Serum cardiac troponin I is related to increased left ventricular wall thickness, left ventricular dysfunction, and male gender in hypertrophic cardiomyopathy

Role of Biomarkers of Myocardial Injury to Predict Adverse Outcomes in Hypertrophic Cardiomyopathy

BACKGROUND

Serum troponins and CK-MB (creatine kinase-MB) are readily detectable and reliable cardiac-specific biomarkers of subclinical myocardial injury. This study explores the roles of cTnI (cardiac troponin I) and CK-MB in hypertrophic cardiomyopathy (HCM).

METHODS

This study included 1045 patients with HCM who had baseline cTnI and CK-MB measurements at Fuwai Hospital between 1999 and 2019. Patients were excluded if they had undergone percutaneous coronary intervention or coronary artery bypass grafting, or had renal failure. Five end points were studied: all-cause death, cardiovascular death, noncardiovascular death, sudden cardiac death, and other cardiovascular death. Cox regression was used to assess the associations of cTnI and CK-MB levels with outcomes.

RESULTS

Nine hundred seventy patients with available follow-up data were finally analyzed (mean age, 49.3 years; 36.4% female). During the median 4.3-year follow-up period, 87 patients reached the end points. Higher cTnI (per 0.05 ng/mL increase) and CK-MB (per 1 IU/L increase) levels were associated with increased risks of all-cause death (cTnI: adjusted hazard ratio [HR], 1.038, P<0.001; CK-MB: adjusted HR, 1.021, P=0.004), cardiovascular death (cTnI: adjusted HR, 1.040, P<0.001; CK-MB: adjusted HR, 1.025, P=0.006), and sudden cardiac death (cTnI: adjusted HR, 1.045, P<0.001; CK-MB: adjusted HR, 1.032, P=0.001). Patients with elevated levels of both cTnI and CK-MB had worse prognoses than patients with an elevated level of either biomarker alone and patients who did not have an elevated level of either biomarker. Addition of the binary indicator elevation of both cTnI and CK-MB significantly improved the discrimination and reclassification abilities of the standard HCM Risk- sudden cardiac death model (C statistics: P=0.002; net reclassification improvement, 0.652; integrated discrimination improvement, 0.064).

CONCLUSIONS

Comprehensive evaluations of biomarkers of myocardial injury, cTnI and CK-MB, have considerable value for predicting adverse outcomes among patients with HCM. Routine cTnI and CK-MB assessments may help to guide implantable cardioverter defibrillator implantation for primary prevention in HCM.

Circulating Biomarkers in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy is the most common genetic heart disease. Biomarkers, molecules measurable in the blood, could inform the clinician by aiding in diagnosis, directing treatment, and predicting outcomes. We present an updated review of circulating biomarkers in hypertrophic cardiomyopathy representing key pathologic processes including wall stretch, myocardial necrosis, fibrosis, inflammation, hypertrophy, and endothelial dysfunction, in addition to their clinical significance.

Association of NT-proBNP and hs-cTnT with Imaging Markers of Diastolic Dysfunction and Focal Myocardial Fibrosis in Hypertrophic Cardiomyopathy

Serum biomarkers such as N-terminal prohormone of the brain natriuretic peptide (NT-proBNP) and cardiac troponins are elevated in patients with hypertrophic cardiomyopathy (HCM). At present, it is not clear if these markers are associated with distinct clinical alterations in HCM, such as left ventricular hypertrophy, outflow tract obstruction, myocardial fibrosis and/or diastolic dysfunction (DD), which are associated with adverse cardiovascular outcome. Here we evaluate the association of NT-proBNP and high sensitivity cardiac troponin T (hs-cTnT) to a variety of cardiac imaging parameters in HCM patients in a multivariable regression analysis. This retrospective cross-sectional study included 366 HCM patients who underwent transthoracic echocardiography (TTE), 218 of whom also obtained cardiovascular magnetic resonance (CMR) to assess focal myocardial fibrosis by LGE. Multivariable regression analyses revealed the strongest association of the DD parameters E/E′ mean and E/E′ septal with NT-proBNP (b = 0.06, 95%-CI [0.05−0.07], p < 0.001, R2 = 0.28; b = 0.08, 95%-CI [0.06−0.1], p < 0.001, R2 = 0.25) and LGE size showed the strongest association with hs-cTnT (b = 0.20, 95%-CI [0.15−0.24], p < 0.001, R2 = 0.28). This study indicates that NT-proBNP and hs-cTnT are associated with structural and functional alterations in HCM. NT-proBNP is a stronger predictor for DD, while hs-cTnT is associated with the extent of focal myocardial fibrosis. Both biomarkers might be useful in the diagnostic procedure in addition to imaging parameters.

Alteration of serum biomarkers in patients with hypertrophic cardiomyopathy with and without atrial fibrillation

Aim: We sought to determine the relationship between presence of atrial fibrillation (AF) and serum biomarkers, including native thiol (antioxidant), disulphide/native thiol ratio, Hs-CRP and high-sensitivity Troponin-I (Hs-TnI) in hypertrophic cardiomyopathy (HCM). Materials & methods: We enrolled consecutive 121 HCM outpatients without AF and 40 HCM outpatients with AF. A 12-lead electrocardiogram, transthoracic echocardiography and 24/48-h ambulatory rhythm monitoring were performed for all patients. Fasting venous blood samples were taken from all study patients to measure serum thiol-disulphide homeostasis, Hs-CRP and Hs-TnI. Results: Serum-native thiol was lower and disulphide/native thiol ratio was more oxidized in HCM patients with AF (p < 0.001). Also, HCM patients with AF had higher Hs-TnI and Hs-CRP than no-AF HCM patients. Disulphide/native thiol ratio, serum-native thiol, age, NYHA functional class≥III, and advanced diastolic dysfunction were independently associated with the presence of AF in HCM. Conclusion: In addition to clinical and echocardiographic findings, oxidative stress is also associated with AF in HCM patients.

Is there any relationship between biomarkers and echocardiographic markers in patients with pulmonary stenosis underwent balloon valvuloplasty?

BACKGROUND

Congenital pulmonary stenosis (PS) is a progressive disease. Balloon pulmonary valvuloplasty (BPV) is the treatment of choice in valvular PS.

AIM

We aim to study the relationship between biomarkers and echocardiographic markers in valvular PS and to assess the impact of BPV on these markers.

PATIENTS AND METHODS

Patients with moderate and severe valvular PS amenable for BPV were recruited. Serum troponin I was measured. Echocardiographic assessment of PS and right ventricular (RV) function was done. All patients underwent BPV. Troponin level and echocardiographic data were re-assessed 2 weeks and 6 months after BPV.

RESULTS

Fifty patients with valvular PS were recruited. There was significant correlation between peak SPG and troponin (P < .001). Troponin was significantly decreased 2 weeks after BPV. Similarly, there was an initial improvement in RV function. After 6 months of follow-up, we divided patients into two groups: Group A: 36 patients with no restenosis. Group B: 14 patients with restenosis. There were high significant differences between both groups regarding troponin level and RV functions with re-elevated troponin in Group B that correlated with peak PG (r = .9, P < .001). RV function parameters in Group B became significantly worse 6 months after BPV than those after the initial 2 weeks.

CONCLUSION

Troponin correlates with the severity of PS and associates with RV dysfunction. Both troponin and RV functions improved with BPV. Recurrent elevation of troponin and impairment of RV function is associated with PV restenosis and could be set as an indication for repeated balloon dilatation of PV.

Correlations between cardiac troponin I and nonsustained ventricular tachycardia in hypertrophic obstructive cardiomyopathy

BACKGROUND

Nonsustained ventricular tachycardia (NSVT) is an independent risk factor for sudden cardiac death (SCD) in patients with hypertrophic obstructive cardiomyopathy (HOCM). However, data concerning the correlations of cardiac biomarkers and NSVT in HOCM are rather limited.

HYPOTHESIS

Our study aimed to investigate the associations between the occurrence of NSVT and circulating biomarkers representing myocardial injury (cardiac troponin I, cTnI), cardiac function (N-terminal pro-brain natriuretic peptide, NT-pro BNP), and inflammation (high-sensitivity C-reactive protein) in a large Chinese HOCM cohort.

METHODS

A total of 755 consecutive HOCM patients were recruited. Systematic cardiac evaluations and circulating biomarkers were examined routinely in all subjects under the clinically stable status. According to the results of 24-hour Holter monitoring, patients were divided into the NSVT group (n = 138) and the nonventricular tachycardia (non-VT) group (n = 617).

RESULTS

Compared with the non-VT group, circulating levels of both cTnI and NT-pro BNP elevated significantly in patients with positive NSVT episodes (P < .001). Multivariable analyses demonstrated that cTnI was independently associated with the presence of NSVT (OR = 1.675, 95% CI: 1.406-1.994, P < .001). Concentrations of cTnI increased progressively not only with the aggravation of ventricular arrhythmic events (P < .001), but also with the growing risk of SCD in HOCM patients (P < .001). Serum cTnI ≥ 0.0265 ng/mL indicated predictive value for the occurrence of NSVT in the HOCM cohort (area under the curve = 0.707, 95% CI: 0.660-0.754, P < .001).

CONCLUSIONS

Elevated cTnI was an independent determinant of NSVT, and it seemed to be valuable for assessing the clinical status of ventricular arrhythmias and the risk of SCD in patients with HOCM.

Diffusion-weighted imaging in hypertrophic cardiomyopathy: association with high T2-weighted signal intensity in addition to late gadolinium enhancement

Diffusion-weighted imaging (DWI) has been confirmed to be associated with late gadolinium enhancement (LGE) in hypertrophic cardiomyopathy (HCM). In this context, we aimed to study whether DWI could reflect the active tissue injury and edema information of HCM which were usually indicated by T2 weighted images. Forty HCM patients were examined using a 3.0 T magnetic resonance scanner. Cine, T2-weighted short tau inversion recovery (T2-STIR), DWI and LGE sequences were acquired. T1 mapping was also included to quantify the focal and diffuse fibrosis. Cardiac troponin I (cTnI) was tested to assess the recently myocardial injury. Student's t-test, Mann-Whitney U test, One-way analysis, Kruskal-Wallis analysis, the Spearman correlation analysis, and multivariable regression were used in this study. The apparent diffusion coefficient (ADC) was significantly elevated in the cTnI positive group (P = 0.01) and correlated with LGE (ρ = 0.312, P = 0.049) and HighT2 extent (ρ = 0.443, P = 0.004) in the global level. In the segmental analysis, the ADC significantly differentiated the segments with and without HighT2/LGE presence (P = 0.00). The average ADC values were higher in segments with HighT2 and LGE coexistence than in those with only LGE presence (P < 0.05). Multivariable regression indicated that segmental HighT2 and LGE were both contributing factors to the ADC values. In this study of HCM, we confirmed that ADC as a molecular diffusion parameter reflects the replacement fibrosis of myocardium. Moreover, it also reveals edema extent and its association with serum cTnI.

Assessment of left ventricular systolic function in hypertrophic cardiomyopathy patients with myocardial injury: a study based on layer-specific speckle tracking echocardiaography

We conducted this study to investigate left ventricle (LV) systolic function in endocardial, mid-myocardial, and epicardial layers by two-dimensional (2D) speckle tracking echocardiography (STE) in hypertrophic cardiomyopathy (HCM) patients with myocardial injury indexed by elevated serum cardiac troponin I (cTnI). Twenty-nine HCM patients with myocardial injury, thirty-five HCM patients without myocardial injury, and ninty-one healthy controls were enrolled in this study. Serum cTnI > 0.026 ng/mL was defined as myocardial injury. LV longitudinal and circumferential strain (LS and CS) were assessed in endocardial, mid-myocardial and epicardial layers. Layer-specific LS and CS differed significantly (all P < 0.001) among all three groups in all three layers, in a descending order from healthy controls to HCM patients without myocardial injury to HCM patients with myocardial injury. Layer-specific LS and CS were decreased the most in HCM patients with myocardial injury indexed by elevated seum cTnI (all P < 0.05). In HCM patients with myocardial injury, layer-specific LS and CS were significantly lower in the segments with greater hypertrophy (segmental thickness ≥ 15 mm) (all P < 0.001) except for endocardial CS (P > 0.05). Layer-specific evaluation of LV strain may improve understanding of impaired LV systolic function in HCM patients with myocardial injury, thus preventing further damage.

Sexual dimorphism in cardiac transcriptome associated with a troponin C murine model of hypertrophic cardiomyopathy

Heart disease remains the number one killer of women in the US. Nonetheless, studies in women and female animal models continue to be underrepresented in cardiac research. Hypertrophic cardiomyopathy (HCM), the most commonly inherited cardiac disorder, has been tied to sarcomeric protein variants in both sexes. Among the susceptible genes, TNNC1-encoding cardiac troponin C (cTnC)-causes a substantial HCM phenotype in mice. Mice bearing an HCM-associated cTnC-A8V point mutation exhibited a significant decrease in stroke volume and left ventricular diameter and volume. Importantly, isovolumetric contraction time was significantly higher for female HCM mice. We utilized a transcriptomic approach to investigate the basis underlying the sexual dimorphism observed in the cardiac physiology of adult male and female HCM mice. RNA sequencing revealed several altered canonical pathways within the HCM mice versus WT groups including an increase in eukaryotic initiation factor 2 signaling, integrin-linked kinase signaling, actin nucleation by actin-related protein-Wiskott-Aldrich syndrome family protein complex, regulation of actin-based motility by Rho kinase, vitamin D receptor/retinoid X receptor activation, and glutathione redox reaction pathways. In contrast, valine degradation, tricarboxylic acid cycle II, methionine degradation, and inositol phosphate compound pathways were notably down-regulated in HCM mice. These down-regulated pathways may be reduced in response to altered energetics in the hypertrophied hearts and may represent conservation of energy as the heart is compensating to meet increased contractile demands. HCM male versus female mice followed similar trends of the canonical pathways altered between HCM and WT. In addition, seven of the differentially expressed genes in both WT and HCM male versus female comparisons swapped directions in fold-change between the sexes. These findings suggest a sexually-dimorphic HCM phenotype due to a sarcomeric mutation and pinpoint several key targetable pathways and genes that may provide the means to alleviate the more severe decline in female cardiac function.

Cardiac Troponin I and T Are Associated with Left Ventricular Function and Structure: Data from the Akershus Cardiac Examination 1950 Study

Background

Concentrations of cardiac troponin I (cTnI) and T (cTnT) are associated with clinical cardiac outcomes, but do not correlate closely in subjects recruited from the general population. Accordingly, we hypothesized that cTnI and cTnT concentrations would be influenced by different cardiovascular (CV) and non-CV risk factors and reflect different CV phenotypes.

Methods

We measured cTnI and cTnT with last generation assays in 1236 women and 1157 men with no known CV disease participating in the prospective observational Akershus Cardiac Examination 1950 Study. All study participants underwent extensive CV phenotyping at baseline, including detailed echocardiography.

Results

Concentrations of cTnI were measurable in 60.3% and cTnT in 72.5% of study participants (P &lt; 0.001), and correlated moderately (r = 0.53; P &lt; 0.001). cTnI was more strongly associated with male sex (P = 0.018), higher education (P &lt; 0.001), history of hypertension (P &lt; 0.001), and age (P &lt; 0.001), whereas cTnT was more strongly associated with eGFR (P = 0.015). Both cTnI and cTnT were inversely associated with global longitudinal strain and positively associated with LV mass index (LVMI) in analyses adjusted for CV risk factors. The association between cTnI and LVMI was stronger than the association between cTnT and LVMI (P = 0.035). Concentrations of cTnI improved diagnostic accuracy for LV hypertrophy when added to established CV risk factors, but concentrations of cTnT did not improve these models further.

Conclusions

In a large community-based cohort examined with extensive echocardiography, concentrations of cTnI and cTnT are associated with subclinical LV hypertrophy and dysfunction. Concentrations of cTnI appear superior to cTnT in predicting subclinical LV hypertrophy.

Risk factors for atrial fibrillation in hypertrophic cardiomyopathy

Atrial fibrillation is the most common sustained arrhythmia in hypertrophic cardiomyopathy (HCM), occurring in approximately 25% of patients, which is four to six times more common than in similarly aged patients of the general population. Atrial fibrillation is poorly tolerated by HCM patients, largely due to their dependence on atrial systole for left ventricular filling. HCM patients who develop atrial fibrillation have an increased rate of heart failure related mortality and disabling or fatal thromboembolic events, as well as functional deterioration due to progressive heart failure when left untreated. Atrial fibrillation is both common in HCM and may lead to significant morbidity and mortality. Accurate risk stratification for atrial fibrillation in this population is crucial as contemporary treatments are highly successful. In this paper, we review the current understanding of known risk factors for atrial fibrillation, including different imaging-based parameters that assess left atrial structural and functional remodeling, electrocardiographic changes that reflect left atrial electrical remodeling, and a focus on comorbid obstructive sleep apnea, and in addition we review variables that have been reported to be predictive of atrial fibrillation. Last, we summarize the accumulating evidence for HCM patients having an intrinsic atrial myopathy.

The role of human urotensin-II in patients with hypertrophic cardiomyopathy

OBJECTIVE

Hypertrophic cardiomyopathy (HCM) is a genetic condition with the hallmark feature of left ventricular hypertrophy. Human Urotensin-II (hUT-II) is regarded as a cardiovascular autacoid/hormone, and it has cardiac inotropic and hypertrophic properties. Aims of this study were to elucidate the clinical significance of serum hUT-II levels as a potential new biomarker in patients with HCM.

METHODS

This study included 40 HCM patients (60% males and 40% females) and were compared to 30 healthy control subjects (47% males and 53% females. All patients underwent extensive clinical, laboratory, and echocardiographic. Blood samples were taken to test for serum hUT-II levels by commercial ELISA Kit.

RESULTS

Serum hUT-II was significantly higher (p < 0.01) in patients with HCM (15.8 ± 2.1 pmol/L) compared with healthy controls (3.3 ± 1.7 pmol/L). With regard to HCM patient, Serum hUT-II levels were significantly higher in the female with 16.3 ± 1.9 pmol/L than the male with 15.4 ± 2.2 pmol/L (p < 0.05). Among echocardiographic parameters, hUT-II was negatively associated with ejection fraction (r = -0.160, p = 0.324).

CONCLUSION

Results of the first study indicated that serum hUT-II levels were markedly elevated in patients with HCM. Serum hUT-II is a novel biomarker parameter that has clinical use in patients with the severity of LVH.

Sensitive Cardiac Troponins: Could They Be New Biomarkers in Pediatric Pulmonary Hypertension Due to Congenital Heart Disease?

To analyze the role of sensitive cardiac troponin I (scTnI) and high-sensitive troponin T (hscTnT) in the determination of myocardial injury caused by volume and pressure load due to pulmonary hypertension (PH) and to investigate if these markers may be useful in the management of PH in childhood. Twenty-eight patients with congenital heart disease (CHD) with left to right shunt and PH, 29 patients with CHD with left to right shunt but without PH, and 18 healthy children, in total 75 individuals, were included in the study. All cases were aged between 4 and 36 months. Echocardiographic evaluation was performed in all cases, and invasive hemodynamic investigation was performed in 33 cases. Blood samples were obtained from all cases, for the measurement of brain natriuretic peptide (BNP), pro-brain natriuretic peptide (pro-BNP), sensitive cardiac troponin I (scTnI), and high-sensitive troponin T (hscTnT) levels. The mean BNP, pro-BNP, scTnI, and hsTnT levels were statistically significantly higher in patients with PH than in the patients without PH (p < 0.001). A statistically significant positive correlation was determined between pulmonary artery systolic pressure and scTnI and hscTnT levels (r = 0.34 p = 0.01, r = 0.46 p < 0.001, respectively) levels. Pulmonary hypertension determined in congenital heart diseases triggers myocardial damage independently of increased volume or pressure load and resistance, occurring by disrupting the perfusion via increasing ventricular wall tension and the myocardial oxygen requirement. Serum scTnI and hscTnT levels may be helpful markers to determine the damage associated with PH in childhood.

Elevated Level of Troponin but Not N-Terminal Probrain Natriuretic Peptide Is Associated with Increased Risk of Sudden Cardiac Death in Hypertrophic Cardiomyopathy Calculated According to the ESC Guidelines 2014

The aim of this study was to assess the relationship between biomarkers (high-sensitive troponin I [hs-TnI], N-Terminal probrain natriuretic peptide [NT-proBNP]) and calculated 5-year percentage risk score of sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM). Methods. In 46 HCM patients (mean age 39 ± 7 years, 24 males and 22 females), echocardiographic examination, including the stimulating maneuvers to provoke maximized LVOT gradient, had been performed and next ECG Holter was immediately started. After 24 hours, the ECG Holter was finished and the hs-TnI and NT-proBNP have been measured. Patients were divided according to 1/value of both biomarkers (hs-TnI-positive and hs-TnI-negative subgroups) and 2/(NT-proBNP lower and higher subgroup divided by median). Results. In comparison between 19 patients (hs-TnI positive) versus 27 patients (hs-TnI negative), the calculated 5-year percentage risk of SCD in HCM was significantly greater (6.38 ± 4.17% versus 3.81 ± 3.23%, P < 0.05). In comparison between higher NT-proBNP versus lower NT-proBNP subgroups, the calculated 5-year percentage risk of SCD in HCM was not significantly greater (5.18 ± 3.63% versus 4.14 ± 4.18%, P > 0.05). Conclusions. Patients with HCM and positive hs-TnI test have a higher risk of SCD estimated according to SCD calculator recommended by the ESC Guidelines 2014 than patients with negative hs-TnI test.

Biomarkers of cardiovascular stress and fibrosis in preclinical hypertrophic cardiomyopathy

Objective

Sarcomeric gene mutation carriers without overt left ventricular hypertrophy (G+/LVH-) can harbour subclinical changes in cardiovascular structure and function that precede the development of hypertrophic cardiomyopathy (HCM). We sought to investigate if circulating biomarkers of cardiovascular stress and collagen metabolism among G+/LVH- individuals, measured at rest and following exercise provocation, yield further insights into the underlying biology of HCM.

Methods

We studied 76 individuals with overt HCM, 50 G+/LVH- individuals and 41 genotype-negative related controls enrolled in a cross-sectional, multicentre observational study (HCMNet). Biomarkers of cardiac stress (N-terminal pro-B-type natriuretic peptide, NT-proBNP; high-sensitivity troponin I, hsTnI; soluble ST2) and fibrosis (carboxy-terminal propeptide of procollagen type I; C-terminal telopeptide of type I collagen; galectin-3; periostin) were measured.

Results

Individuals with overt HCM had elevated NT-proBNP and hsTnI compared with G+/LVH- subjects and controls at rest, along with an exaggerated increase in NT-proBNP and hsTnI in response to exercise. We found no detectable differences in resting or exercise-provoked biomarker profiles of cardiovascular stress and fibrosis among G+/LVH- individuals compared with healthy controls despite subtle echocardiographic differences in cardiac structure and function.

Conclusion

Dynamic exercise testing exaggerated resting differences in natriuretic peptides and troponin elevations among individuals with overt HCM. In contrast, we found no differences in biomarker profiles of cardiovascular stress and fibrosis among G+/LVH- individuals compared with controls even after maximal exercise provocation. Our findings highlight the need for continued investigation into early phenotypes of sarcomeric gene mutations and the evolution of HCM.

Higher copeptin levels are associated with worse outcome in patients with hypertrophic cardiomyopathy

BACKGROUND

Correlation of increased copeptin levels with various cardiovascular diseases has been described. The clinical use of copeptin levels in patients with hypertrophic cardiomyopathy (HCM) has not been investigated before.

HYPOTHESIS

In this study, we aimed to investigate the prognostic value of copeptin levels in patients with hypertrophic cardiomyopathy (HCM).

METHODS

HCM was defined as presence of left ventricular wall thickness ≥15 mm in a subject without any concomitant disease that may cause left ventricular hypertrophy. Levels of copeptin and plasma N-terminal probrain natriuretic peptide (NT-proBNP) were evaluated prospectively in 24 obstructive HCM patients, 36 nonobstructive HCM patients, and 36 age- and sex-matched control subjects. Blood samples were collected in the morning between 7 and 9 am after overnight fasting. Patients were followed for 24 months. Hospitalization with diagnosis of heart failure/arrhythmia, implantable cardioverter-defibrillator implantation, and cardiac mortality were accepted as adverse cardiac events.

RESULTS

Copeptin and NT-proBNP levels were higher in the HCM group compared with controls (14.1 vs 8.4 pmol/L, P < 0.01; and 383 vs 44 pg/mL, P < 0.01, respectively). Copeptin and NT-proBNP levels were higher in the obstructive HCM subgroup compared with the nonobstructive HCM subgroup (18.3 vs 13.1 pmol/L, P < 0.01; and 717 vs 223 pg/mL, P < 0.01, respectively). In multivariable logistic regression analysis, copeptin and NT-proBNP levels remained as independent predictors of heart failure (P < 0.01 for both) and adverse cardiac events (P < 0.01 for both).

CONCLUSIONS

Copeptin and NT-proBNP levels were significantly higher in patients with obstructive HCM, and higher levels were associated with worse outcome.

Clinical utility of natriuretic peptides and troponins in hypertrophic cardiomyopathy

The diagnosis of hypertrophic cardiomyopathy (HCM) is based on clinical, echocardiographic and in some cases genetic findings. However, prognostication remains limited except in the subset of patients with high-risk indicators for sudden cardiac death. Additional methods are needed for risk stratification and to guide clinical management in HCM. We reviewed the available data regarding natriuretic peptides and troponins in HCM. Plasma levels of natriuretic peptides, and to a lesser extent serum levels of troponins, correlate with established disease markers, including left ventricular thickness, symptom status, and left ventricular hemodynamics by Doppler measurements. As a reflection of left ventricular filling pressure, natriuretic peptides may provide an objective measure of the efficacy of a specific therapy. Both natriuretic peptides and troponins predict clinical risk in HCM independently of established risk factors, and their prognostic power is additive. Routine measurement of biomarker levels therefore may be useful in the clinical evaluation and management of patients with HCM.

Vascular Endothelial Growth Factor Is Associated with the Morphologic and Functional Parameters in Patients with Hypertrophic Cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is mostly autosomal dominant disease of the myocardium, which is characterized by myocardial hypertrophy. Vascular endothelial growth factor (VEGF) is involved in myocyte function, growth, and survival. The aim of study was to analyze the clinical significance of VEGF in structural and functional changes in patient with HCM.

METHODS

In a group of 21 patients with nonobstructive HCM, we assessed serum VEGF and analyzed its association with morphological and functional parameters. Compared to healthy controls, serum VEGF was increased: 199 (IQR: 120.4-260.8) ng/L versus 20 (IQR: 14.8-37.7) ng/L, P < 0.001. VEGF levels were associated with left atrium diameter (r = 0.51, P = 0.01), left ventricle ejection fraction (r = -0.56, P = 0.01), fractional shortening (r = -0.54, P = 0.02), left ventricular mass (r = 0.61, P = 0.03), LV mass index (r = 0.46, P = 0.04), vena cava inferior diameter (r = 0.65, P = 0.01), and peak gradient of tricuspid regurgitation (r = 0.46, P = 0.03).

CONCLUSIONS

Increased VEGF level is associated with structural and functional parameters in patients with HCM and serves as a potential tool for diagnostic process of these patients.

Cardiac Troponins in Dogs and Cats

Cardiac troponins are sensitive and specific markers of myocardial injury. The troponin concentration can be thought of as a quantitative measure of the degree of injury sustained by the heart, however, it provides no information on the cause of injury or the mechanism of troponin release. Conventionally, the cardiac troponins have been used for diagnosis of acute myocardial infarction in humans and have become the gold standard biomarkers for this indication. They have become increasingly recognized as an objective measure of cardiomyocyte status in both cardiac and noncardiac disease, supplying additional information to that provided by echocardiography and ECG. Injury to cardiomyocytes can occur through a variety of mechanisms with subsequent release of troponins. Independent of the underlying disease or the mechanism of troponin release, the presence of myocardial injury is associated with an increased risk of death. As increasingly sensitive assays are introduced, the frequent occurrence of myocardial injury is becoming apparent, and our understanding of its causes and importance is constantly evolving. Presently troponins are valuable for detecting a subgroup of patients with higher risk of death. Future research is needed to clarify whether troponins can serve as monitoring tools guiding treatment, whether administering more aggressive treatment to patients with evidence of myocardial injury is beneficial, and whether normalizing of troponin concentrations in patients presenting with evidence of myocardial injury is associated with reduced risk of death.

Significance and Determinants of Cardiac Troponin I in Patients With Obstructive Hypertrophic Cardiomyopathy

Serum cardiac troponins have been demonstrated to have important clinical implications in patients with hypertrophic cardiomyopathy (HC). However, little is known about their roles in patients with obstructive HC. The aim of this study was to explore the clinical significance and determinants of serum cardiac troponin I (cTnI) in patients with obstructive HC using cardiovascular magnetic resonance imaging. We investigated the relations between serum cTnI levels and clinical, echocardiographic, and cardiovascular magnetic resonance parameters and assessed the determinants of serum cTnI in 149 consecutive patients with obstructive HC. The median level of serum cTnI was 0.019 ng/ml (interquartile range 0.009 to 0.044). CTnI was elevated (≥0.04 ng/ml) in 42 (28%) of the overall cohort. Patients with elevated cTnI had greater maximum wall thickness (p <0.001), larger left ventricular mass index (LVMI, p <0.001), more frequency of left atrium diameter ≥50 mm (p = 0.020), higher plasma values of N-terminal pro-B-type natriuretic peptide (p <0.001), and less hypertension (p = 0.014). Serum cTnI levels were positively correlated with maximum wall thickness (r = 0.444, p <0.001), LVMI (r = 0.556, p <0.001), N-terminal pro-B-type natriuretic peptide (r = 0.305, p <0.001), left ventricular end-diastolic volume index (r = 0.246, p = 0.002), and left ventricular end-systolic volume index (r = 0.272, p = 0.001) but negatively with left ventricular ejection fraction (r = -0.180, p = 0.028). On multivariate analysis, LVMI was independently associated with both elevated cTnI (odds ratio 1.032, p = 0.001) and increasing serum cTnI levels (β = 0.556, p <0.001). In addition, the presence of hypertension was independently related to less likely elevated cTnI (odds ratio 0.307, p = 0.029) and decreasing levels of serum cTnI (β = -0.165, p = 0.015). In conclusion, levels of serum cTnI are elevated in a significant proportion of our patients. Serum cTnI is associated with multiple parameters of disease severity, suggesting its great significance in assessing cardiac remodeling in patients with obstructive HC. Left ventricular hypertrophy, as indicated by LVMI, is the major determinant of serum cTnI levels.

Molecular genetics and pathogenesis of cardiomyopathy

Cardiomyopathy is defined as a disease of functional impairment in the cardiac muscle and its etiology includes both extrinsic and intrinsic factors. Cardiomyopathy caused by the intrinsic factors is called as primary cardiomyopathy of which two major clinical phenotypes are hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM). Genetic approaches have revealed the disease genes for hereditary primary cardiomyopathy and functional studies have demonstrated that characteristic functional alterations induced by the disease-associated mutations are closely related to the clinical types, such that increased and decreased Ca(2+) sensitivities of muscle contraction are associated with HCM and DCM, respectively. In addition, recent studies have suggested that mutations in the Z-disc components found in HCM and DCM may result in increased and decreased stiffness of sarcomere, respectively. Moreover, functional analysis of mutations in the other components of cardiac muscle have suggested that the altered response to metabolic stresses is associated with cardiomyopathy, further indicating the heterogeneity in the etiology and pathogenesis of cardiomyopathy.

Prognostic values of highly sensitive cardiac troponin T and B-type natriuretic peptide for clinical features in hypertrophic obstructive cardiomyopathy: a cross-sectional study

OBJECTIVES

Although B-type natriuretic peptide (BNP) and highly sensitive cardiac troponin T (cTnT) are useful for the evaluation of clinical features in various cardiovascular diseases, there are comparatively few data regarding the utility of these parameters in patients with hypertrophic obstructive cardiomyopathy (HOCM). The goal of this study was to assess the association between BNP, cTnT and clinical parameters in patients with HOCM.

DESIGN

Cross-sectional survey

SETTINGS

The relationship between BNP, cTnT and clinical end points and echocardiographic data was investigated.

PARTICIPANTS

This study included 102 consecutive outpatients with HOCM who were clinically stable.

RESULTS

BNP was significantly associated with both maximum left ventricular (LV) wall thickness (r=0.28; p=0.003), and septal peak early transmitral filling velocity/peak early diastolic mitral annulus velocity (r=0.51; p=0.0001). No statistically significant associations were seen between cTnT and any echocardiographic parameters, but the presence of atrial fibrillation (AF) was associated with a high level of cTnT (p=0.01).

CONCLUSIONS

BNP is useful for monitoring clinical parameters and as a reflection of both LV systolic/diastolic function and increased LV pressure in patients with HOCM. A high level of serum cTnT is associated with the presence of AF.

Relation of highly sensitive cardiac troponin T in hypertrophic cardiomyopathy to left ventricular mass and cardiovascular risk

Elevated cardiac troponin can be seen in patients with left ventricular (LV) hypertrophy and in asymptomatic subjects with a high a priori risk of cardiovascular disease (CVD). In hypertrophic cardiomyopathy (HC) troponin can be detected as well, but little is known about the contribution of LV mass, on the one hand, and the long-term risk of CVD, on the other. In an observational single-center study of 62 patients with HC, without a history of CVD, we assessed the Framingham Heart 10-year risk score (FH10yrs), LV mass index (LVMI) using magnetic resonance imaging, and highly sensitive cardiac troponin T (hs-cTnT). Hs-cTnT (>3 ng/L) was detectable in 74% of patients (46 of 62). Hs-cTnT was elevated in 26% (16 of 62) of patients (ninety-ninth percentile reference limit of 14 ng/L or more). From 3 to 14 ng/L, patients were older, more often had hypertension, and the FH10yrs was higher. Hs-cTnT correlated positively with LVMI (p<0.001) and maximal wall thickness (p<0.001). In addition, LVMI and hypertension were independently associated with increasing hs-cTnT concentrations in linear regression. Using multivariate binary logistic regression, both LVMI and FH10yrs were independently associated with detectable hs-cTnT levels. In contrast, only LVMI was associated with elevated hs-cTnT levels. In conclusion, hs-cTnT was detectable in 3 quarters and elevated in a quarter of our patients with HC. Although detectable hs-cTnT is associated with both LV mass and CVD risk, elevated hs-cTnT relates to LV mass only. This indicates that hypertrophy more than the risk of CVD seems the most important drive for hs-cTnT to occur in these patients.

5'RNA-Seq identifies Fhl1 as a genetic modifier in cardiomyopathy

The transcriptome is subject to multiple changes during pathogenesis, including the use of alternate 5' start-sites that can affect transcription levels and output. Current RNA sequencing techniques can assess mRNA levels, but do not robustly detect changes in 5' start-site use. Here, we developed a transcriptome sequencing strategy that detects genome-wide changes in start-site usage (5'RNA-Seq) and applied this methodology to identify regulatory events that occur in hypertrophic cardiomyopathy (HCM). Compared with transcripts from WT mice, 92 genes had altered start-site usage in a mouse model of HCM, including four-and-a-half LIM domains protein 1 (Fhl1). HCM-induced altered transcriptional regulation of Fhl1 resulted in robust myocyte expression of a distinct protein isoform, a response that was conserved in humans with genetic or acquired cardiomyopathies. Genetic ablation of Fhl1 in HCM mice was deleterious, which suggests that Fhl1 transcriptional changes provide salutary effects on stressed myocytes in this disease. Because Fhl1 is a chromosome X-encoded gene, stress-induced changes in its transcription may contribute to gender differences in the clinical severity of HCM. Our findings indicate that 5'RNA-Seq has the potential to identify genome-wide changes in 5' start-site usage that are associated with pathogenic phenotypes.

A rare case of persistent troponin elevation in a patient with chronic heart failure

We present the case of a woman diagnosed with hypertrophic cardiomyopathy who suffered a myocardial infarction when she was 28 years old, without coronary artery disease on coronary angiography. Two years later, she presented signs of heart failure and left ventricular systolic dysfunction with persistent troponin I elevation, followed by progressive worsening of ventricular dysfunction.

Use of a highly-sensitive cardiac troponin I assay in a screening population for hypertrophic cardiomyopathy: a case-referent study

Background

Hypertrophic cardiomyopathy (HCM) is a genetic condition, and relatives of affected persons may be at risk. Cardiac troponin biomarkers have previously been shown to be elevated in HCM. This study examines the new highly-sensitive cardiac troponin I (hsTnI) assay in a HCM screening population.

Methods

Nested case–control study of consecutive HCM sufferers and their relatives recruited from May 2010 to September 2011. After informed consent, participants provided venous blood samples and clinical and echocardiographic features were recorded. Associations between the natural log (ln) of the contemporary troponin I (cTnI) and hsTnI assays and markers of cardiac hypertrophy were examined. Multiple regression models were fitted to examine the predictive ability of hsTnI for borderline or definite HCM.

Results

Of 107 patients, 24 had borderline and 19 had definite changes of HCM. Both TnI assays showed significant, positive correlations with measures of cardiac muscle mass. After age and sex adjustment, the area under the receiver operator characteristic (AUROC) curve for the outcome of HCM was 0.78, 95% CI [0.65, 0.90], for ln(hsTnI), and 0.66, 95% CI [0.51, 0.82], for ln(cTnI) (p=0.11). Including the hsTnI assay in a multiple-adjusted “screening” model for HCM resulted in a non-significant improvement in both the AUROC and integrated discrimination index.

Conclusions

Both cTnI and hsTnI show a graded, positive association with measures of cardiac muscle mass in persons at risk of HCM. Further studies will be required to evaluate the utility of these assays in ECG- and symptom-based identification of HCM in at-risk families.

Prevalence and determinants of elevated high-sensitivity cardiac troponin T in hypertrophic cardiomyopathy

BACKGROUND

This study was designed to evaluate the prevalence and determinants of increased high-sensitivity cardiac troponin T (hs-cTnT) as a marker of cardiac injury in patients with hypertrophic cardiomyopathy (HCM).

METHODS

A total of 98 consecutive patients with HCM (71.4% males; mean age 51.18 ± 15.47 years) between 2012 and 2013 were evaluated by measuring the level of serum hs-cTnT along with other clinical assessments.

RESULTS

There were 42 (42.9%) patients with a minimum serum hs-cTnT level of 14 ng/L. The mean hs-cTnT level was 12.37 ng/L (6.94-24.26 ng/L). There were significant differences in chest pain New York Heart Association functional class, left ventricular hypertrophy in the surface electrocardiogram, non-sustained ventricular tachycardia in 24-h electrocardiogram-Holter monitoring, left atrial (LA) area index, ratio of peak early (E) transmitral filling velocity to peak early diastolic annular velocity (Ea septal) at the level of the septal mitral annulus (E/Ea septal), maximum left ventricular (LV) wall thickness ≥ 30 mm, and peak LV outflow gradient ≥ 30 mmHg in echocardiography between the patients with hs-cTnT<14 ng/L and those with hs-cTnT ≥ 14 ng/L. However, after multivariate analysis, age, maximum LV wall thickness, LA area index, and E/Ea septal remained as the independent determinants of elevated hs-cTnT in HCM.

CONCLUSIONS

The results demonstrated that hs-cTnT was elevated in a significant number of our HCM patients; therefore, hs-cTnT can be introduced as a valuable marker of myocardial injury in HCM patients.

Cardiac troponin and heart failure in the era of high-sensitivity assays

The Joint European Society of Cardiology-American College of Cardiology Foundation-American Heart Association-World Heart Federation Task Force for the Redefinition of Myocardial Infarction recommends cardiac troponin (cTn)-T as a first-line biomarker, and suggests the use of the 99th percentile of a reference population with acceptable precision (i.e. a coefficient of variance≤10%) as a cut-off for the diagnosis of acute myocardial infarction. Recently developed troponin assays fulfill this analytical precision. While conventional cTnT assays have often been used as a positive or negative categorical variable, stepwise rises in high sensitivity (Hs)-cTnT in patients presenting with chronic heart failure (HF) have been associated with a progressive increase in the incidence of cardiovascular events. Similar observations have been made in the general population. Hs-cTnT at baseline and during follow-up is a powerful predictor of cardiac events in patients with HF and in the general population. Whether it is the ideal biomarker remains to be confirmed, however. We review the potential contributions of TnT assays in the assessment of risk of HF, in HF, and in myocardial diseases that cause HF.

Elevation of serum cardiac troponin I in a cross-sectional cohort of asymptomatic subjects with Friedreich ataxia

BACKGROUND

Friedreich ataxia is an autosomal recessive neurodegenerative disorder characterized by ataxia of all four limbs, dysarthria, areflexia, and cardiomyopathy. At present, baseline values of cardiac troponin I are unknown among Friedreich ataxia subjects.

METHODS

In this study, we evaluated baseline plasma cardiac troponin I levels among a cross-sectional cohort of 49 pediatric and adult Friedreich ataxia subjects without active arrhythmia, chest pain or features of acute coronary syndrome at the time of sampling. We also reviewed baseline electrocardiograms from 45 of these subjects.

RESULTS

Troponin I values were elevated above the 99th percentile population cutoff in 46.9% of all subjects, with 16.3% of asymptomatic subjects having levels typically seen during an acute myocardial infarction. In logistic regression models, younger age and an earlier disease onset predicted higher serum cardiac troponin I values. Only weak correlations were seen between cardiac troponin I values and echocardiogram parameters, including ejection fraction. Additionally, 82.2% of subjects also had abnormal baseline electrocardiograms.

CONCLUSION

The present study demonstrates that both abnormal electrocardiograms and elevated serum cardiac troponin I values may be common baseline characteristics seen in Friedreich ataxia subjects. Further longitudinal studies will allow for a better understanding of the cause and prognostic implications of elevated levels, as well as the clinical utility of serum cardiac troponin I testing in Friedreich ataxia.

Determinants of high-sensitivity troponin T among patients with a noncardiac cause of chest pain

BACKGROUND

It is unknown to what extent noncardiac causes, including renal dysfunction, may contribute to high-sensitivity cardiac troponin T levels.

METHODS

In an observational international multicenter study, we enrolled consecutive patients presenting with acute chest pain to the emergency department. Of 1181 patients enrolled, 572 were adjudicated by 2 independent cardiologists to have a noncardiac cause of chest pain. Multiple linear regression analyses were used to determine the important predictors of log-transformed high-sensitivity cardiac troponin T. Kaplan-Meier curve was used to assess the prognostic significance of high-sensitivity cardiac troponin T>0.014 μg/L (99th percentile).

RESULTS

A total of 88 patients (15%) had high-sensitivity cardiac troponin T>0.014 μg/L. Less than 50% of cardiac troponins could be explained by known cardiac or noncardiac diseases. In decreasing order of importance, age, estimated glomerular filtration rate, hypertension, previous myocardial infarction, and chronic kidney disease (adjusted r(2) 0.44) emerged as significant factors in linear regression analysis to predict high-sensitivity cardiac troponin T. High-sensitivity cardiac troponin T was best explained by a linear curve with age as ≤0.014 μg/L. Patients with high-sensitivity cardiac troponin T levels>0.014 μg/L were at increased risk for all-cause mortality (hazard ratio 3.0; 95% confidence interval, 0.8-10.6; P=.02) during follow-up.

CONCLUSION

Among the known covariates, age and not renal dysfunction is the most important determinant of high-sensitivity cardiac troponin T. Because known cardiac and noncardiac factors, including renal dysfunction, explain less than 50% of high-sensitivity cardiac troponin T levels among patients with a noncardiac cause of chest pain, unknown or underestimated cardiac involvement during the acute presenting condition seems to be the major cause of elevated high-sensitivity cardiac troponin T.

Volume overload and pressure overload due to left-to-right shunt-induced myocardial injury. - Evaluation using a highly sensitive cardiac Troponin-I assay in children with congenital heart disease-

BACKGROUND

Cardiac troponin I (cTnI) is currently considered to be the most sensitive and specific biochemical marker of acute coronary syndrome and acute myocardial infarction. However, few reports have described the use of cTnI assays for evaluating abnormal hemodynamic load in children with congenital heart disease (CHD). It was hypothesized that significant hemodynamic overload due to a left-to-right shunt induces myocardial injury.

METHODS AND RESULTS

A highly sensitive cTnI assay was used to measure the serum cTnI levels in 30 children with atrial septal defect (ASD), 32 children with ventricular septal defect (VSD), and 350 healthy children. Cardiac catheterization was performed in the children with ASD and VSD to determine the ratio of pulmonary to systemic blood flow, the ratio of pulmonary to systemic arterial pressure (Pp/Ps), the pulmonary vascular resistance index, and the right and left ventricular end-diastolic volume. Serum cTnI levels in both the ASD and VSD children were significantly higher than those in healthy children (P<0.05 and P<0.01, respectively). Furthermore, serum cTnI levels significantly correlated with Pp/Ps (r=0.745, P<0.001) in VSD children.

CONCLUSIONS

Significant volume and pressure overload due to a left-to-right shunt induce myocardial injury and might eventually cause irreversible myocardial remodeling in children with CHD. The serum cTnI level is a useful biomarker for evaluating myocardial damage associated with pulmonary hypertension in VSD children.

Perioperative serum troponin I levels are associated with higher risk for atrial fibrillation in patients undergoing coronary artery bypass graft surgery

Atrial fibrillation (AF) remains a frequent complication after coronary artery bypass graft surgery (CABG). We evaluate the association of AF occurrence and serum cardiac troponin I (cTnI) levels in the early postoperative period after CABG. Between April 2009 and January 2010, 95 consecutive patients with sinus rhythm who underwent CABG were evaluated. The patients were divided into two groups according to their postoperative rhythms: sinus rhythm group (SR) and AF group (AF). Demographic, clinical variables, and troponin I were evaluated at the pre- and postoperative times. There were no clinical or demographic differences between the two groups. The postoperative troponin I in the SR group was lower than that in the AF group (0.66 ± 1.62 vs. 2.07 ± 5.01 ng/ml; P = 0.029). Using the receiver operating characteristic curves was found as the best cut-off value to predict AF occurrence at the value of 0.901 ng/ml. Using this value of cTnI, a sensitivity of 60% and a specificity of 87% for AF onset prediction were observed. The cTnI serum levels at the postoperative period after CABG were higher in patients who subsequently developed AF. The cut-off value of 0.901 ng/ml is useful for prediction and preventive therapeutic actions.

Serum levels of high-sensitivity troponin T: a novel marker for cardiac remodeling in hypertrophic cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is characterized by inappropriate hypertrophy, small-vessel coronary artery disease, myocyte disarray, and increased interstitial fibrosis. High-sensitivity troponin T (hs-TnT) could be a reliable indicator of myocardial remodeling, a proposed prognostic marker in HCM. Therefore we hypothesized that increased hs-TnT levels are related to different variables associated with myocardial remodeling, such as the presence of fibrosis assessed with cardiac magnetic resonance imaging (MRI).

METHODS AND RESULTS

We included 95 hemodynamically stable HCM patients, 72 male, aged 45.7 ± 14.2 years, and 45 healthy control subjects with similar age and gender. A complete history and clinical examination was performed, including 12-lead electrocardiogram (ECG), echocardiography, 24-hour ECG-Holter monitoring, symptom-limited treadmill exercise test, and late gadolinium enhancement in cardiac MRI. Risk factors for sudden death were evaluated. A blinded cardiac MRI was performed with late gadolinium enhancement study. Serum hs-TnT levels were assayed. A high proportion (42%) of hemodynamically stable patients studied showed increased levels of hs-TnT. The hs-TnT levels were raised in patients with severe dyspnea: New York Heart Association (NYHA) functional class ≥3 (P = .020), outflow obstruction (P = .013), systolic dysfunction (P = .037), abnormal blood pressure response (P = .036), and presence of gadolinium enhancement (P = .021). The hs-TnT levels correlated positively with the maximum left ventricular wall thickness (r = 0.47; P < .001), left atrial diameter (r = 0.36, P = .014), and outflow gradient (r = 0.28; P = .008).

CONCLUSIONS

A high proportion of hemodynamically stable patients show increased levels of hs-TnT. We observed that raised hs-TnT serum levels are associated with different conditions related to the severity of the disease.

Prognostic usefulness of circulating high-sensitivity troponin T in aortic stenosis and relation to echocardiographic indexes of cardiac function and anatomy

The new high-sensitivity cardiac troponin T (hs-cTnT) assay seems to provide important prognostic information in patients with stable cardiovascular disease. To understand the merit of hs-cTnT more closely in stable cardiovascular disease, we performed extensive echocardiographic characterization of 57 patients with aortic stenosis and myocardial hypertrophy and related hs-cTnT levels to prognosis and echocardiographic indexes of myocardial structure and function. The hs-cTnT levels were above the assay's detection limit in all patients, correlated with echocardiographic indexes of structure and function, most notably with left ventricular mass, and demonstrated prognostic utility of similar strength as N-terminal pro-B-type natriuretic peptide. In conclusion, these findings indicate that hs-cTnT may provide prognostic information in patients with aortic stenosis, and that left ventricular mass is an important determinant of TnT levels in stable patients as measured by the new highly sensitive assay.