Robustness of T1 and ECV mapping radiomics features: a between-session evaluation in young athletes

Funding Acknowledgements

Type of funding sources: None.

Introduction

Radiomics of cardiac MRI T1, T2 and extracellular volume (ECV) maps has the potential to add biomarkers that can aid in the detection and diagnosis of myocardial diseases. Recently, the feasibility of CMR mapping based radiomics to classify various myocardial diseases was demonstrated [1-6]. However, reproducibility studies have reported sensitivity of radiomics to acquisition parameters and processing steps involved concluding that only a limited number of features may be reproducible [7-8]. As CMR mapping guidelines recommend to use site-specific normal values [9], radiomics features derived likely also need careful site-specific evaluation to benchmark disease-related feature alterations.

Purpose

We aimed to assess the between-session reproducibility of radiomics features in a longitudinal dataset of MOLLI T1 and ECV maps obtained in young athletes at 1.5T.

Materials and methods

This study included data from 17 healthy subjects (15-20y; informed consent obtained) with data acquired two years apart [10] considered for this purpose as test-retest data since a prior standard analysis showed near identical average T1 (t1: 977±16 ms, t2: 982±20ms) and ECV (t1: 23.4±1.3%, t2: 23.4±1.5%). T1 mapping data was acquired on a 1.5T system (Ingenia, Philips) using MOLLI 5s(3s)3s. After motion correction and T1 and ECV map calculation [11], the left ventricular myocardium was manually delineated by two readers independently (3D Slicer [12]). In total 44 images (short and long axis) were included for each time point. The radiomics analysis resulted in 96 features per image (7 feature families, ‘shape’ excluded; no filters applied; Pyradiomics, [13]). The concordance correlation coefficient (CCC) was calculated to assess reproducibility, and features with CCCs ≥ 0.7 were considered reproducible. A coefficient of variation (CV) below 15% was considered low.

Results

Only a limited number of radiomics features had high CCC (T1: 6/96 ECV 0/96) or a low CV (T1: 32/96, ECV:30/96) in the between-session analysis. The inter-reader evaluation showed that the effect of the delineation on the results was limited. Features that were most robust in the between-session analysis were ‘first order (total)energy’ for T1 maps and ‘glcm_Autocorrelation’ for ECV maps (table 1). These results in young healthy subjects confirm previous test-retest reports [9-10]. Features with low CCC levels or high CV may however still be useful when discriminating between patient with myocardial diseases if the difference is larger than the confidence interval assessed via this reproducibility analysis.

Conclusion

In these healthy subjects, a strong variability in reproducibility of radiomics features of T1 and ECV mapping can be noted. Nonetheless, these variability measures are informative to determine features that are likely most robust when discriminating between health and disease and can be used as a benchmark towards radiomics AI-based diagnostic approaches. Top ranked features for either T1 or ECV

The prevalence and clinical significance of a reduced ventricular ejection fraction in asymptomatic young elite endurance athletes

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Health and Medical Research Council of Australia

Background

Ventricular ejection fraction (EF) is the most widely used parameter to evaluate ventricular systolic function. Endurance athletes presenting with a reduced ventricular EF often raise the question of an underlying dilated or arrhythmogenic cardiomyopathy. The clinical significance of a reduced EF in athletes remains to be elucidated.

Purpose

To investigate the prevalence and clinical significance of a reduced EF in asymptomatic endurance athletes.

Methods

Two hundred eighteen asymptomatic young elite endurance athletes were evaluated at baseline. Cardiac magnetic resonance imaging (CMR) was performed to assess cardiac volumes, left ventricular and right ventricular EF (LVEF and RVEF), mass and fibrosis. Athletes with reduced EF (ATrEF) were defined as those having LVEF<50% and/or RVEF<45%. Ventricular systolic and diastolic function were assessed by trans-thoracic echocardiography. A 12-lead ECG and 24-hour holtermonitoring assessed electrical alterations and arrhythmias. In 145 athletes, LV and RV contractile reserve was evaluated by exercise CMR. Cardiopulmonary testing was performed in all athletes to measure maximal oxygen uptake (VO2max).

Results

Thirty-one ATrEF (14.2%) were compared to 187 athletes with a preserved EF (ATpEF). ATrEF were more frequently males (93 vs 77% male, p=0.033) but did not differ from ATpEF with regard to age (18.8±2.1 vs 18.3±2.1 years, p=0.25). Ten athletes had an isolated reduced LVEF, 10 had an isolated reduced RVEF and 11 had both a reduced LVEF and RVEF. ATrEF had similar end-diastolic volumes and cardiac mass but differed by higher end-systolic volumes.

Peak exercise LVEF and RVEF determined by exercise CMR remained lower in ATrEF (68±3 vs 73±4% and 62±6 vs 69±5%, p<0.001) but contractile reserve was greater (ΔLVEF 18±5 vs 14±4% and ΔRVEF 19±5 vs 15±5%, p<0.01).

A reduced EF was not associated with lower exercise capacity, in fact VO2max was higher in ATrEF than in ATpEF (65±6 vs 62±9mL/kg/min, p=0.020) and the percentage of predicted VO2max by the Wasserman equation were similar (151±14 vs 149±21%, p=0.533).

Fibrosis was present in 3 ATrEF and 18 ATpEF (9.7 vs 9.6%, p=0.993) and was isolated to the RV hinge-points in all but 3 ATpEF who had midmyocardial LV lateral wall fibrosis. LV systolic strain (-17.5±2.0 vs -19±2.1%, p<0.001) was lower in ATrEF whereas RV free wall systolic strain (-24.9±3.7 vs -25.1±3.5%, p=0.776) was similar. Diastolic function was normal in all ATrEF and ATpEF. Pathologic T-wave inversions were present in 2 ATrEF and 13 ATpEF (6.5 vs 7%, p=0.999). Ventricular premature beats (VPB) were infrequent but more prevalent in ATrEF than in ATpEF (2[0-18] vs 1[0-2]/24h, p=0.025; 16.1 vs 2.7% >100/24h, p=0.006).

Conclusion

A reduced ventricular EF is common in asymptomatic young elite endurance athletes, is more frequent in males but is not associated with structural, functional or electrical abnormalities apart from a minor excess in VPB.

Combined assessment of septal scar and septal flash by cardiac magnetic resonance identifies responders to cardiac resynchronization therapy

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): South-Eastern Norway Regional Health Authority. Research grants of the University of Leuven.

Background

Left ventricular (LV) scar, particularly in the lateral wall and septum, reduces response rate to cardiac resynchronization therapy (CRT), whereas a dyssynchronous LV contraction pattern (septal flash) suggests good response. Lateral wall scar abolishes septal flash. Therefore, a combined approach of septal scar and septal flash may characterize the myocardial substrate responsive to CRT. Cardiac magnetic resonance (CMR) may assess both scar and contraction pattern.

Purpose

The present study aimed to determine if combined assessment of septal scar and septal flash by CMR as single image modality identifies responders to CRT.

Methods

We investigated all CRT recipients with available CMR from a prospective, multicenter study (n = 136), with both ischemic and non-ischemic heart failure. Septal scar was assessed by late gadolinium enhancement (LGE) from a stack of short axis slices (n = 128) and septal flash determined visually on ordinary cine sequences (n = 136). CRT response was defined as ≥15% reduction in LV end-systolic volume by echocardiography at 6 months follow-up. We also assessed heart transplantation or death of any cause 39 ± 13 months after device implantation.

Results

In multivariate analysis including percentage septal scar (LGE), septal flash, QRS-duration and QRS-morphology, septal LGE and septal flash were the only independent predictors of CRT response (both p < 0.001). A combined approach of septal LGE and septal flash predicted CRT response with area under the curve 0.86 (95% confidence interval (CI): 0.78-0.94) and long-term survival without heart transplantation with hazard ratio 0.18 (95% CI: 0.05-0.61).

A practical approach to selection of CRT candidates by septal LGE and septal flash is illustrated in the present figure. As shown, absence of septal LGE indicated excellent response rate (93%) to CRT independent of other parameters. When septal LGE was present, however, overall response rate was substantially lower (58%), but presence or absence of septal flash separated responders from non-responders with high accuracy. This sequential approach correctly classified 86% of patients. Importantly, the approach was equally accurate in patients with intermediate QRS duration (130-150ms), where 93% of patients were correctly classified.

Conclusions

Combined assessment of septal LGE and septal flash by CMR as single image modality identifies CRT responders with high accuracy and predicts long-term survival. Abstract Figure.

Segmental evaluation of right ventricular systolic function in atrial septal defect (ASD) type II patients

Introduction

A left to right (LR) shunt in atrial septal defect (ASD) may cause right heart and pulmonary overfilling, at the expense of the systemic circulation.

Purpose

The study objective was to evaluate the impact of LR shunt on left (LV) and right ventricular (RV) filling, function, and myocardial strain by using cardiovascular magnetic resonance imaging (CMR).

Methods

Thirty-five ASD type secundum patients (42±18 y.o.) were compared to a control group (n=40). Cine imaging was used to calculate ventricular volumes and ejection fraction (EF), global longitudinal (GLS) and circumferential (GCS), free wall (FW) and interventricular septal (IVS) longitudinal strain. Phase-contrast imaging was used to calculate pulmonary flow to systemic flow ratio (Qp/Qs).

Results

Qp/Qs was 2.2±0.60 (range 1.3–3.6), which resulted in higher RV end-diastolic volume/BSA (EDVi, 152±42 vs. 82±11 ml/m2), lower LV EDVi (72±17 vs. 83±10 ml/m2), and higher RV/LV EDVi ratio (2.1±0.5 vs. 1±0.1) compared to controls (all p<0.001) [Figure 1]. Patients also presented with higher RV, but lower LV indexed stroke volumes (both p<0.001), and a strong trend toward lower RVEF (p=0.08). They demonstrated significantly lower RV GLS (p=0.03) and longitudinal IVS strain (p<0.001) [Figure 2]. RV FW strain or RV GCS did not differ among study groups. Shunt severity correlated with RV size and stroke volume, right atrial size and pulmonary trunk diameter (all p<0.001). In contrast, no correlation was identified with functional nor strain parameters.

Conclusion

Cardiac remodeling in ASD patients with long-standing LR shunt negatively affects RV systolic performance, which is likely related to longitudinal septal dysfunction.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

Liver magnetic resonance relaxometry can provide useful markers for the assessment of right heart failure in dilated cardiomyopathy

Funding Acknowledgements

Type of funding sources: None.

Introduction

In dilated cardiomyopathy (DCM) patients at risk of developing right heart failure (RHF), early depiction of congestive heart failure (CHF) is pivotal to inform about the hemodynamic status and tailor medical therapy.

Purpose

We hypothesized that increased liver relaxation times measured at routine cardiovascular magnetic resonance (CMR), reflecting passive hepatic congestion, may be a valuable imaging biomarker to depict CHF.

Methods

The study cohort included DCM patients with (n = 48) and without (n = 46) right ventricular dysfunction (RVD), defined as a right ventricular ejection fraction <35%, and >45%, respectively, and a control group (n = 40). Native T1, T2, and extracellular volume (ECV) liver values were measured on routinely acquired cardiac maps.

Results

DCM with RVD patients had higher C-reactive protein, troponin I and NT-pro BNP values, and worse LV functional parameters than DCM without RVD patients (all p < 0.001). T1, T2 and ECV liver values were significantly higher in DCM with, compared to DCM without, RVD patients and also compared to controls [T1: 675 ± 88ms vs. 538 ± 39ms and 540 ± 34ms; T2: 54 ± 8ms vs. 45 ± 5ms and 46 ± 4ms; ECV: 36 ± 7% vs. 29 ± 4% and 30 ± 3%, respectively (all p < 0.001)]. Gamma glutamyltranspeptidase (γGT) correlated moderately but significantly with liver native T1 (r2 =0.34), T2 (r2 =0.27), and ECV (r2 =0.23) (all p < 0.001). Using right atrial pressure (RAP > 5 mmHg), as a surrogate measure of RHF, liver native T1 yielded at ROC analysis the highest AUC (0.906), significantly higher than liver ECV (0.813), γGT (0.806), liver T2 (0.797), total bilirubin (0.737) and alkaline phosphatase (0.561) [Figure 1]. A liver native T1 value of 617 ms showed a sensitivity of 79.5% and a specificity of 91.0% in identifying RHF. Density plots to discriminate between presence and absence of RHF are demonstrated at Figure 2. Excellent intra-/inter-observer agreement was found for assessment of native T1/T2/ECV liver values.

Conclusion

In DCM patients, assessment of liver relaxation times acquired on a CMR exam, may provide valuable information with regard to the presence of RHF.

T1 and ECV mapping texture analysis distinguishing hypertrophic cardiomyopathy from athletes heart better than median values

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ph.D fellowship of the Research Foundation Flanders (FWO). The Master@Heart trial is funded by the FWO.

Introduction

Differentiating intensive training induced hypertrophy from hyperthropic cardiomyopathy (HCM) is important to identify those young athletes at risk of sudden cardiac death. Swoboda and colleagues demonstrated that T1 and ECV mapping can aid such a differentiation between athletic and pathological hypertrophy, particularly in subjects with indeterminate wall thickness (1).

Recently texture analysis (TA) methods of CMR data have demonstrated improved diagnostic accuracy over conventional qualitative analysis in various heart diseases. Only few studies have applied TA to T1 and ECV mapping data (2-4). Here we aimed to demonstrate that a TA approach provides superior capacity to distinguish HCM from athlete’s heart over average native T1 and ECV values.

Purpose

It was our hypothesis that a texture analysis of T1 and ECV mapping images would identify features that could discriminate between a HCM and athlete’s heart with a higher classification accuracy (CA) than average T1 and ECV values.

Methods

This study included data from 97 subjects diagnosed with HCM (acc. to guidelines; 5) and 28 athletes that took part in the Master@Heart trial (an ongoing study assessing the beneficial effects of long-term endurance exercise for the prevention of coronary artery disease, 6).  Long and short axis T1 mapping data was acquired on a 1.5T Philips Ingenia system using MOLLI (seconds scheme). After offline motion correction and T1 and ECV map calculation (7), the left ventricular myocardium was manually delineated (3D Slicer; 8). Texture analysis of the masked images resulted in 194 features (Pyradiomics, standard settings; 9). The dataset was then split (75/25%) for training and testing purposes keeping images from the same subject within the same set. A fast correlation based filter rank was applied to the training data to derive relevant features. A further reduction to only two features was based on the CA of a support vector machine (SVM) learning method (linear kernel; cost 0.9 regression loss epsilon 0.1; leave-one-out). Finally, ROC analysis on the test data was used to determine the diagnostic accuracy for the following predictors: (1) median T1 and ECV (2) two most relevant features (training) (3) combination of (1) and (2) (ROC AUC statistics (10)).

Results

The two most relevant features were the histogram feature ECV energy and the gray level size zone matrix (GLSZM) feature native T1 zone entropy, a measure of heterogeneity in the texture pattern.

A model to distinguish HCM from athletes based on these features outperformed the model using only median T1 and ECV values with both higher sensitivity and specificity (table 1) and a significantly  higher AUC in the ROC analysis (p < 0.05, figure 1). Combining these two features with median values did not improve the CA further. 

Conclusion

Texture analysis of motion-corrected T1 and ECV mapping images out-performs classical analysis based on average values in distinguishing HCM from athlete"s heart.

Adverse remodeling of the subpulmonary left ventricle in patient with systemic right ventricle is associated with clinical outcome

Funding Acknowledgements

Type of funding sources: Other. Main funding source(s): This research received project funding by KU Leuven

Background – Early recognition of adverse remodeling is important since outcome is unfavorable once patients with a systemic right ventricle (sRV) become symptomatic. We aimed assessing prognostic markers linked to short-term clinical evolution in this population. 

Purpose - We aimed assessing short-term clinical evolution and early prognostic markers of cardiac complications in adults with sRV (atrial switch repair for D-transposition of the great arteries (D-TGA) and congenitally corrected transposition of the great arteries (ccTGA)) based on detailed phenotyping. 

Methods– Thirty-three patients with sRV underwent detailed phenotyping including exercise CMR. Adverse outcome was a composite of heart failure episode and tachyarrhythmia. Descriptive statistics and univariate cox regression analyses were performed. 

Results - Thirty-three patients (76% male) with sRV were followed over mean follow-up time of 3 years. Mean age was 40 ± 8 (range 26-57) years at latest follow-up. When compared to baseline, (I) most patients remained in NYHA functional class I (76%),  (II) the degree of severity of the SAVV regurgitation rose and (III) more electrical instability was documented at latest follow-up. Six (18%) of a total of nine events were counted as first cardiovascular events (9% heart failure, 9% arrhythmia). NTproBNP (HR 11.02 (95%CI 1.296-93.662), p= 0.028), oxygen pulse (HR 1.202 (95% CI 1.012-1.428), p = 0.037), left ventricle end diastolic volume index (LVEDVi) in rest (HR 1.046 (95% CI 1.002-1.092), p = 0.041) and during exercise (HR 1.035 (95% CI 1.002-1.069), p = 0.038), stroke volume index (SVi) of the subpulmonary left ventricle (LV) in rest (HR 1.154 (95% CI 1.005-1.322), p = 0.038) and at peak exercise (HR 1.065 (95% CI 1.007-1.125), p = 0.026) were significantly associated with the first cardiovascular event (Figure 1A and B). 

Conclusion – NTproBNP was by far the best prognostic marker for clinical outcome. Adverse remodelling with increase of LVEDVi and SVi of the subpulmonary LV at rest and during exercise were associated with worse clinical outcome. We theorize that remodeling of the subpulmonary ventricle might be an early sign of a failing sRV circulation (Figure 2).

Late gadolinium enhancement predicts adverse clinical outcome in patients with mitral valve prolapse/mitral annulus disjunction

Funding Acknowledgements

Type of funding sources: None.

OnBehalf

Mitral vAlve prolapse and disjunction by cardiac maGnetIC resonance (MA-GIC) registry

Backgroung

Mitral valve prolapse (MVP) is 2-3% prevalent in the general population with good prognosis. However, some patients develop complex ventricular arrhythmias (CVAs), sudden cardiac death (SCD), or severe mitral regurgitation (MR). Previous studies suggested that bi-leaflet involvement, mitral annulus disjunction (MAD), and myocardial fibrosis (MF) are associated with adverse outcome. Notwithstanding, these findings were limited to autopsic series or single-centre studies involving highly selected patients. Moreover, MF has been scantly investigated as predictor of clinical outcome.

Purpose

To investigate the prognostic significance of MF in an international multicentre study of MVP patients studied by cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE). 

Methods

From October 2007 to June 2020 patients undergoing LGE-CMR were screened in 14 European centres. Inclusion criteria were: i) age > 18 years; ii) full clinical history and cardiac rhythm monitoring at baseline; iii) MVP (leaflet displacement ≥ 2 mm beyond the annulus). Exclusion criteria were: i) ischemic heart disease; ii) primary cardiomyopathy; iii) inflammatory heart disease; iv) congenital heart diseases; v) moderate-to-severe valvular heart disease. CVAs at the study outset was defined as one of the following: i) ventricular ectopic beats >10000/24h; ii) ≥ 1 episode of non-sustained ventricular tachycardia (VT); iii) sustained VT; iv) aborted SCD. Primary end-point was a composite of SCD, unexplained syncope, and mitral valve repair/replacement. Secondary end-point was a composite of SCD and unexplained syncope. 

Results

Four-hundred-fifty-eight MVP patients were eventually included (46 ± 16 years old, 51% males) of whom 68% had MAD. LGE was detected in 103 (22%) of subjects with mid-wall pattern (46%) in left ventricular (LV) lateral wall (66%) as the most prevalent feature. At baseline, 37% of LGE-positive patients vs. 18% of LGE-negative individuals had CVAs (P < 0.001). SVT and/or aborted SCD were more prevalent in LGE-positive than in LGE-negative patients (9% vs 2%, P < 0.001). By multivariable Cox-regression analysis, LGE presence or extent were strong independent predictors of the primary (HR = 4.02, P = 0.003 and HR = 4.76 per 10% increase, P = 0.032, respectively) and secondary (HR = 5.39, P = 0.008 and HR = 8.78 per 10% increase, P = 0.012, respectively) endpoints after correction for major confounders including LV volumes, left atrial size and MAD presence.

Conlusion

Myocardial fibrosis by LGE is the strongest independent predictor of clinical outcome in MVP. In contrast, MAD per se does not harbinger worse prognosis.

Left ventricular remodeling in mitral valve prolapse patients: implications of apical papillary muscle implantation

Funding Acknowledgements

Type of funding sources: None.

BACKGROUND

Mitral valve prolapse (MVP) causes left ventricle (LV) remodeling even in the absence of significant mitral regurgitation.

PURPOSE

We sought to evaluate whether apical implantation of the papillary muscle (PM) has an influence on the pattern and severity of MVP-related LV remodeling.

METHODS

All MVP patients who underwent Cardiovascular Magnetic Resonance at our institution between December 2008 and December 2019 were included, thoroughly reviewed and grouped according to apical/non-apical PM implantation.

RESULTS

Apical PM implantation was found in 53/92 patients (58%) and associated with mitral leaflet thickening (p < 0.01) and a trend toward higher prevalence of mitral annular disjunction (p = 0.05). Whereas there were no differences between groups concerning ventricular volumes and ejection fraction, mitral valve prolapse location or severity of mitral valve insufficiency, patients with apical PM implantation showed more lateral wall remodeling with mid lateral wall thinning (2.1 [1.8-2.5]mm vs. 4.0 [3.5-5.0]mm, p < 0.01), increased LV eccentricity and a lower Global Circumferential Strain at this level (15 ± 3% vs. 20 ± 3%, p < 0.01). In long-axis direction, increased end-diastolic mid lateral wall angulation was found (i.e., angle <155° measured in the thinnest point of the mid lateral wall in 4-chamber view) with a higher angle variation during systole (25 ± 11° vs. 17 ± 8° p < 0.01). Remarkably, PM fibrosis was significantly more frequent in patients with apical PM implantation (i.e., 66% vs. 28%, p < 0.01). Importantly, PM fibrosis was observed in the apically implanted PM in the vast majority of cases (86%), showing a strong association between PM fibrosis and its apical implantation. Finally, a higher burden of premature ventricular complexes (>5%) and non-sustained ventricular tachyarrhythmias was found in patients with apical PM implantation: 53% vs. 25% (p = 0.04) and 38% vs. 18% (p = 0.04), respectively.

CONCLUSIONS

Apical PM implantation is part of the phenotypic spectrum of MVP, significantly impacts LV remodeling and potentially may be related to increased ventricular arrhythmogenicity.

Can shear wave imaging distinguish between diffuse interstitial and replacement myocardial fibrosis?

Funding Acknowledgements

Type of funding sources: None.

Background

  Diffuse interstitial or myocardial replacement fibrosis are common features of a large variety of cardiomyopathies. These alterations contribute to functional changes, particularly to an increased myocardial stiffness (MS). Histological examination is the gold standard for myocardial fibrosis quantification, however, it requires endomyocardial biopsy which is invasive and not without risks. Cardiac magnetic resonance (CMR) can characterize the extent of both diffuse and replacement fibrosis and may have prognostic value in various cardiomyopathies. Echocardiographic shear wave (SW) elastography is an emerging approach for measuring MS in vivo. SWs occur after mechanical excitation of the myocardium, e.g. after mitral valve closure (MVC), and their propagation velocity is directly related to MS, thus providing an opportunity to assess stiffness at end-diastole.

Purpose

The aim was to investigate if velocities of natural SW can distinguish between interstitial and replacement fibrosis. 

Methods

We prospectively enrolled 47 patients (22 patients after heart transplant [54.2 ± 15.8 years, 82.6% male] and 25 patients with established hypertrophic cardiomyopathy [54.0 ± 13.5 years, 80.0% male]) undergoing CMR during their check-up. We performed SW elastography in parasternal long axis views of the LV using a fully programmable experimental scanner (HD-PULSE) equipped with a clinical phased array transducer (Samsung Medison P2-5AC) at 1100 ± 250 frames per second. Tissue acceleration maps were extracted from an anatomical M-mode line along the midline of the LV septum. The SW propagation velocity at MVC was measured as the slope in the M-mode image. All patients underwent T1 mapping as well as late gadolinium enhancement (LGE) cardiac magnetic resonance at 1.5 T to assess the presence of diffuse or replacement fibrosis (Figure A). Therefore, patients were divided in three groups: no fibrosis, diffuse fibrosis and replacement fibrosis.

Results

Mechanical SW’s were observed in 46 subjects starting immediately after MVC and propagating from the LV base to the apex. SW propagation velocity at MVC correlated well with native myocardial T1 values (r = 0.65, p < 0.0001) and differed significantly among groups (p < 0.0001), with a significant post-test between any pair of groups (Figure B). SW velocities below a cut-off of 6.01 m/s showed the highest accuracy to identify patients without any type of fibrosis (sensitivity 88 %, specificity 89%, area under the curve = 0.93) (Figure C). A cut-off of 8.11 m/s could distinguish replacement fibrosis from diffuse fibrosis with a sensitivity and specificity of 59% and 92 %, respectively (area under the curve = 0.80) (Figure D).

Conclusions

  Shear wave velocities after mitral valve closure can distinguish between normal and pathological myocardium and can detect differences between diffuse and replacement fibrosis.

Abstract Figure.

Localizing myocardial scar on echocardiography. How good does it work in the presence of conduction delays?

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Research Foundation - Flanders (FWO)

Introduction

Myocardial scar detection with echocardiography in patients with ischemic heart disease typically relies on semi-quantitative evaluation of regional systolic wall thickening. In patients scheduled for cardiac resynchronization therapy (CRT) however, such echo scar estimation is complicated by the presence of dyssynchronous contraction and differential regional remodelling. Visual assessment of myocardial shortening during systole may be an alternative approach. We tested this against cardiac magnetic resonance (CMR) with late gadolinium enhancement (LGE) in patients without and with conduction delay.

Methods

122 patients with ischemic heart disease were included (n = 58 without, and n = 64 with conduction delay). Scar burden of the LV was determined in all patients on a segmental level in both CMR and echo. Reading of echo was blinded for CMR data and vice versa. Myocardial scar was defined as LGE > 50% of transmural thickness. On echo, scar was assessed visually, and defined as thin, echogenic myocardium with no visible shortening during systole. Analysis was performed per segment (18 segment model), and per region (6 walls with basal and mid segment and the apex region consisting of all apical segments). An additional analysis was performed with a tolerance of one adjacent segment in order to account for potential image misalignment between modalities.

Results

2196 segments were available for comparison between echo and CMR. On CMR, 548 of those segments were defined as having >50% transmural scar. In echo, 565 segments were detected as having scar. On a segmental level, no difference was found for the correct assignment of segments by echo as having scar or not between patients without or with conduction delay (AUC 0.79 vs. 0.79; p = 0.968) (Figure, top panels). See Figure for sensitivity and specificity. If one segment tolerance was allowed, segments were correctly assigned with equal accuracy in both patient groups (AUC 0.98 vs. 0.96; p = 0.999) (see Figure; w. tolerance). Agreement on the level of LV regions was comparable. 295 regions had a scar on CMR while 286 regions were identified by echo. Echo correctly identified a scar in the same LV wall or apex as compared to CMR similarly in patients without or with conduction delay (AUC 0.79 vs. 0.77; p = 0.698). If one segment tolerance was allowed, correct identification improved further and was not different between both groups (AUC 0.93 vs. 0.91; p = 0.999). The extent of a scar was slightly underestimated (9%) by echocardiography in comparison to CMR in patients without, and slightly overestimated (3%) in patients with conduction delays.

Conclusions

Scars can be localized on echocardiography with good agreement to CMR-LGE as gold standard. The match between echo and CMR was similar for patients with and without conduction delay. Our findings demonstrate that echo can provide a valid impression of localization and extent of myocardial scar, even in the presence of conduction delays.

Abstract Figure.

Vendor-independent software shows limited variability in speckle tracking strain measurements on images of different vendors

Funding Acknowledgements

Type of funding sources: None.

Background

Vendors use proprietary speckle tracking software algorithms for echocardiographic strain measurements, which results in high inter-vendor variability. Little is known about potential advantages or disadvantages of using vendor-independent software in clinical practice.

Purpose

We therefore investigated the reproducibility, accuracy, and ability to identify scar of strain measurements on images from different vendors by using a vendor-independent software.

Methods

A vendor-independent software (TomTec Image Arena) was used to analyze datasets of 63 patients which were obtained on four ultrasound machines from different vendors (GE, Philips, Siemens, Toshiba). We measured the tracking feasibility, inter-vendor bias, the relative and absolute test-re-test variability of strain measurements and their ability to detect scar. Cardiac magnetic resonance delayed enhancement images were used as the reference standard of scar definition.

Results

Tracking feasibility differed depending on the image source (p < 0.05). Variability of global longitudinal strain (GLS) (Figure 1A) was similar (ANOVA p = 0.124) among the images of different vendors whereas variability of segmental longitudinal strain (SLS) (Figure 1B) showed modest difference (ANOVA- peak systolic strain (PS); p = 0.077, end-systolic strain (ES); p = 0.171, post-systolic strain (PSS); p = 0.020). Relative test-re-test variability of GLS showed no differences (ANOVA p = 0.360). Absolute test-re-test errors of SLS measurements showed modest differences among images of different vendors (ANOVA- PS; p = 0.018, ES; p = 0.001, PSS; p = 0.090). No relevant difference in scar detection capability was observed (Figure 1C).

Conclusions

Vendor independent software leads to low bias among strain measurements on images from different vendors. Likewise, measurement variability and the ability to identify scar becomes similar. Our findings suggest that a vendor independent speckle tracking software could help to overcome inter-vendor bias. To which extend such measurements would be more accurate compared to vendor specific software remains to be determined.

Abstract Figure 1

Septal scar predicts non-response to cardiac resynchronization therapy

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): South-Eastern Norway Regional Health Authority Norwegian Health Association

Background

Scar in the left ventricular (LV) posterolateral wall is associated with poor response to cardiac resynchronization therapy (CRT). The impact of septal scar, however, has been less thoroughly investigated. As recovery of septal function seems to be an important effect of CRT, we hypothesized that CRT response depends on septal viability.

Aim

The aim of the present study was to investigate the association between septal scar and volumetric response to CRT, and to compare the impact of scar located in septum to scar located in the posterolateral wall.

Methods

128 patients with symptomatic heart failure undergoing CRT implantation based on current guidelines (ejection fraction 30 ± 8%, QRS-width 164 ± 17 ms) were included in the study. Volumes and ejection fraction were measured by echocardiography using the biplane Simpson’s method at baseline and six months follow up. Non-response was defined as less than 15% reduction in end-systolic volume. Scar was assessed by late gadolinium enhancement cardiac magnetic resonance, and reported as percentage scar per regional myocardial volume. Numbers are given in [median ;10-90% percentile].

Results

Scar was present in 62 patients (48%). Scar burden was equal in septum [0% ;0-34%] and the posterolateral wall [0% ;0-36%], p = 0.10. 31 patients (24%) did not respond to CRT. The non-responders had higher scar burden than the responders in both septum [16% ;0-57% vs 0% ;0-23%, p < 0.001] and the posterolateral wall [6% ;0-74% vs 0% ;0-22%, p < 0.001].

In univariate regression analysis both septal and posterolateral scars correlated with non-response to CRT (r = 0.51 and r = 0.33, respectively). However, combined in a multivariate model only septal scar remained a significant marker of non-response (p < 0.001), while posterolateral scar did not (p = 0.23).

Septal scar ≥ 7.1% predicted non-response with a specificity of 81% and a sensitivity of 70% by receiver operating characteristic curve analyses. The area under the curve was 0.79 (95% confidence interval 0.70 – 0.89) (Figure).

Conclusions

Septal scar is more closely associated with volumetric non-response to CRT than posterolateral scar. Future studies should explore the correlation between regional scar burden and different functional parameters, and how they relate to CRT response.

Abstract Figure. Septal scar predicts non-response to CRT

Hinge point fibrosis in athletes is not associated with structural, functional or electrical consequences: a comparison between young and middle-aged elite endurance athletes

Background

The health benefits of extensive endurance training have been debated due to the report of myocardial fibrosis (MF), arrhythmias and temporary post-race cardiac impairment in middle-aged and veteran athletes. The extent of these changes is unknown in elite young athletes.

Purpose

To assess the prevalence of MF and its structural, functional and electrical impact in highly trained young endurance athletes (YA, 15–23 years) as compared to middle-aged athletes (MA, 30–50 years). We hypothesised that MF would be more frequent in MA and associated with more structural, functional and electrical abnormalities.

Methods

We prospectively assessed 197 YA and 34 MA. All had ECG, maximal oxygen consumption (VO2max) testing, cardiac magnetic resonance imaging (CMR), echocardiography and 24h-holter. Indexed left ventricular and right ventricular end diastolic volume (LVEDVi, RVEDVi), ejection fraction (LVEF, RVEF), left ventricular mass (LVMi), and MF defined as delayed gadolinium enhancement were assessed by CMR. LV and RV free wall strain (LVSL, RVfwSL) were assessed by 2D speckle tracking echocardiography. Ventricular premature beats (VPB) and non-sustained ventricular tachycardia (nsVT) were assessed by 24h-holter.

Results

YA and MA (18±2 vs 38±5 years [p<0.01]; 78% vs 80% male [p=0.99]) with an elite level of fitness (VO2max 61±8 vs 54±10 mL/min/kg [p<0.01]; % predicted VO2max 150±20 vs 158±30 [p=0.02]) had a large variance in LV and RV remodelling (Figure 1). MF was seen in 28 athletes (12.5%) and more prevalent in MA than in YA (23.5 vs 10.5%, p=0.048). MF was limited to the hinge points in all 8 MA with MF and 17 YA. 3 YA had LV lateral wall subepicardial MF. 27 of 187 (14.4%) male athletes had MF compared to 1 of 50 (2%) female athletes (p=0.01).

MF+ MA(A) and YA(B) as well as MF− MA(C) and YA(D) had similar structural remodelling (LVEDVi 110±14 vs 118±14 vs 113±19 vs 110±16 mL/m2; RVEDVi 120±14 vs 128±17 vs 117±19 vs 125±23mL/m2; LVMi 77±11 vs 83±14 vs 81±14 vs 77±15g/m2, p>0.05). LVEF, LVSL and RVSL were similar (59±3 vs 58±5 vs 61±6 vs 58±6%; −18.8±2 vs −18.8±2 vs −19.8±2 vs −19.3±2%; −26.3±2.4 vs −24.4±2.4; −26.3±3 vs −25.8±3.5% respectively, p>0.05). LVEF <50% was seen in 19 (8.2%) athletes (0 [0%] vs [5%] 1 vs 1 [3.8%] vs 17 [9.6%]; p=0.51). RVEF was higher in D compared to C without further differences between groups (54±4 vs 54±6 vs 53±6 vs 57±5, p=0.005). RVEF<45% was seen 21 (9.1%) athletes (0 [0%] vs 1 [5%] vs 0 [0%] vs 20 [11.3%]; p=0.14). Abnormal T-wave inversion was similar (12.5 vs 5 vs 7.4 vs 6.2%, p=0.93) as was the prevalence of >100VPB/24h (12.5 vs 5 vs 11.1 vs 5.1%, p=0.42). 2 athletes had nsVT, both in D. All had similar exercise capacity (% predicted VO2max 157±26 vs 152±15 vs 147±24 vs 158±32%; p=0.11).

Conclusion

Hinge-point fibrosis was more prevalent in MA, possibly due to repeated hemodynamic stress during exercise, but is not associated with structural, functional or electrical consequences.

Figure 1. Cardiac remodelling in elite athletes

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Fonds voor Wetenschappelijk Onderzoek (FWO)

Shear wave elastography by high frame rate echocardiography can detect diffuse myocardial fibrosis after heart transplantation

Background

Myocardial fibrosis is fundamental in the development of cardiac failure, regardless of ethiology. In both animal models and humans it has been shown that diffuse myocardial fibrosis (DMF) contributes to functional impairment, especially to increased passive myocardial stiffness, which is an important pathophysiological determinant of left ventricular diastolic dysfunction. Histological examination is the gold standard for myocardial fibrosis quantification, however, it requires endomyocardial biopsies which are invasive and not without risk. Echocardiographic shear wave (SW) elastography, based on high frame rate imaging, is an emerging approach for measuring myocardial stiffness in vivo. Natural SWs occur after mechanical excitation of the myocardium, e.g. after mitral valve closure (MVC) and their propagation velocity is directly related to myocardial stiffness, thus providing an opportunity to assess myocardial stiffness at end-diastole.

Purpose

The aim was to investigate if propagation velocities of natural SWs can be used to detect diffuse myocardial fibrosis in a cohort of heart transplant recipients.

Methods

We prospectively enrolled 22 patients (10.3±6.3 years after HTx) that underwent CMR during their annual check-up. We performed SW elastography in parasternal long axis views of the left ventricle using a fully programmable experimental scanner (HD-PULSE) equipped with a clinical phased array transducer (Samsung Medison P2–5AC) at 1100±250 frames per second. The SW propagation velocities at MVC were measured in the basal LV septum. Native T1 and extracellular volume (ECV) were measured at the same segment to evaluate DMF. A cut-off value for native T1 of 1040 ms and for ECV of 29% was used to define DMF in our cohort.

Results

We found good correlations between SW velocities and both myocardial T1 (r=0.80, p<0.0001, Figure A) and ECV (r=0.64, p=0.003, Figure B) measured with CMR. Further, we derived reference thresholds of natural SW velocities to identify DMF in HTx patients. The optimal cut-off value of SW velocity to identify patients with nativT1>1040 ms was 4.84 m/s (AUC 0.81, sensitivity 82%, specificity 82%, Figure C). To identify patients with ECV>0.29 the cut-off value of SW velocity was 4.74 m/s (AUC 0.74, sensitivity 73%, specificity 78%, Figure D).

Conclusions

End-diastolic shear wave propagation velocities, as measure of myocardial stiffness, showed a good correlation with CMR defined diffuse myocardial injury. Values higher than 4.74 m/s could identify diffuse myocardial injury in HTX patients with a good sensitivity and good specificity. These findings thus suggest that shear wave elastography has the potential to become a valuable non-invasive method for the detection of diffuse myocardial fibrosis.

Funding Acknowledgement

Type of funding source: None

Myocardial T1 mapping and extracellular volume quantification as novel biomarkers in risk stratification of patients with systemic sclerosis

AIM

To study the prognostic value of myocardial native T1 and extracellular volume (ECV), measured by cardiovascular magnetic resonance (CMR), in patients with systemic sclerosis (SSc).

MATERIALS AND METHODS

Thirty-three SSc patients (16/33 male, 48.5%) were studied using multiparametric CMR including native T1 mapping with ECV calculation, T2 mapping, and late gadolinium enhancement (LGE). Patients were followed-up for cardiac death, haemodynamically significant arrhythmia, or heart failure. Results were compared with 33 age- and gender-matched healthy controls.

RESULTS

When compared with controls, SSc patients had higher myocardial native T1 (1,058.9±71 versus 989.4±21.4 ms, p<0.001), higher T2 (54.9±5.7 versus 50±2.5 ms, p<0.001), and ECV values (27.9±5.4% versus 24.8±2%, p<0.004). LGE was present in eight patients (24%), two subendocardial, five midwall, and four subepicardial. LGE, native T1, and ECV were significantly associated with adverse events during follow-up in multivariate Cox regression analysis. Kaplan-Meier analysis demonstrated significant divergence of the survival curves based on the presence of elevated native T1 (≥1,069 ms) or ECV (≥31.4%) values.

CONCLUSION

Cardiac involvement is frequent in SSc. Both native T1 mapping and ECV represent novel non-invasive markers of myocardial fibrosis and could be used in the risk stratification of patients with SSc. CMR mapping may provide a novel biomarker for disease monitoring and study of therapies aiming to reduce myocardial fibrosis in SSc.

Review of publications on the possible advantages of a direct cheek incision for accessory parotid gland masses

Lesions of the accessory parotid gland (APG) are rare and surgical management is generally under-discussed. The surgical approach should provide complete resection, while minimising complications and aesthetic complaints. The current study reviews recent publications on the surgical management of APG masses, and discusses the advantages, and limitations of, and our experience with, direct cheek incision. Papers on the surgical management of APG masses published in the last 10 years were systematically searched. Information was obtained regarding the surgical approach, type of excision, and postoperative complications. In the included studies, 253 APG masses were selected for analysis, whereof six were treated with the direct cheek incision. Although no local recurrence or postoperative complications were observed after this, the approach was usually not recommended due to a higher reported risk of recurrence and complications in older papers. More recent studies, however, indicate that the direct cheek incision should be considered as a valuable alternative to standard approaches in selected patients.

556 Shear wave imaging using ultra-high frame rate echocardiography for the assessment of structural changes in cardiac transplant recipients

Background

Cardiac allografts undergo characteristic alterations of the extracellular matrix, including myocardial fibrosis, that contribute to functional changes, particularly diastolic dysfunction due to increased myocardial stiffness(MS). Histological examination is the gold standard for myocardial fibrosis quantification, however, it requires endomyocardial biopsies which are invasive and not without risk. Increased native T1 and extracellular volume(ECV) using CMR T1 mapping have shown good correlation with biopsy evidence of myocardial interstitial fibrosis in heart transplant(HTx) recipients. Echocardiographic shear wave(SW) elastography is an emerging approach for measuring MS in vivo. SWs occur after mechanical excitation of the myocardium, e.g. after mitral(MVC) and aortic valve closure(AVC), and their propagation velocity is directly related to MS, thus providing an opportunity to assess stiffness at end-diastole(ED) and end-systole(ES).

Purpose

The aim was to investigate if natural shear wave velocities increase with the degree of diffuse myocardial fibrosis in HTx recipients.

Methods

We prospectively enrolled 22 HTx patients (8.8 ± 5.9 years post-HTx) that underwent CMR during their annual check-up. We performed SW elastography in parasternal long axis views of the left ventricle(LV) using an experimental scanner (HD-PULSE) equipped with a clinical phased array transducer (Samsung Medison P2-5AC) at 1100 ± 250 frames per second. Tissue acceleration maps were extracted from an anatomical M-mode line along the midline of the LV septum. The SW propagation velocity at MVC and AVC was measured as the slope on the M-mode acceleration map(FigureA). All patients underwent right heart catheterization on the same day for the measurement of pulmonary capillary wedge pressure(PCWP), as surrogate for LV filling pressure. The CMR protocol consisted of standard sequences including native and post-contrast T1 mapping. To evaluate diffuse myocardial fibrosis, native T1 and ECV were measured in the anteroseptal wall over all available short-axis slices.

Results

We found good correlations between SW velocities at ED and both myocardial T1 (r = 0.8,p &lt; 0.001,FigureB) and ECV (r = 0.6,p &lt; 0.05,FigureC) measured with CMR. Similarly, we found significant correlations between SW velocities at ES and T1 (r = 0.7,p &lt; 0.005) and ECV (r = 0.5,p &lt; 0.05), respectively. Furthermore, we observed a significant correlation between SW velocities at ED and PCWP (r = 0.6,p &lt; 0.05).

Conclusions

Both end-diastolic and end-systolic shear wave velocities showed a good correlation with CMR defined myocardial fibrosis in cardiac transplant patients. Shear wave velocities at end-diastole correlated with invasively-determined left ventricular filling pressure, reflecting the impact of the fibrous changes on the left ventricular diastolic function. These results suggest the potential of cardiac shear wave elastography for the assessment of structural changes in cardiac transplant recipients.

Abstract 556 Figure.

1181 A novel insight into pathophysiology of hypertrophic cardiomyopathy using simultaneous three-dimensional volume-strain loops

Funding Acknowledgements

Supported with a scholarship by the Greek State Scholarship Foundation (IKY).

Background

Strain assessment offers a robust evaluation of myocardial mechanics and systolic function, however reporting only peak strain values in hypertrophic cardiomyopathy (HCM) may impose limitations in the conception of its complex remodeling. Therefore, combined plotting of deformation parameters against other indices [e.g. arterial pressure, left ventricular (LV) volume] might offer additional insights into the pathophysiology of the disease.

Purpose

Aim of this study was i) to apply strain-volume loops in HCM based on simultaneous frame-by-frame strain and volume changes’ recordings acquired by means of three-dimensional (3D) speckle tracking imaging and ii) to take advantage of the previous methodology to gain further insights into HCM pathophysiology.

Methods

We included 40 HCM patients (54.1 ± 14.3 years, 82.5% male, maximum wall thickness 19.3 ± 4.8mm) who have consecutively undergone 3D-speckle tracking echocardiography and cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE). Values of 3D strain were plotted vs. volume for each frame to build a strain–volume loop. Peak of radial, longitudinal, and circumferential systolic strain (Rsp, Lsp, and Csp, respectively), systolic slopes of the loops (RsSl, LsSl, CsSl), and strain to end-diastolic volume (EDV) ratio (Rs/V, Ls/V, Cs/V) were computed for the analysis (panel A). Additionally, burden of fibrosis (percentage of LV mass) was defined by LGE extent (&gt;5 standard deviations compared to nulled myocardium) in CMR slices.

Results

All HCM patients had preserved EF (60.5 ± 5,7%), while 16 (40%) had LV outflow tract obstruction (LVOTO &gt; 30 mm Hg at rest). Mean LV mass index was 78.9 ± 14.5 g (evaluated by 3D echocardiography). LGE was observed in 23 patients (57.5%) occupying 5.2 ± 4.5% of LV mass. Concerning strain-volume loops the following values were recorded for radial (Rsp 30.8 ± 9.8%, RsSl 0.4 ± 0.13 and Rs/V 0.25 ± 0.09), longitudinal (Lsp -9.4 ± 3.7%, LsSl 0.12 ± 0.06 and Ls/V 0.08 ± 0.04) and circumferential deformation (Csp -14.2 ± 3.5%, CsSl 0.18 ± 0.05 and Cs/V 0.11 ± 0.03). Among typical HCM characteristics tested (LV mass, LVOTO and LGE), only LV mass presented significant correlations with LsSl (r=-0.41, p &lt; 0.01). Interestingly, HCM patients with smaller LVMI and without LGE presented steeper and narrower (difference between systolic and diastolic strain for the same volume) longitudinal strain-volume loops compared to patients with larger LVMIs and fibrosis (panel B).

Conclusions

Strain-volume loop is an innovative application of 3D deformation imaging in HCM. According to this new non-invasive method, increase of LVMI in HCM is accompanied by less longitudinal contribution to stroke volume, whereas absence of fibrosis and severe hypertrophy is accompanied by better systolic-diastolic coupling.

Abstract 1181 Figure.

P984 A head-to-head comparison between 2D and 3D segmental strain parameters in hypertrophic cardiomyopathy

Funding Acknowledgements

Supported with a scholarship by the Greek State Scholarship Foundation (IKY).

Background

Previous studies have suggested that in normal and ischemic hearts three- (3D) and two-dimensional (2D) strain values present a moderate agreement which is prone to technical considerations. However, the level of agreement between 2D and 3D-strain imaging has never been adequately addressed in hypertrophic hearts, nor has it been validated against a "ground truth". Especially in hypertrophic cardiomyopathy (HCM), the magnitude and eccentricity of hypertrophy set additional challenges in standardization and measurement of regional 3D deformation parameters.

Purpose

Aims of this study were i) to investigate the consistency between 3D and 2D regional deformation parameters in HCM and ii) to test their accuracy in identifying regional fibrosis as this is defined by late gadolinium enhancement (LGE) in cardiac magnetic resonance (CMR).

Methods

We included 40 HCM patients (54.1 ± 14.3 years, 82.5% male, maximum wall thickness 19.3 ± 4.8mm) who have consecutively undergone 2D-,3D-speckle tracking echocardiography and CMR. Segmental circumferential (SCS) and longitudinal (SLS) strain have been calculated from 2D acquisitions and 3D full volume data, where additionally radial (SRS) and area (SAS) strain have been extracted using an 18 segment left ventricle model. Accordingly, segmental fibrosis was defined by LGE in corresponding CMR slices.

Results

Out of 720 segments evaluated, 134 (19.7%) were enhanced and 95(13.2%) thickened (thickness &gt; 12 mm). Two dimensional LS and CS analysis was feasible in 719 (99.9%) and 678 (94.2%) segments respectively, while 686 segments (95.3%) were appropriate for 3D tracking. 3D_SLS values were -7.9 ± 6.8% less negative compared to 2D_SLS values [level of agreement (LOA)(-21.1-5.4%)], while the bias for SCS values was even higher -8.5 ± 8.6 [LOA(-25.4-8.4%)]. Absolute agreement between 2D and 3D deformation imaging modalities was poor to moderate [Intra-class Correlation Coefficient (ICC)= 0.46, 95%CI (0.15-0.68), p &lt; 0.0005 for SLS and ICC = 0.19, 95%CI(0.07-0.38), p &lt; 0.0005 for SCS] (Panel A). Following regression analysis, regional thickness was the only segmental factor to influence the correlation between 3D and 2D_SLS [R2 = 0.504, B = 0.33, 95%CI(0.22-0.44), p &lt; 0.0005)], without, however, being a significant regressor for the other 2D vs 3D correlations. Among deformation indices, 2D_SLS showed the best area under the curve [(AUC)=0.78, 95%CI(0.75-0.81), p &lt; 0.0005] to detect segmental fibrosis identified by CMR LGE, with 3D_SLS, 3D_SAS and 3D_SRS showing similar AUC (0.65) and 3D_SLS presenting the highest specificity [93.1%, 95%CI(90.6-95.1)] (Panel B).

Conclusions

In HCM, 2D and 3D deformation parameters are not interchangeable, showing modest agreement. Thickness and tracking algorithm calculating assumptions seem to induce this inconsistency. Among HCM patients, 2D_SLS remains the most accurate strain parameter to detect regional fibrosis.

Abstract P984 Figure.

P1585 Cardiac magnetic resonance estimated extracellular volume fraction, but not native T1 mapping, detects scar in patients referred for cardiac resynchronization therapy

Funding Acknowledgements

The study was supported by Center for Cardiological Innovation

Background

Myocardial scar burden (focal fibrosis) is associated with poor response to cardiac resynchronization therapy (CRT), and should preferably be detected prior to device implantation. Late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) is considered reference standard for scar detection, but is not available in renal failure. Diffuse fibrosis is assessed by T1 mapping CMR with or without calculation of extracellular volume fraction (ECV). The method is vulnerable to partial volume effects, thus subendocardial tissue is most often not included in mapping analyses. Whether the contrast-free native T1mapping could replace LGE in the preoperative evaluation of patients referred for CRT is unknown.

Purpose

To investigate if native T1 mapping and calculation of ECV can adequately detect scar in patients referred for CRT.

Methods

Scar was quantified as percentage segmental LGE in 45 patients (age 65 ± 10 years, 71% male, QRS-width 165 ± 17ms) referred for CRT. In total 720 segments were analyzed, and LGE≥50% was considered transmural scar. T1-mapping before and after contrast agent injection was performed in all patients. ECV was calculated based on the ratio between tissue T1 relaxation change and blood T1 relaxation change after contrast agent injection, corrected for the haematocrit level. The agreement between native T1/ECV and scar was evaluated with receiver operating characteristic (ROC) curves with calculation of area under the curve (AUC) and 95% confidence interval (CI).

Results

LGE was present in 255 segments, 465 segments were without LGE. Average native T1 in segments with LGE was 1028 ± 88 ms, and 1040 ± 60 ms in segments without LGE (p = 0.16). The corresponding numbers for ECV were 38.7 ± 10.9% and 30.0 ± 4.7%, p &lt; 0.001. Native T1 showed poor agreement to scar independent of scar size (AUC = 0.532, 95% CI 0.485-0.578 for scars of all sizes, and AUC = 0.572, 95% CI 0.495-0.650 for transmural scars). ECV, on the other hand, showed reasonable agreement with scar of all sizes (AUC = 0.777, 95% CI 0.739-0.815), and good agreement with transmural scars (AUC = 0.856, 95% CI 0.811-0.902). (Figure)

Conclusion

The contrast-free CMR technique T1 mapping does not adequately detect scars in patients referred for CRT. Adding post contrast T1 measurements and calculating ECV improves accuracy, especially for transmural scars. Future studies should investigate if diffuse fibrosis could be predictive of CRT response.

Abstract P1585 Figure. Detection of transmural scars

160 Echocardiographic assessment of CRT candidates. Does additional scar evaluation by MRI improve prediction of response?

Background

Myocardial scar presence and extent, has a considerable influence on response to cardiac resynchronization therapy (CRT). Apical rocking (ApRock) and septal flash (SF) are associated with favourable outcome after CRT. Little is known however to which extent visual assessment of mechanical dyssynchrony by ApRock, SF and scar predicts CRT response. We therefore investigated, if additional scar assessment by cardiac magnetic resonance imaging (MRI) adds to the predictive value of the visual evaluation of echocardiographic images in CRT candidates.

Methods

A total of 201 unselected patients referred for CRT, who fulfil the contemporary guidelines for CRT implantation, were enrolled in this prospective multicentre study. Two experienced observers visually assessed echocardiographic images before CRT implantation, focussing on the presence of ApRock, SF and location and extent of scar segments of the left ventricle (LV), resulting in a CRT response prediction (i.e. Integrative Prediction). A third observer provided a consensus reading in case of disagreement. All observers were blinded to all patient information other than the ischaemic aetiology of heart failure. Independent from that, segmental myocardial scar burden was objectified by late gadolinium enhancement (LGE) cardiac MRI (LGE &gt; 50%). CRT response was defined as ≥15% reduction in LV end-systolic volume on echocardiography, one year after device implantation.

Results

Overall, 69 (34%) patients had an ischaemic aetiology of heart failure. Before CRT, ApRock and SF were present in 129 (64%) and 136 (68%) patients, respectively. ApRock and SF alone predicted CRT response with an area under the curve (AUC) of 0.85 (95% CI: 0.79-0.91) and 0.84 (95% CI: 0.77-0.91) (Figure A), while the echocardiographic Integrative Prediction had an AUC of 0.90 (95% CI: 0.84-0.95), with a sensitivity of 93% and a specificity of 87% for the prediction of CRT response (Figure B) (p &lt; 0.05 vs. ApRock and SF alone). When combining information on ApRock, SF and the number of scarred segments on MRI in a statistical model, the AUC was comparable to the echocardiographic Integrative Prediction [0.90 (95% CI: 0.84-0.96)] as was sensitivity and specificity (91% and 83%, respectively, p = N.S. vs. Integrative Prediction) (Figure C).

Conclusions

An integrative visual assessment of LV function has an excellent predictive value for CRT response. Our data show, that the echocardiographic estimation of scar burden is sufficiently accurate and cannot be further improved by an additional MRI scar assessment.

Abstract 160 Figure.

561 Targeting septal work and viability identifies responders to cardiac resynchronization therapy

Funding Acknowledgements

The study was supported by Center for Cardiological Innovation.

Introduction

Septal dysfunction is the dominant mechanism of left ventricular (LV) failure in left bundle branch block (LBBB). We hypothesize that, provided septum is viable, septal function can recover and hence LV function improve after cardiac resynchronization therapy (CRT).

Purpose

To determine if combined assessment of septal function and viability identifies responders to CRT.

Methods

In a prospective multicenter study of 200 unselected patients referred for CRT, we measured myocardial strain by speckle-tracking echocardiography and regional work by pressure-strain analysis before and 7 ± 1 months after CRT. Viability was assessed by late gadolinium enhancement cardiac magnetic resonance imaging (n = 123). CRT response was defined as ≥15% reduction in LV end-systolic volume.

Results

Before CRT, septal work was 258 ± 463 and LV lateral wall work 1469 ± 674 mmHg·% (p &lt; 0.0001). In CRT responders, septal work was restored to 1243 ± 495 mmHg·%, whereas non-responders showed less marked improvement (p &lt; 0.0001). The figure illustrates a typical CRT responder with negative septal work and a large difference between work in the LV lateral wall and septum (panel A). There was no septal scar (panel B) and, after 6 months with CRT, septal work was recovered (panel C). Pressure-strain loops illustrate that CRT converted inefficient septal contractions with substantial negative (wasted) work to positive work throughout systole. For the entire study population, the difference between work in the LV lateral wall and septum predicted CRT response with area under the curve (AUC) 0.75 (95% CI: 0.68-0.83) and was feasible in 98% of patients. Furthermore, septal scar predicted non-response to CRT with AUC 0.76 (95% CI: 0.65-0.86). Combining work difference and septal viability improved AUC for CRT response to 0.85 (95% CI: 0.76-0.94) (figure panel D). The AUC was similar for QRS 120-150 and &gt;150 ms.

Conclusions

The proposed combined approach with assessment of septal work and viability identified CRT responders with high precision.

Abstract 561 Figure.

P4364A direct comparison between 2D and 4D deformation imaging in hypertrophic hearts. An agreement of disagreement

Background

Previous studies have directly compared 2-dimensional (2D) and 4-dimensional (4D) deformation imaging in normal and ischemic hearts suggesting a moderate agreement prone to technical considerations. However, the level of agreement between 2D and 4D-strain imaging has never been adequately addressed in hypertrophic hearts, nor has it been validated against a “ground truth”.

Purpose

We aimed at directly comparing 4D and 2D global and regional deformation parameters and depict which may best reflect underlying segmental fibrosis in hypertrophic cardiomyopathy (HCM), as defined by late gadolinium enhancement (LGE) in cardiac magnetic resonance (CMR).

Methods

We included 40 HCM patients (54.1±14.3 years, 82.5% male, maximum wall thickness 19.3±4.8mm) who have consecutively undergone 2D-,4D-speckle tracking echocardiography and CMR. Global and segmental circumferential (CS) and longitudinal (LS) strain have been calculated from 2D acquisitions and 4D full volume data, where additionally radial (RS) and area (AS) strain have been extracted using an 18 segment left ventricle model. Accordingly, segmental fibrosis was defined by LGE in corresponding CMR slices.

Results

Deformation parameters (2D and 4D, global and regional) presented overall poor to moderate agreement (Figure A+B) with regional 4D_LS and 4D_CS values being constantly less negative compared to 2D derivatives (−7.29±6.94% and −8.53±8.8% accordingly). In regional analysis, 720 segments were evaluated of which 134 (19.7%) were enhanced and 95 of them thickened (68.8%) (thickness>12 mm), with segments presenting both characteristics showing the greatest impairment both in 2D and 4D strain values. Among segmental deformation indices, 2D_SLS showed the best area under the curve [(AUC)=0.78, 95% CI (0.75–0.81), p<0.0005] to detect segmental fibrosis, with 2D_SCS and all 4D deformation indices presenting significantly lower AUC (Figure C).

Conclusions

In HCM, 2D and 4D deformation parameters are not interchangeable, showing modest agreement. Thickness and tracking algorithm calculating assumptions seem to induce this variability. Nevertheless, among HCM patients 2D_SLS remains the best strain parameter for tissue characterization and fibrosis detection.

Acknowledgement/Funding

Supported with a scholarship by the Greek State Scholarship Foundation (IKY).

P5272Right versus Left Ventricular Remodelling after Surgical myectomy for HOCM

Background

Surgical myectomy for (HOCM) results in complex structural and functional changes. “Remodelling” in different cardiac chambers. To date, changes in the Right versus the left Ventricle have not been studied.

Methods

Fourty five patients (mean age = 32±16, 68% males) who underwent extended septal myectomy for LVOTO and Fourty “normal” controls (mean age = 32±12 years, 52% males) were studied by cardiac magnetic resonance imaging (CMR). The patients were studied pre-operatively and 6–18 months post-operatively (median = 9 months). The images were analysed by both commercial and in-house software.

Results

After myectomy. Follow up CMR showed changes in RV mass (21±5 to 23±7) g/m2, volume (60±15 to 66±12) ml/m2 and shape using 3 different methods. RV deformation parameters showed significant changes with circumferential strain (−8±2 to −14±4), filling (38±16 to 62±19) ml/s/m2 and ejection rate (−44±17 to −75±22). Changes in RV were substantially higher than those observed in the LV (Figure. 1, Table. 1). All patients reported significant symptomatic improvement with 31 (78%) patients in NYHA class I and 9 (22%) in class II at follow up. Significant reduction in peak gradient across the LVOT by 75%.

Table 1. Summary of reported parameters related to RV Shape for pre and post operation HOCM patients and Normal Healthy Volunteers LV RV Pre Post Normal P-value Pre Post Normal P-value EDV ml/m2 75±18 81±14 73±10 0.005 60±15 66±12 71±12 0.002 ESV ml/m2 20±9 24±8 26±6 0.008 16±7 19±9 26±7 0.02 SV ml/m2 56±13 57±10 51±13 0.38 44±11 48±10 49±14 0.009 EF 74±7 70±7 65±5 0.001 74±8 72±7 64±6 0.228 Mass g/m2 74±33 62±29 27±8 0.0456 21±5 23±7 18±5 0.2100 PFR ml/m2 173±48 141±48 141±40 <0.0001 38±16 62±19 55±24 <0.0001 PER ml/m2 −179±35 −172±42 −144±42 0.29 −44±17 −75±22 −57±22 <0.0001 Peak Strain −20±3 −20±3 −20±3 0.49 −8±2 −14±4 −12±3 <0.0001

Conclusion

LV septal myectomy is followed by structural and functional remodelling which is more extensive in the right than the left ventricle. The clinical significance of these findings needs further study.

Olmesartan-induced enteropathy treated with budesonide

Olmesartan, an angiotensin receptor blocker, is a widely spread antihypertensive drug. Seronegative villous atrophy of the small intestine due to olmesartan use was first described in 2012. We present a new case of olmesartan-induced enteropathy and compare it to recent literature. This case might suggest a use of budesonide for treatment.

T-Wave Alternans Is Linked to Microvascular Obstruction and to Recurrent Coronary Ischemia After Myocardial Infarction

The purpose of this study is to investigate the relationship between T-wave alternans (TWA), infarct size and microvascular obstruction (MVO) and recurrent cardiac morbidity after ST elevation myocardial infarction (STEMI). One hundred six patients underwent TWA testing 1-12 months and 57 patients underwent cardiac magnetic resonance imaging (MRI) in the first 2-4 days after STEMI. During follow-up (3.5 ± 0.5 years), death (n = 2), ventricular tachycardia (n = 3), supraventricular tachycardia (n = 4), heart failure (n = 3) and recurrent coronary ischemia (n = 25) were observed. After multivariate analysis, positive TWA (HR2.59, CI1.10-6.11, p0.024) and larger MVO (HR1.08, CI1.01-1.16, p0.034) were associated with recurrent angina or ACS. Presence of MVO was correlated with TWA (Spearman rho 0.404, p0.002) and the impairment of LVEF (-0.524, p < 0.001). Patients after STEMI remain at a high risk of symptoms of coronary ischemia. The presence of MVO and TWA 1-12 months after STEMI is related to each other and to recurrent angina or ACS.