Wessel P. Brouwer

Comparison between three-dimensional speckle-tracking echocardiography and cardiac magnetic resonance imaging for quantification of left ventricular volumes and function

AIMS We evaluated the accuracy of three-dimensional speckle-tracking echocardiography (3DSTE) to evaluate left ventricular (LV) volumes, ejection fraction (EF), and global circumferential strain (CS) in comparison with cardiac magnetic resonance imaging (MRI) in a healthy population. METHODS AND RESULTS A total of 45 out of 50 consecutive healthy subjects (38 males, age 45 ± 15 years) successfully underwent both 3DSTE and MRI on the same day. Three-dimensional echocardiography data sets were analysed using speckle tracking to measure LV end-diastolic and end-systolic volumes, EF, and global CS. With MRI, the method of discs approximation was used to obtain volumes and the EF, whereas CS was acquired using myocardial tissue tagging. Inter-technique comparisons included regression and the Bland-Altman analysis. For quantification of LV volumes, 3DSTE correlated well with MRI (r: 0.75-0.81), but volumes were significantly underestimated with relatively large biases (13-34 mL) and wide limits of agreement (SD: 11-25 mL). However, excellent accuracy was revealed for measurement of EF by 3DSTE with a good correlation (r: 0.91), minimal bias, and narrow limits of agreement (0.6 ± 1.7%) compared with MRI. For measurement of CS, a large mean bias was found between techniques (10.0%), despite narrow limits of agreement (SD: 1.7%) and a good correlation between techniques (r: 0.80). CONCLUSION Although 3DSTE-derived LV volumes are underestimated in most patients compared with MRI, measurement of the LVEF revealed excellent accuracy. Measurements of CS were systematically greater (i.e. more negative) with 3DSTE than MRI, which likely reflects various inter-technique differences that preclude direct comparability of their measurements.

Increased left ventricular torsion in hypertrophic cardiomyopathy mutation carriers with normal wall thickness

BackgroundIncreased left ventricular (LV) torsion has been observed in patients with manifest familial hypertrophic cardiomyopathy (HCM), and is thought to be caused by subendocardial dysfunction. We hypothesize that increased LV torsion is already present in healthy mutation carriers with normal wall thickness.MethodsSeventeen carriers with an LV wall thickness <10 mm, and seventeen age and gender matched controls had cardiovascular magnetic resonance (CMR) cine imaging and tissue tagging. LV volumes and mass were calculated from the cine images. LV torsion, torsion rate, endocardial circumferential strain and torsion-to-endocardial-circumferential-shortening (TECS) ratio, which reflects the transmural distribution in contractile function, were determined using tissue tagging.ResultsLV volumes, mass and circumferential strain were comparable between groups, whereas LV ejection fraction, torsion and TECS-ratio were increased in carriers compared to controls (63 ± 3% vs. 60 ± 3%, p = 0.04, 10.1 ± 2.5° vs. 7.7 ± 1.2°, p = 0.001, and 0.52 ± 0.14°/% vs. 0.42 ± 0.10°/%, p = 0.02, respectively).ConclusionsCarriers with normal wall thickness display increased LV torsion and TECS-ratio with respect to controls, which might be due to subendocardial myocardial dysfunction. As similar abnormalities are observed in patients with manifest HCM, the changes in healthy carriers may be target for clinical intervention to delay or prevent the onset of hypertrophy.

T1 Mapping Shows Increased Extracellular Matrix Size in the Myocardium Due to Amyloid Depositions

Amyloidosis is a systemic infiltrative disorder in which insoluble protein fibrils are deposited in the extracellular matrix (ECM). The prognosis is predominantly determined by cardiac involvement because the amyloid depositions lead to a restrictive cardiomyopathy. Although endomyocardial biopsy is the gold standard for diagnosing cardiac amyloidosis, the associated risk for complications favors a noninvasive approach by using various cardiac imaging methods, whereas tissue diagnosis is made on a noncardiac biopsy. Accurate diagnosis of cardiac amyloidosis becomes difficult when a secondary cause of myocardial wall thickening (eg, hypertension) is present as well. Cardiac MRI is an excellent tool for assessment of systolic and diastolic function, myocardial thickness, and amyloid deposition with late gadolinium enhancement imaging.1 Late gadolinium enhancement imaging is a qualitative technique, which relies on the presence of normal myocardium to visualize infiltrated, enhanced tissue. Therefore, diffuse deposition of amyloid is difficult to highlight, because regional differences in signal intensities may be absent. T1-mapping is a cardiac MR technique, which allows absolute quantification of T1 values of the myocardium and enables assessment of ECM expansion present in cardiac amyloidosis. A 71-year-old man with a medical history of hypertension presented with suspicion of congestive heart failure. A 12-lead electrocardiography showed atrial fibrillation and low voltages in the …

Multiple myocardial crypts on modified long-axis view are a specific finding in pre-hypertrophic HCM mutation carriers

AIMS Crypts can be found with cardiovascular magnetic resonance imaging (CMR) in hypertrophic cardiomyopathy (HCM) mutation carriers without hypertrophy (carriers) using a modified two-chamber view through the inferoseptum, but also in other patients and healthy individuals with standard long-axis views. Since it is currently unknown if carriers display a specific crypt morphology, we compared crypts in carriers with other cardiac pathologies (controls). Besides, we aimed to determine the optimal imaging plane for the detection of crypts by comparing modified two-chamber views with standard long-axis views. Finally, we evaluated the accuracy of crypts to identify carriers in HCM family screening. METHODS AND RESULTS Standard CMR long-axis views with additional modified two-chamber views were prospectively performed in carriers (n= 43), consecutive CMR control patients (n= 252), and mutation-negative family members (n= 15). Crypts were found in 70% (30/43) of carriers and in 12% (31/252) of controls (P< 0.001). Crypts in carriers showed deeper penetrance into the myocardium compared with controls (74 ± 21% vs. 59 ± 22%, P< 0.01). Detection of two or more crypts had a sensitivity of 51% and specificity of 94% for carriership. Modified two-chamber views doubled the sensitivity to detect crypts compared with standard long-axis views. In family screening, ≥2 crypts had a 100% positive predictive value to identify carriers. CONCLUSIONS Multiple crypts in the absence of left ventricular hypertrophy are highly specific for HCM mutation carriership and warrant clinical follow-up. A modified two-chamber view has a superior sensitivity compared with standard long-axis views for crypt detection. CMR may be of additional value to identify carriers in family screening.

In-vivo T1 cardiovascular magnetic resonance study of diffuse myocardial fibrosis in hypertrophic cardiomyopathy

BackgroundIn hypertrophic cardiomyopathy (HCM), autopsy studies revealed both increased focal and diffuse deposition of collagen fibers. Late gadolinium enhancement imaging (LGE) detects focal fibrosis, but is unable to depict interstitial fibrosis. We hypothesized that with T1 mapping, which is employed to determine the myocardial extracellular volume fraction (ECV), can detect diffuse interstitial fibrosis in HCM patients.MethodsT1 mapping with a modified Look-Locker Inversion Recovery (MOLLI) pulse sequence was used to calculate ECV in manifest HCM (n = 16) patients and in healthy controls (n = 14). ECV was determined in areas where focal fibrosis was excluded with LGE.ResultsThe total group of HCM patients showed no significant changes in mean ECV values with respect to controls (0.26 ± 0.03 vs 0.26 ± 0.02, p = 0.83). Besides, ECV in LGE positive HCM patients was comparable with LGE negative HCM patients (0.27 ± 0.03 vs 0.25 ± 0.03, p = 0.12).ConclusionsThis study showed that HCM patients have a similar ECV (e.g. interstitial fibrosis) in myocardium without LGE as healthy controls. Therefore, the additional clinical value of T1 mapping in HCM seems limited, but future larger studies are needed to establish the clinical and prognostic potential of this new technique within HCM.

Carriers of the hypertrophic cardiomyopathy MYBPC3 mutation are characterized by reduced myocardial efficiency in the absence of hypertrophy and microvascular dysfunction

Next to left ventricular (LV) hypertrophy, hypertrophic cardiomyopathy (HCM) is characterized by microvascular dysfunction and reduced myocardial external efficiency (MEE). Insights into the presence of these abnormalities as early markers of disease are of clinical importance in risk stratification, and development of therapeutic approaches. Therefore, the aim was to investigate myocardial perfusion and energetics in genotype‐positive, phenotype‐negative HCM subjects (carriers).

The development of familial hypertrophic cardiomyopathy: from mutation to bedside

Eur J Clin Invest 2011; 41 (5): 568–578

The role of cardiac magnetic resonance imaging in differentiating the underlying causes of left ventricular hypertrophy

The onset of sudden cardiac death and large inter- and intra-familial clinical variability of hypertrophic cardiomyopathy pose an important clinical challenge. Cardiac magnetic resonance imaging is a high-resolution imaging modality that has become increasingly available in the past decade and has the unique possibility to demonstrate the presence of fibrosis or scar using late gadolinium enhancement imaging. As a result, the diagnostic and prognostic potential of cardiac magnetic resonance imaging has been extensively explored in acute and chronic ischaemic cardiomyopathy, as well as in several nonischaemic cardiomyopathies.This review aims to provide a critical overview of recently published studies on hypertrophic cardiomyopathy and discusses the role of cardiac magnetic resonance imaging in differentiating underlying causes of hypertrophic cardiomyopathy, such as familial hypertrophic cardiomyopathy, cardiac involvement in systemic disease and left ventricular hypertrophy due to endurance sports. Also, it demonstrates the use of cardiac magnetic resonance in risk stratification for the onset of sudden cardiac death, and early identification of asymptomatic family members of hypertrophic cardiomyopathy patients who are at risk for the development of hypertrophic cardiomyopathy. (Neth Heart J 2010;18:135-43.)

The effect of inhibition of the Na+/H+ exchanger on the development of hypertrophy in hypertrophic cardiomyopathy

In hypertrophic cardiomyopathy (HCM), the pathogenesis of asymmetrical left ventricular (LV) wall thickening is based upon a complex interplay of molecular pathways and is still largely unclarified. Since cariporide (an Na+/H+ exchange blocker) has been proven effective in several pressure overload (animal) models by inhibiting the hypertrophic response, we hypothesized that cariporide might prevent or diminish the development of hypertrophy seen in HCM. Therefore, we treated transgenic mice (homozygous cMyBP-C null mice) with cariporide and subjected them to cardiomagnetic resonance imaging (CMR).

THE EFFECT OF INHIBITION OF THE NA(+)/H+ EXCHANGER ON THE DEVELOPMENT OF HYPERTROPHY IN HYPERTROPHIC CARDIOMYOPATHY

Introduction In hypertrophic cardiomyopathy (HCM), the pathogenesis of asymmetrical left ventricular (LV) wall thickening is based upon a complex interplay of molecular pathways and is still largely unclarified. Since cariporide (an Na/H exchange blocker) has been proven effective in several pressure overload (animal) models by inhibiting the hypertrophic response, we hypothesized that cariporide might prevent or diminish the development of hypertrophy seen in HCM. Therefore, we treated transgenic mice (homozygous cMyBP-C null mice) with cariporide and subjected them to cardiomagnetic resonance imaging (CMR).