Cryoballoon-ablation of atrial fibrillation in patients with heart failure and preserved ejection fraction

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): Deutsches Zentrum für Herz-Kreislauf-Forschung (DZHK)

Background

Co-existence of atrial fibrillation (AF) and heart failure with preserved ejection fraction (HFpEF) is common and severely affects morbidity and prognosis.

Purpose

This study evaluates outcome after cryoballoon-ablation for AF in HFpEF compared to patients without heart failure employing multiple diagnostic modalities.

Methods

A total of 102 patients scheduled for cryoablation of AF with LVEF≥50% were prospectively enrolled. Baseline evaluation included echocardiography, stress echocardiography, six-minute-walk-test, biomarker measurements and quality of life assessment (SF-36). HFpEF was diagnosed according to current guidelines and confirmed applying the HFA-PEFF-Score. Procedural parameters as well as clinical, functional and echocardiographic endpoints at follow-up ≥12 months after AF-ablation were compared between patients with and without HFpEF.

Results

Patients with HFpEF (n=24) were older (median: 73.5 years [Q25: 66.5 years; Q75: 75.8 years] vs. 64.5 years [Q25: 55.0 years; Q75: 71.3 years], P<0.001) and more often female (83.3% vs. 28.2%). They were characterized by more pronounced AF-related symptoms (median EHRA-score: 3.0 [Q25:3.0; Q75:3.0] vs. 2.0 [Q25: 2.0; Q75: 3.0], P<0.001), reduced distance in six-minute-walk-test (median 487.5m [Q25: 378.1m; Q75: 517.8m] vs. 539.0m [Q25: 489.3m; Q75:589.1 m], P<0.001), and higher mean left atrial (LA)-pressure measured at the needle tip at transseptal puncture (14.0mmHg [Q25: 10.3mmHg; Q75: 21.5mmHg] vs. 10.0 mmHg [Q25: 8.0mmHg; Q75: 13.3mmHg], P=0.008). Procedural parameters were comparable between the two subgroups. Rates of AF-recurrence, repeat AF-ablation and AF-related re-hospitalization were increased in HFpEF (Figure 1A-C), which was confirmed after adjusting for intergroup differences in sex and age distribution by multiple regression analysis. There was no improvement of heart failure-related symptoms and persistent elevation of cardiac biomarkers, even in HFpEF-patients with successful restoration of sinus rhythm at follow-up (Figure 2A-C). Echocardiographic follow-up showed progression of adverse LA-remodeling (LA-volume index at baseline: 35.8ml/m2 [Q25: 32.2ml/m2; Q75: 41.9ml/m2] vs. 12-month follow-up: 40.5ml/m2 [Q25: 36.0ml/m2; Q75: 51.4ml/m2], P=0.017) and no improvement in diastolic function in HFpEF (E/e’ at baseline: 9.7 [Q25: 7.8; Q75: 12.1] vs 12-month follow-up: 10.2 [Q25: 8.4; Q75: 11.8], P=0.874), in particular in patients with HFpEF and AF-recurrence. Quality of life improved in patients without HFpEF in both physical and mental summary scales, however, no beneficial effect was seen in HFpEF.

Conclusion

Patients with HFpEF constitute a distinct subgroup with an elevated risk for arrhythmia recurrence after cryoablation of AF. Functional hallmarks and heart-failure related symptoms of HFpEF persisted in our cohort, irrespective of rhythm-status at follow-up. Future research is needed to optimize tailored treatment strategies in HFpEF.

Exploring biomarkers of age in routine diagnostics for the risk stratification of older patients in the emergency department

Objectives

To estimate the association of the routinely applied biological age-related biomarkers hs-TnT, CRP and Hemoglobin (Hb) with mortality for the purpose of older patient's risk stratification in the emergency department (ED).

Design

Exploratory, prospective cohort study with a follow-up at 2.5 years after recruitment start.

Setting and participants

A cardiological emergency department (ED), chest pain unit, of our University Hospital. N=256 cardiological ED patients with a minimum age of 70 years and with an expected life-expectancy above 24h.

Methods

Data from the hospital files were supplemented by a questionnaire. Patients were followed-up for mortality by requesting registry office information.

Results

Among N=256 patients 63 died over the follow-up period. Positive results in each of the three biomarkers alone as well as the combination were associated with increased all-cause mortality at follow-up. The number of positive age-related biomarkers appeared to be strongly indicative of the risk of mortality, even when controlled for major confounders (age, sex, BMI, creatinine clearance, and comorbidity).

Conclusion and implications

In older ED patients, biomarkers explicitly related to biological aging processes such as hs-TnT, CRP and Hb were independently of each other as well as combined associated with an increased risk of all-cause mortality. Thus, they may have the potential to be used to supplement the general risk stratification of older patients in the ED. Validation of the results in a large dataset is needed.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Robert Bosch Foundation, Stuttgart, Germany Kaplan-Meier curves with 95% CIKaplan-Meier curves for patients grouped

Prognostic and reclassification value of serum cathepsin S over the GRACE risk score in patients with non-ST-segment elevation acute coronary syndrome

Background

Cathepsin S is an extracellular matrix degradation enzyme that plays an important role in atherosclerotic cardiovascular disease by inducing vasa vasorum development and atherosclerotic plaque rupture.

Purpose

To determine the prognostic and reclassification value of baseline serum cathepsin S after adjustment for the Global Registry of Acute Coronary Events (GRACE) score, which is a clinical guideline recommended risk score in non-ST-segment elevation acute coronary syndrome (NSTE-ACS).

Methods

Serum cathepsin S was measured by ELISA in 1,129 consecutive patients presenting with acute symptoms to the emergency department for whom a final adjudicated diagnosis of NSTE-ACS was made. All-cause mortality or all-cause death/non-fatal myocardial infarction (MI) after a median follow-up of 21 months were evaluated as the primary or secondary study endpoint, respectively. The Net Reclassification Index (NRI) estimated the reclassification predictive value for risk of each end-point of cathepsin S over the GRACE score.

Results

After a median follow-up of 21 months 101 (8.95%) deaths were reported. The combined endpoint of death or non-fatal MI occurred in 176 (15.6%) patients. Dose-response curve analysis adjusted for the effect of age, gender, diabetes mellitus, high-sensitivity-cardiac troponin T, high-sensitivity C-reactive protein, revascularization and index diagnosis revealed a non-linear association of continuous cathepsin S with all-cause death (P=0.036 for non-linearity; adjusted HR=1.60 for 80th vs. 20th percentiles, P=0.038) or with the combined endpoint (P=0.008 for non-linearity, adjusted HR=1.53 for 80th vs. 20th percentiles, P=0.011). Serum cathepsin S maintained its predictive value for all-cause death (adjusted HR=1.70 highest vs. lowest tertile, 95% CI 1.03–2.82, P=0.039) after adjusting for the GRACE Score. Similarly, cathepsin S predicted the combined endpoint of all-cause death or non-fatal MI (adjusted HR=1.67 highest vs. lowest tertile, 95% CI 1.15–2.42, P=0.007) independently of the GRACE Score. When cathepsin S was added over the GRACE Score it correctly reclassified risk for all-cause death in 20% of the population (P=0.004). Similarly, serum Cathepsin S conferred a significant reclassification value over the GRACE score for all-cause death or non-fatal MI in 15.9% of the population.

Conclusions

Serum cathepsin S is a predictor of mortality and improves risk stratification over the GRACE score in patients with NSTE-ACS. The clinical application of cathepsin S as a novel biomarker in NSTE-ACS should be further explored and validated.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): German Heart Foundation

RBM20-mutations induce disturbed splicing of calcium relevant genes in patient-specific stem cell models of cardiomyopathies

Background and aim

Mutations in the splice factor RBM20 have been identified to account for ∼3% of cardiomyopathies. In particular, the highly conserved RS-domain is a hotspot for disease-associated mutations. Distinct mutations at position 634 in the RS-domain were already described to be associated to dilative cardiomyopathy (DCM) (R634W) or to left ventricular non-compaction cardiomyopathy (LVNC) (R634L), but the molecular mechanisms that govern the heterogenic entity of DCM and LVNC remain largely unknown. We aimed to analyze the molecular driver behind the RBM20 mutation-based DCM and LVNC in a patient-specific stem cell model.

Methods

Human somatic cells from 2 DCM- and 2 LVNC-patients harboring the RBM20-mutations R634W (DCM) or R634L (LVNC) were reprogrammed into induced pluripotent stem cells (iPSC) and differentiated into functional cardiomyocytes (CM). Gene expression, alternative splicing activity, sarcomeric regularity, cAMP level, kinase-specific phosphorylation of important Ca2+ players, and physiological cardiac functions as Ca2+ homeostasis were analyzed (Fluo3 and Fura4). Isogenic rescue lines were generated by CRISPR/Cas9 technology to analyze the direct impact of the RBM20 mutations to the cardiac phenotype.

Results

We investigated the role of RBM20 mutations in DCM and LVNC-iPSC-CMs RBM20-splicing and observed common splice defects in titin-isoform-switch or a 24bp insertion in the gene ryanodine receptor 2 (RYR2).. In contrast, the calcium-handling gene Camk2δ was predominantly mis-spliced in LVNC-CMs, whereas the structural gene LDB3 was mis-spliced in DCM-CMs. As a possible consequence of splice defects in sarcomeric genes both DCM and LVNC-CMs exhibited an irregular sarcomeric structure at the Z-disk and M-line. Interestingly, the LVNC-CMs showed faster Ca2+ transient decay time and weakened response to β-adrenergic stimulation. In contrast, the DCM-CMs did exhibit increased Ca2+-sparks and decreased systolic and diastolic Ca2+ highlighting that two distinct missense mutations can lead to different pathological Ca2+ phenotypes. Ca2+ kinetic defects in LVNC-iPSC-CMs were independent of cAMP, but in line with Camk2δ-dependent hyperphosphorylation of the specific target PLN. Isogenic WT-iPSC lines were generated using CRISPR/Cas9 technology and underscored the role of RBM20-mutations in cardiomyopathies as the sarcomeric defects, Ca2+ cycling and leakage were rescued for both LVNC-CMs and DCM-CMs.

Conclusion

We show the first iPSC-model of splice-defect-associated RBM20-dependent LVNC and DCM. Our data demonstrate that RBM20-R634L induce mis-splicing of Camk2δ leading to hyperphosphorylation of PLN-Thr17 along with increased Ca2+ kinetics in LVNC, whereas RBM20-R634W induced RYR2-dependent Ca2+ leak with disturbed systolic and diastolic Ca2+in DCM. Taken together these results suggest that the molecular aberrations in alternative splicing differ depending on the distinct missense mutation in RBM20.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): BMBF, DZHK German Center for Cardiovascular research

P5259Evaluation of functional impairment and cardiac remodelling in isolated left branch bundle block using magnetic resonance imaging

Introduction

Left bundle-branch block (LBBB) is associated with underlying cardiovascular abnormalities, such as dilated cardiomyopathy and coronary heart disease. However, an isolated LBBB can be found in individuals without detectable cardiovascular disease. Echocardiographic studies demonstrated a reduced left ventricular (LV) ejection fraction (EF) and an increased LV cavity volume and mass in patients with isolated LBBB. Recent studies have shown larger cavity volumes (end-diastolic volume – EDV; end-systolic volume – ESV) and lower LVEF using CMR. However, there is still limited data on cardiac function, volumes and mass and the correlation between the parameters and the QRS duration (QRS) in patients with isolated LBBB.

Purpose

In this retrospective study LV function, volume, mass, T1-values and myocardial strain were measured and correlation between QRS duration in patients with isolated LBBB was identified using CMR.

Methods

Potential cases were identified from our local database, who underwent CMR during 2015–2018. We excluded patients with echocardiographic abnormalities besides abnormal septal motion or greater than a mild valve disease, known cardiovascular disease (coronary artery disease, cardiomyopathy or arrhythmia), history of potential cardiotoxic chemotherapy. We could identify 26 adults, who underwent CMR in a 1.5- or 3-Tesla scanner. LBBB was confirmed by ECG prior to CMR by a cardiologist. T1-values (MOLLI) were available in 19 patients. Myocardial strain (tissue tracking) could be performed in 23 patients. Associations were tested using Pearson's correlation analysis.

Results

26 patients (age 61.5±9.6 years, 19 women, BMI 25.4 (18.2–38.1)) with isolated LBBB were included (QRS duration: 138±12ms). CMR results in the cohort revealed a reduced LVEF (53.4±3,8%) and slightly enlarged LV cavity when corrected to body-surface area (BSA) (LV-EDV/BSA: 83.7±13.8ml/m2; LV-ESV/BSA: 39.3±8.6ml/m2), when compared to normal values from the study center. There is a negative correlation between LVEF and QRS duration (r=−0.550, p<0.05) and a positive correlation between QRS duration and LV-EDV/BSA (r=0.627, p<0.05) as well as between QRS and LV-ESV/BSA (r=0.661, p<0.05). In addition, there is a positive correlation between QRS duration and myocardial mass (r=0.645, p<0.05), septal myocardial thickness (r=0.405, p<0.05) and lateral wall thickness (r=0.495, p<0.05). In addition, there is a positive correlation between LV longitudinal strain and QRS (r=0.449, p<0.05). T1-values were in normal range. There is no correlation between QRS and T1-values.

Conclusion

Using CMR a negative correlation between LV function and QRS duration and the positive correlation between LV volumes and QRS duration in patients with isolated LBBB could be identified. The absence of significant myocardial fibrosis with normal T1-values indicates an electromechanical dissociation rather than an underlying myocardial abnormality as an explanation for the reduced LVEF.

P1757GLP-1 levels predict cardiovascular risk in patients with acute myocardial infarction

Background

Glucagon-like peptide 1 (GLP-1) is a gut incretin hormone, which induces post-prandial glucose-dependent insulin secretion. GLP-1 receptor agonists improve cardiovascular outcomes in patients with diabetes at high cardiovascular risk. We recently found GLP-1 levels to be increased in patients with acute myocardial infarction.

Purpose

The aim of this study was to assess the predictive capacity of GLP-1 for cardiovascular outcome in patients with myocardial infarction.

Methods

Total GLP-1 levels, NT-proBNP concentrations and the Global Registry of Acute Coronary Events (GRACE) score were assessed at time of admission in 918 patients with myocardial infarction presenting with acute chest pain. Among these 597 patients presented with NSTEMI and 321 with STEMI. The primary composite outcome of the study was the first occurrence of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke with a median follow-up of 311 days.

Results

Kaplan-Meier survival plots (separated by tertiles with cut-off values 35.44 and 53.45) and univariate cox regression analyses found GLP-1 values to be associated with adverse outcome (combined endpoint and all-cause mortality) (logarithmized GLP-1 values HR: 5.459; p<0.0001). Further adjustment for age, sex, previous cardiovascular disease, diabetes, hypertension, hypercholesterinemia, kreatinin, CRP, troponin T and NT-proBNP levels did not affect the association of GLP-1 with adverse outcomes (p=0.0341). Receiver operating characteristic curve analyses illustrated that GLP-1 is a strong indicator for early events (area under the curve of the combined endpoint at 7 days: 0.79; 14 days: 0.81; 30 days: 0.80 and 183 days: 0.64), which proved to be superior to Troponin T, serum creatinin, NT-proBNP and CRP within the first 100 days. Adjustment of the GRACE risk estimate by GLP-1 increased the area under the receiver-operating characteristic curve (AUC) after 1 month from 0.86 to 0.89 in NSTEMI patients. Addition of GLP-1 to a model containing GRACE and NT-proBNP led to a further improvement in model performance (increase in AUC from 0.88 for GRACE + NT-proBNP to 0.90 for GRACE + NT-proBNP + GLP-1).

Conclusion

GLP-1 is a new biomarker of cardiovascular risk and adverse outcomes in patients with acute myocardial infarction and improves the predictive value of the GRACE score in patients with NSTEMI.

1206Doxapram is a promising new antiarrhythmic drug for an atrial-specific therapy of atrial fibrillation

Background

TASK-1 (K2P3.1) is an atrial-specific two-pore domain potassium channel that is significantly upregulated in atrial fibrillation (AF) patients resulting in shortened atrial action potential duration (APD). Inhibition of TASK-1 in human atrial cardiomyocytes reverses AF-related APD shortening to values observed in patients with sinus rhythm (SR). By in silico-modelling and experimental characterization of drug binding sites, doxapram was identified as specific inhibitor of TASK-1.

Purpose

In this study, we investigated the antiarrhythmic efficacy of doxapram in a porcine model of AF to convert and suppress AF.

Methods

We established a new porcine model of persistent AF without induced tachymyopathy. AF was induced in domestic pigs by intermittent atrial burst stimulation using implanted pacemakers. During AF episodes, burst stimulation was inhibited by an integrated pacemaker biofeedback algorithm. AV-node ablation was performed to prevent AF-associated heart failure. All pigs underwent catheter-based electrophysiological investigations prior to and after 14 days doxapram treatment. Pigs in the treatment group received intravenous applications of doxapram twice per day. Rhythm status was continuously recorded by intracardiac long-term ECG monitors. The application of doxapram for cardioversion and long term suppression of AF in pigs with persistent AF was evaluated. Subsequent to the doxapram treatment, porcine cardiomyocytes were isolated from right and left atria and electrophysiologically investigated by patch-clamp and multi-electrode experiments. Atrial electrical remodeling was characterized by analyses of ion channel expression at mRNA and protein levels.

Results

TASK-1 mRNA, protein and transmembrane current were significantly increased in AF pigs compared to SR controls, resulting in shortened atrial APDs. In doxapram-treated AF pigs the AF burden was significantly reduced. After 14 days treatment with doxapram, TASK-1 currents and atrial APDs recorded in porcine cardiomyocytes were reduced and similar to values of SR animals. Doxapram could be successfully applied for cardioversion in pigs with persistent AF. On average, cardioversion was observed 3 minutes after doxapram application.

Conclusion

Doxapram significantly suppressed AF episodes and normalized cellular electrophysiological characteristics in a porcine model of AF through inhibition of the TASK-1 ion channel. Furthermore, doxapram rapidly converted AF into SR in pigs. Therefore, doxapram might serve as a new antiarrhythmic drug to treat AF in patients.

2228Circulating serum extracellular matrix degradation enzyme cathepsin S predicts mortality and improves risk stratification over the GRACE score in patients with non-ST elevation acute coronary syndrom

Background

Blood-based biomarkers may be useful in the identification of residual risk for death or acute myocardial infarction (AMI) in patients with a previous acute coronary syndrome. Cathepsin S (CTSS) is a lysosomal cysteine protease with potent elastolytic and collagenolytic activity, which plays an important role in cardiovascular disease through extracellular matrix degradation, vasa vasorum development and atherosclerotic plaque rupture. The aim of the present study was to determine the prognostic and reclassification value of baseline circulating levels of CTSS after adjustment for the Global Registry of Acute Coronary Events (GRACE) score, which is widely recommended for risk stratification in non-ST-segment elevation acute coronary syndrome (NSTE-ACS).

Methods

CTSS was measured in blood samples collected from 1,129 consecutive patients with adjudicated NSTE-ACS presenting at an acute chest pain unit for evaluation of a possible acute coronary syndrome. Cardiovascular (CV) death and a composite of all-cause mortality and AMI were evaluated as the primary and secondary endpoints of the study, respectively. The additive prognostic value of CTSS over the GRACE score was estimated by the Net Reclassification Index (NRI) that examines the net upward and downward reclassification into correct pre-defined risk categories.

Results

After a median follow-up of 21 months, 101 (8.95%) deaths were reported, of which 63 (5.6%) were of cardiac origin. The combined endpoint occurred in 176 (15.6%) patients. Patients with CTSS in the highest tertile presented the greatest risk for all-cause mortality (HR=1.84 for highest versus lowest tertile of CTSS distribution, 95% CI 1.1–3.08, P=0.02) and CV death (HR=2.5 for highest versus lowest tertile of CTSS distribution, 95% CI 1.24–5.05, P=0.011) after adjustment for age, gender, diabetes mellitus, hs-cTnT, hsCRP, revascularization and index diagnosis. Similarly, CTSS was associated with increased risk of cardiovascular death after adjusting for the GRACE Score (adjusted HR for highest versus lowest tertile of CTSS distribution=2.34, 95% CI 1.18–4.64, P=0.015). Further, CTSS predicted the combined endpoint of all-cause death or non-fatal MI independently of the GRACE Score (adjusted HR for highest versus lowest tertile of CTSS distribution=1.67, 95% CI 1.15–2.42, P=0.007). When CTSS was added over the GRACE Score, it conferred significant reclassification value for CV death (NRI=21.4%, P=0.008). Similarly, CTSS correctly reclassified risk for all-cause death or non-fatal MI (P=0.006) in 15.9% of the population.

Conclusions

Circulating CTSS predicts mortality and improves risk stratification of patients with NSTE-ACS over the GRACE score recommended by clinical guidelines. The clinical application of CTSS as a novel biomarker in NSTE-ACS should be further explored and validated.

1439PRAS40 attenuates mTOR-dependent endothelial inflammation and atherosclerosis

Introduction

Endothelial inflammation plays a pivotal role in atherosclerosis. Many inflammatory and metabolic signals converge upon mechanistic target of rapamycin (mTOR), and inhibition of mTOR has been shown to reduce atherosclerosis. However, clinical use of mTOR-inhibitors is limited by serious adverse effects, of which insulin resistance and dyslipidemia are particularly troubling in the context of atherosclerosis. In that respect, targeting PRAS40, an endogenous modulator of mTOR complex 1 (mTORC1) with highly cell type-specific effects on mTOR signaling, may be a more promising approach. In fact, we have previously demonstrated that, in contrast to conventional mTOR inhibitors, PRAS40 gene therapy substantially improves metabolic profile in obese mice. However, the function of PRAS40 in endothelial cells and its role in atherosclerosis have never been investigated.

Methods and results

To define the impact of PRAS40 on endothelial mTORC1-signaling in this context, cultured human umbilical vein endothelial cells (HUVECs) were exposed to the atherogenic cytokine TNFα. TNFα induced mTOR signaling as evidenced by increased phosphorylation of S6 kinase and ribosomal S6 protein. Interestingly, this effect was strongly augmented upon siRNA-mediated knock-down of PRAS40, indicating a negative regulation of mTORC1 by PRAS40 in endothelial cells. Moreover, PRAS40-knockdown promoted TNFα-induced inflammatory signaling as reflected by increased proliferative activity, upregulation of atherogenic markers like CCL2 and VCAM-1, as well as enhanced monocyte recruitment in the THP-1 adhesion assay. In contrast, PRAS40-overexpression blocked TNFα-induced activation of mTORC1 and consistently suppressed all of these measures of inflammatory activation. All effects of PRAS40-overexpression could be reproduced by the mTORC1 inhibitors rapamycin and torin1. Thus, our in vitro studies suggest that in endothelial cells PRAS40 exerts anti-atherogenic effects by negative regulation of mTORC1. To validate these findings in vivo in the context of atherosclerosis we created transgenic mice with tamoxifen-inducible endothelium-specific PRAS40-deficiency (EC-PRAS40-KO). These mice were exposed to a model of accelerated atherosclerosis based on western diet and partial carotid ligation: Four weeks after partial carotid ligation, neointimal and atherosclerotic lesion formation was strongly enhanced in EC-PRAS40-KO mice. Moreover, mTORC1 activity as well as CCL2 and VCAM-1 expression were markedly increased compared to control mice.

Conclusion

Our data indicate that PRAS40 suppresses atherosclerosis via inhibition of mTORC1-mediated inflammatory signaling in endothelial cells. In conjunction with its favourable effects on metabolic homeostasis, the overall therapeutic profile of PRAS40-treatment appears to be beneficial compared to conventional mTOR-inhibitors. Taken together PRAS40 may qualify as a promising therapeutic target for the treatment of atherosclerosis.

Acknowledgement/Funding

German Federal Ministry of Education and Research, DZHK (German Centre for Cardiovascular Research)

P5267Cardiac tissue characterization in patients with wilsons disease using magnetic resonance imaging

Introduction

Wilson's disease (WD) is a rare autosomal recessive copper disorder with limited excretion of excess copper into the bile. Primary symptoms are hepatic or neurological. However, the clinical range of WD is wide and can result in cardiac symptoms as well. Previous studies revealed a higher incidence of heart failure in WD patients compared to the rest of the population.

Purpose

Cardiac magnetic resonance imaging (CMR) is used to identify the typical features of several systemic disorders with excessive myocardial deposition of substrates. The aim of this study was to perform a cardiac tissue characterization in WD patients by using CMR and to identify subgroups of WD patients with reduced ejection fraction (EF).

Methods

Patients with known WD using Ferenci-Score were included in this prospective study. WD patients were referred to 1.5 Tesla CMR. The following CMR protocol was performed; Cine-images, T1-, T2- and T2*-Mapping, fast-SENC strain and late gadolinium enhancement (LGE). Fast-SENC strain measurements were compared with values from healthy individuals scanned at the center.

Results

43 patients (age 38.7±12.8 years, 20 female, BMI 23.80 (17.4–33.1)) with WD could be identified and were evaluated with CMR. CMR revealed normal left ventricular (LV) EF (62.4±5.4%) and right ventricular (RV) EF (64.4±7.1%) overall. However, three patients (7%), who suffered primarily from neurological symptoms, were found to have mildly reduced LV-EF (46.5%, 51%, and 53.5%). Strain analysis revealed significantly reduced LV global circumferential strain (GCS) overall compared to healthy individuals (WD (%): −19.2 2.7; control (%): −20.71±1.5, p<0.05). Patients with primarily hepatic symptoms (WD-h) did not show reduced strain measurements compared to the control group. Patients suffering from primarily neurological symptoms (WD-n) showed significantly reduced LV GCS compared to healthy individuals (WD-n (%): −18.3±3.1; control (%): −20.7±1.5, p<0.05) and RV GCS (WD-n (%): −17.5±3.0; control (%): −19.2±1.8, p<0.05). Also, LV GCS in WD-n was significantly reduced compared to WD-h (WD-n (%): −18.3±3.1; WD-h (%): −20.0±2.0). Furthermore, there were no significant differences between the two subgroups, besides a significant thicker lateral wall in patients with WD-n (WD-n (mm): 7 (5–9); WD-h (mm): 6 (5–8), p<0.05). T1-, T2- and T2*-Mapping did not show any pathological pattern and were overall in the normal range (T1: 1020±30ms; T2: 52.9±3.0ms; T2*: 38.4±5.6ms). Epicardial LGE was present in 1 patient.

Conclusion

Cardiac tissue characterization was performed in WD patients using CMR. Reduced EF, LV and RV GCS have been detected in patients with primarily neurological symptoms. Cardiovascular autonomic dysfunction in this subgroup could be a reason for the reduced biventricular strain. It is unknown if reduced circumferential strain influences the prognosis of WD patients, which should be investigated in further studies.

Multicenter analytical evaluation of a high-sensitivity troponin T assay

BACKGROUND

High-sensitivity cardiac troponin assays are being introduced clinically for earlier diagnosis of acute myocardial infarction (AMI). We evaluated the analytical performance of a high-sensitivity cardiac troponin T assay (hscTnT, Roche Diagnostics) in a multicenter, international trial.

METHODS

Three US and 5 European sites evaluated hscTnT on the Modular® Analytics E170, cobas® 6000, Elecsys 2010, and cobas® e 411. Precision, accuracy, reportable range, an inter-laboratory comparison trial, and the 99th percentile of a reference population were assessed.

RESULTS

Total imprecision (CVs) were 4.6-36.8% between 3.4 and 10.3 ng/L hscTnT. Assay linearity was up to 10,000 ng/L and the limit of blank and detection were 3 and 5 ng/L, respectively. The 99th percentile reference limit was 14.2 ng/L (n=533). No significant differences between specimen types, assay incubation time, or reagent lots existed. A substantial positive bias (76%) exists between the 4th generation and hscTnT assays at the low end of the measuring range (<50 ng/L). hscTnT serum pool concentrations were within 2SD limits of the mean of means in the comparison trial, indicating comparable results across multiple platforms and laboratories.

CONCLUSION

The Roche hscTnT assay conforms to guideline precision requirements and will likely identify additional patients with myocardial injury suspicious for AMI.

Troponin elevation in coronary vs. non-coronary disease

Acute myocardial infarction is defined as myocardial cell death due to prolonged myocardial ischaemia. Cardiac troponins (cTn) are the most sensitive and specific biochemical markers of myocardial injury and with the new high-sensitivity troponin methods very minor damages on the heart muscle can be detected. However, elevated cTn levels indicate cardiac injury, but do not define the cause of the injury. Thus, cTn elevations are common in many disease states and do not necessarily indicate the presence of a thrombotic acute coronary syndrome (ACS). In the clinical work it may be difficult to interpret dynamic changes of troponin in conditions such as stroke, pulmonary embolism, sepsis, acute perimyocarditis, Tako-tsubo, acute heart failure, and tachycardia. There are no guidelines to treat patients with elevated cTn levels and no coronary disease. The current strategy of treatment of patients with elevated troponin and non-acute coronary syndrome involves treating the underlying causes. The aim of this paper is to review data from studies of non-ACS patients with acutely elevated troponin who in clinical practice may be difficult to discriminate from ACS patients.