Temporal Trends in the Clinical and Pathological Characteristics of Victims of Sudden Cardiac Death in the Absence of Previously Identified Heart Disease

Advancements in automated external and wearable cardiac defibrillators

PURPOSE OF REVIEW

Survival statistics for out-of-hospital cardiac arrests remain unsatisfactory. Prompt defibrillation of shockable rhythms, such as ventricular fibrillation and pulseless ventricular tachycardia, is crucial for improving survival. Automated external defibrillators (AEDs) and wearable cardiac defibrillators (WCDs) seek to improve the survival rates following out-of-hospital cardiac arrests. We aim to review the indications, utility, advancements, and limitations of AEDs and WCDs, as well as their role in contemporary and future clinical practice.

RECENT FINDINGS

Recent advancements in these technologies, such as smartphone applications and drone delivery of AEDs and less inappropriate shocks and decreased size of WCDs, have increased their ubiquity and efficacy. However, implementation of this technology remains limited due to lack of resources and suboptimal patient adherence.

SUMMARY

Out of hospital cardiac arrests continue to pose a significant public health challenge. Advancements in AEDs and WCDs aim to facilitate prompt defibrillation of shockable rhythms with the goal of improving survival rates. However, they remain underutilized due to limited resources and suboptimal patient adherence. As these technologies continue to evolve to become smaller, lighter and more affordable, their utilization and accessibility are expected to improve.

Use of strain imaging to detect subtle myocardial involvement in post COVID-19 patients: An Indian perspective

BACKGROUND

The study assessed Global longitudinal strain imaging (GLS) to detect subtle myocardial dysfunction among patients clinically recovered from COVID-19.

METHODS

All patients (n = 101 76 % males, mean age 55.45 ± 11.14 years), and controls (n = 30), underwent clinical assessment and echocardiography, including GLS assessment.

RESULTS

The prevalence of diabetes mellitus, hypertension and dyslipidemia was comparable amongst patients and controls. The average GLS was significantly lesser in post COVID patients (-16.21 ± 1.96 vs -18.49 ± 1.64 respectively, p = 0.004) and significantly higher proportion of post COVID patients had GLS > -18 % (43 % vs 22.58 % respectively, p = 0.001) as compared to controls. The RV free wall longitudinal strain (RVFLS) was also lower in the patient group (22.35 ± 4.69 vs 24.19 ± 4.11, p = 0.004) and 21.7 % post COVID-19 patients had pathological RV FWLS (> -20 %) vs controls (6.6 %). Average GLS was significantly lesser in severe post COVID patients (viz -14.25 ± 1.92 vs -16.63 ± 1.61 vs -17.63 ± 1.91, p < 0.0001, respectively among severe, moderate and mild COVID-19 patients. On performing regression analysis, severity of COVID-19 (OR 7.762) was a significant predictor of impaired GLS.

CONCLUSION

Despite normal global LVEF, post COVID-19 recovered patients had significantly lower LV GLS and RV FWLS with severe COVID-19 infection, regardless of having a clinical recovery. This study reiterates the importance of speckle tracking echocardiography as an important imaging modality for detection of subclinical myocardial dysfunction in the post COVID-19 recovered patients.

Comorbidities prior to out-of-hospital cardiac arrest and diagnoses at discharge among survivors

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) has a dismal prognosis with overall survival around 10%. Previous studies have shown conflicting results regarding the prevalence and significance of comorbidities in OHCA, as well as the underlying causes. Previously, 80% of sudden cardiac arrest have been attributed to coronary artery disease. We studied comorbidities and discharge diagnoses in OHCA in all of Sweden.

METHODS

We used the Swedish Registry of Cardiopulmonary Resuscitation, merged with the Inpatient Registry and Outpatient Registry to identify patients with OHCA from 2010 to 2020 and to collect all their comorbidities as well as discharge diagnoses (among those admitted to hospital). Patient characteristics were described using means, medians and SD. Survival curves were performed among hospitalised patients with acute myocardial infarction (AMI) as well as heart failure.

RESULTS

A total of 54 484 patients with OHCA were included, of whom 35 894 (66%) were men. The most common comorbidities prior to OHCA were hypertension (43.6%), heart failure (23.6%), chronic ischaemic heart disease (23.6%) and atrial fibrillation (22.0%). Previous AMI was prevalent in 14.8% of men and 10.9% of women. Among women, 18.0% had type 2 diabetes, compared with 19.6% of the men. Among hospitalised patients, 30% were diagnosed with AMI, 27% with hypertension, 20% with ischaemic heart disease and 18% with heart failure as discharge diagnoses.

CONCLUSION

In summary, we find evidence that nowadays a minority of cardiac arrests are due to coronary artery disease and AMIs and its complications. Only 30% of all cases of OHCA admitted to hospital were diagnosed with AMI. Coronary artery disease is now likely in the minority with regard to causes of OHCA.

The Lancet Commission to reduce the global burden of sudden cardiac death: a call for multidisciplinary action

Despite major advancements in cardiovascular medicine, sudden cardiac death (SCD) continues to be an enormous medical and societal challenge, claiming millions of lives every year. Efforts to prevent SCD are hampered by imperfect risk prediction and inadequate solutions to specifically address arrhythmogenesis. Although resuscitation strategies have witnessed substantial evolution, there is a need to strengthen the organisation of community interventions and emergency medical systems across varied locations and health-care structures. With all the technological and medical advances of the 21st century, the fact that survival from sudden cardiac arrest (SCA) remains lower than 10% in most parts of the world is unacceptable. Recognising this urgent need, the Lancet Commission on SCD was constituted, bringing together 30 international experts in varied disciplines. Consistent progress in tackling SCD will require a completely revamped approach to SCD prevention, with wide-sweeping policy changes that will empower the development of both governmental and community-based programmes to maximise survival from SCA, and to comprehensively attend to survivors and decedents' families after the event. International collaborative efforts that maximally leverage and connect the expertise of various research organisations will need to be prioritised to properly address identified gaps. The Commission places substantial emphasis on the need to develop a multidisciplinary strategy that encompasses all aspects of SCD prevention and treatment. The Commission provides a critical assessment of the current scientific efforts in the field, and puts forth key recommendations to challenge, activate, and intensify efforts by both the scientific and global community with new directions, research, and innovation to reduce the burden of SCD worldwide.

Sudden arrhythmic death and cardiomyopathy are important causes of sudden cardiac death in the UK: results from a national coronial autopsy database

AIMS

Sudden cardiac death (SCD) is defined as natural unexpected death in witnessed cases occurring < 1 h and in unwitnessed cases as last seen alive < 24 h. SCD due to ischaemic heart disease (IHD) is frequent in older age groups; in younger people genetic cardiac causes, including channelopathies and cardiomyopathies, are more frequent. This study aimed to present the causes of SCD from a large specialist pathology registry.

METHODS AND RESULTS

Cases were examined macroscopically and microscopically by two expert cardiac pathologists. The hearts from 7214 SCD cases were examined between 1994 and 2021. Sudden arrhythmic death syndrome (SADS), a morphologically normal heart, which can be underlaid by cardiac channelopathies, is most common (3821, 53%) followed by the cardiomyopathies (1558, 22%), then IHD (670, 9%), valve disease (225, 3%), congenital heart disease (213, 3%) and myocarditis/sarcoidosis (206, 3%). Hypertensive heart disease (185, 3%), aortic disease (129, 2%), vascular disease (97, 1%) and conduction disease (40, 1%) occur in smaller proportions.

DISCUSSION

To our knowledge, this is the largest SCD cohort with autopsy findings ever reported from one country. SADS and cardiomyopathies predominate. This study highlights the importance of the autopsy in SCD, which is a significant public health concern in all age groups. Knowing the true incidence in our population will improve risk stratification and develop preventative strategies for family members. There is now a national pilot study integrating molecular autopsy and family screening into the assessment of SCD victims.

Long-term prognosis of out-of-hospital cardiac arrest due to idiopathic ventricular arrhythmias

Life-threatening ventricular arrhythmias (VA) may occur in patients with unknown cardiac disease. A sizable part of them remains labeled as Idiopathic VA and limited data is available regarding their natural history. Our aim was to evaluate the long-term clinical outcomes of survivors of an idiopathic life-threatening VA. Patients who survived an idiopathic life-threatening VA referred to an ICD were included and followed for a median follow-up of 7 years. Clinical and device data were collected and a comparison between genders was made. A total of 29 patients, 41% female, mean age of 50 (19) years were studied; all were implanted with an ICD at index hospitalization. At follow-up, an etiological diagnosis was established in 38% of patients. Genetic testing improved the diagnosis and allowed the identification of a distinct clinical entity in 60% of patients (p=0.04, OR=7.0), especially in women. Regarding ICD data, 31% received appropriate therapies with a median time to first appropriate shock of 39 months (IQR 12-46 months). Men had a significantly higher prevalence of appropriated shocks (50% vs 8%, p=0.04), with a similar time to the first arrhythmic event between genders. Two of the patients died, both from non-arrhythmic causes. Etiologic diagnosis and recurrence prediction in patients with idiopathic VA is challenging, even with long-term follow-up and sophisticated diagnostic evaluation.  Genetic testing significantly improved the diagnostic yield, especially in women. Arrhythmia recurrence occurred in about one-third of patients and is significantly higher in men, underscoring the importance of ICD implantation.

Clinical profile and the extent of residual myocardial dysfunction among patients with previous coronavirus disease 2019

BACKGROUND

Many patients who have recovered from their coronavirus disease 2019 (COVID-19) episode continue to remain symptomatic and seek medical opinion. The clinical characteristics and echocardiography findings of such subjects have not been adequately studied.

METHODS

The study included 472 subjects (age 54.0 ± 13.4 years, 57% men) with previous COVID-19 (median duration since COVID-19 12.0 weeks, interquartile range 9.0-26.0 weeks) and 100 controls (age 53.9 ± 13.6 years, 53% men). All subjects underwent detailed clinical assessment and echocardiography, including measurement of left ventricular (LV) ejection fraction (EF) and global longitudinal strain (GLS).

RESULTS

Less than third (29.2%) of the post-COVID subjects had needed hospitalization for their initial infection. Exertional dyspnea or breathing difficulty at rest were the commonest reasons for post-COVID presentation. As compared to controls, the post-COVID subjects had impaired LV systolic (LVEF 63.2 ± 2.2 vs. 61.9 ± 4.6, P = 0.007; GLS - 19.9 ± 2.6% vs. -17.6 ± 3.4%, P < 0.001) and diastolic function. Majority of those with reduced LV GLS had preserved LVEF. The patients presenting before 12 weeks were more likely to be symptomatic, but LV GLS did not differ. The patients needing hospitalization had higher burden of co-morbidities and significantly reduced LV GLS as compared to those who had received domiciliary treatment. The patients in the lowest GLS tertile were older, had higher burden of co-morbidities, and had had more severe initial infection with greater need for hospitalization, oxygen therapy and steroids. The need for hospitalization was independently associated with lower GLS at the time of current presentation.

CONCLUSION

This study shows that impairment of LV systolic and diastolic function is common among subjects recovering from previous COVID-19 episode. The patients with more severe initial infection have more marked impairment of LV function and this impairment persists even after several months of recovery from the initial infection. Routine measurement of GLS may be helpful since LV systolic dysfunction in these patients is mostly subclinical.

Plaque histology and myocardial disease in sudden coronary death: the Fingesture study

AIMS

At least 50% of deaths due to coronary artery disease (CAD) are sudden cardiac deaths (SCDs), but the role of acute plaque complications on the incidence of sudden death in CAD is somewhat unclear. The present study aimed to investigate plaque histology and concomitant myocardial disease in sudden coronary death.

METHODS AND RESULTS

The study population is derived from the Fingesture study, which has collected data from 5869 consecutive autopsy-verified SCD victims in Northern Finland (population ≈600 000) between 1998 and 2017. In this substudy, histological examination of culprit lesions was performed in 600 SCD victims whose death was due to CAD. Determination of the cause of death was based on the combination of medical records, police reports, and autopsy data. Plaque histology was classified as either (i) plaque rupture or erosion, (ii) intraplaque haemorrhage, or (iii) stable plaque. The mean age of the study subjects was 64.9 ± 11.2 years, and 82% were male. Twenty-four per cent had plaque rupture or plaque erosion, 24% had an intraplaque haemorrhage, and 52% had a stable plaque. Myocardial hypertrophy was present in 78% and myocardial fibrosis in 93% of victims. The presence of myocardial hypertrophy or fibrosis was not associated with specific plaque histology.

CONCLUSION

Less than half of sudden deaths due to CAD had evidence of acute plaque complication, an observation which is contrary to historical perceptions. The prevalence of concomitant myocardial disease was high and independent of associated plaque morphology.

Case Report: Identification of the First Synonymous Variant of Myosin Binding Protein C3 (c.24A>C, p.P8P) Altering RNA Splicing in a Cardiomyopathy and Sudden Cardiac Death Case

Background

Sudden cardiac death (SCD), based on sudden cardiac ejection cessation, is an unexpected death. Primary cardiomyopathies, including dilated cardiomyopathy (DCM), are one of main causes of SCD. The DCM is characterized by a cardiac dilatation and a reduced systolic function with a prevalence of 1/250 in adults. The DCM has been reported with more than 60 disease-causing genes, and MYBPC3 variants are one of the most common and well-known causes of DCM.

Methods

We identified a 29-year-old female who died of SCD. We performed a whole-exome sequencing (WES) to detect her genetic etiology and used minigene modeling and immunohistochemistry staining to verify the pathogenicity.

Results

We determined that the woman died of SCD caused by DCM due to an identified novel synonymous variant of MYBPC3 (NM_000256.3: c.24A>C, p.P8P) in the deceased. The variant can result in abnormal splicing, which was confirmed by minigene models and immunohistochemistry staining.

Conclusion

We may have identified the first deleterious synonymous variant of MYBPC3 in an SCD case and verified its significant impact on RNA splicing. Our description enriched the spectrum of MYBPC3 variants and emphasized the significance of synonymous variants that are always disregarded in genetic screening.

Temporal Trends in the Incidence and Characteristics of Sudden Cardiac Death Among Subjects Under 40 Years of Age in Northern Finland During 1998-2017

Background: Although the mean age of sudden cardiac death (SCD) victims has increased during recent decades, overall incidence has remained relatively stable. Small but very important proportion of SCDs occur in subjects under 40 years of age and temporal trends in the incidence and characteristics of SCD in this age group are not well known. Methods: The Fingesture study has prospectively gathered data from 5,869 consecutive autopsy verified SCD victims in Northern Finland during 1998-2017. On the basis of Finnish law, all who die unexpectedly undergo autopsy. Results: Out of total 5,869 SCDs, 160 occurred in subjects under 40 years of age (3%) indicating a total incidence of 2.9/100,000/year. Incidence decreased during the study period; 4.0/100,000/year (n=50) in 1998-2002, 3.7/100,000/year (n=45) in 2003-2007, 2.5/100,000/year (n=36) in 2008-2012 and 1.5/100,000/year (n=29) in 2013-2017. Coronary artery disease (CAD) was the cause of death in 46 SCD victims (29%). Among non-ischemic causes, most common were obesity-related hypertrophic myocardial disease (24%), primary myocardial fibrosis (19%) and hypertensive myocardial disease (6%). The incidence of SCD caused by CAD decreased as follows; 1.5/100,000/year in 1998-2002, 1.2/100,000/year in 2003-2007, 0.6/100,000/year in 2008-2012 and 0.2/100,000/year in 2013-2017. Proportion of male gender (81%) and obesity as a comorbidity (body mass index >30 kg/m2, 40%) remained relatively stable during the period (p=0.58 and p=0.79, respectively). Conclusions: The incidence of SCD in subjects under 40 years of age has decreased in Northern Finland during 1998-2017. According to autopsy data, most of the deaths are due to non-ischemic myocardial diseases and relative proportion of CAD has decreased.

Post-Acute Sequelae of SARS-COVID-2 Syndrome: Just the Beginning

Viral diseases are some of the most common infections affecting humans. Despite the unpleasant symptoms, most people return to their normal lives without residual symptoms. Following the acute infectious phase of some viruses, however, in some individuals symptoms may linger to the extent they are unable to return to a normal lifestyle. Following coronavirus disease 2019 infection, significant numbers of patients continued to have symptoms that persisted for months after hospital discharge. Symptoms spanned many organ systems and were prominent in the pulmonary and cardiovascular systems. The exact mechanism is not clear. This group of patients represents a new challenge to our health care systems. An organized, multi-disciplinary approach and further research are warranted to be ready to deliver better care to these patients.

Temporal trends and sex differences in sudden cardiac death in the Copenhagen City Heart Study

OBJECTIVE

More knowledge about the development of sudden cardiac death (SCD) in the general population is needed to develop meaningful predictors of SCD. Our aim with this study was to estimate the incidence of SCD in the general population and examine the temporal changes, demographics and clinical characteristics.

METHODS

All participants in the Copenhagen City Heart Study were followed from 1993 to 2016. All death certificates, autopsy reports and national registry data were used to identify all cases of SCD.

RESULTS

A total of 14 562 subjects were included in this study. There were 8394 deaths with all information available, whereof 1335 were categorised as SCD. The incidence of SCD decreased during the study period by 41% for persons aged 40-90 years, and the standardised incidence rates decreased from 504 per 100 000 person-years (95% CI 447 to 569) to 237 per 100 000 person-years (95% CI 195 to 289). The incidence rate ratio of SCD between men and women ≤75 years was 1.99 (95% CI 1.62 to 2.46). The proportion of SCD of all cardiac deaths decreased during the observation period and decreased with increasing age. Men had more cardiovascular comorbidities (OR 1.34, 95% CI 1.07 to 1.68, p<0. 01), and SCD was the first registered manifestation of cardiac disease in 50% of all cases.

CONCLUSION

The incidence of SCD in the general population has declined significantly during the study period but should be further investigated for more recent variations as well as novel risk predictors for persons with low to medium risk of SCD.

Coronary Artery Disease as the Cause of Sudden Cardiac Death Among Victims < 50 Years of Age

Coronary artery disease (CAD) is the most common cause of sudden cardiac death (SCD). Atherosclerosis increases with age, but also many victims of SCD in young and middle-aged population have CAD at autopsy. The purpose of this study was to determine the characteristics and autopsy findings of SCD due to CAD among victims of SCD under the age of 50. Fingesture is a population-based study consisting of consecutive series of victims of autopsy verified SCD in Northern Finland between the years 1998 to 2017 (n = 5,869). Histological examinations were part of all autopsies and a toxicology investigation was performed if needed. Analyses included information accumulated from death certificates, medical records, autopsy data, standardized questionnaire to the closest family members of the victims of SCD and police reports of the conditions of the death. Overall, 10.4% of all SCDs occurred among victims under the age of 50 years (610 victims). Most common underlying cause of SCD among these younger SCD victims was CAD (43.6%). The prevalence of CAD as the cause of SCD became more common in young SCD victims after the age of 35 years. The mean age of ischemic SCD victims was 44±5 years and most were men (89.5%). Most victims (90.2%) had no clinical diagnosis of CAD, however 33.8% had an autopsy evidence of silent myocardial infarction. SCD occurred during physical activity in 24.1%. Three-vessel disease was detected in 44.4% of the study victims. Cardiac hypertrophy (58.3%) and myocardial fibrosis (82.6%) were also common. At least 1 cardiovascular risk factor was present in 64.7% of SCD victims. In conclusion, most SCDs among victims < 50 years of age are due to CAD.

Prognostic value of soluble suppression of tumorigenesis-2 (sST2) for cardiovascular events in coronary artery disease patients with and without diabetes mellitus

Background

Soluble suppression of tumorigenesis-2 (sST2) is implicated in myocardial overload and has long been recognized as an inflammatory marker related to heart failure and acute coronary syndrome, but data on the prognostic value of sST2 in patients with coronary artery disease (CAD) remain limited. This study sought to investigate the prognostic value of sST2 in patients with established CAD and its predictive value in CAD patients with and without type 2 diabetes mellitus (T2DM).

Methods

A total of 3641 consecutive patients were included in this prospective cohort study. The primary end point was major adverse cardiovascular events (MACEs). The secondary end point was all-cause death. The association between sST2 and outcomes was investigated using multivariable Cox regression.

Results

During a median follow-up of 6.4 years, MACEs occurred in 775 patients, and 275 patients died. Multiple Cox regression models showed that a higher level of sST2 was an independent predictor of MACEs development (HR = 1.36, 95% CI 1.17–1.56, p < 0.001) and all-cause death (HR = 2.01, 95% CI 1.56–2.59, p < 0.001). The addition of sST2 to established risk factors significantly improved risk prediction of the composite outcome of MACEs and all-cause death (C-index, net reclassification index, and integrated discrimination improvement, all p < 0.05). In subgroup analysis depending on diabetes status, the diabetes group had a significantly higher level of sST2, which remained a significant predictor of MACEs and all-cause death in patients with and without T2DM in multivariable models. The area under the curve (AUC) of CAD patients with diabetes mellitus was significantly higher than that of those without T2DM. For MACEs, the AUC was 0.737 (patients with T2DM) vs 0.620 (patients without T2DM). For all-cause death, the AUC was 0.923 (patients with T2DM) vs 0.789 (patients without T2DM).

Conclusions

A higher level of sST2 is significantly associated with long-term MACEs and all-cause death in CAD patients with and without T2DM. sST2 has strong predictive value for cardiovascular adverse events in CAD patients with T2DM, and these results provide new evidence for the role of sST2.

COVID-19 cardiac injury: Implications for long-term surveillance and outcomes in survivors

Up to 20%-30% of patients hospitalized with coronavirus disease 2019 (COVID-19) have evidence of myocardial involvement. Acute cardiac injury in patients hospitalized with COVID-19 is associated with higher morbidity and mortality. There are no data on how acute treatment of COVID-19 may affect the convalescent phase or long-term cardiac recovery and function. Myocarditis from other viral pathogens can evolve into overt or subclinical myocardial dysfunction, and sudden death has been described in the convalescent phase of viral myocarditis. This raises concerns for patients recovering from COVID-19. Some patients will have subclinical and possibly overt cardiovascular abnormalities. Patients with ostensibly recovered cardiac function may still be at risk of cardiomyopathy and cardiac arrhythmias. Screening for residual cardiac involvement in the convalescent phase for patients recovered from COVID-19-associated cardiac injury is needed. The type of testing and therapies for post COVID-19 myocardial dysfunction will need to be determined. Therefore, now is the time to plan for appropriate registries and clinical trials to properly assess these issues and prepare for long-term sequelae of "post-COVID-19 cardiac syndrome."

Sudden Cardiac Death in the Young: Incidence, Trends, and Risk Factors in a Nationwide Study

BACKGROUND

Sudden cardiac death (SCD) in the young is devastating. Contemporary incidence remains unclear with few recent nationwide studies and limited data addressing risk factors for causes. We aimed to determine incidence, trends, causes, and risk factors for SCD in the young.

METHODS AND RESULTS

The National Coronial Information System registry was reviewed for SCD in people aged 1 to 35 years from 2000 to 2016 in Australia. Subjects were identified by the International Classification of Diseases, Tenth Revision code relating to circulatory system diseases (I00-I99) from coronial reports. Baseline demographics, circumstances, and cause of SCD were obtained from coronial and police reports, alongside autopsy and toxicology analyses where available. During the study period, 2006 cases were identified (median age, 28±7 years; men, 75%; mean body mass index, 29±8 kg/m²). Annual incidence ranged from 0.91 to 1.48 per 100 000 age-specific person-years, which was the lowest in 2013 to 2015 compared with previous 3-year intervals on Poisson regression model (P=0.001). SCD incidence was higher in nonmetropolitan versus metropolitan areas (0.99 versus 0.53 per 100 000 person-years; P<0.001). The most common cause of SCD was coronary artery disease (40%), followed by sudden arrhythmic death syndrome (14%). Incidence of coronary artery disease-related SCD decreased from 2001-2003 to 2013-2015 (P<0.001). Proportion of SCD related to sudden arrhythmic death syndrome increased during the study period (P=0.02) although overall incidence was stable (P=0.22). Residential remoteness was associated with coronary artery disease-related SCD (odds ratio, 1.44 [95% CI, 1.24-1.67]; P<0.001). For every 1-unit increase, body mass index was associated with increased likelihood of SCD from cardiomegaly (odds ratio, 1.08 [95% CI, 1.05-1.11]; P<0.001) and dilated cardiomyopathy (odds ratio, 1.04 [95% CI, 1.01-1.06]; P=0.005).

CONCLUSIONS

Incidence of SCD in the young and specifically coronary artery disease-related SCD has declined in recent years. Proportion of SCD related to sudden arrhythmic death syndrome increased over the study period. Geographic remoteness and obesity are risk factors for specific causes of SCD in the young.

Galactin-3 and soluble ST2 as complementary tools to cardiac MRI for sudden cardiac death risk stratification in heart failure: A review

Heart failure (HF) is recognized as one of the leading causes of morbidity and mortality worldwide. Every year about 500,000 new cases of HF are diagnosed in the United States. The predominant etiology of death in HF patients include sudden cardiac death (SCD) and pump failure. Prediction of mode of death may help in devising management decisions. In patients with HF, the presence of myocardial fibrosis has been a known risk factor for SCD and thus it could be used as a criterion in risk stratification for SCD. However, the underlying pathophysiology of SCD is uncertain and controversial, which makes it necessary to develop newer tools to enhance SCD risk stratification. The newer tools should be innovative enough either to complement or to replace the currently available tools. In this scoping review, we highlighted the utilization of novel biomarkers galectin-3 (gal-3) and soluble ST2 (sST2) and discussed that how they might complement currently available tools such as, cardiac MRI (CMR) for SCD risk stratification in HF patients.

Combined evaluation of ambulatory-based late potentials and nonsustained ventricular tachycardia to predict arrhythmic events in patients with previous myocardial infarction: A Japanese noninvasive electrocardiographic risk stratification of sudden cardiac death (JANIES) substudy

Background

Noninvasive electrocardiographic (ECG) markers are promising arrhythmic risk stratification tools for identifying sudden cardiac death. However, little is known about the usefulness of noninvasive ECG markers derived from ambulatory ECGs (AECG) in patients with previous myocardial infarction (pMI). We aimed to determine whether the ECG markers derived from AECG can predict serious cardiac events in patients with pMI.

Methods

We prospectively analyzed 104 patients with pMI (88 males, age 66 ± 11 years), evaluating late potentials (LPs), heart rate turbulence, and nonsustained ventricular tachycardia (NSVT) derived from AECG. The primary endpoint was the documentation of ventricular fibrillation or sustained ventricular tachycardia.

Results

Eleven patients reached the primary endpoint during a follow‐up period of 25 ± 9.5 months. Of the 104 patients enrolled in this study, LP positive in worst values (w‐LPs) and NSVT were observed in 25 patients, respectively. In the arrhythmic event group, the worst LP values and/or NSVT were found in eight patients (7.6%). The positive predictive and negative predictive values of the combined assessment with w‐LPs and NSVT were 56% and 94%, respectively, for predicting ventricular lethal arrhythmia. Kaplan–Meier analysis demonstrated that the combination of w‐LPs and NSVT had a poorer event‐free period than negative LPs (p < .0001). In the multivariate analysis, the combined assessment of w‐LPs and NSVT was a significant predictor of arrhythmic events (hazard ratio = 14.1, 95% confidence intervals: 3.4–58.9, p < .0001).

Conclusion

Combined evaluation of w‐LPs and NSVT was a powerful risk stratification strategy for predicting arrhythmia that can lead to sudden cardiac death in patients with pMI.

HIV and cardiovascular disease

HIV-related cardiovascular disease research is predominantly from Europe and North America. Of the estimated 37·9 million people living with HIV worldwide, 25·6 million live in sub-Saharan Africa. Although mechanisms for HIV-related cardiovascular disease might be the same in all people with HIV, the distribution of cardiovascular disease risk factors varies by geographical location. Sub-Saharan Africa has a younger population, higher prevalence of elevated blood pressure, lower smoking rates, and lower prevalence of elevated cholesterol than western Europe and North America. These variations mean that the profile of cardiovascular disease differs between low-income and high-income countries. Research in, implementation of, and advocacy for risk reduction of cardiovascular disease in the global context of HIV should account for differences in the distribution of traditional cardiovascular disease risk factors (eg, hypertension, smoking), consider non-traditional cardiovascular disease risk factors (eg, access to antiretroviral therapy with more benign cardiovascular disease side effect profiles, indoor air pollution), and encourage the inclusion of relevant risk reduction approaches for cardiovascular disease in HIV-care guidelines. Future research priorities include implementation science to scale up and expand integrated HIV and cardiovascular disease care models, which have shown promise in sub-Saharan Africa; HIV and cardiovascular disease epidemiology and mechanisms in women; and tobacco cessation for people living with HIV.

Electrocardiographic associations with myocardial fibrosis among sudden cardiac death victims

OBJECTIVE

A major challenge in reducing the incidence of sudden cardiac death (SCD) is the identification of patients at risk. Myocardial fibrosis has a substantial association with SCD risk but is difficult to identify among general populations. Our aim was to find electrocardiographic (ECG) markers of myocardial fibrosis among SCD victims.

METHODS

Study population was acquired from the Fingesture study, which has gathered data from 5869 consecutive autopsied SCD victims in Northern Finland between 1998 and 2017. The degree of fibrosis was determined in histological samples taken from the heart during autopsy and was categorised into four groups: (1) no fibrosis, (2) scattered mild fibrosis, (3) moderate patchy fibrosis and (4) substantial fibrosis. We were able to collect ECGs from 1100 SCD victims.

RESULTS

The mean age of the study subjects was 66±13 years and 75% were male. QRS duration in ECG correlated with the degree of fibrosis (p<0.001, β=0.153). Prevalence of fragmented QRS complex, pathological Q waves and T wave inversions correlated with increased degree of fibrosis (p<0.001 in each). Depolarisation abnormalities were observed both in ischaemic and non-ischaemic heart disease. Repolarisation abnormalities reached statistical significance only among ischaemic SCD victims. An abnormal ECG was observed in 75.3% of the subjects in group 1, 73.7% in group 2, 88.5% in group 3 and 91.7% in group 4 patients (p<0.001).

CONCLUSIONS

Myocardial fibrosis was associated with QRS prolongation, deep Q waves, T wave inversions and QRS fragmentation. The results provide potentially useful non-invasive early recognition of patients with fibrotic cardiomyopathy and risk of SCD.

Low myocardial transcript variant alt-a of cyclin dependent kinase inhibitor p21 expression differentiates hypothermia from cardiac/respiratory causes of death

Gene expressions in the myocardium have been shown to vary between different causes of death, which can be utilized in the recognition of varied processes. Our previous work with a limited number of cases showed a high messenger ribonucleic acid expression of the transcript variant alt-a of cyclin dependent kinase inhibitor p21 (p21 alt-a) in chronic cardiac ischemia deaths and a low expression in hypothermia deaths and acute myocardial ischemia deaths. In present work, p21 alt-a expression in the myocardium of human cadavers was calculated using glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as reference gene. In this collection of 143 samples, the p21 alt-a expression was significantly lower in hypothermia than in chronic cardiac ischemic heart disease with (P < .001) or without (P < .001) acute myocardial infarction and in other cardiac and respiratory disease deaths (P < .000). Chronic ischemic heart disease in hypothermia cases did not increase the expression. The p21 alt-a expression did not correlate with postmortem interval, quality of RNA or with the age of the deceased. The p21 alt-a referenced to GAPDH expression in cadaver myocardium has apparent potential as a marker distinguishing between hypothermia and cardiac/respiratory diseases as causes of death.

Coronary Artery Disease and Atherosclerotic Risk Factors in a Population-Based Study of Sudden Death

BACKGROUND

Sudden death is a public health problem with major impact on society. Coronary artery disease (CAD) is believed to underlie 60-80% of these deaths. While deaths from CAD have decreased in the recent decades, sudden death rates remain unacceptably high.

OBJECTIVE

We aimed to assess the prevalence of CAD and its risk factors among 18-64-year-old adults in a population-based case registry of sudden deaths and compare them to a living population from the same geographical area.

DESIGN

From 2013 to 2015, all sudden deaths among 18-64-year-old adults in Wake County, NC, were identified (n = 371). A comparison group was formed by randomly selecting individuals from an electronic health record repository of a major healthcare system in the area (N = 4218).

MAIN MEASURES

Prevalence of CAD and its risk factors among cases of sudden death and living population across sex and age groups. Odds of sudden death associated with atherosclerotic risk factors and comorbidities.

KEY RESULTS

CAD was present in 14.8% of sudden death cases. Among sudden death victims, most risk factors and comorbidities were more common in the older age group, except for obesity which was more common in younger cases, and diabetes which was equally prevalent in younger and older cases. Compared to living population, sudden death cases had higher prevalence of atherosclerotic risk factors across all gender and age groups. Sudden death cases had a numerically higher number of risk factors compared to living population, regardless of age group or presence of CAD.

CONCLUSIONS

Coronary artery disease is not common among sudden death cases, but risk factors and comorbidities are prevalent. Our findings support the changing etiology of sudden death. In the absence of clinically diagnosed CAD, use of novel imaging modalities and biomarkers may identify high-risk individuals and lead to prevention of sudden death.

Sudden Cardiac Death in Women

BACKGROUND

Despite recent progress in profiling of risk for sudden cardiac death (SCD) and prevention and intervention of cardiac diseases, SCD remains a major cause of death. Among women, the incidence of SCD is significant, but lower than in men, particularly in the premenopausal and early postmenopausal years. Possibly, as a consequence of the difference in population burden, the mechanisms and risk markers of SCD are not as well defined for women. The aim of this study was to determine the autopsy findings and causes of death among women in a large SCD population. Additionally, we sought to classify prior ECG characteristics in male and female subjects with SCD.

METHODS

The Fingesture study has systematically collected clinical and autopsy data from subjects with SCD in Northern Finland between 1998 and 2017. The cohort consists of 5869 subjects with SCD. Previously recorded ECGs were available and analyzed in 1101 subjects (18.8% of total population; and in 25.3% of women).

RESULTS

Female subjects with SCD were significantly older than men: 70.1±13.1 years versus 63.5±11.8 years (mean ± standard deviation, P<0.001). The most frequently identified cause of death was ischemic heart disease in both sexes: 71.7% among women versus 75.7% among men, P=0.005. In contrast, women were more likely to have nonischemic cause of SCD than men (28.3% versus 24.3%, P=0.005). The prevalence of primary myocardial fibrosis was higher among women (5.2%, n=64) than in men (2.6%, n=120; P<0.001). Female subjects with SCD were more likely to have normal prior ECG tracings (22.2% versus 15.3% in men, P<0.001). A normal ECG was even more common among nonischemic female subjects with SCD (27.8% versus 16.2% in men, P=0.009). However, ECG markers of left ventricular hypertrophy, with or without repolarization abnormalities, were more common among women (8.2%; 17.9%) than in men (4.9%; 10.6%, P=0.036; P<0.001, respectively).

CONCLUSIONS

Women were considerably older at the time of SCD and more commonly had nonischemic causes. Women were also more likely to have a prior normal ECG than men, but an increased marker for SCD risk based on ECG criteria for left ventricular hypertrophy with repolarization abnormalities was more commonly observed in women.

Sudden Cardiac Death: Who Is at Risk?

Sudden cardiac death (SCD) is a leading cause of death in the United States. Despite improvements in therapy, the incidence of SCD as a proportion of overall cardiovascular death remains relatively unchanged. This article aims to answer the question, "Who is at risk for SCD?" In the process, it reviews the definition, pathophysiology, epidemiology, and risk factors of SCD. Patients at risk for SCD and appropriate treatment strategies are discussed.

Primary Myocardial Fibrosis as an Alternative Phenotype Pathway of Inherited Cardiac Structural Disorders

BACKGROUND

Myocardial fibrosis is a common postmortem finding among young individuals with sudden cardiac death. Because there is no known single cause, we tested the hypothesis that some cases of myocardial fibrosis in the absence of identifiable causes (primary myocardial fibrosis [PMF]) are associated with genetic variants.

METHODS

Tissue was obtained at autopsy from 4031 consecutive individuals with sudden cardiac death in Northern Finland, among whom PMF was the only structural finding in 145 subjects with sudden cardiac death. We performed targeted next-generation sequencing using a panel of 174 genes associated with myocardial structure and ion channel function when autopsies did not identify a secondary basis for myocardial fibrosis. All variants with an effect on protein and with a minor allele frequency <0.01 were classified as pathogenic or variants of uncertain significance on the basis of American College of Medical Genetics consensus guidelines.

RESULTS

Among the 96 specimens with DNA passing quality control (66%), postmortem genetic tests identified 24 variants of known or uncertain significance in 26 subjects (27%). Ten were pathogenic/likely pathogenic variants in 10 subjects (10%), and 14 were variants of uncertain significance in 11 genes among 16 subjects (17%). Five variants were in genes associated with arrhythmogenic right ventricular cardiomyopathy, 6 in hypertrophic cardiomyopathy-associated genes, and 11 in dilated cardiomyopathy-associated genes; 2 were not associated with these disorders. Four unique variants of uncertain significance cosegregated among multiple unrelated subjects with PMF. No pathogenic/likely pathogenic variants were detected in ion channel-encoding genes.

CONCLUSIONS

A large proportion of subjects with PMF at autopsy had variants in genes associated with arrhythmogenic right ventricular cardiomyopathy, dilated cardiomyopathy, and hypertrophic cardiomyopathy without autopsy findings of those diseases, suggesting that PMF can be an alternative phenotypic expression of structural disease-associated genetic variants or that risk-associated fibrosis was expressing before the primary disease. These findings have clinical implications for postmortem genetic testing and family risk profiling.

Mitochondrial DNA variation in sudden cardiac death: a population-based study

Cardiomyopathy and cardiac conduction defects are common manifestations of mitochondrial disease. Previous studies suggest that clinically asymptomatic individuals harbouring pathogenic mitochondrial DNA (mtDNA) mutations in the cardiac muscle may have sudden cardiac death (SCD) as the first manifestation of mitochondrial disease. We investigated the contribution of pathogenic mtDNA point mutations and mtDNA haplogroups in cardiac muscle in a cohort of 280 Finnish subjects that had died from non-ischaemic SCD with the median age of death at 59 years and in 537 population controls. We did not find any common or novel pathogenic mutations, but the frequency of haplogroup H1 was higher in the SCD subjects than that in 537 population controls (odds ratio: 1.76, confidence interval 95%: 1.02-3.04). We conclude that, at the population level, pathogenic point mutations in mtDNA do not contribute to non-ischaemic SCD, but natural variation may modify the risk.

New Concepts in Sudden Cardiac Arrest to Address an Intractable Epidemic: JACC State-of-the-Art Review

Sudden cardiac arrest (SCA) is one of the largest causes of mortality globally, with an out-of-hospital survival below 10% despite intense research. This document outlines challenges in addressing the epidemic of SCA, along the framework of respond, understand and predict, and prevent. Response could be improved by technology-assisted orchestration of community responder systems, access to automated external defibrillators, and innovations to match resuscitation resources to victims in place and time. Efforts to understand and predict SCA may be enhanced by refining taxonomy along phenotypical and pathophysiological "axes of risk," extending beyond cardiovascular pathology to identify less heterogeneous cohorts, facilitated by open-data platforms and analytics including machine learning to integrate discoveries across disciplines. Prevention of SCA must integrate these concepts, recognizing that all members of society are stakeholders. Ultimately, solutions to the public health challenge of SCA will require greater awareness, societal debate and focused public policy.

Sudden Cardiac Death: Interface Between Pathophysiology and Epidemiology

The population incidence of sudden cardiac arrest (SCA) and sudden cardiac death have not changed appreciably during the decades of improvement in general outcomes from cardiovascular diseases, but the age, clinical circumstances, and pathophysiologic mechanisms have. The epidemiology and pathophysiology of SCA are linked, in that mechanisms of SCA can be modeled based on substrate and expression characteristics. The goal for the future is to expand pathophysiologic and epidemiologic interactions to achieve strong individual risk prediction, to complement the limits of application of population risk data to individuals.

Defibrillation for Ventricular Fibrillation: A Shocking Update

Cardiac arrest is defined as the termination of cardiac activity associated with loss of consciousness, of spontaneous breathing, and of circulation. Sudden cardiac arrest and sudden cardiac death (SCD) are terms often used interchangeably. Most patients with out-of-hospital cardiac arrest have shown coronary artery disease or symptoms during the hour before the event. Cardiac arrest is potentially reversible by cardiopulmonary resuscitation, defibrillation, cardioversion, cardiac pacing, or treatments targeted at the underlying disease (e.g., acute coronary occlusion). We restrict SCD hereafter to cardiac arrest due to ventricular fibrillation, including rhythms shockable by an automatic external defibrillator (AED), implantable cardioverter-defibrillator (ICD), or wearable cardioverter-defibrillator (WCD). We summarize the state of the art related to defibrillation in treating SCD, including a brief history of the evolution of defibrillation, technical characteristics of modern AEDs, strategies to improve AED access and increase survival, ancillary treatments, and use of ICDs or WCDs.