The association between GRACE score at admission for myocardial infarction and the incidence of sudden cardiac arrests in long-term follow-up - the MADDEC study

Background. Sudden cardiac arrest (SCA), often also leading to sudden cardiac death (SCD), is a common complication in coronary artery disease. Despite the effort there is a lack of applicable prediction tools to identify those at high risk. We tested the association between the validated GRACE score and the incidence of SCA after myocardial infarction. Material and methods. A retrospective analysis of 1,985 patients treated for myocardial infarction (MI) between January 1st 2015 and December 31st 2018 and followed until the 31st of December of 2021. The main exposure variable was patients' GRACE score at the point of admission and main outcome variable was incident SCA after hospitalization. Their association was analyzed by subdistribution hazard (SDH) model analysis. The secondary endpoints included SCA in patients with no indication to implantable cardioverter-defibrillator (ICD) device and incident SCD. Results. A total of 1985 patients were treated for MI. Mean GRACE score at baseline was 118.7 (SD 32.0). During a median follow-up time of 5.3 years (IQR 3.8-6.1 years) 78 SCA events and 52 SCDs occurred. In unadjusted analyses one SD increase in GRACE score associated with over 50% higher risk of SCA (SDH 1.55, 95% CI 1.29-1.85, p < 0.0001) and over 40% higher risk for SCD (1.42, 1.12-1.79, p = 0.0033). The associations between SCA and GRACE remained statistically significant even with patients without indication for ICD device (1.57, 1.30-1.90, p < 0.0001) as well as when adjusting with patients LVEF and omitting the age from the GRACE score to better represent the severity of the cardiac event. The association of GRACE and SCD turned statistically insignificant when adjusting with LVEF. Conclusions. GRACE score measured at admission for MI associates with long-term risk for SCA.

Insights into malignant mitral valve degenerative disease from a sudden cardiac death cohort highlighting significant measurement differences from normal

AIMS

Mitral valve prolapse (MVP) is an accepted cause of sudden cardiac death (SCD) in most autopsy series. Diagnosis at autopsy relies upon subjective assessment with no established objective pathological criteria. This study set out to establish objective measurements to help pathologists dealing with SCD.

METHODS

We diagnosed 120 (1.5%) cases of MVP in 8108 cases of SCD. We measured the mitral annulus, anterior and posterior leaflets, rough zone and mitral annular disjunction (MAD) in 27 MVP cases and compared them to 54 age- and sex-matched normal mitral valves.

RESULTS

Age of death was 39 ± 16 years, with 59 females and 61 males. History of mild MV disease was present in 19 (16%). Eleven (9%) died associated with exertion. Left ventricular hypertrophy was present in nine (15%) females and 10 (16%) males. Both MV leaflets showed thickening and ballooning in all individuals. MVP showed highly significantly increased annular circumference, elongation and thickening of both leaflets as well as increased MAD (all P < 0.001). Left ventricular fibrosis was present in 108 (90%), with interstitial fibrosis in the posterolateral wall and papillary muscle in 88 (81%) and coexisting replacement fibrosis in 40 (37%).

CONCLUSION

This is the largest MVP associated with SCD series highlighting a young cohort with equal representation of males and females. There is involvement of both leaflets with significant annular dilatation, elongation and thickening of both leaflets with MAD. Left ventricular fibrosis explains arrhythmia. Our quantitative measurements should serve as a reference for pathologists assessing post-mortem hearts for MVP.

Prognosis and clinical management of asymptomatic family members with RYR2-mediated catecholaminergic polymorphic ventricular tachycardia: a review

Despite its low prevalence, the potential diagnosis of catecholaminergic polymorphic ventricular tachycardia (CPVT) should be at the forefront of a paediatric cardiologists mind in children with syncope during exercise or emotions. Over the years, the number of children with a genetic diagnosis of CPVT due to a (likely) pathogenic RYR2 variant early in life and prior to the onset of symptoms has increased due to cascade screening programmes. Limited guidance for this group of patients is currently available. Therefore, we aimed to summarise currently available literature for asymptomatic patients with a (likely) pathogenic RYR2 variant, particularly the history of CPVT and its genetic architecture, the currently available diagnostic tests and their limitations, and the development of a CPVT phenotype - both electrocardiographically and symptomatic - of affected family members. Their risk of arrhythmic events is presumably low and a phenotype seems to develop in the first two decades of life. Future research should focus on this group in particular, to better understand the development of a phenotype over time, and therefore, to be able to better guide clinical management - including the frequency of diagnostic tests, the timing of the initiation of drug therapy, and lifestyle recommendations.

Arrhythmias and ion channelopathies causing sudden cardiac death in Hispanic/Latino and Indigenous populations

The limited literature and increasing interest in studies on cardiac electrophysiology, explicitly focusing on cardiac ion channelopathies and sudden cardiac death in diverse populations, has prompted a comprehensive examination of existing research. Our review specifically targets Hispanic/Latino and Indigenous populations, which are often underrepresented in healthcare studies. This review encompasses investigations into genetic variants, epidemiology, etiologies, and clinical risk factors associated with arrhythmias in these demographic groups. The review explores the Hispanic paradox, a phenomenon linking healthcare outcomes to socioeconomic factors within Hispanic communities in the United States. Furthermore, it discusses studies exemplifying this observation in the context of arrhythmias and ion channelopathies in Hispanic populations. Current research also sheds light on disparities in overall healthcare quality in Indigenous populations. The available yet limited literature underscores the pressing need for more extensive and comprehensive research on cardiac ion channelopathies in Hispanic/Latino and Indigenous populations. Specifically, additional studies are essential to fully characterize pathogenic genetic variants, identify population-specific risk factors, and address health disparities to enhance the detection, prevention, and management of arrhythmias and sudden cardiac death in these demographic groups.

Biomarker Periodic Repolarization Dynamics Indicates Enhanced Risk for Arrhythmias and Sudden Cardiac Death in Myocardial Infarction in Pigs

BACKGROUND

Periodic repolarization dynamics (PRD) is an electrocardiographic biomarker that captures repolarization instability in the low frequency spectrum and is believed to estimate the sympathetic effect on the ventricular myocardium. High PRD indicates an increased risk for postischemic sudden cardiac death (SCD). However, a direct link between PRD and proarrhythmogenic autonomic remodeling has not yet been shown.

METHODS AND RESULTS

We investigated autonomic remodeling in pigs with myocardial infarction (MI)-related ischemic heart failure induced by balloon occlusion of the left anterior descending artery (n=17) compared with pigs without MI (n=11). Thirty days after MI, pigs demonstrated enhanced sympathetic innervation in the infarct area, border zone, and remote left ventricle paralleled by altered expression of autonomic marker genes/proteins. PRD was enhanced 30 days after MI compared with baseline (pre-MI versus post-MI: 1.75±0.30 deg2 versus 3.29±0.79 deg2, P<0.05) reflecting pronounced autonomic alterations on the level of the ventricular myocardium. Pigs with MI-related ventricular fibrillation and SCD had significantly higher pre-MI PRD than pigs without tachyarrhythmias, suggesting a potential role for PRD as a predictive biomarker for ischemia-related arrhythmias (no ventricular fibrillation versus ventricular fibrillation: 1.50±0.39 deg2 versus 3.18±0.53 deg2 [P<0.05]; no SCD versus SCD: 1.67±0.32 deg2 versus 3.91±0.63 deg2 [P<0.01]).

CONCLUSIONS

We demonstrate that ischemic heart failure leads to significant proarrhythmogenic autonomic remodeling. The concomitant elevation of PRD levels in pigs with ischemic heart failure and pigs with MI-related ventricular fibrillation/SCD suggests PRD as a biomarker for autonomic remodeling and as a potential predictive biomarker for ventricular arrhythmias/survival in the context of MI.

The feasibility of left ventricular strain and strain rate for evaluating patients with risk factors of sudden cardiac death in hypertrophic cardiomyopathy by Feature-tracking Cardiac Magnetic Resonance

Sudden cardiac death (SCD) represents the most severe complication of hypertrophic cardiomyopathy (HCM). However, the relationship between strain, strain rate, and risk factors in SCD risk stratification remains elusive. The study aimed to assess the attenuation of strain and strain rate in HCM by feature-tracking cardiac magnetic resonance (FT-CMR). All strain and strain rates were obtained automatically by FT, with manual adjustment of endocardial and epicardial borders. Strain indicators included left ventricular (LV) global longitudinal (GLS), circumferential (GCS), radial strain (GRS), peak diastolic-longitudinal (PD-LSR), circumferential (PD-CSR), and radial strain rate (PD-RSR). Patients were categorized into high and low-risk groups for SCD based on the 2020 American Heart Association/American College (AHA/ACC) HCM Risk-SCD model. The correlation between strain/strain rate and SCD risk factors was assessed via Spearman correlation analysis. Furthermore, a multivariate logistic regression analysis was conducted to explore the factors that influence SCD risk in HCM patients. A total of 105 HCM patients were analyzed in this study, including 38 patients in the high-risk group, and 67 patients in the low-risk group. Compared to the low-risk group, the high-risk group exhibited significantly worse strain and strain rate (p<0.001). Furthermore, both circumferential and radial strain as well as strain rate exhibited meaningful associations with risk factors for SCD. Additionally, GRS emerged as an independent risk factor for predicting heightened SCD risk in HCM patients (p<0.001). In conclusion, LV strain and strain rate based on FT-CMR can be evaluated for SCD risk and are strongly associated with SCD risk factors.

Ethnicity and Sudden Cardiac Death in Athletes: Insights from a Large United Kingdom Registry

BACKGROUND AND AIMS

The relationship between ethnicity and causes of sudden cardiac death (SCD) in athletes is poorly understood.

OBJECTIVES

To investigate etiology of SCD among different ethnicities in a large cohort of athletes.

METHODS

Between 1994 and November 2022, 7880 cases of SCD were consecutively referred from all over the United Kingdom to our national cardiac pathology centre; 848 (11%) were athletes. All cases underwent detailed autopsy evaluation by expert cardiac pathologists. Clinical information was obtained from referring coroners.

RESULTS

Most of athletes were white (n = 758; 89%). Black and Asian athletes were 51 (6%) and 39 (5%) respectively. A structurally normal heart, indicative of sudden arrhythmic death syndrome (SADS) was the most common autopsy finding (n = 385, 45%), followed by myocardial diseases (n = 275; 32%) cases, atherosclerotic coronary artery disease (CAD) (n = 58, 7%) and coronary artery anomalies (n = 29, 3%). In most of cases, death occurred during exercise (n = 737; 87%) . Arrhythmogenic cardiomyopathy (ACM) was more common in black (n = 13; 25%) than in white (n = 109; 14%) and Asian (n = 3; 8%) athletes (p = 0.03 between black and white athletes; p = 0.04 between black and Asian athletes); in contrast, CAD was more common in Asians (n = 6; 15% vs n = 51; 7% in whites vs 2% n = 1; in blacks, p = 0.02 between Asian and black athletes). Among white athletes, ACM was more common in individuals who died during exercise than in the ones who died at rest (p = 0.005). Such a difference was not observed in Asian and black athletes. In Asian athletes, CAD was the diagnosis at autopsy in 18% of individuals who died during exercise and in none of individuals who died at rest.

CONCLUSIONS

A structurally normal heart at autopsy and myocardial diseases are the most common findings in athletes who died suddenly. While ACM is more common in black athletes, atherosclerotic CAD is more common in Asian athletes, with a strong association with exercise-induced SCD. ACM appears to be a driver of exercise-induced SCD in white athletes, however this is not the case in black and Asian athletes.

Analysis of ventricular arrhythmias and sudden death from prospective, randomized clinical trials of acalabrutinib

This analysis investigated the incidence of sudden deaths (SDs) and non-fatal and fatal ventricular arrhythmias (VAs) in five acalabrutinib clinical trials. In total, 1299 patients received acalabrutinib (exposure, 4568.4 patient-years). Sixteen (1.2%) patients experienced SD or VA (event rate, 0.350/100 patient-years). Non-fatal VAs occurred in 11 (0.8%) patients, nine (0.7%) of whom had premature ventricular contractions only. SD and fatal VAs occurred in five (0.4%) patients (event rate, 0.109/100 patient-years; median time to event: 46.2 months). SDs and VAs with acalabrutinib occurred at low rates, and there are insufficient data to point to an increased risk of SD or VA with acalabrutinib.

SCN5A gene variants and arrhythmic risk in Brugada Syndrome: an updated systematic review and meta-analysis

BACKGROUND

A rare gene variant in SCN5A can be found in approximately 20-25% of patients with Brugada syndrome (BrS).

OBJECTIVE

The aim of this systematic review and meta-analysis is to evaluate: (1) differences in clinical characteristics of BrS patients with and without SCN5A rare variants and (2) the prognostic role of SCN5A for ventricular arrhythmias in BrS.

METHODS

PubMed and Cochrane Central Register of Controlled Trials (CENTRAL) were systematically searched from inception to January 2024 to identify all relevant studies. Studies were analyzed if including patients diagnosed with BrS in whom genetic testing for SCN5A variants was performed and arrhythmic outcomes were reported.

RESULTS

A total of 17 studies with 3568 BrS patients, of whom 3030 patients undergone to genetic testing for SCN5A variants, fulfilled the eligibility criteria and were included. Compared with SCN5A- patients, SCN5A+ BrS patients had more frequently spontaneous type I ECG, history of syncope and documented arrhythmias. Furthermore, higher PQ and QRS intervals in SCN5A+ BrS patients, compared with SCN5A- have been found. The pooled analysis demonstrated a significant association between the presence of SCN5A rare variants in BrS patients and the risk of MAEs, with a pooled OR of 2.14 (95% CI: 1.53; 2.99, I2 = 29%).

CONCLUSION

SCN5A+ BrS patients showed a worse clinical phenotype compared with SCN5A-. The pooled analysis demonstrated a significant association between SCN5A+ mutation status and the risk of MAEs in BrS patients.

Programmed Ventricular Stimulation: Risk Stratification and Guiding Antiarrhythmic Therapies

Electrophysiologic testing with programmed ventricular stimulation (PVS) has been utilized to induce ventricular tachycardia (VT), thereby improving risk stratification for patients with ischemic and nonischemic cardiomyopathies and determining the effectiveness of antiarrhythmic therapies, especially catheter ablation. A variety of procedural aspects can be modified during PVS in order to alter the sensitivity and specificity of the test including the addition of multiple baseline pacing cycle lengths, extrastimuli, and pacing locations. The definition of a positive result is also critically important, which has varied from exclusively sustained monomorphic VT (>30 seconds) to any ventricular arrhythmia regardless of morphology. In this review, we discuss the history of PVS and evaluate its role in sudden cardiac death risk stratification in a variety of patient populations. We propose an approach to future investigations that will capitalize on the unique ability to vary the sensitivity and specificity of this test. We then discuss the application of PVS during and following catheter ablation. The strategies that have been utilized to improve the efficacy of intraprocedural PVS are highlighted during a discussion of the limitations of this probabilistic strategy. The role of noninvasive programmed stimulation is also reviewed in predicting recurrent VT and informing management decisions including repeat ablations, modifications in antiarrhythmic drugs, and implantable cardioverter-defibrillator programming. Based on the available evidence and guidelines, we propose an approach to future investigations that will allow clinicians to optimize the use of PVS for risk stratification and assessment of therapeutic efficacy.

Arrhythmic Manifestations and Outcomes of Definite and Probable Cardiac Sarcoidosis

BACKGROUND

The 2014 HRS consensus statement defines histological (definite) and clinical (probable) diagnostic categories of cardiac sarcoidosis (CS), but few studies have compared their arrhythmic phenotypes and outcomes.

OBJECTIVE

Evaluate the electrophysiologic/arrhythmic phenotype and outcomes of patients with definite and probable CS.

METHODS

We analyzed the arrhythmic/electrophysiologic phenotype in a single-center North American cohort of 388 patients (median age 56 years, 39% female) diagnosed with definite (n=58) or probable (n=330) CS (2000-2022). The primary composite outcome was survival to first ventricular tachycardia/fibrillation (VT/VF) or sudden cardiac death (SCD). Key secondary outcomes were also assessed.

RESULTS

At index evaluation, in situ cardiac implantable electronic devices and antiarrhythmic drug use were more common in definite CS. At median follow-up 3.1 years, the primary outcome occurred in 22 (38%) definite and 127 (38%) probable CS patients (log-rank p=0.55). In multivariable analysis, only higher 18F-FDG SUVmax myocardium:SUVmax blood pool ratio (HR 1.09 [95% CI 1.03, 1.15], p=0.003, per 1 unit increase) was associated with the primary outcome. During follow-up, definite CS patients had higher burden of device-treated VT/VF events (mean 2.86 vs 1.56 per patient-year) and higher rate of progression to heart transplant/left ventricular assist device implantation, but no difference in all-cause mortality compared to probable CS patients.

CONCLUSION

Definite and probable CS patients had similarly high risks of first sustained VT/VF/SCD and all-cause death though definite CS patients had a higher overall arrhythmic burden. Both CS diagnostic groups as defined by the 2014 HRS criteria require an aggressive approach to prevent arrhythmic complications.

Stillbirth Associated With Anomalous Origin and Course of the Left Coronary Artery: A Report of 2 Cases

Coronary artery anomalies and their potential sequelae are not well studied in association with stillbirth. Herein, we report the autopsy findings in two term stillborn fetuses with coronary artery anomalies. Both fetuses showed identical findings consisting of an abnormal origin of the left coronary artery from the right sinus of Valsalva and an interarterial course of the left coronary artery. Histologic vascular and myocardial changes were also present. These coronary artery findings are associated with sudden death in adults and neonates, and therefore, their potential to be a cause and/or contributor to fetal death is suspected.

Distinct Electrogram Features and Ventricular Arrhythmia Induction Modes Between Repolarization and Conduction Heterogeneities

BACKGROUND

Recent clinical studies have indicated the presence of localized electrical abnormalities in idiopathic ventricular fibrillation and J-wave syndrome patients.

OBJECTIVES

This study aims to characterize the specific electrical signatures of localized repolarization and conduction heterogeneities and their respective role in vulnerability to arrhythmias.

METHODS

Optical mapping was performed in porcine right ventricles with local: 1) repolarization shortening; 2) conduction slowing; or 3) structural heterogeneity induced by locally perfusing: 1) pinacidil (20 μmol/L, n = 13); or 2) flecainide (2 μmol/L, n = 13) via an epicardial catheter; or 3) by local epicardial tissue destruction (9 radiofrequency lesions n = 12). Electrograms were recorded (n = 5 in each group) and spontaneous and induced arrhythmias were quantified and optically mapped.

RESULTS

Electrograms were normal in (1) but showed local fragmentation in 40% of preparations in (2) with greater effects observed at high pacing frequencies dependent on the wavefront direction. In (3), the structural substrate alone increased the width and number of peaks in the electrograms, and addition of flecainide induced pronounced fragmentation (≥3 peaks and ≥70 ms) in all cases. Occurrence of spontaneous arrhythmias was significantly increased in (1) and (2) (P < 0.0001 and 0.05, respectively, vs baseline) and were triggered by ectopies. Vulnerability to arrhythmias at high pacing frequencies (≥2 Hz) was the lowest in (1) and greatest in (2).

CONCLUSIONS

Microstructural substrates have the most pronounced impact on electrograms, especially when combined with sodium channel blockers, whereas local action potential duration shortening does not lead to electrogram fragmentation even though it is associated with the highest prevalence of spontaneous arrhythmias.

Cardiovascular screening of elderly athletes

The permanently growing interest in amateur and professional sports activities among young, middle-aged and elderly athletes raises serious concerns about athletes' health, the safety of physical training, and the sports-related risk of sudden cardiac death and other cardiovascular complications during exercise. In recent years there has been an increasing number of cases of sudden cardiac death during physical effort. At present, life expectancy in the most developed countries grows rapidly and the number of people >65 years dramatically increases. Moreover, biological age of the population is lower. Subsequently, relevant increase in the number of elderly athletes involved in various types of sports activities has been reported in many countries. It was also demonstrated that physical activity has strong beneficial effect on cognitive functions, psychomotor performance and thus exercise capacity, which is very important for the elderly people in their everyday routine activities. Nonetheless, it should be remembered that participation in amateur and professional sports activities may be associated with risk of serious cardiovascular events in the elderly athletes often suffering from various civilization diseases. It is also reported that the number of elderly people after interventional cardiology procedures, open heart surgery and cancer treatment (chemotherapy, radiotherapy), who wish to participate in various sports activities, systematically grows. The authors of the paper conduct a literature review on cardiovascular risk assessment in the elderly athletes including the contemporary cardiology diagnostic methods and diagnostic schemes to prevent sudden cardiac death and other cardiovascular events during exercise. The controversies over efficacy of particular diagnostic tools to detect cardiovascular diseases in the elderly athletes and worldwide epidemiologic data concerning risk of sudden cardiac death during physical exercise have been also presented. Here, the authors have derived suggestions for establishment of comprehensive diagnostic schemes to prevent sudden cardiac death during sports activities.

Development of the NOCSAE Standard to Reduce the Risk of Commotio Cordis

BACKGROUND

Commotio cordis, sudden cardiac death (SCD) caused by relatively innocent impact to the chest, is one of the leading causes of SCD in sports. Commercial chest protectors have not been demonstrated to mitigate the risk of these SCDs.

METHODS

To develop a standard to assess chest protectors, 4 phases occurred. A physiological commotio cordis model was utilized to assess variables that predicted for SCD. Next, a surrogate model was developed based on data from the physiological model, and the attenuation in risk was assessed. In the third phase, this model was calibrated and validated. Finally, National Operating Committee on Standards for Athletic Equipment adopted the standard and had an open review process with revision of the standard over 3 years.

RESULTS

Of all variables, impact force was the most robust at predicting SCD. Chest wall protectors which could reduce the force of impact to under thresholds were predicted to reduce the risk of SCD. The correlation between the experimental model and the mechanical surrogate ranged from 0.783 with a lacrosse ball at 30 mph to 0.898 with a baseball at 50 mph. The standard was licensed to National Operating Committee on Standards for Athletic Equipment which initially adopted the standard in January 2018, and finalized in July 2021.

CONCLUSIONS

An effective mechanical surrogate based on physiological data from a well-established model of commotio cordis predicts the reduction in SCD with chest protectors. A greater reduction in force provides a great degree of protection from commotio cordis. This new National Operating Committee on Standards for Athletic Equipment standard for chest protectors should result in a significant reduction in the risk of commotio cordis on the playing field.

Determinants of Ventricular Arrhythmias in Mitral Valve Prolapse

BACKGROUND

Mitral valve prolapse (MVP) may be associated with ventricular arrhythmias (VA) even in the absence of significant valvular regurgitation. Curling, mitral annulus disjunction (MAD) and myocardial fibrosis (late gadolinium enhancement [LGE]) may account for arrhythmogenesis.

OBJECTIVES

This study investigated the determinants of VA in patients with MVP without significant regurgitation.

METHODS

This study included 108 patients with MVP (66 female; median age: 48 years) without valve regurgitation. All patients underwent 12-lead electrocardiography, 12-lead 24-hour electrocardiographic Holter monitoring, exercise stress test, and cardiac magnetic resonance. Patients were divided into 2 groups (arrhythmic and no-arrhythmic MVP), according to the presence of VA with a right bundle branch block pattern.

RESULTS

The 62 patients (57%) with arrhythmic MVP showed: 1) higher MAD (median length: 6.0 vs 3.2 mm; P = 0.017); 2) higher prevalence of curling (79% vs 52%; P = 0.012); and 3) higher prevalence of left ventricular LGE (79% vs 52%; P = 0.012). Mediation analysis showed that curling had both a direct (P = 0.03) and indirect effect mediated by LGE (P = 0.04) on VA, whereas the association between MAD and VA was completely mediated by LGE. Patients with severe VA showed more pronounced morphofunctional alterations, in terms of MAD (7.0 vs 4.6 mm; P = 0.004) and presence and severity of curling (respectively, 91% vs 64%; P = 0.010; and 4 vs 3 mm; P = 0.004), compared to those without severe VA.

CONCLUSIONS

In patients with MVP the occurrence of VA with right bundle branch block morphology is the expression of more severe morphologic, mechanical, and tissue alterations. Curling has both a direct and an indirect effect on VA.

Implementing a New Algorithm for Reinterpretation of Ambiguous Variants in Genetic Dilated Cardiomyopathy

Dilated cardiomyopathy is a heterogeneous entity that leads to heart failure and malignant arrhythmias. Nearly 50% of cases are inherited; therefore, genetic analysis is crucial to unravel the cause and for the early identification of carriers at risk. A large number of variants remain classified as ambiguous, impeding an actionable clinical translation. Our goal was to perform a comprehensive update of variants previously classified with an ambiguous role, applying a new algorithm of already available tools. In a cohort of 65 cases diagnosed with dilated cardiomyopathy, a total of 125 genetic variants were classified as ambiguous. Our reanalysis resulted in the reclassification of 12% of variants from an unknown to likely benign or likely pathogenic role, due to improved population frequencies. For all the remaining ambiguous variants, we used our algorithm; 60.9% showed a potential but not confirmed deleterious role, and 24.5% showed a potential benign role. Periodically updating the population frequencies is a cheap and fast action, making it possible to clarify the role of ambiguous variants. Here, we perform a comprehensive reanalysis to help to clarify the role of most of ambiguous variants. Our specific algorithms facilitate genetic interpretation in dilated cardiomyopathy.

Arrhythmogenic Left Ventricular Cardiomyopathy: From Diagnosis to Risk Management

PURPOSE OF REVIEW

Left ventricular arrhythmogenic cardiomyopathy (ALVC) is a rare and poorly characterized cardiomyopathy that has recently been reclassified in the group of non-dilated left ventricular cardiomyopathies. This review aims to summarize the background, diagnosis, and sudden cardiac death risk in patients presenting this cardiomyopathy.

RECENT FINDINGS

Although there is currently a lack of data on this condition, arrhythmogenic left ventricular dysplasia can be considered a specific disease of the left ventricle (LV). We have collected the latest evidence about the management and the risks associated with this cardiomyopathy.

SUMMARY

Left ventricular arrhythmogenic cardiomyopathy is still poorly characterized. ALVC is characterized by fibrofatty replacement in the left ventricular myocardium, with variable phenotypic expression. Diagnosis is based on a multiparametric approach, including cardiac magnetic resonance (CMR) and genetic testing, and is important for sudden cardiac death (SCD) risk stratification and management. Recent guidelines have improved the management of left ventricular arrhythmogenic cardiomyopathy. Further studies are necessary to improve knowledge of this cardiomyopathy.

Risk Prediction for Sudden Cardiac Death in the General Population: A Systematic Review and Meta-Analysis

Objective: Identification of SCD risk is important in the general population from a public health perspective. The objective is to summarize and appraise the available prediction models for the risk of SCD among the general population. Methods: Data were obtained searching six electronic databases and reporting prediction models of SCD risk in the general population. Studies with duplicate cohorts and missing information were excluded from the meta-analysis. Results: Out of 8,407 studies identified, fifteen studies were included in the systematic review, while five studies were included in the meta-analysis. The Cox proportional hazards model was used in thirteen studies (96.67%). Study locations were limited to Europe and the United States. Our pooled meta-analyses included four predictors: diabetes mellitus (ES = 2.69, 95%CI: 1.93, 3.76), QRS duration (ES = 1.16, 95%CI: 1.06, 1.26), spatial QRS-T angle (ES = 1.46, 95%CI: 1.27, 1.69) and factional shortening (ES = 1.37, 95%CI: 1.15, 1.64). Conclusion: Risk prediction model may be useful as an adjunct for risk stratification strategies for SCD in the general population. Further studies among people except for white participants and more accessible factors are necessary to explore.

Ankle-Brachial Index and Risk of Sudden Cardiac Death in the Community: The ARIC Study

BACKGROUND

Sudden cardiac death (SCD) is a significant global public health problem accounting for 15% to 20% of all deaths. A great majority of SCD is associated with coronary heart disease, which may first be detected at autopsy. The ankle-brachial index (ABI) is a simple, noninvasive measure of subclinical atherosclerosis. The purpose of this study was to examine the relationship between ABI and SCD in a middle-aged biracial general population.

METHODS AND RESULTS

Participants of the ARIC (Atherosclerosis Risk in Communities) study with an ABI measurement between 1987 and 1989 were included. ABI was categorized as low (≤0.90), borderline (0.90-1.00), normal (1.00-1.40), and noncompressible (>1.40). SCD was defined as a sudden pulseless condition presumed to be caused by a ventricular tachyarrhythmia in a previously stable individual and was adjudicated by a committee of cardiac electrophysiologists, cardiologists, and internists. Cox proportional hazards models were used to evaluate the associations between baseline ABI and incident SCD. Of the 15 081 participants followed for a median of 23.5 years, 556 (3.7%) developed SCD (1.96 cases per 1000 person-years). Low and borderline ABIs were associated with an increased risk of SCD (demographically adjusted hazard ratios [HRs], 2.27 [95% CI, 1.64-3.14] and 1.52 [95% CI, 1.17-1.96], respectively) compared with normal ABI. The association between low ABI and SCD remained significant after adjustment for traditional cardiovascular risk factors (HR, 1.63 [95% CI, 1.15-2.32]).

CONCLUSIONS

Low ABI is independently associated with an increased risk of SCD in a middle-aged biracial general population. ABI could be incorporated into future SCD risk prediction models.

Relationship of Mild to Moderate Impairment of Left Ventricular Ejection Fraction With Fatal Ventricular Arrhythmic Events in Cardiac Sarcoidosis

BACKGROUND

Current guidelines recommend placing an implantable cardiac defibrillator for patients with cardiac sarcoidosis and a severely impaired left ventricular ejection fraction (LVEF) of ≤35%. In this study, we determined the association between mild or moderate LVEF impairment and fatal ventricular arrhythmic event (FVAE).

METHODS AND RESULTS

We retrospectively analyzed 401 patients with cardiac sarcoidosis without sustained ventricular arrhythmia at diagnosis. The primary end point was an FVAE, defined as the combined endpoint of documented ventricular tachycardia or ventricular fibrillation and sudden cardiac death. Two cutoff points for LVEF were used: a sex-specific lower threshold of normal range of LVEF (52% for men and 54% for women) and an LVEF of 35%, which is used in the current guidelines. During a median follow-up of 3.2 years, 58 FVAEs were observed, and the 5- and 10-year estimated incidences of FVAEs were 16.8% and 23.0%, respectively. All patients were classified into 3 groups according to LVEF: impaired LVEF group, mild to moderate impairment of LVEF group, and maintained LVEF group. Multivariable competing risk analysis showed that both the impaired LVEF group (hazard ratio [HR], 3.24 [95% CI, 1.49-7.04]) and the mild to moderate impairment of LVEF group (HR, 2.16 [95% CI, 1.04-4.46]) were associated with a higher incidence of FVAEs than the maintained LVEF group after adjustment for covariates.

CONCLUSIONS

Patients with cardiac sarcoidosis are at a high risk of FVAEs, regardless of documented ventricular arrhythmia at the time of diagnosis. In patients with cardiac sarcoidosis, mild to moderate impairment of LVEF is associated with FVAEs.

Case Report: Comprehensive evaluation of ECG phenotypes and genotypes in a family with Brugada syndrome carrying SCN5A-R376H

Background

Brugada syndrome (BrS) is a channelopathy that can lead to sudden cardiac death in the absence of structural heart disease. Patients with BrS can be asymptomatic or present with symptoms secondary to polymorphic ventricular tachycardia or ventricular fibrillation. Even though BrS can exhibit autosomal dominant inheritance, it is not easy to identify the phenotype and genotype in a family thoroughly.

Case

We report the case of a 20-year-old man with variants in SCN5A and RyR2 genes who was resuscitated from sudden cardiac death during sleep due to a ventricular fibrillation. The patient did not have underlying diseases. The routine laboratory results, imaging study, coronary angiogram, and echocardiogram (ECG) were normal. A type 1 BrS pattern was identified in one resting ECG. Furthermore, prominent J wave accentuation with PR interval prolongation was identified during therapeutic hypothermia. Therefore, we were easily able to diagnose BrS. For secondary prevention, the patient underwent implantable cardioverter defibrillator implantation. Before discharge, a genetic study was performed using next-generation sequencing. Genotyping was performed in the first-degree relatives, and ECG evaluations of almost all maternal and paternal family members were conducted. The proband and his mother showed SCN5A-R376H and RyR2-D4038Y variants. However, his mother did not show the BrS phenotype on an ECG. One maternal aunt and uncle showed BrS phenotypes.

Conclusion

Genetics alone cannotdiagnose BrS. However, genetics could supply evidence or direction for evaluating ECG phenotypes in family groups. This case report shows how family evaluation using ECGs along with a genetic study can be used in BrS diagnosis.

Liver X Receptor Agonist 4β-Hydroxycholesterol as a Prognostic Factor in Coronary Artery Disease

BACKGROUND

Regardless of progress in treatment of coronary artery disease (CAD), there is still a significant residual risk of death in patients with CAD, highlighting the need for additional risk stratification markers. Our previous study provided evidence for a novel blood pressure-regulating mechanism involving 4β-hydroxycholesterol (4βHC), an agonist for liver X receptors, as a hypotensive factor. The aim was to determine the role of 4βHC as a prognostic factor in CAD.

METHODS AND RESULTS

The ARTEMIS (Innovation to Reduce Cardiovascular Complications of Diabetes at the Intersection) cohort consists of 1946 patients with CAD. Men and women were analyzed separately in quartiles according to plasma 4βHC. Basic characteristics, medications, ECG, and echocardiography parameters as well as mortality rate were analyzed. At baseline, subjects with a beneficial cardiovascular profile, as assessed with traditional markers such as body mass index, exercise capacity, prevalence of diabetes, and use of antihypertensives, had the highest plasma 4βHC concentrations. However, in men, high plasma 4βHC was associated with all-cause death, cardiac death, and especially sudden cardiac death (SCD) in a median follow-up of 8.8 years. Univariate and comprehensively adjusted hazard ratios for SCD in the highest quartile were 3.76 (95% CI, 1.6-8.7; P=0.002) and 4.18 (95% CI, 1.5-11.4; P=0.005), respectively. In contrast, the association of cardiac death and SCD in women showed the lowest risk in the highest 4βHC quartile.

CONCLUSIONS

High plasma 4βHC concentration was associated with death and especially SCD in men, while an inverse association was detected in women. Our results suggest 4βHC as a novel sex-specific risk marker of cardiac death and especially SCD in chronic CAD.

REGISTRATION INFORMATION

clinicaltrials.gov. Identifier NCT01426685.

Cardiomyopathy with an LMNA Genetic Variant Affecting Three Consecutive Generations: A Case Series

We report the case of a family afflicted with cardiac laminopathy who showed atrial fibrillation (AF) and complete atrioventricular block across three generations. Implantable cardioverter defibrillators (ICDs) implantation, or cardiac resynchronization therapy (CRT) were delivered to the three patients (proband; 61 years old, proband's mother: 84 years old, and proband's daughter; 38 years old) to prevent sudden cardiac death or suppress heart failure progression. A novel frameshift mutation (LMNA Exon 9: c.1550dupA;p. N518Efs*34) was found in all three cases through genetic testing, and this mutation may potentially result in the relatively late appearance of a phenotype of left ventricular systolic dysfunction.

Role of low-density lipoprotein electronegativity and sexual dimorphism in contributing early ventricular tachyarrhythmias following ST-elevation myocardial infarction

Background

Early ventricular tachycardia/fibrillation (VT/VF) in patients with ST-elevation myocardial infarction (STEMI) has higher morbidity and mortality. This study examines gender-differentiated risk factors and underlying mechanisms for early onset VT/VF in STEMI.

Methods

We analyzed data from 2,964 consecutive STEMI patients between January 1, 2008 and December 31, 2021. Early VT/VF was defined as occurrence of spontaneous VT/VF of ≥30 s or requirement of immediate cardioversion/defibrillation within the first 48 h after symptoms. An ex vivo ischemic-reperfusion experiments were conducted in 8-week-old ApoE-/- mice fed a high-fat diet to explore the underlying mechanisms of early VT/VF.

Results

In 255 of out 2,964 STEMI patients who experienced early VT/VF, the age was younger (58.6 ± 13.8 vs. 61.0 ± 13.0 years old, P = 0.008) with a male predominance. The plasma levels of L5, the most electronegative subclass of low-density lipoprotein, was higher in early VT/VF patients compared to those without early VT/VF (n = 21, L5: 14.1 ± 22.6% vs. n = 46, L5: 4.3 ± 9.9%, P = 0.016). In the experimental setup, all male mice (n = 4) developed VT/VF post sham operation, whereas no such incidence was observed in the female mice (n = 3). Significantly, male mice exhibited considerably slower cardiac conduction velocity as compared to their female counterparts in whole heart preparations (25.01 ± 0.93 cm/s vs.42.32 ± 5.70 cm/s, P < 0.001), despite analogous action potential durations. Furthermore, isolated ventricular myocytes from male mice showed a distinctly lower sodium current density (-29.20 ± 3.04 pA/pF, n = 6) in comparison to female mice (-114.05 ± 6.41 pA/pF, n = 6, P < 0.001). This decreased sodium current density was paralleled by a reduced membrane expression of Nav1.5 protein (0.38 ± 0.06 vs. 0.89 ± 0.09 A.U., P < 0.001) and increased cytosolic Nav1.5 levels (0.59 ± 0.06 vs. 0.29 ± 0.04 A.U., P = 0.001) in male mice. Furthermore, it was observed that the overall expressions of sorting nexin 27 (SNX27) and vacuolar protein sorting 26 (VPS26) were significantly diminished in male mice as compared to female littermates (0.91 ± 0.15 vs. 1.70 ± 0.28, P = 0.02 and 0.74 ± 0.09 vs. 1.57 ± 0.13, P < 0.01, respectively).

Conclusions

Our findings reveal that male STEMI patients with early VT/VF are associated with elevated L5 levels. The gender-based discrepancy in early VT/VF predisposition might be due to compromised sodium channel trafficking, possibly linked with increased LDL electronegativity.

Cardiovascular Rehabilitation With a WCD-Data From the CR3 Study (Cardiac Rehab Retrospective Review)

PURPOSE

Patients at risk for sudden cardiac death may temporarily need a wearable cardioverter-defibrillator (WCD). Exercise-based cardiac rehabilitation (CR) has a class I recommendation in patients with cardiac disease. The aim of this study was to evaluate the safety and feasibility of undergoing CR with a WCD.

METHODS

We performed a retrospective analysis of all patients with a WCD who completed a CR in Austria (2010-2020).

RESULTS

Patients (n = 55, 60 ± 11 yr, 16% female) with a median baseline left ventricular ejection fraction (LVEF) of 36 (30, 41)% at the start of CR showed a daily WCD wearing duration of 23.4 (22, 24) hr. There were 2848 (8 [1, 26]/patient) automatic alarms and 340 (3 [1, 7]/patient) manual alarms generated. No shocks were delivered by the WCD during the CR period. One patient had recurrent hemodynamically tolerated ventricular tachycardias that were controlled with antiarrhythmic drugs.No severe WCD-associated adverse events occurred during the CR stay of a median 28 (28, 28) d. The fabric garment and the device setting needed to be adjusted in two patients to diminish inappropriate automatic alarms. Left ventricular ejection fraction after CR increased significantly to 42 (30, 44)% ( P < .001). Wearable cardioverter-defibrillator therapy was stopped due to LVEF restitution in 53% of patients. In 36% of patients an implantable cardioverter-defibrillator was implanted, 6% had LVEF improvement after coronary revascularization, one patient received a heart transplantation (2%), two patients discontinued WCD treatment at their own request (4%).

CONCLUSION

Completing CR is feasible and safe for WCD patients and may contribute positively to the restitution of cardiac function.

Risk of Sudden Cardiac Death in Patients Undergoing Cancer Treatment

The risk of sudden cardiac death (SCD) in patients with cancer receiving cancer therapies is not well defined. In this study we aimed to (1) evaluate the risk of SCD during the first 6 months of cancer treatment and (2) identify risk factors (RFs) for SCD in patients who underwent active cancer treatment. The study population comprised 8,356 patients who received any cancer treatment at the University of Rochester Medical Center from 2011 to 2020. The primary end point was the occurrence of SCD within 6 months of cancer treatment. SCD was defined by using the modified Hinkle-Thaler classification. The mean age at the time of cancer treatment was 64 ± 14 years and 49% were women. All-cause mortality occurred in 834 patients (10%), of whom 51 (6%) were identified as SCD. The cumulative probability of SCD at 6 months was 0.6%. Age <74 years (0.042), history of congestive heart failure (0.058) and lung cancer (0.004) were identified as independent RFs for SCD in the multivariate Cox regression models. The cumulative probability of SCD at 6 months from cancer treatment initiation was significantly higher in patients with ≥2 RFs (1.6%) than in patients with 0 or 1 RF (0.5%) (log-rank p <0.001). In conclusion, our findings suggest that active cancer treatment is associated with SCD risk that is more pronounced in younger patients (< 74 years), patients with cancer and a history of heart failure, and those who underwent treatment for lung cancer. Future studies should address appropriate modalities for prevention and protection in this high-risk population.

Novel NKX2.5 variant associated with congenital heart disease and increased risk of malignant arrhythmia and sudden cardiac death

INTRODUCTION

The NKX2.5 gene is an important cardiac developmental transcription factor, and variants in this gene are most commonly associated with CHD. However, there is an increased need to recognise associations with conduction disease and potentially dangerous ventricular arrhythmias. There is an increased risk of arrhythmia and sudden cardiac death in patients with NKX2.5 variants, an association with relatively less attention in the literature.

METHODS

We created a family pedigree and reconstructed familial relationships involving numerous relatives with CHD, conduction disease, and ventricular non-compaction following the sudden death of one family member. Two informative but distantly related family members had genetic testing to determine the cause of arrhythmias via arrhythmia/cardiomyopathy gene testing, and we identified obligate genetic-positive relatives based on family relationships and Mendelian inheritance pattern.

RESULTS

We identified a novel pathogenic variant in the NKX2.5 gene (c.437C > A; p. Ser146*), and segregation analysis allowed us to link family cardiac phenotypes including CHD, conduction disease, left ventricular non-compaction, and ventricular arrhythmias/sudden cardiac death.

CONCLUSIONS

We report a novel NKX2.5 gene variant linking a spectrum of familial heart disease, and we also encourage recognition of the association between NKX2.5 gene and potentially dangerous ventricular arrhythmias, which will inform clinical risk stratification, screening, and management.

Anti-Arrhythmic Effects of Heart Failure Guideline-Directed Medical Therapy and Their Role in the Prevention of Sudden Cardiac Death: From Beta-Blockers to Sodium-Glucose Cotransporter 2 Inhibitors and Beyond

Sudden cardiac death (SCD) accounts for a substantial proportion of mortality in heart failure with reduced ejection fraction (HFrEF), frequently triggered by ventricular arrhythmias (VA). This review aims to analyze the pathophysiological mechanisms underlying VA and SCD in HFrEF and evaluate the effectiveness of guideline-directed medical therapy (GDMT) in reducing SCD. Beta-blockers, angiotensin receptor-neprilysin inhibitors, and mineralocorticoid receptor antagonists have shown significant efficacy in reducing SCD risk. While angiotensin-converting enzyme inhibitors and angiotensin receptor blockers exert beneficial impacts on the renin-angiotensin-aldosterone system, their direct role in SCD prevention remains less clear. Emerging treatments like sodium-glucose cotransporter 2 inhibitors show promise but necessitate further research for conclusive evidence. The favorable outcomes of those molecules on VA are notably attributable to sympathetic nervous system modulation, structural remodeling attenuation, and ion channel stabilization. A multidimensional pharmacological approach targeting those pathophysiological mechanisms offers a complete and synergy approach to reducing SCD risk, thereby highlighting the importance of optimizing GDMT for HFrEF. The current landscape of HFrEF pharmacotherapy is evolving, with ongoing research needed to clarify the full extent of the anti-arrhythmic benefits offered by both existing and new treatments.

Pathological Characteristics and Classification of Unstable Coronary Atherosclerotic Plaques

Important forensic diagnostic indicators of sudden death in coronary atherosclerotic heart disease, such as acute or chronic myocardial ischemic changes, sometimes make it difficult to locate the ischemic site due to the short death process, the lack of tissue reaction time. In some cases, the deceased died of sudden death on the first-episode, resulting in difficulty for medical examiners to make an accurate diagnosis. However, clinical studies on coronary instability plaque revealed the key role of coronary spasm and thrombosis caused by their lesions in sudden coronary death process. This paper mainly summarizes the pathological characteristics of unstable coronary plaque based on clinical medical research, including plaque rupture, plaque erosion and calcified nodules, as well as the influencing factors leading to plaque instability, and briefly describes the research progress and technique of the atherosclerotic plaques, in order to improve the study on the mechanism of sudden coronary death and improve the accuracy of the forensic diagnosis of sudden coronary death by diagnosing different pathologic states of coronary atherosclerotic plaques.

Mortality Benefit Among Primary Prevention Implantable Cardioverter Defibrillator Recipients on Contemporary Heart Failure Treatment

BACKGROUND

Past clinical trials have shown the benefit of implantable cardioverter-defibrillators (ICDs) for reducing sudden cardiac death in at-risk patients. However, heart failure management and ICD technology have changed since these trials were first published. An updated assessment of ICD mortality benefit is needed.

OBJECTIVES

The purpose of this study was to compare mortality rates between patients with a primary prevention (PP) indication for an ICD who did or did not receive an ICD using a contemporary, real-world data set.

METHODS

Data was obtained from a large electronic health record data set covering patients in the United States from 2012 through 2020 who had a PP indication for an ICD and survived at least 1-year postindication.

RESULTS

A total of 25,296 patients were identified as having a PP indication for ICD implantation, of which 2,118 (8.4%) were treated with an ICD within a year. Treated patients were younger than nontreated patients (63.4 years vs 66.1 years) with a smaller proportion of women (25.0% vs 36.7%). After 4-to-1 propensity matching, treated patients had similar clinical characteristics to nontreated patients. A Cox proportional hazard model estimated a 24.3% lower risk of all-cause mortality in patients when treated vs not treated with an ICD (HR: 0.757; CI: 0.678-0.835; P <0.001). There was no detectable difference in ICD benefit between patients with ischemic and nonischemic heart disease (P = 0.50).

CONCLUSIONS

ICD treatment of patients with a PP indication is associated with improved mortality even in the context of evolving adjunctive HF treatment, consistent with earlier landmark trials.

Ventricular Arrhythmias and Hemodynamic Collapse During Acute Coronary Syndrome- Increased Risk for Sudden Cardiac Death?

AIM

In acute phase of acute coronary syndrome (ACS), ventricular tachycardia (VT) and/or ventricular fibrillation (VF) leading to resuscitation are not considered to be associated with increased long-term sudden cardiac death (SCD) because the cause - acute ischemia - is believed to be reversible.Aim of this study was to investigate whether ventricular arrhythmias leading to sudden cardiac arrest during ACS associate with the risk of incident SCD in patients with normal or mildly impaired left ventricular ejection fraction (LVEF).

METHODS

This study is based on a retrospective analysis of all 8,062 consecutive ACS patients undergoing coronary angiography with baseline LVEF ≥40% between 2007-2018 (follow-up until December 31st, 2021). The primary outcome was SCD equivalent life-threatening ventricular arrhythmias (LTVA) composing of true SCDs, aborted SCDs by successful resuscitation or appropriate ICD therapy. The risk of sudden LTVA was estimated with multivariate subdistribution hazard model using other deaths as competing events.

RESULTS

Two-hundred and thirteen (n=211, 2.6%) patients suffered acute phase VF/VT leading to resuscitation and survived to discharge and most happened before angiography (80.6%, N=170) and were VF (92.9%, N=196). During a median follow-up of 7.6 years, 3.9% (N=316) of all the patients had LTVA (10.0% in VF/VT group vs 3.8% in other patients). VF/VTs during ACS associated with an increased risk for future SCD (HR 3.07; 95% CI 1.94-4.85, p<0.001). Most LTVAs occurred in patients without ICDs.

CONCLUSIONS

VF/VT in ACS associates with remarkably high long-term risk for SCD in patients with LVEF ≥40%.

Arrhythmic mitral valve prolapse: a practical approach for asymptomatic patients

Mitral valve prolapse (MVP) is usually regarded as a benign condition though the proportion of patients with a life-threatening arrhythmic MVP form remains undefined. Recently, an experts' consensus statement on arrhythmic MVP has proposed approaches for risk stratification across the spectrum of clinical manifestation. However, sudden cardiac death may be the first presentation, making clinicians focused to early unmasking this subset of asymptomatic patients. Growing evidence on the role of cardiac imaging in the in-deep stratification pathway has emerged in the last decade. Pathology findings have suggested the fibrosis of papillary muscles and inferobasal left ventricular wall as the malignant hallmark. Cardiac magnetic resonance, while of limited availability, allows the identification of this arrhythmogenic substrate. Therefore, speckle-tracking echocardiography may be a gateway to prompt referring patients to further advanced imaging investigation. Our review aims to summarize the phenotypic features linked to the arrhythmic risk and to propose an image-based algorithm intended to help stratifying asymptomatic MVP patients.

Arrhythmogenic Right Ventricular Cardiomyopathy Post-Mortem Assessment: A Systematic Review

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic disorder characterized by the progressive fibro-fatty replacement of the right ventricular myocardium, leading to myocardial atrophy. Although the structural changes usually affect the right ventricle, the pathology may also manifest with either isolated left ventricular myocardium or biventricular involvement. As ARVC shows an autosomal dominant pattern of inheritance with variable penetrance, the clinical presentation of the disease is highly heterogeneous, with different degrees of severity and patterns of myocardial involvement even in patients of the same familiar group with the same gene mutation: the pathology spectrum ranges from the absence of symptoms to sudden cardiac death (SCD) sustained by ventricular arrhythmias, which may, in some cases, be the first manifestation of an otherwise silent pathology. An evidence-based systematic review of the literature was conducted to evaluate the state of the art of the diagnostic techniques for the correct post-mortem identification of ARVC. The research was performed using the electronic databases PubMed and Scopus. A methodological approach to reach a correct post-mortem diagnosis of ARVC was described, analyzing the main post-mortem peculiar macroscopic, microscopic and radiological alterations. In addition, the importance of performing post-mortem genetic tests has been underlined, which may lead to the correct identification and characterization of the disease, especially in those ARVC forms where anatomopathological investigation does not show evident morphostructural damage. Furthermore, the usefulness of genetic testing is not exclusively limited to the correct diagnosis of the pathology, but is essential for promoting targeted screening programs to the deceased's family members. Nowadays, the post-mortem diagnosis of ARVC performed by forensic pathologist remains very challenging: therefore, the identification of a clear methodological approach may lead to both a reduction in under-diagnoses and to the improvement of knowledge on the disease.

Do Implantable Cardioverter-Defibrillators Prevent Sudden Cardiac Death in End-Stage Renal Disease Patients on Dialysis?

Chronic kidney disease patients appear to be predisposed to heart rhythm disorders, including atrial fibrillation/atrial flutter, ventricular arrhythmias, and supraventricular tachycardias, which increase the risk of sudden cardiac death. The pathophysiological factors underlying arrhythmia and sudden cardiac death in patients with end-stage renal disease are unique and include timing and frequency of dialysis and dialysate composition, vulnerable myocardium, and acute proarrhythmic factors triggering asystole. The high incidence of sudden cardiac deaths suggests that this population could benefit from implantable cardioverter-defibrillator therapy. The introduction of implantable cardioverter-defibrillators significantly decreased the rate of all-cause mortality; however, the benefits of this therapy among patients with chronic kidney disease remain controversial since the studies provide conflicting results. Electrolyte imbalances in haemodialysis patients may result in ineffective shock therapy or the appearance of non-shockable underlying arrhythmic sudden cardiac death. Moreover, the implantation of such devices is associated with a risk of infections and central venous stenosis. Therefore, in the population of patients with heart failure and severe renal impairment, periprocedural risk and life expectancy must be considered when deciding on potential device implantation. Harmonised management of rhythm disorders and renal disease can potentially minimise risks and improve patients' outcomes and prognosis.

Utility of Intracoronary Acetylcholine Provocation Testing in Inducing Atrial Fibrillation with Preexcitation Followed by Ventricular Fibrillation in a Patient with Wolff-Parkinson-White Syndrome: A Case Report

A 20-year-old man was resuscitated after ventricular fibrillation (VF). Electrocardiography revealed Wolff-Parkinson-White (WPW) syndrome. Intracoronary acetylcholine provocation testing was performed to induce VF secondary to the coronary vasospasm. The administration of acetylcholine to the coronary artery induced atrial fibrillation (AF) with pre-excitation, followed by VF without coronary vasospasm. Electrophysiological studies revealed an accessory pathway managed by catheter ablation. Subsequent intracoronary acetylcholine provocation testing (ACH test) induced the occurrence of AF without preexcitation. To our knowledge, this case report is the first to demonstrate the utility of the ACH test in confirming WPW syndrome as a cause of VF.

The Role of Carotid-Femoral Pulse Wave Velocity in a Metabolic Syndrome Patient with Sudden Cardiac Arrest: A Case Report

INTRODUCTION

Carotid-femoral pulse wave velocity reflecting aortic stiffness could be used as an independent predictor of future cardiovascular events for an individual with metabolic syndrome. However, the routine use of carotid-femoral pulse wave velocity is suboptimized in clinical practice. We report a case of metabolic syndrome with increased carotid-femoral pulse wave velocity and subsequently developed myocardial infarction and sudden cardiac arrest.

CASE PRESENTATION

A Polish man of an age between 40 and 50 years previously diagnosed with metabolic syndrome with essential hypertension, obesity, dyslipidaemia, and impaired glucose level. He developed myocardial infarction, ventricular fibrillation, and was successfully resuscitated with defibrillation. The patient showed high-normal traditional cardiovascular risk factors but an increased carotid-femoral pulse wave velocity. The increased carotid-femoral pulse wave velocity is associated with an increased arterial stiffness, which altered the myocardial perfusion and induced the anterior-lateral ST elevation myocardial infarction. The patient actively participated and completed the phase II cardiac rehabilitation programme. To the best of our knowledge, there have been few studies on carotid-femoral pulse wave velocity screening for patients with metabolic syndrome. Pulse wave velocity screening by a physician appears to be helpful in identifying the potential high-risk population with borderline traditional cardiovascular risk factors.

CONCLUSION

This trajectory highlights the clinical relevance of using carotid-femoral pulse wave velocity as an adjunct marker to assess the risk of cardiovascular event for patients with metabolic syndrome.

Comprehensive Cardiovascular Management of Myotonic Dystrophy Type 1 Patients: A Report from the Italian Neuro-Cardiology Network

Myotonic dystrophy is a hereditary disorder with systemic involvement. The Italian Neuro-Cardiology Network-"Rete delle Neurocardiologie" (INCN-RNC) is a unique collaborative experience involving neurology units combined with cardio-arrhythmology units. The INCN facilitates the creation of integrated neuro-cardiac teams in Neuromuscular Disease Centers for the management of cardiovascular involvement in the treatment of myotonic dystrophy type 1 (MD1).

Cardiac-Specific Deletion of Scn8a Mitigates Dravet Syndrome-Associated Sudden Death in Adults

BACKGROUND

Sudden unexpected death in epilepsy (SUDEP) is a fatal complication experienced by otherwise healthy epilepsy patients. Dravet syndrome (DS) is an inherited epileptic disorder resulting from loss of function of the voltage-gated sodium channel, NaV 1.1, and is associated with particularly high SUDEP risk. Evidence is mounting that NaVs abundant in the brain also occur in the heart, suggesting that the very molecular mechanisms underlying epilepsy could also precipitate cardiac arrhythmias and sudden death. Despite marked reduction of NaV 1.1 functional expression in DS, pathogenic late sodium current (INa,L) is paradoxically increased in DS hearts. However, the mechanisms by which DS directly impacts the heart to promote sudden death remain unclear.

OBJECTIVES

In this study the authors sought to provide evidence implicating remodeling of Na+ - and Ca2+ -handling machinery, including NaV 1.6 and Na+/Ca2+exchanger (NCX) within transverse (T)-tubules in DS-associated arrhythmias.

METHODS

The authors undertook scanning ion conductance microscopy (SICM)-guided patch clamp, super-resolution microscopy, confocal Ca2+ imaging, and in vivo electrocardiography studies in Scn1a haploinsufficient murine model of DS.

RESULTS

DS promotes INa,L in T-tubular nanodomains, but not in other subcellular regions. Consistent with increased NaV activity in these regions, super-resolution microscopy revealed increased NaV 1.6 density near Ca2+release channels, the ryanodine receptors (RyR2) and NCX in DS relative to WT hearts. The resulting INa,L in these regions promoted aberrant Ca2+ release, leading to ventricular arrhythmias in vivo. Cardiac-specific deletion of NaV 1.6 protects adult DS mice from increased T-tubular late NaV activity and the resulting arrhythmias, as well as sudden death.

CONCLUSIONS

These data demonstrate that NaV 1.6 undergoes remodeling within T-tubules of adult DS hearts serving as a substrate for Ca2+ -mediated cardiac arrhythmias and may be a druggable target for the prevention of SUDEP in adult DS subjects.

Spontaneous Coronary Artery Dissection Resulting in Acute Myocardial Infarction With Cardiac Rupture

Spontaneous coronary artery dissection occurs predominantly in women and is associated with fibromuscular dysplasia. We illustrate a rare case of sudden coronary death as a result of cardiac rupture from spontaneous coronary artery dissection in a 54-year-old man without fibromuscular dysplasia. Cardiac rupture has been previously reported in 6 cases, mostly in women.

Risk Prediction in Male Adolescents With Congenital Long QT Syndrome: Implications for Sex-Specific Risk Stratification in Potassium Channel-Mediated Long QT Syndrome

BACKGROUND

Sex-specific risk management may improve outcomes in congenital long QT syndrome (LQTS). We recently developed a prediction score for cardiac events (CEs) and life-threatening events (LTEs) in postadolescent women with LQTS. In the present study, we aimed to develop personalized risk estimates for the burden of CEs and LTEs in male adolescents with potassium channel-mediated LQTS.

METHODS AND RESULTS

The prognostic model was derived from the LQTS Registry headquartered in Rochester, NY, comprising 611 LQT1 or LQT2 male adolescents from age 10 through 20 years, using the following variables: genotype/mutation location, QTc-specific thresholds, history of syncope, and β-blocker therapy. Anderson-Gill modeling was performed for the end point of CE burden (total number of syncope, aborted cardiac arrest, and appropriate defibrillator shocks). The applicability of the CE prediction model was tested for the end point of the first LTE (excluding syncope and adding sudden cardiac death) using Cox modeling. A total of 270 CEs occurred during follow-up. The genotype-phenotype risk prediction model identified low-, intermediate-, and high-risk groups, comprising 74%, 14%, and 12% of the study population, respectively. Compared with the low-risk group, high-risk male subjects experienced a pronounced 5.2-fold increased risk of recurrent CEs (P<0.001), whereas intermediate-risk patients had a 2.1-fold (P=0.004) increased risk . At age 20 years, the low-, intermediate-, and high-risk adolescent male patients had on average 0.3, 0.6, and 1.4 CEs per person, respectively. Corresponding 10-year adjusted probabilities for a first LTE were 2%, 6%, and 8%.

CONCLUSIONS

Personalized genotype-phenotype risk estimates can be used to guide sex-specific management in male adolescents with potassium channel-mediated LQTS.

Primary Electrical Heart Disease-Principles of Pathophysiology and Genetics

Primary electrical heart diseases, often considered channelopathies, are inherited genetic abnormalities of cardiomyocyte electrical behavior carrying the risk of malignant arrhythmias leading to sudden cardiac death (SCD). Approximately 54% of sudden, unexpected deaths in individuals under the age of 35 do not exhibit signs of structural heart disease during autopsy, suggesting the potential significance of channelopathies in this group of age. Channelopathies constitute a highly heterogenous group comprising various diseases such as long QT syndrome (LQTS), short QT syndrome (SQTS), idiopathic ventricular fibrillation (IVF), Brugada syndrome (BrS), catecholaminergic polymorphic ventricular tachycardia (CPVT), and early repolarization syndromes (ERS). Although new advances in the diagnostic process of channelopathies have been made, the link between a disease and sudden cardiac death remains not fully explained. Evolving data in electrophysiology and genetic testing suggest previously described diseases as complex with multiple underlying genes and a high variety of factors associated with SCD in channelopathies. This review summarizes available, well-established information about channelopathy pathogenesis, genetic basics, and molecular aspects relative to principles of the pathophysiology of arrhythmia. In addition, general information about diagnostic approaches and management is presented. Analyzing principles of channelopathies and their underlying causes improves the understanding of genetic and molecular basics that may assist general research and improve SCD prevention.

Hypertrophic Cardiomyopathy: A Brief Overview

Hypertrophic cardiomyopathy (HCM) is a complex, heterogeneous disorder that affects approximately 1 in every 500 persons worldwide and about 750,000 Americans. It is characterized by left ventricular hypertrophy that is usually asymmetric, with enlarged myocytes in disarray, unexplained by loading conditions. Obstruction to left ventricular outflow occurs in approximately 60% of patients. The natural history and cardiac morphology of HCM are quite heterogeneous. Although most patients with HCM are asymptomatic or mildly symptomatic, a minority are disabled by dyspnea, angina, or syncope, develop advanced heart failure, or die suddenly.

Arrhythmic risk profile in mitral valve prolapse: A systematic review and metanalysis of 1715 patients

INTRODUCTION

Mitral valve prolapse (MVP) is a common clinical condition in the general population. A subgroup of patients with MVP may experience ventricular arrhythmias and sudden cardiac death ("arrhythmic mitral valve prolapse" [AMVP]) but how to stratify arrhythmic risk is still unclear. Our meta-analysis aims to identify predictive factors for arrhythmic risk in patients with MVP.

METHODS

We systematically searched Medline, Cochrane, Journals@Ovid, Scopus electronic databases for studies published up to December 28, 2022 and comparing AMVP and nonarrhythmic mitral valve prolapse (NAMVP) for what concerns history, electrocardiographic, echocardiographic and cardiac magnetic resonance features. The effect size was estimated using a random-effect model as odds ratio (OR) and mean difference (MD).

RESULTS

A total of 10 studies enrolling 1715 patients were included. Late gadolinium enhancement (LGE) (OR: 16.67; p = .005), T-wave inversion (TWI) (OR: 2.63; p < .0001), bileaflet MVP (OR: 1.92; p < .0001) and mitral anulus disjunction (MAD) (OR: 2.60; p < .0001) were more represented among patients with AMVP than in NAMVP. Patients with AMVP were shown to have longer anterior mitral leaflet (AML) (MD: 2.63 mm; p < .0001), posterior mitral leaflet (MD: 2.96 mm; p < .0001), thicker AML (MD: 0.49 mm; p < .0001), longer MAD length (MD: 1.24 mm; p < .0001) and higher amount of LGE (MD: 1.41%; p < .0001) than NAMVP. AMVP showed increased mechanical dispersion (MD: 8.04 ms; 95% confidence interval: 5.13-10.96; p < .0001) compared with NAMVP.

CONCLUSIONS

Our meta-analysis proved that LGE, TWI, bileaflet MVP, and MAD are predictive factors for arrhythmic risk in MVP patients.

Significant delayed conduction and characteristic ventricular tachycardias in patients with cardiac sarcoidosis and electrical storm

INTRODUCTION

Electrical storm (ES) of ventricular tachyarrhythmias (VTAs) is an important cause of sudden death in patients with cardiac sarcoidosis (CS). VTAs in CS are associated with myocardial scarring and inflammation. However, little is known about the risk factors of ES in patients with CS and VTAs. The objective of this study is to clarify the characteristics and risk factors for the development of ES in patients with CS.

METHODS

The study population included consecutive 52 patients with CS and sustained VTA. Twenty-five out of 52 patients experienced ES. We evaluated clinical characteristics, imaging modalities, and electrocardiogram (ECG) parameters to determine the risk factors associated with ES.

RESULTS

Half of the patients experienced VTAs as the initial symptom of sarcoidosis, and eight patients had ES as the initial VTA episode. There were no differences in cardiac imaging abnormalities between patients with and without ES. Among ECG markers, significant QRS fragmentation (odds ratio [OR]: 7.9, p = .01) and epsilon waves (OR: 12.24, p = .02) were associated with ES. Among the ventricular tachycardia (VT) characteristics, multiple morphologies of monomorphic VTs (OR: 10.9, p < .01), short VT cycle lengths (OR: 12.5, p < .01), and polymorphic VT (OR: 13.5, p < .01) were associated with ES. Bidirectional VTs were detected in 10 patients with ES and one patient without ES. Immunosuppressive therapy relieved ES in some patients.

CONCLUSIONS

ES was common in patients with CS and VTAs. Significant depolarization abnormalities that appeared as QRS fragmentation, epsilon waves, and specific VT characteristics were associated with ES.

Expert opinion on diagnosis and management of epilepsy-associated comorbidities

Apart from seizure freedom, the presence of comorbidities related to neurological, cardiovascular, or psychiatric disorders is the largest determinant of a reduced health-related quality of life in people with epilepsy (PwE). However, comorbidities are often underrecognized and undertreated, and clinical management of comorbid conditions can be challenging. The focus of a comprehensive treatment regimen should maximize seizure control while optimizing clinical management of treatable comorbidities to improve a person's quality of life and overall health. A panel of four European epileptologists with expertise in their respective fields of epilepsy-related comorbidities combined the latest available scientific evidence with clinical expertise and collaborated to provide consensus practical advice to improve the identification and management of comorbidities in PwE. This review provides a critical evaluation for the diagnosis and management of sleep-wake disorders, cardiovascular diseases, cognitive dysfunction, and depression in PwE. Whenever possible, clinical data have been provided. The PubMed database was the main search source for the literature review. The deleterious pathophysiological processes underlying neurological, cardiovascular, or psychiatric comorbidities in PwE interact with the processes responsible for generating seizures to increase cerebral and physiological dysfunction. This can increase the likelihood of developing drug-resistant epilepsy; therefore, early identification of comorbidities and intervention is imperative. The practical evidence-based advice presented in this article may help clinical neurologists and other specialist physicians responsible for the care and management of PwE.

Risk stratifier for sudden cardiac death beyond the left ventricular ejection fraction in Chagas cardiomyopathy

BACKGROUND

Sudden cardiac death (SCD) risk markers are needed in Chagas cardiomyopathy (CC). Action potential duration restitution (APDR) dynamics is capable of extracting information on cardiac regional heterogeneity. This study intends to develop a patient-specific variables-based algorithm to predict SCD in the low-intermediate subgroups of the Rassi risk score.

METHODS

Cross-sectional study of patients who underwent 24-h Holter for research purposes between January 1992 and February 2017. From 4-h ECG segment, RR series were generated and APDR dynamics metrics were calculated. Classification tree and sensitivity analysis were applied. As outcomes, SCD, SCD-free and non-cardiovascular death and 34 variables were included.

RESULTS

Two hundred twenty-one (129 in the group SCD-free, 80 in the SCD group and 12 non-cardiovascular death group) were analyzed. In the groups with and without SCD (209 patients), the median age was 66 years, 52% were female, the cardiac involvement was mild to moderate in 72% with a Rassi point median of 8 (IQ: 3 to 11). The SCD group had more ventricular remodeling and more ventricular electrical instability. The occurrence of a %beats QTend/TendQ ratio > 1 (AUC, 0.96 (95% CI 0.89-0.98) present in more than 56.7% of the 4-h ECG segments was sufficient to identify patients of the SCD subgroup. Variables representing different stages of CC were also relevant in the model.

CONCLUSION

It is possible to use APDR dynamics as an adjuvant in the SCD risk assessment in a subgroup of patients with a high risk of SCD and a very low risk of non-CV death with high power of discrimination.