The effect of cardiac fibrosis on left ventricular remodeling, diastolic function, and N-terminal pro-B-type natriuretic peptide levels in patients with nonischemic dilated cardiomyopathy

The association of left ventricular histologically verified myocardial fibrosis with pulmonary hypertension in severe aortic stenosis

OBJECTIVES

To evaluate the association between histologically verified left ventricular (LV) myocardial fibrosis (MF) and its bio- and functional markers with pulmonary hypertension (PH) in severe aortic stenosis (AS).

METHODS

About 34 patients with isolated severe AS underwent 2D echocardiography, cardiac magnetic resonance (CMR) imaging, and plasma NT-proBNP evaluation before aortic valve replacement (AVR). LV measurements were analyzed by CMR and LV strain using feature tracking software (Medis Suite QStrain 2.0). Myocardial biopsy sampled at the time of AVR was assessed by a histomorphometric analysis. PH was defined as pulmonary artery systolic pressure (PASP) ⩾ 45 mm Hg.

RESULTS

Patients with severe AS and PH (mean PASP 53 ± 3.7 mm Hg) had higher extent of diffuse MF versus patients without PH (12 (10.4-12.7)% vs 6.6 (4.6-8.2)% (p = 0.00)). The extent of diffuse MF correlated with LV dilatation (r = 0.7, p = 0.02), indices of LV dysfunction (lower ejection fraction (r = -0.6, p < 0.001), global longitudinal (r = -0.5, p = 0.02) and circumferential strain (r = -0.5, p = 0.05), elevated NT-proBNP (r = 0.5, p = 0.005) and elevated PASP (r = 0.6, p < 0.001)). Histological MF > 10% (AUC 94.9%), LV global longitudinal strain > -15.5% (AUC 86.3%), and NT-proBNP > 2090 ng/l (AUC 85.1%) were independent predictors of PH in severe AS.

CONCLUSIONS

The extent of diffuse myocardial fibrosis in combination with reduced longitudinal left ventricular strain and increased plasma levels of NT-proBNP relates to pulmonary hypertension in severe aortic stenosis.

Programming by Methyl Donor Deficiency during Pregnancy and Lactation Produces Cardiomyopathy in Adult Rats Subjected to High Fat Diet

SCOPE

Vitamin B12 and folate (methyl donors) deficiency is frequent during pregnancy. Experimental rat models with methyl donor deficit during pregnancy and lactation (Initial methyl donor deficit (iMDD)) produce impaired myocardium fatty acid oxidation and mitochondrial energy metabolism at weaning.

METHODS AND RESULTS

The consequences of iMDD on heart of rat pups under normal diet after weaning and high fat diet (HF) between day (D) 50 and D185 are investigated. iMDD/HF induces increased histological fibrosis and increased B-type natriuretic peptide blood level. Inflammation is evidenced by increased protein expression of NFkB, Caspase1, and IL1β and fibrosis by increased expression of αSMA, col1a1, and col1a2 in females, but not in males. Fibrosis is related to increased angiotensin at D50 and D185 and increased protein expression of TGFB1 and AT1 angiotensin receptors at D185. The limited fibrosis in males is consistent with increased expression of AT2, the antagonist receptor of AT1. The increased expression of GLUT4 and decreased expression of PGC1α and PPARα reflect a shift from fatty acid oxidation to glycolysis.

CONCLUSION

Developmental programming by iMDD produces cardiomyopathy in female offspring exposed to HF. The cardiomyopathy is linked to inflammation and fibrosis through angiotensin-AT2 and TGFB1 pathways and alteration of energy metabolism.

Lack of Relationship between Fibrosis-Related Biomarkers and Cardiac Magnetic Resonance-Assessed Replacement and Interstitial Fibrosis in Dilated Cardiomyopathy

The relationship between circulating fibrosis-related molecules and magnetic resonance-assessed cardiac fibrosis in dilated cardiomyopathy (DCM) is poorly understood. To compare circulating biomarkers between DCM patients with high and low fibrosis burdens, we performed a prospective, single-center, observational study. The study population was composed of 100 DCM patients (87 male, mean age 45.2 ± 11.8 years, mean ejection fraction 29.7% ± 10.1%). Replacement fibrosis was quantified by means of late gadolinium enhancement (LGE), whereas interstitial fibrosis was assessed via extracellular volume (ECV). Plasma concentrations of cardiotrophin-1, growth differentiation factor-15, platelet-derived growth factor, procollagen I C-terminal propeptide, procollagen III N-terminal propeptide, and C-terminal telopeptide of type I collagen were measured. There were 44% patients with LGE and the median ECV was 27.7%. None of analyzed fibrosis serum biomarkers were associated with the LGE or ECV, whereas NT-proBNP was independently associated with both LGE and ECV, and troponin T was associated with ECV. None of the circulating fibrosis markers differentiated between DCM patients with and without replacement fibrosis, or patients stratified according to median ECV. However, cardiac-specific markers, such as NT-proBNP and hs-TnT, were associated with fibrosis. Levels of circulating markers of fibrosis seem to have no utility in the diagnosis and monitoring of cardiac fibrosis in DCM.

Autophagy inhibitor 3-methyladenine alleviates overload-exercise-induced cardiac injury in rats

Overload-exercise (OE) causes myocardial injury through inducing autophagy and apoptosis. In this study we examined whether an autophagy inhibitor 3-methyladenine (3-MA) could alleviate OE-induced cardiac injury. Rats were injected with 3-MA (15 mg/kg, iv) or saline before subjected to various intensities of OE, including no swim (control), 2 h swim (mild-intensity exercise, MIE), 2 h swim with 2.5% body weight overload (moderate OE; MOE), 5% overload (intensive OE; IOE) or 2.5% overload until exhausted (exhaustive OE; EOE). After OE, the hearts were harvested for morphological and biochemiacal analysis. The cardiac morphology, autophagosomes and apoptosis were examined with H&E staining, transmission electron microscopy and TUNEL analysis, respectively. Autophagy-related proteins to (LC3-II/I and Beclin-1) and apoptosis-related proteins (Bcl-2/Bax) were assessed using Western blotting. Our results showed that compared with the control, MIE did not change the morphological structures of the heart tissues that exhibited intact myocardial fibers and neatly arranged cardiomyocytes. However, IOE resulted in irregular arrangement of cardiomyocytes and significantly increased width of cardiomyocytes, whereas EOE caused more swollen and even disrupted cardiomyocytes. In parallel with the increased OE intensity (MOE, IOE, EOE), cardiomyocyte autophagy and apoptosis became more and more prominent, evidenced by the increasing number of autophagosomes and expression levels of LC3-II/I and Beclin-1 as well as the increasing apoptotic cells and decreasing Bcl-2/Bax ratio. 3-MA administration significantly attenuated OE-induced morphological changes of cardiomyocytes as well as all the autophagy- and apoptosis-related abnormalities in MOE, IOE and EOE rats. Thus, the autophagy inhibitor 3-MA could alleviate OE-induced heart injury in rats.

Heat shock transcription factor 1 protects against pressure overload-induced cardiac fibrosis via Smad3

Abstract

Fibrotic cardiac muscle exhibits high stiffness and low compliance which are major risk factors of heart failure. Although heat shock transcription factor 1 (HSF1) was identified as an intrinsic cardioprotective factor, the role that HSF1 plays in cardiac fibrosis remains unclear. Our study aims to investigate the role of HSF1 in pressure overload-induced cardiac fibrosis and the underlying mechanism. HSF1 phosphorylation was significantly downregulated in transverse aortic constriction (TAC)-treated mouse hearts and mechanically stretched cardiac fibroblasts (cFBs). HSF1 transgenic (TG) mice, HSF1 deficient heterozygote (KO) mice, and their wild-type littermates were subjected to sham or TAC surgery for 4 weeks. HSF1 overexpression significantly attenuated pressure overload-induced cardiac fibrosis and dysfunction. Conversely, HSF1 KO mice showed deteriorated fibrotic response and cardiac dysfunction upon TAC. Moreover, we uncovered that overexpression of HSF1 protected against fibrotic response of cFBs to pressure overload. Mechanistically, we observed that the phosphorylation and the nuclear distribution of the Smad family member 3 (Smad3) were significantly decreased in HSF1-overexpressing mouse hearts, while being greatly increased in HSF1 KO mouse hearts upon TAC, compared to the control hearts, respectively. Similar alteration of Smad3 phosphorylation and nuclear distribution were found in isolated mouse cardiac fibroblasts and mechanically stretched cFBs. Constitutively active Smad3 blocked the anti-fibrotic effect of HSF1 in cFBs. Furthermore, we found a direct binding of phosphorylated HSF1 and Smad3, which can be suppressed by mechanical stress. In conclusion, the present study demonstrated for the first time that HSF1 acts as a novel negative regulator of cardiac fibrosis by blocking Smad3 activation.

Key messages

HSF1 activity is decreased in fibrotic hearts.

HSF1 overexpression attenuates pressure overload-induced cardiac fibrosis and dysfunction.

Deficiency of HSF1 deteriorates fibrotic response and cardiac dysfunction upon TAC.

HSF1 inhibits phosphorylation and nuclear distribution of Smad3 via direct binding to Smad3.

Active Smad3 blocks the anti-fibrotic effect of HSF1.

Electronic supplementary material

The online version of this article (doi:10.1007/s00109-016-1504-2) contains supplementary material, which is available to authorized users.

Prognostic significance of myocardial extracellular volume fraction in nonischaemic dilated cardiomyopathy

AIMS

In nonischaemic dilated cardiomyopathy (NICM), replacement myocardial fibrosis as detected by late gadolinium enhancement (LGE) at cardiovascular magnetic resonance (CMR) is associated with poor prognosis. We investigated the as-yet unexplored prognostic significance of interstitial fibrosis in NICM, using T1-mapping CMR.

METHODS

Eighty-nine NICM patients (63 men, age 59 ± 14 years) with left ventricular systolic dysfunction (ejection fraction 41 ± 13%) underwent comprehensive clinical and CMR evaluation, with extracellular volume fraction (ECV) estimation from pre and postcontrast T1 mapping. Fifteen healthy individuals (11 men, mean age 52 ± 11 years) were used as controls. The end-point was a composite of cardiovascular death, hospitalization for heart failure and appropriate defibrillator intervention.

RESULTS

Myocardial ECV was higher in NICM patients (0.31 ± 0.05) than controls (0.25 ± 0.04, P < 0.01). In NICM patients, myocardial ECV correlated with left ventricular ejection fraction (R = 0.13), LGE extent (R = 0.17), Doppler E/E' (R = 0.17) and ventricular tachycardias (R = 0.21) at 24-h ECG monitoring (P < 0.05 for all). During a median follow-up of 24 months (interquartile range 12-42 months), 12 events occurred and higher myocardium ECV was independently associated with the occurrence of the composite end-point (P < 0.01).

CONCLUSION

In NICM patients, myocardial ECV was increased compared with normal individuals, likely reflecting extracellular matrix remodelling and collagen deposition, and resulted an independent prognostic predictor beyond all other conventional clinical, electrocardiographic and echocardiographic parameters.

Transcutaneous electrical acupoint stimulation alleviates adverse cardiac remodeling induced by overload training in rats

Electroacupuncture has been shown previously to alleviate cardiac ischemia-reperfusion injury. Overload training (OT) exercise can result in profound cardiac damage and remodeling. In this study, we aimed to examine whether transcutaneous electrical acupoint stimulation (TEAS), a novel noninvasive and low-risk alternative to electroacupuncture, could counteract short-term OT-induced cardiac remodeling, fibrosis, autophagy, and apoptosis. Sixty rats were randomly divided into eight groups (n = 7 or 8/group): control, regular exercise, OT, OT plus low-, moderate- or high-frequency TEAS preconditioning, OT plus moderate-frequency TEAS postconditioning, or transcutaneous electrical nonacupoint stimulation (TENAS) preconditioning. The cardiac weight index (heart weight/body weight) was determined. Left ventricular morphology was examined by hematoxylin and eosin staining. Cardiac fibrosis and apoptosis were determined by Masson's trichrome and TUNEL staining, respectively. The presence of autophagosomes was observed by transmission electron microcopy. The expressions of autophagic markers (LC3 II/I and Beclin-1) were determined by Western blot. The results showed that 1) OT induced adverse cardiac structure changes but did not affect the cardiac weight index; 2) OT increased cardiac fibrosis and apoptosis and induced autophagosome formation with upregulated LC3 II/I and Beclin-1 expression; 3) TEAS preconditioning effectively alleviated OT-induced cardiac structure changes, fibrosis, apoptosis, and autophagy; 4) TEAS preconditioning produced better protective effects than TEAS postconditioning or TENAS preconditioning. Our results demonstrate that TEAS preconditioning protects the heart from OT-induced cardiac injury/remodeling, probably by inhibition of fibrosis, autophagy, and apoptosis.

Relationship between Myocardial Extracellular Space Expansion Estimated with Post-Contrast T1 Mapping MRI and Left Ventricular Remodeling and Neurohormonal Activation in Patients with Dilated Cardiomyopathy

OBJECTIVE

Post-contrast T1 values are closely related to the degree of myocardial extracellular space expansion. We determined the relationship between post-contrast T1 values and left ventricular (LV) diastolic function, LV remodeling, and neurohormonal activation in patients with dilated cardiomyopathy (DCM).

MATERIALS AND METHODS

Fifty-nine patients with DCM (mean age, 55 ± 15 years; 41 males and 18 females) who underwent both 1.5T magnetic resonance imaging and echocardiography were enrolled. The post-contrast 10-minute T1 value was generated from inversion time scout images obtained using the Look-Locker inversion recovery sequence and a curve-fitting algorithm. The T1 sample volume was obtained from three interventricular septal points, and the mean T1 value was used for analysis. The N-Terminal pro-B-type natriuretic peptide (NT-proBNP) level was measured in 40 patients.

RESULTS

The mean LV ejection fraction was 24 ± 9% and the post-T1 value was 254.5 ± 46.4 ms. The post-contrast T1 value was significantly correlated with systolic longitudinal septal velocity (s'), peak late diastolic velocity of the mitral annulus (a'), the diastolic elastance index (Ed, [E/e']/stroke volume), LV mass/volume ratio, LV end-diastolic wall stress, and LV end-systolic wall stress. In a multivariate analysis without NT-proBNP, T1 values were independently correlated with Ed (β = -0.351, p = 0.016) and the LV mass/volume ratio (β = 0.495, p = 0.001). When NT-proBNP was used in the analysis, NT-proBNP was independently correlated with the T1 values (β = -0.339, p = 0.017).

CONCLUSION

Post-contrast T1 is closely related to LV remodeling, diastolic function, and neurohormonal activation in patients with DCM.

Pathophysiological links, echocardiographic characteristics, and clinical implications of QRS morphology in patients with dilated cardiomyopathy

Heart failure is an important clinical problem worldwide. There is great interest in evaluating the relationship between electrocardiographic variations and dilated cardiomyopathy (DCM) since it has been used as a predictor of increased morbidity and mortality. The presence of fragmentation in the QRS complexes on 12-lead electrocardiogram (ECG) was reported as a marker of depolarization abnormality in patients with DCM. Previous studies have investigated the relation between QRS morphology and DCM. QRS morphology and duration are associated with clinical deterioration and increased mortality in patients with DCM. Although surface ECG provides valuable information on prognosis of these patients, echocardiographic methods have been used for further investigation of patients with DCM. The aim of the present review is to provide an overview of the pathophysiological links, echocardiographic characteristics and clinical implications of QRS morphology in patients with DCM.

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.

Late gadolinium enhancement on cardiac magnetic resonance predicts adverse cardiovascular outcomes in nonischemic cardiomyopathy: a systematic review and meta-analysis

BACKGROUND

Late gadolinium enhancement (LGE) by cardiac MR (CMR) is a predictor of adverse cardiovascular outcomes in patients with nonischemic cardiomyopathy (NICM). However, these findings are limited by single-center studies, small sample sizes, and low event rates. We performed a meta-analysis to evaluate the prognostic role of LGE by CMR (LGE-CMR) imaging in patients with NICM.

METHODS AND RESULTS

PubMed, Cochrane CENTRAL, and EMBASE were searched for studies looking at the prognostic value of LGE-CMR in patients with NICM. The primary end points included all-cause mortality, heart failure hospitalization, and a composite end point of sudden cardiac death (SCD) or aborted SCD. Pooling of odds ratios was performed using a random-effect model, and annualized event rates were assessed. Data were included from 9 studies with a total of 1488 patients and a mean follow-up of 30 months. Patients had a mean age of 52 years, 67% were men, and the average left ventricular ejection fraction was 37% on CMR. LGE was present in 38% of patients. Patients with LGE had increased overall mortality (odds ratio, 3.27; P<0.00001), heart failure hospitalization (odds ratio, 2.91; P=0.02), and SCD/aborted SCD (odds ratio, 5.32; P<0.00001) compared with those without LGE. The annualized event rates for mortality were 4.7% for LGE+ subjects versus 1.7% for LGE- subjects (P=0.01), 5.03% versus 1.8% for heart failure hospitalization (P=0.002), and 6.0% versus 1.2% for SCD/aborted SCD (P<0.001).

CONCLUSIONS

LGE in patients with NICM is associated with increased risk of all-cause mortality, heart failure hospitalization, and SCD. Detection of LGE by CMR has excellent prognostic characteristics and may help guide risk stratification and management in patients with NICM.

Activation of cardiac fibroblasts by ethanol is blocked by TGF-β inhibition

BACKGROUND

Alcohol abuse is the second leading cause of dilated cardiomyopathy, a disorder specifically referred to as alcoholic cardiomyopathy (ACM). Rodent and human studies have revealed cardiac fibrosis to be a consequence of ACM, and prior studies by this laboratory have associated this occurrence with elevated transforming growth factor-beta (TGF-β) and activated fibroblasts (myofibroblasts). To date, there have been no other studies to investigate the direct effect of alcohol on the cardiac fibroblast.

METHODS

Primary rat cardiac fibroblasts were cultured in the presence of ethanol (EtOH) and assayed for fibroblast activation by collagen gel contraction, alpha-smooth muscle actin (α-SMA) expression, migration, proliferation, apoptosis, collagen I and III, and TGF-β expression. The TGF-β receptor type 1 inhibitor compound SB 431542 and a soluble recombinant TGF-βII receptor (RbII) were used to assess the role of TGF-β in the response of cardiac fibroblasts to EtOH.

RESULTS

Treatment for cardiac fibroblasts with EtOH at concentrations of 100 mg/dl or higher resulted in fibroblast activation and fibrogenic activity after 24 hours including an increase in contraction, α-SMA expression, migration, and expression of collagen I and TGF-β. No changes in fibroblast proliferation or apoptosis were observed. Inhibition of TGF-β by SB 431542 and RbII attenuated the EtOH-induced fibroblast activation.

CONCLUSIONS

EtOH treatment directly promotes cardiac fibroblast activation by stimulating TGF-β release from fibroblasts. Inhibiting the action of TGF-β decreases the fibrogenic effect induced by EtOH treatment. The results of this study support TGF-β to be an important component in cardiac fibrosis induced by exposure to EtOH.

Coronary flow reserve as a link between diastolic and systolic function and exercise capacity in heart failure

AIMS

In heart failure, a reduced exercise capacity is the prevailing symptom and an important prognostic marker of future outcome. The purpose of the study was to assess the relation of coronary flow reserve (CFR) to diastolic and systolic function in heart failure and to determine which are the limiting factors for exercise capacity.

METHODS AND RESULTS

Forty-seven patients with left ventricular ejection fraction (LVEF) <35 [median LVEF 31 (inter-quartile range 26-34)] underwent cardiorespiratory exercise test with measurement of VO2 peak, a dual X-ray absorptiometry scan for body composition, and a full echocardiography with measurement of LVEF using the biplane Simpson model, mitral inflow velocities, and pulsed wave tissue Doppler. Peak coronary flow velocity (CFV) was measured in the LAD, using pulsed-wave Doppler. CFR was calculated as the ratio between peak CFV at rest and during 2 min of adenosine stress. Fat-free-mass-adjusted VO2 peak correlated significantly with CFR (r = 0.48, P = 0.002), E/e' (r = -0.35, P = 0.02), and s' (r = 0.45, P = 0.001) but not with LVEF (r = 0.23, P = 0.11). CFR correlated significantly with E/e' (r = -0.46, P = 0.003) and s' (r = 0.36, P = 0.02), but not with LVEF (r = 0.18, P = 0.26). When adjusting for CFR in a multivariable linear model, s' but not E/e' remained independently associated with VO2 peak.

CONCLUSION

In this group of heart failure patients, VO2 peak was correlated with CFR, E/e', and s' but not with traditional measures of systolic function. CFR remained associated with VO2 peak independently of diastolic and systolic function and is likely to be a limiting factor in functional capacity of heart failure patients.

Association of left ventricular diastolic dysfunction with elevated NT-proBNP in type 2 diabetes mellitus patients with preserved ejection fraction: the supplemantary role of tissue doppler imaging parameters and NT-proBNP levels

BACKGROUND

Early diagnosis of cardiovascular disease in diabetic patients may be important to introduce treatment early. Echocardiography is a method used to show the ventricular functions. A ventricular hormone, BNP is used to identify the changes in the ventricular function in early period. NT-proBNP which is a more stable compound with a longer half-life is used in measurement of BNP.

METHODS

Left ventricular diastolic dysfunction (LVDD) was detected and NT-proBNP levels were measured in forty-four asymptomatic patients with ages of 30-70 and type 2 DM and control group consisted of 40 healthy individuals from the same age group.

RESULTS

NT-proBNP levels were found as 566.7 ± 738.5 pg/ml in the diabetics with LVDD detected, 166.3 ± 137.1 pg/ml in the diabetics without LVDD and 134.5 ± 77.2 pg/ml in the control group. Levels of NT-proBNP were significantly higher in the group with left ventricular diastolic dysfunction (p<0.05). However, when the levels of NT-proBNP in the diabetic patients without LVDD were compared with the controls, the difference was not significant (p>0.05). NT-proBNP levels were found significantly higher in LVDD group compared to the controls without a difference between the ejection fractions (p<0.05).

CONCLUSION

High levels of NT-proBNP was correlated tissue Doppler echocardiography findings in type 2 DM patients with preserved ejection fraction.

Assessment of diffuse myocardial fibrosis in rats using small-animal Look-Locker inversion recovery T1 mapping

BACKGROUND

The concentration of gadopentetate dimeglumine in myocardium and blood can be assessed from T1 measurements and can be used to calculate the extracellular volume (ECV) of the myocardium. We hypothesized that diffuse myocardial fibrosis in a small-animal model could be quantitatively assessed by measuring myocardial ECV using small-animal Look-Locker inversion recovery T1 mapping.

METHODS AND RESULTS

Sprague-Dawley rats (n=10) were subjected to continuous angiotensin-2 (AT2) infusion for 2 weeks via a subcutaneously implanted minipump system. Magnetic resonance imaging (MRI) was performed both before and after AT2 infusion. The MRI protocol included multislice cine imaging and before-and-after contrast small-animal Look-Locker inversion recovery T1 mapping and late gadolinium enhancement imaging. Myocardial ECV was calculated from hematocrit and T1 values of blood and myocardium. During the course of AT2 infusion, the mean±SD systolic blood pressure increased from 122±10.9 to 152±27.5 mm Hg (P=0.003). Normalized heart weight was significantly higher in AT2-treated animals than in control littermates (P=0.033). Cine MRI documented concentric left ventricular hypertrophy. Postcontrast myocardial T1 times were shortened after treatment (median [interquartile range], 712 [63] versus 820 [131] ms; P=0.002). Myocardial ECV increased from 17.2% (4.3%) before to 23.0% (6.2%) after AT2 treatment (P=0.031), which was accompanied by perivascular fibrosis and microscarring on myocardial histological analysis. There was a moderate level of correlation between ECV and collagen volume fraction, as assessed by histological analysis (r=0.69, P=0.013).

CONCLUSIONS

In a small-animal model of left ventricular hypertrophy, contrast-enhanced T1 mapping can be used to detect diffuse myocardial fibrosis by quantification of myocardial ECV.

Predictive value of predischarge spectral tissue doppler echocardiography and n-terminal pro-B-type natriuretic peptide in patients hospitalized with acute heart failure

BACKGROUND

Admission for an acute heart failure (HF) confers an extremely poor prognosis. We aimed at finding out whether simultaneous assessment of multiple plasma-based biomarkers and Doppler echocardiography could provide complementary information and thus enable clinicians to stratify risk more effectively among patients hospitalized with acute HF; hence, untoward events after discharge avoided.

METHODS

A comprehensive echocardiographic study and measurements of cardiac troponin I (cTnI), N-terminal pro-B-type natriuretic protein (NT-proBNP), and high-sensitivity C-reactive protein (hsCRP) were conducted in 87 patients with symptomatic de novo acute HF or decompensation of chronic HF. Major adverse cardiac events (MACE) regarding cardiac death or hospitalization with worsening HF during a median follow-up period of 191 days were determined.

RESULTS

According to the univariate analysis, echocardiographic variables left atrial volume, left atrial volume index, pulmonary artery systolic pressure, E/E' ratio, and the concentrations of NT-proBNP were significantly related to clinical outcomes (all P-values < 0.05). Cox proportional hazard analysis identified two independent prognostic predictors of MACE: E/E' ratio and NT-proBNP. Moreover, the combining of plasma level of NT-proBNP with E/E' ratio provided independent and additional prognostic value in identifying high-risk acute HF patients.

CONCLUSIONS

These findings reinforce the necessity of combining the heart hemodynamic variable E/E' ratio and plasma-based neurohormonal biomarker NT-proBNP when clinicians attempt to define the individual risk of patients hospitalized with acute HF.