Prevalence of Electrocardiographic Findings Suggestive of Sudden Cardiac Death Risk in 10,867 Apparently Healthy Young Korean Men

ECG evaluation in 11 949 Italian teenagers: results of screening in secondary school

AIM

There is lack of evidence regarding the screening role of ECG for sudden cardiac death (SCD) prevention. Our aim was to evaluate the prevalence of ECG abnormalities among teenagers according to sport participation and competitive status.

METHODS

Eleven thousand nine hundred and forty-nine Italian pupils from 179 secondary schools (13-19 years) were consecutively enrolled. ECG abnormalities were divided into minor and major. Medical history, clinical examination and sport activity information were acquired. Further evaluations were suggested in case of major ECG abnormalities. Follow-up was performed at 2 years.

RESULTS

N = 1945 (16%) pupils had ECG abnormalities. Major ECG abnormalities were detected in 13% of the cohort, minor in 34%. ECG abnormalities were more common in nonathletes compared with athletes. A diagnosis of cardiac disease was reached in 25 (1.6%) of the pupils with major ECG abnormalities.

CONCLUSION

ECG abnormalities are common among young populations and more prevalent in nonathletes. Among pupils with major ECG abnormalities 1.6% had a cardiac disease diagnosis. Our results are in line with the data supporting ECG screening in the general young population.

Epidemiology and risk factors of sudden cardiac arrest

PURPOSE OF REVIEW

Sudden cardiac arrest (SCA) remains a major health burden around the globe, most often occurring in the community (out-of-hospital cardiac arrest [OHCA]). SCA accounts for 15-20% of all natural deaths in adults in the USA and Western Europe, and up to 50% of all cardiovascular deaths. To reduce this burden, more knowledge is needed about its key facets such as its incidence in various geographies, its risk factors, and the populations that may be at risk.

RECENT FINDINGS

SCA results from a complex interaction of inherited and acquired causes, specific to each individual. Resolving this complexity, and designing personalized prevention and treatment, requires an integrated approach in which big datasets that contain all relevant factors are collected, and a multimodal analysis. Such datasets derive from multiple data sources, including all players in the chain-of-care for OHCA. This recognition has led to recently started large-scale collaborative efforts in Europe.

SUMMARY

Our insights into the causes of SCA are steadily increasing thanks to the creation of big datasets dedicated to SCA research. These insights may be used to earlier recognize of individuals at risk, the design of personalized methods for prevention, and more effective resuscitation strategies for OHCA.

The 10-Year Prognosis and Prevalence of Brugada-Type Electrocardiograms in Elderly Women: A Longitudinal Nationwide Community-Based Prospective Study

BACKGROUND

Brugada syndrome is a disorder associated with sudden cardiac death and characterized by an abnormal electrocardiogram (ECG). Previous studies were predominantly conducted in men, and the data on long-term prognosis are limited. Information about women, especially elderly women, is lacking.

OBJECTIVE

The aim of this study was to investigate the long-term prognosis of the Brugada ECG pattern in elderly women.

METHOD

We investigated the 10-year prognosis of the Brugada ECG pattern in elderly women in a nationwide community-based population in Taiwan. Community-dwelling women older than 55 years were prospectively recruited from December 2008 to March 2013 by a stratified random sampling method. All enrolled individuals were followed up annually until April 2019, and the cause of death was documented by citizen death records.

RESULTS

Among 2597 women, 60 (2.31%) had a Brugada-type ECG, and this prevalence was higher than the mean global prevalence of 0.23%. One woman had a type 1 ECG (0.04%), whereas 15 (0.58%) and 44 (1.70%) women had type 2 and type 3 ECG patterns, respectively. Cox survival analysis revealed that all-cause mortality and cardiac mortality were similar in the individuals with and without a Brugada-type ECG during a mean follow-up of 96.1 ± 20.5 months.

CONCLUSIONS

Our findings suggest that Brugada ECG patterns are not infrequent in elderly women but are not associated with increased risk of mortality in long-term follow-up; these findings may help reduce unnecessary anxiety for physicians, nurses, allied health caregivers, and patients.

Nonspecific intraventricular conduction delay is associated with future occurrence of atrial fibrillation in patients with structurally normal heart

BACKGROUND

We aimed to elucidate the long-term prognosis of nonspecific intraventricular conduction delay (NIVCD) in patients with structurally normal heart.

METHODS

We included 107,838 patients (age, 52.1 ± 15.5 years; men, 46.8%) who underwent electrocardiography in outpatient clinics or medical checkup (unmatched cohort). NIVCD was defined as QRS duration ≥110 ms without meeting the criteria for bundle branch block. Patients with structurally normal heart and sinus rhythm were assigned to the NIVCD and normal QRS groups according to propensity score with matching variables of age, sex, hypertension, and diabetes (matched cohort 1), and additional PR interval (matched cohort 2). Baseline characteristics, electrocardiographic parameters, and clinical outcomes were compared in the unmatched cohort and the matched cohort.

RESULTS

In the unmatched cohort, the frequencies of male sex and preexisting atrial fibrillation were significantly higher in the NIVCD group than in the normal QRS group. In matched cohort 1 (n = 690), the NIVCD group exhibited significant slower sinus rate and longer PR interval than the normal QRS group. In matched cohort 2 (n = 598), the cumulative incidence of atrial fibrillation was significantly higher in the NIVCD group than in the normal QRS group during a follow-up period of 8.8 ± 2.9 years. NIVCD significantly increased the risk for AF (hazard ratio, 2.571; 95% confidence interval, 1.074-6.156; p = 0.034).

CONCLUSIONS

It is suggested that NIVCD may be associated with future occurrence of atrial fibrillation in patients with structurally normal heart and sinus rhythm.

Present Status of Brugada Syndrome: JACC State-of-the-Art Review

The Brugada syndrome is an inherited disorder associated with risk of ventricular fibrillation and sudden cardiac death in a structurally normal heart. Diagnosis is based on a characteristic electrocardiographic pattern (coved type ST-segment elevation ≥2 mm followed by a negative T-wave in ≥1 of the right precordial leads V₁ to V₂), observed either spontaneously or during a sodium-channel blocker test. The prevalence varies among regions and ethnicities, affecting mostly males. The risk stratification and management of patients, principally asymptomatic, still remains challenging. The current main therapy is an implantable cardioverter-defibrillator, but radiofrequency catheter ablation has been recently reported as an effective new treatment. Since its first description in 1992, continuous achievements have expanded our understanding of the genetics basis and electrophysiological mechanisms underlying the disease. Currently, despite several genes identified, SCN5A has attracted most attention, and in approximately 30% of patients, a genetic variant may be implicated in causation after a comprehensive analysis.

Recent advances in the treatment of Brugada syndrome

INTRODUCTION

Brugada syndrome (BrS) is an inherited cardiac arrhythmia syndrome characterized by ST-segment elevation in right precordial ECG leads and associated with sudden cardiac death in young adults. The ECG manifestations of BrS are often concealed but can be unmasked by sodium channel blockers and fever. Areas covered: Implantation of a cardioverter defibrillator (ICD) is first-line therapy for BrS patients presenting with prior cardiac arrest or documented VT. A pharmacological approach to therapy is recommended in cases of electrical storm, as an adjunct to ICD and as preventative therapy. The goal of pharmacological therapy is to produce an inward shift to counter the genetically-induced outward shift of ion channel current flowing during the early phases of the ventricular epicardial action potential. This is accomplished by augmentation of I_Ca using □□adrenergic agents or phosphodiesterase III inhibitors or via inhibition of I_to. Radiofrequency ablation of the right ventricular outward flow tract epicardium is effective in suppressing arrhythmogenesis in BrS patients experiencing frequent appropriate ICD-shocks. Expert commentary: Understanding of the pathophysiology and approach to therapy of BrS has advanced considerably in recent years, but there remains an urgent need for development of cardio-selective and ion-channel-specific I_to blockers for treatment of BrS.

Inherited primary arrhythmia disorders: cardiac channelopathies and sports activity

Sudden cardiac death (SCD) in an apparently healthy individual is a tragedy. It is important to identify the cause of death and to prevent SCD in potentially at-risk family members. Inherited primary arrhythmia disorders are associated with exercise-related SCD. Despite the well-known benefits of exercise, exercise restriction has been a historical mainstay of therapy for these conditions. However, since familiarity with inherited arrhythmia conditions has increased and patients are often children and young adults, it is necessary to reassess the treatment guidelines regarding exercise constraints. The aim of this review is to analyze the risk of exercise-induced SCD in patients with inherited cardiac conditions and explore the challenges faced when advising patients about exercise limitations. We searched for publications on cardiac channelopathies in PubMed with the following medical subject headings (MeSH): "long QT syndrome"; "short QT syndrome"; "Brugada syndrome"; and "catecholaminergic polymorphic ventricular tachycardia". The abstracts of these articles were scanned, and articles of relevance, along with pertinent references, were read in full. The analysis was restricted to reports published in English. The findings of this analysis suggest that exercise with low-to-moderate cardiovascular demand may be possible under regular clinical follow-up in inherited primary arrhythmia disorders. Recent data show that patients with inherited primary arrhythmia disorders are at low risk for events once a comprehensive treatment program has been established. Recreational activity is likely safe for these individuals, with personalized management based on individual patient preferences and priorities.

Comparisons of clinical impacts on individuals with Brugada electrocardiographic patterns defined by ISHNE criteria or EHRA/HRS/APHRS criteria: a nationwide community-based study

INTRODUCTION

Identifying Brugada electrocardiographic pattern (BrP) early is crucial to prevent sudden cardiac death. Two different diagnostic criteria proposed by International Society for Holter and Noninvasive Electrocardiography (ISHNE) and Heart Rhythm Society/European Heart Rhythm Association/Asia-Pacific Heart Rhythm Society (HRS/EHRA/APHRS) were widely used in clinical practice. The difference in prevalence and prognosis of BrP by applying the two different criteria was never studied before.

METHODS

This study was prospectively conducted in a nationwide large-scale stratified random sampling community-based cohort (HALST) from Han Chinese population in Taiwan from December 2008 to December 2012. We compared the prevalence and prognosis of BrP defined by the two diagnostic criteria.

RESULTS

A total of 5214 adults were enrolled (2530 men) with mean age of 69.3 years. Four had spontaneous type 1 BrP (0.077%). By the HRS/EHRA/APHRS criteria, 68 individuals have type 2 BrP (1.30%) and 101 have type 3 BrP (1.94%) whereas by the ISHNE criteria, 46 individuals exhibited type 2 BrP (0.88%). When applying the ISHNE criteria, the number of individuals with BrP decreased by 71%. However, all-cause mortality and cardiovascular mortality were not different between individuals with or without BrP, irrespective of the criteria used.

CONCLUSIONS

The two different criteria may impact the diagnostic yield of individuals with BrP, but do not affect the prognosis of the individuals with BrP. Key messages Comparing with the use of HRS/EHRA/APHRS criteria, the number of individuals with Brugada ECG patterns was decreased by 71% when applying the ISHNE criteria. The prognosis of individuals with Brugada ECG patterns defined by 2012 ISHNE or 2013 HRS/EHRA/APHRS criteria were not different.

Prevalence of spontaneous Brugada ECG pattern recorded at standard intercostal leads: A meta-analysis

OBJECTIVE

Typical Brugada ECG pattern is the keystone in the diagnosis of Brugada syndrome. However, the exact prevalence remains unclear, especially in Asia. The present study was designed to systematically evaluate the prevalence of spontaneous Brugada ECG pattern recorded at standard leads.

METHODS

We searched the Medline, Embase and Chinese National Knowledge Infrastructure (CNKI) for studies of the prevalence of Brugada ECG pattern, published between Jan 1, 2003, and September 1, 2016. Pooled prevalence of type 1 and type 2-3 Brugada ECG pattern were estimated in a random-effects model, and group prevalence data by the characteristic of studies. Meta-regression analyses were performed to explore the potential sources of heterogeneity, and sensitivity analyses were conducted to assess the effect of each study on the overall prevalence.

RESULTS

Thirty-nine eligible studies involving 558,689 subjects were identified. Pooled prevalence of type 1 and 2-3 Brugada ECG pattern was 0.03% (95%CI, 0.01%-0.06%), and 0.42% (95%CI, 0.28%-0.59%), respectively. Regions, sample size, year of publication were the main source of heterogeneity. The prevalence of type 1 Brugada ECG pattern was higher in male, Asia, adult, patient, and fever subjects; but the relation between fever and type 2-3 Brugada ECG pattern was not significant. Sensitivity analysis showed that each study did not lonely affect the prevalence of type 1 and type 2-3 Brugada ECG pattern.

CONCLUSION

Brugada ECG pattern is not rare, especially preponderant in adult Asian males, and fever subjects. Clinical screening and further examination of Brugada syndrome in potential population need to be highlighted.

Frequency of different electrocardiographic abnormalities in a large cohort of Spanish workers

Aims

Our aim was to describe the electrocardiographic findings of a large sample of Spanish workers from several different employment sectors.

Methods and results

Between May 2008 and November 2010, 13 495 consecutive 12-lead resting electrocardiograms (ECGs) were obtained during health examinations of working adults aged 16-74 years in 5 cities in different regions of Spain. Of those, 13 179 ECGs suitable for interpretation were included in this study. All tracings were classified by the same cardiologist, according to the Minnesota Code criteria. The mean age of the sample was 40 years, and 73.4% were male. Frequencies of complete right bundle branch block, complete left bundle branch block, and left ventricular hypertrophy were 1.1, 0.2, and 3.6%, respectively. Major Q wave abnormalities were observed in 1.7% of the subjects, T wave abnormalities in 0.7%, early repolarization in 2.4%, and other ST segment abnormalities in 0.2%. Atrial fibrillation was present in 0.08% of the workers and atrial flutter in 0.02%. Frequencies of the Wolff-Parkinson-White pattern, Brugada pattern, long QT pattern, and short QT pattern were 0.2, 0.068, 0.038, and 0.015%, respectively.

Conclusion

This study shows the electrocardiographic findings of a large sample of Spanish workers from several different employment sectors. The frequencies of many ECG patterns related to an adverse prognosis (left ventricular hypertrophy, complete left bundle branch block, T wave abnormalities, ST segment abnormalities, and atrial fibrillation) were low.

Brugada syndrome: a fatal disease with complex genetic etiologies - still a long way to go

Brugada syndrome (BrS) is an arrhythmogenic disorder which was first described in 1992. This disease is a channelopathy characterized by ST-segment elevations in the right precordial leads and is susceptible to sudden death. BrS is a fatal disease with gender and age preferences. It occurs mainly in young male subjects with a structurally normal heart and silently progresses to sudden death with no significant symptoms. The prevalence of BrS has been reported in the ranges of 5–20 per 10 000 people. The disease is more prevalent in Asia. Nowadays, numerous variations in 23 genes have been linked to BrS since the first gene SCN5A has been associated with BrS in 1998. Not only can clinical specialists apply these discoveries in risk assessment, diagnosis and personal medicine, but also forensic pathologists can make full use of these variations to conduct death cause identification. However, despite the progress in genetics, these associated genes can only account for approximately 35% of the BrS cases while the etiology of the remaining BrS cases is still unexplained. In this review, we discussed the prevalence, the genes associated with BrS and the application of molecular autopsy in forensic pathology. We also summarized the present obstacles, and provided a new insight into the genetic basis of BrS.

International criteria for electrocardiographic interpretation in athletes: Consensus statement

Sudden cardiac death (SCD) is the leading cause of mortality in athletes during sport. A variety of mostly hereditary, structural or electrical cardiac disorders are associated with SCD in young athletes, the majority of which can be identified or suggested by abnormalities on a resting 12-lead electrocardiogram (ECG). Whether used for diagnostic or screening purposes, physicians responsible for the cardiovascular care of athletes should be knowledgeable and competent in ECG interpretation in athletes. However, in most countries a shortage of physician expertise limits wider application of the ECG in the care of the athlete. A critical need exists for physician education in modern ECG interpretation that distinguishes normal physiological adaptations in athletes from distinctly abnormal findings suggestive of underlying pathology. Since the original 2010 European Society of Cardiology recommendations for ECG interpretation in athletes, ECG standards have evolved quickly, advanced by a growing body of scientific data and investigations that both examine proposed criteria sets and establish new evidence to guide refinements. On 26-27 February 2015, an international group of experts in sports cardiology, inherited cardiac disease, and sports medicine convened in Seattle, Washington (USA), to update contemporary standards for ECG interpretation in athletes. The objective of the meeting was to define and revise ECG interpretation standards based on new and emerging research and to develop a clear guide to the proper evaluation of ECG abnormalities in athletes. This statement represents an international consensus for ECG interpretation in athletes and provides expert opinion-based recommendations linking specific ECG abnormalities and the secondary evaluation for conditions associated with SCD.

A meta-analytic review of prevalence for Brugada ECG patterns and the risk for death

BACKGROUND

The prevalence of Brugada ECG pattern (BrEP) is different in different regions, and its mean prevalence over the world is unknown. The risk of people with BrEP for death remains unknown. We performed a meta-analysis to determine the prevalence of BrEP and risk ratio (RR) for death.

METHODS

Relevant studies published between July 1, 2000 and August 20, 2016, which contain prevalence and RR for all-cause death and cardiac death, were included. The prevalence and RR are analyzed using meta-analysis.

RESULTS

We finally retrieved 24 studies of the prevalence for BrEP and 5 studies of the RR for all-cause death and cardiac death. The worldwide mean prevalence of BrEP is 0.4%, with highest in Asia (0.9%) and lowest in North America (0.2%). Additionally, the mean prevalence in male is 0.9%, whereas it is 0.1% in female. The RR of BrEP for all-cause death is 0.78 (95% confidence interval 0.45-1.37), and for cardiac death it is 0.92 (95% confidence interval 0.23-3.66).

CONCLUSION

The prevalence of BrEP is about 0.4% around the world with different prevalence in region and sex. Our study shows that BrEP may not be taken as a predictor of all-cause death and cardiac death.

Brugada Syndrome: Clinical, Genetic, Molecular, Cellular, and Ionic Aspects

Brugada syndrome (BrS) is an inherited cardiac arrhythmia syndrome first described as a new clinical entity in 1992. Electrocardiographically characterized by distinct coved type ST segment elevation in the right-precordial leads, the syndrome is associated with a high risk for sudden cardiac death in young adults, and less frequently in infants and children. The electrocardiographic manifestations of BrS are often concealed and may be unmasked or aggravated by sodium channel blockers, a febrile state, vagotonic agents, as well as by tricyclic and tetracyclic antidepressants. An implantable cardioverter defibrillator is the most widely accepted approach to therapy. Pharmacologic therapy is designed to produce an inward shift in the balance of currents active during the early phases of the right ventricular action potential (AP) and can be used to abort electrical storms or as an adjunct or alternative to device therapy when use of an implantable cardioverter defibrillator is not possible. Isoproterenol, cilostazol, and milrinone boost calcium channel current and drugs like quinidine, bepridil, and the Chinese herb extract Wenxin Keli inhibit the transient outward current, acting to diminish the AP notch and thus to suppress the substrate and trigger for ventricular tachycardia or fibrillation. Radiofrequency ablation of the right ventricular outflow tract epicardium of patients with BrS has recently been shown to reduce arrhythmia vulnerability and the electrocardiographic manifestation of the disease, presumably by destroying the cells with more prominent AP notch. This review provides an overview of the clinical, genetic, molecular, and cellular aspects of BrS as well as the approach to therapy.

Electrocardiographic T Wave Abnormalities and the Risk of Sudden Cardiac Death: The Finnish Perspective

The identification of patients at risk for sudden cardiac death (SCD) is still a significant challenge to clinicians and scientists. Noninvasive identification of high-risk patients has been of great interest, and several ventricular depolarization and repolarization abnormalities in the standard 12-lead electrocardiogram (ECG) have been associated with increased vulnerability to lethal ventricular arrhythmias. Several benign and pathological conditions can induce changes in repolarization detected as alteration of the ST segment or T wave. Changes in the ST segment and T waves can be early markers of an underlying cardiovascular disease, and even minor ST-T abnormalities have predicted reduced survival and increased risk of SCD in the adult population. In this review, we will discuss the current knowledge of the SCD risk with standard 12-lead ECG T wave abnormalities in the general population, and possible T wave changes in various cardiac conditions predisposing to SCD.

Prevalence and prognostic significance of T-wave inversions in right precordial leads of a 12-lead electrocardiogram in the middle-aged subjects

BACKGROUND

T-wave inversion in right precordial leads V(1) to V(3) is a relatively common finding in a 12-lead ECG of children and adolescents and is infrequently found also in healthy adults. However, this ECG pattern can also be the first presentation of arrhythmogenic right ventricular cardiomyopathy. The prevalence and prognostic significance of T-wave inversions in the middle-aged general population are not well known.

METHODS AND RESULTS

We evaluated 12-lead ECGs of 10 899 Finnish middle-aged subjects (52% men, mean age 44 ± 8.5 years) recorded between 1966 and 1972 for the presence of inverted T waves and followed the subjects for 30 ± 11 years. Primary end points were all-cause mortality, cardiac mortality, and arrhythmic death. T-wave inversions in right precordial leads V(1) to V(3) were present in 54 (0.5%) of the subjects. In addition, 76 (0.7%) of the subjects had inverted T waves present only in leads other than V(1) to V(3). Right precordial T-wave inversions did not predict increased mortality (not significant for all end points). However, inverted T waves in leads other than V(1) to V(3) were associated with an increased risk of cardiac and arrhythmic death (P<0.001 for both).

CONCLUSIONS

T-wave inversions in right precordial leads are relatively rare in the general population, and are not associated with adverse outcome. Increased mortality risk associated with inverted T waves in other leads may reflect the presence of an underlying structural heart disease.

Prevalence of electrocardiographic abnormalities in an unselected young male multi-ethnic South-East Asian population undergoing pre-participation cardiovascular screening: results of the Singapore Armed Forces Electrocardiogram and Echocardiogram screening protocol

AIMS

Resting 12-lead electrocardiograms (ECGs) have been employed in the pre-participation evaluation of young asymptomatic subjects to detect pre-existing heart diseases. Although the incorporation of routine ECG in pre-participation screening remains controversial, there is increasing evidence that cardiomyopathies and ion channelopathies have ECG changes as the initial manifestation. The causes of sudden cardiac death in young people show significant geographical variation. We aim to determine the prevalence and spectrum of ECG abnormalities in a young male South-East Asian population.

METHODS AND RESULTS

The Singapore Armed Forces Electrocardiogram and Echocardiogram (SAFE) protocol is an ECG-based pre-participation cardiac screening programme modelled after the Italian system. From October 2008 to May 2009, a total of 18 476 young male conscripts (mean age 19.5 years old, range 16-27) underwent mandatory pre-enlistment medical screening at a single medical facility. Subjects with abnormal ECG findings were classified into two groups: Group A had ECG changes that fulfilled a pre-specified checklist to screen for hypertrophic cardiomyopathy and were referred for transthoracic echocardiogram; Group B had other ECG abnormalities [such as Brugada pattern, Wolff-Parkinson-White (WPW) pattern, long QTc] and were referred for secondary screening at a tertiary institution. Of the 18 476 subjects screened, 7.0% (n= 1285) had ECG abnormalities. Of note, 19 (0.10%) had Brugada pattern, 25 (0.14%) had WPW pattern, and 31 (0.17%) had prolonged QT interval on ECG. The prevalence of ECG abnormalities was significantly higher in Chinese than in South Asians (7.2 vs. 5.7%, P= 0.003).

CONCLUSION

The prevalence of ECG abnormalities in a young, South-East Asian male population was 7.0%. There were significant ethnic differences, with ECG abnormalities more prevalent in Chinese than in South Asians (7.2 vs. 5.7%, P= 0.003). The inclusion of universal ECG, in addition to history and physical examination, may increase the sensitivity of a cardiovascular screening programme. Knowledge of the spectrum and prevalence of ECG abnormalities and disease conditions would be pivotal in designing customized screening programmes.