The Characterization of Violent Deaths Among Asian and Pacific Islander Americans

INTRODUCTION

Health disparities in the Asian and Pacific Islander Americans (APIAs) community have not been well described, unlike non-Hispanic Black and Hispanic communities. However, there has been a rise in violence against the APIA community. This study explores and characterizes violent death by incident (e.g., homicide, suicide), weapon (e.g., firearm, strangulation), and location types among APIAs as they compare with other racial or ethnic groups.

METHODS

We used the National Violent Death Reporting System from 2003 to 2018 to characterize violent deaths among APIA and compared them to all other races. We compared these racial categories in two ways. First, we compared all races as a categorical variable that included six non-Hispanic racial categories including "Other or unspecified" and "two or more races. We then created a binary variable of APIA versus All Other Races for analysis. We explored the incident type of death, substance abuse disorders, mental health history, and gang involvement among other variables. We used Chi-square tests for categorical variables and Mann-Whitney U-tests for continuous variables.

RESULTS

Overall, APIAs had a unique pattern of violent death. APIAs were more likely to commit suicide (71.74%-62.21%, P<0.001) and less likely to die of homicide than other races (17.56%-24.31%, P<0.001). In the cases of homicide, APIAs were more likely to have their deaths precipitated by another crime (40.87% versus 27.87%, P < 0.001). APIAs were more than twice as likely to die of strangulation than other races (39.93%-18.06%, P<0.001). Conversely, APIAs were less likely to die by firearm than other races (29.69-51.51, P<0.001).

CONCLUSIONS

APIAs have a unique pattern of violence based on analysis of data from the National Violent Death Reporting System. Our data reveal a significant difference in the incident, weapon and location type as compared to Americans of other races, which begs further inquiry into the patterns of change in time and factors that contribute to inter-racial differences in death patterns.

Overexpression of VEGFα as a biomarker of endothelial dysfunction in aortic tissue of α-GAL-Tg/KO mice and its upregulation in the serum of patients with Fabry's disease

Introduction

Fabry's disease is an X-linked lysosomal storage disorder caused by reduced activity of α-galactosidase A (GAL), leading to premature death on account of renal, cardiac, and vascular organ failure. Accumulation of the GAL substrate globotriaosylceramide (Gb3) in endothelial and smooth muscle cells is associated with early vascular cell damage, suggesting endothelial dysfunction as a driver of cardiorenal organ failure. Here, we studied the vascular expression of the key angiogenic factors, VEGFα and its antagonist angiostatin, in Fabry α-GAL-Tg/KO mice and determined circulating VEGFα and angiostatin serum levels in patients with Fabry's disease and healthy controls.

Methods

Cryopreserved aortic vessels from six α-GAL-Tg/KO and six wild-type (WT) mice were obtained and VEGFα and angiostatin levels were determined by performing Western blot analysis. VEGFα expression was visualized by an immunohistochemical staining of paraffin aortic rings. In addition, VEGFα and angiostatin serum levels were measured by using an enzyme-linked immunosorbent assay in 48 patients with genetically verified Fabry's disease (50% male) and 22 healthy controls and correlated with disease severity markers such as lyso-Gb3, albuminuria, NTproBNP, high-sensitive troponin T (hsTNT), and myocardial wall thickness.

Results

It was found that there was a significant increase in VEGFα protein expression (1.66 ± 0.35 vs. 0.62 ± 0.16, p = 0.0009) and a decrease in angiostatin expression (0.024 ± 0.007 vs. 0.053 ± 0.02, p = 0.038) in aortic lysates from α-GAL-Tg/KO compared with that from WT mice. Immunohistochemical staining revealed an adventitial VEGFα signal in α-GAL-Tg/KO mice, whereas no VEGFα signal could be detected in WT mice aortas. No differences in aortic angiostatin expression between α-GAL-Tg/KO- and WT mice could be visualized. The serum levels of VEGFα were significantly upregulated in patients with Fabry's disease compared with that in healthy controls (708.5 ± 426.3 vs. 458.5 ± 181.5 pg/ml, p = 0.048) and positively associated with albuminuria (r = 0.82, p < 0.0001) and elevated NTproBNP (r = 0.87, p < 0.0001) and hsTNT values (r = 0.41, p = 0.048) in male patients with Fabry's disease. For angiostatin, no significant difference was found between patients with Fabry's disease and healthy controls (747.6 ± 390.3 vs. 858.8 ± 599.3 pg/ml).

Discussion

In conclusion, an overexpression of VEGFα and downregulation of its counter player angiostatin in aortic tissue of α-GAL-Tg/KO mice support the hypothesis of an underlying vasculopathy in Fabry's disease. Elevated VEGFα serum levels were also observed in patients with Fabry's disease and were positively associated with elevated markers of organ manifestation in males. These findings suggest that angiogenetic markers, such as VEGFα, may be potentially useful biomarkers for the detection of endothelial dysfunction in classical Fabry's disease.

Prevalence and pattern of focal and potential diffuse myocardial fibrosis in male and female marathon runners using contrast-enhanced cardiac magnetic resonance

OBJECTIVES

This study analyzed the prevalence and pattern of focal and potential diffuse myocardial fibrosis detected by late gadolinium enhancement (LGE) and extracellular volume (ECV) imaging in male and female marathon runners using cardiac magnetic resonance (CMR).

METHODS

Seventy-four marathon runners were studied including 55 males (44 ± 8 years) and 19 females (36 ± 7 years) and compared to 36 controls with similar age and sex using contrast-enhanced CMR, exercise testing, and blood samples.

RESULTS

Contrast-enhanced CMR revealed focal myocardial fibrosis in 8 of 74 runners (11%). The majority of runners were male (7 of 8, 88%). LGE was typically non-ischemic in 7 of 8 runners (88%) and ischemic in one runner. ECV was higher in remote myocardium without LGE in male runners (25.5 ± 2.3%) compared to male controls (24.0 ± 3.0%, p < 0.05), indicating the potential presence of diffuse myocardial fibrosis. LV mass was higher in LGE + males (86 ± 18 g/m2) compared to LGE- males (73 ± 14 g/m2, p < 0.05). Furthermore, LGE + males had lower weight (69 ± 9 vs 77 ± 9 kg, p < 0.05) and shorter best marathon finishing times (3.2 ± 0.3 h) compared to LGE- males (3.6 ± 0.4 h, p < 0.05) suggesting higher training load in these runners to accomplish the marathon in a short time.

CONCLUSION

The high frequency of non-ischemic myocardial fibrosis in LGE + male runners can be related to increased LV mass in these runners. Furthermore, a higher training load could explain the higher LV mass and could be one additional cofactor in the genesis of myocardial fibrosis in marathon runners.

KEY POINTS

• A high frequency of myocardial fibrosis was found in marathon runners. • Myocardial fibrosis occurred typically in male runners and was typically non-ischemic. • Higher training load could be one cofactor in the genesis of myocardial fibrosis in marathon runners.

Comparison of classical Fabry and its p.D313Y and p.A143T variants by cardiac T1 mapping, LGE and feature tracking myocardial strain

Cardiac manifestation of classical Fabry disease (cFD) varies with sex and presence of left ventricular hypertrophy. p.D313Y/p.A143T variants (vFD) represent milder late-onset phenotypes, however, data on vFD are scarce. Patients with FD (cFD = 37;vFD = 14) and 14 healthy controls underwent 1.5 T CMR including Cine, LGE, native T1 mapping(nT1) and myocardial strain(CMR-FT). CMR-FT was assessed using ventricular longitudinal, circumferential, radial (LV-GLS/RV-GLS, LV-GCS/LV-GRS), and atrial longitudinal strain (LA/RA_Total, LA/RA_Conduit, LA/RA_Booster). In cFD reduced myocardial strain (LV-GLS: -20 ± 4 vs. -24 ± 3%,p = 0.007; LV-GCS: -20 ± 4 vs. -26 ± 4%,p = 0.002, LA _Total -GLS: 29 ± 10 vs. 37 ± 6%,p = 0.007; LA _Conduit -GLS: 15 ± 10 vs. 23 ± 5%,p = 0.003) and nT1 values (951 ± 51 ms vs. 1036 ± 20 ms, p < 0.001) were observed compared to controls. In vFD findings were comparable to controls. LV-GCS provided the closest Area under the curve (AUC) to nT1 (0.84 vs. 0.92, p > 0.05) for discrimination of cFD versus controls. Significantly lower LV-GLS/LV-GCS was found in male compared to female cFD (-19 ± 4 vs. -22 ± 4%, p = 0.03). In six non-hypertrophied female cFD with normal nT1 LA_Total -GLS was the only discriminating parameter with an accuracy of 86%. LV-GLS, LV-GCS and LA_Total -GLS can detect impaired cardiac mechanics of cFD besides nT1. LA_Total -GLS might identify non-hypertrophied female cFD. Variants p.D313Y/p.A143T did not reveal cardiac involvement by multiparametric CMR.

Hereditary transthyretin-related amyloidosis is frequent in polyneuropathy and cardiomyopathy of no obvious aetiology

BACKGROUND

Hereditary Transthyretin-Related Amyloidosis, a clinically heterogeneous autosomal dominant disease caused by pathogenic variants in the TTR gene, is characterized by the deposition of insoluble misfolded protein fibrils. The diagnosis, especially in non-endemic areas, is typically delayed by 4-5 years; a misdiagnosis due to clinical heterogeneity is common. The study objective was to define the prevalence of Hereditary Transthyretin-Related Amyloidosis in patients with polyneuropathy and/or cardiomyopathy of no obvious aetiology.

METHOD

A multicenter observational "Epidemiological analysis for the hereditary Transthyretin-Related AMyloidosis"-TRAM study was performed in Germany, Austria, and Switzerland.

RESULTS

A total of 5141 participants were recruited by 50 neurologic and 27 cardiologic specialized centres. Genetic analysis demonstrated a 1.1% Hereditary Transthyretin-Related Amyloidosis positivity rate among patients with polyneuropathy and/or cardiomyopathy of not obvious aetiology. Twenty-one various TTR variants (TTR-positive) were identified. Body Mass Index was lower in the TTR-positive patients as an indicator for the involvement of the autonomic nervous system; the age of onset of clinical manifestations was higher in TTR-positive patients. There were no other genotype-phenotype correlations or the prevalence of specific clinical manifestations in TTR-positive patients.

CONCLUSIONS

Our data support the fact that Hereditary Transthyretin-Related Amyloidosis is underdiagnosed in polyneuropathy and cardiomyopathy patients. Routine implementation of genetic testing is recommended in patients with unexplained polyneuropathy and/or cardiomyopathy to accelerate the earlier diagnosis and the time-sensitive treatment initiation.KEY MESSAGESMore than 5.000 participants with CM and/or PNP of no obvious aetiology were recruited in the observational "Epidemiological analysis for the hereditary Transthyretin-Related AMyloidosis" TRAM study and screened for pathogenic TTR variants.The study demonstrated >1% of patients with CM and/or PNP of unclear aetiology are positive for a pathogenic TTR variant.Routine genetic testing is recommended in patients with unexplained CM and/or PNP to accelerate the initial diagnosis and timely treatment initiation.

Circumstances of Suicide Among Lesbian, Gay, Bisexual and Transgender Individuals

INTRODUCTION

Suicide rates for sexual minorities are higher than the heterosexual population. The purpose of this study is to explore circumstances surrounding suicide completion to inform future intervention strategies for suicide among lesbian, gay, bisexual and transgender (LGBT) individuals.

MATERIALS AND METHODS

We completed a retrospective analysis of data from the National Violent Death Reporting System (NVDRS) from 2013-2017. Victims identified as transgender were considered separately. We stratified analysis by identified sex of the victim for the LGB population.

RESULTS

Of the 16,831 victims whose sexual orientation or transgender status was known: 3886 (23.1%) were identified as female, 12,945 (76.9%) were identified as male. 479 (2.8%) were identified as LGBT; of these, 53 (11%) were transgender. LGBT victims were younger than non-LGBT victims. Male LGB victims were more likely to have a history of prior suicide attempts, past or current mental illness diagnosis, and were less likely to use firearms than male heterosexual victims. Female LGB victims were more likely to have problems in an intimate partner relationship than heterosexual women, while LGB men were more likely to have problems in family or other relationships. Transgender victims were again more likely to have mental health problems and a history of prior attempts, but less likely to have intimate partner problems and more likely to have a history of child abuse.

CONCLUSIONS

These results highlight the importance of promoting suicide interventions that recognize the complex intersection between stated gender, sex, and sexuality and the different cultural impacts these identities can have.

A Novel miRNA Screen Identifies miRNA-4454 as a Candidate Biomarker for Ventricular Fibrosis in Patients with Hypertrophic Cardiomyopathy

(1) Background: Left ventricular hypertrophy, myocardial disarray and interstitial fibrosis are the hallmarks of hypertrophic cardiomyopathy (HCM). Access to the myocardium for diagnostic purposes is limited. Circulating biomolecules reflecting the myocardial disease processes could improve the early detection of HCM. Circulating miRNAs have been found to reflect disease processes in several cardiovascular diseases. (2) Methods: We quantified circulating miRNA molecules in the plasma of 24 HCM and 11 healthy controls using the Human v3 miRNA Expression Assay Kit Code set (Nanostring Tech., Seattle, WA, USA) and validated differentially expressed miRNAs using RT-PCR. (3) Results: In comparison to healthy controls, the levels of six miRNAs (miR-1, miR-3144, miR-4454, miR-495-3p, miR-499a-5p and miR-627-3p) were higher in the plasma of HCM patients than healthy individuals (p < 0.05). Of these, higher levels of miR-1, miR-495 and miR-4454 could be validated by real-time PCR. In addition, elevated miR-4454 levels were significantly correlated with cardiac fibrosis, detected by magnetic resonance imaging in HCM patients. (4) Conclusions: Circulating miR-1, miR-495-3p and miR-4454 levels are elevated in the plasma of HCM patients. To the best of our knowledge, this is the first report showing a correlation between miR-4454 levels and cardiac fibrosis in HCM. This suggests miR-4454 as a potential biomarker for fibrosis in these patients.

Treatment of fabry disease with migalastat-outcome from a prospective 24 months observational multicenter study (FAMOUS)

AIMS

Fabry disease (FD) is an X-linked lysosomal storage disorder caused by a deficiency of the lysosomal enzyme α-galactosidase A (GLA/AGAL) resulting in lysosomal accumulation of globotriaosylceramide (Gb3). Patients with amenable GLA mutations can be treated with migalastat, an oral pharmacologic chaperone increasing endogenous AGAL activity. In this prospective observational multicenter study safety as well as cardiovascular, renal, and patient-reported outcomes and disease biomarkers were assessed after 12 and 24 months of migalastat treatment under "real world" conditions.

METHODS AND RESULTS

54 patients (26 females) (33 of these [61.1%] pre-treated with enzyme replacement therapy) with amenable mutations were analyzed. Treatment was generally safe and well tolerated. 153 events per 1,000 patient-years were detected. Overall left ventricular mass index decreased after 24 months (all: -7.5 ± 17.4 g/m2, p = 0.0118; females: -4.6 ± 9.1 g/m2, p = 0.0554; males: -9.9 ± 22.2 g/m2, p = 0.0699). After 24 months, females and males presented with a moderate yearly loss of eGFR (-2.6 and -4.4 ml/min/1.73 m2 per year; p = 0.0317 and p = 0.0028, respectively). FD-specific manifestations/symptoms remained stable (all p > 0.05). 76.9% of females and 50% of males suffered from pain, which has not improved under treatment. FD-specific disease scores (DS3 and MSSI) remained stable during treatment. AGAL activities and plasma lyso-Gb3 values remained stable, although some male patients presented with increasing lyso-Gb3 levels over time.

CONCLUSIONS

Treatment with migalastat was generally safe and resulted in most patients in an amelioration of left ventricular mass. However, due to the heterogeneity of FD phenotypes, it is advisable that the treating physician monitors the clinical response regularly.

Ablation of Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy: Treatment Strategy, Characteristics of Consecutive Atrial Tachycardia and Long-Term Outcome

Background

Atrial fibrillation (AF) is common in patients with hypertrophic cardiomyopathy (HCM) and is associated with a deterioration of clinical status. Ablation of symptomatic AF is an established therapy, but in HCM, the characteristics of recurrent atrial arrhythmias and the long‐term outcome are uncertain.

Methods and Results

Sixty‐five patients with HCM (aged 64.5±9.9 years, 42 [64.6%] men) underwent AF ablation. The ablation strategy included pulmonary vein isolation in all patients and ablation of complex fractionated atrial electrograms or subsequent atrial tachycardias (AT) if appropriate. Paroxysmal, persistent AF, and a primary AT was present in 13 (20.0%), 51 (78.5%), and 1 (1.5%) patients, respectively. Twenty‐five (38.4%) patients developed AT with a total number of 54 ATs. Stable AT was observed in 15 (23.1%) and unstable AT in 10 (15.3%) patients. The mechanism was characterized as a macroreentry in 37 (68.5%), as a localized reentry in 12 (22.2%), a focal mechanism in 1 (1.9%), and not classified in 4 (7.4%) ATs. After 1.9±1.2 ablation procedures and a follow‐up of 48.1±32.5 months, freedom of AF/AT recurrences was demonstrated in 60.0% of patients. No recurrences occurred in 84.6% and 52.9% of patients with paroxysmal and persistent AF, respectively (P<0.01). Antiarrhythmic drug therapy was maintained in 24 (36.9%) patients.

Conclusions

AF ablation in patients with HCM is effective for long‐term rhythm control, and especially patients with paroxysmal AF undergoing pulmonary vein isolation have a good clinical outcome. ATs after AF ablation are frequently observed in HCM. Freedom of atrial arrhythmia is achieved by persistent AF ablation in a reasonable number of patients even though the use of antiarrhythmic drug therapy remains high.

Clinical characteristics and myocardial function assessed by traditional and novel echocardiographic methods in competitive triathletes with and without myocardial fibrosis

Background

The aim of the present study was to compare clinical characteristics and cardiac structure and function in competitive triathletes with and without myocardial fibrosis.

Methods

Cardiac fibrosis in 61 healthy male competitive triathletes (&gt;10 hrs of training per week, age 45±10 yrs) was quantified using LGE-sequences in CMR (1.5 tesla scanner).

Transthoracic echocardiography, physical examination, past medical history and routine lab diagnosis for exclusion of other conditions were performed.

Baseline characteristics like blood pressure at rest (BP), bodymass-index (BMI), and systolic and diastolic echocardiographic parameters (left atrial volume index (LAVI), e', E, A, right ventricular pressure gradient) as well as global longitudinal strain, were analysed by two independent observers blinded to the CMR measurements. Triathletes were sub-divided into LGE-positives (LGE+) vs. LGE-negatives (LGE-).

Results

All individuals appeared healthy with no drug history. Focal non-ischaemic LGE was detected in 19 triathletes. Compared to LGE-negative triathletes, LGE-positives showed significantly higher systolic BP (142 vs. 128 mmHg, p=0.004). Logistic regression showed, that per 10 mmHg enhanced blood pressure the chance for LGE rises by 89%. Triathletes with and without LGE demonstrated no difference in conventional echocardiographic measurements such as left ventricular ejection fraction and volumes and no difference in diastolic parameters. But the presence of MF did mediate global longitudinal strain (GLS).

Global longitudinal strain was significantly reduced in LGE positive athletes (LGE+: −19.8±3.4; LGE-: −21.7±2.4, p=0.04)

Conclusions

Reduced global longitudinal strain mediated as an early echocardiographic marker for subclinical changes in asymptomatic competitive triathletes with myocardial fibrosis compared to triathletes without LGE. Novel echocardiographic parameter such as longitudinal strain might serve as an easy tool to identify high endurance athletes at higher risk for cardiovascular events and that individuals with enhanced blood pressure should undergo cardiac consultation before starting endurance-training in competitive disciplines.

Funding Acknowledgement

Type of funding source: None

Treatment of Fabry's Disease With Migalastat: Outcome From a Prospective Observational Multicenter Study (FAMOUS)

Fabry's disease (FD) is an X-linked lysosomal storage disorder caused by the deficient activity of the lysosomal enzyme α-galactosidase A (α-Gal A) leading to intracellular accumulation of globotriaosylceramide (Gb3). Patients with amenable mutations can be treated with migalastat, a recently approved oral pharmacologic chaperone to increase endogenous α-Gal A activity. We assessed safety along with cardiovascular, renal, and patient-reported outcomes and disease biomarkers in a prospective observational multicenter study after 12 months of migalastat treatment under "real-world" conditions. Fifty-nine (28 females) patients (34 (57.6%) pretreated with enzyme replacement therapy) with amenable mutations were recruited. Migalastat was generally safe and well tolerated. Females and males presented with a reduction of left ventricular mass index (primary end point) (-7.2 and -13.7 g/m² , P = 0.0050 and P = 0.0061). FD-specific manifestations and symptoms remained stable (all P > 0.05). Both sexes presented with a reduction of estimated glomerular filtration rate (secondary end point) (-6.9 and -5.0 mL/minute/1.73 m² ; P = 0.0020 and P = 0.0004, respectively), which was most prominent in patients with low blood pressure (P = 0.0271). α-Gal A activity increased in male patients by 15% from 29% to 44% of the normal wild-type activity (P = 0.0106) and plasma lyso-Gb3 levels were stable in females and males (P = 0.3490 and P = 0.2009). Reevaluation of mutations with poor biochemical response revealed no marked activity increase in a zero activity background. We conclude that therapy with migalastat was generally safe and resulted in an amelioration of left ventricular mass. In terms of impaired renal function, blood pressure control seems to be an unattended important goal.

Disease modeling of a mutation in α-actinin 2 guides clinical therapy in hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a cardiac genetic disease accompanied by structural and contractile alterations. We identified a rare c.740C>T (p.T247M) mutation in ACTN2, encoding α-actinin 2 in a HCM patient, who presented with left ventricular hypertrophy, outflow tract obstruction, and atrial fibrillation. We generated patient-derived human-induced pluripotent stem cells (hiPSCs) and show that hiPSC-derived cardiomyocytes and engineered heart tissues recapitulated several hallmarks of HCM, such as hypertrophy, myofibrillar disarray, hypercontractility, impaired relaxation, and higher myofilament Ca²⁺ sensitivity, and also prolonged action potential duration and enhanced L-type Ca²⁺ current. The L-type Ca²⁺ channel blocker diltiazem reduced force amplitude, relaxation, and action potential duration to a greater extent in HCM than in isogenic control. We translated our findings to patient care and showed that diltiazem application ameliorated the prolonged QTc interval in HCM-affected son and sister of the index patient. These data provide evidence for this ACTN2 mutation to be disease-causing in cardiomyocytes, guiding clinical therapy in this HCM family. This study may serve as a proof-of-principle for the use of hiPSC for personalized treatment of cardiomyopathies.

P3778Long-term outcome of non-pharmacologial treatment of atrial fibrillation in hypertrophic cardiomyopathy: a large single-centre experience

Introduction

Atrial fibrillation (AF) is common in hypertrophic cardiomyopathy (HCM) and is generally associated with a significant deterioration of clinical status. Non-pharmacological treatment such as surgical and catheter ablation has become an established therapy for symptomatic AF but in patients with HCM often having a chronically increased left atrial pressure and extensive atrial cardiomyopathy the long-term outcome is uncertain.

Purpose

The present study aimed to analyse the long-term outcome of AF ablation in HCM and the mechanism of recurrent atrial arrhythmias using high-density mapping systems.

Methods

A total of 65 patients (age 64.5±9.9 years, 42 (64.6%) male) with HCM undergoing AF ablation for symptomatic AF were included in our study. The ablation strategy for catheter ablation included pulmonary vein isolation in all patients and biatrial ablation of complex fractionated electrograms with additional ablation lines if appropriate. In patients with suspected atrial tachycardia (AT) high-density activation and substrate mapping were performed. A surgical ablation at the time of an operative myectomy for left ventricular outflow tract obstruction was performed in 8 (12.3%) patients. The outcome was analysed using clinical assessment, Holter ECG and continuous rhythm monitoring of cardiac implantable electric devices.

Results

Paroxysmal AF was present in 27 (41.6%), persistent AF in 37 (56.9%) and primary AT in 1 (1.5%) patients. The mean left atrial diameter was 54.1±12.5 ml. In 11 (16.9%) patients with AT high-density mapping was used to characterize the mechanism of the ongoing tachycardia. After 1.9±1.2 ablation procedures and a follow-up of 48.5±37.2 months, ablation success was demonstrated in 58.9% of patients. The success rate for paroxysmal and persistent AF was 70.0% and 55.8%, respectively (p=0.023). Of those patients with AT high-density mapping guided ablation was successful in 44.4% of patients. The LA diameter of patients with a successful ablation was smaller (52.2 vs. 58.1 mm; p=0.003).

Conclusion

Non-pharmacological treatment of AF in HCM is effective during long-term follow-up. Paroxysmal AF and a smaller LA diameter are favourable for successful ablation. In patients with complex AT the use of high-density mapping can guide ablation resulting in further ablation success in a reasonable number of patients.

P1692Cardiac fibrosis in competitive triathletes is associated with arterial hypertension

Background

Myocardial fibrosis is an occasional finding in asymptomatic athletes.

Purpose

Evaluation of clinical conditions with possible impact on cardiac fibrosis in competitive triathletes.

Methods

Cardiac fibrosis in 61 male competitive triathletes (>10 hrs of training per week, mean 45 yrs) and 19 controls (mean 38 yrs), was quantified using late gadolinium enhancement (LGE) in cardiac magnet-resonance imaging (CMR). Physical examination, past medical history, and routine lab diagnosis were performed and baseline characteristics like blood pressure at rest (BP), body mass index (BMI), and echocardiographic parameters were measured. Triathletes were sub-divided into LGE positives vs. negatives.

Results

All individuals appeared healthy with no drug history of note and a normal cardiac function according to echocardiography. Focal non-ischaemic LGE was detected in 18 triathletes (5.2±4.5 g; 3.5±2.8 g/m2) and none of the controls. Compared to LGE negative triathletes, LGE positives showed significantly higher systolic BP and BMI (see Table). 67% of the LGE positives and only 14% of the LGE negative athletes showed first degree arterial hypertension and 56% of the LGE positives vs. 21% of the LGE negatives were formally overweight (BMI≥25 kg/m2). Controls had smaller left atrial volume indices than the triathletes, in line with characteristics of the athlete's heart. The triathletes were older than the controls (see Table below), but had a normal diastolic function. 38% of the controls and 31% of all triathletes were overweight. Equally to the LGE negatives, 14% of the controls were hypertensive.

Clinical parameters Athletes LGE+ LGE− Controls p-value (athletes vs. controls) p-value (LGE+ vs. LGE−) p-value (LGE− vs. controls) n 61 18 43 19 Age (yrs) 44.6±9.80 48.2±9.04 42.2±9.96 38.4±11.12 0.0371* 0.1222 0.0016* BMI (kg/m2) 24.1±2.57 25.3±2.75 23.8±2.4 24.5±2.74 0.2564 0.0315* 0.1228 Sys. BP (mmHg) 132±15.80 144±17.52 128±12.99 124±15.93 0.0145* 0.0020* 0.2426 LAVI (ml/m2) 29.13±6.79 31.45±8.02 26.68±6.26 24.25±5.48 0.0014* 0.4389 0.0053* All values shown as mean values with standard deviation, if not otherwise indicated, BMI = body mass index, LAVI = left atrial volume index, athletes = all triathletes; LGE+ = triathletes with cardiac LGE visualised by CMR, LGE− = triathletes without LGE in CMR. *Significant p-value, vs. = versus, Sys. BP = systolic blood pressure.

Conclusion

In competitive triathletes, there is a significant correlation between cardiac fibrosis and arterial hypertension at rest as well as overweight. We therefore recommend, that individuals with these characteristics should undergo cardiac consultation before starting endurance-training in competitive disciplines.

Acute impact of an endurance race on cardiac function and biomarkers of myocardial injury in triathletes with and without myocardial fibrosis

AIMS

The aim of this study was to investigate the occurrence of myocardial injury and cardiac dysfunction after an endurance race by biomarkers and cardiac magnetic resonance in triathletes with and without myocardial fibrosis.

METHODS AND RESULTS

Thirty asymptomatic male triathletes (45 ± 10 years) with over 10 training hours per week and 55 ± 8 ml/kg per minute maximal oxygen uptake during exercise testing were studied before (baseline) and 2.4 ± 1.1 hours post-race. Baseline cardiac magnetic resonance included cine, T1/T2, late gadolinium enhancement (LGE) and extracellular volume imaging. Post-race non-contrast cardiac magnetic resonance included cine and T1/T2 mapping. Non-ischaemic myocardial fibrosis was present in 10 triathletes (LGE+) whereas 20 had no fibrosis (LGE-). At baseline, LGE + triathletes had higher peak exercise systolic blood pressure with 222 ± 21 mmHg compared to LGE- triathletes (192 ± 30 mmHg, P < 0.01). Post-race troponin T and creatine kinase MB were similarly increased in both groups, but there was no change in T2 and T1 from baseline to post-race with 54 ± 3 ms versus 53 ± 3 ms (P = 0.797) and 989 ± 21 ms versus 989 ± 28 ms (P = 0.926), respectively. However, post-race left atrial ejection fraction was significantly lower in LGE + triathletes compared to LGE- triathletes (53 ± 6% vs. 59 ± 6%, P < 0.05). Furthermore, baseline atrial peak filling rates were lower in LGE -  triathletes (121 ± 30 ml/s/m²) compared to LGE + triathletes (161 ± 34 ml/s/m², P < 0.01). Post-race atrial peak filling rates increased in LGE- triathletes to 163 ± 46 ml/s/m², P < 0.001), but not in LGE + triathletes (169 ± 50ml/s/m², P = 0.747).

CONCLUSION

Despite post-race troponin T release, we did not find detectable myocardial oedema by cardiac magnetic resonance. However, the unfavourable blood pressure response during exercise testing seemed to be associated with post-race cardiac dysfunction, which could explain the occurrence of myocardial fibrosis in triathletes.

Impact of Myocardial Fibrosis on Left Ventricular Function Evaluated by Feature-Tracking Myocardial Strain Cardiac Magnetic Resonance in Competitive Male Triathletes With Normal Ejection Fraction

BACKGROUND

To analyze the effect of myocardial fibrosis on left ventricular (LV) function evaluated by feature-tracking strain analysis by cine cardiac magnetic resonance (CMR) in competitive male triathletes with normal ejection fraction (EF).Methods and Results:78 asymptomatic male triathletes with >10 weekly training hours (43±11 years) and 28 male age-matched controls were studied by late gadolinium enhancement (LGE) and cine CMR. Global and segmental radial, longitudinal and circumferential strains were analyzed using feature-tracking cine CMR. Focal non-ischemic LGE was observed in 15 of 78 triathletes (19%, LGE+) with predominance in the basal inferolateral segments. LVEF was normal in LGE+ (62±6%) and LGE- triathletes (62±5%, P=0.958). In contrast, global radial strain was lower in LGE+ triathletes at 40±7% compared with LGE- triathletes (45±7%, P<0.05). Reduced segmental radial strain occurred either in LGE+ segments or in directly adjacent segments. Strain analysis revealed regional differences in controls, with the highest radial and longitudinal strain in the inferolateral segments, which were typically affected by fibrosis in LGE+ triathletes.

CONCLUSIONS

Reduced global and regional radial strain suggests a negative effect of myocardial fibrosis on LV function in LGE+ triathletes with normal EF. The observed regional differences in controls with the highest radial and longitudinal strain in the inferolateral segments may explain the typical occurrence of fibrosis in this myocardial region in triathletes.

Efficacy of Ranolazine in Patients With Symptomatic Hypertrophic Cardiomyopathy: The RESTYLE-HCM Randomized, Double-Blind, Placebo-Controlled Study

BACKGROUND

The late sodium current inhibitor ranolazine reverses the main electrophysiological and mechanical abnormalities of human hypertrophic cardiomyopathy (HCM) cardiomyocytes in vitro, suggesting potential clinical benefit. We aimed to assess the effect of ranolazine on functional capacity, symptomatic status, diastolic function, and arrhythmias in HCM.

METHODS AND RESULTS

In this multicenter, double-blind, phase 2 study, 80 adult patients with nonobstructive HCM (age 53±14 years, 34 women) were randomly assigned to placebo (n=40) or ranolazine 1000 mg bid (n=40) for 5 months. The primary end point was change in peak VO₂ compared with baseline using cardiopulmonary exercise test. Echocardiographic lateral and septal E/E' ratio, prohormone brain natriuretic peptide levels, 24-hour Holter arrhythmic profile, and quality of life were assessed. Ranolazine was safe and well tolerated. Overall, there was no significant difference in VO₂ peak change at 5 months in the ranolazine versus placebo group (delta 0.15±3.96 versus -0.02±4.25 mL/kg per minute; P=0.832). Ranolazine treatment was associated with a reduction in 24-hour burden of premature ventricular complexes compared with placebo (>50% reduction versus baseline in 61% versus 31%, respectively; P=0.042). However, changes in prohormone brain natriuretic peptide levels did not differ in the ranolazine compared with the placebo group (geometric mean median [interquartile range], -3 pg/mL [-107, 142 pg/mL] versus 78 pg/mL [-71, 242 pg/mL]; P=0.251). Furthermore, E/E' ratio and quality of life scores showed no significant difference.

CONCLUSIONS

In patients with nonobstructive HCM, ranolazine showed no overall effect on exercise performance, plasma prohormone brain natriuretic peptide levels, diastolic function, or quality of life. The drug showed an excellent safety profile and was associated with reduced premature ventricular complex burden. Late sodium current inhibition does not seem to improve functional capacity in HCM.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrialsregister.eu. Unique identifier: 2011-004507-20.

Serum Biomarkers of Endothelial Dysfunction in Fabry Associated Cardiomyopathy

Background: Fabry disease (FD) is characterized by early development of vasculopathy and endothelial dysfunction. However, it is unclear whether these findings also play a pivotal role in cardiac manifestation. As Fabry cardiomyopathy (FC) is the leading cause of death in FD, we aimed to gather a better insight in pathological mechanisms of the disease.

Methods: Serum samples were obtained from 17 healthy controls, 15 FD patients with and 7 without FC. FC was defined by LV wall thickening of >12 mm in cardiac magnetic resonance imaging and serum level of proBNP, high sensitive Troponin T (hsT), and globotriaosylsphingosine (lyso-GB3) were obtained. A multiplex ELISA-Assay for 23 different angiogenesis markers was performed in pooled samples. Markers showing significant differences among groups were further analyzed in single samples using specific Elisa antibody assays. L-homoarginine (hArg), L-arginine, asymmetric (ADMA), and symmetric Dimethylarginine (SDMA) were quantified by liquid chromatography—mass spectrometry.

Results: Angiostatin and matrix metalloproteinase 9 (MMP-9) were elevated in FD patients compared to controls independently of the presence of FC (angiostatin: 98 ± 25 vs. 75 ± 15 ng/mL; p = 0.001; MMP-9: 8.0 ± 3.4 vs. 5.0 ± 2.4 μg/mL; p = 0.002). SDMA concentrations were highest in patients with FC (0.90 ± 0.64 μmol/l) compared to patients without (0.57 ± 0.10 μmol/l; p = 0.027) and vs. controls (0.58 ± 0.12 μmol/l; p = 0.006) and was positively correlated with indexed LV-mass (r = 0.61; p = 0.003), hsT (r = 0.56, p = 0.008), and lyso-Gb3 (r = 0.53, p = 0.013). Accordingly, the ratio of L-homoarginine to SDMA (hArg/SDMA) was lowest in patients with FC (2.63 ± 1.78) compared to controls (4.16 ± 1.44; p = 0.005). For L-arginine, hArg and ADMA no significant differences among groups could be detected, although a trend toward higher ADMA and lower hArg levels could be observed in the FC group. Furthermore, a significant relationship between kidney and cardiac function could be revealed (p = 0.045).

Conclusion: Elevated MMP-9 and angiostatin levels suggest an increased extracellular matrix turnover in FD patients. Furthermore, endothelial dysfunction may also be involved in FC, as SDMA and hArg/SDMA are altered in these patients.

Atrial Fibrillation in Hypertrophic Cardiomyopathy: Diagnosis and Considerations for Management

Atrial fibrillation is common in hypertrophic cardiomyopathy with a prevalence of 22-32 %. The impact of atrial fibrillation on overall survival, left ventricular function, thromboembolic stroke and quality of life is crucial. This review enlightens incidence, pathophysiology, and clinical symptoms. Early recognition of atrial fibrillation is essential. Monitoring methods for early detection are described. Finally effective therapy options are discussed including oral anticoagulation and the role of interventional catheter-based ablation in the treatment of atrial fibrillation in HCM patients.

Myocardial Fibrosis in Competitive Triathletes Detected by Contrast-Enhanced CMR Correlates With Exercise-Induced Hypertension and Competition History

OBJECTIVES

This study analyzed the presence of myocardial fibrosis detected by late gadolinium-enhancement (LGE) cardiac magnetic resonance (CMR) in correlation with the performance of competitive triathletes objectified by an exercise test and individual competition history.

BACKGROUND

Myocardial fibrosis detected by LGE CMR has been reported to occur in 0% to 50% of asymptomatic athletes. However, the cause and mechanisms of myocardial fibrosis are unclear.

METHODS

Eighty-three asymptomatic triathletes undergoing >10 training h per week (43 ± 10 years of age; 65% male) and 36 sedentary controls were studied by using LGE and extracellular volume (ECV) CMR. Parameters of physical fitness were measured by spiroergometry. Triathletes reported their lifetime competition results.

RESULTS

LGE CMR revealed focal nonischemic myocardial fibrosis in 9 of 54 (17%) male triathletes (LGE⁺) but in none of the female triathletes (p < 0.05). LGE⁺ triathletes had higher peak exercise systolic blood pressure (213 ± 24 mm Hg) than LGE^- triathletes (194 ± 26 mm Hg; p < 0.05). Furthermore, left ventricular mass index was higher in LGE⁺ triathletes (93 ± 7 g/m²) than in LGE^- triathletes (84 ± 11 g/m²; p < 0.05). ECV in LGE^- myocardium was higher in LGE⁺ triathletes (26.3 ± 1.8%) than in LGE^- triathletes (24.4 ± 2.2%; p < 0.05). LGE⁺ triathletes completed longer cumulative distances in swimming and cycling races and participated more often in middle and Iron Man distances than LGE^- triathletes. A cycling race distance of >1,880 km completed during competition had the highest accuracy to predict LGE, with an area under the curve value of 0.876 (p < 0.0001), resulting in high sensitivity (89%) and specificity (79%). Multivariate analysis identified peak exercise systolic blood pressure (p < 0.05) and the swimming race distance (p < 0.01) as independent predictors of LGE presence.

CONCLUSIONS

Myocardial fibrosis in asymptomatic triathletes seems to be associated with exercise-induced hypertension and the race distances. There appears to be a safe upper limit, beyond which exercise may result in myocardial fibrosis.

The T-peak-to-T-end interval: a novel ECG marker for ventricular arrhythmia and appropriate ICD therapy in patients with hypertrophic cardiomyopathy

INTRODUCTION

Hypertrophic cardiomyopathy (HCM) is associated with an increased risk of sudden cardiac death (SCD) primarily due to ventricular arrhythmia (VA). In patients (pts.) with a high risk of SCD, the implantation of an intracardiac cardioverter defibrillator (ICD) is thus indicated. Previous studies suggest that a prolonged interval between the peak and the end of the T wave, T-peak to T-end (TpTe), is associated with an elevated risk of VA and SCD in various clinical settings. The aim of our study was to evaluate the association between TpTe and VA in HCM pts. with a previously implanted ICD.

METHODS

In 40 HCM pts. (51.4 ± 16.4 years; 62.5% men), TpTe was measured using the baseline digital standard resting 12-lead ECG during sinus rhythm. VA was assessed by device follow-up.

RESULTS

Within 41.8 ± 35.1 months, 7 (17.5%) pts. had VA leading to appropriate therapy (AT), 7 pts. (17.5%) had non-sustained VA, and 26 pts. (65.0%) had no VA. The maximum TpTe was significantly prolonged in pts. with VA leading to AT compared to pts. without VA (101.3 ± 19.6 vs. 79.9 ± 15.3 ms; p = 0.004). Maximum TpTe was associated with an elevated risk of VA leading to AT (hazard ratio per 10 ms increase 1.63; 95% CI 1.04-2.54; p = 0.031) and pts. with a maximum TpTe ≤ 78 ms were without any VA leading to AT during follow-up. There was no correlation of maximum TpTe to other clinical parameters in our patient cohort.

CONCLUSION

A prolonged TpTe is associated with VA and AT in HCM. Our findings suggest that TpTe can possibly serve as a marker for ventricular arrhythmogenesis in pts. with HCM and assessment of TpTe might, therefore, optimize SCD risk stratification.

Early segmental relaxation abnormalities in hypertrophic cardiomyopathy for differential diagnostic of patients with left ventricular hypertrophy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is characterized by asymmetric left ventricular hypertrophy (LVH). However, clinical signs can be subtle and differentiation from other causes of LVH is challenging.

HYPOTHESIS

As diastolic dysfunction (DD) is an early sign in HCM, we aimed to find regional changes in relaxation pattern for differentiation from other entities of LVH.

METHODS

In 148 patients (81 HCM, 55 arterial hypertension (AHT), 12 Fabry disease) and 63 healthy controls, relaxation patterns were assessed using regional tissue Doppler imaging. In 42 HCM patients, myocardial mass and fibrosis were quantified by cardiac magnetic resonance imaging and correlated with relaxation parameters.

RESULTS

In HCM the septal to lateral isovolumic relaxation time (s/l IVRT) ratio was higher (1.5 ± 0.4) compared with AHT (1.1 ± 0.2), Fabry disease (1.0 ± 0.1), and controls (1.1 ± 0.2; P < 0.001), showing 77% sensitivity and 79% specificity to discriminate HCM-related LVH from other entities. The s/l IVRT ratio was independent of global DD in HCM (HCM with DD: 1.5 ± 0.5, n = 52; HCM without DD: 1.5 ± 0.3, n = 29) and remained significantly different from other entities in a subgroup of HCM patients with maximum wall thickness < 20 mm (s/l ratio: 1.5 ± 0.5, n = 28). Regional IVRT did not correlate with the corresponding segmental myocardial mass or amount of fibrosis in cardiac magnetic resonance imaging.

CONCLUSIONS

HCM patients show a prolonged septal IVRT irrespective of the extent of LVH and even before developing global DD. The s/l IVRT ratio is significantly higher in HCM compared with AHT or Fabry disease, thus establishing segmental IVRT analysis as a potential parameter for differential diagnosis in LVH.

Evaluation of MYBPC3 trans-Splicing and Gene Replacement as Therapeutic Options in Human iPSC-Derived Cardiomyocytes

Gene therapy is a promising option for severe forms of genetic diseases. We previously provided evidence for the feasibility of trans-splicing, exon skipping, and gene replacement in a mouse model of hypertrophic cardiomyopathy (HCM) carrying a mutation in MYBPC3, encoding cardiac myosin-binding protein C (cMyBP-C). Here we used human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) from an HCM patient carrying a heterozygous c.1358-1359insC MYBPC3 mutation and from a healthy donor. HCM hiPSC-CMs exhibited ∼50% lower MYBPC3 mRNA and cMyBP-C protein levels than control, no truncated cMyBP-C, larger cell size, and altered gene expression, thus reproducing human HCM features. We evaluated RNA trans-splicing and gene replacement after transducing hiPSC-CMs with adeno-associated virus. trans-splicing with 5' or 3' pre-trans-splicing molecules represented ∼1% of total MYBPC3 transcripts in healthy hiPSC-CMs. In contrast, gene replacement with the full-length MYBPC3 cDNA resulted in ∼2.5-fold higher MYBPC3 mRNA levels in HCM and control hiPSC-CMs. This restored the cMyBP-C level to 81% of the control level, suppressed hypertrophy, and partially restored gene expression to control level in HCM cells. This study provides evidence for (1) the feasibility of trans-splicing, although with low efficiency, and (2) efficient gene replacement in hiPSC-CMs with a MYBPC3 mutation.

The mutation p.D313Y is associated with organ manifestation in Fabry disease

Fabry disease (FD) is a multisystem lysosomal storage disorder caused by mutations in the GLA gene. The clinical significance of the mutation p.D313Y is still under debate. Retrospective chart analysis of clinical (neurological, cardiac, renal, and ophthalmological), genetic, and biochemical (lyso-globotriaosylsphingosine, lyso-Gb3; enzyme activity) data was performed in all our patients carrying the p.D313Y mutation. Fourteen patients from 5 families (10 female, 4 male; age range 10-51) were included. Symptoms and organ manifestations compatible with FD could be identified in 10 patients. Cerebrovascular events occurred in 4 females. Seven patients reported pain or acroparaesthesia. Cornea verticillata was found in 1 patient, mild retinal vascular tortuosity in 5 patients. Lyso-Gb3 was elevated in 2 females with cerebrovascular involvement. Classical cardiac, renal or skin manifestations could not be identified. The mutation p.D313Y in the GLA gene may lead to organ manifestations and elevation of the Fabry-specific biomarker lyso-Gb3. Neurological symptoms (stroke and pain) and ocular manifestations seem to be the leading findings. Annual routine visits are recommended for patients carrying the p.D313Y mutation. Enzyme replacement therapy might be considered in symptomatic patients.

Early Detection of Symptomatic Paroxysmal Cardiac Arrhythmias by Trans-Telephonic ECG Monitoring: Impact on Diagnosis and Treatment of Atrial Fibrillation

INTRODUCTION

Diagnosis of infrequent cardiac arrhythmias (CA) is often unsuccessful using resting or Holter ECG. As early detection and treatment of CA, especially atrial fibrillation (AF), has implications on patients' treatment and outcome, we investigated, whether self-guided, trans-telephonic event-recorder monitoring (Tele-ECG) improves diagnosis and influences treatment options.

METHODS

Between 2009 and 2014, 790 patients (54 ± 18 years, 40% male; no history of CA: 582, known AF: 179, other CA: 29) presented with recurrent symptoms suggestive of CA and were screened by Tele-ECG (17.3 ± 26.9 days). A total of 11,775 ECGs were transmitted via a 24-hour telephone hotline including documentation of the respective symptoms.

RESULTS

In 73% of patients, CA was documented at the time of symptoms: sinus tachycardia 23%, premature ventricular beats 19%, AF 14%, supraventricular tachycardia 9%, sinus bradycardia 5%, sinus arrhythmia 2%, and AV block II 1%. The mean time until the first symptomatic episode occurred was 6.9 ± 15.3 days (median 2.5 days). The first documented arrhythmia occurred on average after 7.7 ± 14.1 days (median 3 days). In patients with AF (n = 110), 44% was newly diagnosed. According to the Tele-ECG diagnosis, AF ablation was performed in 27% of these patients, 7% electrical cardioversion, and in 30% antiarrhythmic therapy was initiated. In 65% of the patients with recurrence of known AF, (re-)ablation was performed or recommended and in 16% antiarrhythmic therapy was modified.

CONCLUSIONS

Tele-ECG monitoring is effective in the diagnosis of suspected symptomatic CA. A diagnosis can usually be achieved within 1 week and has implications on patients' care.

Serum Matrix Metalloproteinases as Quantitative Biomarkers for Myocardial Fibrosis and Sudden Cardiac Death Risk Stratification in Patients With Hypertrophic Cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is associated with an increased risk of sudden cardiac death due to ventricular tachycardia (VT), and myocardial fibrosis reflects an important risk factor. Several matrix metalloproteinases (MMPs) and procollagen N-terminal propeptides (PNPs) are involved in collagen turnover and discussed as fibrosis biomarkers. We aimed to identify biomarkers that correlate with myocardial fibrosis in late-gadolinium-enhancement cardiac magnetic resonance imaging (LGE-CMR) and/or cardiac events (syncope, VT) in HCM patients.

METHODS AND RESULTS

In 54 HCM patients (age 55.9 ± 14.3 y, 50% female) fibrosis was quantified by LGE-CMR. Serum concentrations of MMP-1, -2, -3, -9, and tissue inhibitor of MMP (TIMP) 1 were analyzed by means of enzyme-linked immunosorbent assay and PINP, PIIINP, and type I collagen C-terminal telopeptide (ICTP) concentrations by radioimmunoassay. MMP-9 was associated with fibrosis in LGE-CMR (mean increase 0.66 g/unit MMP9 [95% confidence interval [CI] 0.50-0.82]; P < .001) and with cardiac events in women (odds ratio [OR] 1.07 [1.01-1.12], P = .01) but not in men. Increased MMP-2 levels in women were associated with lower fibrosis (0.05 [-0.09 to -0.01]; P = .015). MMP-3 levels were positively associated with cardiac events (OR 1.13 [1.05-1.22]; P = .001) independently from fibrosis and sex. No association was detected for MMP-1, TIMP-1, PNPs, and ICTP.

CONCLUSIONS

These data suggest that MMP-9 is a useful biomarker for fibrosis and cardiac events in female HCM patients, whereas MMP-3 is associated with a higher event rate independent from fibrosis and sex.

The E3 ubiquitin ligase Asb2β is downregulated in a mouse model of hypertrophic cardiomyopathy and targets desmin for proteasomal degradation

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is an autosomal-dominant disease with mutations in genes encoding sarcomeric proteins. Previous findings suggest deregulation of the ubiquitin proteasome system (UPS) in HCM in humans and in a mouse model of HCM (Mybpc3-targeted knock-in (KI) mice). In this study we investigated transcript levels of several muscle-specific E3 ubiquitin ligases in KI mice and aimed at identifying novel protein targets.

METHODS AND RESULTS

Out of 9 muscle-specific E3 ligases, Asb2β was found with the lowest mRNA level in KI compared to wild-type (WT) mice. After adenoviral-mediated Asb2β transduction of WT neonatal mouse cardiomyocytes with either a WT or inactive Asb2β mutant, desmin was identified as a new target of Asb2β by mass spectrometry, co-immunoprecipitation and immunoblotting. Immunofluorescence analysis revealed a co-localization of desmin with Asb2β at the Z-disk of the sarcomere. Knock-down of Asb2β in cardiomyocytes resulted in higher desmin protein levels. Furthermore, desmin levels were higher in ventricular samples of HCM mice and patients than controls.

CONCLUSIONS

This study identifies desmin as a new Asb2β target for proteasomal degradation in cardiomyocytes and suggests that accumulation of desmin could contribute to UPS impairment in HCM mice and patients.

Orthostatic blood pressure test for risk stratification in patients with hypertrophic cardiomyopathy

Background

Hypertrophic cardiomyopathy (HCM) is the most common cause of sudden cardiac death (SCD) in young adults, mainly ascribed to ventricular tachycardia (VT). Assuming that VT is the major cause of (pre-) syncope in HCM patients, its occurrence is essential for SCD risk stratification and primarily preventive ICD-implantation. However, evidence of VT during syncope is often missing. As the differentiation of potential lethal causes for syncope such as VT from more harmless reasons is crucial, HCM patients were screened for orthostatic dysregulation by using a simple orthostatic blood pressure test.

Methods

Over 15 months (IQR [9;20]) 100 HCM patients (55.8±16.2 yrs, 61% male) were evaluated for (pre-)syncope and VT (24h-ECGs, device-memories) within the last five years. Eighty patients underwent an orthostatic blood pressure test. Logistic regression models were used for statistical analysis.

Results

In older patients (>40 yrs) a positive orthostatic test result increased the chance of (pre-) syncope by a factor of 63 (95%-CI [8.8; 447.9], p<0.001; 93% sensitivity, 95%-CI [76; 99]; 74% specificity, 95%-CI [58; 86]). No correlation with VT was shown. A prolonged QTc interval also increased the chance of (pre-) syncope by a factor of 6.6 (95%-CI [2.0; 21.7]; p=0.002).

Conclusions

The orthostatic blood pressure test is highly valuable for evaluation of syncope and presyncope especially in older HCM patients, suggesting that orthostatic syncope might be more relevant than previously assumed. Considering the high complication rates due to ICD therapies, this test may provide useful information for the evaluation of syncope in individual risk stratification and may help to prevent unnecessary device implantations, especially in older HCM patients.

FHL2 expression and variants in hypertrophic cardiomyopathy

Based on evidence that FHL2 (four and a half LIM domains protein 2) negatively regulates cardiac hypertrophy we tested whether FHL2 altered expression or variants could be associated with hypertrophic cardiomyopathy (HCM). HCM is a myocardial disease characterized by left ventricular hypertrophy, diastolic dysfunction and increased interstitial fibrosis and is mainly caused by mutations in genes coding for sarcomeric proteins. FHL2 mRNA level, FHL2 protein level and I-band-binding density were lower in HCM patients than control individuals. Screening of 121 HCM patients without mutations in established disease genes identified 2 novel (T171M, V187L) and 4 known (R177Q, N226N, D268D, P273P) FHL2 variants in unrelated HCM families. We assessed the structural and functional consequences of the nonsynonymous substitutions after adeno-associated viral-mediated gene transfer in cardiac myocytes and in 3D-engineered heart tissue (EHT). Overexpression of FHL2 wild type or nonsynonymous substitutions in cardiac myocytes markedly down-regulated α-skeletal actin and partially blunted hypertrophy induced by phenylephrine or endothelin-1. After gene transfer in EHTs, force and velocity of both contraction and relaxation were higher with T171M and V187L FHL2 variants than wild type under basal conditions. Finally, chronic phenylephrine stimulation depressed EHT function in all groups, but to a lower extent in T171M-transduced EHTs. These data suggest that (1) FHL2 is down-regulated in HCM, (2) both FHL2 wild type and variants partially protected phenylephrine- or endothelin-1-induced hypertrophy in cardiac myocytes, and (3) FHL2 T171M and V187L nonsynonymous variants induced altered EHT contractility. These findings provide evidence that the 2 novel FHL2 variants could increase cardiac function in HCM.

Event-Recorder Monitoring in the Diagnosis of Atrial Fibrillation in Symptomatic Patients: Subanalysis of the SOPAT Trial

In the SOPAT (suppression of paroxysmal atrial tachyarrhythmias) trial, a high number of asymptomatic atrial fibrillation (AF) episodes were registered in patients with symptomatic AF. This subanalysis was performed to answer three questions: (1) Does antiarrhythmic therapy influence the ratio of symptomatic to asymptomatic AF? (2) Are symptoms during AF dependent on the heart rate (HR)? (3) Do symptoms correlate with an episode of AF? Within 60 months 1,033 patients with symptomatic AF were randomized to either quinidine plus verapamil (Q+V) 480/240 mg/day, Q+V 320/160 mg/day, sotalol 320 mg/day, or placebo, and followed up by daily and symptom-triggered ECG event recording. Over 188,634 ECGs were analyzed (87% SR, 7% AF). Symptoms were reported in only 46% of AF-ECGs. Quinidine plus verapamil reduced the ratio of symptomatic to asymptomatic AF, whereas sotalol had no effect (median [%] (25/75% quartile): Q+V 480/240: 33 (0/79), Q+V 320/160: 45 (1/82), sotalol: 56 (7/93), placebo: 63 (8/92)). The HR during AF directly correlates with the occurrence of symptoms (P < 0.001) and was significantly lower during asymptomatic AF in all groups (mean +/- SD: sympt.: 113 +/- 27/minute, asympt.: 103 +/- 27/minute, P < 0.001). Both antiarrhythmics reduced the mean HR compared to placebo (P < 0.001). Analyzing all symptom-triggered ECGs, AF was diagnosed in only 37%, whereas the majority were SR. Taken together, in contrast to sotalol, Q+V reduces the ratio of symptomatic to asymptomatic AF compared with placebo, at least in part by decreasing the heart rate. Furthermore, patients' symptoms are not a reliable surrogate parameter for the prevalence of AF.

[Asymptomatic atrial fibrillation with systematic screening using tele-ECG--relevance for anticoagulation in paroxysmal atrial fibrillation]

Event recorder monitoring plays an important role in the early detection and diagnosis of rhythm disorders such as atrial fibrillation (AF). In a recent study over 1000 patients with symptomatic paroxysmal AF were followed up by daily and symptom triggered ECG self monitoring. Independent of the presence of antiarrhythmic therapy, the incidence of AF was much higher than expected, since over 50% of AF episodes were asymptomatic. Therefore, patients symptoms are not a reliable surrogate parameter for the detection of AF. Moreover, antiarrhythmic therapy does not totally prevent atrial fibrillation, but raises the risk of silent AF episodes by reducing the mean heart rate. Based on these findings, effective anticoagulation should be taken into consideration in patients with paroxysmal AF independent of antiarrhythmic medication. The decision for anticoagulation with cumarine derivates or aspirin is dependent on the age, underlying diseases, and the individual thromboembolic risk in these patients.

[Antiarrhythmic therapy--recent aspects of pharmacologic treatment]

Over the last years the indication for antiarrhythmic therapy has changed due to the development of other therapeutic approaches. However, antiarrhythmics are important in the acute treatment as well as the prevention of recurrent rhythm disorders. In line with the antiarrhythmic agents of class IC and III also beta-blockers, ACE inhibitors and AT (1) antagonists can be used primarily with a lower risk of severe cardiac side effects. Recent studies demonstrate that for patients with atrial fibrillation there was no benefit of rhythm control versus rate control. However, rhythm control with antiarrhythmics is beneficial in the treatment of highly symptomatic or hemodynamically compromised patients. Hybrid therapy and the "pill in the pocket"-strategy seem to be potent new therapeutic options.