Is myocardial fibrosis appropriately assessed by calibrated and 2D strain derived integrated backscatter?

AIMS

Increased collagen content of the myocardium modifies tissue reflectivity and integrated backscatter (IBS) indexes are suggested as markers of myocardial fibrosis (MF). We sought to assess the correlation between calibrated (c) IBS and bidimensional (2D) strain derived IBS with left ventricular (LV) MF in patients with severe aortic stenosis (AS).

METHODS AND RESULTS

We made a prospective observational cohort study including 157 patients with severe AS referred for surgical aortic valve replacement (AVR), with complete preoperative transthoracic echocardiography, cardiac magnetic resonance (CMR) and endomyocardial biopsy (EMB) obtained from the anterior basal septum at the time of surgery. Two groups of 30 patients were specifically evaluated, with and without late gadolinium enhancement (LGE) at CMR. IBS was obtained at QRS peak from both parasternal long axis (PLAX) and apical-three-chamber (AP3C) views and measured in decibels (dB). Whole-cardiac cycle IBS at basal anterior septum was obtained from 2D longitudinal strain. Correlation analysis of reflectivity indexes was performed with global and segmental (anterior basal septum) values of native T1 and extracellular volume (ECV), and EMB collagen volume fraction (CVF) (Masson´s Trichrome). IBS values were compared in both group of patients (LGE + vs. LGE -). 60 patients (74 [36-74] years, 45% male) with high gradient (mean gradient: 63 ± 20mmHg), normal flow (45 ± 10mL/m2) AS and preserved left ventricular ejection fraction (60 ± 9%) were included. Basal septum cIBS was - 17.45 (-31.2-10.95) and - 9.17 ± 9.45dB from PLAX and A3C views, respectively. No significant correlations were found between IBS and both non-invasive CMR tissue characterization and CVF: median MF of 9.7(2.1-79.9)%. Acoustic indexes were not significantly different according to the presence of pre-operative LGE.

CONCLUSION

In this group of patients with classical severe AS, IBS reflectivity indexes are of no added value to discriminate the presence of MF.

Cardiac microstructural alterations measured by echocardiography identify sex-specific risk for heart failure

OBJECTIVE

Established preclinical imaging assessments of heart failure (HF) risk are based on macrostructural cardiac remodelling. Given that microstructural alterations may also influence HF risk, particularly in women, we examined associations between microstructural alterations and incident HF.

METHODS

We studied N=2511 adult participants (mean age 65.7±8.8 years, 56% women) of the Framingham Offspring Study who were free of cardiovascular disease at baseline. We employed texture analysis of echocardiography to quantify microstructural alteration, based on the high spectrum signal intensity coefficient (HS-SIC). We examined its relations to incident HF in sex-pooled and sex-specific Cox models accounting for traditional HF risk factors and macrostructural alterations.

RESULTS

We observed 94 new HF events over 7.4±1.7 years. Individuals with higher HS-SIC had increased risk for incident HF (HR 1.67 per 1-SD in HS-SIC, 95% CI 1.31 to 2.13; p<0.0001). Adjusting for age and antihypertensive medication use, this association was significant in women (p=0.02) but not men (p=0.78). Adjusting for traditional risk factors (including body mass index, total/high-density lipoprotein cholesterol, blood pressure traits, diabetes and smoking) attenuated the association in women (HR 1.30, p=0.07), with mediation of HF risk by the HS-SIC seen for a majority of these risk factors. However, the HS-SIC association with HF in women remained significant after adjusting for relative wall thickness (representing macrostructure alteration) in addition to these risk factors (HR 1.47, p=0.02).

CONCLUSIONS

Cardiac microstructural alterations are associated with elevated risk for HF, particularly in women. Microstructural alteration may identify sex-specific pathways by which individuals progress from risk factors to clinical HF.

Evaluation of patients with high burden of premature ventricular contractions by comprehensive transthoracic echocardiography

Background

The prevalence and prognosis of premature ventricular contractions (PVCs) among individuals without structural heart disease are uncertain. Standard transthoracic echocardiography is a common method in evaluation of underlying cardiovascular disease and is recommended as a diagnostic method in PVC patients. However, it is unclear whether comprehensive echocardiographic examination can identify pathological findings in PVC patients with a normal standard echocardiogram.

Method

We included forty consecutive patients with a high PVC burden (>10,000 PVCs/day) and normal findings at a standard echocardiogram and exercise test. All subjects were investigated by a comprehensive echocardiographic examination using parameters usually not included in a routine work-up. We compared the results with 22 age and sex-matched controls.

Results

In six additional parameters-global longitudinal strain, right ventricular strain, septal-lateral delay, ventricular-arterial coupling, integrated backscatter and left atrial activation time-a statistically significant difference was shown between PVC patients and controls. Among these parameters, global longitudinal strain had a high reliability between operators.

Conclusions

Despite normal findings at standard echocardiography, the PVC group showed signs of impaired heart function when more comprehensive echocardiography parameters were used.

Metformin in non-diabetic patients with metabolic syndrome and diastolic dysfunction: the MET-DIME randomized trial

PURPOSE

Metabolic syndrome (MetS) affects one out of 3 adults in the western world and is associated with preclinical diastolic dysfunction that impairs functional capacity and quality of life (QoL). This randomized trial was designed to evaluate if the addition of metformin to the standard treatment of non-diabetic patients with MetS improves diastolic dysfunction.

METHODS

Prospective, randomized, open-label, blinded-endpoint trial. Fifty-four non-diabetic adults with MetS and diastolic dysfunction were randomized to lifestyle counseling or lifestyle counseling plus metformin (target dose 1000 mg bid). The primary endpoint was the change in mean e' velocity (assessed at baseline, 6, 12 and 24 months). Secondary endpoints were improvements in insulin resistance, functional capacity and QoL. Linear mixed effects modeling was used for longitudinal data analysis using modified intention-to-treat (mITT) and per-protocol (PP) approaches.

RESULTS

Forty-nine patients were included in the mITT analysis (mean age = 51.8 ± 6.4; 55% males). Metformin treatment was associated with a significant decrease in HOMA-IR. There was a significantly different mean change in e' velocity during the study period between trial arms, both in the mITT (at 24 months, change of +0.67 ± 1.90 cm/s in metformin arm vs. -0.33 ± 1.50 cm/s in control arm) and PP populations (+0.80 ± 1.99 cm/s in metformin arm vs. -0.37 ± 1.52 cm/s in control arm), using a random intercept linear mixed model. There were no significant differences in peak oxygen uptake and SF-36 scores between trial arms.

CONCLUSIONS

Treatment with metformin of non-diabetic MetS patients with diastolic dysfunction, on top of lifestyle counseling, is associated with improved diastolic function.

The association of the metabolic syndrome with target organ damage: focus on the heart, brain, and central arteries

INTRODUCTION

The metabolic syndrome (MetS) is an adverse metabolic state composed of obesity, hyperglycemia/pre-diabetes, hypertension, and dyslipidemia. It substantially increases the risk of type 2 diabetes, cardiovascular disease (CVD) and mortality, and has a huge impact on public health.

AREA COVERED

The present review gives an update on the definition and prevalence of MetS, and its impact on cardiac structure and function as well as on the brain and central arteries. The association with CVD and mortality risk is discussed. Focus is mainly directed toward the subclinical target organ damage related to MetS. Data is also critically reviewed to provide evidence on the incremental prognostic value of overall MetS over its individual components.

EXPERT COMMENTARY

MetS is a clinical risk condition associated with subclinical and clinical CVD and mortality. Roughly, 30% of the world population suffer from MetS. As all components of the MetS are modifiable, optimal preventive and therapeutic measures should be initiated to improve CV risk control, particularly aggressively treating hypertension and hyperglycemia, and encouraging people to adopt healthy lifestyle as early as possible is of great importance.

The prevalence of fragmented QRS and its relationship with left ventricular systolic function in chronic kidney disease

Objective

To investigate the prevalence of fragmented QRS (fQRS) on electrocardiograms (ECG) in patients with different stages of chronic kidney disease (CKD) and to examine the association between fQRS and left ventricular systolic function.

Methods

This retrospective study analysed clinical and laboratory data from consecutive patients with CKD. The relationship between fQRS and left ventricular systolic function was evaluated using univariate and multivariate logistic regression analyses.

Results

A total of 310 patients (186 males; mean ± SD age, 52.24 ± 15.72 years) with CKD participated in this study. The prevalence of fQRS was 30.32% (94 of 310 patients). The prevalence of fQRS was more common in the inferior leads (53.19%; 50 of 94) compared with the anterior leads (21.28%; 20 of 94) and the lateral leads (25.53%; 24 of 94). Multivariate logistic regression analysis showed that left ventricular ejection fraction (odds ratio [OR] 1.356; 95% confidence interval [CI] 1.022, 2.036) and coronary artery disease (OR 2.355; 95% CI 1.056, 5.251) were independent risk factors of fQRS in patients with CKD.

Conclusion

The fQRS was prevalent in patients with CKD regardless of the CKD stage.

Mechanisms of cardiac collagen deposition in experimental models and human disease

The inappropriate deposition of extracellular matrix within the heart (termed cardiac fibrosis) is associated with nearly all types of heart disease, including ischemic, hypertensive, diabetic, and valvular. This alteration in the composition of the myocardium can physically limit cardiomyocyte contractility and relaxation, impede electrical conductivity, and hamper regional nutrient diffusion. Fibrosis can be grossly divided into 2 types, namely reparative (where collagen deposition replaces damaged myocardium) and reactive (where typically diffuse collagen deposition occurs without myocardial damage). Despite the widespread association of fibrosis with heart disease and general understanding of its negative impact on heart physiology, it is still not clear when collagen deposition becomes pathologic and translates into disease symptoms. In this review, we have summarized the current knowledge of cardiac fibrosis in human patients and experimental animal models, discussing the mechanisms that have been deduced from the latter in relation to the former. Because assessment of the extent of fibrosis is paramount both as a research tool to further understanding and as a clinical tool to assess patients, we have also summarized the current state of noninvasive/minimally invasive detection systems for cardiac fibrosis. Albeit not exhaustive, our aim is to provide an overview of the current understanding of cardiac fibrosis, both clinically and experimentally.

Metabolic Syndrome Is Associated With Impaired Diastolic Function Independently of MRI-Derived Myocardial Extracellular Volume: The MESA Study

The relationship of metabolic syndrome (MetS) and insulin resistance (one of its key pathophysiological mediators) with diastolic dysfunction and myocardial fibrosis is not well understood. This study aimed to evaluate the association of MetS with diastolic function and myocardial extracellular matrix (ECM) using cardiac MRI (CMRI) in a large community-based population. This cross-sectional analysis included 1,582 participants from the Multi-Ethnic Study of Atherosclerosis (MESA) with left ventricular ejection fraction ≥50% and no history of cardiac events. Diastolic function was assessed using tagged CMRI parameters including end-diastolic strain rate (EDSR) and strain relaxation index (SRI). ECM was evaluated using extracellular volume (ECV) quantification. Participants' mean age was 67.4 ± 8.6 years, and 48.1% were males. MetS was present in 533 individuals (33.7%), and type 2 diabetes in 250 (15.8%). In the multivariable analyses, MetS (irrespective of the presence of type 2 diabetes) and higher insulin resistance were associated with impaired diastolic function (higher SRI and lower EDSR), independent of ECV. In conclusion, MetS, irrespective of the presence of type 2 diabetes, was independently associated with impaired diastole. These functional myocardial changes seem to result from intrinsic cardiomyocyte alterations, irrespective of the myocardial interstitium (including fibrosis).

Myocardial stiffness as assessed by diastolic wall strain in adult survivors of childhood leukaemias with preserved left ventricular ejection fraction

Aims

We tested the hypothesis that myocardial stiffness as assessed by diastolic wall strain (DWS) is altered in adult survivors of childhood leukaemias with preserved left ventricular (LV) ejection fraction and explored its association with myocardial fibrosis and diastolic deformation.

Methods and results

Ninety-four (53 males) adult survivors of childhood leukaemias aged 22.2 ± 5.5 years and 66 (36 males) healthy controls were studied retrospectively. Diastolic wall strain and calibrated integrated backscatter (cIB) were measured as indices of myocardial stiffness and fibrosis, respectively. Left and right ventricular (RV) diastolic and torsional mechanics were interrogated using speckle tracking echocardiography. Patients had significantly lower LV DWS, and hence stiffer LV myocardium, and greater myocardial cIB in patients than controls (all P < 0.001). Left ventricular longitudinal, radial, and circumferential early diastolic strain rates, circumferential late diastolic strain rate, and peak twisting and untwisting velocities, tricuspid annular early diastolic velocity, and RV-free wall longitudinal early diastolic strain rate were significantly lower in patients than controls (all P < 0.05). Diastolic wall strain correlated inversely with myocardial cIB, and positively with LV longitudinal, radial, and circumferential early diastolic strain rates (all P < 0.05), while myocardial cIB correlated inversely with LV radial and circumferential early diastolic strain rates, circumferential late diastolic strain rate, peak twisting and untwisting velocities, and tricuspid annular e velocity (all P < 0.05).

Conclusion

In adult survivors of childhood leukaemias, despite the preservation of LV ejection fraction, increased stiffness of the LV myocardium is evident and is associated with myocardial fibrosis and impaired ventricular diastolic function.

Subclinical Myocardial Impairment in Metabolic Diseases

Type 2 diabetes mellitus (T2DM) and obesity are important contributors to nonischemic heart failure (HF) and atrial fibrillation. There is a 2- to 5-fold increase in HF associated with T2DM, and there is a 5% in HF risk in men and 7% increment in women for every unit increment in body mass index, after adjustment for traditional cardiovascular risk factors. Likewise, the risk of atrial fibrillation increases by about 6% per unit increase in body mass index. Metabolic cardiomyopathy leads to a number of changes in cardiac structure and function that can be recognized by imaging in the asymptomatic phase, and these parameters can be used for monitoring the progression of disease or the response to therapy. The purpose of this review is to familiarize clinicians with the potential benefits of early detection of preclinical myocardial abnormalities, as well as the mechanisms that might inform interventions to prevent disease progression in patients with T2DM and obesity.

Long-term effect of critical illness after severe paediatric burn injury on cardiac function in adolescent survivors: an observational study

BACKGROUND

Sepsis, trauma, and burn injury acutely depress systolic and diastolic cardiac function; data on long-term cardiac sequelae of pediatric critical illness are sparse. This study evaluated long-term systolic and diastolic function, myocardial fibrosis, and exercise tolerance in survivors of severe pediatric burn injury.

METHODS

Subjects at least 5 years after severe burn (post-burn:PB) and age-matched healthy controls (HC) underwent echocardiography to quantify systolic function (ejection fraction[EF%]), diastolic function (E/e'), and myocardial fibrosis (calibrated integrated backscatter) of the left ventricle. Exercise tolerance was quantified by oxygen consumption (VO2) and heart rate at rest and peak exercise. Demographic information, clinical data, and biomarker expression were used to predict long-term cardiac dysfunction and fibrosis.

FINDINGS

Sixty-five subjects (PB:40;HC:25) were evaluated. At study date, PB subjects were 19±5 years, were at 12±4 years postburn, and had burns over 59±19% of total body surface area, sustained at 8±5 years of age. The PB group had lower EF% (PB:52±9%;HC:61±6%; p=0.004), E/e' (PB:9.8±2.9;HC: 5.4±0.9;p<0.0001), VO2peak (PB:37.9±12;HC: 46±8.32 ml/min/kg; p=0.029), and peak heart rate (PB:161±26;HC:182±13bpm;p=0.007). The PB group had moderate (28%) or severe (15%) systolic dysfunction, moderate (50%) or severe diastolic dysfunction (21%), and myocardial fibrosis (18%). Biomarkers and clinical parameters predicted myocardial fibrosis, systolic dysfunction, and diastolic dysfunction.

INTERPRETATION

Severe pediatric burn injury may have lasting impact on cardiac function into young adulthood and is associated with myocardial fibrosis and reduced exercise tolerance. Given the strong predictive value of systolic and diastolic dysfunction, these patients might be at increased risk for early heart failure, associated morbidity, and mortality.

FUNDING

Conflicts of Interest and Sources of Funding: The authors do not have any conflicts of interest to declare. This work was supported by NIH (P50 GM060338, R01 GM056687, R01 HD049471, R01 GM112936, R01-GM56687 and T32 GM008256), NIDILRR (H133A120091, 90DP00430100), Shriners Hospitals for Children (84080, 79141, 79135, 71009, 80100, 71008, 87300 and 71000), FAER (MRTG CON14876), and the Department of Defense (W81XWH-14-2-0162 and W81XWH1420162). It was also made possible with the support of UTMB's Institute for Translational Sciences, supported in part by a Clinical and Translational Science Award (UL1TR000071) from the National Center for Advancing Translational Sciences (NIH).

Echocardiographic screening for non-ischaemic stage B heart failure in the community

AIMS

Incident heart failure (HF) continues to pose a common and serious problem. We sought to examine the value of echocardiographic predictors of new HF in a community-based elderly population at risk for HF, independent of and incremental to clinical evaluation.

METHODS AND RESULTS

Asymptomatic patients ≥65 years old, with ≥1 HF risk factor (hypertension, type 2 diabetes, or obesity) were recruited from the community; patients with valve disease, reduced ejection fraction (EF), and atrial fibrillation (AF) were excluded. Patients underwent standard clinical evaluation including calculation of the Charlson co-morbidity score and a comprehensive echocardiography including global longitudinal strain (GLS). Functional capacity was assessed by 6 min walk test. New HF and cardiovascular death were assessed after a mean follow-up of 14 ± 4 months by three independent cardiologists using Framingham criteria. Of 410 subjects (median age 70 years; 48% men), the prevalence of stage B HF was 13% [by LV hypertrophy (LVH)], 12% (by abnormal E/e'), 33% (by impaired GLS), and 31% [by left atrial enlargement (LAE)]. New HF symptoms developed in 49, and 2 died of cardiovascular causes, giving an event rate of 104/1000 person-years. These patients were older (P = 0.012), had a higher Charlson co-morbidity score (P < 0.001), larger LV mass and left atrium, higher E/e', and lower GLS (P < 0.05). LAE, LVH, abnormal GLS, and E/e' were independent predictors of new HF. In sequential models, LV mass and GLS added incremental information to clinical parameters. GLS significantly reclassified individuals (P = 0.002), but no reclassification improvement was identified using LV mass index, E/e', and left atrial volume index.

CONCLUSION

Echocardiographic assessment (especially GLS and LV mass) provides incremental value in predicting incident HF.

Preclinical Alterations in Myocardial Microstructure in People with Metabolic Syndrome

OBJECTIVE

Metabolic syndrome (MetS) can lead to myocardial fibrosis, diastolic dysfunction, and eventual heart failure. This study evaluated alterations in myocardial microstructure in people with MetS by using a novel algorithm to characterize ultrasonic signal intensity variation.

METHODS

Among 254 participants without existing cardiovascular disease (mean age 42 ± 11 years, 75% women), there were 162 with MetS, 47 with obesity without MetS, and 45 nonobese controls. Standard echocardiography was performed, and a novel validated computational algorithm was used to investigate myocardial microstructure based on sonographic signal intensity and distribution. The signal intensity coefficient (SIC [left ventricular microstructure]) was examined.

RESULTS

The SIC was significantly higher in people with MetS compared with people with (P < 0.001) and without obesity (P = 0.04), even after adjustment for age, sex, body mass index, hypertension, diabetes mellitus, and the ratio of triglyceride (TG) to high-density lipoprotein (HDL) cholesterol (P < 0.05 for all). Clinical correlates of SIC included TG concentrations (r = 0.21, P = 0.0007) and the TG/HDL ratio (r = 0.2, P = 0.001).

CONCLUSIONS

This study's findings suggest that preclinical MetS and dyslipidemia in particular are associated with altered myocardial signal intensity variation. Future studies are needed to determine whether the SIC may help detect subclinical diseases in people with metabolic disease, with the ultimate goal of targeting preventive efforts.

Association between metabolic syndrome and fragmented QRS complexes: Speckle tracking echocardiography study

BACKGROUND

Metabolic syndrome (MetS) is an endocrinological disease with both metabolic and physiological components. Previous studies have shown a relationship between MetS and left ventricular (LV) dysfunction. A fragmented QRS (fQRS) is a reliable electrocardiogram (ECG) finding with the importance of an indicator of myocardial fibrosis and scarring. In this study, we examined the utility of speckle tracking echocardiography (STE) in assessing LV function in MetS patients with fQRS.

METHODS

The 164 consecutive MetS patients included in the study. They were separated into two groups; those with (n=33) and those without (n=131) fQRS. The two groups were compared by obtaining LV strain values with STE.

RESULTS

Statistically significant differences between the fQRS (-) and fQRS (+) groups were identified for LV global longitudinal strain (LV-GLS) (p<0.001), maximum left atrial volume index (maxLAVI) (p≤0.001), strain rate during isovolumic relaxation period (SRivr) (p<0.001), and the E/SRivr ratio (p<0.001). In the multiple linear regression analysis, fQRS (β=-1.456, p=0.003), diabetes mellitus (β=-0.973, p=0.015), hypertension (β=-0.820, p=0.015) and MaxLAVI (β=-0.142, p=0.018) were independent predictors of LV-GLS. However, fQRS (β=21.995, p<0.001), MaxLAVI (β=3.090, p<0.001), and E/Em ratio (β=3.326, p<0.001) were also independent predictors of E/SRivr.

CONCLUSIONS

The results of this study showed that LV dysfunction was more common in MetS patients with fQRS. MetS patients, and especially those who are fQRS (+), should thus be closely monitored for subclinical LV systolic and diastolic dysfunction.

Impact of glycemic control on aortic stiffness, left ventricular mass and diastolic longitudinal function in type 2 diabetes mellitus

BACKGROUND

Poor glycemic control is associated with impaired left ventricular (LV) diastolic function in patients with type 2 diabetes mellitus (T2DM). Inappropriate LV mass increase and accelerated aortic stiffening were suggested to participate on deterioration of diastolic function. The present study investigated the inter-relationships between glycemic control, early diastolic and systolic longitudinal velocity of mitral annulus, LV mass and aortic stiffness in T2DM patients free of cardiovascular disease and with preserved LV ejection fraction, and compared them with those observed in healthy volunteers of similar age and sex distribution.

METHODS

125 T2DM patients and 101 healthy volunteers underwent noninvasive measurement of systolic (s') and early diastolic (e') velocities of mitral annulus, LV mass, carotid-femoral pulse wave velocity (cfPWV) and local carotid blood pressure (BP).

RESULTS

Forty-four (35.2%) T2DM patients had e' velocity lower than that expected for age (against 7.9% in healthy volunteers; P < 0.0001), 34 (27.2%) had cfPWV higher than that expected for age and mean BP (against 5.9% in healthy volunteers; P < 0.0001), and 71 (56.8%) had LV mass higher than that expected for body size and stroke work (against 17.6% in healthy volunteers; P < 0.0001). Carotid systolic BP was higher in T2DM patients (124 ± 14 vs 111 ± 11 mmHg; P < 0.0001). In multivariate analysis, e' velocity was independently related to age, carotid BP and s' velocity in healthy volunteers, and to male sex, age, carotid BP, heart rate and LV mass in T2DM. Glycosylated hemoglobin (HbA1c) was independently related to cfPWV and LV mass in T2DM patients. T2DM patients with HbA1c ≥6.5% (N = 85) had higher cfPWV (P < 0.05), central BP (P = 0.01), prevalence of LV hypertrophy (P = 0.01) and lower e' and s' velocity (P = 0.001 and <0.05, respectively) as compared to those with HbA1c <6.5%.

CONCLUSIONS

One-third of T2DM patients with preserved LV ejection fraction has sign of subclinical LV diastolic dysfunction. HbA1c levels are positively associated with LV mass and aortic stiffness, both of which show a negative independent impact on early diastolic velocity e', the latter through an increase in afterload. T2DM patients with suboptimal glycemic control (HbA1c ≥ 6.5%) have lower diastolic and systolic LV longitudinal performance, together with increased aortic stiffness and a higher prevalence of LV hypertrophy.

Left Ventricular Stiffness in Adolescents and Young Adults with Repaired Tetralogy of Fallot

Left ventricular (LV) remodeling after tetralogy of Fallot (TOF) repair may influence LV stiffness. We hypothesized that LV stiffness is altered after TOF repair and related to myocardial calibrated integrated backscatter (cIB) and LV diastolic myocardial deformation. Seventy-seven TOF patients and 80 controls were studied. LV stiffness was assessed by diastolic wall strain (DWS) as defined by (LVPW_systole-LVPW_diastole)/LVPW_systole, where LVPW is LV posterior wall thickness, and stiffness index as defined by (E/e/LV end-diastolic dimension), where E and e are respectively early diastolic transmitral inflow and mitral annular velocities. Septal and LVPW cIB and LV diastolic strain rates were determined. Patients had significantly lower DWS (p < 0.001), higher stiffness index (p < 0.001), and greater cIB (p < 0.001). LV DWS correlated negatively with LV stiffness index (r = -0.31, p < 0.001), septal cIB (r = -0.21, p = 0.01), E/e ratio (r = -0.30, p < 0.001) and RV end-diastolic area (r = -0.31, p < 0.001), and positively with LV early (r = 0.33, p < 0.001) and late (r = 0.20, p = 0.01) diastolic strain rates and RV fractional area change (FAC) (r = 0.24, p = 0.003). Multivariate analysis revealed E/e (β = -0.26, p = 0.008), RV end-diastolic area (β = -0.20, p = 0.02), and RV FAC (β = 0.18, p = 0.01) as significant correlates of DWS. Left ventricular stiffening occurs after TOF repair and is related to impaired LV diastolic myocardial deformation, myocardial cIB, and RV volume overload.

A non-contrast CMR index for assessing myocardial fibrosis

PURPOSE

Safe, sensitive, and non-invasive imaging methods to assess the presence, extent, and turnover of myocardial fibrosis are needed for early stratification of risk in patients who might develop heart failure after myocardial infarction. We describe a non-contrast cardiac magnetic resonance (CMR) approach for sensitive detection of myocardial fibrosis using a canine model of myocardial infarction and reperfusion.

METHODS

Seven dogs had coronary thrombotic occlusion of the left anterior descending coronary arteries followed by fibrinolytic reperfusion. CMR studies were performed at 7days after reperfusion. A CMR spin-locking T₁ρ mapping sequence was used to acquire T₁ρ dispersion data with spin-lock frequencies of 0 and 511Hz. A fibrosis index map was derived on a pixel-by-pixel basis. CMR native T₁ mapping, first-pass myocardial perfusion imaging, and post-contrast late gadolinium enhancement imaging were also performed for assessing myocardial ischemia and fibrosis. Hearts were dissected after CMR for histopathological staining and two myocardial tissue segments from the septal regions of adjacent left ventricular slices were qualitatively assessed to grade the extent of myocardial fibrosis.

RESULTS

Histopathology of 14 myocardial tissue segments from septal regions was graded as grade 1 (fibrosis area, <20% of a low power field, n=9), grade 2 (fibrosis area, 20-50% of field, n=4), or grade 3 (fibrosis area, >50% of field, n=1). A dramatic difference in fibrosis index (183%, P<0.001) was observed by CMR from grade 1 to 2, whereas differences were much smaller for T₁ρ (9%, P=0.14), native T₁ (5.5%, P=0.12), and perfusion (-21%, P=0.05).

CONCLUSION

A non-contrast CMR index based on T₁ρ dispersion contrast was shown in preliminary studies to detect and correlate with the extent of myocardial fibrosis identified histopathologically. A non-contrast approach may have important implications for managing cardiac patients with heart failure, particularly in the presence of impaired renal function.

The Association between Diffuse Myocardial Fibrosis on Cardiac Magnetic Resonance T1 Mapping and Myocardial Dysfunction in Diabetic Rabbits

The objective of this study was to assess the relationship between imaging surrogates for diffuse fibrosis and myocardial dysfunction. Thirty-six New Zealand white rabbits were classified into two groups: a control group (n = 18) and an alloxan-induced diabetes mellitus (DM) group (n = 18). For all rabbits, conventional ultrasonography, two-dimensional speckle tracking, and cardiac magnetic resonance (CMR) T1 mapping were performed; all of the rabbits were then sacrificed for Masson’s staining. The extracellular volume (ECV) was calculated from pre- and post-contrast T1 values and compared with myocardial function measured by echocardiography using Pearson’s correlation. In the DM group, ECV increased as the duration of diabetes increased, consistent with the changes in myocardial fibrosis verified by pathology. Moreover, ECV was strongly correlated with the early diastolic strain rate (r = −0.782, p < 0.001) and moderately correlated with the radial systolic peak strain (r = 0.478, p = 0.045). Thus, ECV is an effective surrogate for myocardial diffuse fibrosis on CMR imaging, and higher ECV values are associated with an increased impairment of myocardial diastolic function.

Quantitative evaluation of myocardial fibrosis by cardiac integrated backscatter analysis in Kawasaki disease

Background

Kawasaki disease is an acute, systemic vasculitis that affects the coronary arteries. However, the relationship between myocardial fibrosis and Kawasaki disease has been completely unknown until now. We aimed to provide quantitative information about myocardial fibrosis using cardiac integrated backscatter in Han race Kawasaki disease patients.

Methods

Ninety Kawasaki disease patients and 90 healthy control subjects were recruited. Based on Kawasaki disease status, the patients were categorized into 3 groups: acute, subacute, and convalescence phase. Based on coronary artery status, the Kawasaki disease patients were categorized into 3 groups: without coronary artery lesions, with coronary artery dilation, and with coronary artery aneurysms. All subjects underwent two-dimensional and Doppler examinations to measure clinical echocardiographic parameters. Myocardial fibrosis was detected with calibrated integrated backscatter imaging.

Results

Left ventricle systolic functions were normal in both the Kawasaki disease and control participants. The myocardial calibrated integrated backscatter values of the left ventricles of the acute (p < 0.001), subacute (p < 0.001) and convalescence phase (p < 0.001) Kawasaki disease patients were significantly greater than those of the healthy controls. The left ventricle myocardial calibrated integrated backscatter values were significantly smaller in the Kawasaki disease patients without coronary artery lesions than in the Kawasaki disease patients with coronary artery dilations and coronary artery aneurysms in different phases. The left ventricle myocardial calibrated integrated backscatter results were positively correlated with coronary artery status in the acute (r = 0.331, p < 0.001), subacute (r = 0.456, p < 0.001) and convalescence phases (r = 0.407, p < 0.001) of Kawasaki disease.

Conclusion

Our findings may suggest that myocardial fibrosis occurs during early episodes of Kawasaki disease given uncertainties that exist regarding correlations of calibrated integrated backscatter and myocardial fibrosis.

Myocardial Integrated Backscatter in Obese Adolescents: Associations with Measures of Adiposity and Left Ventricular Deformation

Background

Myocardial fibrosis has been proposed to play an important pathogenetic role in left ventricular (LV) dysfunction in obesity. This study tested the hypothesis that calibrated integrated backscatter (cIB) as a marker of myocardial fibrosis is altered in obese adolescents and explored its associations with adiposity, LV myocardial deformation, and metabolic parameters.

Methods/Principal Findings

Fifty-two obese adolescents and 38 non-obese controls were studied with conventional and speckle tracking echocardiography. The average cIB of ventricular septum and LV posterior wall was measured. In obese subjects, insulin resistance as estimated by homeostasis model assessment (HOMA-IR) and glucose tolerance were determined. Compared with controls, obese subjects had significantly greater cIB of ventricular septum (-16.8±7.8 dB vs -23.2±7.8 dB, p<0.001), LV posterior wall (-20.5±5.6 dBvs -25.0±5.1 dB, p<0.001) and their average (-18.7±5.7 dB vs -24.1±5.0 dB, p<0.001). For myocardial deformation, obese subjects had significantly reduced LV longitudinal systolic strain rate (SR) (p = 0.045) and early diastolic SR (p = 0.015), and LV circumferential systolic strain (p = 0.008), but greater LV longitudinal late diastolic SR (p<0.001), and radial early (p = 0.037) and late (p = 0.002) diastolic SR than controls. For the entire cohort, myocardial cIB correlated positively with body mass index (r = 0.45, p<0.001) and waist circumference (r = 0.45, p<0.001), but negatively with LV circumferential systolic strain (r = -0.23, p = 0.03) and systolic SR (r = -0.25, p = 0.016). Among obese subjects, cIB tended to correlate with HOMA-IR (r = 0.26, p = 0.07).

Conclusion

Obese adolescents already exhibit evidence of increased myocardial fibrosis, which is associated with measures of adiposity and impaired LV circumferential myocardial deformation.

Calibrated integrated backscatter and myocardial fibrosis in patients undergoing cardiac surgery

Objective

The reported association between calibrated integrated backscatter (cIB) and myocardial fibrosis is based on study of patients with dilated or hypertrophic cardiomyopathy and extensive (mean 15–34%) fibrosis. Its association with lesser degrees of fibrosis is unknown. We examined the relationship between cIB and myocardial fibrosis in patients with coronary artery disease.

Methods

Myocardial histology was examined in left ventricular epicardial biopsies from 40 patients (29 men and 11 women) undergoing coronary artery bypass graft surgery, who had preoperative echocardiography with cIB measurement.

Results

Total fibrosis (picrosirius red staining) varied from 0.7% to 4%, and in contrast to previous reports, cIB showed weak inverse associations with total fibrosis (r=−0.32, p=0.047) and interstitial fibrosis (r=−0.34, p=0.03). However, cIB was not significantly associated with other histological parameters, including immunostaining for collagens I and III, the advanced glycation end product (AGE) N^ε-(carboxymethyl)lysine (CML) and the receptor for AGEs (RAGE). When biomarkers were examined, cIB was weakly associated with log plasma levels of amino-terminal pro-B-type natriuretic peptide (r=0.34, p=0.03), creatinine (r=0.33, p=0.04) and glomerular filtration rate (r=−0.33, p=0.04), and was more strongly associated with log plasma levels of soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) (r=0.44, p=0.01) and soluble RAGE (r=0.53, p=0.002).

Conclusions

Higher cIB was not a marker of increased myocardial fibrosis in patients with coronary artery disease, but was associated with higher plasma levels of sVEGFR-1 and soluble RAGE. The role of cIB as a non-invasive index of fibrosis in clinical studies of patients without extensive fibrosis is, therefore, questionable.

Factors associated with diastolic dysfunction in patients with resistant hypertension: resist-POL study

BACKGROUND

Diastolic dysfunction has been shown to be an independent factor of cardiovascular diseases in patients with hypertension. Very often, obstructive sleep apnea (OSA) and metabolic syndrome (MS) coexist with resistant hypertension (RHTN) and may lead to diastolic dysfunction. Thus, the purpose of this study was to investigate whether OSA and MS are associated with diastolic dysfunction in patients with RHTN independently from other factors, including age, left ventricular mass index (LVMI), and blood pressure (BP).

METHODS

Data from 155 patients (n = 92 men and 63 women) were analyzed. All patients underwent thorough examination, including biochemical evaluations, ambulatory blood pressure monitoring, polysomnography with assessment of apnea/hypopnea index (AHI), and echocardiography. LVMI and diastolic function parameters were obtained.

RESULTS

Patients were divided into 2 groups based on the presence or absence of diastolic dysfunction: group 1 (E' < 10cm/second; n=87) and group 2 (E' > 10cm/second; n = 68). AHI, LVMI, and 24-hour systolic BP/diastolic BP values were higher in group 1. E' correlated with AHI (r = -0.25; P < 0.001), LVMI (r = -0.36; P < 0.0001), 24-h systolic BP/24-h diastolic BP (r = -0.28, P < 0.001; r = -0.30, P < 0.001, respectively), glucose level (r = -0.26; P < 0.01), and abdominal obesity (r = -0.28; P < 0.0001). In multivariable models decreased E' was independently related to the presence of MS or abdominal obesity when separate components of MS were included in the model. Age and 24-hour systolic BP were independently associated with decreased E'. However, the relationship of decreased E' with 24-hour systolic BP was nonsignificant if LVMI was included in the multivariable model.

CONCLUSIONS

MS and abdominal obesity were independently associated with diastolic dysfunction in patients with RHTN. OSA was not confirmed to be an independent factor of diastolic dysfunction.

The N-terminal propeptide of type III procollagen in patients with acute coronary syndrome: a link between left ventricular end-diastolic pressure and cardiovascular events

Background

Despite the usefulness of N-terminal propeptide of type III procollagen (PIIINP) in detecting enhanced collagen turnover in patients with congestive heart failure, the value added by PIIINP to the use of clinical variables and echocardiography in relation to directly measured left ventricular (LV) end-diastolic pressure (EDP) and the outcome of acute coronary syndrome (ACS) has not been clearly defined.

Methods and Results

This study involved 168 adult patients with ACS, who underwent echocardiography, measurement of serum PIIINP levels, and cardiac catheterization. Pulsed wave tissue Doppler imaging (PWTDI), which revealed mean peak systolic (s′), early (e′), and late diastolic (a′) velocities, was carried out and the eas index of LV function was evaluated: e′/(a′×s′). The patients were divided into three study groups based on the degree of LVEDP – normal (<16 mmHg), intermediate (16–30 mmHg), and high (>30 mmHg) LVEDP. All patients were followed-up to determine cardiac-related death and revascularization. Patients with high LVEDP had significantly more PIIINP than those with intermediate or normal LVEDP (all post hoc p<0.05). The presence of coronary artery disease, the left atrial volume index (LAVI), the ratio of transmitral early and late diastolic flow velocities, a′, and the eas index were significantly correlated with LVEDP. According to multiple stepwise analysis, PIIINP, LAVI and the eas index were the three independent predictors of the level of LVEDP (PIIINP, p <0.001; LAVI, p = 0.007; eas index, p = 0.021). During follow-up (median, 24 months), 32 participants suffered from cardiac events, PIIINP and LAVI were significant predictors of cardiac mortality and hospitalization (PIIINP, hazard ratio (HR) 2.589, p = 0.002; LAVI, HR 1.040, p = 0.027).

Conclusions

PIIINP is a highly effective means to evaluate LVEDP in patients with ACS. The PIIINP is also correlated with cardiac mortality and revascularization, providing an additional means of evaluating and managing patients with ACS.

METformin in DIastolic Dysfunction of MEtabolic syndrome (MET-DIME) trial: rationale and study design : MET-DIME trial

PURPOSE

Insulin resistance plays a central role in the pathophysiology of metabolic syndrome (MS). Its cardiac deleterious effects are characterized by an increase in fibrous tissue that increases myocardial stiffness and contributes to subclinical left ventricular diastolic dysfunction (LVDD) and heart failure with preserved ejection fraction in patients with MS. In addition to lifestyle counseling (LC), metformin treatment may attenuate or even reverse diastolic dysfunction in these patients. This trial aims to evaluate if treating non-diabetic patients with MS and LVDD with metformin in addition to LC improves diastolic function and assess its impact in functional capacity and health-related quality of life (HRQoL).

DESIGN

MET-DIME is a phase II prospective, randomized, open-label, blinded-endpoint trial with a scheduled follow-up of 24 months. Fifty-four patients (adults 40-65 years old with AHA/NHLBI criteria of MS and rest LVDD) will be randomized by minimization to LC only or LC plus metformin (target dose of 1,000 mg twice daily). The primary endpoint will be change in mean of early diastolic mitral annular velocity, an echocardiographic parameter highly correlated with myocardial fibrosis (serial measurements will be performed at 6, 12 and 24 months). The secondary endpoints will include change in diastolic parameters at rest; metabolic, inflammatory and remodeling biomarkers; functional capacity; adipose tissue volumes and HRQoL.

CONCLUSION

MET-DIME is a pragmatic trial designed to evaluate if adding metformin to the standard treatment of patients with MS improves diastolic dysfunction, assessing its impact in metabolic homeostasis, proinflammatory state, functional capacity and HRQoL.

Influence of serum adiponectin level and SNP +45 polymorphism of adiponectin gene on myocardial fibrosis

Adiponectin plays an important role in the development of hypertension, atherosclerosis, and cardiomyocyte hypertrophy, but very little was known about the influence of serum adiponectin or the adiponectin gene polymorphism on myocardial fibrosis. Our study investigates the influence of the SNP +45 polymorphism of the adiponectin gene and serum levels of adiponectin on myocardial fibrosis in patients with essential hypertension. A case-control study was conducted on 165 hypertensive patients and 126 normotensive healthy controls. The genotypes of adiponectin gene polymorphisms were detected by the polymerase chain reaction (PCR) method. Serum concentrations of procollagen were measured by a double antibody sandwich enzyme-linked immunosorbent assay (ELISA) in all subjects. The integrated backscatter score (IBS) was measured in the left ventricular myocardium using echocardiography. The serum levels of adiponectin in hypertensive patients were significantly lower than those in the normal control group ((2.69±1.0) μg/ml vs. (4.21±2.89) μg/ml, respectively, P<0.001). The serum levels of type-I procollagen carboxyl end peptide (PICP) and type-III procollagen ammonia cardinal extremity peptide (PIIINP) in the hypertension group were significantly higher than those in the control group. In the hypertension group, serum levels of adiponectin were significantly and negatively related to the average acoustic intensity and corrected acoustic intensity of the myocardium (r=0.46 and 0.61, respectively, P<0.05 for both). The serum levels of PICP and PIIINP were significantly different among the three genotypes of SNP +45 (P<0.01). Logistic regression analyses showed that sex and genotype (GG+GT) were the major risk factors of myocardial fibrosis in hypertensive patients (OR=5.343 and 3.278, respectively, P<0.05). These data suggest that lower levels of adiponectin and SNP +45 polymorphism of the adiponectin gene are likely to play an important role in myocardial fibrosis in hypertensive patients.

Myocardial tissue remodeling in adolescent obesity

BACKGROUND

Childhood obesity is a significant risk factor for cardiovascular disease in adulthood. Although ventricular remodeling has been reported in obese youth, early tissue-level markers within the myocardium that precede organ-level alterations have not been described.

METHODS AND RESULTS

We studied 21 obese adolescents (mean age, 17.7±2.6 years; mean body mass index [BMI], 41.9±9.5 kg/m(2), including 11 patients with type 2 diabetes [T2D]) and 12 healthy volunteers (age, 15.1±4.5 years; BMI, 20.1±3.5 kg/m(2)) using biomarkers of cardiometabolic risk and cardiac magnetic resonance imaging (CMR) to phenotype cardiac structure, function, and interstitial matrix remodeling by standard techniques. Although left ventricular ejection fraction and left atrial volumes were similar in healthy volunteers and obese patients (and within normal body size-adjusted limits), interstitial matrix expansion by CMR extracellular volume fraction (ECV) was significantly different between healthy volunteers (median, 0.264; interquartile range [IQR], 0.253 to 0.271), obese adolescents without T2D (median, 0.328; IQR, 0.278 to 0.345), and obese adolescents with T2D (median, 0.376; IQR, 0.336 to 0.407; P=0.0001). ECV was associated with BMI for the entire population (r=0.58, P<0.001) and with high-sensitivity C-reactive protein (r=0.47, P<0.05), serum triglycerides (r=0.51, P<0.05), and hemoglobin A1c (r=0.76, P<0.0001) in the obese stratum.

CONCLUSIONS

Obese adolescents (particularly those with T2D) have subclinical alterations in myocardial tissue architecture associated with inflammation and insulin resistance. These alterations precede significant left ventricular hypertrophy or decreased cardiac function.

The year 2012 in the European Heart Journal-Cardiovascular Imaging: Part I

The new multi-modality cardiovascular imaging journal, European Heart Journal - Cardiovascular Imaging, was started in 2012. During its first year, the new Journal has published an impressive collection of cardiovascular studies utilizing all cardiovascular imaging modalities. We will summarize the most important studies from its first year in two articles. The present 'Part I' of the review will focus on studies in myocardial function, myocardial ischaemia, and emerging techniques in cardiovascular imaging.

Improvement in collagen metabolism after 12 weeks' cardiac resynchronization therapy in patients with ischaemic cardiomyopathy

OBJECTIVES

To investigate the effects of cardiac resynchronization therapy (CRT) on collagen metabolism biomarkers and their relationship to cardiac function, in patients with ischaemic cardiomyopathy (ICM).

METHODS

Serum levels of matrix metalloproteinase (MMP)-9, tissue inhibitor of MMP-9 (TIMP-1), carboxyterminal propeptide of type I procollagen (PICP) and carboxyterminal telopeptide of type I collagen (ICTP) were quantified before and after 12 weeks' treatment, in patients with ICM receiving CRT and standard medical therapy (CRT group) or standard medical therapy alone (non-CRT group), and in controls. Cardiac function was measured echocardiographically.

RESULTS

MMP-9, TIMP-1, ICTP and the MMP-9/TIMP-1 ratio were significantly higher, and the PICP/ICTP ratio significantly lower, in patients with ICM (n = 27) compared with controls (n = 20). After 12 weeks' treatment, MMP-9, TIMP-1, ICTP and the MMP-9/TIMP-1 ratio were significantly higher, and the PICP/ICTP ratio significantly lower, in the non-CRT group (n = 15) compared with the CRT group (n = 12). The PICP/ICTP ratio correlated positively with TIMP-1 and negatively with MMP-9. The early/atrial ratio and left ventricular ejection fraction correlated positively and negatively, respectively, with the MMP-9/TIMP-1 ratio. Echocardiographic measurements of cardiac function were significantly worse in patients with ICM compared with controls and improved significantly after treatment in the CRT group.

CONCLUSIONS

In ICM, collagen degradation biomarkers were elevated and correlated positively with cardiac function. CRT partially reversed the deterioration in collagen metabolism and enhanced cardiac function.