Septal Segments Research Articles

Opposite evolution on voltage and thickness from paroxysmal to persistent AF

Abstract Background There is a controversy about correlation between voltage and thickness in the atrial myocardium and their evolution from paroxysmal to persistent atrial fibrillation (AF). Purpose This is an observational study to compare voltage and thickness of different areas on the left atrium in paroxysmal and persistent atrial fibrillation. Methods Twenty-one patients underwent atrial fibrillation ablation. Points with electrical information from an electroanatiomical map in sinus rhythym were acquiered during the ablation procedure covering the whole atrial surface. CT was acquired in all patients before the procedure and endo- and epicardium from the atrium was segmented for the atrial thickness calculation. All the points from the electromecanical map were projected on the thickness map to have both information on the same location. 3D atrium was segmented in 5 areas for the analysis: Lateral, Anterior, Septal, Inferior-Posterior and Superior-Posterior (Figure 1). Voltage and thickness values among different areas and between AF type were compared. Results 11 paroxysmal and 10 persistent AF patients were analyzed acquiring 452±207 points per patient and 1897±750 points per area. There was no linear correlation between voltage and thickness comparing all the patients nor among different areas nor between AF type (R<0.2 in all cases). Regarding paroxysmal AF patients, septum showed significatly lower voltage compared with the other segments, posterior, lateral, anterior and roof (1.3±1.4, 2±1.8, 2±1.6, 1.7±1.5, 2±1.6, P<0.001). Posterior segment showed the highest voltage. The thickness analysis showed the septum segment as thinner segment and lateral as thicker segment (1.3±1.5,1.7±0.8, P<0.001) (Figure 2). Regarding persisten AF patients: septum showed significatly lower voltage compared with the other segments, posterior, lateral, anterior and roof who shows higher voltage (1±0.8*, 1.5±1.2, 1.9±1.7, 1.5±1.4, 2±1.6) (Figure 2). The thickness analysis showed the anterior segment as thinner segment and lateral as the thickest segment (1.6±0.8, 1.9±0.9 (P<0.001), different like on paroxysmal AF population. Comparing voltage and thicknes between paroxysmal and persistent AF, all the segments on persistent population showed lower voltage values, with significant differences on septal, posterior and anterior walls (1±0.8 vs 1.3±1.4, 1.5±1.2 vs 2±1.8, 1.5±1.4 vs 1.7±1.5, P<0.001). On the other hand, all segments on persistent population showed statisticaly signignificant thicker myocardium in camparison with paroxysmal population (Figure 2). Conclusions According to our findings, there is no linear correlation between voltage and thickness. Persistent AF atria show thicker walls but with lower voltages in comparison with paroxysmal AF atria. Funding Acknowledgement Type of funding sources: None.

Asymmetric septal thickening is observed in hypertrophic cardiomyopathy mutation carriers without left ventricular hypertrophy: insights from AI analysis

Abstract Funding Acknowledgements Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Dr Hughes is supported by the British Heart Foundation (grant number FS/17/82/33222). Background Hypertrophic cardiomyopathy (HCM) is a common inherited cardiac disease characterised by left ventricular hypertrophy (LVH), often, with asymmetric septal thickening. Despite the prevalence of inherited mutations present in >50% of cases, there is variable phenotypic expression in those with abnormal sarcomere protein genes. In individuals with abnormal genes but without LVH, we hypothesised that there is subtle asymmetric septal hypertrophy, detectable by the increased precision offered by an artificial intelligence (AI) tool for measuring wall thickness. Purpose We explored the septal-lateral ratio measured by AI in individuals with an identified genotype but no left ventricular hypertrophy as a component of sub-clinical HCM. Methods 43 individuals with identified genotype, but no left ventricular hypertrophy (G+LVH-) and 97 age-, sex- and disease-matched controls underwent CMR. Patients were excluded if they had a maximum wall thickness (MWT) of ≥13mm. A clinically validated AI tool was used to measure the MWT, for each segment in the 16-segment AHA model. The septal-lateral ratio was calculated using the septal segment with the largest MWT and the lateral segment with the largest MWT. Results The mean septal-lateral ratio of the G+LVH- patients was 1.22 (SD 0.22) and the mean septal-lateral ratio of the matched controls was 1.14 (SD 0.15) with a statistically significant mean difference of 0.08 (p=0.01). There was no significant difference between the MWT of the G+LVH- patients at 10.3mm (SD 2.2) and healthy volunteers at 10.1mm (SD 1.8) (p = 0.61). Conclusion G+LVH- patients have a 7% increase in their septal-lateral ratio compared with age-matched controls despite the lack of difference in the MWT. Using increased precision offered by AI, early features of HCM can be observed in patients without overt LVH.

Reduced Circumferential Strain in Athletes with Prior COVID-19.

PurposeTo characterize global and segmental circumferential systolic strain (CS) measured by cardiac MRI in athletes after SARS-CoV-2 infection.Materials and MethodsThis retrospective observational cohort study included 188 soldiers and collegiate athletes referred for cardiac MRI after SARS-CoV-2 infection (C19+) between July 2020 and February 2021 and a control group of 72 soldiers, collegiate, and high school athletes who underwent cardiac MRI from May 2019 to February 2020, prior to the first SARS-CoV-2 case detected in our region (C19-). Global and segmental CS were measured by feature tracking, then compared between each group using unadjusted and multivariable- adjusted models. Acute myocarditis was diagnosed according to the modified Lake Louise criteria and the location of pathologic late gadolinium enhancement (LGE) was ascertained.ResultsAmong the 188 C19+ athletes (median age, 25 years [IQR, 23-30]; 131 men), the majority had mild illness. Global CS significantly differed between C19+ and C19- groups, with a median of -24.0 (IQR -25.8, -21.4) versus. -25.0 (-28.0, -22.4), respectively (p = .009). This difference in CS persisted following adjustment for age, sex, body mass index, heart rate, and systolic blood pressure β coefficient 1.29 [95% CI: 0.20, 2.38], p = .02). In segmental analysis, the basal- and mid- inferoseptal, septal and inferolateral segments were significantly different (p < .05), which had a higher frequency of post-COVID late gadolinium enhancement. The global and segmental differences were similar after exclusion of athletes with myocarditis.ConclusionAmong athletes, SARS-CoV-2 infection was associated with a small but statistically significant reduced CS.

Specific alterations of regional myocardial work in strength-trained athletes using anabolic androgenic steroids compared to athletes with genetic hypertrophic cardiomyopathy

BackgroundStrength-trained athletes using anabolic androgenic steroids (AAS) have left ventricular (LV) hypertrophy and myocardial fibrosis that can lead to sudden cardiac death. A similar feature was described in athletes with hypertrophic cardiomyopathy (HCM), which complicates the diagnosis for clinicians. In this context, we aimed to compare the LV function of the 2 populations by measuring global and regional strain and myocardial work using speckle-tracking imaging. MethodsTwenty-four strength-trained asymptomatic athletes using AAS (AAS-Athletes), 22 athletes diagnosed with HCM (HCM-Athletes), and 20 healthy control athletes (Ctrl-Athletes) underwent a resting echocardiography to assess LV function. We evaluated LV global and regional strains and myocardial work, with an evaluation of the constructive work (CW), wasted work, and work efficiency (WE). ResultsCompared to Ctrl-Athletes, both AAS-Athletes and HCM-Athletes had a thicker interventricular septum, with majored values in HCM-Athletes. LV strain was reduced in AAS-Athletes and even more in HCM-Athletes. Consequently, global WE was significantly diminished in both AAS and HCM-Athletes (93% ± 2% in Ctrl-Athletes, 90% ± 4% in AAS-Athletes, and 90% ± 5% in HCM-Athletes (mean ± SD); p < 0.05). Constructive work and WE regional analysis showed specific alterations, with the basal septal segments preferentially affected in AAS-Athletes, and both septal and apical segments affected in HCM-Athletes. ConclusionThe regional evaluation of myocardial work reported specific alterations of the major LV hypertrophy induced by the regular use of AAS compared to the LV hypertrophy due to HCM. This finding could help clinicians to differentiate between these 2 forms of pathological hypertrophy.

T1 values and extracellular volume fraction in asymptomatic subjects: variations in left ventricular segments and correlation with cardiovascular risk factors

To evaluate variations in pre-contrast (preT1) and post-contrast (postT1) myocardial T1 values and extracellular volume fraction (ECV) according to left ventricular (LV) segments and to find correlations between them and cardiovascular risk factors. The 233 asymptomatic subjects (210 men, 23 women; aged 54.1 ± 6.0 years) underwent cardiac magnetic resonance imaging with preT1 and postT1 mapping on a 1.5-T scanner. T1 values and ECVs were evaluated according to LV segments, age, sex, and estimated glomerular filtration rate (eGFR). Based on the presence of hypertension (HTN) and diabetes mellitus (DM), subjects were subdivided into the control, HTN, DM, and HTN and DM (HTN-DM) groups. T1 values and ECV showed significant differences between septal and lateral segments at the mid-ventricular and basal levels (p ≤ 0.003). In subgroup analysis, the HTN-DM group showed a significantly higher ECV (0.260 ± 0.023) than the control (0.240 ± 0.021, p = 0.011) and HTN (0.241 ± 0.024, p = 0.041) groups. Overall postT1 and ECV of the LV had significant correlation with eGFR (r = 0.19, p = 0.038 for postT1; r = − 0.23, p = 0.011 for ECV). Septal segments show higher preT1 and ECV but lower postT1 than lateral segments at the mid-ventricular and basal levels. ECV is significantly affected by HTN, DM, and eGFR, even in asymptomatic subjects.

Assessing cardiac mechanical dyssynchrony in left bundle branch area pacing and right ventricular septal pacing using myocardial perfusion scintigraphy in the acute phase of pacemaker implantation.

Left bundle branch area pacing (LBBAP) has recently been reported to be a new, clinically feasible and safe physiological pacing strategy. The present study aims to investigate the usefulness of LBBAP in reducing mechanical dyssynchrony compared with right ventricular septal pacing (RVSP). A total of 39 LBBAP patients, 42 RVSP patients, and 93 healthy control participants were retrospectively evaluated. We compared phase analysis- (bandwidth, phase standard deviation [PSD], entropy) and regional wall motion analysis parameters. Wall motion analysis parameters included the time to the end-systolic frame (TES) assessed using single-photon emission computed tomography analysis. The maximum differences between segmental TES (MDTES), the standard deviation of TES (SDTES), and the TES difference between the lateral and septal segments (DTES-LS) were obtained. All phase analysis parameters were significantly smaller in the LBBAP group than in the RVSP group (bandwidth: LBBAP, 74 ± 31° vs. RVSP, 102 ± 59°, p = .009; PSD: LBBAP, 19 ± 6.7° vs. RVSP, 26 ± 15°, p = .007; entropy: LBBAP, 0.57 ± 0.07 vs. RVSP, 0.62 ± 0.11 p = .009). The regional wall motion analysis parameters were also smaller in the LBBAP group than in the RVSP group (MDTES:LBBAP, 17 ± 7.1% vs. RVSP, 25 ± 14%, p = .004; SDTES:LBBAP, 4.5 ± 1.7% vs. RVSP, 6.0 ± 3.5%, p = .015; DTES-LS: LBBAP, 4.1 ± 3.4% vs. RVSP, 7.1 ± 5.4%, p = .004). All phase analysis and wall motion analysis parameters were same in the LBBAP and control groups. LBBAP may reduce mechanical dyssynchrony and achieve greater physiological ventricular activation than RVSP.

Does switching type of mRNA COVID-19 vaccine increases the risk of myocarditis and pericarditis? A case report and literature review

Introduction: Myocarditis and Pericarditis are caused by diverse etiologies, such as infection, toxins, drugs, and vaccines. Myocarditis has been reported previously after smallpox vaccination; however, the incidence was rare. Currently, there are two types of COVID-19 vaccines, mRNA vaccines, and viral vector vaccines. Many cases of myocarditis/Pericarditis after the mRNA COVID-19 vaccine have been reported to the VARES (Vaccine Adverse Event Reporting System). Case Presentation: A 20-year-old male with a history of mild asthma, who previously received two Pfizer covid -19 vaccines, presented to the emergency department with a chief complaint of chest pain two days after receiving a third booster dose of the Moderna vaccine. Troponin and C- Reactive Protein was Elevated, ECG findings revealed acute pericarditis, and MRI showed myocarditis. Echocardiography was normal except for moderate hypokinesis of the septal and inferior left ventricular regional wall segments and trivial pericardial effusion. The patient was admitted for treatment with aspirin, colchicine, metoprolol, and famotidine. His condition was improved, and he was discharged with a follow-up plan.Discussion: So far, most of the cases of Myocarditis/Pericarditis associated with mRNA COVID-19 vaccine were after the second dose; however, not many cases were reported after the booster dose or switching the type of mRNA vaccine. The risk of myocarditis/pericarditis in our patient, with his history of asthma and two doses of Pfizer vaccine, might be increased after switching his booster vaccine to Moderna; nevertheless, the patient still responds well to the treatment without complications. Conclusion: Myocarditis/Pericarditis following receipt of mRNA COVID -19 vaccine is a rare side effect; however, the occurrence of a potentially extremely rare adverse event after an immunization should not lessen the value and the effective benefit of the mRNA COVID-19 vaccine. Further studies are needed to determine the risk of complications following switching between the type of mRNA vaccine.

Cardiac Magnetic Resonance Imaging-Based Screening for Cardiac Sarcoidosis in Patients With Atrioventricular Block Requiring Temporary Pacing.

BackgroundSome myocardial diseases, such as cardiac sarcoidosis, predispose to complete atrioventricular block. The European Society of Cardiology Guidelines on cardiac pacing in 2021 recommend myocardial disease screening in patients with conduction disorder requiring pacemaker with multimodality imaging, including cardiac magnetic resonance (CMR) imaging. The ability of CMR imaging to detect myocardial disease in patients with a temporary pacing wire is not well documented.Methods and ResultsOur myocardial disease screening protocol is based on using an active fixation pacing lead connected to a reusable extracorporeal pacing generator (temporary permanent pacemaker) as a bridge to a permanent pacemaker. From 2011 to 2019, we identified 17 patients from our CMR database who underwent CMR imaging with a temporary permanent pacemaker for atrioventricular block. We analyzed their clinical presentations, CMR data, and pacemaker therapy. All CMRs were performed without adverse events. Pacing leads induced minor artifacts to the septal myocardial segments. The extent of late gadolinium enhancement in CMR imaging was used to screen patients for the presence of myocardial disease. Patients with evidence of late gadolinium enhancement underwent endomyocardial biopsy. If considered clinically indicated, also 18‐F‐fluorodeoxyglucose positron emission tomography and extracardiac tissue biopsy were performed if sarcoidosis was suspected. Eventually, 8 of 17 patients (47.1%) were diagnosed with histologically confirmed granulomatous inflammatory cardiac disease. Importantly, only 1 had a previously diagnosed extracardiac sarcoidosis at the time of presentation with high‐degree atrioventricular block.ConclusionsCMR imaging with temporary permanent pacemaker protocol is an effective and safe early screening tool for myocardial disease in patients presenting with atrioventricular block requiring immediate, continuous pacing for bradycardia.

Cardiac MRI Findings in Male Patients with Acute Myocarditis in the Presence or Absence of COVID-19 Vaccination.

By comparing phenotypic clinical characteristics and cardiovascular magnetic resonance (CMR) findings in 14 patients with COVID-19 mRNA vaccine-associated myocarditis to 14 patients with acute myocarditis from other causes, we found that patients with COVID-19 vaccination- associated acute myocarditis have higher left ventricular ejection fraction, higher left ventricular global circumferential and radial strain, and less involvement of late gadolinium enhancement in the septal segments with less involvement of midmyocardial pattern of late gadolinium enhancement, compared to patients with acute myocarditis from other causes.

High‐Frequency 4D Ultrasound Evaluation of Temporal Changes in Endocardial Surface Strain after Myocardial Infarction

Myocardial infarction (MI) is a leading cause of death and accurate assessment of cardiac function after MI is critical for understanding mechanisms of post‐MI remodeling, recovery and treatment. Most previous studies assessed cardiac function using echocardiographic images of only one section of the heart. Newly developed high‐frequency 4D ultrasound (4DUS) may provide more accurate evaluation of cardiac function, especially after MI when geometry of the heart is abnormal. We investigated left ventricle (LV) endocardial surface peak systolic strain (SPSS) using 4DUS images (VEVO‐3100) before (baseline) and 24‐hr, 72‐hr and 1‐week post‐MI in male Sprague‐Dawley rats (n=5) subjected to left descending coronary artery ligation. Full‐length LV short‐axis ECG‐gated cine loops were acquired with ~11 µm stepwise increments. Compared to baseline, ejection fraction was significantly reduced 24‐hr, 72‐hr and 1‐week post‐MI (65±1 vs. 35±1, 34±3 and 31±2%, respectively). We also observed that SPSS showed different contractility patterns in the base, mid and apical heart regions. Among 17 myocardial segments analyzed, only septal segments were not affected by MI, with the exception of base anterior septal segment which showed reduced SPSS 72‐hr post‐MI (‐4.3 ± 2%) compared to baseline (‐26.5 ± 3%), indicating that the base is more sensitive to MI injury than mid‐LV. Since cardiac global and regional metrics are usually estimated in the mid‐LV, conventional methods may underestimate cardiac function in MI models. Thus, 4DUS with 3D‐strain analysis appears to be a valuable and sensitive tool for improved detection of cardiac disease progression.

T2* assessment of the three coronary artery territories of the left ventricular wall by different monoexponential truncation methods

ObjectivesThis study aimed at evaluating left ventricular myocardial pixel-wise T2* using two truncation methods for different iron deposition T2* ranges and comparison of segmental T2* in different coronary artery territories.Material and methodsBright blood multi-gradient echo data of 30 patients were quantified by pixel-wise monoexponential T2* fitting with its R2 and SNR truncation. T2* was analyzed at different iron classifications. At low iron classification, T2* values were also analyzed by coronary artery territories.ResultsThe right coronary artery has a significantly higher T2* value than the other coronary artery territories. No significant difference was found in classifying severe iron by the two truncation methods in any myocardial region, whereas in moderate iron, it is only apparent at septal segments. The R2 truncation produces a significantly higher T2* value than the SNR method when low iron is indicated.ConclusionClear T2* differentiation between the three coronary territories by the two truncation methods is demonstrated. The two truncation methods can be used interchangeably in classifying severe and moderate iron deposition at the recommended septal region. However, in patients with low iron indication, different results by the two truncation methods can mislead the investigation of early iron level progression.

Molecular markers of cardiac fibrosis after myocardial infarction

Aim. To perform a screening for molecular markers of cardiac fibrosis upon myocardial infarction.Materials and Methods. We carried out echocardiography-guided endomyocardial biopsy of affected and intact interventricular septum segments of 7 patients with anterior myocardial infarction. Fibrotic and adjacent intact cardiac tissue was dissected into 2 equal segments and: 1) homogenized with the further RNA extraction, reverse transcription, and quantitative polymerase chain reaction; 2) fixed in formalin and embedded into paraffin with the further van Gieson staining for the histological verification of cardiac fibrosis.Results. We found that the expression of ACTA2, VIM, CTGF, COL1A1, TGFB1, TGFBR1, AGTR1, CCL2 and TNF genes in fibrotic cardiac tissue was ≥ 3-fold higher as compared with the adjacent intact myocardium reflective of active extracellular matrix production by fibroblast-derived myofibroblasts.Conclusion. We have for the first time shown AGTR1, CCL2, and TNF genes as candidates for post-infarction cardiac fibrosis in addition to ACTA2, VIM, CTGF, COL1A1, TGFB1, and TGFBR1 genes.

Cardiac MRI Features and Prognostic Value in Immune Checkpoint Inhibitor-induced Myocarditis.

Background Cardiac MRI features are not well-defined in immune checkpoint inhibitor (ICI)-induced myocarditis (ICI-M), a severe complication of ICI therapy in patients with cancer. Purpose To analyze the cardiac MRI features of ICI-M and to explore their prognostic value in major adverse cardiovascular events (MACE). Materials and Methods In this retrospective study from May 2017 to January 2020, cardiac MRI findings (including late gadolinium enhancement [LGE], T1 and T2 mapping, and extracellular volume fraction [ECV] z scores) of patients with ICI-M were compared with those of patients with cancer scheduled to receive ICI therapy (pre-ICI group) and patients with viral myocarditis. As a secondary objective, the potential value of cardiac MRI for predicting MACE in patients with ICI-M by using Cox proportional hazards models was explored. Results Thirty-three patients with ICI-M (mean age ± standard deviation, 68 years ± 14; 23 men) were compared with 21 patients scheduled to receive to ICI therapy (mean age, 65 years ± 14; 14 men) and 85 patients with viral myocarditis (mean age, 32 years ± 13; 67 men). Compared with the pre-ICI group, patients with ICI-M showed higher global native T1, ECV, and T2 z scores (0.03 ± 0.85 vs 1.79 ± 1.93 [P < .001]; 1.34 ± 0.57 vs 2.59 ± 1.97 [P = .03]; and -0.76 ± 1.41 vs 0.88 ± 1.96 [P = .002], respectively), and LGE was more frequently observed (27 of 33 patients [82%] vs two of 21 [10%]; P < .001). LGE was less frequent in patients with ICI-M than those with viral myocarditis (27 of 33 patients [82%] vs 85 of 85 [100%]; P < .001) but was more likely to involve the septal segments (16 of 33 patients [48%] vs 25 of 85 [29%]; P < .001) and midwall layer (11 of 33 patients [33%] vs two of 85 [2%]; P < .001). Septal LGE was the only cardiac MRI predictor of MACE at 1 year even after adjustment for peak troponin (adjusted hazard ratio, 2.7 [95% CI: 1.1, 6.7]; P = .03). Conclusion Cardiac MRI features of immune checkpoint inhibitor (ICI)-induced myocarditis (ICI-M) seem to differ from those in patients scheduled to receive ICIs and patients with viral myocarditis. Septal late gadolinium enhancement might be a predictor of major cardiovascular events in patients with ICI-M. Clinical trial registration no. NCT03313544 © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Edelman and Pursnani in this issue.

Characterization of motion patterns by a spatio-temporal saliency descriptor in cardiac cine MRI

Background and objective: Abnormalities of the heart motion reveal the presence of a disease. However, a quantitative interpretation of the motion is still a challenge due to the complex dynamics of the heart. This work proposes a quantitative characterization of regional cardiac motion patterns in cine magnetic resonance imaging (MRI) by a novel spatio-temporal saliency descriptor. Method: The strategy starts by dividing the cardiac sequence into a progression of scales which are in due turn mapped to a feature space of regional orientation changes, mimicking the multi-resolution decomposition of oriented primitive changes of visual systems. These changes are estimated as the difference between a particular time and the rest of the sequence. This decomposition is then temporarily and regionally integrated for a particular orientation and then for the set of different orientations. A final spatio-temporal 4D saliency map is obtained as the summation of the previously integrated information for the available scales. The saliency dispersion of this map was computed in standard cardiac locations as a measure of the regional motion pattern and was applied to discriminate control and hypertrophic cardiomyopathy (HCM) subjects during the diastolic phase. Results: Salient motion patterns were estimated from an experimental set, which consisted of 3D sequences acquired by MRI from 108 subjects (33 control, 35 HCM, 20 dilated cardiomyopathy (DCM), and 20 myocardial infarction (MINF) from heterogeneous datasets). HCM and control subjects were classified by an SVM that learned the salient motion patterns estimated from the presented strategy, by achieving a 94% AUC. In addition, statistical differences (test t-student, p<0.05) were found among groups of disease in the septal and anterior ventricular segments at both the ED and ES, with salient motion characteristics aligned with existing knowledge on the diseases. Conclusions: Regional wall motion abnormality in the apical, anterior, basal, and inferior segments was associated with the saliency dispersion in HCM, DCM, and MINF compared to healthy controls during the systolic and diastolic phases. This saliency analysis may be used to detect subtle changes in heart function.

Multimodality imaging in the evaluation of left ventricle myocardial deformation determined by edema and scar in acute myocarditis

Abstract Funding Acknowledgements Type of funding sources: None. INTRODUCTION acute myocarditis (aMY) is characterized by the presence of edema and myocardial scar detected by cardiovascular magnetic resonance (CMR). Aim of our study is to investigate the diagnostic value of two-dimensional (2D) speckle tracking echocardiography and Cardiovascular Magnetic Resonance (CMR) feature tracking (FT) in detecting edema and myocardial scar in aMY. METHODS all consecutive patients with clinically suspected aMY were enrolled in our study. Inclusion criteria were: 1) new ECG abnormalities 2) myocardial cytolysis markers and 3) absence of angiographically detectable coronary artery disease. Exclusion criteria included poor cine image quality caused by respiratory motion and arrhythmia. All patients underwent transthoracic echocardiography and cardiac function was evaluated by a comprehensive assessment of LV function, including 2D speckle-tracking echocardiography (2D STE). CMR was performed in all patients in a 3T scanner. Extension of edema and myocardial scar were respectively evaluated on T2 mapping and on Late Gadolinium Enhancement sequences considering numbers of segments involved according to 17-segment model (AHA). FT analysis of the left ventricle (LV) was performed using the Tissue Tracking Module to obtain LV strain data. RESULTS 52 patients were included in the study, mean age was 36± 17 years, three patients were female (6%). Mean LVEF was 56,2 ± 7,2 % and mean end diastolic volume index (EDVi) was 62,52 ± 19,02 ml/m2. 10 patients (19,2%) had impaired EF with mean values of 44,6 ± 6,15%. aMY was confirmed in all patients with the presence of myocardial edema and subepicardial late gadolinium enhancement (LGE). Inferior segments were involved in 28 patients (53,8%), lateral segment in 19 patients (36,5%), septal segments in 7 patients (13,5%) and anterior segments in 15 patients (28,8%). 2D STE LV GLS was -16.41± 5,47% while CMR-FT LV GLS was -19,07 ± 4,65%, showing a good agreement between the two methods (r = 0,5; p &amp;lt; 0,001). The univariate analysis showed a significant correlation between 2D STE LV GLS and CMR-FT LV GLS with the extension of myocardial edema assessed by CMR (r= 0,43; p= 0,002 and r = 0.47; p = 0,002 respectively). The univariate analysis did not show a significant correlation between 2D STE LV and the extension of myocardial scar assessed by CMR (r= 0.2; p= 0.155) while a significant correlation was found between CMR-FT LV GLS and myocardial scar (r = 0.4; p = 0.01). CONCLUSIONS in patients with aMY, good correlation was found between CMR-FT and 2D STE in the evaluation of GLS. 2D STE LV GLS and CMR-FT LV GLS proved to have a good correlation with the extension of myocardial edema, while only CMR-FT LV GLS proved to be associated with myocardial scar extension.

Dynamic myocardial response to exercise in children with transposition of the great arteries post arterial switch operation

Abstract Funding Acknowledgements Type of funding sources: None. Background The arterial switch operation (ASO) has improved outcomes for patients with transposition of the great arteries (TGA) however the long-term impact on myocardial function and functional reserve during exercise remains poorly described. The aim of this study was to evaluate left (LV), and right ventricular (RV) myocardial response to exercise in children post ASO using semi-supine cycle ergometry stress echocardiography (SSCE). Methods This is a single-center cross-sectional study. Participants prospectively underwent exercise stress echocardiography using a semi-supine bicycle and a stepwise exercise protocol. Systolic (s’) and diastolic (e’) tissue Doppler velocities, as well as myocardial acceleration during isovolumic contraction (IVA) were measured at rest and during exercise at incremental heart rates (HR) in the basal segments of the RV lateral wall, IVS and LV lateral wall. Systolic and diastolic reserve were evaluated by plotting s’ and e’ against HR while contractile reserve was assessed by plotting IVA values against HR which represents the force-frequency relationship (FFR). Results A total of 40 patients with TGA and 29 controls were included. There were no differences between groups in age (14.6 ± 2.9 vs 14.3 ± 3.1 years, p= 0.75), sex (male= 30/40 vs 20/29 p= 0.58), and resting HR (67 ± 12 vs. 71 ± 12 bpm, p = 0.31). Peak HR was lower in the ASO group (142.2 ±12.4 vs 157 ± 12.3 bpm, p&amp;lt; 0.01). At rest, the ASO group showed lower s’ in the RV and IVS (RV s’: 5.7 ± 1.4 vs. 10.2 ± 2.1 cm/s, p &amp;lt;0.001; IVS s’: 4.2 ± 1.3 vs. 6.2 ± 1.8 cm/s, p&amp;lt; 0.001); lower IVA in the IVS and LV (IVS: 1.01 ± 0.37 vs. 1.23 ± 0.4 m/s2, p= 0.03; LV: 0.86 ± 0.32 vs. 1.1 ± 0.4 m/s2, p =0.02), and reduced e’ in all segments. At peak exercise the ASO group showed reduced s’, e’, and IVA in all segments (table1). When plotted against HR, there was blunting of the s’ slope in RV and septal segments while the LV s’ slope was similar between groups. There were no differences in e’ slope when compared to controls (figure 1). The ASO group showed a blunted IVA response to HR in all measured segments compared to controls. Conclusion(s): Our data demonstrate patients post ASO have reduced RV and LV contractile reserve in response to exercise. The etiology and long-term implications of these abnormalities however remains to be described. Abstract Figure. Doppler velocities at baseline and peak Abstract Figure. Dynamic response to exercise

Right-ventricular involvement in acute myocarditis assessed by cardiac magnetic resonance feature tracking

Abstract Funding Acknowledgements Type of funding sources: None. INTRODUCTION the prevalence of right ventricular (RV) involvement in acute myocarditis (aMY) has been poorly investigated. Actually, RV evaluation may be difficult in echocardiography and scar detection as well as the presence of edema in cardiovascular magnetic resonance (CMR) may be challenging due to small RV wall thickness. We sought to examine the incremental diagnostic value of CMR feature tracking (FT) in RV strain-analysis for patients with aMY. METHODS all consecutive patients with clinically suspected aMY were enrolled in our study. Inclusion criteria were: 1) new ECG abnormalities 2) myocardial cytolysis markers and 3) absence of angiographically detectable coronary artery disease. Exclusion criteria included poor cine image quality caused by respiratory motion and arrhythmias. All patients underwent transthoracic echocardiography (TTE) and CMR within hospitalization on a 3T scan. CMR protocol included current standard Lake Louise criteria (LLC) for myocarditis and T2 weighted images. The definite diagnosis was made when 2 or more Lake Louise criteria were fulfilled. FT analysis of the left ventricle (LV) and RV was performed using the Tissue Tracking Module to obtain LV and RV global longitudinal (RV-GLS) strain data. 20 sex and aged matched individuals who underwent to CMR for suspected cardiac disease, which was not confirmed thereafter, were considered as control population. RESULTS 52 patients were included in the study, mean age was 36 ± 17 years, three patients were female (6%). Mean LV ejection fraction (EF) was 56,2 ± 7,2 and mean end-diastolic volume indexed (EDVi) was 62,52 ± 19,02 ml/mq. 10 patients (19%) had impaired EF with mean values of 44,6 ± 6,1%. All patients have normal RV function evaluated in TTE considering tricuspid annular plane systolic excursion (TAPSE) (22,7 ± 2,4mm). No kinetic abnormalities were reported. All patients underwent CMR within 3 ± 1 days. Normal RV-EF, normal volumes and no RV kinetic abnormalities were reported in all cases also in CMR examination. aMY was confirmed in all patients with the presence of myocardial oedema and subepicardial late gadolinium enhancement (LGE). Inferior segments were involved in 28 patients (54%), lateral segments in 19 patients (37%), septal segments in 7 patients (13%) and anterior segments in 15 patients (29%). RV-GLS was -21,5 ± 5,6% which was not significantly different from control population (-23,01 ± 3,63; p value= 0,201). Globally, 34 patients (65%) had an aMY involving inferior and lateral segments. In this subgroup, RV-GLS was significantly lower compared to other aMY (-19,8 ± 5,7 vs -23,9 ± 4,6 p value = 0,047) and compared to control population (-19,8 ± 5,7 vs -23,01 ± 3,6 p value= 0,032). CONCLUSIONS Despite normal RV function detected in both TTE and CMR, patients with infero-lateral aMY have lower values of RV longitudinal strain. CMR-FT RV strain analysis has proven to be a useful tool in detecting subclinical RV involvement in patients with aMY. Abstract Figure. CMR Right Ventricle GLS

A new approach to artefact detection and its effect on the normal range of segmental strain and strain rate values

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Helse Nord HNF1458-19 Background Definition of normal ranges of myocardial segmental deformation are important in clinical studies and routine echocardiographic practice. It is known that artefacts hamper segmental strain and strain rate (S/SR) analysis. Purpose This study is based on a new approach for artefact detection. We intended to investigate to what degree different types of artefacts and their localization bias the result of measurements and to establish corrected normal ranges for segmental S/SR parameters. Methods The study is based on a collaboration project between the Russian cross-sectional study "Know your heart" and the Norwegian "Tromso-7" study. From 2207 participants we identified 840 individuals (511 females and 329 males, age range 40-79) with normal cardiac function by excluding left ventricular ejection fraction &amp;lt;50%, moderate or severe valvular heart disease, LV- dilatation, pulmonary hypertension, Q-waves and bundle branch block signs on ECG, high blood pressure, history of heart attack, use of antihypertensive drugs or high level of NT-proBNP. End-systolic longitudinal epi- myo- and endocardial strain and peak systolic SR and diastolic SR E and SR A were assessed for the calculation of segmental normal ranges. In addition to noise and foreshortening artefacts, we introduced a concept of "curve artefact" which can be defined as unphysiological strain curve shapes. Panel A of the figure shows examples of these curve artefacts, A: diastolic mismatch B: blunted curve, and C: floating curve. All strain curves were assessed for the presence of one of these unphysiological shapes and 2D images were visually assessed for the presence of noise, reverberations, or missing parts of the myocardium. Results The bar-chart for segmental strain demonstrates significantly reduced strain values at the presence of curve artefacts and increased strain at the presence of foreshortening. Normal ranges for basal septal, basal, medial, and apical segments excluding segments with artefacts and foreshortening are displayed in the table. The presence of curve artefacts matched the presence of noise or other 2D image artefacts in 88% of cases. Conclusions Strain artefacts result in systematically reduced peak-strain values. Thus, the detection and exclusion of curve artefacts seem to be an important measure for the correct interpretation of strain curves for a definition of normalcy and pathology. The selection of artefact-free strain curves reveals high strain and SR gradients increasing from epi to endocardial position and basal-septal towards apical segments. Abstract Figure. normal range Abstract Figure. artefacts

Quantification of right ventricular electromechanical dyssynchrony by two-dimensional multi-plane echocardiography in adults with repaired Tetralogy of Fallot

Abstract Funding Acknowledgements Type of funding sources: None. Background Electromechanical dyssynchrony between right ventricular (RV) free wall and septum contraction in repaired Tetralogy of Fallot (ToF) contributes to inefficient RV mechanics and ultimately reduced systolic function (1). Whilst current assessment of RV synchronicity involves the lateral wall and septum, the use of two-dimensional multi-plane echocardiography (2D-MPE) enables additional RV walls to be evaluated, reflecting global myocardial dynamics (2). Purpose The aim of this study is to gain new insights into regional RV wall mechanics using 2D-MPE, determining the potential added value of this imaging model in the assessment of electromechanical synchronicity. Methods Twenty ToF patients and fifteen healthy controls underwent detailed RV assessment using 2D-MPE. Furthermore, all ToF patients underwent on the same day cardiac magnetic resonance imaging (cMRI). RV wall longitudinal strain (LS) and synchronicity of contraction were measured using speckle tracking in three different RV walls (lateral, anterior and inferior) and the RV septum. RV synchronicity was assessed by the time to peak (TTP) deformation delay between the basal RV wall and mid septal segment. Additionally, mechanical dispersion was calculated as the standard deviation of average TTP strain values across four (SD-4: basal-mid septal and lateral), six (SD-6: inclusive inferior wall) and eight segments (SD-8: inclusive anterior and inferior walls). Results RV wall average LS was significantly lower in ToF patients compared to the control group (-20.8 ± 4.0% vs -28.1 ± 3.6%, p = &amp;lt;0.001). In ToF patients, higher LS values were seen in the lateral (-21.5 ± 4.7%) and inferior (-20.7 ± 3.7%) walls compared to the anterior (-19.0 ± 4.5%) wall. RV wall to septum TTP delay was significantly increased for all segments in ToF patients compared to healthy controls (all p &amp;lt;0.03). In ToF patients, inferior wall-septum TTP delay was 50 [5, 89]ms whilst the lateral (65 [26, 81]ms) and anterior wall (66 [40, 98]ms) delay was longer. In healthy controls meanwhile, peak RV wall and septal deformation occurred almost simultaneously (table 1). SD-4 was significantly greater in ToF patients compared to controls (39 [23, 56]ms vs 14 [0, 21]ms, p = 0.001) however SD-6 and SD-8 were not significantly different (36 [22, 53]ms vs 22 [17, 35], p = 0.09; 31 [17, 51]ms vs 30 [20, 32]ms, p = 0.33). The association between mechanical dispersion measurements and cMRI-derived right ventricular ejection fraction (RVEF) strengthened with the inclusion of additional RV walls (SD-4 R² = -0.18; SD-6 R² = -0.18; SD-8 R² = -0.27). Conclusion 2D MPE provides new insights into RV regional deformation and evaluates the association between the mechanics of individual RV walls and the septum. Further research is required to expand upon this novel approach for the assessment of regional RV function. Abstract Table 1 Abstract Figure 1

Contouring cardiac substructures on average intensity projection 4D-CT for lung cancer radiotherapy: A proposal of a heart valve contouring atlas

Background and purposeA detailed contouring atlas of the heart valves is lacking. Existing heart contouring atlases have not been evaluated on average intensity projection four-dimensional non-contrast computed tomography (AVE-4D-CT) scans, routinely used for organ-at-risk delineation in lung cancer radiotherapy. We aimed to develop the heart valve contouring atlas and to assess inter-observer variation in delineation of the heart, its substructures, and coronary arteries on AVE-4D-CT scans, along with its impact on radiotherapy doses. Materials and methodsA heart valve contouring atlas was developed. Five radiation oncologists and four cardiologists delineated the valves according to this atlas, and the remaining heart substructures according to the existing atlases, on AVE-4D-CT scans of ten patients who underwent radio(chemo)therapy for NSCLC. The observer contours were then compared to the collectively defined “reference” contours. Spatial variation was assessed using the Sørensen-Dice similarity coefficient (DSC), directed average Hausdorff distance (DAH), directed Hausdorff distance (HD), and the mean distance to agreement (MDA). The effect of spatial variation on radiotherapy doses was assessed using the patients' treatment plans. ResultsInter-observer contour overlap (mean DSC) was 0.68, 0.49, 0.45 and 0.45, and inter-observer contour separation (mean DAH) was 2.1, 3.4, 2.6 and 2.9 mm for the pulmonic (PV), aortic (AV), mitral (MV) and tricuspid valve (TV), respectively. Mean HD was higher for TV and MV (13.3 and 11.7 mm) than for AV and PV (7.8 and 7 mm). The highest mean MDA of 3.1 mm was found for AV, and the lowest (1.9 mm) for PV. Inter-observer agreement was the lowest for the coronary arteries, but statistically significant dose variation was found mainly in the left ventricular septal and anterior segments. ConclusionOur atlas enables reproducible delineation of the heart valves. Delineation of the heart and its substructures on AVE-4D-CT scans is feasible, with inter-observer variability similar to that reported on conventional non-contrast CT scans.