Prediction of long-term segmental and global functional recovery of hibernating myocardium after revascularisation based on low dose dobutamine and late gadolinium enhancement cardiovascular magnetic resonance

Background

This study sought to evaluate the relation between long-term segmental and global functional outcome after revascularisation in patients with chronic ischaemic left ventricular dysfunction (LVD) and baseline markers of viability: late gadolinium enhancement (LGE) transmurality and contractile reserve (CR).

Methods

Forty-two patients with chronic ischaemic LVD underwent low-dose dobutamine- (LDD) and late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) before surgical or percutaneous revascularisation. Regional and global left ventricular (LV) functions and LGE were repeatedly assessed 6 ± 1 and 35 ± 6 months after revascularisation. In total, 319 at baseline dysfunctional and successfully revascularised segments were available for statistical analysis.

Results

The likelihood of long-term functional improvement was directly related to the presence of CR and inversely related to both the LGE and the degree of contractile dysfunction at baseline. The time course of functional improvement was protracted, with significantly more delay in segments with more extensive LGE (p = 0.005) and more severe contractile dysfunction at baseline (p = 0.002). The presence of CR was the predictor of earlier functional improvement (p < 0.0001). Using a definition of viable segment as a segment without any LGE or with any LGE and producing CR during LDD stimulation, ≥55% of viable segments from all dysfunctional and revascularised segments in a patient was the only independent predictor of significant improvement (≥5%) in the left ventricular ejection fraction (LVEF) after revascularisation, with a 72% sensitivity and an 80% specificity (AUC 0.76, p = 0.014). Reverse LV remodelling was observed in patients who had a significant amount of viable myocardium successfully revascularised.

Conclusions

In patients with chronic ischaemic LVD, improvement of dysfunctional but viable myocardium can be considerably delayed. Both the likelihood and the time course of functional improvement are related to the LGE, CR and the degree of contractile dysfunction at baseline. At 35 ± 6 months after revascularisation, patients with ≥55% of viable segments from all dysfunctional and revascularised segments significantly improve LVEF and experience reverse LV remodelling. A combination of LDD–CMR and LGE–CMR is a simple and powerful tool for identifying which patients with impaired LV function will benefit from revascularisation.     

Prediction of global left ventricular functional recovery in patients with heart failure undergoing surgical revascularisation,based on late gadolinium enhancement Cardiovascular Magnetic Resonance

Background

The new gold standard for myocardial viability assessment is late gadolinium enhancement-cardiovascular magnetic resonance (LGE-CMR); this technique has demonstrated that the transmural extent of scar predicts segmental functional recovery. We now asked how the number of viable and number of viable+normal, segments predicted recovery of global left ventricular (LV) function in patients undergoing CABG. Finally, we examined which segmental transmural threshold of scarring best predicted global LV recovery.

Methods and Results

Fifty patients with reduced LV ejection fraction (EF) referred for CABG were recruited, and 33 included in this analysis. Patients underwent CMR to assess LV function and viability pre-operatively at 6 days and 6 months. Mean LVEF 38% ± 11, which improved to 43% ± 12 after surgery. 21/33 patients improved EF by ≥3% (EF before 38% ± 13, after 47% ± 13), 12/33 did not (EF before 39% ± 6, after 37% ± 8). The only independent predictor for global functional recovery after revascularisation was the number of viable+normal segments: Based on a segmental transmural viability cutoff of <50%, ROC analysis demonstrated ≥10 viable+normal segments predicted ≥3% improvement in LVEF with a sensitivity of 95% and specificity of 75% (AUC = 0.9, p < 0.001). Transmural viability cutoffs of <25 and <75% and a cutoff of ≥4 viable segments were less useful predictors of global LV recovery.

Conclusions

Based on a 50% transmural viability cutoff, patients with ≥10 viable+normal segments improve global LV function post revascularisation, while patients with fewer such segments do not. LGE-CMR is a simple and powerful tool for identifying which patients with impaired LV function will benefit from CABG.

Trial registration

Research Ethics Committee Unique Identifier: NRES:05/Q1603/42. The study is listed on the Current Controlled Trials Registry: ISRCTN41388968.URL: http://www.controlled-trials.com     

End-systolic versus end-diastolic late gadolinium enhanced imaging for the assessment of scar transmurality

Late gadolinium enhancement (LGE) is widely used to precisely localize and determine the extent and transmurality of myocardial scarring. Performing LGE imaging at end-systole may reduce motion artefacts. It is therefore important to know whether end-systolic imaging influences infarct transmurality in patients with ischemic scar. 107 dysfunctional segments were studied in 20 consecutive patients with established coronary artery disease. Patient specific trigger delays were used to obtain end-diastolic and end-systolic LGE images (LGE(ed), LGE(es)). Wall thickness (WT(ed), WT(es)), thickness of the remaining viable rim (RIM(ed), RIM(es)) and end-diastolic scar thickness were measured manually. There was LGE in 84% of all dysfunctional segments with a mean scar of 3.4 ± 2.5 mm. Total wall thickness and the thickness of the remaining viable rim increased from diastole to systole (WT(ed) 7.8 ± 1.9 vs. WT(es) 8.4 ± 2.2; P < 0.001; RIM(ed) 4.4 ± 3.1 vs. RIM(es) 5 ± 3.4; P < 0.001). Transmurality of scar decreased from end-diastole to end-systole (LGE(ed) 46 ± 33% vs. LGE(es) 44 ± 33%; P < 0.001). This was most pronounced in a subgroup of segments (n = 15) with visual scar transmurality between 50 and 75% (LGE(ed) 75 ± 15% vs. LGE(es) 70 ± 16%; P < 0.001). The change in transmurality was inversely correlated with the change of the thickness of the remaining viable rim between diastole and systole (r = -0.7; P < 0.001). Scar transmurality was reduced by up to 12% in the individual patient. Scar transmurality changes due to thickening of the remaining viable rim. Whereas these differences might not impact on clinical decision-making in most patients, there will be an occasional misclassification if cut-off values are used (e.g. scar <50 or >50%) or if exact data is required for research studies.     

Quantitation of the thickness of the non-enhanced myocardial rim predicts recovery of territorial myocardial function in chronic ischemic heart disease: a cardiac magnetic resonance imaging study

Objectives

We sought to determine whether the thickness of the non-contrast-enhanced myocardial rim (RIM) predicts recovery of territorial myocardial function after revascularization in chronic ischemic cardiomyopathy (ICM).

Background

Non-contrast-enhanced dysfunctional myocardium at late gadolinium-enhanced CMR depicts the presence of viable myocardium.

Methods

In 29 patients (65 ± 8 years) with ICM (EF 33 ± 10), ceCMR and cine images were acquired 5 ± 10 days before revascularization. Cine images were repeated after 6 months. Regional wall thickness, wall thickening and RIM were determined in each of 12 segments per short-axis slice (4–8/patient), which were assigned to the respective supplying coronary artery (LAD, LCX and RCA). A threshold for normal wall-thickening was derived from a control group (n = 14; 52 ± 17 years). Functional improvement at follow-up was defined as wall thickening >2 mm.

Results

Of the 1,896 analyzed segments, 655 segments showed severe dysfunction. At follow-up, 307 segments demonstrated functional improvement. The RIM differed between segments with and without improvement (6.6 ± 2.4 mm vs. 2.8 ± 2.0 mm; p < 0.0001). The area under the receiver operator characteristic (ROC) for predicting overall functional recovery was 0.91 (95%, CI 0.88–0.93, p < 0.001). A RIM of 4.0 mm predicted functional recovery after revascularization of the supplying coronary artery with a sensitivity and a specificity of 88 and 82% for the LAD, 96 and 86% for the RCA and 88 and 83% for the LCX, respectively.

Conclusion

RIM may be a useful marker for predicting territorial functional recovery after revascularization in patients with chronic ICM.     

Absence of late gadolinium enhancement on cardiac magnetic resonance imaging in ventricular fibrillation and nonischemic cardiomyopathy

Introduction

Cardiac magnetic resonance (CMR)‐identified late gadolinium enhancement (LGE), representing regional fibrosis, is often used to predict ventricular arrhythmia risk in nonischemic cardiomyopathy (NICM). However, LGE is more closely correlated with sustained monomorphic ventricular tachycardia (SMVT) than ventricular fibrillation (VF). We characterized CMR findings of ventricular LGE in VF survivors.

Methods

We examined consecutively resuscitated VF survivors undergoing contrast‐enhanced 1.5T CMR between 9/2007 and 7/2016. We excluded coronary artery disease, hypertrophic cardiomyopathy, amyloid, sarcoid, arrhythmogenic right ventricular cardiomyopathy, and channelopathy. Preexisting implantable cardioverter‐defibrillator (ICD) was a CMR contraindication. VF patients were divided into three groups: (1) NICM, (2) left ventricular (LV) dilatation with normal LV ejection fraction (LVEF), and (3) normal LV size and LVEF. Two groups of NICM patients with and without SMVT were examined for comparison.

Results

We analyzed 87 VF patients, and found that LGE was seen in 8/22 (36%) with NICM (LVEF 38 ± 11%, LV end‐diastolic volume index [LVEDVI] 134 ± 68 mL/BSA), 11/40 (28%) with LV dilatation and normal LVEF (LVEDVI 103 ± 17 mL/BSA), 4/25 (16%) with normal LV size and LVEF. Incidence of LGE in NICM patients without prior ventricular tachycardia/VF (LVEF 36 ± 12%, LVEDVI 141 ± 46 mL/body surface area [BSA]) was 117/277 and was not lower than those with VF and NICM (42% vs 36%; P = 0.59). By contrast, 22/37 NICM patients with SMVT (LVEF 42 ± 11%, LVEDVI 123 ± 48 mL/BSA) were LGE‐positive (59% NICM‐SMVT vs 36% NICM‐VF; P = 0.04).

Conclusion

Most VF survivors with a diagnosis of NICM did not have LGE on CMR and would not have met primary prevention ICD criteria based on LVEF. Absence of LGE may not portend a benign prognosis in NICM. Novel strategies for determining SCD risk in this cohort are required.

     

Myocardial scarring on cardiovascular magnetic resonance in asymptomatic or minimally symptomatic patients with “pure” apical hypertrophic cardiomyopathy

Background

Late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) enables state-of-the-art in vivo evaluations of myocardial fibrosis. Although LGE patterns have been well described in asymmetrical septal hypertrophy, conflicting results have been reported regarding the characteristics of LGE in apical hypertrophic cardiomyopathy (ApHCM). This study was undertaken to determine 1) the frequency and distribution of LGE and 2) its prognostic implication in ApHCM.

Methods

Forty patients with asymptomatic or minimally symptomatic pure ApHCM (age, 60.2 ± 10.4 years, 31 men) were prospectively enrolled. LGE images were acquired using the inversion recovery segmented spoiled-gradient echo and phase-sensitive inversion recovery sequence, and analyzed using a 17-segment model. Summing the planimetered LGE areas in all short axis slices yielded the total volume of late enhancement, which was subsequently presented as a proportion of total LV myocardium (% LGE).

Results

Mean maximal apical wall thickness was 17.9±2.3mm, and mean left ventricular (LV) ejection fraction was 67.7 ± 8.0%. All but one patient presented with electrocardiographic negative T wave inversion in anterolateral leads, with a mean maximum negative T wave of 7.2 ± 4.7mm. Nine patients (22.5%) had giant negative T waves, defined as the amplitude of ≥10mm, in electrocardiogram. LGE was detected in 130 segments of 30 patients (75.0%), occupying 4.9 ± 5.5% of LV myocardium. LGE was mainly detected at the junction between left and right ventricles in 12 (30%) and at the apex in 28 (70%), although LGE-positive areas were widely distributed, and not limited to the apex. Focal LGE at the non-hypertrophic LV segments was found in some ApHCM patients, even without LGE of hypertrophied apical segments. Over the 2-year follow-up, there was no one achieving the study end-point, defined as all-cause death, sudden cardiac death and hospitalization for heart failure.

Conclusions

LGE was frequently observed not only in the thickened apex of the heart but also in other LV segments, irrespective of the presence or absence of hypertrophy. The simple presence of LGE on CMR was not representative of adverse prognosis in this population.     

Prevalence and distribution of late gadolinium enhancement in a large population of patients with Duchenne muscular dystrophy: effect of age and left ventricular systolic function

Background

Duchenne muscular dystrophy (DMD), an X-linked disorder affects approximately 1 in 5000 males, is universally associated with heart disease. We previously identified myocardial disease by late gadolinium enhancement (LGE) in DMD subjects at various stages of disease, but the true prevalence is unclear. Cardiovascular magnetic resonance (CMR) is well established for both assessment of ventricular function and myocardial fibrosis by LGE. We sought to establish i) prevalence and distribution of LGE in a large DMD population and ii) relationship among LGE, age, LVEF by CMR and current living status.

Methods

Current living status, demographic and CMR data including ventricular volumes, LVEF and LGE from 314 DMD patients undergoing evaluation at a single large tertiary referral center were analyzed.

Results

113 of 314 (36%) of DMD subjects showed LGE positivity with prevalence increasing from 17% of patients <10 years to 34% of those aged 10–15 years and 59% of those >15 years-old. Patients with LVEF ≥55% were LGE positive in 30% of cases; this increased to 84% for LVEF <55%. LGE was more prevalent in the free wall (531/1243, 42.7%) vs. septal segments (30/565, 5.3%). Patients with septal involvement were significantly older and had lower LVEF than those with isolated free wall LGE. Ten percent (11/113) patients who had LGE died 10.8 months after CMR. Only one patient from the LGE negative group died. Patients who died had higher heart rate, larger left ventricular volume and mass, greater number of positive LGE segment and increase incident of septal LGE compared to those who remained alive.

Conclusion

In DMD patients, LGE occurs early, is progressive and increases with both age and decreasing LVEF. Segmentally, the incidence of the number of positive LGE segments increase with age and lower LVEF. Older patients and those who died during the study period had more septal LGE involvement. The current studies suggest that the time course and distribution of LGE-positivity may be an important clinical biomarker to aid in the management of DMD-associated cardiac disease.     

Prevalence and distribution of regional scar in dysfunctional myocardial segments in Duchenne muscular dystrophy

Background

The segmental relationship between cardiovascular magnetic resonance (CMR) peak circumferential strain (Ecc) and myocardial scar has not been well characterized in Duchenne muscular dystrophy (DMD), and it is unknown whether echocardiography accurately measures Ecc in DMD. We assessed segmental Ecc and scar using CMR with myocardial tissue tagging and late gadolinium enhancement (LGE) in patients with DMD, then compared CMR with echocardiographic velocity vector imaging (VVI) for regional Ecc based on independent observer assessments.

Results

Participants enrolled (n = 16; age 8-23) had median left ventricular (LV) ejection fraction of 0.52 (range 0.28-0.69), and 156 basal and mid-cavity myocardial segments from the 13 patients completing the LGE protocol were analyzed for strain and scar. Segmental CMR Ecc in the most negative quartile (quartile 4) ruled out scar in that segment, but scar was present in 46% of segments in the least negative (most dysfunctional) Ecc quartile 1, 33% of Ecc quartile 2 segments, and 15% of Ecc quartile 3 segments. Overall scar prevalence in inferior, inferolateral, and anterolateral segments was eight times higher than in inferoseptal, anteroseptal, and anterior segments (p < 0.001). This increased proportion of scar in lateral versus septal segments was consistent across CMR Ecc quartiles (quartile 1: 76% versus 11%, p = 0.001; quartile 2: 65% versus 9%, p < 0.001; quartile 3: 38% versus 0%, p < 0.001). Echocardiographic analysis could be performed in 12 of 14 patients with CMR exams and had to be limited to mid-cavity slices. Echo segmental Ecc in the most negative quartile made scar by CMR in that segment highly unlikely, but the correlation in segmental Ecc between CMR and echo was limited (r = 0.27; p = 0.02).

Conclusions

The relationship between scar and Ecc in DMD is complex. Among myocardial segments with depressed Ecc, scar prevalence was much higher in inferior, inferolateral, and anterolateral segments, indicating a regionally dependent association between abnormal Ecc and scar, with free wall segments commonly developing dysfunction with scar and septal segments developing dysfunction without scar. Although normal echocardiographic Ecc predicted absence of scar, regional echocardiographic Ecc by VVI has only a limited association with CMR Ecc in DMD.     

Value of black blood T2* cardiovascular magnetic resonance

Background

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare coronary artery anomaly. This study shows the role of cardiovascular magnetic resonance (CMR) in assessing young patients following surgical repair of ALCAPA.

Methods

6 patients, aged 9-21 years, with repaired ALCAPA (2 Tackeuchi method, 4 direct re-implantation) underwent CMR because of clinical suspicion of myocardial ischemia. Imaging used short and long axis cine images (assess ventricular function), late-gadolinium enhancement (LGE) (detect segmental myocardial fibrosis), adenosine stress perfusion (detect reversible ischaemia) and 3D whole-heart imaging (visualize proximal coronary arteries).

Results

The left ventricular (LV) global systolic function was preserved in all patients (mean LV ejection fraction = 62.7% ± 4.23%). The LV volumes were within the normal ranges, (mean indexed LVEDV = 75.4 ± 3.5 ml/m², LVESV = 31.6 ± 9.4 ml/m²). In 1 patient, hypokinesia of the anterior segments was visualized. Five patients showed sub-endocardial LGE involving the basal, antero-lateral wall and the anterior papillary muscle. Three patients had areas of reversible ischemia. In these 3, 3D whole-heart MRA showed that the proximal course of the left coronary artery was occluded (confirmed with cardiac catheterisation).

Conclusions

CMR is a good, non-invasive, radiation-free investigation in the post-surgical evaluation of ALCAPA. In referred patients we show that basal, antero-lateral sub-endocardial myocardial fibrosis is a characteristic finding. Furthermore, stress adenosine CMR perfusion, can identify reversible ischemia in this group, and was indicative of left coronary artery occlusion.     

Prevalence of scarred and dysfunctional myocardium in patients with heart failure of ischaemic origin: A cardiovascular magnetic resonance study

Background

Cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) can provide unique data on the transmural extent of scar/viability. We assessed the prevalence of dysfunctional myocardium, including partial thickness scar, which could contribute to left ventricular contractile dysfunction in patients with heart failure and ischaemic heart disease who denied angina symptoms.

Methods

We invited patients with ischaemic heart disease and a left ventricular ejection fraction < 50% by echocardiography to have LGE CMR. Myocardial contractility and transmural extent of scar were assessed using a 17-segment model.

Results

The median age of the 193 patients enrolled was 70 (interquartile range: 63-76) years and 167 (87%) were men. Of 3281 myocardial segments assessed, 1759 (54%) were dysfunctional, of which 581 (33%) showed no scar, 623 (35%) had scar affecting ≤50% of wall thickness and 555 (32%) had scar affecting > 50% of wall thickness. Of 1522 segments with normal contractile function, only 98 (6%) had evidence of scar on CMR. Overall, 182 (94%) patients had ≥1 and 107 (55%) patients had ≥5 segments with contractile dysfunction that had no scar or ≤50% transmural scar suggesting viability.

Conclusions

In this cohort of patients with left ventricular systolic dysfunction and ischaemic heart disease, about half of all segments had contractile dysfunction but only one third of these had > 50% of the wall thickness affected by scar, suggesting that most dysfunctional segments could improve in response to an appropriate intervention.     

Early detection of subclinical ventricular deterioration in aortic stenosis with cardiovascular magnetic resonance and echocardiography

Background

Severe aortic stenosis (AS) patients with late gadolinium enhancement (LGE) on cardiovascular magnetic resonance (CMR) or left ventricular (LV) systolic dysfunction are known to have worse outcome. We aimed to investigate whether LGE on CMR would be useful in early detection of subclinical LV structural and functional derangements in AS patients.

Methods

118 patients with moderate to severe AS were prospectively enrolled. Echocardiography and CMR images were taken and the patients were divided into groups according to the presence/absence of LGE and of LV systolic dysfunction (LV ejection fraction (EF) <50%). The stiffness of LV was calculated based on Doppler and CMR measurements.

Results

Patients were grouped into either group 1, no LGE and normal LVEF, group 2, LGE but normal LVEF and group 3, LGE with depressed LVEF. There was a significant trend towards increasing LV volumes, worsening of LV diastolic function (E/e’, diastolic elastance), systolic function (end-systolic elastance) and LV hypertrophy between the three groups, which coincided with worsening functional capacity (all p-value < 0.001 for trend). Also, significant differences in the above parameters were noted between group 1 and 2 (E/e’, 14.6 ± 4.3 (mean ± standard deviation) in group 1 vs. 18.2 ± 9.4 in group 2; end-systolic elastance, 3.24 ± 2.31 in group 1 vs. 2.38 ± 1.16 in group 2, all p-value < 0.05). The amount of myocardial fibrosis on CMR correlated with parameters of diastolic (diastolic elastance, Spearman’s ρ = 0.256, p-value = 0.005) and systolic function (end-systolic elastance, Spearman’s ρ = -0.359, p-value < 0.001).

Conclusions

These findings demonstrate the usefulness of CMR for early detection of subclinical LV structural and functional deterioration in AS patients.     

Prospective comparison of novel dark blood late gadolinium enhancement with conventional bright blood imaging for the detection of scar

Background

Conventional bright blood late gadolinium enhancement (bright blood LGE) imaging is a routine cardiovascular magnetic resonance (CMR) technique offering excellent contrast between areas of LGE and normal myocardium. However, contrast between LGE and blood is frequently poor. Dark blood LGE (DB LGE) employs an inversion recovery T2 preparation to suppress the blood pool, thereby increasing the contrast between the endocardium and blood. The objective of this study is to compare the diagnostic utility of a novel DB phase sensitive inversion recovery (PSIR) LGE CMR sequence to standard bright blood PSIR LGE.

Methods

One hundred seventy-two patients referred for clinical CMR were scanned. A full left ventricle short axis stack was performed using both techniques, varying which was performed first in a 1:1 ratio. Two experienced observers analyzed all bright blood LGE and DB LGE stacks, which were randomized and anonymized. A scoring system was devised to quantify the presence and extent of gadolinium enhancement and the confidence with which the diagnosis could be made.

Results

A total of 2752 LV segments were analyzed. There was very good inter-observer correlation for quantifying LGE. DB LGE analysis found 41.5% more segments that exhibited hyperenhancement in comparison to bright blood LGE (248/2752 segments (9.0%) positive for LGE with bright blood; 351/2752 segments (12.8%) positive for LGE with DB; p?<?0.05). DB LGE also allowed observers to be more confident when diagnosing LGE (bright blood LGE high confidence in 154/248 regions (62.1%); DB LGE in 275/324 (84.9%) regions (p?<?0.05)). Eighteen patients with no bright blood LGE were found to have had DB LGE, 15 of whom had no known history of myocardial infarction.

Conclusions

DB LGE significantly increases LGE detection compared to standard bright blood LGE. It also increases observer confidence, particularly for subendocardial LGE, which may have important clinical implications.

     

Impact of milrinone on mitral annular velocity in patients with congestive heart failure

Purpose

The purpose of this study is to assess the impact of milrinone on mitral annular velocity in patients with congestive heart failure.

Method

We studied 27 patients with congestive heart failure. All patients underwent transthoracic echocardiography both before and after administration of milrinone. We measured the early transmitral velocity (E) and the mitral annular early diastolic velocity (Ea). The ratio of E to Ea (E/Ea) was calculated. After the baseline echocardiography, milrinone was administered as a continuous infusion at a rate of 0.25 μg/kg/min. Echocardiographic measurements were repeated 4 h after milrinone was begun.

Results

After administration of milrinone, Ea was significantly increased, while E/Ea was significantly decreased. The population of 27 patients was divided into 20 (74 %) with left ventricular ejection fraction (LVEF) <50 % and seven (26 %) with LVEF ≥50 %. Ea was significantly increased in both groups, while E/Ea was significantly decreased.

Conclusion

Even low-dose milrinone produced an improvement in left ventricular (LV) diastolic function, as evidenced by an increase in Ea, and falls in LV filling pressures, as determined by a decrease in E/Ea, in patients with congestive heart failure throughout a wide range of LV systolic function.     

T1 mapping in children and young adults with hypertrophic cardiomyopathy

To assess the global and segmental left ventricular (LV) native T1 and extracellular volume fraction (ECV) in children and young adults with hypertrophic cardiomyopathy (HCM) compared to a control cohort. The study population included 21 HCM patients (mean 14.1?±?4.6 years) and 21 controls (mean 15.7?±?1.5 years). Native modified Look-Locker inversion recovery sequence was performed before and after contrast injection in 3 short axis planes. Global and segmental LV native T1 and ECV were quantified and compared between HCM patients and controls. Mean native T1 in HCM patients and controls was 1020.4?±?41.2 and 965.6?±?30.2 ms respectively (p?<?0.0001). Hypertrophied myocardium had significantly higher native global T1 and global ECV compared to non-hypertrophied myocardium in HCM (p?<?0.0001,?=?0.14 and 0.048,?=?0.01 respectively). In a subset of patients, ECV was higher in LV segments with LGE compared to no LGE (p?<?0.0001). No significant correlation was identified between global native T1 and ECV and parameters of LV structure and function. Native T1 cut-off of 987 ms provided the highest sensitivity (95?%) and specificity (91?%) to separate HCM patients from controls. Global and segmental native T1 are elevated in HCM patients. LV segments with hypertrophy and/or LGE had higher ECV in a subset of HCM patients. LV native T1 and ECV do not correlate with parameters of LV structure and function. T1 in children and young adults may be used as a non-invasive tool to assess for HCM and related fibrosis.     

Three-dimensional speckle tracking longitudinal strain is related to myocardial fibrosis determined by late-gadolinium enhancement

Three-dimensional (3D) speckle tracking echocardiography (STE) is a reliable clinical tool for accurate measurements of left ventricular (LV) volumes and ejection fraction (EF). In this prospective study, we sought to identify an association between 3DSTE longitudinal strain abnormalities and areas of late gadolinium enhancement (LGE). In 50 patients (52?±?18.5 years old) referred to our hospital for clinically indicated CMR, 3D full-volume trans-thoracic acquisitions on apical views were performed within 1 h of CMR, in order to obtain LV volumes and ejection fraction as well as global and segmental peak systolic longitudinal strain. Relative amount of fibrosis was defined based on LGE CMR with grey-scale threshold of 5 standard deviations above the mean signal intensity of the normal remote myocardium. We found a moderate positive correlation between global longitudinal strain (GLS) by 3DSTE and LGE proportion (r?=?0.465, p?=?0.001). The area under the receiver operating characteristic curve was 0.79. In addition, abnormal GLS could detect LGE-determined myocardial fibrosis with a sensitivity of 84.6%, a specificity of 84.8%, a positive predictive value of 69% and negative predictive value of 93%, considering an optimal GLS cut-off value of ??15.25%. Regarding 3DSTE capacity of localizing segmental LGE involvement, about 70% of LGE-positive segments presented a concomitant longitudinal strain reduction. This prospective study shows that 3DSTE longitudinal deformation is moderately associated with the extent of myocardial fibrosis, with a promising potential role in ruling out prognostically relevant fibrosis as detected by LGE.     

Prognostic value of revascularising viable myocardium in elderly patients with stable coronary artery disease and left ventricular dysfunction: a PET/CT study

Sparse information is available on the role of cardiac viability imaging in elderly patients. We aimed at evaluating the prognostic value of FDG-PET/CT in elderly patients with stable coronary artery disease (CAD) and reduced left ventricular ejection fraction (rLVEF) before revascularisation. Elderly patients (>?65 years old, mean 74?±?7 years old) with CAD and rLVEF were followed after cardiac FDG-PET/CT and stratified according to presence/absence of viable myocardium and subsequent revascularisation. Fatal events of any cause as well as hospitalisations related to acute cardiac conditions were reported as clinical end-points. Predictors of fatal events in patients with viable myocardium (>?1 myocardium segment/20) were analysed. A total of 89 patients were followed (64 viable myocardia; 37 and 27 patients with and without subsequent revascularisation, respectively). The change in LVEF during follow-up (2.1?±?1.6 years) was 3.8?±?6.6% (P?=?0.013) and ??0.75?±?2.6% (P?=?0.170) in patients with and without revascularisation, respectively. Log-rank (P?=?0.037) and multivariate analysis (Wald: 6.305, P?=?0.012) showed viable myocardium to be significantly associated with fatal events if not revascularised. Elderly patients with viable myocardium might potentially benefit from revascularisation procedures as improved left ventricular ejection fraction and survival were observed in our retrospective study as compared to patients in whom a revascularisation procedure was denied. Viable myocardium as detected by cardiac FDG PET/CT was associated with better clinical outcomes in elderly patients when revascularised.     

Comparison of cardiovascular magnetic resonance characteristics and clinical consequences in children and adolescents with isolated left ventricular non-compaction with and without late gadolinium enhancement

Background

Although cardiovascular magnetic resonance (CMR) is showing increasingly diagnostic potential in left ventricular non-compaction (LVNC), relatively little research relevant to CMR is conducted in children with LVNC. This study was performed to characterize and compare CMR features and clinical outcomes in children with LVNC with and without late gadolinium enhancement (LGE).

Methods

A cohort of 40 consecutive children (age, 13.7 ± 3.3 years; 29 boys and 11 girls) with isolated LVNC underwent a baseline CMR scan with subsequent clinical follow-up. Short-axis cine images were used to calculate left ventricular (LV) ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV), myocardial mass, ratio of non-compacted-to-compacted myocardial thickness (NC/C ratio), and number of non-compacted segments. The LGE images were analyzed to assess visually presence and patterns of LGE. The primary end point was a composite of cardiac death and heart transplantation.

Results

The LGE was present in 10 (25 %) children, and 46 (27 %) segments were involved, including 23 non-compacted segments and 23 normal segments. Compared with LGE- cohort, LGE+ cohort had significantly lower LVEF (23.8 ± 10.7 % vs. 42.9 ± 16.7 %, p < 0.001) and greater LVEDV (169.2 ± 65.1 vs. 118.2 ± 48.9 mL/m², p = 0.010), LVESV (131.3 ± 55.5 vs. 73.3 ± 46.7 mL/m², p = 0.002), and sphericity indices (0.75 ± 0.19 vs. 0.60 ± 0.20, p = 0.045). There were no differences in terms of number and distribution of non-compacted segments, NC/C ratio, and myocardial mass index between LGE+ and LGE- cohort. In the LGE+ cohort, adverse events occurred in 6 patients compared to 2 events in the LGE- cohort. Kaplan-Meier analysis showed a significant difference in outcome between LGE+ and LGE- cohort for cardiac death and heart transplantation (p = 0.011).

Conclusions

The LGE was present in up to one-fourth of children with LVNC, and the LGE+ children exhibited a more maladaptive LV remodeling and a higher incidence of cardiovascular death and heart transplantation.     

Extracellular volume fraction in dilated cardiomyopathy patients without obvious late gadolinium enhancement: comparison with healthy control subjects

To evaluate whether the extracellular volume fraction (ECV) measured using cardiac magnetic resonance (CMR) imaging can detect myocardial tissue changes in dilated cardiomyopathy (DCM) without late gadolinium enhancement (LGE). Forty-one DCM patients and 10 healthy volunteers underwent pre- and post-T1 mapping using a modified Look-Locker Inversion recovery sequence, LGE, and cine MRI on a 3-T CMR system. LGE-MR findings were used to divide DCM patients into two groups: Group A had no apparent LGE, and Group B had LGE apparent in at least one segment. The ECV of the left ventricle (LV) myocardium (16 segments) was calculated in the short-axis view as follows: ECV = [(ΔR1 of myocardium/ΔR1 of LV blood pool)] × (1 ? hematocrit), where R1 = 1/T1, ΔR1 = post-contrast R1 ? pre-contrast R1. The LV ejection fraction (LVEF) was obtained from cine MRI images. The mean myocardial ECV in LGE (?) segments in Group A + B was compared to that of controls. The mean myocardial ECV in Group A was compared to that of LGE (?) segments in Group B. The correlation between LV systolic function and the mean myocardial ECV of the whole myocardium was evaluated in all groups. Among the 41 DCM patients, 22 were in Group A, and 19 were in Group B. The mean ECV of DCM patents (n = 41, 568 segments, 30.7 % ± 5.9) was significantly higher (P < 0.001) than that of the control group (n = 10, 157 segments, 25.6 % ± 3.2). The ECV was inversely related to LVEF in Group A (r = ?0.551, P = 0.008), Group B (r = ?0.525, P = 0.021), and Group A + B (r = ?0.550, P < 0.001). The ECV measured by MRI could be a useful parameter in evaluating diffuse myocardial changes in DCM patients.     

Head-to-head comparison of contrast-enhanced cardiovascular magnetic resonance and (201)Thallium single photon emission computed tomography for prediction of reversible left ventricular dysfunction in chronic ischaemic heart disease

Delayed contrast-enhanced cardiovascular magnetic resonance (DE-CMR) allows assessment of reversibility of myocardial dysfunction. Comparative data to other modalities is scarce. Purpose of this study was to compare DE-CMR and (201)Thallium single photon emission computed tomography (SPECT) for prediction of reversible left ventricular (LV) dysfunction in patients with chronic ischaemic heart disease. Fifty-four patients with LV dysfunction (mean ejection fraction (EF) 35?±?8%) scheduled to undergo myocardial revascularization underwent DE-CMR and SPECT. Cine CMR was performed at baseline and at 8?months follow-up for assessment of regional and global myocardial function. Myocardial viability was determined by the segmental extent of delayed enhancement for DE-CMR, and by quantitative analysis of tracer uptake for SPECT, and was correlated to functional recovery after revascularization. After revascularization, 172 (49%) of 350 dysfunctional segments improved at follow-up cine CMR. Sensitivity and specificity for the prediction of functional recovery was 92 and 88%, respectively, for DE-CMR as compared to 86% (P?=?0.4) and 56% (P?=?0.001) for SPECT. Global LV function showed an increase of EF?>?5% in 22 (41%) patients. The DE-CMR derived viability ratio (dysfunctional but viable myocardium) of 0.46 (sensitivity 91%, specificity 91%) was identified as predictor of increase in EF?>?5% (P?=?0.02), whereas the corresponding SPECT parameters were not predictive. DE-CMR compares favorably to SPECT for the prediction of regional and global improvement in LV function in the setting of chronic myocardial ischemia.     

磁共振特征追踪技术定量左心室应变与急性STEMI后微血管阻塞的关系

目的 采用心脏磁共振特征追踪技术(CMR-FT)量化急性ST段抬高型心肌梗死(STEMI)患者急性期左心室心肌应变及心功能改变，探讨其检测心肌梗死伴微血管阻塞(MVO)的可行性。方法 收集78例急性STEMI患者(梗死组)和10名健康志愿者(对照组)的CMR动态电影序列图像及钆对比剂延迟强化成像(LGE)资料。采用CMR-FT分析电影序列图像左心室整体心肌应变[整体峰值径向应变(GPRS)、周向应变(GPCS)及纵向应变(GPLS)]、节段心肌应变[节段峰值径向应变(PRS)、周向应变(PCS)及纵向应变(PLS)]和左心室心功能[左心室射血分数(LVEF)、左心室舒张末期容积指数(LVEDVi)、左心室收缩末期容积指数(LVESVi)及心脏指数(CI)]。根据LGE评估是否存在MVO，将患者分为MVO组(n=50)和无MVO组(n=28)，将其左心室心肌节段分为MVO节段组(n=173)和无MVO节段组(n=1075)。根据左心室节段应变绘制ROC曲线，并计算AUC值。结果 梗死组左心室GPRS、GPCS、GPLS、PRS、PCS及PLS与对照组差异有统计学意义（P均<0.001）；梗死组左心室LVEF、LVEDVi、LVESVi与对照组差异有统计学意义（P均<0.05）；MVO节段组在左心室PRS、PCS、PLS与无MVO节段组差异有统计学意义（P均<0.001）；PRS和PCS取24.65%和-14.05%时检测MVO的敏感性、特异性、AUC分别为89.0%、60.6%、0.816和75.7%、75.9%、0.818。结论 采用CMR-FT测量左心室心肌节段峰值应变可检测急性STEMI患者是否发生MVO，为临床对急性STEMI患者进行早期风险分层管理提供了无创、便捷的新方法。