VT. The repetitive ventricular responses were noted in 10 of 11 patients. Two patients received a second procedure due to the recurrence of ILVT. The mean follow-up period was 36.2+/-12.8 months. The clinical course of the remaining patients was favorable and without recurrence of ILVT. Based on the favorable clinical outcomes, ablation-induced repetitive ventricular responses with similar QRS morphology to clinical ILVT are useful markers for selecting an ablation site and could be used as an additional mapping method, termed as "thermal mapping".

Acute changes in cardiac synchrony and output according to RV pacing sites in Koreans with normal cardiac function.

INTRODUCTION: The synchrony of the pacing heart can be affected by the right ventricular (RV) pacing site and is crucial to cardiac function in pacemaker recipients. We evaluated the acute changes in cardiac synchrony according to the RV pacing sites in normal systolic functioning subjects with normal QRS. METHODS: We conducted this study with 30 patients with the pacing in the RV apex (RVA), RV septum (RVS), and RV outflow tract (RVOT) in a sequential manner. Transthoracic echocardiography was conducted at rest and during pacing in order to measure interventricular and intraventricular dyssynchrony in all patients. RESULTS: QRS duration (148.1 +/- 12.8 ms) of RVA pacing was significantly shorter than that of RVS pacing (154.4 +/- 14.1 ms, P < 0.01) and RVOT pacing (160.6 +/- 15.7 ms, P < 0.001). We noted no statistically significant difference in cardiac output according to the pacing sites. The interventricular dyssynchrony with M-mode and Doppler echocardiography in RVOT pacing was increased to an insignificant degree as compared with those with RVS pacing or RVA pacing. The intraventricular dyssynchrony with tissue Doppler echocardiography in RVA pacing was reduced significantly as compared with that of RVS pacing or RVOT (RVA = 60.3 +/- 32.7 ms, RVS = 82.1 +/- 33.8 ms, RVOT = 79.1 +/- 33.3 ms; RVA vs RVS = P < 0.05, RVA vs RVOT = P < 0.01, RVS vs RVOT = P = NS). CONCLUSION: RVA pacing is superior to RVS and RVOT pacing with regard to intraventricular synchrony in normal systolic functioning subjects with normal QRS. Cardiac output at RVA pacing is not inferior to other sites.

Outcomes of Direct Oral Anticoagulants in Patients With Mitral Stenosis.

BACKGROUND: Patients with mitral stenosis and atrial fibrillation (AF) require anticoagulation for stroke prevention. Thus far, all studies on direct oral anticoagulants (DOACs) have excluded patients with moderate to severe mitral stenosis. OBJECTIVES: The aim of this study was to validate the efficacy of DOACs in patients with mitral stenosis. METHODS: The study population was enrolled from the Health Insurance Review and Assessment Service (HIRA) database in the Republic of Korea, and it included patients who were diagnosed with mitral stenosis and AF and either were prescribed DOACs for off-label use or received conventional treatment with warfarin. The primary efficacy endpoint was ischemic strokes or systemic embolisms, and the safety outcome was intracranial hemorrhage. RESULTS: A total of 2,230 patients (mean age 69.7 ± 10.5 years; 682 [30.6%] males) were included in the present study. Thromboembolic events occurred at a rate of 2.22%/year in the DOAC group, and 4.19%/year in the warfarin group (adjusted hazard ratio for DOAC: 0.28; 95% confidence interval: 0.18 to 0.45). Intracranial hemorrhage occurred in 0.49% of the DOAC group and 0.93% of the warfarin group (adjusted hazard ratio for DOAC: 0.53; 95% confidence interval: 0.22 to 1.26). CONCLUSIONS: In patients with AF accompanied with mitral stenosis, DOAC use is promising and hypothesis generating in preventing thromboembolism. Our results need to be replicated in a randomized trial.

Utility of acute arrhythmia termination as an ablation endpoint for induced atrial tachyarrhythmia after complete pulmonary vein isolation during catheter ablation for persistent atrial fibrillation.

PURPOSE: The presence of inducible atrial tachyarrhythmia after pulmonary vein isolation (PVI) during radiofrequency catheter ablation (RFCA) for persistent atrial fibrillation (AF) may indicate the necessity of further substrate modification, but the optimal ablation endpoint is unknown. We sought to assess the impact of procedural termination of inducible atrial tachyarrhythmia after PVI in comparison with continued atrial tachyarrhythmia after PVI. METHODS: Among patients who underwent RFCA for persistent AF, we enrolled 93 patients who were in sinus rhythm after PVI and had inducible atrial tachyarrhythmia and 157 patients with continued atrial tachyarrhythmia after PVI. The impact of acute arrhythmia termination during further substrate modification on recurrence was compared between the two groups. RESULTS: Acute termination was achieved in 51 (54.8%) patients in the induced arrhythmia group and 61 (38.9%) in the continued arrhythmia group. During a mean 35.8 months, acute termination did not significantly reduce arrhythmia recurrence in the induced arrhythmia group (HR 0.712, 95% CI 0.400-1.266, p = 0.247), while it was associated with improved outcome in the continued arrhythmia group (HR 0.590, 95% CI 0.355-0.979, p = 0.038). Acute termination of either induced atrial tachycardia (AT) or induced AF was not associated with improved procedure outcome. Among the continued arrhythmia group, the benefit of acute termination was statistically significant in AT (HR 0.329, 95% CI 0.108-0.997, p = 0.039), but not in AF (HR 0.704, 95% CI 0.396-1.253, p = 0.233) after PVI. CONCLUSIONS: Acute termination of induced rhythm is not a reliable ablation endpoint during substrate modification in patients with inducible arrhythmia after PVI.

Relationship between airflow obstruction and coronary atherosclerosis in asymptomatic individuals: evaluation by coronary CT angiography.

Airflow obstruction is associated with increased cardiovascular morbidity and mortality. However, the causal mechanisms linking airflow obstruction with higher incidence of cardiovascular events remain elusive. We evaluated the relationship between airflow obstruction, a key feature of chronic obstructive pulmonary disease (COPD), and prevalence, extent, and severity of coronary atherosclerosis in a large cohort of asymptomatic subjects. Participants were recruited from those undergoing spirometry and coronary computed tomography angiography (CCTA) as part of a general health evaluation from March 2009 to February 2011. Subjects were required to be over 40 years of age with no known CAD. Airflow obstruction was defined as forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) < 70%. Obstructive CAD, as measured by CCTA, was defined as maximum intra-luminal stenosis ≥ 50%. Participants with airflow obstruction or normal lung function were compared in terms of obstructive CAD prevalence, the extent and severity of coronary atherosclerosis; including coronary artery calcium score (CACS), atheroma burden score (ABS), atheroma burden obstructive score (ABOS), segment involvement score (SIS), and segment stenosis score (SSS). A total of 1888 subjects were eligible for study inclusion. Compared with participants with normal lung function, those exhibiting airflow obstruction were more likely to have obstructive CAD (p = 0.002). Airflow obstruction was associated with higher CACS (p = 0.043), ABS (p = 0.002), ABOS (p = 0.017), SIS (p = 0.003), and SSS (p = 0.002). Multivariable analyses adjusted for conventional cardiovascular risk factors revealed that airflow obstruction was independently associated with presence of CAD (odds ratio 1.673, confidence intervals [CI] 1.002-2.789, p = 0.048). In this asymptomatic population, the presence of airflow obstruction was associated with a greater prevalence, extent, and severity of coronary atherosclerosis and was seen to be an independent predictor of the presence of CAD.

Underdevelopment of Left Atrial Appendage.

A patient was admitted for catheter ablation of atrial fibrillation. Cardiac computed tomography and transesophageal echocardiography revealed the absence of the left atrial appendage. However, the right atrial appendage looked normal and the level of pro B-natriuretic peptide was within normal limits. Successful catheter ablation was performed without any procedural complications and the sinus rhythm was appropriately maintained for 10 months with an antiarrhythmic drug.

Randomized Comparison of Continuous Versus Intermittent Heparin Infusion During Catheter Ablation of Atrial Fibrillation.

OBJECTIVES: This study tested the hypothesis that continuous heparin infusions would be favorable for maintaining heparin concentrations during radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF). BACKGROUND: Heparin infusions are essential for RFCA of AF. There is a paucity of data on the details for the optimal heparin infusion during RFCA of AF. METHODS: A total of 333 patients undergoing AF ablation were consecutively enrolled and randomized to intermittent or continuous heparin infusion. A heparin bolus of 100 U/kg was injected just prior to transseptal puncture. The heparin concentration necessary to maintain an optimal activated clotting time (ACT) (300 to 400 s) was determined and checked every 30 min during the procedure. The primary endpoint of the study was the frequency of the maintenance of an optimal intraprocedural ACT. RESULTS: The frequency of an optimal ACT in the continuous group was significantly higher than that in the intermittent group (64.0% vs. 57.6%, respectively, p < 0.01), whereas the total heparin level was significantly lower in the continuous group (13,162 ± 4,634 U vs. 15,837 ± 5,243 U, respectively, p < 0.01). The standard deviation of the ACT was significantly smaller in the continuous group than in the intermittent group (49 ± 30 vs. 33 ± 18, respectively, p < 0.01). Ninety-six patients had new oral anticoagulants (NOACs) before the procedure, and an optimal ACT at the first ACT check was less frequent than in patients taking warfarin (12.5% vs. 59.1%, respectively, p < 0.01). There were no significant differences in periprocedural bleeding or thromboembolic complications between the groups. CONCLUSIONS: During AF ablation, a continuous heparin infusion was superior to an intermittent heparin infusion for maintaining an optimal ACT range. (Randomized Comparison of Continuous and Intermittent Heparin Infusion During Catheter Ablation of Atrial Fibrillation [COHERE]; NCT01935557).

Achievement of successful pulmonary vein isolation: methods of adenosine testing and incremental benefit of exit block.

PURPOSE: Several approaches were tried to achieve complete pulmonary vein isolation (PVI). The aims of this study were to (1) compare adenosine-induced PV conduction and exit conduction, (2) determine the adequate adenosine dose, and (3) investigate the correlation of dormant conduction and recurrence of atrial fibrillation (AF). METHODS: A total of 378 consecutive patients who underwent PVI from June 2012 to April 2015 were prospectively included (the de novo procedure in 318 (84.1 %) and a redo procedure in 60 (15.9 %)). After the exit block was assessed, 20 mg adenosine was injected into the left atrium. If dormant conduction was observed, 12 and 6 mg of adenosine were injected sequentially. RESULTS: Exit conduction during PV pacing was observed in 34 patients (9 %), and dormant conduction was observed in 92 patients (24.3 %). Among them, 74 (80.4 %, 74/92) demonstrated dormant conduction without exit conduction and 16 (47.1 %, 16/34) showed exit conduction without dormant conduction. The 20-mg dose of adenosine had an additive yield in patients with dormant conduction, compared to that of 12 mg (93 %, 86/92) or 6 mg (80 %, 74/92). There was no significant difference in the recurrence rate regarding dormant conduction. The pattern of prevalence of reconnected origin during the redo procedure was similar to that of dormant conduction during the index procedure. CONCLUSIONS: There was a discrepancy between adenosine-induced PVI and exit block. Therefore, exit block test has additional value to verify latent incomplete PVI in conjunction with adenosine test. Furthermore, high-dose adenosine had an additive yield. CLINICAL TRIAL REGISTRATION: https://www.clinicaltrials.gov/ct2/show/NCT01932112.

Visualization of the Critical Isthmus by Tracking Delayed Potential in Edited Windows for Scar-Related Ventricular Tachycardia.

BACKGROUND AND OBJECTIVES: Identifying the critical isthmus of slow conduction is crucial for successful treatment of scar-related ventricular tachycardia. Current 3D mapping is not designed for tracking the critical isthmus and may lead to a risk of extensive ablation. We edited the algorithm to track the delayed potential in order to visualize the isthmus and compared the edited map with a conventional map. SUBJECTS AND METHODS: We marked every point that showed delayed potential with blue color. After substrate mapping, we edited to reset the annotation from true ventricular potential to delayed potential and then changed the window of interest from the conventional zone (early, 50-60%; late, 40-50% from peak of QRS) to the edited zone (early, 80-90%; late, 10-20%) for every blue point. Finally, we compared the propagation maps before and after editing. RESULTS: We analyzed five scar-related ventricular tachycardia cases. In the propagation maps, the resetting map showed the critical isthmus and entrance and exit sites of tachycardia that showed figure 8 reentry. However, conventional maps only showed the earliest ventricular activation sites and searched for focal tachycardia. All of the tachycardia cases were terminated by ablating the area around the isthmus. CONCLUSION: Identifying the channel and direction of the critical isthmus by a new editing method to track delayed potential is essential in scar-related tachycardia.

Differences between Korea and Japan in Physician Decision Making Regarding Permanent Pacemaker Implantation.

BACKGROUND AND OBJECTIVES: The number of permanent pacemakers (PPMs) implanted in patients in Japan and Korea differs significantly. We aimed to investigate the differences in decision making processes of implanting a PPM. MATERIALS AND METHODS: Our survey included 15 clinical case scenarios based on the 2008 AHA/ACC/HRS guidelines for device-based therapy of cardiac rhythm abnormalities (class unspecified). Members of the Korean and Japanese Societies of Cardiology were asked to rate each scenario according to a 5-point scale and to indicate their decisions for or against implantation. RESULTS: Eighty-nine Korean physicians and 192 Japanese physicians replied to the questionnaire. For the case scenarios in which there was a class I indication for PPM implantation, the decision to implant a PPM did not differ significantly between the two physician groups. However, the Japanese physicians were significantly more likely than the Korean physicians to choose implantation in class IIa scenarios (48% vs. 37%, p<0.001), class IIb scenarios (40% vs. 19%, p<0.001), and class III scenarios (36% vs. 18%, p<0.001). These results did not change when the cases were categorized based on disease entity, such as sinus node dysfunction and conduction abnormality. CONCLUSION: Korean physicians are less likely than Japanese physicians to favor a PPM implantation when considering a variety of clinical case scenarios, which probably contributes to the relatively small number of PPMs implanted in patients in Korea as compared with those in Japan.

Long-term outcomes of remote magnetic navigation for ablation of supraventricular tachycardias.

BACKGROUND: Little is known about the long-term outcomes of catheter ablation of supraventricular tachycardia (SVT) using remote magnetic navigation system (RMN). METHODS: One hundred twenty patients underwent catheter ablation of SVTs with RMN (Niobe, Stereotaxis, USA): atrioventricular nodal re-entrant tachycardia (AVNRT; n = 59), atrioventricular re-entrant tachycardia (AVRT; n = 45), and focal atrial tachycardia (AT, n = 16). The outcome of AVRT with right free wall accessory pathway was compared with those of a group of 26 consecutive patients undergoing manual ablation. RESULTS: Mean follow-up period was 2.2 ± 1.4 years. Overall arrhythmia-free survival was 86%; AVRT (77%), AVNRT (96%), and focal AT (71%). After the learning period (initial 50 cases), procedural outcomes had improved for AVRT and AVNRT (91% in overall group, 90% in AVRT group, 100% in AVNRT group, and 68% in focal AT group). The recurrence-free rate was higher for the free wall accessory pathways than those of the other sites (92 vs. 73%, log-rank P = 0.06). Furthermore, when it is confined for the right free wall accessory pathway, RMN showed excellent long-term outcome (7/7, 100 %) compared to the results of manual approach (18/26, 69.2%, log-rank P = 0.07). CONCLUSIONS: RMN showed favorable long-term outcomes for the ablation of SVT. In our experience, RMN-guided ablation may be associated with a higher success rate as compared to manual ablation when treating right-sided free wall pathways.

Benefit of implantable cardioverter-defibrillator therapy after generator replacement in patients with Brugada syndrome.

BACKGROUND: An implantable cardioverter-defibrillator (ICD) is the only proven effective therapeutic strategy for patients with Brugada syndrome (BS). However, it is controversial whether the device should be replaced even in patients who had never experienced appropriate ICD therapy until the time of generator replacement. METHODS AND RESULTS: This was a nationwide, multicenter retrospective study that enrolled patients who were diagnosed with BS and had an ICD implantation between January 1998 and April 2014. Appropriate ICD therapies administered for ventricular tachyarrhythmia were evaluated during follow-up. A total of 117 patients (age 43 ± 12 years, male 115 [98.3%]) were enrolled, and the mean follow-up duration was 6.0 ± 4.1 years. Thirty-seven (31.6%) patients had experienced appropriate ICD therapy during follow-up. Of all patients, 46 underwent replacement of the device. After the first generator replacement, the incidence of appropriate ICD therapy remained as high as 65.2% in patients who previously experienced appropriate ICD therapy before generator replacement. In 30 patients who did not experience any cardiac events until the first generator change, two (8.7%) had an episode of appropriate ICD therapy afterwards. CONCLUSIONS: No episode of ICD therapy before generator replacement could not guarantee a safe clinical course. ICD generator replacement should be considered even in patients without ICD therapy before.

Paced QRS axis as a predictor of pacing-induced left ventricular dysfunction.

PURPOSE: The selection of the optimal right ventricular (RV) pacing site remains unclear. We hypothesized that a normal paced QRS axis would provide a physiological ventricular activation and lead to a better long-term outcome. METHODS: We evaluated 187 patients who underwent a permanent pacemaker implantation and were dependent on RV pacing. The pacing sites were classified as the apex and non-apex according to the chest radiography. A paced QRS axis was defined as that between -30° and 90°. Preservation of the left ventricular (LV) systolic function was defined as that with a <10 % decrease in the ejection fraction after the pacemaker implantation. RESULTS: The median follow-up period was 5.8 years (interquartile 3.9-9.0). Radiographically, the RV leads were located in the apex (n = 148, 79 %) or non-apex (n = 39, 21 %). In the electrocardiogram, normal paced and abnormal paced QRS axes were observed in 28 patients (15 %) and 159 patients (85 %), respectively. The LV ejection fraction was decreased in the patients with an abnormal paced QRS axis (-10 ± 10 %, P < 0.001), but not in those with a normal axis (0 ± 6 %, P = 0.80). The electrocardiographic determinant differentiated a preserved LV function (95 % vs. 35 %, log-rank P = 0.04). Among the patients with radiographically non-apical pacing, a normal paced QRS axis was an additional meaningful predictor of a preserved LV function after the pacemaker implantation (95 % vs. 24 %, log-rank P = 0.002). CONCLUSION: Compared with the radiographic method, a normal paced QRS axis was associated with a preserved LV function.

Influence of nationwide policy on citizens' awareness and willingness to perform bystander cardiopulmonary resuscitation.

AIMS: Public awareness to cardiopulmonary resuscitation (CPR) and cardiac arrest is influenced by systemic factors including related policies and legislations in the community. Here, we describe and compare the results of the two nationwide CPR surveys in 2007 and 2011 examining public awareness and attitudes to bystander CPR in South Korea along with changes in nationwide CPR policies and systemic factors. METHODS: This population-based study used specially designed questionnaires via telephone surveys. We conducted bi-temporal surveys by stratified cluster sampling to assess the impact of age, gender, and geographic regions in 2007 (n=1029) and in 2011 (n=1000). Logistic regression analysis was performed to identify factors associated with willingness to perform bystander CPR. RESULTS: Public awareness of automated external defibrillators increased from 3.0% in 2007 to 32.6% in 2011. The proportion of the population that underwent CPR training within the previous 2 years increased significantly from 26.9% to 49.0%. The factors most related with intention of bystander CPR were male gender, younger age, CPR awareness, recent CPR training, and qualified CPR learning. In 2011, 75.8% of respondents were more willing to perform bystander CPR for stranger vs. 68.3% in 2007 (p=0.002). Additional dispatcher hands-only CPR increased this proportion (85.8%, p<0.001). However, bystander CPR experience rates remained unchanged (3.6-3.9%). CONCLUSION: Changes in nationwide CPR policies and systemic factors affected citizens' awareness and willingness to perform bystander CPR. Additionally, applied dispatcher hands-only CPR and publicity increased public willingness to perform bystander CPR.