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Background The cornerstone of the treatment of vasovagal syncope (VVS) is lifestyle modifications; however, some patients incur life-disturbing attacks despite compliance with these treatments which underscores the importance of pharmacological interventions. Methods In this open-label multi-center randomized controlled trial, we are going to randomize 1375 patients with VVS who had ≥2 syncopal episodes in the last year into three parallel arms with a 2:2:1 ratio to receive midodrine, fludrocortisone, or no medication. All patients will be recommended to drink 2 to 3 liters of fluids per day, consume 10 grams of NaCl per day, and practice counter-pressure maneuvers. In medication arms, patients will start on 5 mg of midodrine TDS or 0.05 mg of fludrocortisone BD. After one week the dosage will be up-titrated to midodrine 30 mg/day and fludrocortisone 0.2 mg/day. Patient tolerance will be the principal guide to dosage adjustments. We will follow-up the patients on 3, 6, 9, and 12 months after randomization. The primary outcome is the time to first syncopal episode. Secondary outcomes include the recurrence rate of VVS, time interval between first and second episodes, changes in quality of life (QoL), and major and minor adverse drug reactions. QoL will be examined by the 36-Item Short Form Survey questionnaire at enrollment and 12 months after randomization. Conclusion The COMFORTS trial is the first study that aims to make a head-to-head comparison between midodrine and fludrocortisone, against a background of lifestyle modifications for preventing recurrences of VVS and improving QoL in patients with VVS.

BACKGROUND: Mutations in SCN5A are rarely found in Thai patients with Brugada syndrome (BrS). Recent evidence suggested that common genetic variations may underlie BrS in a complex inheritance model. OBJECTIVE: The purpose of this study was to find common and rare/low-frequency genetic variants predisposing to BrS in persons in Thailand. METHODS: We conducted a genome-wide association study (GWAS) to explore the association of common variants in 154 Thai BrS cases and 432 controls. We sequenced SCN5A in 131 cases and 205 controls. Variants were classified according to current guidelines, and case-control association testing was performed for rare and low-frequency variants. RESULTS: Two loci were significantly associated with BrS. The first was near SCN5A/SCN10A (lead marker rs10428132; odds ratio [OR] 2.4; P = 3 × 10-10). Conditional analysis identified a novel independent signal in the same locus (rs6767797; OR 2.3; P = 2.7 × 10-10). The second locus was near HEY2 (lead marker rs3734634; OR 2.5; P = 7 × 10-9). Rare (minor allele frequency [MAF] 0.0001) variants also was observed in cases, with 1 variant (SCN5A: p.Arg965Cys) detected in 4.6% of Thai BrS patients vs 0.5% in controls (P = 0.015; OR 9.8; 95% CI 1.2-82.3). CONCLUSION: The genetic basis of BrS in Thailand includes a wide spectrum of variant frequencies and effect sizes. As previously shown in European and Japanese populations, common variants near SCN5A and HEY2 are associated with BrS in the Thai population, confirming the transethnic transferability of these 2 major BrS loci.

Transvenous Lead Extraction (TLE) is a standard treatment for some late Cardiac Implantable Electronics Device (CIED) complications. The outcome of transvenous lead extraction procedure in Thailand is not robust.A Single-center retrospective cohort of TLE procedures performed at Ramathibodi hospital between January 2008 and December 2020 was studied.There were 157 leads from 105 patients who underwent lead removal procedure during the specified period. Data analysis was performed from 79 TLE patients due to incomplete data and lead explant procedure of the excluded subjects. Mean patients' age was 57.7 ± 18.7 years, with 70.9% male. There were 82 pacemaker leads, 35 ICD leads, and 5 CS leads (mean number of leads were 1.54 ± 0.66 per patient), with mean implanted duration of 87.8 ± 68.2 months. Main indication for TLE was infection-related, which accounted for 67.1% of the cases. Overall clinical success rate was 97.5%. Mean operative time was 163.8 ± 69.5 min. Major complications occurred in 4 patients (5.1%) with one in-hospital mortality from severe sepsis.TLE using laser sheath and rotating mechanical sheath for transvenous lead extraction is effective and safe, even outside high-volume center.

We aim to provide a critical appraisal of basic concepts underlying signal recording and processing technologies applied for (i) atrial fibrillation (AF) mapping to unravel AF mechanisms and/or identifying target sites for AF therapy and (ii) AF detection, to optimize usage of technologies, stimulate research aimed at closing knowledge gaps, and developing ideal AF recording and processing technologies. Recording and processing techniques for assessment of electrical activity during AF essential for diagnosis and guiding ablative therapy including body surface electrocardiograms (ECG) and endo- or epicardial electrograms (EGM) are evaluated. Discussion of (i) differences in uni-, bi-, and multi-polar (omnipolar/Laplacian) recording modes, (ii) impact of recording technologies on EGM morphology, (iii) global or local mapping using various types of EGM involving signal processing techniques including isochronal-, voltage- fractionation-, dipole density-, and rotor mapping, enabling derivation of parameters like atrial rate, entropy, conduction velocity/direction, (iv) value of epicardial and optical mapping, (v) AF detection by cardiac implantable electronic devices containing various detection algorithms applicable to stored EGMs, (vi) contribution of machine learning (ML) to further improvement of signals processing technologies. Recording and processing of EGM (or ECG) are the cornerstones of (body surface) mapping of AF. Currently available AF recording and processing technologies are mainly restricted to specific applications or have technological limitations. Improvements in AF mapping by obtaining highest fidelity source signals (e.g. catheter–electrode combinations) for signal processing (e.g. filtering, digitization, and noise elimination) is of utmost importance. Novel acquisition instruments (multi-polar catheters combined with improved physical modelling and ML techniques) will enable enhanced and automated interpretation of EGM recordings in the near future.

BACKGROUND: Guideline-recommended doses of angiotensin-converting-enzyme (ACE) inhibitors or angiotensin-receptor blockers (ARBs), and β blockers are similar for men and women with heart failure with reduced ejection fraction (HFrEF), even though there are known sex differences in pharmacokinetics of these drugs. We hypothesised that there might be sex differences in the optimal dose of ACE inhibitors or ARBs and β blockers in patients with HFrEF.METHODS: We did a post-hoc analysis of BIOSTAT-CHF, a prospective study in 11 European countries of patients with heart failure in whom initiation and up-titration of ACE inhibitors or ARBs and β blockers was encouraged by protocol. We included only patients with left ventricular ejection fraction less than 40%, and excluded those who died within the first 3 months. Primary outcome was a composite of time to all-cause mortality or hospitalisation for heart failure. Findings were validated in ASIAN-HF, an independent cohort of 3539 men and 961 women with HFrEF.FINDINGS: Among 1308 men and 402 women with HFrEF from BIOSTAT-CHF, women were older (74 [12] years vs 70 [12] years, pINTERPRETATION: This study suggests that women with HFrEF might need lower doses of ACE inhibitors or ARBs and β blockers than men, and brings into question what the true optimal medical therapy is for women versus men.FUNDING: European Commission.

Aims To examine sex differences in clinical characteristics, echocardiographic features, quality of life and 1-year death or heart failure (HF) hospitalization outcomes in patients with/without diabetes mellitus (DM).Methods and results Utilizing the Asian Sudden Cardiac Death in HF (ASIAN-HF) registry, 5255 patients (mean age 59.6 +/- 13.1, 78% men) with symptomatic HF with reduced ejection fraction (HFrEF) were stratified by DM status to address the research aims. Despite similar prevalence of DM between Asian men (43%) and women (42%), the odds of DM increased at lower body mass index in women vs. men (>= 23 vs. >= 27.5 kg/m(2), P-interaction = 0.014). DM was more strongly related to chronic kidney disease in women vs. men [adjusted odds ratio (OR) 1.85, 95% confidence interval (CI) 1.33-2.57 vs. OR 1.32, 95% CI 1.11-1.56, P-interaction = 0.009]. Sex also modified the relationship between DM and left ventricular geometry (P-interaction = 0.003), whereby DM was associated with amore concentric left ventricular geometry in women than men. Women had lower quality of life than men (P Conclusions Asian women with HFrEF were more likely to have DM despite a lean body mass index, a greater burden of chronic kidney disease and more concentric left ventricular geometry, compared to men. Furthermore, DM confers worse quality of life, irrespective of sex, and a greater risk of adverse outcomes in women than men. These data underscore the need for sex-specific approaches to diabetes in patients with HF.

Brugada syndrome (BrS) is an inherited ion channel channelopathy predisposing to ventricular arrhythmias and sudden cardiac death. Originally believed to be predominantly associated with mutations in SCN5A encoding for the cardiac sodium channel, mutations of 18 genes other than SCN5A have been implicated in the pathogenesis of BrS to date. Diagnosis is based on the presence of a spontaneous or drug-induced coved-type ST segment elevation. The predominant electrophysiological mechanism underlying BrS remains disputed, commonly revolving around the three main hypotheses based on abnormal repolarization, depolarization or current-load match. Evidence from computational modelling, pre-clinical and clinical studies illustrates that molecular abnormalities found in BrS lead to alterations in excitation wavelength (λ), which ultimately elevates arrhythmic risk. A major challenge for clinicians in managing this condition is the difficulty in predicting the subset of patients who will suffer from life-threatening ventricular arrhythmic events. Several repolarization risk markers have been used thus far, but these neglect the contributions of conduction abnormalities in the form of slowing and dispersion. Indices incorporating both repolarization and conduction based on the concept of λ have recently been proposed. These may have better predictive values than the existing markers. Current treatment options include pharmacological therapy to reduce the occurrence of arrhythmic events or to abort these episodes, and interventions such as implantable cardioverter-defibrillator insertion or radiofrequency ablation of abnormal arrhythmic substrate. Keywords: Brugada syndrome, Ion channel, Repolarization, Depolarization, Risk stratification

Background Utilization of cardiac Magnetic Resonance Imaging (cMRI) as an imaging modality in clinical practice is rapidly increasing. More evidence from randomized studies establishing clinical safety and performance of pacing systems in patients undergoing a cMRI scan is needed. Objectives The purpose of this prospective, multi-center, randomized study was to demonstrate safety and efficacy of the Accent MRI conditional pacing systems in patients undergoing cMRI scan. Methods Patients (n = 283) indicated for dual-chamber pacemaker implant were randomized to either the MRI Group (MG) (n = 140) or the Control Group (CG) (n = 143) after successful device implantation of the Accent MRI system. Clinical evaluation and device interrogation were performed at pre- and post-MRI scan, and one month post-MRI for all patients. At 9–12 weeks post-implant, patients in MG underwent a non-diagnostic cMRI scan at 1.5 Tesla (T) while patients in CG underwent device interrogation and clinical evaluation twice with a 45-minute waiting period in between. The safety endpoint was freedom from MRI scan-related complications and that for efficacy was significant changes in right atrial/ventricular (RA/RV) capture threshold and sensing amplitude between right before MRI, immediately after MRI and one month post-MRI. Results Results showed 100% freedom from MRI scan related complications. There were no significant changes in device performance between pre-MRI scan and one month post MRI scan time points in both study groups. Conclusions cMRI scanning with 1.5 T scanners is safe in patients implanted with the Accent MRI conditional pacing system and has no significant effect on the electrical parameters of the device and leads. This article is protected by copyright. All rights reserved

Background Brugada syndrome (BrS) is defined as presenting of type-1 Brugada pattern (BrP). BrS can also be induced by fever. This study demonstrated a highest prevalence of fever-induced BrS ever reported. Method During May 2014, febrile (oral temperature ≥ 38 °C) and nonfebrile patients underwent standard and high leads (V1 and V2 at 2nd intercostal space) electrocardiogram. Risk factor and cardiac symptoms were recorded. Patients with a persistent of type-1 BrP after fever had subsided were excluded. The prevalence of BrS, type-2 BrP and early repolarization pattern (ERP) were demonstrated. Results A total of 401 patients, 152 febrile, and 249 nonfebrile, were evaluated. BrS was identified in six febrile patients (five males and one female) and two males in nonfebrile patients. The study demonstrated higher prevalence of BrS in febrile group compared to nonfebrile group (4.0% vs 0.8%, respectively, P = 0.037). Among fever-induced BrS patients, three patients (50.0%) experienced cardiac symptoms before and at the time of presentation and two patients (33.3%) had history of first-degree relative sudden death. No ventricular arrhythmia was observed. All of type-1 BrP disappeared after fever had subsided. We found no difference in prevalence of type-2 BrP in febrile and nonfebrile group (2.0% vs 2.8%, respectively, P > 0.05) as well as ERP (3.3% vs 6.4%, respectively, P > 0.05). Conclusions Our study showed a highest prevalence of fever induced BrS ever reported. A larger study of prevalence, risk stratification, genetic test and management of fever-induced BrS should be done, especially in an endemic area.

Heart failure with preserved ejection fraction (HFpEF) is a global public health problem. Unfortunately, little is known about HFpEF across Asia.We prospectively studied clinical characteristics, echocardiographic parameters and outcomes in 1204 patients with HFpEF (left ventricular ejection fraction ≥50%) from 11 Asian regions, grouped as Northeast Asia (Hong Kong, Taiwan, China, Japan, Korea, n = 543), South Asia (India, n = 252), and Southeast Asia (Malaysia, Thailand, Singapore, Indonesia, Philippines, n = 409). Mean age was 68 ±12 years (37% were 65 years) and 50% were women. Seventy per cent of patients had ≥2 co-morbidities, most commonly hypertension (71%), followed by anaemia (57%), chronic kidney disease (50%), diabetes (45%), coronary artery disease (29%), atrial fibrillation (29%) and obesity (26%). Southeast Asian patients had the highest prevalence of all co-morbidities except atrial fibrillation, South Asians had the lowest prevalence of all co-morbidities except anaemia and obesity, and Northeast Asians had more atrial fibrillation. Left ventricular hypertrophy and concentric remodelling were most prominent among Southeast and South Asians, respectively (P 0.001). Overall, 12.1% of patients died or were hospitalized for heart failure within 1 year. Southeast Asians were at higher risk for adverse outcomes, independent of co-morbidity burden and cardiac geometry.These first prospective multinational data from Asia show that HFpEF affects relatively young patients with a high burden of co-morbidities. Regional differences in types of co-morbidities, cardiac remodelling and outcomes of HFpEF across Asia have important implications for public health measures and global HFpEF trial design.

Background— Implantable cardioverter defibrillators (ICDs) are lifesaving devices for patients with heart failure (HF) and reduced ejection fraction. However, utilization and determinants of ICD insertion in Asia are poorly defined. We determined the utilization, associations of ICD uptake, patient-perceived barriers to device therapy and, impact of ICDs on mortality in Asian patients with HF. Methods and Results— Using the prospective ASIAN-HF (Asian Sudden Cardiac Death in Heart Failure) registry, 5276 patients with symptomatic HF and reduced ejection fraction (HFrEF) from 11 Asian regions and across 3 income regions (high: Hong Kong, Japan, Korea, Singapore, and Taiwan; middle: China, Malaysia, and Thailand; and low: India, Indonesia, and Philippines) were studied. ICD utilization, clinical characteristics, as well as device perception and knowledge, were assessed at baseline among ICD-eligible patients (EF ≤35% and New York Heart Association Class II-III). Patients were followed for the primary outcome of all-cause mortality. Among 3240 ICD-eligible patients (mean age 58.9±12.9 years, 79.1% men), 389 (12%) were ICD recipients. Utilization varied across Asia (from 1.5% in Indonesia to 52.5% in Japan) with a trend toward greater uptake in regions with government reimbursement for ICDs and lower out-of-pocket healthcare expenditure. ICD (versus non-ICD) recipients were more likely to be older (63±11 versus 58±13 year; P P P Conclusions— ICDs reduce mortality risk, yet utilization in Asia is low; with disparity across geographic regions and socioeconomic status. Better patient education and targeted healthcare reforms in extending ICD reimbursement may improve access. Clinical Trial Registration— URL: https://clinicaltrials.gov/ct2/show/NCT01633398 . Unique identifier: NCT01633398.

Aims Our aim is to determine mortality and morbidity in Asian patients under clinical management for heart failure (HF). Specifically, we will define the incidence of, and risk factors for, sudden cardiac death, as well as the socio-cultural factors influencing therapeutic choices in these patients. Methods This is a prospective observational multinational Asian registry of 5000 patients with symptomatic HF (stage C) and LV systolic dysfunction (EF ≤ 40%) involving 44 centres across 11 Asian regions (China, Hong Kong, India, Indonesia, Japan, Korea, Malaysia, Philippines, Singapore, Taiwan and Thailand). Data collection includes demographic variables, clinical symptoms, functional status, date of HF diagnosis and prior cardiovascular investigations, clinical risk factors, lifestyle factors, socio-economic status, and survey of cultural beliefs, health practices, and attitudes towards device therapy. Centre-level characteristics (case load, referral pattern, specialization, and infrastructure) are also obtained. Patients uniformly undergo standard 12-lead ECG and transthoracic echocardiography at baseline, and are followed over 3 years for outcomes of death or hospitalization. The mode of death and cause of hospitalization are adjudicated by a central event adjudication committee using pre-specified criteria. Perspective By providing prospective data regarding the demographics, risk factors, and outcomes of Asian patients under treatment for HF, the ASIAN-HF registry is expected to advance fundamental understanding of the burden and predictors of death and hospitalization among these patients. The knowledge gained will be important for guiding resource allocation and planning preventive strategies to address the unmet and growing clinical needs of patients with cardiovascular disease in Asia. Trial registration NCT01633398

Aims To characterize regional and ethnic differences in heart failure (HF) across Asia. Methods and results We prospectively studied 5276 patients with stable HF and reduced ejection fraction (≤40%) from 11 Asian regions (China, Hong Kong, India, Indonesia, Japan, Korea, Malaysia, Philippines, Singapore, Taiwan, and Thailand). Mean age was 59.6 ± 13.1 years, 78.2% were men, and mean body mass index was 24.9 ± 5.1 kg/m2. Majority (64%) of patients had two or more comorbid conditions such as hypertension (51.9%), coronary artery disease (CAD, 50.2%), or diabetes (40.4%). The prevalence of CAD was highest in Southeast Asians (58.8 vs. 38.2% in Northeast Asians). Compared with Chinese ethnicity, Malays (adjusted odds ratio [OR] 1.97, 95% CI 1.63–2.38) and Indians (OR 1.44, 95% CI 1.24–1.68) had higher odds of CAD, whereas Koreans (OR 0.38, 95% CI 0.29–0.50) and Japanese (OR 0.44, 95% CI 0.36–0.55) had lower odds. The prevalence of hypertension and diabetes was highest in Southeast Asians (64.2 and 49.3%, respectively) and high-income regions (59.7 and 46.2%, respectively). There was significant interaction between ethnicity and region, where the adjusted odds were 3.95 (95% CI 2.51–6.21) for hypertension and 4.91 (95% CI 3.07–7.87) for diabetes among Indians from high- vs. low-income regions; and 2.60 (95% CI 1.66–4.06) for hypertension and 2.62 (95% CI 1.73–3.97) for diabetes among Malays from high- vs. low-income regions. Conclusions These first prospective multi-national data from Asia highlight the significant heterogeneity among Asian patients with stable HF, and the important influence of both ethnicity and regional income level on patient characteristics. ClinicalTrials.gov identifier NCT01633398.

The Septal Pacing for Atrial Fibrillation Suppression Evaluation (SAFE) study is a single-blinded, parallel randomized designed multicenter study in pacemaker indicated patients with paroxysmal atrial fibrillation (AF). The objective is to evaluate whether the site of atrial pacing--conventional right atrial appendage versus low atrial septal--with or without atrial overdrive pacing will influence the development of persistent AF. The study will provide a definitive answer to whether a different atrial pacing site or the use of AF suppression pacing or both can give incremental antiarrhythmic benefit when one is implanting a device for a patient with a history of paroxysmal AF.

ObjectivesThe purpose of this study was to determine the long-term clinical outcomes of catheter ablation of atrial fibrillation (AF) substrate for high-risk patients with AF.BackgroundThe benefits of catheter ablation for high-risk AF patients with respect to mortality and stroke reductions remain unclear.MethodsWe performed AF substrate ablation guided by complex fractionated atrial electrogram (CFAE) mapping in 674 high-risk AF patients. The clinical end points were sinus rhythm (SR), death, stroke, or bleeding. Of these 674 patients, 635 were available for follow-up and made up the study cohort. The patients were relatively old (mean age 67 ± 12 years) and 129 had an ejection fraction (EF)

Introduction: Sudden unexpected death (SUD) is the leading cause of death worldwide. Although coronary atherosclerosis is a major cause of SUD, standard autopsy may not explain the cause of SUD. The frequency of unidentified cause of death in Thailand is not known. Therefore, we conduct a retrospective study to address the frequency of unidentified cause of death in SUD of Thailand. Hypothesis: The frequency of unidentified cause of death in SUD of Thailand could be higher than Caucasian. Methods: We reviewed autopsy reports of SUD in Ramathibodi Hospital, Mahidol University, Thailand, during January 2012-December 2013. The autopsy reports were excluded if; (1) the age was over 65 or under 18 years; (2) the death was expected death: e.g. the decease was in hospice care; (3) the cause was an obvious non-cardiac cause: e.g. trauma, overdose, or pneumonia; (4) the decease was not Thai citizen. Results: A total of 116 cases, 108 males (93.1%) and 8 female (6.9%), were included. The mean age was 49.7±15.2 years. The cause of death was identified as ischemic heart disease in 74 cases (63.8%), which 32 cases (27.6%) were significant coronary atherosclerosis without infarction, 23 cases (19.8%) were acute myocardial infarction, and 19 cases (16.4%) were old myocardial scaring. The causes of death were due to myocardial bridging in 8 cases (6.9%), isolated left ventricular hypertrophy in 6 cases (5.2%), hypertrophic cardiomyopathy in 3 cases (2.6%), and myocarditis in 2 cases (1.7%). Other causes were 1 case (0.9%) of obesity cardiomyopathy, 1 case (0.9%) of aortic stenosis, and 1 case (0.9%) of dilated cardiomyopathy. Interestingly, the cause of death was not clearly identified in 20 cases (17.2%) from standard autopsy, including 5 cases (4.3%) without any co-morbidity, 6 cases (5.2%) with non-significant atherosclerosis, 4 cases (3.4%) with non-toxic level of prescribed drugs, 3 cases (2.6%) with non-toxic level of alcohol, and 2 cases (1.7%) with history of epilepsy. Conclusions: We demonstrated higher frequency of unidentified cause of death in Thai SUD compared to Caucasian, as well as frequency of myocardial bridging. However, the frequency of ischemic heart disease was lower. Further incidence study and molecular autopsy of SUD should be conducted in Asian population.

OBJECTIVES We sought to test the hypothesis that complex fractionated electrograms (CFAEs) recorded during atrial fibrillation (AF) could be used as target sites for catheter ablation of AF. BACKGROUND Mapping of AF in humans has shown that areas of CFAEs correlate with areas of slowed conduction and pivot points of reentrant wavelets. We hypothesized that such areas of CFAEs could be identified in patients with AF and might serve as target sites for catheter ablation to maintain sinus rhythm. METHODS The study population included 121 patients (29 females; mean age, 63 years) with refractory AF (57 paroxysmal, 64 chronic). All patients underwent nonfluoroscopic electroanatomic mapping (CARTO) during AF. Using CARTO, the biatrial replica, displayed in a three-dimensional color-coded voltage map, was created during AF, and areas associated with CFAEs were identified. Radiofrequency ablation of the area with CFAEs was performed, aiming to eliminate CFAE and/or convert to sinus rhythm. RESULTS Complex fractionated atrial electrograms were found in seven of nine regions of both atria, but were mainly confined to the interatrial septum, pulmonary veins, roof of left atrium, and left posteroseptal mitral annulus and coronary sinus ostium. Ablations of the areas associated with CFAEs resulted in termination of AF without external cardioversion in 115 of the 121 patients (95%); 32 (28%) required concomitant ibutilide treatment. At the one-year follow-up, 110 (91%) patients were free of arrhythmia and symptoms, 92 after one ablation and 18 after two. CONCLUSIONS Areas with CFAEs represent a defined electrophysiologic substrate and are ideal target sites for ablations to eliminate AF and maintain normal sinus rhythm.

The overall efficacy of transthoracic biphasic shocks delivered for conversion of atrial fibrillation (AF) has been demonstrated. We compared 2 different energy waveforms, either the biphasic rectilinear (BRL) waveform or the biphasic truncated exponential (BTE) waveform, in the conversion of AF to sinus rhythm. The relation between energy required for the conversion of AF, the type of biphasic waveform, and patient characteristics were examined. Serum levels of cardiac troponin I were measured before and after cardioversion, as well as postprocedural skin erythema and discomfort. In this prospective trial, 101 patients (mean age 61 +/- 15 years, 72 men [71%]) referred for elective electrical cardioversion of AF were randomized to either a BTE or a BRL device. Shocks were delivered in a step-up fashion beginning with 50 J (then 100 J, 200 J, repeat 200 J, and then crossover to 360 J). One hundred patients were successfully converted to sinus rhythm (99% success rate). There was no difference in efficacy at any energy level used, regardless of the duration of the arrhythmia. In addition, there was no difference in cumulative success. Troponin I did not significantly increase after cardioversion, regardless of the total energy used. A positive correlation between skin erythema and skin discomfort after shock (24 to 48 hours) was seen with increasing cumulative energies. There was also a positive trend toward increasing energy requirements as chest circumference and body mass index increased. Thus, biphasic waveforms are safe and effective at converting AF to sinus rhythm. In this study population, there was no clinical difference between the BRL and the BTE waveforms.

Background: Brugada syndrome (BrS) is reported to be an important etiology of sudden cardiac death in Asian population. Prevalence of BrS has been reported in various regions, countries, and ethnicities. Our study is the first systematic review and meta-analysis assessing worldwide prevalence of BrS

To the Editor: A preoperative ECG of a febrile (38.0 C) 56-year-old Thai man diagnosed with acute appendicitis revealed type1 Brugada pattern (BrP) (Fig. 1a). His ECG was repeated at 15 and 30 min, which showed type-2 BrP (Fig. 1b). The patient denied clinical manifestations or family history of Brugada syndrome (BrS). He was diagnosed with asymptomatic BrS. Many asymptomatic BrS unmasked by fever have been reported. Moreover, fever has also triggered ventricular arrhythmias [1]. Electrophysiological study or drug challenge test should be done to stratify the risk of arrhythmias in asymptomatic BrS [2]. However, it is not suitable to perform such a test before emergency operation. Therefore, to avoid exacerbation of ventricular arrhythmias, class IC/ IA antiarrhythmic drugs, epidural bupivacaine, acetylcholine, propranolol, propofol, pinacidil, and nicorandil should not be used [3]. In our case, by using general anesthesia, intravenous etomidate was used for induction and seroflurane was used for maintenance. Rocuronium was used as a muscle relaxant. ECG was monitored and external defibrillator was installed for the entire operation. The patient uneventfully went to an appendectomy. His ECG was normal during non-febrile state (Fig. 1c).

Background In addition to lowering cholesterol, statins stabilise atherosclerotic plaques and can potentially reduce the incidence of ventricular arrhythmias. We tested the hypothesis that prior statin therapy is associated with a lower incidence of inhospital ventricular arrhythmias among patients with acute coronary syndrome (ACS). Methods The study population consisted of 2007 patients (mean age 64 years, 67.5% male) enrolled in the Thai Registry of Acute Coronary Syndrome, a prospective, multicentre, nationwide, observational study of patients with ACS. Patients were categorised as either statin users or non-users according to their reports of statin use before enrolment at their initial presentation. The primary endpoint was inhospital ventricular arrhythmias. The secondary endpoint was a composite endpoint of inhospital ventricular arrhythmias or inhospital cardiac death. A propensity-adjusted multivariate model was developed to assess the effects of statin use on the primary and secondary endpoints. Results During a mean hospital stay of 7 days, a total of 96 patients (4.8%) died; 82 (4.1%) of the deaths were due to cardiac causes. The primary and secondary endpoints were reached in 163 patients (8.1%) and 194 patients (9.7%), respectively. A total of 525 patients (26.2%) had used statins prior to hospitalisation. After adjusting for the propensity scores and other relevant covariates, statin use was associated with lower risks of the primary (adjusted OR 0.505, 95% CI 0.276 to 0.923) and secondary endpoints (adjusted OR 0.498, 95% CI 0.276 to 0.897). Conclusions The use of statins is associated with a reduced incidence of ventricular arrhythmias among patients with ACS.

Intracranial hemorrhage (ICH) is one of the most common non-cardiac causes of sudden unexpected death (SUD). In western population, subarachnoid hemorrhage (SAH) is the most common etiology (51.3%) of ICH followed by hypertensive intracerebral hemorrhage (HICH) (18.8%). However, the frequency of SAH

HEALY, E., ET AL.: A Case of Bad Timing: Inappropriate Implantable Cardioverter Defibrillator Therapy Due to a Critically Placed Premature Ventricular Contraction. A 58-year-old man with an ischemic cardiomyopathy underwent ICD implantation after having an electrophysiological study positive for inducible, sustained monomorphic VT. Approximately 1 week later he experienced a shock. Inspection of stored electrograms revealed that a run of nonsustained VT had initiated his ICD to charge. The episode spontaneously terminated, yet the shock was still delivered during sinus rhythm. Further inspection revealed that a critically timed PVC during the "second look" interval resulted in delivered therapy. Thus, inappropriate ICD therapy can result from causes other than SVT, lead malfunction, or over sensing.

Background— The underlying electrophysiological mechanism that causes an abnormal ECG pattern and ventricular tachycardia/ventricular fibrillation (V t /VF) in patients with the Brugada syndrome (BrS) remains unelucidated. However, several studies have indicated that the right ventricular outflow tract (RVOT) is likely to be the site of electrophysiological substrate. We hypothesized that in patients with BrS who have frequent recurrent VF episodes, the substrate site is the RVOT, either over the epicardium or endocardium; abnormal electrograms would be identified at this location, which would serve as the target site for catheter ablation. Methods and Results— We studied 9 symptomatic patients with the BrS (all men; median age 38 years) who had recurrent VF episodes (median 4 episodes) per month, necessitating implantable cardioverter defibrillator discharge. Electroanatomic mapping of the right ventricle, both endocardially and epicardially, and epicardial mapping of the left ventricle were performed in all patients during sinus rhythm. All patients had typical type 1 Brugada ECG pattern and inducible V t /VF; they were found to have unique abnormal low voltage (0.94±0.79 mV), prolonged duration (132±48 ms), and fractionated late potentials (96±47 ms beyond QRS complex) clustering exclusively in the anterior aspect of the RVOT epicardium. Ablation at these sites rendered V t /VF noninducible (7 of 9 patients [78%]; 95% confidence interval, 0.40 to 0.97, P =0.015) and normalization of the Brugada ECG pattern in 89% (95% confidence interval, 0.52 to 0.99; P =0.008). Long-term outcomes (20±6 months) were excellent, with no recurrent V t /VF in all patients off medication (except 1 patient on amiodarone). Conclusions— The underlying electrophysiological mechanism in patients with BrS is delayed depolarization over the anterior aspect of the RVOT epicardium. Catheter ablation over this abnormal area results in normalization of the Brugada ECG pattern and prevents V t /VF, both during electrophysiological studies as well as spontaneous recurrent V t /VF episodes in patients with BrS.

Radiofrequency catheter ablation (RFCA) is widely accepted as a curative treatment for many types of cardiac arrhythmias.The authors retrospectively reviewed 1,193 cases (mean age 45, 41% male) performed in the electrophysiology laboratory at Ramathibodi Hospital from 1996 to 2007. Success rate, recurrence rate and complications were analyzed.Ablations of atrioventricular nodal reentrant tachycardia (AVNRT, 428 cases, 35.9%) and atrioventricular reentrant tachycardia (AVRT, 346 cases, 29%) were the most common procedures. The overall success rate and recurrence rate of RFCA were 88.8% and 6.1% respectively. Complications occurred in 50 patients (4.2%) with 1 death (0.08%). RFCA of AVNRT or AVRT rather than other arrhythmias (Odd ratio 11.46, 95% confidence interval 8.14-16.15, p0.001) and adult rather than pediatric patients (Odd ratio for age 1.007, 95% confidence interval 1.003-1.011, p0.001) were independent predictors for successful RFCA.RFCA of cardiac arrhythmia in our institution is safe and effective.

The prevalence and predictors of postoperative sinus rhythm in patients undergoing a radiofrequency ablation maze operation and mitral valve surgery were assessed in 63 patients of whom 54 (86%) were in permanent atrial fibrillation. Operative mortality was 3.17%. At a median follow-up of 18 months, 54 (88.5%) patients were in sinus rhythm and 7 (11.5%) were in atrial fibrillation. The probability of sinus rhythm at 30 months was 92%. Left atrial diameter was the most significant prognostic factor for sinus rhythm on multivariate proportional-hazard regression analysis. The cutoff value of preoperative left atrial diameter for predicting persistent atrial fibrillation at 6 months was 6 cm (100% sensitivity and 73.6% specificity). The radiofrequency ablation maze operation can be performed in addition to mitral surgery with a high rate of successful conversion to sinus rhythm. Preoperative left atrial diameter < 6 cm is an important prognostic factor for sinus rhythm conversion.

The incidence of arrhythmic complications in Thai patients with acute coronary syndromes (ACS) has not been previously reported. The present study results will serve as the local database for future studies.To evaluate the incidence of arrhythmic complications in ASC in Thai patients and to identify factors that may affect arrhythmia complications in ACS patients.Data collected from 9,373 patients from the Thai acute coronary syndrome registry (TACSR) were analyzed. This registry includes patients who presented with ACS including ST elevation myocardial infarction (STEMI), non-ST elevation myocardial infarction (NSTEMI) and unstable angina (UA), within 14 days from the symptoms onset.395 (4.2%) patients with an ACS presented after cardiac arrest. These patients were noted to have significantly higher in-hospital mortality (50.1%). The incidence of serious cardiac arrhythmia complications in the TACSR was 16.6%. Among them, 62.7% were sustained VT/VE 31.5% had second or third degree AV block, and 5.8% has both VT/VF and AV Block. The incidence of VT was higher in the younger age group, while AV block and arrhythmic death were higher in the older aged patients. Arrhythmias complicating ACS were associated with increased mortality risk. Congestive heart failure (CHF) within the first 48 hours, current use of tobacco and cardiac troponin elevation were associated with significantly higher arrhythmic complications during hospitalization.Arrhythmias complicating ACS were associated with higher in hospital mortality. CHF within the first 48 hr, current tobacco use and cardiac troponin elevation were associated with significantly higher arrhythmic complications.

Brugada syndrome (BrS) is defined as presenting of type-1 Brugada pattern (BrP). BrS can also be induced by fever. We reported a high prevalence of fever induced BrS from the emergency department of Buriram hospital, Thailand. This study demonstrated the highest prevalence of fever induced BrS ever