Variables Associated With Contrast-Enhanced Cardiovascular Magnetic Resonance in Hypertrophic Cardiomyopathy: Clinical Implications

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.

Cardiopulmonary Exercise Test in Patients with Hypertrophic Cardiomyopathy: A Systematic Review and Meta-Analysis

BACKGROUND

Patients with chronic diseases frequently adapt their lifestyles to their functional limitations. Functional capacity in Hypertrophic Cardiomyopathy (HCM) can be assessed by stress testing. We aim to review and analyze the available data from the literature on the value of Cardiopulmonary Exercise Test (CPET) in HCM. Objective measurements from CPET are used for evaluation of patient response to traditional and new developing therapeutic measurements.

METHODS

A systematic review of the literature was conducted in PubMed, Web of Science and Cochrane in Mar-20. The original search yielded 2628 results. One hundred and two full texts were read after the first screening, of which, 69 were included for qualitative synthesis. Relevant variables to be included in the review were set and 17 were selected, including comorbidities, body mass index (BMI), cardiac-related symptoms, echocardiographic variables, medications and outcomes.

RESULTS

Study sample consisted of 69 research articles, including 11,672 patients (48 ± 14 years old, 65.9%/34.1% men/women). Treadmill was the most common instrument employed (n = 37 studies), followed by upright cycle-ergometer (n = 16 studies). Mean maximal oxygen consumption (VO2max) was 22.3 ± 3.8 mL·kg^-1·min^-1. The highest average values were observed in supine and upright cycle-ergometer (25.3 ± 6.5 and 24.8 ± 9.1 mL·kg^-1·min^-1; respectively). Oxygen consumption in the anaerobic threshold (ATVO2) was reported in 18 publications. Left ventricular outflow tract gradient (LVOT) > 30 mmHg was present at baseline in 31.4% of cases. It increased to 49% during exercise. Proportion of abnormal blood pressure response (ABPRE) was higher in severe (>20 mm) vs. mild hypertrophy groups (17.9% vs. 13.6%, p < 0.001). Mean VO2max was not significantly different between severe vs. milder hypertrophy, or for obstructive vs. non-obstructive groups. Occurrence of arrhythmias during functional assessment was higher among younger adults (5.42% vs. 1.69% in older adults, p < 0.001). Twenty-three publications (9145 patients) evaluated the prognostic value of exercise capacity. There were 8.5% total deaths, 6.7% cardiovascular deaths, 3.0% sudden cardiac deaths (SCD), 1.2% heart failure death, 0.6% resuscitated cardiac arrests, 1.1% transplants, 2.6% implantable cardioverter defibrillator (ICD) therapies and 1.2 strokes (mean follow-up: 3.81 ± 2.77 years). VO2max, ATVO2, METs, % of age-gender predicted VO2max, % of age-gender predicted METs, ABPRE and ventricular arrhythmias were significantly associated with major outcomes individually. Mean VO2max was reduced in patients who reached the combined cardiovascular death outcome compared to those who survived (-6.20 mL·kg^-1·min^-1; CI 95%: -7.95, -4.46; p < 0.01).

CONCLUSIONS

CPET is a valuable tool and can safely perform for assessment of physical functional capacity in patients with HCM. VO2max is the most common performance measurement evaluated in functional studies, showing higher values in those based on cycle-ergometer compared to treadmill. Subgroup analysis shows that exercise intolerance seems to be more related to age, medication and comorbidities than HCM phenotype itself. Lower VO2max is consistently seen in HCM patients at major cardiovascular risk.

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.

Preoperative NT-proBNP Predicts Midterm Outcome After Septal Myectomy

Background

The prognostic value of N‐terminal pro–brain natriuretic peptide (NT‐proBNP) in patients with hypertrophic cardiomyopathy who underwent septal myectomy has not been well studied.

Methods and Results

We retrospectively evaluated NT‐proBNP levels in 758 patients (46.1±13.8 years; median follow‐up, 936 days) who underwent septal myectomy in our center between March 2011 and April 2018. The median NT‐proBNP level was 1450.5 (interquartile range 682.6‐2649.5) pg/mL. Overall, 22 (2.9%) patients died during follow‐up; of these, 86.4% were cardiovascular deaths. The 3‐year survival free from all‐cause mortality by tertile was 95.2% (95% CI 91.1% to 97.4%; NT‐proBNP >2080 pg/mL), 98.3% (95% CI 94.6% to 99.5%; NT‐proBNP, 947‐2080 pg/mL), and 99.2% (95% CI, 94.4% to 99.9%; NT‐proBNP <947 pg/mL). The 3‐year survival rate free from cardiovascular mortality by tertiles was 95.2% in the highest tertile, 98.8% in the middle tertile, and 99.2% in the lowest tertile. Cox regression analysis indicated that Ln(NT‐proBNP) was a significantly independent predictor of all‐cause mortality (hazard ratio 2.380, 95% CI 1.356‐4.178, P=0.003) and cardiovascular mortality (hazard ratio 2.788, 95% CI 1.450‐5.362, P=0.002). In addition, concomitant coronary artery bypass grafting for coronary artery disease was also an independent predictor of cardiovascular mortality (hazard ratio 5.178, 95% CI 1.597‐16.789, P=0.006).

Conclusions

Increased preoperative NT‐proBNP level is a strong predictor of midterm mortality in patients undergoing septal myectomy.

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.

Predictive Values of N-Terminal Pro-B-Type Natriuretic Peptide and Cardiac Troponin I for Myocardial Fibrosis in Hypertrophic Obstructive Cardiomyopathy

Background

Both high-sensitivity cardiac troponin T and B-type natriuretic peptide are useful in detecting myocardial fibrosis, as determined by late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR), in patients with non-obstructive hypertrophic cardiomyopathy. However, their values to predict myocardial fibrosis in hypertrophic obstructive cardiomyopathy (HOCM) remain unclear. We investigated the role of N-Terminal Pro-B-Type Natriuretic Peptide (NT-proBNP) and cardiac troponin I (cTnI) to identify LGE-CMR in patients with HOCM.

Methods

Peripheral concentrations of NT-proBNP and cTnI were determined in patients with HOCM (n = 163; age = 47.2 ± 10.8 years; 38.7% females). Contrast-enhanced CMR was performed to identify and quantify myocardial fibrosis.

Results

LGE was detected in 120 of 163 patients (73.6%). Patients with LGE had significantly higher levels of NT-proBNP and cTnI than those without LGE (1386.2 [904.6–2340.8] vs. 866.6 [707.2–1875.2] pmol/L, P = 0.003; 0.024 [0.010–0.049] vs. 0.010 [0.005–0.021] ng/ml, P <0.001, respectively). The extent of LGE was positively correlated with log cTnI (r = 0.371, P <0.001) and log NT-proBNP (r = 0.211, P = 0.007). On multivariable analysis, both log cTnI and maximum wall thickness (MWT) were independent predictors of the presence of LGE (OR = 3.193, P = 0.033; OR = 1.410, P < 0.001, respectively), whereas log NT-proBNP was not. According to the ROC curve analysis, combined measurements of MWT ≥21 mm and/or cTnI ≥0.025ng/ml indicated good diagnostic performance for the presence of LGE, with specificity of 95% or sensitivity of 88%.

Conclusions

Serum cTnI is an independent predictor useful for identifying myocardial fibrosis, while plasma NT-proBNP is only associated with myocardial fibrosis on univariate analysis. Combined measurements of serum cTnI with MWT further improve its value in detecting myocardial fibrosis in patients with HOCM.

Increased extent of myocardial fibrosis in genotyped hypertrophic cardiomyopathy with ventricular tachyarrhythmias

BACKGROUND

Occurrence of malignant ventricular tachyarrhythmias such as ventricular tachycardia and fibrillation (VT/VF) in hypertrophic cardiomyopathy (HCM) can be related to the extent of myocardial fibrosis. Although late gadolinium enhancement (LGE) on cardiovascular magnetic resonance (CMR) imaging has been used to detect myocardial fibrosis, few data exist regarding relationships between CMR-determined myocardial fibrosis and VT/VF in genotyped HCM populations.

OBJECTIVE

We retrospectively investigated whether the extent of LGE can be increased in HCM patients with VT/VF compared to those without VT/VF in the genotyped HCM population.

METHODS AND RESULTS

We studied 35 HCM patients harboring sarcomere gene mutations (TNNI3=22, MYBPC3=12, MYH7=1) who underwent both CMR imaging and 24-h ambulatory electrocardiographic monitoring. VT/VF were identified in 6 patients (2 men, mean age 55.0 years). The extent of LGE was significantly increased in patients with VT/VF (n=6) compared with those without VT/VF (n=29) (18.6±14.4% vs. 8.3±11.4%, p=0.04), although the LGE extent was not an independent predictor for the occurrence of VT/VF. Applying a cut-off point ≥3.25%, episodes of VT/VF were identified with a sensitivity of 100%, specificity of 51.7%, positive predictive value of 30%, negative predictive value of 100%, and the area under the curve of 0.767 (95% confidence interval: 0.590-0.944).

CONCLUSION

These results demonstrate that myocardial fibrosis determined by CMR imaging may be increased in genotyped HCM patients with episodes of VT/VF. A further prospective study will be needed to clarify the association between the LGE extent and arrhythmic events in HCM patients harboring sarcomere gene mutations.

Determinants of peak oxygen uptake in patients with hypertrophic cardiomyopathy: a single-center study

Most patients with hypertrophic cardiomyopathy (HCM) usually complain of a reduced exercise capacity, and several factors have been advocated as possible causes of this clinical feature. The present single-center study was designed to investigate exercise capacity and its main clinical determinants in HCM patients. One hundred ninety seven patients of 223 evaluated underwent a complete clinical assessment, including Doppler echocardiography, cardiopulmonary exercise test (CPET) and, in most cases, cardiac magnetic resonance. The HCM population (male 75 %; age 47 ± 16 years; NYHA class I or II 95 %; left ventricular ejection fraction 61 ± 3 %; resting left ventricular outflow tract gradient ≥30 mmHg 22 %; late gadolinium enhancement presence 58 %) showed slightly reduced mean peak oxygen uptake values (pVO2 75 ± 15 %, 23.2 ± 6.7 ml/kg/min) with a significant reduction of the achieved percentage of peak heart rate reserve (%pHRR 65 ± 20 %). Adopting a pVO2 <80 % cut-off value, 59 % of HCM patients showed a reduced exercise capacity. Age, male gender, left atrial size, chronotropic and systolic blood pressure response, ventilatory efficiency, late gadolinium enhancement presence and β-blocker therapy were independently associated with pVO2 (R (2)-adjusted index 0.738). A %pHRR cut-off value of 74 % appeared to most accurately predict an impaired exercise capacity (area under curve 0.90). A great prevalence of reduced exercise capacity is present in NYHA class I-II HCM patients. Notwithstanding its multifactorial genesis, few parameters might be adopted in identifying this feature. In this context, %pHRR value might represent a reliable and easy-to-obtain tool for the clinical evaluation of HCM patients.

Determining the role of fibrosis in hypertrophic cardiomyopathy

Fibroblast activity within the heart may be considered a basically constructive process. Hyperactivity of fibroblasts, however, may result in the accumulation of extracellular matrix proteins with adverse effects on cardiac structure and function including electrical instability and increased risk of arrhythmogenic cardiac death. The detection of cardiac fibrosis by dedicated imaging techniques, mainly gadolinium-enhanced MRI, holds promise to refine patient management in a variety of cardiac conditions. This review aims to summarize the current knowledge regarding fibrosis in hypertrophic cardiomyopathy.

Usefulness of high-sensitivity cardiac troponin T and brain natriuretic peptide as biomarkers of myocardial fibrosis in patients with hypertrophic cardiomyopathy

Myocardial fibrosis assessed by late gadolinium enhancement cardiac magnetic resonance imaging is associated with cardiovascular events in patients with hypertrophic cardiomyopathy (HC), but few data are available regarding the utility of biomarkers for detecting late gadolinium enhancement. The aim of this study was to examine serum levels of myoglobin, cardiac myosin light chain I, high-sensitivity cardiac troponin T (hs-cTnT), and creatine kinase-MB isoenzyme and plasma levels of brain natriuretic peptide (BNP) in relation to late gadolinium enhancement in 53 patients with HC. Levels of hs-cTnT and BNP were higher in 23 patients with late gadolinium enhancement than in 30 patients without it (p <0.01 for both). An hs-cTnT level ≥0.007 ng/ml or a BNP level ≥70 pg/ml had good diagnostic value for detecting late gadolinium enhancement, with sensitivity of 96% or specificity of 90% with the combination of these 2 biomarkers. The extent of late gadolinium enhancement was correlated with BNP level (p <0.01) but not with hs-cTnT level in 23 patients with HC with late gadolinium enhancement. The increase in the extent of late gadolinium enhancement was related to hs-cTnT level in 8 patients during 22 months of follow-up (p = 0.02). In conclusion, the combination of hs-cTnT and BNP is useful in detecting myocardial fibrosis in patients with HC. The findings of this study indicate that hs-cTnT is a direct marker of ongoing myocardial fibrosis and that BNP is a marker of left ventricular overload partially associated with myocardial fibrosis.

The diagnosis of hypertrophic cardiomyopathy by cardiovascular magnetic resonance

Hypertrophic cardiomyopathy (HCM) is the most common genetic disease of the heart. HCM is characterized by a wide range of clinical expression, ranging from asymptomatic mutation carriers to sudden cardiac death as the first manifestation of the disease. Over 1000 mutations have been identified, classically in genes encoding sarcomeric proteins. Noninvasive imaging is central to the diagnosis of HCM and cardiovascular magnetic resonance (CMR) is increasingly used to characterize morphologic, functional and tissue abnormalities associated with HCM. The purpose of this review is to provide an overview of the clinical, pathological and imaging features relevant to understanding the diagnosis of HCM. The early and overt phenotypic expression of disease that may be identified by CMR is reviewed. Diastolic dysfunction may be an early marker of the disease, present in mutation carriers prior to the development of left ventricular hypertrophy (LVH). Late gadolinium enhancement by CMR is present in approximately 60% of HCM patients with LVH and may provide novel information regarding risk stratification in HCM. It is likely that integrating genetic advances with enhanced phenotypic characterization of HCM with novel CMR techniques will importantly improve our understanding of this complex disease.

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.

Plasma levels of von Willebrand factor are increased in patients with hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is characterised by inappropriate hypertrophy, small-vessel coronary artery disease, myocyte disarray and increased interstitial fibrosis. Microvascular dysfunction is a common finding in HCM and its extent has been proposed as an important prognostic marker. Plasma von Willebrand factor (vWf) is an established marker of endothelial damage or dysfunction; however it has scarcely been studied in HCM. We hypothesised that vWf could be raised in patients with HCM and be related to different variables associated with severity of HCM.

METHODS

We included 124 HCM patients, 93 males, aged 48+/-15 years, 59 healthy control subjects with similar age and sex and 20 patients with ischemic heart disease but clinical stability for the last 6 months. A complete history and clinical examination was performed, including 12-lead electrocardiogram, echocardiography, 24 hours ECG-Holter monitoring, and symptom limited treadmill exercise test. Risk factors for sudden death were evaluated. A blinded cardiac MRI was performed with late enhanced study with Gadolinium. Plasma vWf levels were assayed by commercial ELISA.

RESULTS

Patients showed higher levels of vWf (140.0+/-65.0 UI/ml vs 105.0+/-51.0 UI/ml, p<0.001) even after adjusting for ABO blood group. vWf levels were found raised in patients with severe functional class (168.4+/-65.9 UI/mL vs 132.4+/-60.7 UI/mL, p=0.020), atrial fibrillation (175.8+/-69.4 UI/mL vs 133.0+/-59.0 UI/mL, p=0.005), hypertension (161.4+/-60.8 vs 128.9+/-60.5, p=0.010) obstruction (153.9+/-67.9 vs 128.2+/-57.4 UI/mL, p=0.046) and non sustained ventricular tachycardia (159.3+/-59.1 vs 133.0+/-63.0, p=0.049). vWf correlated with age (r:0.26; p=0.006) and obstruction (r:0.22; p=0.021).

CONCLUSIONS

We show, for the first time, patients with HCM present significantly raised levels of vWf. These are associated with different conditions related to the severity of the disease.

Left atrial remodelling in hypertrophic cardiomyopathy: relation with exercise capacity and biochemical markers of tissue strain and remodelling

BACKGROUND

Left atrial remodelling, assessed as left atrial volume (LAV), has been proposed as a good marker of left ventricular diastolic dysfunction. The aim of this study was to analyse the influence of LAV on exercise performance in hypertrophic cardiomyopathy (HCM), and in a subset of subjects, assess the relation of LAV and exercise performance to four biomarkers of disease pathophysiology: matrix metalloproteinase-2 (MMP-2) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) (as indices of tissue remodelling), N-terminal portion of pro B-type natriuretic peptide (NT-pro-BNP) (associated with ventricular dysfunction) and C-reactive protein (CRP, an index of inflammation).

METHODS

We studied 75 consecutive HCM patients (aged 46 +/- 14 years, 56 men) where LAV was calculated assuming the ellipsoid model with two orthogonal planes. LAV was indexed to body surface area. Exercise capacity was evaluated by treadmill exercise test (symptom limited) and assessed with metabolic equivalent units (MET). Basal NT-pro-BNP and CRP levels were measured in 70 patients, whereas MMP-2 and TIMP-1 in 43 patients.

RESULTS

Enlarged LAV was observed in those patients with previous atrial fibrillation (p = 0.016). Mean LAV was greater in patients with impaired functional New York Heart Association (NYHA) class (p < 0.001). LAV correlated with age (Spearman, r: 0.28), higher maximal left ventricular wall thickness (r: 0.32) and raised E/A ratio (r: 0.37) (all p < 0.01). LAV was significantly correlated with NT-pro-BNP values (r: 0.34; p = 0.04), MMP-2 (r: 0.32; p = 0.034), CRP (r: 0.33; p = 0.005) and correlated inversely with MET units (r: -0.39; p < 0.01). In multivariate analysis, MET units were only associated with NT-pro-BNP (p = 0.002) and LAV (p = 0.010).

CONCLUSIONS

Enlarged LAV is associated with impaired functional NYHA class and inversely with treadmill exercise capacity. Enlarged LAV is also associated with NT-pro-BNP, MMP-2 and CRP, perhaps as markers of disease severity and tissue remodelling. Age, LAV and NT-pro-BNP are independent predictors of exercise performance.

Identifying the etiology: a systematic approach using delayed-enhancement cardiovascular magnetic resonance

In patients who have heart failure, treatment and survival are directly related to the cause. Clinically, as a practical first step, patients are classified as having either ischemic or non-ischemic cardiomyopathy, a delineation usually based on the presence or absence of epicardial coronary artery disease. However, this approach does not account for patients with non-ischemic cardiomyopathy who also have coronary artery disease, which may be either incidental or partly contributing to myocardial dysfunction (mixed cardiomyopathy). By allowing direct assessment of the myocardium, delayed-enhancement cardiovascular magnetic resonance (DE-CMR) may aid in addressing these conundrums. This article explores the use of DE-CMR in identifying ischemic and non-ischemic myopathic processes and details a systematic approach to determine the cause of cardiomyopathy.

Biomarkers of pathophysiology in hypertrophic cardiomyopathy: implications for clinical management and prognosis

The study of biomarkers and their signalling pathways has allowed the development of new therapeutic strategies in a range of disorders. The aim of the present systematic review is to provide an overview of different biomarkers in patients with hypertrophic cardiomyopathy that could give some insight into the pathophysiologic mechanism(s) underlying the typical clinical and histological manifestations of the disease. Several pathophysiological models are presented and discussed, including studies that have investigated these biomarkers for diagnostic and prognostic reasons, in relation to disease progression and/or mortality.