Left ventricular septal convexity in differentiating hypertrophic cardiomyopathy from hypertensive heart disease – cardiac MRI study

Background

Subjects with hypertrophic cardiomyopathy (HCM) and hypertensive heart disease (HHD) have left ventricular hypertrophy (LVH). It is a common clinical problem to distinguish HCM from HHD. Septal convexity (SC) into the left ventricle is increased in subjects with hypertrophic cardiomyopathy (HCM)-causing mutations with and without LVH.

Purpose

Our objective was to study if SC by cardiac magnetic resonance (CMR) differentiates between HCM and HHD.

Methods

We measured SC in 29 subjects with hypertension and LVH (left ventricular maximal wall thickness (LVMWT) ≥13 mm), in 49 subjects with HCM (LVMWT ≥13 mm) caused by the D175N mutation in the alpha-tropomyosin (TPM1) or the Q1061X mutation in the myosin binding protein C (MYBPC3) genes, and in 20 healthy controls with no LVH. SC into the LV was measured in end-diastolic 4-chamber images as the maximal distance between LV septal endocardial border and a line connecting septal mid-wall points at the level of tricuspid valve insertion and at the level of apical right ventricular insertion on the LV.

Results

Subjects with HCM had significantly increased septal convexity compared to subjects with HHD both in non-indexed and in BSA-indexed measurements (10.7±4.0 mm vs 4.9±2.7 mm, P<0.001 and 5.5±2.1 mm/m2 vs 2.4±1.3 mm/m2, P<0.001). To differentiate between HCM and HHD, septal convexity cutoff value of 7.85 mm performed best with sensitivity of 77% and specificity of 90%. BSA-indexed SC cutoff value of 3.68 mm differentiated between HCM and HHD with sensitivity of 81% and specificity of 86%.

Conclusions

CMR derived septal convexity is easily measured and is useful in discriminating between HCM caused by sarcomere mutations versus HHD.

Measurement of septal convexity

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): Finnish Foundation of Cardiovascular Research, the special governmental subsidy for health sciences research of the University Hospital of Kuopio

Rotation and torsion of the left ventricle with cardiovascular magnetic resonance tagging: comparison of two analysis methods

Background

Left ventricle rotation and torsion are fundamental components of myocardial function, and several software packages have been developed for analysis of these components. The purpose of this study was to compare the suitability of two software packages with different technical principles for analysis of rotation and torsion of the left ventricle during systole.

Methods

A group of hypertrophic cardiomyopathy (HCM) patients (N = 14, age 43 ± 11 years), mutation carriers without hypertrophy (N = 10, age 34 ± 13 years), and healthy relatives (N = 12, age 43 ± 17 years) underwent a cardiovascular magnetic resonance examination, including spatial modulation of magnetization tagging sequences in basal and apical planes of the left ventricle. The tagging images were analyzed offline using a harmonic phase image analysis method with Gabor filtering and a non-rigid registration-based free-form deformation technique. Left-ventricle rotation and torsion scores were obtained from end-diastole to end-systole with both software.

Results

Analysis was successful in all cases with both software applications. End-systolic torsion values between the study groups were not statistically different with either software. End-systolic apical rotation, end-systolic basal rotation, and end-systolic torsion were consistently higher when analyzed with non-rigid registration than with harmonic phase-based analysis (p <  0.0001). End-systolic rotation and torsion values had significant correlations between the two software (p <  0.0001), most significant in the apical plane.

Conclusions

When comparing absolute values of rotation and torsion between different individuals, software-specific reference values are required. Harmonic phase flow with Gabor filtering and non-rigid registration-based methods can both be used reliably in the analysis of systolic rotation and torsion patterns of the left ventricle.

Severe pulmonary regurgitation in adolescents with tetralogy of Fallot leads to increased longitudinal strain

Objectives

Postoperative patients with tetralogy of Fallot (TOF) are often compromised by chronic pulmonary regurgitation and chronic right ventricular volume load. We sought to determine whether pulmonary regurgitation (PR) would affect right and left ventricle (RV and LV) strain.

Materials and methods

This cross-sectional analysis included 40 patients who had TOF with surgical repair, with an average follow-up period of 11.8 ± 3.0 years. Altogether, 44 healthy volunteers with similar age and gender distribution were recruited. A cardiovascular magnetic resonance imaging study with feature tracking analysis was performed on all patients and controls.

Results

RV peak longitudinal strain was increased in TOF patients with PR > 30 ml/m² when compared to those with PR < 30 ml/m² (− 22.5% ± 2.7% vs − 19.7% ± 3.5%, p = 0.018) and controls (p = 0.007). PR volume correlated with peak RV longitudinal strain (R = − 0.37, p = 0.030) and peak RV longitudinal strain rate (systolic: R = 0.37, p = 0.03; diastolic: R = 0.39, p = 0.021). The peak RV circumferential strain, from base to apex, increased more than in healthy controls (apex-base difference 7.6% ± 4.2% vs 3.3% ± 2.4%, p < 0.0001).

Conclusions

Pediatric patients with TOF and a severe pulmonary regurgitation show an enhanced longitudinal strain when compared to patients with milder regurgitation or to control subjects. In addition, mean RV circumferential strain of the patients is significantly enhanced compared to healthy individuals.

CMR derived left ventricular septal convexity in carriers of the hypertrophic cardiomyopathy-causing MYBPC3-Q1061X mutation

This manuscript has not been published before and is not currently being considered for publication elsewhere. Increased septal convexity of left ventricle has been described in subjects with hypertrophic cardiomyopathy (HCM) -causing mutations without left ventricular hypertrophy (LVH). Our objective was to study septal convexity by cardiac magnetic resonance (CMR) in subjects with the Finnish founder mutation Q1016X in the myosin-binding protein C gene (MYBPC3). Septal convexity was measured in end-diastolic 4-chamber CMR image in 67 study subjects (47 subjects with the MYBPC3-Q1061X mutation and 20 healthy relatives without the mutation). Septal convexity was significantly increased in subjects with the MYBPC3-Q1061X mutation and LVH (n = 32) compared to controls (11.4 ± 4.3 vs 2.7 ± 3.2 mm, P < 0.001). In mutation carriers without LVH, there was a trend for increased septal convexity compared to controls (4.9 ± 2.5 vs 2.7 ± 3.2 mm, P = 0.074). When indexed for BSA, septal convexity in mutation carriers without LVH was 2.8 ± 1.4 mm/m² and 1.5 ± 1.6 mm/m² in controls (P = 0.036). In all mutation carriers, septal convexity correlated significantly with body surface area, age, maximal LV wall thickness, LV mass, and late gadolinium enhancement. Subjects with the MYBPC3–Q10961X mutation have increased septal convexity irrespective of the presence of LVH. Septal convexity appears to reflect septal remodeling, and could be useful in recognizing LVH negative mutation carriers.

Novel electrocardiographic features in carriers of hypertrophic cardiomyopathy causing sarcomeric mutations

OBJECTIVES

The sensitivity and specificity of the conventional 12-lead ECG to identify carriers of hypertrophic cardiomyopathy (HCM) - causing mutations without left ventricular hypertrophy (LVH) has been limited. We assessed the ability of novel electrocardiographic parameters to improve the detection of HCM mutation carriers.

METHODS

We studied 140 carriers (G+) of the TPM1-Asp175Asn or MYBPC3-Gln1061X pathogenic variants for HCM: The G+/LVH+ group (n = 98) consisted of mutation carriers with LVH and the G+/LVH- group (n = 42) without LVH. The control group consisted of 30 subjects. The standard 12-lead ECG was comprehensively analyzed and two novel ECG variables were introduced: RV1<RV2>RV3 and septal remodeling. A subset of 65 individuals underwent cardiac magnetic resonance imaging and 2D strain echocardiography.

RESULTS

Conventional major ECG criteria were sensitive (90%) and specific (97%) in identifying G+/LVH+ subjects. RV1<RV2>RV3 and septal remodeling were more prevalent in the G+/LVH- subjects compared to the control group (33% vs 3%, p = 0.005 and 45% vs 3%, p < 0.001, respectively). The combination of RV1<RV2>RV3 and Q waves and repolarization abnormalities (QR) differentiated between the G+/LVH- subjects and the control group with a sensitivity of 52% and specificity of 97%. The combination of septal remodeling and QR differentiated between G+/LVH- subjects and the control group with a sensitivity of 64% and specificity of 97%.

CONCLUSIONS

The novel ECG-parameters RV1<RV2>RV3 and septal remodeling were effective in identifying G+/LVH- subjects and could be useful in the diagnostics of new suspected HCM patients and in the screening and follow-up of HCM families.

Characterization of different fat depots in NAFLD using inflammation-associated proteome, lipidome and metabolome

Non-alcoholic fatty liver disease (NAFLD) is recognized as a liver manifestation of metabolic syndrome, accompanied with excessive fat accumulation in the liver and other vital organs. Ectopic fat accumulation was previously associated with negative effects at the systemic and local level in the human body. Thus, we aimed to identify and assess the predictive capability of novel potential metabolic biomarkers for ectopic fat depots in non-diabetic men with NAFLD, using the inflammation-associated proteome, lipidome and metabolome. Myocardial and hepatic triglycerides were measured with magnetic spectroscopy while function of left ventricle, pericardial and epicardial fat, subcutaneous and visceral adipose tissue were measured with magnetic resonance imaging. Measured ectopic fat depots were profiled and predicted using a Random Forest algorithm, and by estimating the Area Under the Receiver Operating Characteristic curves. We have identified distinct metabolic signatures of fat depots in the liver (TAG50:1, glutamate, diSM18:0 and CE20:3), pericardium (N-palmitoyl-sphinganine, HGF, diSM18:0, glutamate, and TNFSF14), epicardium (sphingomyelin, CE20:3, PC38:3 and TNFSF14), and myocardium (CE20:3, LAPTGF-β1, glutamate and glucose). Our analyses highlighted non-invasive biomarkers that accurately predict ectopic fat depots, and reflect their distinct metabolic signatures in subjects with NAFLD.

Fibrosis and wall thickness affect ventricular repolarization dynamics in hypertrophic cardiomyopathy

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is characterized by ventricular repolarization abnormalities and risk of ventricular arrhythmias. Our aim was to study the association between the phenotype and ventricular repolarization dynamics in HCM patients.

METHODS

HCM patients with either the MYBPC3-Q1061X or TPM1-D175N mutation (n = 46) and control subjects without mutation and hypertrophy (n = 35) were studied with 24-hr ambulatory ECG recordings by measuring time intervals of rate-adapted QT (QTe), maximal QT, and T-wave apex to wave end (TPE) intervals and the QTe/RR slope. Findings were correlated to specified echocardiographic and cardiac magnetic resonance imaging (CMRI) findings.

RESULTS

Rate-adapted QTe interval was progressively longer in HCM patients with decreasing heart rates compared to control subjects (p = 0.020). The degree of hypertrophy correlated with measured QTe values. HCM patients with maximal wall thickness higher than the mean (20.6 mm) had longer maximum QTe and median TPE intervals compared to control subjects and HCM patients with milder hypertrophy (p < 0.001 and p = 0.014, respectively). HCM patients with late gadolinium enhancement (LGE) on CMRI had steeper QTe/RR slopes compared to HCM patients without LGE and control subjects (p = 0.044 and p = 0.001, respectively). LGE was an independent predictor of QTe/RR slope (p = 0.023, B = 0.043).

CONCLUSION

Dynamics of ventricular repolarization in HCM are affected by hypertrophy and fibrosis. LGE may confer an independent effect on QT dynamics which may increase the arrhythmogenic potential in HCM.

Metabolic syndrome associates with left atrial dysfunction

BACKGROUND AND AIMS

Obesity and metabolic syndrome (MetS) are risk factors of atrial fibrillation (AF), but limited data exist on their effect on left atrial (LA) function. The aim of the study was to evaluate the effects of cardiac, hepatic and intra-abdominal ectopic fat depots and cardiometabolic risk factors on LA function in non-diabetic male subjects.

METHODS AND RESULTS

Myocardial and hepatic triglyceride contents were measured with 1.5T ¹H-magnetic resonance spectroscopy and LA and left ventricular function, visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT), epicardial and pericardial fat by magnetic resonance imaging (MRI) in 33 men with MetS and 40 men without MetS. LA volumes were assessed using a novel three-chamber orientation based MRI approach. LA ejection fraction (EF) was lower in MetS patients than in the control group (44 ± 7.7% in MetS vs. 49 ± 8.6% in controls, p = 0.013) without LA enlargement, indicating LA dysfunction. LA EF correlated negatively with waist circumference, body mass index, SAT, VAT, fasting serum insulin, and homeostasis model assessment of insulin resistance index, and positively with fasting serum high-density lipoprotein cholesterol. VAT was the best predictor of reduced LA EF.

CONCLUSIONS

MetS associates with subclinical LA dysfunction. Multiple components of MetS are related to LA dysfunction, notably visceral obesity and insulin resistance. Further studies are needed to elucidate the role of mechanical atrial remodeling in the development of AF.

Peak CK-MB has a strong association with chronic scar size and wall motion abnormalities after revascularized non-transmural myocardial infarction - a prospective CMR study

BACKGROUND

Large myocardial infarction (MI) is associated with adverse left ventricular (LV) remodeling (LVR). We studied the nature of LVR, with specific attention to non-transmural MIs, and the association of peak CK-MB with recovery and chronic phase scar size and LVR.

METHODS

Altogether 41 patients underwent prospectively repeated cardiovascular magnetic resonance at a median of 22 (interquartile range 9-29) days and 10 (8-16) months after the first revascularized MI. Transmural MI was defined as ≥75% enhancement in at least one myocardial segment.

RESULTS

Peak CK-MB was 86 (40-216) μg/L in median, while recovery and chronic phase scar size were 13 (3-23) % and 8 (2-19) %. Altogether 33 patients (81%) had a non-transmural MI. Peak CK-MB had a strong correlation with recovery and chronic scar size (r ≥ 0.80 for all, r ≥ 0.74 for non-transmural MIs; p < 0.001). Peak CK-MB, recovery scar size, and chronic scar size, were all strongly correlated with chronic wall motion abnormality index (WMAi) (r ≥ 0.75 for all, r ≥ 0.73 for non-transmural MIs; p < 0.001). There was proportional scar size and LV mass resorption of 26% (0-50%) and 6% (- 2-14%) in median. Young age (< 60 years, median) was associated with greater LV mass resorption (median 9%vs.1%, p = 0.007).

CONCLUSIONS

Peak CK-MB has a strong association with chronic scar size and wall motion abnormalities after revascularized non-transmural MI. Considerable infarct resorption happens after the first-month recovery phase. LV mass resorption is related to age, being more common in younger patients.

Left ventricular mechanical dispersion is associated with nonsustained ventricular tachycardia in hypertrophic cardiomyopathy

OBJECTIVE

We assessed the value of speckle tracking two-dimensional (2D) strain echocardiography (2DSE) measured mechanical dispersion (MD) with other imaging and electrocardiographic parameters in differentiating hypertrophic cardiomyopathy (HCM) patients with and without nonsustained ventricular tachycardia (NSVT) on 24-h ambulatory ECG monitoring.

METHODS AND RESULTS

We studied 31 patients with HCM caused by the Finnish founder mutation MYBPC3-Q1061X and 20 control subjects with comprehensive 2DSE echocardiography and cardiac magnetic resonance imaging (CMRI). The presence of NSVT was assessed from ambulatory 24-h ECG monitoring. NSVT episodes were recorded in 11 (35%) patients with HCM. MD was significantly higher in HCM patients with NSVT (93 ± 41 ms) compared to HCM patients without NSVT (50 ± 18 ms, p = 0.012) and control subjects (41 ± 16 ms, p < 0.001). MD was the only variable independently associated with the presence of NSVT (OR: 1.60, 95% CI: 1.05-2.45, p = 0.030). Assessed by ROC curves, MD performed best in differentiating between HCM patients with and without NSVT (AUC = 0.81).

CONCLUSIONS

Increased mechanical dispersion was associated with NSVT in HCM patients on 24-h ambulatory ECG monitoring. Key messages The prediction of sudden cardiac death in hypertrophic cardiomyopathy remains a challenge and novel imaging methods are required to identify individuals at risk of malignant ventricular arrhythmias. Mechanical dispersion by speckle tracking echocardiography is associated with NSVT on 24-h ambulatory ECG monitoring in patients with hypertrophic cardiomyopathy.

Magnetic Resonance Imaging of the Failing Heart

Validated cardiovascular magnetic resonance imaging procedures are available for assessment of myocardial functional and perfusion reserve, viability and extent of infarction. The techniques still under development provide opportunities for further research of both new treatment strategies and magnetic resonance imaging.

Cardiovascular magnetic resonance of mitral valve length in hypertrophic cardiomyopathy

BACKGROUND

Previous data suggest that mitral valve leaflets are elongated in hypertrophic cardiomyopathy (HCM), and mitral valve leaflet elongation may constitute a primary phenotypic expression of HCM. Our objective was to measure the length of mitral valve leaflets by cardiovascular magnetic resonance (CMR) in subjects with HCM caused by a Finnish founder mutation in the myosin-binding protein C gene (MYBPC3-Q1061X), carriers of the same mutation without left ventricular hypertrophy, as well as in unselected consecutive patients with HCM, and respective controls.

METHODS

Anterior mitral valve leaflet (AML) and posterior mitral valve leaflet (PML) lengths were measured by CMR in 47 subjects with the Q1061X mutation in the gene encoding MYBPC3 and in 20 healthy relatives without the mutation. In addition, mitral valve leaflet lengths were measured by CMR in 80 consecutive non-genotyped patients with HCM in CMR and 71 age- and gender-matched healthy subjects.

RESULTS

Of the subjects with the MYBPC-Q1016X mutation, 32 had left ventricular hypertrophy (LVH, LV maximal wall thickness ≥ 13 mm in CMR) and 15 had no hypertrophy. PML was longer in patients with the MYBPC3-Q1061X mutation and LVH than in controls of the MYBPC group (12.8 ± 2.8 vs 10.6 ± 1.9 mm, P = 0.013), but the difference between the groups was not statistically significant when PML was indexed for BSA (P = 0.066), or when PML length was adjusted for BSA, age, gender, LV mass and ejection fraction (P = 0.195). There was no significant difference in the PML length in mutation carriers without LVH and controls (11.1 ± 3.4 vs 10.6 ± 1.9, P = 0.52). We found no difference in AML lengths between the MYBPC mutation carriers with or without hypertrophy and controls. In 80 consecutive non-genotyped patients with HCM, there was no difference either in AML or PML lengths in subjects with HCM compared to respective control subjects.

CONCLUSIONS

In subjects with HCM caused by the Q1061X mutation in the MYBPC3 gene, the posterior mitral valve leaflets may be elongated, but mitral valve elongation does not constitute primary phenotypic expression of the disease. Instead, elongated mitral valve leaflets seem to be associated with body size and left ventricular remodeling.

Biomarkers and prediction of myocardial triglyceride content in non-diabetic men

BACKGROUND AND AIMS

Lipid oversupply to cardiomyocytes or decreased utilization of lipids leads to cardiac steatosis. We aimed to examine the role of different circulating metabolic biomarkers as predictors of myocardial triglyceride (TG) content in non-diabetic men.

METHODS AND RESULTS

Myocardial and hepatic TG contents were measured with 1.5 T magnetic resonance (MR) spectroscopy, and LV function, visceral adipose tissue (VAT), abdominal subcutaneous tissue (SAT), epicardial and pericardial fat by MR imaging in 76 non-diabetic men. Serum concentration of circulating metabolic biomarkers [adiponectin, leptin, adipocyte-fatty acid binding protein 4 (A-FABP 4), resistin, and lipocalin-2] including β-hydroxybuturate (β-OHB) were measured. Subjects were stratified by tertiles of myocardial TG into low, moderate, and high myocardial TG content groups. Concentrations of β-OHB were lower (p = 0.003) and serum levels of A-FABP 4 were higher (p < 0.001) in the group with high myocardial TG content compared with the group with low myocardial TG content. β-OHB was negatively correlated with myocardial TG content (r = -0.316, p = 0.006), whereas A-FABP 4 was not correlated with myocardial TG content (r = 0.192, p = 0.103). In multivariable analyses β-OHB and plasma glucose levels were the best predictors of myocardial TG content independently of VAT and hepatic TG content. The model explained 58.8% of the variance in myocardial TG content.

CONCLUSION

Our data showed that β-OHB and fasting glucose were the best predictors of myocardial TG content in non-diabetic men. These data suggest that hyperglycemia and alterations in lipid oxidation may be associated with cardiac steatosis in humans.

B-Lines on Pediatric Lung Sonography: Comparison With Computed Tomography

OBJECTIVES

Sonographic artifacts known as B-lines can been used to estimate alterations of lung parenchyma. Multiple B-lines on sonography are seen in congestive heart disease, interstitial lung disease, respiratory infections, and neonates. The aim of this study was to compare the amount of B-lines on sonography to the extent of parenchymal changes on computed tomography (CT) in children.

METHODS

Lung sonography was performed on 60 patients aged 18 years and younger referred for chest CT at our institution. B-lines were counted from 5 anterolateral intercostal spaces bilaterally. The CT findings were documented and graded as absent, minimal, partial, or complete.

RESULTS

The number of B-lines on sonography increased consistently with the growing extent of parenchymal changes on CT. The differences in the B-line counts between the patients grouped according to the extent of parenchymal changes on CT were statistically significant except between patients with minimal and no changes (P < .01 Kruskal-Wallis and Tukey tests).

CONCLUSIONS

The number of B-lines on sonography correlates with the extent of parenchymal changes on CT. Various parenchymal changes were seen in patients with B-lines on sonography. B-lines were more frequently seen in patients with no changes on CT when imaged during general anesthesia.

Intraosseous access in neonates and infants: risk of severe complications - a case report

Gaining vascular access in a neonate during cardiopulmonary resuscitation is crucial and challenging. Intraosseous (IO) access can offer a fast and reliable method for achieving emergency access for fluids and drugs when venous access fails in a critically ill child. IO access can however result in rare, but serious adverse events including compartment syndrome and amputation. We describe a case resulting in leg amputation due to IO infusion in a neonate after resuscitation and therapeutic hypothermia. We compared 10 tibia X-rays in three age groups. The mean medullary diameter of the proximal tibia at the recommended site for IO access was 7 mm in neonate, 10 mm in 1- to 12-month-old infants, and 12 mm in 3- to 4-year-old children. This provides a narrow margin of safety for the correct positioning and the avoidance of dislodgement of the IO needle. The correct position of the IO needle should be confirmed by bone marrow aspiration and fluid bolus. Unnecessary touching of the IO needle after fixing it in place should be avoided by inserting a luer-lock catheter with a three-way stop-cock for IO drug and fluid administration. Regular observation of the circulation and possible swelling of the leg should be performed. The IO administration of inotropic infusions should also be avoided after the initial resuscitation phase. When treating with therapeutic hypothermia, it may be wise to remove the IO needle much earlier than the currently recommended 24 h because of the problems in peripheral circulation and its monitoring.

Combining FDG-PET and 99mTc-SPECT to predict functional outcome after coronary artery bypass surgery

AIMS

Single-photon emission computed tomography (SPECT) and positron emission tomography (PET) are suggested to improve clinical decision-making in ischaemic cardiomyopathy. Here, we present a unique cohort of patients who underwent nuclear medicine studies and cardiac magnetic resonance imaging (MRI) both before and 1 year after coronary artery bypass (CABG) surgery to assess benefit from surgery.

METHODS AND RESULTS

Before CABG, we applied three quantitative techniques using (18)F-fluorodeoxyglucose-PET and (99m)technetium-tetrofosmin-SPECT with a software tool to measure defects with hypoperfused but viable and non-viable myocardium in 15 patients. One method used solely PET, two others combined PET and SPECT at different thresholds. As a reference, we used change in left-ventricular (LV) function and volume by MRI. Preoperatively, ischaemic but viable areas detected by the method with a 10% threshold combining PET-SPECT and the PET-only method correlated significantly with preoperative regional wall thickening (WT; P = 0.03 and P = 0.005, respectively). When compared with global functional outcome (change in LV ejection fraction) and LV remodelling (change in end-diastolic volume) 1 year postoperatively, no correlation appeared with preoperative PET- or PET-SPECT-derived viable or non-viable tissue. Neither was any correlation observable between local change in WT and local preoperative defect size evaluated by any of these three methods.

CONCLUSION

Preoperatively, PET and PET-SPECT with 10% threshold detected dysfunctional myocardium, but all analysis methods failed to predict 1-year functional outcome assessed by MRI. In patients with three-vessel disease and heart failure, SPECT perfusion and PET viability study results show substantial heterogeneity; this should be considered when selecting patients for revascularization.

Intramyocardial bone marrow mononuclear cell transplantation in ischemic heart failure: Long-term follow-up

BACKGROUND

Long-term results regarding treatment of chronic ischemic heart failure with bone marrow mononuclear cells (BMMCs) have been few. We received encouraging results at the 1-year follow-up of patients treated with combined coronary artery bypass grafting (CABG) and BMMCs, so we decided to extend the follow-up.

METHODS

The study patients had received injections of BMMCs or vehicle into the myocardial infarction border area during CABG in a randomized and double-blind manner. We could contact 36 of the 39 patients recruited for the original study. Pre-operatively and after an extended follow-up period, we performed magnetic resonance imaging, measured pro-B-type amino-terminal natriuretic peptide, reviewed patient records from the follow-up period, and determined current quality of life with the Medical Outcomes Study Short-Form 36 (SF-36) Health Survey.

RESULTS

The median follow-up time was 60.7 months (interquartile range [IQR], 45.1-72.6 months). No statistically significant difference was detected in change of pro-B-type amino-terminal natriuretic peptide values or in quality of life between groups. The median change in left ventricular ejection fraction was 4.9% (IQR, -2.1% to 12.3%) for controls and 3.9% (IQR, -5.2% to 10.2%) for the BMMC group (p = 0.647). Wall thickening in injected segments increased by a median of 17% (IQR, -5% to 30%) for controls and 15% (IQR, -12% to 19%) for BMMC patients (p = 0.434). Scar size in injected segments increased by a median of 2% (IQR, -7% to 19%) for controls but diminished for BMMC patients, with a median change of -17% (IQR, -30% to -6%; p = 0.011).

CONCLUSIONS

In the treatment of chronic ischemic heart failure, combining intramyocardial BMMC therapy with CABG fails to affect cardiac function but can sustainably reduce scar size, even in the long-term.

Assessment of myocardial infarct size with body surface potential mapping: validation against contrast-enhanced cardiac magnetic resonance imaging

BACKGROUND

Assessment of myocardial infarct (MI) size is important for therapeutic and prognostic reasons. We used body surface potential mapping (BSPM) to evaluate whether single-lead electrocardiographic variables can assess MI size.

METHODS

We performed BSPM with 120 leads covering the front and back chest (plus limb leads) on 57 patients at different phases of MI: acutely, during healing, and in the chronic phase. Final MI size was determined by contrast-enhanced cardiac magnetic resonance imaging (DE-CMR) and correlated with various computed depolarization- and repolarization-phase BSPM variables. We also calculated correlations between BSPM variables and enzymatic MI size (peak CK-MBm).

RESULTS

BSPM variables reflecting the Q- and R wave showed strong correlations with MI size at all stages of MI. R width performed the best, showing its strongest correlation with MI size on the upper right back, there representing the width of the "reciprocal Q wave" (r = 0.64-0.71 for DE-CMR, r = 0.57-0.64 for CK-MBm, P < 0.0001). Repolarization-phase variables showed only weak correlations with MI size in the acute phase, but these correlations improved during MI healing. T-wave variables and the QRSSTT integral showed their best correlations with DE-CMR defined MI size on the precordial area, at best r = -0.57, P < 0.0001 in the chronic phase. The best performing BSPM variables could differentiate between large and small infarcts at all stages of MI.

CONCLUSIONS

Computed, single-lead electrocardiographic variables can estimate the final infarct size at all stages of MI, and differentiate large infarcts from small.

Electrocardiographic changes associated with insulin resistance

BACKGROUND AND AIM

Cardiac steatosis has been related to increased risk of heart disease. We investigated the association between cardiac steatosis, electrocardiographic (ECG) abnormalities, and individual components of the metabolic syndrome (MetS).

METHODS AND RESULTS

A 12-lead ECG and laboratory data were examined in 31 men with the MetS and in 38 men without the MetS. Myocardial triglyceride (MTG) content was measured with 1.5 T magnetic resonance (MR) spectroscopy and epicardial and pericardial fat by MR imaging. MTG content, epicardial and pericardial fat depots were higher in men with the MetS compared with subjects without the MetS (p < 0.001). The heart rate was increased (p < 0.001), the PR interval was longer (p < 0.044), the frontal plane QRS axis shifted to the left (p < 0.001), and the QRS voltage (p < 0.001) was lower in subjects with the MetS. The frontal plane QRS axis and the QRS voltage were inversely correlated with MTG content, waist circumference (WC), body mass index (BMI), TGs, and fasting blood glucose. High-density lipoprotein cholesterol correlated positively and measures of insulin resistance negatively with the QRS voltage. MTG content and hypertriglyceridemia were determinants of the frontal plane QRS and WC and hyperglycemia were predictors of the QRS voltage.

CONCLUSION

The MetS and cardiac steatosis appear to associate with multiple changes on 12-lead ECG. The frontal plane QRS axis is shifted to the left and the QRS voltage is lower in subjects with the MetS. Standard ECG criteria may underestimate the presence of left ventricular hypertrophy in obese subjects with cardiometabolic risk factors.

Late gadolinium enhancement (LGE) progresses with right ventricle volume in children after repair of tetralogy of fallot

Background

Fibrosis after myocardial damage can be determined by cardiac magnetic resonance (CMR) with late gadolinium enhancement (LGE). We studied whether ventricular LGE is visible in the ventricles of pediatric and adolescent TOF (tetralogy of Fallot) patients by measuring LGE and investigating whether fibrosis correlated with right ventricular volume, pulmonary regurgitation, N-terminal pro-brain natriuretic peptide (NT-proBNP) or the aminoterminal propeptide of type III procollagen (PIIINP). We also studied if the patient's age, post-operative follow-up time or surgical history would affect LGE.

Methods

A total of 40 pediatric patients who had undergone TOF repair and 43 healthy age and gender matched controls underwent a CMR study, whereby LGE was scored in the right (RV) and the left ventricle. To exclude the possible iatrogenic scarring we calculated the LGE score by excluding the right ventricular outflow tract and VSD patch region.

Results

All patients had RV LGE and in 39 of 40 it was seen also outside the surgically affected areas. The amount of LGE correlated positively with the RV end-diastolic volume (r = 0.44, P = 0.0045), pulmonary regurgitation (r = 0.40, P = 0.013), and with NT-proBNP. The presence of LGE also depended on post-operative follow-up time (r = 0.53, P = 0.006). PIIINP levels of TOF patients were significantly higher than in the control subjects but it did not correlate with LGE or with any of the studied clinical markers.

Conclusions

LGE is present globally in the right ventricular muscle in children and adolescents with TOF. The longer the follow-up time the more common was the LGE in the right ventricle.

[Myocarditis in children--a diagnostic and therapeutic challenge]

Viral infections are the most common causes of myocarditis in children. Chronic myocardial injury may develop following an immune or autoimmune reaction triggered or maintained by an infection, or can be part of a systemic autoimmune disease. Although many of the children having developed myocarditis are symptomless, initial symptoms may include cardiac insufficiency, arrhythmias and sudden death. The diagnosis requires a clinical suspicion as well as laboratory and imaging studies. Recovery from myocarditises often takes place spontaneously, but some result in the development of dilated cardiomyopathy (DCM).

Cardiac steatosis and left ventricular function in men with metabolic syndrome

BACKGROUND

Ectopic accumulation of fat accompanies visceral obesity with detrimental effects. Lipid oversupply to cardiomyocytes leads to cardiac steatosis, and in animal studies lipotoxicity has been associated with impaired left ventricular (LV) function. In humans, studies have yielded inconclusive results. The aim of the study was to evaluate the role of epicardial, pericardial and myocardial fat depots on LV structure and function in male subjects with metabolic syndrome (MetS).

METHODS

A study population of 37 men with MetS and 38 men without MetS underwent cardiovascular magnetic resonance and proton magnetic spectroscopy at 1.5 T to assess LV function, epicardial and pericardial fat area and myocardial triglyceride (TG) content.

RESULTS

All three fat deposits were greater in the MetS than in the control group (p <0.001). LV diastolic dysfunction was associated with MetS as measured by absolute (471 mL/s vs. 667 mL/s, p = 0.002) and normalized (3.37 s⁻¹ vs. 3.75 s⁻¹, p = 0.02) LV early diastolic peak filling rate and the ratio of early diastole (68% vs. 78%, p = 0.001). The amount of epicardial and pericardial fat correlated inversely with LV diastolic function. However, myocardial TG content was not independently associated with LV diastolic dysfunction.

CONCLUSIONS

In MetS, accumulation of epicardial and pericardial fat is linked to the severity of structural and functional alterations of the heart. The role of increased intramyocardial TG in MetS is more complex and merits further study.

Cardiac steatosis associates with visceral obesity in nondiabetic obese men

BACKGROUND

Liver fat and visceral adiposity are involved in the development of the metabolic syndrome (MetS). Ectopic fat accumulation within and around the heart has been related to increased risk of heart disease. The aim of this study was to explore components of cardiac steatosis and their relationship to intra-abdominal ectopic fat deposits and cardiometabolic risk factors in nondiabetic obese men.

METHODS

Myocardial and hepatic triglyceride (TG) contents were measured with 1.5 T magnetic resonance spectroscopy, and visceral adipose (VAT), abdominal subcutaneous tissue (SAT), epicardial and pericardial fat by magnetic resonance imaging in 37 men with the MetS and in 40 men without the MetS.

RESULTS

Myocardial and hepatic TG contents, VAT, SAT, epicardial fat volumes, and pericardial fat volumes were higher in men with the MetS compared with subjects without the MetS (P < .001). All components of cardiac steatosis correlated with SAT, VAT, and hepatic TG content and the correlations seemed to be strongest with VAT. Myocardial TG content, epicardial fat, pericardial fat, VAT, and hepatic TG content correlated with waist circumference, body mass index, high-density lipoprotein cholesterol TGs, very low-density lipoprotein-1 TGs, and the insulin-resistance homeostasis model assessment index. VAT was a predictor of TGs, high-density lipoprotein cholesterol, and measures of glucose metabolism, whereas age and SAT were determinants of blood pressure parameters.

CONCLUSIONS

We suggest that visceral obesity is the best predictor of epicardial and pericardial fat in abdominally obese subjects. Myocardial TG content may present a separate entity that is influenced by factors beyond visceral adiposity.

Delayed lung liquid absorption after cesarean section at term

BACKGROUND

Delayed postnatal removal of lung liquid may result in respiratory distress, which is more common in infants born by cesarean section. Vertical artefacts (B-lines) arising from the lung surface in lung ultrasound have been shown to correlate with the liquid content of the lungs.

OBJECTIVES

We studied whether lung ultrasound could be used for the assessment of postnatal lung liquid in healthy term infants born vaginally and by cesarean section.

METHODS

Lung ultrasound was performed 1, 3 and 24 h after birth to 22 vaginally born infants and 20 infants born by elective cesarean section. The abundance of B-lines was scored for each infant and time point by two independent observers blinded to the mode of delivery and time point on the examination on a five-step scale.

RESULTS

In both groups, a significant decrease in abundance of B-lines, indicative of lung liquid absorption, was observed during the first 24 h. 3 h after birth cesarean section was associated with significantly higher lung liquid content than vaginal delivery.

CONCLUSION

The noninvasive bedside ultrasound method for estimation of lung liquid is a promising tool for the early identification of infants at risk for pulmonary maladaptation.

Late gadolinium enhanced cardiovascular magnetic resonance of lamin A/C gene mutation related dilated cardiomyopathy

BACKGROUND

The purpose of this study was to identify early features of lamin A/C gene mutation related dilated cardiomyopathy (DCM) with cardiovascular magnetic resonance (CMR). We characterise myocardial and functional findings in carriers of lamin A/C mutation to facilitate the recognition of these patients using this method. We also investigated the connection between myocardial fibrosis and conduction abnormalities.

METHODS

Seventeen lamin A/C mutation carriers underwent CMR. Late gadolinium enhancement (LGE) and cine images were performed to evaluate myocardial fibrosis, regional wall motion, longitudinal myocardial function, global function and volumetry of both ventricles. The location, pattern and extent of enhancement in the left ventricle (LV) myocardium were visually estimated.

RESULTS

Patients had LV myocardial fibrosis in 88% of cases. Segmental wall motion abnormalities correlated strongly with the degree of enhancement. Myocardial enhancement was associated with conduction abnormalities. Sixty-nine percent of our asymptomatic or mildly symptomatic patients showed mild ventricular dilatation, systolic failure or both in global ventricular analysis. Decreased longitudinal systolic LV function was observed in 53% of patients.

CONCLUSIONS

Cardiac conduction abnormalities, mildly dilated LV and depressed systolic dysfunction are common in DCM caused by a lamin A/C gene mutation. However, other cardiac diseases may produce similar symptoms. CMR is an accurate tool to determine the typical cardiac involvement in lamin A/C cardiomyopathy and may help to initiate early treatment in this malignant familiar form of DCM.

Serum lipidomics meets cardiac magnetic resonance imaging: profiling of subjects at risk of dilated cardiomyopathy

Dilated cardiomyopathy (DCM), characterized by left ventricular dilatation and systolic dysfunction, constitutes a significant cause for heart failure, sudden cardiac death or need for heart transplantation. Lamin A/C gene (LMNA) on chromosome 1p12 is the most significant disease gene causing DCM and has been reported to cause 7-9% of DCM leading to cardiac transplantation. We have previously performed cardiac magnetic resonance imaging (MRI) to LMNA carriers to describe the early phenotype. Clinically, early recognition of subjects at risk of developing DCM would be important but is often difficult. Thus we have earlier used the MRI findings of these LMNA carriers for creating a model by which LMNA carriers could be identified from the controls at an asymptomatic stage. Some LMNA mutations may cause lipodystrophy. To characterize possible effects of LMNA mutations on lipid profile, we set out to apply global serum lipidomics using Ultra Performance Liquid Chromatography coupled to mass spectrometry in the same LMNA carriers, DCM patients without LMNA mutation and controls. All DCM patients, with or without LMNA mutation, differed from controls in regard to distinct serum lipidomic profile dominated by diminished odd-chain triglycerides and lipid ratios related to desaturation. Furthermore, we introduce a novel approach to identify associations between the molecular lipids from serum and the MR images from the LMNA carriers. The association analysis using dependency network and regression approaches also helped us to obtain novel insights into how the affected lipids might relate to cardiac shape and volume changes. Our study provides a framework for linking serum derived molecular markers not only with clinical endpoints, but also with the more subtle intermediate phenotypes, as derived from medical imaging, of potential pathophysiological relevance.

Compliance of the aorta in two diseases affecting vascular elasticity, familial hypercholesterolemia and diabetes: a MRI study

Arterial elasticity changes in familial hypercholesterolemia (FH) and diabetes mellitus (DM) with different but overlapping mechanisms. We compared aortic elasticity between 19 FH patients with the same mutation, 18 type 2 DM patients, and 30 controls, all aged 48 to 64. They underwent aortic magnetic resonance imaging, risk-factor assessment, and carotid and femoral ultrasound measurements. All patients were on adequate cardiovascular medication including statins and had established coronary heart disease (CHD). FH patients had longer-duration CHD (13.3 +/- 7.7 years) than did DM patients (5.0 +/- 3.1). Aortic compliance in the descending thoracic (DM 0.38 +/- 0.14 vs control 0.53 +/- 0.19, P = 0.032) and abdominal aorta (DM 0.45 +/- 0.20 vs control 0.66 +/- 0.25, P = 0.011) was lower in DM patients than in controls, whereas no significant difference existed between FH patients and controls. Carotid and femoral intima-media thickness was greater in FH and DM patients than in controls with no difference between patient groups. Carotid or femoral plaques appeared in 15 (79%) FH and in 10 (56%) DM patients. One control had a femoral plaque. Five FH patients showed stenosis, occlusion or both in carotid arteries. In our opinion, DM patients' lower compliance reflect mainly arterial media affecting arteriosclerosis, while FH patients' plaque status and longer duration of CHD suggest more advanced atherosclerosis. The FH patients may therefore be at increased risk for atherothrombotic events. However, due to small patient material, larger confirmatory studies are needed.

Aorta of young and middle-aged heterozygous familial hypercholesterolemia patients shows no functional or morphological impairment assessed by MRI

In familial hypercholesterolemia (FH) the level of LDL cholesterol is 2–3 times that of the normal population and leads to accelerated atherosclerosis. Improved care for risk factors has decreased cardiovascular mortality of these patients. We studied subclinical atherosclerotic changes with morphologic and functional aortic magnetic resonance imaging (MRI) in FH patients under the age of 50. 39 DNA test-verified heterozygous FH-North Karelia patients, aged 6–48, 28 of them treated with statins, and 25 healthy controls, aged 12 to 50, underwent aortic MRI, carotid ultrasound (US), and risk-factor assessment. No differences in any of the morphologic or functional aortic parameters appeared between patients and controls. Age and gender were independent predictors of the majority of the morphologic and functional measures. Carotid intima-media thickness assessed by US was greater in patients (0.57 mm ± 0.13 vs 0.48 ± 0.13 mm, p = 0.005) as was cholesterol-years score (243 ± 122 vs 137 ± 74, p < 0.001). Patients had thicker intima-media of the common carotid artery and higher cholesterol burden as indicated by their cholesterol-years score. Despite this, no differences existed in morphologic or functional aortic parameters assessed with MRI. The improved care of cardiovascular risk factors, especially statin treatment, may protect the aorta of FH patients. However, larger confirmatory studies are needed.

Comparison of current density viability imaging at rest with FDG-PET in patients after myocardial infarction

The assessment of myocardial viability is a major diagnostic challenge in patients with coronary artery disease (CAD) after myocardial infarction. Novel threedimensional current density (CD) imaging algorithms use high-resolution magnetic field mapping to determine the electrical activity of myocardial segments at rest. We, for the first time, compared CD activity obtained with several algorithms to 18-F-fluoro-deoxyglucose positron emission tomography (FDG-PET) in evaluation of myocardial viability. Magnetic field maps were obtained in nine adult patients (pt) with CAD and a history of infarction. The criterion for non-viable myocardium was an FDG-PET uptake with less than 45% of the maximum in the respective segments. CD imaging was applied to the left ventricle by using six different methods to solve the inverse problem. Mean CD activity was calculated for a close meshed grid of 90 locations of the left ventricle. A cardiologist compared bull's eye plots of CD and FDG-PET activity by eye. Spearman's correlation coefficients and specificity at a given level of sensitivity (70%) were calculated. Bull's eye plots revealed a significant correlation of CD/PET in 5 pt and no correlation in 3 pt. One pt had a negative correlation. The six different CD reconstruction methods performed similar. While CD reconstruction has the principal potential to image viable myocardium, we found that the reconstructed CD magnitude was low in scar segments but also reduced in some segments with preserved metabolic activity under resting conditions. New vector measurement techniques, the use of additional stress testing and advances in mathematical methodology are expected to improve CD imaging in future.

Methods of artificial enlargement of the training set for statistical shape models

Due to the small size of training sets, statistical shape models often over-constrain the deformation in medical image segmentation. Hence, artificial enlargement of the training set has been proposed as a solution for the problem to increase the flexibility of the models. In this paper, different methods were evaluated to artificially enlarge a training set. Furthermore, the objectives were to study the effects of the size of the training set, to estimate the optimal number of deformation modes, to study the effects of different error sources, and to compare different deformation methods. The study was performed for a cardiac shape model consisting of ventricles, atria, and epicardium, and built from magnetic resonance (MR) volume images of 25 subjects. Both shape modeling and image segmentation accuracies were studied. The objectives were reached by utilizing different training sets and datasets, and two deformation methods. The evaluation proved that artificial enlargement of the training set improves both the modeling and segmentation accuracy. All but one enlargement techniques gave statistically significantly (p < 0.05) better segmentation results than the standard method without enlargement. The two best enlargement techniques were the nonrigid movement technique and the technique that combines principal component analysis (PCA) and finite element model (FEM). The optimal number of deformation modes was found to be near 100 modes in our application. The active shape model segmentation gave better segmentation accuracy than the one based on the simulated annealing optimization of the model weights.

Myocardial function in patients with Shwachman-Diamond syndrome: aspects to consider before stem cell transplantation

BACKGROUND

Early studies have suggested increased risk of fatal cardiac complications in infants with Shwachman-Diamond syndrome (SDS), an inherited bone marrow failure syndrome. Patients undergoing stem cell transplantation (STC) have appeared susceptible to organ toxicity, including cardiac involvement.

PROCEDURE

This study assessed anatomical and functional features of the heart in SDS. Eight patients (mean age 24.1 years, range 7-37 years, seven males) with SDS and confirmed SBDS mutations were prospectively assessed for cardiac anatomy, myocardial wall properties, and systolic and diastolic function. The study protocol included conventional echocardiography (n = 8) complemented by exercise Tissue-Doppler echocardiography (n = 7), and by MRI (n = 6).

RESULTS

No abnormalities in cardiac anatomy or function were observed in baseline clinical assessment, EKG, or conventional echocardiographic and MRI measurements. Myocardial structure and left ventricular (LV) mass were normal. The maximum isovolumic acceleration (IVA) value during exercise in Tissue-Doppler was significantly lower (P < 0.001), and the right ventricular (RV) ejection fraction (P = 0.02) and peak filling rate (PFR, P = 0.008) at rest in MRI were higher in patients.

CONCLUSIONS

Children and young adults with SDS and mutations in SBDS had normal cardiac anatomy and myocardial structure. Subtle RV diastolic function alterations at rest and depressed LV contractility during exercise were observed. Further studies are warranted to evaluate the clinical importance of these findings.

Tissue Doppler strain-mapping in the assessment of the extent of chronic myocardial infarction: validation using magnetic resonance imaging

AIMS

The distribution of myocardial strain values can be visualized by colour-coded strain images. We examined for the first time if this strain-mapping function can be used to study the extent of prior myocardial infarction.

METHODS AND RESULTS

Echocardiography and cardiac magnetic resonance imaging with delayed contrast enhancement were performed in 26 patients with chronic myocardial infarction. Two-dimensional strain images of the left ventricle were obtained in all standard apical views. Myocardial segments (n = 416) were assigned a score ranging from one to four based on the strain-coded colour of the segment, with higher scores representing worse myocardial function. Strain-mapping scores and quantitative strain values averaged, respectively, 1.3 +/- 0.6 and -16.4 +/- 7.6% in segments without infarction, 1.7 +/- 1.0 and -15.0 +/- 8.6% in non-transmural infarctions, and 2.8 +/- 1.2 and -6.5 +/- 8.6% in transmural infarctions. Strain-mapping had a sensitivity of 60% and a specificity of 95% in detecting segments with transmural myocardial infarction. Corresponding values for echocardiographic wall motion analysis were 50 and 96%. Strain-mapping was possible in 80% of the segments and inter-observer agreement was substantial (kappa = 0.63).

CONCLUSION

Strain-mapping is a clinically applicable method for the assessment of regional myocardial function in post-myocardial infarction patients. Strain-mapping has reasonable feasibility and is more sensitive in detecting infarction damage than routine wall motion analysis.

Statin-treated familial hypercholesterolemia patients with coronary heart disease and pronounced atherosclerosis do not have more brain lesions than healthy controls in later middle age

BACKGROUND

Clinically silent brain lesions detected with magnetic resonance imaging (MRI) are associated with increased risk for stroke, while stroke risk is controversial in familial hypercholesterolemia (FH).

PURPOSE

To determine whether the occurrence and size of clinically silent brain lesions in FH patients with coronary heart disease (CHD) is higher than in neurologically healthy controls without CHD.

MATERIAL AND METHODS

Brain MRI (1.5T) was performed on 19 DNA-test-verified FH patients with CHD and on 29 cardiovascularly and neurologically healthy controls, all aged 48 to 64 years. All patients were on cardiovascular medication. Intracranial arteries were evaluated by MR angiography. Infarcts, including lacunas, and white matter T2 hyperintensities (WMHI), considered as signs of small vessel disease, were recorded. A venous blood sample was obtained for assessment of risk factors. Carotid and femoral intima-media thicknesses (IMT), assessed with ultrasound, were indicators of overall atherosclerosis.

RESULTS

On intracranial MR angiography, three patients showed irregular walls or narrowed lumens in intracranial carotid arteries. No silent infarcts appeared, and no differences in numbers or sizes of WMHIs between groups were recorded. Patients had greater carotid and femoral IMTs, and a greater number of carotid and femoral plaques. Cholesterol-years score, level of low-density lipoprotein (LDL) cholesterol, and level of high-sensitivity C-reactive protein (hsCRP) of the FH-North Karelia patients were higher than those of the controls, while the level of high-density lipoprotein (HDL) cholesterol in controls was higher.

CONCLUSION

FH patients with CHD and adequate cardiovascular risk-factor treatment showed no difference in the amount or size of clinically silent brain lesions compared to controls, despite patients' more severe atherosclerosis.

Artificially enlarged training set in image segmentation

Due to small training sets, statistical shape models constrain often too much the deformation in medical image segmentation. Hence, an artificial enlargement of the training set has been proposed as a solution for the problem. In this paper, the error sources in the statistical shape model based segmentation were analyzed and the optimization processes were improved. The method was evaluated with 3D cardiac MR volume data. The enlargement method based on non-rigid movement produced good results--with 250 artificial modes, the average error for four-chamber model was 2.11 mm when evaluated using 25 subjects.