Showing papers on "Cardiac magnetic resonance imaging published in 2008"

Left ventricular volume measurement with echocardiography: a comparison of left ventricular opacification, three-dimensional echocardiography, or both with magnetic resonance imaging

Abstract: Aims Both contrast enhanced (CE) two-dimensional echocardiography (2DE) and three-dimensional echocardiography (3DE) have been proposed as techniques to improve the accuracy of left ventricular (LV) volume measurements. We sought to examine the accuracy of non-contrast (NC) and CE-2DE and 3DE for calculation of LV volumes and ejection fraction (EF), relative to cardiac magnetic resonance imaging (MRI). Methods and results We studied 50 patients (46 men, age 63 ± 10 year) with past myocardial infarction who underwent echocardiographic assessment of LV volume and function. All patients sequentially underwent NC-2DE followed by NC-3DE. CE-2DE and CE-3DE were acquired during contrast infusion. Resting echocardiographic image quality was evaluated on the basis of NC-2DE. The mean LV end-diastolic volume (LVEDV) of the group by MRI was 207 ± 79 mL and was underestimated by 2DE (125 ± 54 mL, P = 0.005), and less by CE-2DE (172 ± 58 mL, P = 0.02) or 3DE (177 ± 64 mL, P = 0.08), but EDV was comparable by CE-3DE (196 ± 69 mL, P = 0.16). Limits of agreement with MRI were similar for NC-3DE and CE-2DE, with the best results for CE-3D. Results were similar for calculation of LVESV. Patients were categorized into groups of EF (≤35, 35–50, >50%) by MRI. NC-2DE demonstrated a 68% agreement (kappa 0.45, P = 0.001), CE-2DE a 62% agreement (kappa 0.20, P = 136), NC-3DE a 74% agreement (kappa 0.39, P = 0.005) and CE-3DE an 80% agreement (kappa 0.56, P < 0.001). Conclusion CE-2DE is analogous to NC-3DE in accurate categorization of LV function. However, CE-3DE is feasible and superior to other NC- and CE-techniques in patients with previous infarction.

Cardiac magnetic resonance imaging of myocardial contrast uptake and blood flow in patients affected with idiopathic or familial dilated cardiomyopathy

Abstract: Idiopathic dilated cardiomyopathy (IDC) is characterized by left ventricular (LV) enlargement with systolic dysfunction, other causes excluded. When inherited, it represents familial dilated cardio...

Prevalence and pathophysiological mechanisms of elevated cardiac troponin I levels in a population-based sample of elderly subjects

Abstract: Aims To evaluate the prevalence of cardiac troponin I (cTnI) elevation in an elderly community population and the association of cTnI levels with cardiovascular risk factors, vascular inflammation, atherosclerosis, cardiac performance, and areas indicative of infarcted myocardium identified by cardiac magnetic resonance imaging. Methods and results cTnI elevation defined as cTnI levels >0.01 µg/L (Access AccuTnI, Beckman Coulter) was found in 21.8% of the study participants ( n = 1005). cTnI > 0.01 µg/L was associated with cardiovascular high-risk features, the burden of atherosclerosis in the carotid arteries, left-ventricular mass, and impaired left-ventricular systolic function. No associations were found between cTnI and inflammatory activity, diastolic dysfunction, or myocardial scars. Male gender (OR 1.6; 95% CI 1.1–2.4), ischaemic ECG changes (OR 1.7; 95% CI 1.1–2.7), and NT-pro-brain natriuretic peptide levels (OR 1.4; 95% CI 1.1–1.7) independently predicted cTnI > 0.01 µg/L. cTnI > 0.01 µg/L correlated also to an increased cardiovascular risk according to the Framingham risk score. Conclusion cTnI > 0.01 µg/L is relatively common in elderly subjects and is associated with cardiovascular high-risk features and impaired cardiac performance. Cardiac troponin determined by a highly sensitive assay might thus serve as an instrument for the identification of subjects at high cardiovascular risk in general populations.

Correspondence Between the 17-Segment Model and Coronary Arterial Anatomy Using Contrast-Enhanced Cardiac Magnetic Resonance Imaging

Abstract: Objectives The purpose of this study was to investigate the correspondence between the coronary arterial anatomy and supplied myocardium based on the proposed American Heart Association 17-segment model. Background Standardized assignment of coronary arteries to specific myocardial segments is currently based on empirical assumptions. Methods A cardiac magnetic resonance study was performed in 93 subjects following acute myocardial infarction treated with primary percutaneous coronary intervention. Two observers blindly reviewed all angiograms to examine the location of the culprit lesion and coronary dominancy. Two additional observers scored for the presence of cardiac magnetic resonance hyperenhancement (HE) on a 17-segment model. Segments were divided based on anatomical landmarks such as the interventricular grooves and papillary muscles. Results In a per-segment analysis, 23% of HE segments were discordant with the empirically assigned coronary distribution. Presence of HE in the basal anteroseptal, mid-anterior, mid-anteroseptal, or apical anterior wall was 100% specific for left anterior descending artery occlusion. The left anterior descending artery infarcts frequently involved the mid-anterolateral, apical lateral, and apical inferior walls. No segment was 100% specific for right coronary artery or left circumflex artery (LCX) occlusion, although HE in the basal anterolateral wall was highly specific (98%) for LCX occlusion. Combination of HE in the anterolateral and inferolateral walls was 100% specific for a LCX occlusion, and when extended to the inferior wall, was also 100% specific for a dominant or codominant LCX occlusion. Conclusions Four segments were completely specific for left anterior descending artery occlusion. No segment can be exclusively attributed to the right coronary artery or LCX occlusion. However, analysis of adjacent segments increased the specificity for a given coronary occlusion. These findings bring objective evidence in the appropriate segmentation of coronary arterial perfusion territories and assist accurate assignment of the culprit vessel in various imaging modalities.

Delayed contrast enhancement cardiac magnetic resonance imaging in trastuzumab induced cardiomyopathy

Abstract: Trastuzumab (Herceptin), an antagonist to the human epidermal growth factor 2 (HER2) receptor significantly decreases the rates of breast cancer recurrence and mortality by 50%. Despite therapeutic benefits, the risk of cardiotoxicity with trastuzumab ranges from 10–15% when administered sequentially following anthraycline chemotherapy. Little is known about the utility of cardiac magnetic resonance (CMR) in the assessment of trastuzumab mediated cardiomyopathy. Between 2005–2006 inclusive, 160 breast cancer patients were identified at a single tertiary care oncology centre. Of the total population, 10 patients (mean age 40 ± 8 years) were identified with trastuzumab induced cardiomyopathy, based on a LVEF less than 40% on serial MUGA or echocardiography. CMR was performed in all patients to determine LV volumes, systolic function and evidence of late gadolinium enhancement (LGE). At the time of diagnosis of trastuzumab induced cardiomyopathy, the mean LVEF was 29 ± 4%. Subepicardial linear LGE was present in the lateral portion of the left ventricles in all 10 patients. LGE-CMR is a novel way of detecting early changes in the myocardium due to trastuzumab induced cardiotoxicity.

In vivo T2-weighted magnetic resonance imaging can accurately determine the ischemic area at risk for 2-day-old nonreperfused myocardial infarction.

Abstract: Objectives:To determine whether in vivo T2-weighted cardiac magnetic resonance imaging (MRI) delineates the area at risk (AAR) in 2-day-old nonreperfused myocardial infarction (MI). AAR was defined as the size of the perfusion defect on day 0. MI and the residual ischemic viable border zone comprise

Quantitative assessment of left ventricular function with dual-source CT in comparison to cardiac magnetic resonance imaging: initial findings

Abstract: Cardiac magnetic resonance imaging and echocardiography are currently regarded as standard modalities for the quantification of left ventricular volumes and ejection fraction. With the recent introduction of dual-source computedtomography (DSCT), the increased temporal resolution of 83 ms should also improve the assessment of cardiac function in CT. The aim of this study was to evaluate the accuracy of DSCT in the assessment of left ventricular functional parameters with cardiac magnetic resonance imaging (MRI) as standard of reference. Fifteen patients (two female, 13 male; mean age 50.8 ± 19.2 years) underwent CT and MRI examinations on a DSCT (Somatom Definition; Siemens Medical Solutions, Forchheim, Germany) and a 3.0-Tesla MR scanner (Magnetom Trio; Siemens Medical Solutions), respectively. Multiphase axial CT images were analysed with a semiautomatic region growing algorithms (Syngo Circulation; Siemens Medical Solutions) by two independent blinded observers. In MRI, dynamic cine loops of short axis slices were evaluated with semiautomatic contour detection software (ARGUS; Siemens Medical Solutions) independently by two readers. End-systolic volume (ESV), end-diastolic volume (EDV), ejection fraction (EF) and stroke volume (SV) were determined for both modalities, and correlation coefficient, systematic error, limits of agreement and inter-observer variability were assessed. In DSCT, EDV and ESV were 135.8 ± 41.9 ml and 54.9 ± 29.6 ml, respectively, compared with 132.1 ± 40.8 ml EDV and 57.6 ± 27.3 ml ESV in MRI. Thus, EDV was overestimated by 3.7 ml (limits of agreement −46.1/+53.6), while ESV was underestimated by 2.6 ml (−36.6/+31.4). Mean EF was 61.6 ± 12.4% in DSCT and 57.9 ± 9.0% in MRI, resulting in an overestimation of EF by 3.8% with limits of agreement at −14.7 and +22.2%. Rank correlation rho values were 0.81 for EDV (P = 0.0024), 0.79 for ESV (P = 0.0031) and 0.64 for EF (P = 0.0168). The kappa value of inter-observer variability were amounted to 0.85 for EDV, ESV and EF. DSCT offers the possibility to quantify left ventricular function from coronary CT angiography datasets with sufficient diagnostic accuracy, adding to the value of the modality in a comprehensive cardiac assessment. The observed differences in the measured values may be due to different post-processing methods and physiological reactions to contrast material injection without beta-blocker medication.

Delayed enhancement cardiac magnetic resonance imaging reveals typical patterns of myocardial injury in patients with various forms of non-ischemic heart disease

Abstract: Background Late gadolinium-hyperenhancement (LHE) on cardiac Magnetic Resonance Imaging (CMR) has been linked to cardiovascular risk in ischemic and non-ischemic heart disease. We aimed to systematically categorize LHE-patterns in a variety of non-ischemic heart diseases (NIHD) and to explore their relationship with left ventricular (LV) function. Methods In a retrospective database search, 156 patients with NIHD who exhibited LHE on CMR were identified. All images were re-analyzed stepwise. LHE was correlated to LV functional parameters. Cardiac magnetic resonance (CMR) was conducted on 1.5 T scanners. Results Typically, LHE spared the subendocardium. Consistent LHE-patterns were observed in myocarditis, hypertrophic and dilated cardiomyopathy and systemic vasculitis. No conclusive LHE-patterns were observed in patients with aortic stenosis, arterial hypertension, lupus erythematosus, sarcoidosis, ventricular arrhythmia and in a mixed subgroup of rare NIHDs. There was no significant relationship between LHE and ejection fraction. There was no correlation between enddiastolic volume and LHE in either myocarditis (P = 0.13) or dilated cardiomyopathy (P = 0.62). LHE was unrelated to LV-mass in aortic stenosis (P = 0.13) and hypertrophic cardiomyopathy (P = 0.38). Conclusions Distinct LHE patterns exist in various NIHDs and their visualization may ultimately aid diagnosis. Unlike in ischemic heart disease, the structure-function relationship does not appear to be strong.

Onset of cardiac iron loading in pediatric patients with thalassemia major

Abstract: We reviewed cardiac T2* assessments from 77 thalassemia major patients between the ages of 2.5 and 18 years to study optimal timing of cardiac iron screening by magnetic resonance imaging. No patient under 9.5 years of age showed detectable cardiac iron in contrast to 36% of patients between the ages of 15–18 years old, corresponding to an odds-ratio of 1.28 (28%) per year. All patients with cardiac iron had received at least 35 grams of transfusional iron. Liver iron and ferritin failed to predict cardiac iron loading. Initiation of cardiac magnetic resonance imaging assessment should be determined according to age and transfusional burden rather than indices of iron overload. When appropriate chelation therapy has been administered since birth, cardiac magnetic resonance imaging can be postponed until 8 years of age when anesthesia is not required. Patients with suboptimal chelation, increased transfusional requirements, or who have initiated transfusions later in life should be tested sooner.

Prognostic Value of Normal Adenosine-Stress Cardiac Magnetic Resonance Imaging

Abstract: We investigated the prognostic value of normal adenosine stress cardiac magnetic resonance (CMR) in suspected coronary artery disease (CAD). Prospectively enrolled in the study were 218 patients with suspected CAD, no stress hypoperfusion, and no delayed enhancement in CMR, and consecutively deferred coronary angiography. The primary end point was a 12-month rate of major adverse cardiac events (MACE; cardiovascular mortality, myocardial infarction, revascularization, hospitalization due to cardiovascular event). CMR indication was symptomatic angina (Canadian Cardiovascular Society II in 42% and III in 7%) or evaluation of myocardial ischemia in patients with arrhythmia, syncope, and/or equivocal stress tests and cardiovascular risk factors (51%). As the main result, the 12-month MACE rate was 2/218 (1 stent implantation, 1 bypass surgery) and CMR negative predictive value 99.1%. There was no cardiac death or myocardial infarction. In conclusion, normal adenosine stress CMR predicts a very low MACE rate and an excellent 1-year prognosis in patients with suspected CAD. Our results provide clinical reassurance that patients at risk for CAD-associated MACE were not missed by CMR. Hence, CMR may serve as a reliable noninvasive gatekeeper to reduce the number of redundant coronary angiographies.

Catheter ablation of paroxysmal atrial fibrillation improves cardiac function: a prospective study on the impact of atrial fibrillation ablation on left ventricular function assessed by magnetic resonance imaging

Abstract: Aims Beneficial effects of atrial fibrillation (AF) ablation have been demonstrated in patients with congestive heart failure (CHF) and significantly impaired left ventricular ejection fraction (LVEF). However, the impact of pulmonary vein isolation (PVI) on cardiac function in patients with paroxysmal AF and impaired LVEF remains under discussion. This study aimed to evaluate the impact of PVI for paroxysmal AF on cardiac function in patients with impaired LVEF using cardiac magnetic resonance imaging (CMRI). Methods and results A total number of 70 patients with paroxysmal AF and episodes � 24 h were scanned on a 1.5-T-CMRI before and 6 months after PVI during sinus rhythm. End-diastolic volume, end-systolic volume, and LVEF were determined by epicardial and endocardial measurements. Patients were categorized into two groups regarding cardiac function as assessed by CMRI: group 1 patients (n ¼ 18) with an LVEF , 50% and patients with an LVEF . 50% (group 2, n ¼ 52). Group 1 patients demonstrated a significant lower success rate than patients of group 2 after a follow-up of 152+ 40 days (50 vs. 73%, P , 0.05). Cardiac magnetic resonance imaging in group 1 patients demonstrated a significant improvement in cardiac function after AF ablation (41+ 6v s. 51+ 12%, P ¼ 0.004), whereas group 2 patients did not show significant differences (60+ 6v s. 59+ 9%, P ¼ 0.22) after a 6 months follow-up. Conclusion Pulmonary vein isolation improves cardiac function in patients with paroxysmal AF and impaired LVEF. These data suggest that an impaired LV function can be partially attributed to AF with short-lasting paroxysms.

Characterisation of peripartum cardiomyopathy by cardiac magnetic resonance imaging

Abstract: Peripartum cardiomyopathy (PPCM) is a rare cause of heart failure. Only half of the patients recover normal cardiac function. We assessed the usefulness of magnetic resonance imaging (MRI) and late enhancement imaging to detect myocardial fibrosis in order to predict cardiac function recovery in patients with peripartum cardiomyopathy. Among a consecutive series of 1,037 patients referred for heart failure treatment or prognostic evaluation between 1999 and 2006, eight women had confirmed PPCM. They all underwent echocardiography and cardiac MRI for assessment of left ventricular anatomy, systolic function and detection of myocardial fibrosis through late enhancement imaging. Mean (± SD) baseline left ventricular ejection fraction (LVEF) was 28 ± 4%. After a follow-up of 50 ± 9 months, half the patients recovered normal cardiac function (LVEF = 58 ± 4%) and four did not (LVEF = 35 ± 6%). None of the eight patients exhibited abnormal myocardial late enhancement. No difference in MRI characteristics was observed between the two groups. Patients with PPCM do not exhibit a specific cardiac MRI pattern and particularly no myocardial late enhancement. It suggests that myocardial fibrosis does not play a major role in the limitation of cardiac function recovery after PPCM.

Value of real time three-dimensional echocardiography in patients with hypertrophic cardiomyopathy: comparison with two-dimensional echocardiography and magnetic resonance imaging.

Abstract: UNLABELLED Real time three-dimensional echocardiography (RT3DE) has been demonstrated to be an accurate technique to quantify left ventricular (LV) volumes and function in different patient populations. We sought to determine the value of RT3DE for evaluating patients with hypertrophic cardiomyopathy (HCM), in comparison with cardiac magnetic resonance imaging (MRI). METHODS We studied 20 consecutive patients with HCM who underwent two-dimensional echocardiography (2DE), RT3DE, and MRI. Parameters analyzed by echocardiography and MRI included: wall thickness, LV volumes, ejection fraction (LVEF), mass, geometric index, and dyssynchrony index. Statistical analysis was performed by Lin agreement coefficient, Pearson linear correlation and Bland-Altman model. RESULTS There was excellent agreement between 2DE and RT3DE (Rc = 0.92), 2DE and MRI (Rc = 0.85), and RT3DE and MRI (Rc = 0.90) for linear measurements. Agreement indexes for LV end-diastolic and end-systolic volumes were Rc = 0.91 and Rc = 0.91 between 2DE and RT3DE, Rc = 0.94 and Rc = 0.95 between RT3DE and MRI, and Rc = 0.89 and Rc = 0.88 between 2DE and MRI, respectively. Satisfactory agreement was observed between 2DE and RT3DE (Rc = 0.75), RT3DE and MRI (Rc = 0.83), and 2DE and MRI (Rc = 0.73) for determining LVEF, with a mild underestimation of LVEF by 2DE, and smaller variability between RT3DE and MRI. Regarding LV mass, excellent agreement was observed between RT3DE and MRI (Rc = 0.96), with bias of-6.3 g (limits of concordance = 42.22 to-54.73 g). CONCLUSION In patients with HCM, RT3DE demonstrated superior performance than 2DE for the evaluation of myocardial hypertrophy, LV volumes, LVEF, and LV mass.

Changes in Right Ventricular Structure and Function Assessed Using Cardiac Magnetic Resonance Imaging in Bosentan-Treated Patients With Pulmonary Arterial Hypertension

Abstract: Patients with pulmonary arterial hypertension (PAH) usually show improvements in symptoms, exercise capacity, and hemodynamics after treatment with approved medical therapies. This study sought to determine whether improvement in right-sided cardiac function measured using cardiac magnetic resonance imaging would also be seen and whether these changes would correlate with improvement in exercise capacity. Sixteen patients with PAH underwent evaluation at baseline and after 12 months of treatment with bosentan. After treatment, cardiac index, pulmonary vascular resistance, and 6-minute walk distance improved, and there was a trend toward improvement in right ventricular (RV) stroke volume (70 ± 27 to 81 ± 30 ml; p = 0.08), but no change in RV ejection fraction (RVEF) or RV end-diastolic volume. Six-minute walk distance improved by 59 m (p

Combined coronary and late-enhanced multidetector-computed tomography for delineation of the etiology of left ventricular dysfunction: comparison with coronary angiography and contrast-enhanced cardiac magnetic resonance imaging

Abstract: AIMS: To evaluate whether comprehensive evaluation of coronary anatomy and delayed enhancement (DE) by multidetector-computed tomography (MDCT) would allow determination of etiology of left ventricular dysfunction (LVD) as compared with coronary angiography (CA) and DE-magnetic resonance (CMR). METHODS AND RESULTS: Seventy-one consecutive patients (50 males, 59 +/- 16 years) with LVD (ejection fraction: 26 +/- 11%) of unknown etiology underwent MDCT, LGE (late Gd-DTPA-enhanced)-CMR and CA. Patients were classified into four groups according to coronary artery disease (CAD) by CA and LGE-CMR patterns. Patients (n = 24) with CAD and transmural or sub-endocardial DE by CMR were considered having definite ischaemic LVD (group 1). Patients (n = 36) without CAD by CA and with no/atypical LGE-CMR were considered non-ischaemic LVD (group 2). Further we identified four patients with transmural DE but no CAD (group 3) and seven patients with CAD but no DE (group 4). On per-patient basis, combined coronary and DE-MDCT had excellent agreement (kappa = 0.89; P < 0.001) with CA/LGE-CMR to classify patients into the same four groups. Sensitivity, specificity and accuracy of MDCT were 97, 92 and 94%, respectively for detecting patients with definite (group 1) or likely (groups 3 and 4) ischaemic LVD. CONCLUSION: Combined coronary and DE-MDCT can accurately differentiate ischaemic vs. non-ischaemic etiology of LVD.

Cardiac magnetic resonance imaging with pharmacological stress perfusion and delayed enhancement in asymptomatic patients with systemic sclerosis

Abstract: ### Objective. To assess cardiac involvement in asymptomatic patients with systemic sclerosis (SSc) by cardiac magnetic resonance imaging (MRI). ### Methods. Ten asymptomatic patients with SSc (all female; mean age 59.5 ± 9.4 yrs) underwent contrast enhanced cardiac MRI on a 1.5 T MRI device. Adenosine triphosphate was used for stress and rest perfusion to assess perfusion defects due to microvascular impairment or ischemia, and delayed enhanced (DE) imaging was obtained for the assessment of myocardial necrosis and fibrosis. We evaluated the pathophysiological associations of stress perfusion combined with DE imaging with SSc disease severity measures. ### Results. Stress perfusion defects were seen in 5 out of 9 patients (56%): 4 had nonsegmental subendocardial perfusion defects and one had a segmental subendocardial perfusion defect. Three patients were found to have DE. DE was not observed in any patient without perfusion defect; and among the 5 patients with perfusion defects, 3 (60%) had DE. Two of the 3 had DE in segments not matching the region of nonsegmental perfusion defects. The remaining one had a segmental subendocardial DE matching the region of a segmental perfusion defect. Perfusion defects were seen in 75% of patients with a history of digital ulceration compared to only 20% of those without history of ulceration. ### Conclusion. Subclinical myocardial involvement, as detected by cardiac MRI, was frequent in asymptomatic patients with SSc. Cardiac MRI may aid in understanding the pathophysiological mechanism of SSc.

Characterization of the structural and functional changes in the myocardium following focal ischemia-reperfusion injury

Abstract: High-resolution (11.7 T) cardiac magnetic resonance imaging (MRI) and histological approaches have been employed in tandem to characterize the secondary damage suffered by the murine myocardium fol...

Angiographic correlations of patients with small vessel disease diagnosed by adenosine-stress cardiac magnetic resonance imaging

Abstract: Cardiac magnetic resonance imaging (CMR) with adenosine-stress myocardial perfusion is gaining importance for the detection and quantification of coronary artery disease (CAD). However, there is little knowledge about patients with CMR-detected ischemia, but having no relevant stenosis as seen on coronary angiography (CA). The aims of our study were to characterize these patients by CMR and CA and evaluate correlations and potential reasons for the ischemic findings. 73 patients with an indication for CA were first scanned on a 1.5T whole-body CMR-scanner including adenosine-stress first-pass perfusion. The images were analyzed by two independent investigators for myocardial perfusion which was classified as subendocardial ischemia (n = 22), no perfusion deficit (n = 27, control 1), or more than subendocardial ischemia (n = 24, control 2). All patients underwent CA, and a highly significant correlation between the classification of CMR perfusion deficit and the degree of coronary luminal narrowing was found. For quantification of coronary blood flow, corrected Thrombolysis in Myocardial Infarction (TIMI) frame count (TFC) was evaluated for the left anterior descending (LAD), circumflex (LCX) and right coronary artery (RCA). The main result was that corrected TFC in all coronaries was significantly increased in study patients compared to both control 1 and to control 2 patients. Study patients had hypertension or diabetes more often than control 1 patients. In conclusion, patients with CMR detected subendocardial ischemia have prolonged coronary blood flow. In connection with normal resting flow values in CAD, this supports the hypothesis of underlying coronary microvascular impairment. CMR stress perfusion differentiates non-invasively between this entity and relevant CAD.

B-type natriuretic peptide and wall stress in dilated human heart.

Abstract: Background Although B-type natriuretic peptide (BNP) is used as complimentary diagnostic tool in patients with unknown thoracic disorders, many other factors appear to trigger its release. In particular, it remains unresolved to what extent cellular stretch or wall stress of the whole heart contributes to enhanced serum BNP concentration. Wall stress cannot be determined directly, but has to be calculated from wall volume, cavity volume and intraventricular pressure of the heart. The hypothesis was, therefore, addressed that wall stress as determined by cardiac magnetic resonance imaging (CMR) is the major determinant of serum BNP in patients with a varying degree of left ventricular dilatation or dysfunction (LVD). Methods A thick-walled sphere model based on volumetric analysis of the LV using CMR was compared with an echocardiography-based approach to calculate LV wall stress in 39 patients with LVD and 21 controls. Serum BNP was used as in vivo marker of a putatively raised wall stress. Nomograms of isostress lines were established to assess the extent of load reduction that is necessary to restore normal wall stress and related biochemical events. Results Both enddiastolic and endsystolic LV wall stress were correlated with the enddiastolic LV volume (r = 0.54, P 8 kPa: 587 +/- 648 pg/ml, P 12 kPa: 715 +/- 661 pg/ml, P < 0.001; normal < or =4 kPa: 124 +/- 203 pg/ml). Analysis of variance revealed LV enddiastolic wall stress as the only independent hemodynamic parameter influencing BNP (P < 0.01). Using nomograms with "isostress" curves, the extent of load reduction required for restoring normal LV wall stress was assessed. Compared with the CMR-based volumetric analysis for wall stress calculation, the echocardiography based approach underestimated LV wall stress particularly of dilated hearts. Conclusions In patients with LVD, serum BNP was increased over the whole range of stress values which were the only hemodynamic predictors. Cellular stretch appears to be a major trigger for BNP release. Biochemical mechanisms need to be explored which appear to operate over this wide range of wall stress values. It is concluded that the diagnostic use of BNP should primarily be directed to assess ventricular wall stress rather than the extent of functional ventricular impairment in LVD.

Myocardial scar detected by contrast-enhanced cardiac magnetic resonance imaging is associated with ventricular tachycardia in hypertrophic cardiomyopathy patients.

Abstract: Introduction Hypertrophic cardiomyopathy (HCM) is associated with myocardial scarring and ventricular tachycardia (VT). Contrast-enhanced cardiac magnetic resonance imaging (CE-CMR) can quantify myocardial scar, and scar imaging has been documented in patients with HCM. We investigated the assessment of myocardial scar in HCM patients using CE-CMR, and its correlation with proven VT. Methods Twenty-five patients (mean age 54±8) with HCM who underwent CE-CMR were identified, and clinical data obtained from chart review. Parameters of LV function were calculated from cine imaging, and myocardial scar was assessed using delayed enhancement imaging following gadolinium administration. Results Myocardial scar was detected in 16 (64%) patients with a mean mass 9±15g. Scar was patchy, mid-myocardial and located in the basal anteroseptum, and RV insertion sites. Scar was seen in septal, apical and concentric variants of HCM. Scar mass correlated with both LV Mass ( r 2 =0.74) and maximal LV wall thickness ( r 2 =0.42). VT occurred in 32% of patients, and was associated with both increased scar mass and wall thickness compared to non-VT patients (21±22g vs. 4±6g, and 2.4±0.5cm vs. 1.8±0.5cm, p 7g predicted the presence of VT with a sensitivity of 75% and specificity 82%. Conclusions Myocardial scar imaged by CE-CMR is common in patients with HCM, and is predictive of VT. Scar is seen in all HCM variants, and is associated with maximal wall thickness. There may be a role for CE-CMR in improved risk stratification for individual patients with HCM.

Non-surgical septal myocardial reduction by coil embolization for hypertrophic obstructive cardiomyopathy: early and 6 months follow-up

Abstract: Aims To evaluate the feasibility and the incidence of complete heart block (CHB) after non-surgical septal myocardial reduction by coil embolization in hypertrophic obstructive cardiomyopathy (HOCM). Methods and results Twenty patients with HOCM and drug-refractory symptoms underwent non-surgical myocardial septal reduction by coil embolization with detachable coils. Occlusion of septal perforator branches was successfully performed in all patients. We detected neither ventricular tachycardia nor CHB. One patient presented an interventricular septal defect after the procedure, and died 19 days later. Cardiac magnetic resonance imaging showed, in all patients, an increase in areas of hyperenhancement in the interventricular septum (IVS) compared with baseline. At 6-month follow-up, NYHA functional class and peak oxygen consumption were significantly improved compared with baseline (14.8 ± 4.5 vs. 18.5 ± 4.5 mL/kg/min; P = 0.001, respectively). Echocardiography showed a significant reduction of the IVS thickness and left ventricular outflow tract gradient (21 ± 3 vs. 17 ± 4 mm, P < 0.0001; 80 ± 29 to 35 ± 29 mmHg, P < 0.0001, respectively). Conclusion The results of this pilot non-randomized study suggest that non-surgical septal myocardial reduction by coil embolization in HOCM is feasible and does not induce CHB. Larger studies, ideally with a randomized comparison between coil embolization and alcohol septal ablation, are warranted.

Usefulness of Cardiac Magnetic Resonance Imaging Combined With Low-Dose Dobutamine Stress to Detect an Abnormal Ventricular Stress Response in Children and Young Adults After Fontan Operation at Young Age

Abstract: After Fontan operation, patients are limited in increasing cardiac output and in exercise capacity. This has been related to impaired preload or other factors leading to decreased global ventricular performance with stress. To study these factors, the stress responses of functionally univentricular hearts were assessed at rest and during low-dose dobutamine stress using cardiovascular magnetic resonance imaging. Thirty-two patients after Fontan completion at young age were included (27 with total cavopulmonary connection, 5 with atriopulmonary connection; mean age 13.3 years, range 7.5 to 22.2; 23 male patients; median follow-up after Fontan operation 8.1 years, range 5.2 to 17.8). A multiphase short-axis stack of 10 to 12 contiguous slices of the systemic ventricle was obtained at rest and during low-dose dobutamine stress cardiovascular magnetic resonance imaging (maximum 7.5 microg/kg/min). With stress-testing, heart rate, ejection fraction, and cardiac index increased adequately (p <0.001). There was an abnormal decrease in end-diastolic volume and an adequate decrease in end-systolic volume (p <0.001). Stroke volume did not change with stress testing (p = 0.15). At rest, dominant left ventricles had higher ejection fractions than dominant right ventricles (p = 0.01), but this difference disappeared with stress testing. In conclusion, a functionally univentricular heart after Fontan completion at young age has an adequate increase in ejection fraction with beta-adrenergic stimulation. However, as a result of impaired preload with stress, cardiac output can be increased only by increasing heart rate.

Characterization of patients with acute chest pain using cardiac magnetic resonance imaging.

Abstract: The purpose of this study was to evaluate whether CMRI provides characteristic findings in patients with acute chest pain suffering from ST-elevation-myocardial infarction (STEMI), non-ST-elevation myocardial infarction (NSTEMI), acute myocarditis or Tako-tsubo cardiomyopathy. 230 consecutive patients with acute chest pain underwent cardiac catheterization followed by CMRI within median 5 days. Patients were classified to suffer from STEMI (n = 102), NSTEMI (n = 89), acute myocarditis (n = 27), or Tako-tsubo cardiomyopathy (n = 12) on the synopsis of all clinical data. Wall motion abnormalities, late enhancement (LE), persistent microvascular obstruction as well ventricular volumes and functions were assessed by CMRI. Right and left ventricular volumes were significantly different between the groups and values were highest in patients with acute myocarditis. Wall motion abnormalities were observed in 100% of STEMI, 75% of NSTEMI, 67% of acute myocarditis and 100% of Tako-tsubo patients. There was a characteristic pattern of abnormal wall motion focused on midventricular-apical segments in patients with Tako-tsubo cardiomyopathy, depending on the culprit vessel in patients with STEMI/NSTEMI and with a random distribution in patients with acute myocarditis. LE was mainly subendocardial or transmural in patients with STEMI (93.2%) or NSTEMI (62.9%). LE was diffuse, intramural or subepicardial in patients with acute myocarditis. No LE was observed in patients with Tako-tsubo cardiomyopathy. Persistent microvascular obstruction was only visualized in patients with STEMI (33%) or NSTEMI (6%). Cardiac magnetic resonance imaging provides characteristic patterns of LE, persistent microvascular obstruction and wall motion abnormalities that allow a differentiation between patients with acute chest pain from coronary and non-coronary origin.