Mechanical effects of left ventricular midwall fibrosis in non-ischemic cardiomyopathy.

BACKGROUND: Left ventricular (LV) mid-wall fibrosis (MWF), which occurs in about a quarter of patients with non-ischemic cardiomyopathy (NICM), is associated with high risk of pump failure. The mid LV wall is the site of circumferential myocardial fibers. We sought to determine the effect of MWF on LV myocardial mechanics. METHODS: Patients with NICM (n = 116; age: 62.8 ± 13.2 years; 67% male) underwent late gadolinium enhancement cardiovascular magnetic resonance (CMR) and were categorized according to the presence (+) or absence (-) of MWF. Feature tracking (FT) CMR was used to assess myocardial deformation. RESULTS: Despite a similar LVEF (24.3 vs. 27.5%, p = 0.20), patients with MWF (32 [24%]) had lower global circumferential strain (Ɛcc: -6.6% vs. -9.4 %, P = 0.004), but similar longitudinal (Ɛll: -7.6 % vs. -9.4 %, p = 0.053) and radial (Ɛrr: 14.6% vs. 17.8% p = 0.18) strain. Compared with - MWF, + MWF was associated with reduced LV systolic, circumferential strain rate (-0.38 ± 0.1 vs. -0.56 ± 0.3 s(-1), p = 0.005) and peak LV twist (4.65 vs. 6.31°, p = 0.004), as well as rigid LV body rotation (64 % vs. 28 %, P <0.001). In addition, +MWF was associated with reduced LV diastolic strain rates (DSRcc: 0.34 vs. 0.46 s(-1); DSRll: 0.38 vs. 0.50s(-1); DSRrr: -0.55 vs. -0.75 s(-1); all p <0.05). CONCLUSIONS: MWF is associated with reduced LV global circumferential strain, strain rate and torsion. In addition, MWF is associated with rigid LV body rotation and reduced diastolic strain rates. These systolic and diastolic disturbances may be related to the increased risk of pump failure observed in patients with NICM and MWF.

The clinical outcome of cardiac resynchronization therapy in post-surgical valvular cardiomyopathy.

AIMS: Trials have shown that cardiac resynchronization therapy (CRT) is effective in patients with 'non-ischaemic cardiomyopathy'. Patients with post-surgical valvular cardiomyopathy (PSVCM) have been excluded from such trials. We sought to compare the clinical outcome of CRT in patients with PSVCM, idiopathic dilated cardiomyopathy (IDCM), or ischaemic cardiomyopathy (ICM). METHODS AND RESULTS: Clinical events and response to CRT were quantified in 556 patients (PSVCM = 38; IDCM = 165; ICM = 353) over 4.52 years [median, inter-quartile range (IQR): 4.42]. Response to CRT was defined as survival for ≥1 year free of hospitalizations plus improvement by ≥1 NYHA class or ≥25% in 6-min walking distance. Cardiac resynchronization therapy was initiated at 5.86 years (median, IQR: 9.86) after aortic valve replacement (73.7%) or mitral valve replacement/repair (44.7%). Compared with PSVCM, IDCM was associated with a lower total mortality [hazards ratio, HR: 0.54 (95% confidence interval, CI 0.34-0.84)], cardiac mortality [HR: 0.43 (95% CI 0.26-0.70)], and total mortality or major adverse cardiovascular events [HR: 0.57 (95% CI 0.37-0.87)], independent of known confounders. Compared with PSVCM, ICM was associated with a similar risk of death from pump failure [HR: 0.83 (95% CI 0.50-1.37)] and IDCM was associated with a lower risk [HR: 0.46 (95% CI 0.26-0.82)]. Response to CRT was similar across the groups. CONCLUSIONS: Compared with IDCM, PSVCM was associated with a worse outcome after CRT. Outcomes from PSVCM were similar to ICM. These findings indicate that PSVCM behaves very differently to IDCM after CRT.

Haemodynamic effects of cardiac resynchronization therapy using single-vein, three-pole, multipoint left ventricular pacing in patients with ischaemic cardiomyopathy and a left ventricular free wall scar: the MAESTRO study.

AIMS: The clinical response to cardiac resynchronization therapy (CRT) is variable. Multipoint left ventricular (LV) pacing could achieve more effective haemodynamic response than single-point LV pacing. Deployment of an LV lead over myocardial scar is associated with a poor haemodynamic response to and clinical outcome of CRT. We sought to determine whether the acute haemodynamic response to CRT using three-pole LV multipoint pacing (CRT3P-MPP) is superior to that to conventional CRT using single-site LV pacing (CRTSP) in patients with ischaemic cardiomyopathy and an LV free wall scar. METHODS AND RESULTS: Sixteen patients with ischaemic cardiomyopathy [aged 72.6 ± 7.7 years (mean ± SD), 81.3% male, QRS: 146.0 ± 14.2 ms, LBBB in 14 (87.5%)] in whom the LV lead was intentionally deployed straddling an LV free wall scar (assessed using cardiac magnetic resonance), underwent assessment of LV + dP/dtmax during CRT3P-MPP and CRTSP. Interindividually, the ΔLV + dP/dtmax in relation to AAI pacing with CRT3P-MPP (6.2 ± 13.3%) was higher than with basal and mid CRTSP (both P < 0.001), but similar to apical CRTSP. Intraindividually, significant differences in the ΔLV + dP/dtmax to optimal and worst pacing configurations were observed in 10 (62.5%) patients. Of the 8 patients who responded to at least one configuration, CRT3P-MPP was optimal in 5 (62.5%) and apical CRTSP was optimal in 3 (37.5%) (P = 0.0047). CONCLUSIONS: In terms of acute haemodynamic response, CRT3P-MPP was comparable an apical CRTSP and superior to basal and distal CRTSP. In the absence of within-device haemodynamic optimization, CRT3P-MPP may offer a haemodynamic advantage over a fixed CRTSP configuration.

Relationship of Right Ventricular Size and Function with Respiratory Status in Duchenne Muscular Dystrophy.

The relationship between pulmonary function and right ventricle (RV) in Duchenne muscular dystrophy (DMD) has not been evaluated. Using cardiac magnetic resonance (CMR), we describe the relationship of RV size and function with spirometry in a DMD cohort. Fifty-seven boys undergoing CMR and pulmonary function testing within 1 month at a single center (2013-2015) were enrolled. Comparisons of RV ejection fraction (RVEF) and end-diastolic volume index (RVEDVI) were made across categories of percent forced vital capacity (FVC%), and relationships were assessed. Mean age was 15.5 ± 3.5 years. Spirometry and CMR were performed within 3.9 ± 4.1 days. Median FVC% was 92.0 % (67.5-116.5 %). Twenty-three (40 %) patients had abnormal FVC% (<80 %) of which 13 (57 %) had mild (FVC% 60-79 %), 6 (26 %) had moderate (FVC% 40-59 %), and 4 (17 %) had severe (FVC <40 %) reductions. Mean RVEF was 58.3 ± 3.7 %. Patients with abnormal FVC% were older and had lower RVEF and RVEDVI. Both RVEF and RVEDVI were significantly associated with FVC% (r = 0.31, p = 0.02 and r = 0.39, p = 0.003, respectively). In a large DMD cohort, RVEF and RVEDVI were related to FVC%. Worsening respiratory status may guide monitoring of cardiac function in these patients.

Comparison of magnetic resonance feature tracking for systolic and diastolic strain and strain rate calculation with spatial modulation of magnetization imaging analysis.

PURPOSE: To compare cardiovascular magnetic resonance-feature tracking (CMR-FT) with spatial modulation of magnetization (SPAMM) tagged imaging for the calculation of short and long axis Lagrangian strain measures in systole and diastole. MATERIALS AND METHODS: Healthy controls (n = 35) and patients with dilated cardiomyopathy (n = 10) were identified prospectively and underwent steady-state free precession (SSFP) cine imaging and SPAMM imaging using a gradient-echo sequence. A timed offline analysis of images acquired at identical horizontal long and short axis slice positions was performed using CMR-FT and dynamic tissue-tagging (CIMTag2D). Agreement between strain and strain rate (SR) values calculated using these two different methods was assessed using the Bland-Altman technique. RESULTS: Across all participants, there was good agreement between CMR-FT and CIMTag for calculation of peak systolic global circumferential strain (-22.7 ± 6.2% vs. -22.5 ± 6.9%, bias 0.2 ± 4.0%) and SR (-1.35 ± 0.42 1/s vs. -1.22 ± 0.42 1/s, bias 0.13 ± 0.33 1/s) and early diastolic global circumferential SR (1.21 ± 0.44 1/s vs. 1.07 ± 0.30 1/s, bias -0.14 ± 0.34 1/s) at the subendocardium. There was satisfactory agreement for derivation of peak systolic global longitudinal strain (-18.1 ± 5.0% vs. -16.7 ± 4.8%, bias 1.3 ± 3.8%) and SR (-1.04 ± 0.29 1/s vs. -0.95 ± 0.32 1/s, bias 0.09 ± 0.26 1/s). The weakest agreement was for early diastolic global longitudinal SR (1.10 ± 0.40 1/s vs. 0.67 ± 0.32 1/s, bias -0.42 ± 0.40 1/s), although the correlation remained significant (r = 0.42, P < 0.01). CMR-FT generated these data over four times quicker than CIMTag. CONCLUSION: There is sufficient agreement between systolic and diastolic strain measures calculated using CMR-FT and myocardial tagging for CMR-FT to be considered as a potentially feasible and rapid alternative.

Myocardial Fibrosis Predicts Ventricular Arrhythmias and Sudden Death After Cardiac Electronic Device Implantation.

BACKGROUND: Increasing evidence supports a link between myocardial fibrosis (MF) and ventricular arrhythmias. OBJECTIVES: The purpose of this study was to determine whether presence of myocardial fibrosis on visual assessment (MFVA) and gray zone fibrosis (GZF) mass predicts sudden cardiac death (SCD) and ventricular fibrillation/sustained ventricular tachycardia after cardiac implantable electronic device (CIED) implantation. METHODS: In this prospective study, total fibrosis and GZF mass, quantified using cardiovascular magnetic resonance, was assessed in relation to the primary endpoint of SCD and the secondary, arrhythmic endpoint of SCD or ventricular arrhythmias after CIED implantation. RESULTS: Among 700 patients (age 68.0 ± 12.0 years), 27 (3.85%) experienced a SCD and 121 (17.3%) met the arrhythmic endpoint over median 6.93 years (IQR: 5.82-9.32 years). MFVA predicted SCD (HR: 26.3; 95% CI: 3.7-3,337; negative predictive value: 100%). In competing risk analyses, MFVA also predicted the arrhythmic endpoint (subdistribution HR: 19.9; 95% CI: 6.4-61.9; negative predictive value: 98.6%). Compared with no MFVA, a GZF mass measured with the 5SD method (GZF5SD) >17 g was associated with highest risk of SCD (HR: 44.6; 95% CI: 6.12-5,685) and the arrhythmic endpoint (subdistribution HR: 30.3; 95% CI: 9.6-95.8). Adding GZF5SD mass to MFVA led to reclassification of 39% for SCD and 50.2% for the arrhythmic endpoint. In contrast, LVEF did not predict either endpoint. CONCLUSIONS: In CIED recipients, MFVA excluded patients at risk of SCD and virtually excluded ventricular arrhythmias. Quantified GZF5SD mass added predictive value in relation to SCD and the arrhythmic endpoint.

Pain during cardiac implantable electronic device implantation.

In order to evaluate the extent and causes of pain during cardiac implantable electronic device (CIED) implantation in our hospital, a prospective audit over a 23-month period using a patient selfreporting questionnaire was undertaken. In total, 599 procedures were reported, 52.9% for de novo pacemaker implantation and 23.4% for high-energy devices (cardiac resynchronisation therapy defibrillator [CRT-D], implantable cardiac defibrillator [ICD], subcutaneous ICD). Overall, the median pain score was 2/10 (interquartile range 2-4). In total, 61.6% (367/599) reported no pain or mild pain (pain scores 0-3/10), 27.7% (165/599) reported moderate pain (pain score of 4-6/10) and 10.7% (64/599) reported severe pain (pain score of 7-10/10) during the procedure. Significant preimplant worry (odds ratio [OR] 2.13, 95% confidence interval [CI] 1.22 to 3.73) and higher lidocaine doses (OR 1.06, 95%CI 1.00 to 1.11) were associated with severe patient-reported pain. In conclusion, most patients underwent CIED implantation with minimum stress and maximum comfort. An important minority reported severe pain during the procedure. Optimising surgical technique and interventions targeted at reducing pre- and peri-implant worry, particularly in women, and especially in those receiving ICDs, warrants further investigation to reduce patient-reported pain during CIED implantation.

Long-Term Outcomes of Cardiac Resynchronization Therapy Using Apical Versus Nonapical Left Ventricular Pacing.

Background Experimental evidence indicates that left ventricular ( LV ) apical pacing is hemodynamically superior to nonapical LV pacing. Some studies have shown that an LV apical lead position is unfavorable in cardiac resynchronization therapy. We sought to determine whether an apical LV lead position influences cardiac mortality after cardiac resynchronization therapy. Methods and Results In this retrospective observational study, the primary end point of cardiac mortality was assessed in relation to longitudinal (basal, midventricular, or apical) and circumferential (anterior, lateral, or posterior) LV lead positions, as well as right ventricular (apical or septal), assigned using fluoroscopy. Lead positions were assessed in 1189 patients undergoing cardiac resynchronization therapy implantation over 15 years. After a median follow-up of 6.0 years (interquartile range: 4.4-7.7 years), an apical LV lead position was associated with lower cardiac mortality than a nonapical position (adjusted hazard ratio: 0.74; 95% confidence interval, 0.56-0.99) after covariate adjustment. There were no differences in total mortality or heart failure hospitalization. Death from pump failure was lower with apical than nonapical positions (adjusted hazard ratio: 0.69; 95% confidence interval, 0.51-0.94). Compared with a basal position, an apical LV position was also associated with lower risk of sudden cardiac death (adjusted hazard ratio: 0.34; 95% confidence interval, 0.13-0.93). No differences emerged between circumferential LV lead positions or right ventricular positions with respect to any end point. Conclusions In recipients of cardiac resynchronization therapy, an apical LV lead position was associated with better long-term cardiac survival than a nonapical position. This effect was due to a lower risk of pump failure and sudden cardiac death.

Molecular Hydrogen Yields from the α-Self-Radiolysis of Nitric Acid Solutions Containing Plutonium or Americium.

The yield of molecular hydrogen, as a function of nitric acid concentration, from the α-radiolysis of aerated nitric acid and its mixtures with sulfuric acid containing plutonium or americium has been investigated. Comparison of experimental measurements with predictions of a Monte Carlo radiation track chemistry model shows that, in addition to scavenging of the hydrated electron, its precursor, and the hydrogen atom, the quenching of excited state water is important in controlling the yield of molecular hydrogen. In addition, increases in solution acidity cause a significant change in the track reactions, which can be explained as resulting from scavenging of eaq- by Haq+ to form H•. Although plutonium has been shown to be an effective scavenger of precursors of molecular hydrogen below 0.1 mol dm-3 nitrate, previously reported effects of plutonium on G(H2)α between 1 and 10 mol dm-3 nitric acid were not reproduced. Modeling results suggest that plutonium is unlikely to effectively compete with nitrate ions in scavenging the precursors of molecular hydrogen at higher nitric acid concentrations, and this was confirmed by comparing molecular hydrogen yields from plutonium solutions with those from americium solutions. Finally, comparison between radionuclide, ion accelerator experiments, and model predictions leads to the conclusion that the high dose rate of accelerator studies does not significantly affect the measured molecular hydrogen yield. These reactions provide insight into the important processes for liquors common in the reprocessing of spent nuclear fuel and the storage of highly radioactive liquid waste prior to vitrification.

Plutonium and Americium Alpha Radiolysis of Nitric Acid Solutions.

The yield of HNO2, as a function of absorbed dose and HNO3 concentration, from the α-radiolysis of aerated HNO3 solutions containing plutonium or americium has been investigated. There are significant differences in the yields measured from solutions of the two different radionuclides. For 0.1 mol dm-3 HNO3 solutions, the radiolytic yield of HNO2 produced by americium α-decay is below the detection limit, whereas for plutonium α-decay the yield is considerably greater than that found previously for γ-radiolysis. The differences between the solutions of the two radionuclides are a consequence of redox reactions involving plutonium and the products of aqueous HNO3 radiolysis, in particular H2O2 and HNO2 and its precursors. This radiation chemical behavior is HNO3 concentration dependent with the differences between plutonium and americium α-radiolysis decreasing with increasing HNO3 concentration. This change may be interpreted as a combination of α-radiolysis direct effects and acidity influencing the plutonium oxidation state distribution, which in turn affects the radiation chemistry of the system.

Cardiac magnetic resonance tissue tracking in right ventricle: Feasibility and normal values.

PURPOSE: To investigate right ventricular (RV) strain in patients without identified cardiac pathology using cardiac magnetic resonance tissue tracking (CMR TT). METHODS: A total of 50 consecutive patients with no identified cardiac pathology were analyzed. RV longitudinal and circumferential strain was assessed by CMR TT. The age range was 4-81years with a median of 32years (interquartile range, 15 to 56years). RESULTS: Analysis time per patient was <5min. The peak longitudinal strain (Ell) was -22.11±3.51%. The peak circumferential strains (Ecc) for global, basal, mid-cavity and apical segments were as follows: -11.69±2.25%, -11.00±2.45%, -11.17±3.36%, -12.90±3.34%. There were significant gender differences in peak Ecc at the base (P=0.04) and the mid-cavity (P=0.03) with greater deformation in females than in males. On Bland-Altman analysis, peak Ell (mean bias, 0.22±1.67; 95% CI -3.05 to 3.49) and mid-cavity Ecc (mean bias, 0.036±1.75; 95% CI, -3.39 to 3.47) had the best intra-observer agreement and inter-observer agreement, respectively. CONCLUSIONS: RV longitudinal and circumferential strains can be quickly assessed with good intra-observer and inter-observer variability using TT.

Left ventricular lead position, mechanical activation, and myocardial scar in relation to left ventricular reverse remodeling and clinical outcomes after cardiac resynchronization therapy: A feature-tracking and contrast-enhanced cardiovascular magnetic resonance study.

BACKGROUND: Late mechanical activation (LMA) and viability in the left ventricular (LV) myocardium have been proposed as targets for LV pacing during cardiac resynchronization therapy (CRT). OBJECTIVE: The purpose of this study was to determine whether an LV lead position over segments with LMA and no scar improves LV reverse remodeling (LVRR) and clinical outcomes after CRT. METHODS: Feature-tracking and late gadolinium enhancement images were analyzed retrospectively in patients with heart failure (HF) (n = 89; mean age 66.8 ± 10.8 years; LV ejection fraction = 23.1% ± 9.9%) who underwent cardiovascular magnetic resonance (CMR) scanning before CRT implantation. Lead positions were classified as concordant (no scar and LMA [time to peak systolic circumferential strain]) or nonconcordant (scar and/or no LMA). RESULTS: LVRR occurred in 68% and 24% of patients with concordant and nonconcordant LV lead positions, respectively (P < .001). Over a median of 4.4 years (range 0.1-8.7 years), LV lead concordance predicted cardiac mortality (adjusted odds ratio [aOR] 0.27; 95% confidence interval [CI] 0.12-0.62) and cardiac mortality or HF hospitalizations (aOR 0.26, 95% CI 0.12-0.58). "No scar" in the paced segment predicted cardiac mortality (aOR 0.24; 95% CI 0.11-0.52) and cardiac mortality or HF hospitalizations (adjusted aOR 0.24; 95% CI 0.12-0.49). CONCLUSION: LV lead deployment over nonscarred LMA segments was associated with better LVRR and clinical outcomes after CRT. LVRR was primarily related to LMA, whereas events were primarily related to scar. These findings support the use of late gadolinium enhancement CMR and feature-tracking CMR in guiding LV lead deployment.

Cardiovascular Effects of Unilateral Nephrectomy in Living Kidney Donors.

UNLABELLED: There is a robust inverse graded association between glomerular filtration rate (GFR) and cardiovascular risk, but proof of causality is lacking. Emerging data suggest living kidney donation may be associated with increased cardiovascular mortality although the mechanisms are unclear. We hypothesized that the reduction in GFR in living kidney donors is associated with increased left ventricular mass, impaired left ventricular function, and increased aortic stiffness. This was a multicenter, parallel group, blinded end point study of living kidney donors and healthy controls (n=124), conducted from March 2011 to August 2014. The primary outcome was a change in left ventricular mass assessed by magnetic resonance imaging (baseline to 12 months). At 12 months, the decrease in isotopic GFR in donors was -30±12 mL/min/1.73m(2). In donors compared with controls, there were significant increases in left ventricular mass (+7±10 versus -3±8 g; P<0.001) and mass:volume ratio (+0.06±0.12 versus -0.01±0.09 g/mL; P<0.01), whereas aortic distensibility (-0.29±1.38 versus +0.28±0.79×10(-3) mm Hg(-1); P=0.03) and global circumferential strain decreased (-1.1±3.8 versus +0.4±2.4%; P=0.04). Donors had greater risks of developing detectable highly sensitive troponin T (odds ratio, 16.2 [95% confidence interval, 2.6-100.1]; P<0.01) and microalbuminuria (odds ratio, 3.8 [95% confidence interval, 1.1-12.8]; P=0.04). Serum uric acid, parathyroid hormone, fibroblast growth factor-23, and high-sensitivity C-reactive protein all increased significantly. There were no changes in ambulatory blood pressure. Change in GFR was independently associated with change in left ventricular mass (R(2)=0.28; P=0.01). These findings suggest that reduced GFR should be regarded as an independent causative cardiovascular risk factor. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01028703.

Myocardial strain measurement with feature-tracking cardiovascular magnetic resonance: normal values.

AIMS: Myocardial deformation is a key to clinical decision-making. Feature-tracking cardiovascular magnetic resonance (FT-CMR) provides quantification of motion and strain using standard steady-state in free-precession (SSFP) imaging, which is part of a routine CMR left ventricular (LV) study protocol. An accepted definition of a normal range is essential if this technique is to enter the clinical arena. METHODS AND RESULTS: One hundred healthy individuals, with 10 men and women in each of 5 age deciles from 20 to 70 years, without a history of cardiovascular disease, diabetes, renal impairment, or family history of cardiovascular disease, and with a normal stress echocardiogram, underwent FT-CMR assessment of LV myocardial strain and strain rate using SSFP cines.Peak systolic longitudinal strain (Ell) was -21.3 ± 4.8%, peak systolic circumferential strain (Ecc) was -26.1 ± 3.8%, and peak systolic radial strain (Err) was 39.8 ± 8.3%. On Bland-Altman analyses, peak systolic Ecc had the best inter-observer agreement (bias 0.63 ± 1.29% and 95% CI -1.90 to 3.16) and peak systolic Err the least inter-observer agreement (bias 0.13 ± 6.41 and 95% CI -12.44 to 12.71). There was an increase in the magnitude of peak systolic Ecc with advancing age, which was greatest in subjects over the age of 50 years (R(2) = 0.11, P = 0.003). There were significant gender differences (P < 0.001) in peak systolic Ell, with a greater magnitude of deformation in females (-22.7%) than in males (-19.3%). CONCLUSION: Normal values for myocardial strain measurements using FT-CMR are provided. All circumferential and longitudinal based variables had excellent intra- and inter-observer variability.

Feature-tracking cardiovascular magnetic resonance as a novel technique for the assessment of mechanical dyssynchrony.

BACKGROUND: Myocardial tagging using cardiovascular magnetic resonance (CMR) is the gold-standard for the assessment of myocardial mechanics. Feature-tracking cardiovascular magnetic resonance (FT-CMR) has been validated against myocardial tagging. We explore the potential of FT-CMR in the assessment of mechanical dyssynchrony, with reference to patients with cardiomyopathy and healthy controls. METHODS: Healthy controls (n=55, age: 42.9 ± 13 yrs, LVEF: 70 ± 5%, QRS: 88 ± 9 ms) and patients with cardiomyopathy (n=108, age: 64.7 ± 12 yrs, LVEF: 29 ± 6%, QRS: 147 ± 29 ms) underwent FT-CMR for the assessment of the circumferential (CURE) and radial (RURE) uniformity ratio estimate based on myocardial strain (both CURE and RURE: 0 to 1; 1=perfect synchrony) RESULTS: CURE (0.79 ± 0.14 vs. 0.97 ± 0.02) and RURE (0.71 ± 0.14 vs. 0.91 ± 0.04) were lower in patients with cardiomyopathy than in healthy controls (both p<0.0001). CURE (area under the receiver-operator characteristic curve [AUC]: 0.96), RURE (AUC: 0.96) and an average of these (CURE:RUREAVG, AUC: 0.98) had an excellent ability to discriminate between patients with cardiomyopathy and controls (sensitivity 90%; specificity 98% at a cut-off of 0.89). The time taken for semi-automatically tracking myocardial borders was 5.9 ± 1.4 min. CONCLUSION: Dyssynchrony measures derived from FT-CMR, such as CURE and RURE, provide almost absolute discrimination between patients with cardiomyopathy and healthy controls. The rapid acquisition of these measures, which does not require specialized CMR sequences, has potential for the assessment of mechanical dyssynchrony in clinical practice.

Left ventricular midwall fibrosis as a predictor of mortality and morbidity after cardiac resynchronization therapy in patients with nonischemic cardiomyopathy.

OBJECTIVES: The aim of this study was to determine whether left ventricular (LV) midwall fibrosis, detected by midwall hyperenhancement (MWHE) on late gadolinium enhancement cardiovascular magnetic resonance (CMR) imaging, predicts mortality and morbidity in patients with dilated cardiomyopathy (DCM) undergoing cardiac resynchronization therapy (CRT). BACKGROUND: Midwall fibrosis predicts mortality and morbidity in patients with DCM. METHODS: Patients with DCM with (+) or without (-) MWHE (n = 20 and n = 77, respectively) as well as 161 patients with ischemic cardiomyopathy (ICM) undergoing CRT (n = 258) were followed up for a maximum of 8.7 years. RESULTS: Among patients with DCM, +MWHE predicted cardiovascular mortality (hazard ratio [HR]: 18.6; 95% confidence intervals [CI]: 3.51 to 98.5; p = 0.0008), total mortality or hospitalization for major adverse cardiovascular events (HR: 7.57; 95% CI: 2.71 to 21.2; p < 0.0001), and cardiovascular mortality or heart failure hospitalizations (HR: 9.56; 95% CI: 2.72 to 33.6; p = 0.0004), independent of New York Heart Association class, QRS duration, atrial fibrillation, LV volumes, LV ejection fraction, and a CMR-derived measure of dyssynchrony. Among patients with DCM and ICM, the risk of cardiovascular mortality for DCM +MWHE (adjusted HR: 18.5; 95% CI: 3.93 to 87.3; p = 0.0002) was similar to that for ICM (adjusted HR: 21.0; 95% CI: 5.06 to 87.2; p < 0.0001). Both DCM +MWHE and ICM were predictors of pump failure death as well as sudden cardiac death. LV reverse remodeling was observed in DCM -MWHE and in ICM but not in DCM +MWHE. CONCLUSIONS: Midwall fibrosis is an independent predictor of mortality and morbidity in patients with DCM undergoing CRT. The outcome of DCM with midwall fibrosis is similar to that of ICM. This relationship is mediated by both pump failure and sudden cardiac death.

Magnesium hydroxide bulk and colloid-associated 152Eu in an alkaline environment: colloid characterisation and sorption properties in the presence and absence of carbonate.

The distribution of 152Eu between magnesium hydroxide bulk, colloids and solution has been assessed under alkaline conditions, such as those in nuclear fuel storage ponds. The colloidal phase has been characterised by two complementary methods: coupled ultrafiltration-ICP-AES and scanning electron microscopy. The quantity and the size distribution of the colloidal phase is strongly ionic strength-dependent. A decrease of the quantity of colloids, in particular the larger size ranges, has been observed with increasing ionic strength. Small colloids (1 kDa-10 kDa fraction) are predominant at all ionic strengths. The morphology of colloids, observed by field-emission gun scanning electron microscopy, appears to change from hexagonal prismatic (characteristic to the mineral) to spherical (energetically more favourable) as size decreases. The distribution of 152Eu between the solid and liquid/colloidal phases has been investigated at carbonate concentrations ranging from 0 to 10(-2) M by coupled ultrafiltration and gamma-spectrometry. Mg(OH)2 bulk appears to be a very strong sorbent for 152Eu, since complete sorption onto the bulk happens for carbonate concentrations as high as 10(-3) M. Scavenging of 152Eu by Mg(OH)2 colloids is negligible in the presence of Mg(OH)2 bulk. The distribution of 152Eu between liquid and colloidal phases has been investigated in the absence of bulk at various carbonate concentrations. A significant uptake of 152Eu by the colloids in solution has been observed, which decreases with increasing carbonate concentration. 152Eu appears to be mainly associated to the smallest colloids (1 kDa-10 kDa fraction). There is a strong correlation between the sorption properties and the surface area of the colloids.