2023 Consensus of Taiwan Society of Cardiology on the Pharmacological Treatment of Chronic Heart Failure.

The prevalence of heart failure is increasing, causing a tremendous burden on health care systems around the world. Although mortality rate of heart failure has been significantly reduced by several effective agents in the past 3 decades, yet it remains high in observational studies. More recently, several new classes of drugs emerged with significant efficacy in reducing mortality and hospitalization in chronic heart failure with reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF). To integrate these effective therapies and prioritize them in the management of Asian patients, Taiwan Society of Cardiology has recently appointed a working group to formulate a consensus of pharmacological treatment in patients with chronic heart failure. Based on most updated information, this consensus provides rationales for prioritization, rapid sequencing, and in-hospital initiation of both foundational and additional therapies for patients with chronic heart failure.

Observational study of dronedarone in Taiwanese patients with atrial fibrillation.

BACKGROUND/PURPOSE: Currently, data on the real-world use of dronedarone, an antiarrhythmic drug for atrial fibrillation (AF), are contradictory and often based on patient populations comprised of Caucasians. We prospectively investigated the efficacy and safety of dronedarone and risk factors related to treatment outcomes in a real-world use setting. METHODS: The prospective, observational, single-arm, multi-center study included a total of 824 Taiwanese patients with a diagnosis of paroxysmal or persistent AF and receiving dronedarone treatment. Risk factors analysis, efficacy, and safety of dronedarone were assessed with a follow-up of six months. RESULTS: Of the 824 patients enrolled (mean age, 75.3 ± 7.2 years), 95.2% had at least one cardiovascular risk factor. An increase in the proportion of patients with sinus rhythm following treatment was seen (52.1% at baseline vs. 67.4% at 6 months). A decrease in the mean duration of AF episodes (388.4 min vs. 62.3 min) and an increase in total AFEQT (65.4 ± 16.2 vs. 74.0 ± 11.8) were also observed after 6 months of treatment. Females, those under the age of 75, and those with symptomatic AF had higher odds of treatment success. At 6 months, 10.5% of patients reported treatment-related AEs. However, only 0.2% of the AEs were both severe in nature and causally related to dronedarone. CONCLUSION: This six-month study showed dronedarone to be relatively safe and efficacious and to improve quality-of-life in Taiwanese patients with atrial fibrillation. Odds of treatment success were related to the patient's gender, age, and AF type.

A performance guide for major risk factors control in patients with atherosclerotic cardiovascular disease in Taiwan.

Atherosclerotic cardiovascular disease (ASCVD), including coronary artery disease, cerebrovascular disease, and peripheral artery disease, carries a high morbidity and mortality. Risk factor control is especially important for patients with ASCVD to reduce recurrent cardiovascular events. Clinical guidelines have been developed by the Taiwan Society of Cardiology, Taiwan Society of Lipids and Atherosclerosis, and Diabetes Association of Republic of China (Taiwan) to assist health care professionals in Taiwan about the control of hypertension, hypercholesterolemia and diabetes mellitus. This article is to highlight the recommendations about blood pressure, cholesterol, and sugar control for ASCVD. Some medications that are beneficial for ASCVD were also reviewed. We hope the clinical outcomes of ASCVD can be improved in Taiwan through the implementation of these recommendations.

RETRACTED: Deficiency of a novel gene, Yulink, predisposes to heart failure and ventricular arrhythmia.

Heart failure is a major cardiovascular disease and is associated with significant morbidity and mortality. Sudden cardiac death (SCD) in heart failure is a disastrous cardiovascular phenomenon. However, few studies have examined the genetic background that determines susceptibility to heart failure and SCD. We found that deficiency of a newly identified gene, Yulink, promoted cardiac alternans in zebrafish cardiomyocytes, and genetic knockdown (KD) resulted in pericardial edema, decreased cardiac output, and premature ventricular contractions. Yulink KD morphants exhibited irregular action potentials, slower Ca2+ reuptake, and alternans of Ca2+ transients and action potential duration, which are hallmarks for SCD susceptibility in heart failure. Similarly, KD of Yulink in mouse cardiomyocytes disrupted Ca2+ reuptake, reduced the expression of cardiac Serca2, and resulted in a reduction in peroxisome proliferator-activated receptor (PPAR)γ activity. Expression of Serca2 was up-regulated by PPARγ agonists and down-regulated by PPARγ-short hairpin RNA KD, suggesting that Yulink regulates Serca2 expression through PPARγ. Finally, Yulink and Serca2 were down-regulated in ventricular samples of hearts from patients with heart failure due to dilated cardiomyopathy. Our results highlight the interaction of Yulink with PPARγ in regulating Serca2 expression and suggest a mechanistic role of the Yulink in the development of human heart failure and SCD.-Tsai, C.-T., Kuo, M.-W., Lin, J.-L., Yu, A. L., Yu, J. Deficiency of a novel gene, Yulink, predisposes to heart failure and ventricular arrhythmia.

Cryoablation with an 8-mm tip catheter in the treatment of atrioventricular nodal re-entrant tachycardia: results from a randomized controlled trial (CRYOABLATE).

AIMS: This was a randomized controlled study performed to compare 8 mm-tip catheter cryoablation (CRYO) with radiofrequency ablation (RFA) in treating atrioventricular nodal re-entrant tachycardia (AVNRT). METHODS AND RESULTS: A total of 158 patients (103 women, mean age 48.9 ± 14.1) with symptomatic AVNRT (140 typical; 18 atypical) were randomized to undergo CRYO with an 8 mm-tip catheter (n = 80) or RFA (n = 78). The primary endpoint was a composite of acute procedural failure, inadvertent permanent atrioventricular block (AVB) and recurrence at 12 months. No significant difference was observed between CRYO and RFA groups in primary endpoint (7.5 vs. 11.5%; P = 0.764), 12-month recurrence rate (3.8 vs. 1.3%; P = 0.358), inadvertent permanent AVB (0 vs. 1.3%; P = 0.307), and acute procedural failure (3.7 vs. 9%; P = 0.128). In patients with acute procedure failure, success was achieved in 5 of 7 patients (71.4%) in RFA group and 2 of 3 patients (66.7%) in CRYO group on cross-over. There was no significant difference in procedural duration between CRYO and RFA groups (72.4 ± 41.6 vs. 63.7 ± 29.8 min; P = 0.13), but fluoroscopic duration in CRYO group was significantly shorter (3.4 ± 6.3 vs. 6.7 ± 7.4 min; P = 0.005). Patient pain score (2.7 ± 2.7 vs. 4.6 ± 2.7; P < 0.001) and operator stress score (2.3 ± 1.3 vs. 4.9 ± 2; P < 0.001) were significantly lower in CRYO group. CONCLUSIONS: Cryoablation with an 8 mm-tip catheter is shown to be comparable to RFA in treating AVNRT in terms of efficacy and safety. Additional advantages in CRYO include shorter fluoroscopic time, lower patient pain perception, and operator stress level.

2019 Focused Update of the Guidelines of the Taiwan Society of Cardiology for the Diagnosis and Treatment of Heart Failure.

Heart failure is a growing epidemic, especially in Taiwan because of the aging population. The 2016 Taiwan Society of Cardiology - Heart Failure with reduced Ejection Fraction (TSOC-HFrEF) registry showed that the guideline-recommended therapies were prescribed suboptimally both at the time of hospital discharge and during follow-up. We, therefore, conducted this 2019 focused update of the guidelines of the Taiwan Society of Cardiology for the diagnosis and treatment of heart failure to reinforce the importance of new diagnostic and therapeutic modalities of heart failure. The 2019 focused update discusses new diagnostic criteria, pharmacotherapy, non-pharmacological management, and certain co-morbidities of heart failure. Angiotensin receptor neprilysin inhibitor and If channel inhibitor is introduced as new and recommended medical therapies. Latest criteria of cardiac resynchronization therapy, implantable cardioverter-defibrillator, heart transplantation, and ventricular assist device therapy are reviewed in the non-pharmacological management chapter. Co-morbidities in heart failure are discussed including chronic kidney disease, diabetes, chronic obstructive pulmonary disease, and sleep-disordered breathing. We also explain the adequate use of oxygen therapy and non-invasive ventilation in heart failure management. A particular chapter for chemotherapy-induced cardiac toxicity is incorporated in the focused update to emphasize the importance of its recognition and management. Lastly, implications from the TSOC-HFrEF registry and post-acute care of heart failure are discussed to highlight the importance of guideline-directed medical therapy and the benefits of multidisciplinary disease management programs. With guideline recommendations, we hope that the management of heart failure can be improved in our society.

2018 Guidelines of the Taiwan Society of Cardiology, Taiwan Society of Emergency Medicine and Taiwan Society of Cardiovascular Interventions for the management of non ST-segment elevation acute coronary syndrome.

In Taiwan, the incidence of non-ST segment elevation acute coronary syndrome (NSTE-ACS) continues to increase in recent years. The purpose of this guideline is to help health care professionals in Taiwan to use adequate tests and treatments for management of NSTE-ACS. For rapid diagnosis, in addition to history and physical examination, 0/3 h rapid diagnosis protocol with high sensitivity cardiac troponin assay is recommended in this guideline. Dual antiplatelet and anticoagulation therapies are important parts in the initial treatment. Risk stratification should be performed to identify high risk patients for early coronary angiography. Through evaluation of the coronary anatomy and other clinical factors, the decision for coronary revascularization, either by percutaneous coronary intervention or coronary artery bypass grafting, should be decided by the heart team. The duration of dual antiplatelet therapy should be given for at least 12 months after discharge. Other secondary preventive medications are also recommended for long term use.

Atrial flutter/fibrillation in patients receiving transcatheter closure of atrial septal defect.

BACKGROUND/PURPOSE: Atrial flutter/fibrillation (AFL/Af) is a common late complication in atrial septal defect (ASD) patients even after occluder implantation. We try to delineate the risk factors of persistent AFL/Af. METHODS: From 1998 to 2010, all patients older than 18 years of age who received ASD occluder implantation in our hospital were enrolled, and their records were retrospectively reviewed. In addition, renin-angiotensin system gene polymorphisms including angiotensinogen gene, A1166C polymorphism on the angiotensin II type I receptor gene, and insertion/deletion (I/D) patterns on the angiotensin-converting enzyme gene were checked using direct sequencing. RESULTS: A total of 517 patients (male/female 127/390) were enrolled. The mean age of patients receiving occluder deployment was 41.5 ± 14.5 years. Prior to occluder deployment, 3.9% of patients had persistent Af, 3.1% of patients had paroxysmal Af, and 0.8% had AFL. After a follow-up of 1894 patient-years, 3.5% had persistent Af and 1.9% of patients had paroxysmal Af. The greatest risk factors of AFL/Af genesis included age, occluder size, presence of multiple ASDs, and underlying thyroid or mitral valve disorder (p < 0.001, p < 0.001, p = 0.033, p = 0.016, and p = 0.012, respectively). Preoperative AFL/Af status is the most important factor in determining AFL/Af resolution and progression after an intervention. The renin-angiotensin system gene polymorphisms had no association with AFL/Af genesis, and progression or resolution after intervention. CONCLUSION: AFL/Af is common after ASD occluder implantation, and predisposed by older age, larger and multiple ASDs, and underlying disorders. Preoperative atrial arrhythmia status is the most important predictor of AFL/Af progression or resolution. Renin-angiotensin system gene polymorphisms had no association with AFL/Af.

SYNTAX Score of Infarct-Related Artery Other Than the Number of Coronary Balloon Inflations and Deflations as an Independent Predictor of Contrast-Induced Acute Kidney Injury in Patients with ST-Segment Elevation Myocardial Infarction.

BACKGROUND: Although remote ischemic post-conditioning (RIPC) has been shown to prevent contrast-induced acute kidney injury (CIAKI) in patients with acute coronary syndrome, its efficacy in patients with ST-segment elevation myocardial infarction (STEMI) remains unclear. We examined the relationship among balloon inflations and deflations (BID) times, SYNTAX score of infarction-related artery (SI), periprocedural complications, and CIAKI in STEMI patients undergoing primary percutaneous coronary intervention (pPCI). METHODS: Patients with STEMI undergoing pPCI with Mehran risk score (MRS) ≥ 5 were enrolled between February 2007 and September 2012. The study end point was the development of CIAKI. RESULTS: Of 206 patients, the median age was 65 years [interquartile range (IQR): 55-77] with 72.8% male and Mehran risk score (MRS) 8 (IQR: 6-12). Receiver operating characteristic curve showed that BID times > 9 times or SI > 10 was the best cut-off associated with CIAKI. In univariate analysis, significant association with CIAKI existed in BID > 9 times [odds ratio (OR): 3.106, 95% confidence interval (CI): 1.284-7.513, p = 0.012] and SI > 10 (OR: 3.909, 95% CI: 1.570-9.735, p = 0.003). Other variables associated with CIAKI included creatinine, hemoglobin, angiotensin converting enzyme inhibitor or angiotensin receptor blocker use at discharge. In multivariate analysis, SI > 10 remained an independent predictor of CIAKI in different adjustment model, even on top of MRS (adjusted OR: 3.498, 95% CI: 1.086-11.268, p = 0.036). CONCLUSIONS: Vascular complexity of infarct-related artery rather than higher BID times (> 9) was the major determinant of the development of CIAKI after pPCI in STEMI patients.

The 2017 Focused Update of the Guidelines of the Taiwan Society of Cardiology (TSOC) and the Taiwan Hypertension Society (THS) for the Management of Hypertension.

Hypertension (HT) is the most important risk factor for cardiovascular diseases. Over the past 25 years, the number of individuals with hypertension and the estimated associated deaths has increased substantially. There have been great debates in the past few years on the blood pressure (BP) targets. The 2013 European Society of Hypertension and European Society of Cardiology HT guidelines suggested a unified systolic BP target of 140 mmHg for both high-risk and low-risk patients. The 2014 Joint National Committee report further raised the systolic BP targets to 150 mmHg for those aged ≥ 60 years, including patients with stroke or coronary heart disease, and raised the systolic BP target to 140 mmHg for diabetes. Instead, the 2015 Hypertension Guidelines of the Taiwan Society of Cardiology and the Taiwan Hypertension Society suggested more aggressive BP targets of < 130/80 mmHg for patients with diabetes, coronary heart disease, chronic kidney disease with proteinuria, and atrial fibrillation patients on antithrombotic therapy. Based on the main findings from the Systolic Blood Pressure Intervention Trial (SPRINT) and several recent meta-analyses, the HT committee members of the Taiwan Society of Cardiology and the Taiwan Hypertension Society convened and finalized the revised BP targets for management of HT. We suggested a new systolic BP target to < 120 mmHg for patients with coronary heart disease, chronic kidney disease with an eGFR of 20-60 ml/min/1.73 m2, and elderly patients aged ≥ 75 years, using unattended automated office BP measurement. When traditional office BP measurement is applied, we suggested BP target of < 140/90 mmHg for elderly patients with an age ≥ 75 years. Other BP targets with traditional office BP measurement remain unchanged. With these more aggressive BP targets, it is foreseeable that the cardiovascular events will decrease substantially in Taiwan.

One-Year Outcomes of Acute Decompensated Systolic Heart Failure in Taiwan: Lessons from TSOC-HFrEF Registry.

BACKGROUND: Heart failure (HF) is a global health problem. The Taiwan Society of Cardiology-Heart Failure with reduced Ejection Fraction (TSOC-HFrEF) registry was a multicenter, observational survey of patients admitted with HFrEF in Taiwan. The aim of this study was to report the one-year outcome in this large-cohort of hospitalized patients presenting with acute decompensated HFrEF. METHODS: Patients hospitalized for acute HFrEF were recruited in 21 hospitals in Taiwan. A total of 1509 patients were enrolled into the registry by the end of October 2014. Clinical status, readmission rates and dispensed medications were collected and analyzed 1 year after patient index hospitalization. RESULTS: Our study indicated that re-hospitalization rates after HFrEF were 31.9% and 38.5% at 6 and 12 months after index hospitalization, respectively. Of these patients, 9.7% of them were readmitted more than once. At 6 and 12 months after hospital discharge, all-cause mortality rates were 9.5% and 15.9%, respectively, and cardiovascular mortality rates were 6.8% and 10.5%, respectively. Twenty-three patients (1.5%) underwent heart transplantation. During a follow-up period of 1 year, 46.4% of patients were free from mortality, HF re-hospitalization, left ventricular assist device use and heart transplantation. At the conclusion of follow-up, 57.5% of patients were prescribed either with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers; also, 66.3% were prescribed with beta-blockers and 40.8% were prescribed with mineralocorticoid receptor antagonists. CONCLUSIONS: The TSOC-HFrEF registry showed evidence of suboptimal practice of guideline-directed medical therapy and high HF re-hospitalization rate in Taiwan. The one-year mortality rate of the TSOC-HFrEF registry remained high. Ultimately, our data indicated a need for further improvement in HF care.

Next-generation sequencing of nine atrial fibrillation candidate genes identified novel de novo mutations in patients with extreme trait of atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. Genome-wide association studies (GWAS) have identified common variants in nine genomic regions associated with AF (KCNN3, PRRX1, PITX2, WNT8A, CAV1, C9orf3, SYNE2, HCN4 and ZFHX3 genes); however, the genetic variability of these risk variants does not explain the entire genetic susceptibility to AF. Rare variants missed by GWAS may also contribute to genetic risk of AF. METHODS: We used an extreme trait design to sequence carefully selected probands with extreme phenotypes and their unaffected parents to identify rare de novo variants or mutations. Based on the hypothesis that common and rare variants may colocate in the same disease susceptibility gene, we used next-generation sequencing to sequence these nine published AF susceptibility genes identified by GWAS (a total of 179 exons) in 20 trios, 200 unrelated patients with AF and 200 non-AF controls. RESULTS: We identified a novel mutation in the 5' untranslated region of the PITX2 gene, which localised in the transcriptionally active enhancer region. We also identified one missense exon mutation in KCNN3, two in ZFHX3 and one in SYNE2. None of these mutations were present in other unrelated patients with AF, healthy controls, unaffected parents and are thus novel and de novo (p<10(-4)). Functional study showed that the mutation in the 5' untranslated region of the PITX2 gene significantly downregulated PITX2 expression in atrial myocytes, either in basal condition or during rapid pacing. In silico analysis showed that the missense mutation in ZFHX3 results in damage of the ZFHX3 protein structure. CONCLUSIONS: The genetic architecture of subjects with extreme phenotypes of AF is similar to that of rare or Mendelian diseases, and mutations may be the underlying cause.

2016 Guidelines of the Taiwan Heart Rhythm Society and the Taiwan Society of Cardiology for the management of atrial fibrillation.

Atrial fibrillation (AF) is the most common sustained arrhythmia. Both the incidence and prevalence of AF are increasing, and the burden of AF is becoming huge. Many innovative advances have emerged in the past decade for the diagnosis and management of AF, including a new scoring system for the prediction of stroke and bleeding events, the introduction of non-vitamin K antagonist oral anticoagulants and their special benefits in Asians, new rhythm- and rate-control concepts, optimal endpoints of rate control, upstream therapy, life-style modification to prevent AF recurrence, and new ablation techniques. The Taiwan Heart Rhythm Society and the Taiwan Society of Cardiology aimed to update the information and have appointed a jointed writing committee for new AF guidelines. The writing committee members comprehensively reviewed and summarized the literature, and completed the 2016 Guidelines of the Taiwan Heart Rhythm Society and the Taiwan Society of Cardiology for the Management of Atrial Fibrillation. This guideline presents the details of the updated recommendations, along with their background and rationale, focusing on data unique for Asians. The guidelines are not mandatory, and members of the writing committee fully realize that treatment of AF should be individualized. The physician's decision remains most important in AF management.

TSOC-HFrEF Registry: A Registry of Hospitalized Patients with Decompensated Systolic Heart Failure: Description of Population and Management.

INTRODUCTION: Heart failure (HF) is a medical condition with a rapidly increasing incidence both in Taiwan and worldwide. The objective of the TSOC-HFrEF registry was to assess epidemiology, etiology, clinical management, and outcomes in a large sample of hospitalized patients presenting with acute decompensated systolic HF. METHODS: The TSOC-HFrEF registry was a prospective, multicenter, observational survey of patients presenting to 21 medical centers or teaching hospitals in Taiwan. Hospitalized patients with either acute new-onset HF or acute decompensation of chronic HFrEF were enrolled. Data including demographic characteristics, medical history, primary etiology of HF, precipitating factors for HF hospitalization, presenting symptoms and signs, diagnostic and treatment procedures, in-hospital mortality, length of stay, and discharge medications, were collected and analyzed. RESULTS: A total of 1509 patients were enrolled into the registry by the end of October 2014, with a mean age of 64 years (72% were male). Ischemic cardiomyopathy and dilated cardiomyopathy were diagnosed in 44% and 33% of patients, respectively. Coronary artery disease, hypertension, diabetes, and chronic renal insufficiency were the common comorbid conditions. Acute coronary syndrome, non-compliant to treatment, and concurrent infection were the major precipitating factors for acute decompensation. The median length of hospital stay was 8 days, and the in-hospital mortality rate was 2.4%. At discharge, 62% of patients were prescribed either angiotensin-converting enzyme-inhibitors or angiotensin receptor blockers, 60% were prescribed beta-blockers, and 49% were prescribed mineralocorticoid receptor antagonists. CONCLUSIONS: The TSOC-HFrEF registry provided important insights into the current clinical characteristics and management of hospitalized decompensated systolic HF patients in Taiwan. One important observation was that adherence to guideline-directed medical therapy was suboptimal.

Primary prevention of atrial fibrillation with angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in patients with end-stage renal disease undergoing dialysis.

Current evidence suggests that angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) reduce the incidence of new atrial fibrillation (AF) in a variety of clinical conditions, including the treatment of left ventricular dysfunction or hypertension. Here we assessed whether ACEIs and ARBs could decrease incidence of new-onset AF in patients with end-stage renal disease (ESRD). We identified patients from the Registry for Catastrophic Illness, a nation-wide database encompassing almost all of the patients receiving dialysis therapy in Taiwan from 1995 to 2008. Propensity score matching and Cox proportional hazards regression models were used to estimate hazard ratios for new-onset AF. Among 113,186 patients, 13% received ACEIs, 14% received ARBs therapy, and 9% received ACEIs or ARBs alternatively. After a median follow-up of 1524 days, the incidence of new-onset AF significantly decreased in patients treated with ACEIs (hazard ratio 0.587, 95% confidence interval 0.519-0.663), ARBs (0.542, 0.461-0.637), or ACEIs/ARBs (0.793, 0.657-0.958). The prevention of new-onset AF was significantly better in patients taking longer duration of ACEI or ARB therapy. The effect remained robust in subgroup analyses. Thus both ACEIs and ARBs appear to be effective in the primary prevention of AF in patients with ESRD. Hence, renin-angiotensin system inhibition may be an emerging treatment target for the primary prevention of AF.

Prevalence and prognosis of Brugada electrocardiogram patterns in an elderly Han Chinese population: a nation-wide community-based study (HALST cohort).

AIMS: The exact world-wide prevalence of Brugada electrocardiogram (ECG) pattern is still unclear, especially in adults aged 55 years and older. METHODS AND RESULTS: The study was conducted as part of the Healthy Aging Longitudinal Study in Taiwan (HALST). Using a stratified random sampled method, a sample of community-dwelling subjects was recruited from seven community-based regions across Taiwan. All enrolled subjects were follow-up annually and cause of death was documented by citizen death records. A total of 5214 subjects were enrolled (male/female: 2530/2684) with a mean age of 69 ± 8 years. The overall prevalence of Brugada ECG patterns was 3.32%. Four subjects carried spontaneous Type 1 Brugada ECG pattern, 68 carried Type 2, and 101 carried Type 3. Compared with the world-wide average prevalence of Brugada ECG patterns, the prevalence of spontaneous Type 1 Brugada ECG pattern in subjects from the HALST cohort was similar (0.077 vs. 0.07%) and the combined prevalence of Types 2 and 3 Brugada ECG pattern was 10 times higher (3.24 vs. 0.28%) even the mean age of study subjects was significantly higher (69 ± 8 vs. 35 ± 8, P < 0.001). However, all-cause mortality and cardiac mortality rates were not significantly different between subjects with and without Brugada ECG patterns during the 4-year follow-up (log-rank test, P = 0.21, 0.32, respectively). CONCLUSION: The prevalence of Brugada ECG pattern in adults aged 55 years and older in Taiwan was higher than the average world-wide prevalence but was not associated with increased mortality.

Acute effects of biventricular pacing in heart failure patients with a normal ejection fraction and mechanical dyssynchrony.

OBJECTIVES: We tested the acute effects of resynchronization in heart failure patients with a normal (>50%) left ventricular (LV) ejection fraction (HFNEF) and mechanical dyssynchrony. METHODS: Twenty-four HFNEF patients (72 ± 6 years, 5 male) with mechanical dyssynchrony (standard deviation of electromechanical time delay among 12 LV segments >35 ms) were studied with temporary pacing catheters in the right atrium, LV, and right ventricle (RV), and high-fidelity catheters for pressure recording. Using selected atrioventricular (AV) intervals of 60, 90, 120, 150, and 180 ms to optimize transmitral flow during simultaneous biventricular pacing, the RV-LV (VV) interval was then evaluated at RV30, RV15, 0, LV15, LV30, and LV45 (RV or LV indicates which ventricle was paced first, the number indicates by how many ms). RESULTS: During simultaneous pacing, longer AV intervals were associated with improved LV pressure-derivative minimums and increased aortic pressures (p < 0.05 vs. normal sinus rhythm). In the VV interval from RV30 to LV45, there was a graded increase in the aortic velocity time integral and a decrease in dyssynchrony during simultaneous or LV-first pacing (p < 0.05 vs. normal sinus rhythm). CONCLUSIONS: For HFNEF patients with mechanical dyssynchrony, acute simultaneous biventricular or LV-first pacing with longer AV intervals reduced mechanical dyssynchrony and improved diastolic and systolic hemodynamics.

Unique clinical characteristics and SCN5A mutations in patients with Brugada syndrome in Taiwan.

BACKGROUND/PURPOSE: Brugada syndrome (BrS) is a hereditable sudden cardiac death (SCD). Mutations in the SCN5A gene (the most common BrS-causing gene) are responsible for 20-25% of this disease in Caucasian populations. However, the prevalence of SCN5A mutations in patients with BrS in the Chinese Han population in Taiwan remains unknown. Therefore, in this study, we investigated the prevalence of the SCN5A mutation in the largest BrS cohort in Taiwan. METHODS: We consecutively enrolled 47 unrelated patients with BrS from medical centers and hospitals in Taiwan between 2000 and 2010. Mutations within all the 27 translated exons, and exon-intron boundaries of the SCN5A-encoded cardiac sodium channel were screened in all patients with BrS using direct sequencing. A total of 500 unrelated healthy volunteers with a normal electrocardiogram were genotyped as a control group. RESULTS: SCN5A genetic variants were identified in 14 of the 47 patients with BrS and four of the 14 patients with BrS had missense mutations (1651 G>A, 1776 C>G, 3578 G>A). The prevalence rate of SCN5A mutations was approximately 8% (4/47), which was significantly lower than that reported in Caucasian populations (20-25%; p = 0.0007). The average age of these 14 BrS patients with SCN5A variants at diagnosis (12 men and 2 women) was 40 ± 13 years. Four patients experienced SCD, and six presented with seizure or syncope. Only three patients (3/14, 21.4%) had a family history of SCD. CONCLUSION: The prevalence of SCN5A mutations in the Chinese Han population in Taiwan may be lower than that reported in the Caucasian populations. In addition, most patients with BrS did not have a family history of SCD.

Association of Small-Conductance Calcium-Activated Potassium Channels and Atrial Fibrillation - How Far Have We Gone?

UNLABELLED: Atrial fibrillation (AF) is the most common sustained and most important arrhythmia in clinical practice. The mechanisms underlying AF initiation and maintenance are known to be complex and heterogeneous. The general understanding of the detailed molecular basis of AF is still incomplete. Recently, these is increasing evidence that small conductance calcium-activated potassium (SK) channels are associated with atrial action potential repolarization and the pathogenesis of AF. Although the functional role of SK channels in the genesis of AF is not entirely clear, new insights into the basic pathophysiological mechanism of AF have been provided. Besides, genome-wide association studies also implicate that genes coding for SK channels are related to the risk of developing AF. This article reviews recent work on the association of SK channels and AF, genetic studies of SK channels, and discuss future investigation and developments regarding this field. KEY WORDS: Atrial fibrillation; Genetics; Small conductance calcium-activated potassium channels.