Basal Septum Research Articles

How to Manage Mitral Stenosis Due to Mitral Annular Calcification.

Mitral annular calcification (MAC) is associated with cardiovascular comorbidities and events and in the presence of mitral stenosis (MS) represents a high-risk cohort with limited treatment options. Emerging hybrid, minimally invasive, and transcatheter therapies that use circumferential MAC as an anchor for mitral valve replacement are emerging, but none are consistently associated with ideal outcomes. In patients with MAC and nonrheumatic calcific mitral stenosis who are severely symptomatic, mitral intervention may be indicated. Surgical decalcification and replacement of the mitral valve remains the conventional therapy. Surgical techniques to avoid decalcification are being described including a left atrium to left ventricular apex graft conduit. Transcatheter balloon-expandable valves designed for the aortic valve have been implanted in the mitral position in MAC with a surgical direct transatrial transcatheter approach or transseptal transcatheter approach. Left ventricular outflow tract (LVOT) obstruction remains prevalent and associated with increased mortality. Direct transatrial approach allows for surgical resection of the anterior leaflet to mitigate this risk, and percutaneous therapies to lacerate the anterior leaflet or to ablate the basal septum are being developed. Cardiac computed tomography has emerged as a requisite for patient selection and procedural planning and has powerful predictive value for LVOT obstruction and valve embolization in valve-in-MAC. Novel transcatheter valves designed specifically for the mitral space are being studied in patients with MAC. MAC with mitral stenosis remains a challenging disease. Advances in technique, technology, and imaging may create new and reproducible treatment options with low procedural mortality for this challenging disease entity.

B-PO03-028 BIPOLAR PULSED ELECTRIC FIELD ABLATION OF THE INTERVENTRICULAR SEPTUM

Ablation of deep septal substrate with thermal energy sources conveys many challenges including inadequate lesion depth, inadvertent steam pops, and conduction system injury. Pulsed electric fields (PEF) were delivered across the interventricular septum as a preclinical proof-of-concept for transmural ablation through irreversible electroporation. In 8 healthy canine 4-week survival experiments, microsecond (n=2; 75-189J/animal) or nanosecond (n=6; 107-275J/animal) duration PEF were applied in a bipolar fashion between solid-tip ablation catheters positioned on either side of the septum in 2-5 separate locations. Radiofrequency (RF) control lesions were delivered for comparison at non-septal sites. Nanosecond PEF did not result in sustained ventricular tachyarrhythmias or skeletal muscle stimulation as opposed to microsecond PEF. Transient complete heart block was seen in 4 after delivery at the basal septum. Of these, bundle branch block persisted in 3 animals. Two animals died due to intractable VF during the initial experiment: 1 during microsecond delivery and another during an RF lesion. At 4 weeks of survival, 36 individual well-demarcated ablation lesions were demonstrated on both sides of the septum by cardiac MRI, necropsy, and histology. Lesion depth measured by histology was 2.62±2.06 mm with a maximum of 10.9 mm and transmurality in 1 animal. Bipolar irreversible electroporation of the interventricular septum is feasible and can result in transmural septal ablation lesions. Conduction system injury may occur at least transiently and further refinement is required to improve safety.

B-PO02-124 NONISCHEMIC LEFT VENTRICULAR CARDIOMYOPATHY WITH PRESERVED LEFT VENTRICULAR FUNCTION: A TYPE OF ARRHYTHMOGENIC CARDIOMYOPATHY

Ventricular tachycardia (VT) may occur in nonischemic cardiomyopathy (NICM) even when left ventricular (LV) systolic function is relatively preserved. The underlying substrate and response to ablation for these subjects are not well characterized. Describe ventricular substrate and ablation outcomes in NICM patients with sustained VT and relatively preserved LV function. Consecutive NICM patients undergoing ablation of LV VTs were reviewed. Those with arrhythmogenic right ventricular cardiomyopathy, cardiac sarcoidosis or only right ventricular VTs were excluded. Of 82 patients (63±14 years, LV ejection fraction [LVEF] 35±14%) , 20 (24%) had LVEF >45%. Of these, pathogenic gene mutations were identified in 7 (LMNA [3], TTN [1], DSP [2], CRYAB [1]). Low bipolar or unipolar was observed in relatively small areas (median 19 cm2) with a predilection for the basal septum and inferolateral epicardial regions (Figure). Ablation was acutely successful in 80% of patients, though 6 (30%) required advanced ablation techniques (needle ablation in 4, simultaneous unipolar ablation in 2) for presumed deep intramural substrate. VT storm was eliminated in 5 of 6 patients. At a median follow-up of 7.4 months, 7 (35%) patients had VT recurrence. The VT recurrence rate was similar to NICM patients with LVEF≤45% (log-rank p = 0.70). LV VT in patients with NICM and LVEF >45% is associated with small areas of scar and can have a genetic cause. The VT substrate is often intramural and difficult to ablate, with recurrence rates comparable to patients with LVEF < 45%.

B-PO02-126 LATE-IODINE ENHANCEMENT COMPUTED TOMOGRAPHY AS A MARKER FOR SCAR LOCALIZATION FOR VENTRICULAR TACHYCARDIA ABLATION IN CARDIAC SARCOIDOSIS

Ventricular tachycardia (VT) portends high morbidity and mortality in cardiac sarcoidosis (CS). Left ventricular scarring in CS is often patchy with a predilection for the basal septum, anterior wall, and perivalvular regions. Reliable pre-procedural imaging modalities as adjuvant tools for VT scar localization are limited. To assess anatomic correlation of late iodine enhancement with procedural scar localization and to determine whether such correlation predicts ablation success. Consecutive VT ablation procedures from January 2017 to December 2020 at the Medical University of South Carolina were retrospectively reviewed. Thirteen patients with CS underwent pre-procedural computed tomography (CT) to identify wall thinning (WT) and late iodine enhancement (LIE). Left ventricular scarring was confirmed with voltage mapping and classified based on anatomical region: LV ostium, anterior, septal, inferior, lateral, and apical. Fisher's exact probability extension for 2 x 2 contingency tables were used to test whether there was significant congruency of two modalities. The cohort included 13 patients with CS (92% male, 60 +/- 11 years, EF 40.9% +/- 12.5). Average procedure time was 279 +/- 89 minutes with > 1 inducible VT per case (8 LBBB, 6 RBBB; average CL 414 ms) in all patients. The presence of WT did not correlate with LIE at the LV ostium (p=0.19) but did with anterior (p=0.007), inferior (p=0.005), and lateral (p=0.005) regions. WT was not associated with scar localization. The presence of LIE demonstrated convergence with scar localization at the LV ostium (p=0.005). Of 6 patients with normal wall thickness and positive LIE at the LV ostium (i.e. discordance), 5 (83%) had noninducible VT substrate post-ablation. Of those 5 patients, 3 (60%) had arrhythmia recurrence and required repeat ablation. In patients with cardiac sarcoidosis, LIE on CT correlates with scar localization at the LV summit. Ablation of LIE-identified LV ostial scars yields a high rate of acute success in patients with CS. Future studies should investigate the association between WT-LIE-scar localization and long-term outcomes.

Septal late gadolinium enhancement on Cardiac MRI predicts failure to achieve left bundle pacing

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): British Heart Foundation Background; Left bundle area pacing is a novel technique that provides direct stimulation of cardiac conduction tissue in order to deliver physiological ventricular activation. The approach for left bundle area pacing is transseptal lead implantation, where the lead is advanced from the right ventricular side of the septum to the left ventricular side to capture the proximal left bundle. Observational data suggests that whilst this is a safe and feasible method, implant success rate is not 100%, and appears to be lower in patients with a cardiac resynchronization therapy (CRT) indication rather than a bradycardia indication for pacing. The mechanisms for failure to advance the lead through the ventricular septum are not well understood. Purpose; We used pre-procedural CMR to determine whether there are features which can help identify patients where lead implantation may be challenging. We assessed whether the extent and location of septal late gadolinium enhancement identified patients in whom left bundle area pacing will be challenging. We hypothesized that the presence of extensive scar in the septum impedes advancing the lead to the left ventricular septum and prevents capture of the left bundle. Methods; Patients underwent cardiac MRI including motion corrected free-breathing late gadolinium enhancement imaging1 before implantation. Scar was quantified using the full height half maximum method and expressed as the overall proportion of myocardial mass in the basal anteroseptal and basal inferoseptal segments, as shown in Figure 1. Left bundle area pacing was then attempted in patients with a CRT indication for pacing. We compared the extent of septal scar between patients in whom left bundle area pacing was achieved and those where there was failure to advance the lead deep into the septum. Results; 12 patients (11 male, 1 female), with average age 72 (IQR 63 to 78) and LVEF 30% (IQR 26 to 33) were studied. There was failure to advance the lead deep into the septum in 4 patients. There was a significantly higher basal septal scar burden in those patients where there was failure to advance the left bundle lead compared to those in which left bundle capture was achieved as shown in Figure 2 (median 55% and 5% respectively, p-value 0.02 by Wilcoxon signed rank test). Conclusion; The presence and extent of late gadolinium enhancement in the basal septum appears to be an important determinant of successful implantation of left bundle pacing lead using current implant technology. This may be because extensive septal scar prevents advancement of the pacing lead through the septum. Cardiac MRI before left bundle area pacing is likely to be useful in procedural planning.

Alcohol Septal Ablation: An Option on the Rise in Hypertrophic Obstructive Cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) can cause symptoms due to the obstruction of the left ventricle outflow tract (LVOT). Although pharmacological therapy is the first step for treating this condition, many patients do not fully respond to the treatment, and an invasive approach is required to manage symptoms. Septal reduction therapies include septal myectomy (SM) and alcohol septal ablation (ASA). ASA consists of a selective infusion of high-grade alcohol into a septal branch supplying the basal interventricular septum to create an iatrogenic infarction with the aim of reducing LVOT obstruction. Currently, SM and ASA have the same level of indication; however, ASA is normally reserved for patients of advanced age, with comorbidities or when the surgical approach is not feasible. Recent data suggests that there are no differences in short- and long-term all-cause mortality, cardiovascular mortality and sudden cardiac death between ASA and SM. Despite the greater experience and refinement of the technique gained in recent years, the most common complication continues to be complete atrio-ventricular block, requiring a permanent pacemaker. Septal reduction therapies should be performed in experienced centres with comprehensive programs.

Obesity in the absence of comorbidities is not related to clinically meaningful left ventricular hypertrophy

Obesity is associated with the development of left ventricular (LV) hypertrophy. Whether obesity in in the absence of comorbidities can cause LV hypertrophy to an extent which could create diagnostic uncertainty with pathological states (such as hypertrophic cardiomyopathy) is unknown. We used cine cardiovascular magnetic resonance imaging to precisely measure LV wall thickness in the septum and lateral wall in 764 people with body mass indices ranging from 18.5 kg/m2 to 59.2 kg/m2 in the absence of major comorbidities. Obesity was related to LV wall thickness across the cohort (basal septum r 0.30, P < 0.001 and basal lateral wall r 0.18, P < 0.001). Although no participant had hypertension, these associations remained highly significant after controlling for systolic blood pressure (all P < 0.01). Each 10 kg/m2 increase in BMI was associated with an increase in basal septal wall thickness of 1.0 mm males and 0.8 mm in females, with no statistically significant difference between genders (P = 0.1). Even in class 3 obesity (BMI > 40 kg/m2), no LV wall thickness > 13.4 mm in males or > 12.7 mm in females was observed in this cohort. We confirm that obesity in the absence of comorbidities is associated with LV hypertrophy, and establish that the magnitude of this change is modest even in severe obesity. LV hypertrophy > 14 mm cannot safely be attributed to obesity alone and alternative diagnoses should be considered.

Ventricular activation pattern assessment during right ventricular pacing: Ultra‐high‐frequency ECG study

Right ventricular (RV) pacing causes delayed activation of remote ventricular segments. We used the ultra-high-frequency ECG (UHF-ECG) to describe ventricular depolarization when pacing different RV locations. In 51 patients, temporary pacing was performed at the RV septum (mSp); further subclassified as right ventricular inflow tract (RVIT) and right ventricular outflow tract (RVOT) for septal inflow and outflow positions (below or above the plane of His bundle in right anterior oblique), apex, anterior lateral wall, and at the basal RV septum with nonselective His bundle or RBB capture (nsHBorRBBp). The timings of UHF-ECG electrical activations were quantified as left ventricular lateral wall delay (LVLWd; V8 activation delay)and RV lateral wall delay (RVLWd; V1 activation delay). The LVLWd was shortest for nsHBorRBBp (11 ms [95% confidence interval = 5-17]), followed by the RVIT (19 ms [11-26]) and the RVOT (33 ms [27-40]; p < .01 between all of them), although the QRSd for the latter two were the same (153 ms (148-158) vs. 153 ms (148-158); p = .99). RV apical capture not only had a longer LVLWd (34 ms (26-43) compared to mSp (27 ms (20-34), p < .05), but its RVLWd (17 ms (9-25) was also the longest compared to other RV pacing sites (mean values for nsHBorRBBp, mSp, anteriorand lateral wall captures being below 6 ms), p < .001 compared to each of them. RVIT pacing produces better ventricular synchrony compared to other RV pacing locations with myocardial capture. However, UHF-ECG ventricular dysynchrony seen during RVIT pacing is increased compared to concomitant capture of basal septal myocytes and His bundle or proximal right bundle branch.

Clinical and Prognostic Significance of Idiopathic Left Bundle-Branch Block in Young Adults.

Aims LBBB is rare in healthy young adults, and its long-term prognosis is uncertain. Methods 56 subjects (aged <50 years), in whom an LBBB was discovered by chance in the absence of clinical and echocardiographic evidence of heart disease, were collected in a multicenter registry. Results 69% were males. Mean age at the time of discovery of LBBB was 37 ± 11 years. Mean QRS duration was 149 ± 17 m sec and 35% had left axis deviation. All patients had a normal echocardiogram, except for left ventricular dyssynchrony; 37 patients underwent coronary angiography (30) or myocardial scintigraphy during effort Eriksson and Wilhelmsen (2005), and in all cases obstructive coronary artery disease was excluded. In 2/30 patients who underwent coronary angiography, an anomalous origin of the CX artery from the right coronary sinus was found. Thirty patients underwent cardiac magnetic resonance; in 60% it was normal, while in 40% it revealed late enhancement, which in 33% was localized in the basal septum, suggesting fibrosis of the left bundle branch. During follow-up (12+/10 years, median 10 years) no sudden death occurred. At the end of follow-up, all patients were alive, except for one who suffered accidental death. Two patients (3.5%) underwent PM implantation owing to syncope. The echocardiogram at the end of follow-up revealed LV dysfunction in only one patient. Conclusions In young adults without apparent heart disease, LBBB is a heterogeneous condition. In the vast majority of cases, the prognosis is good and no ventricular dysfunction occurs over time. However, as only 18% of our patients were aged >60 years at the end of follow-up, we cannot establish the prognosis in older age-groups.

Cardiac magnetic resonance and B-natriuretic peptide: prognostic value in patients with asymptomatic chronic aortic regurgitation

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This study was supported by Ministry of Health of the Czech Republic 17-28265A. Background Indication for surgical treatment in asymptomatic patients with severe aortic regurgitation (AR) is curretly based on 2-dimensional echocardiography derived left ventricle (LV) diameter and ejection fraction. Suboptimal sensitivity of this quideline-directed approach may lead to late intervention in a substantial number of patients. Purpose We aimed to develop a new prognostic stratification scheme based on novel imaging and biochemical markers of heart failure. Methods Consecutive patients with chronic severe AR not indicated for surgery per the current guidelines were enrolled into prospective multi-center study. Baseline examination consisted of B-natriuretic peptide (BNP); comprehensive echocardiography (ECHO) including 3-dimensional (3D) vena contracta area (VCA); comprehensive cardiac magnetic resonance (CMR) including regurgitant volume and fraction measurement, and extracellular volume (ECV); all imaging data were analysed in core lab. The perioperative myocardial biopsy from basal septum was performed in all surgically treated patients for histological myocardial fibrosis quantification by Picrosirius Red staining. Patient follow-up was every 6 months. The endpoint was a disease progression (indication for surgery per the current guidelines). Results In total, 132 patients were enrolled between 2015 and 2019, the endpoint occurred in 39 patients during a median follow-up of 1217 days. Baseline clinical data did not differ between patients with endpoint (surgical group) and stable patients (medical group). Baseline BNP levels were higher in the surgical group (57 vs. 20, P &amp;lt; 0.01). Most baseline ECHO parameters did not differ, only 3D VCA, mitral inflow E-wave and flow reversal velocity in the descending aorta were significantly different between two groups (33 vs. 25 mm2, 61 vs 68 cm/s, 21 vs. 19 cm/s with P = 0.012, P = 0.019, P = 0.001). Both CMR-derived end-systolic and end-diastolic LV volumes were significantly different (all P &amp;lt; 0.01); the LV ejection fraction was similar (61 vs. 61%, P = 0.83). The ECV was similar in both groups (24.2 vs. 24%, P = 0.69) and correlated well with histologically validated diffuse myocardial fibrosis (15%). CMR-derived regurgitant volume and fraction were significantly higher in the surgical group (58 vs. 36 ml, P &amp;lt; 0.01 and 45 vs. 33%, P &amp;lt; 0.01). Based on our results, we developed a multi-factorial scoring system combining the independent predictors of disease progression (specificity 79%, sensitivity 74%). Conclusion Baseline CMR-derived LV volumes, CMR-derived regurgitant fraction, and BNP levels can predict disease progression in asymptomatic patients with chronic severe aortic regurgitation. The novel multi-factorial scoring system might identify candidates of early surgical treatment but this hypothesis will require prospective clinical testing. Abstract Figure. Cardiac magnetic resonance imaging

Aetiology-discriminative multimodality imaging of hypertrophic cardiomyopathy: deformation patterns relate to synchrotron-based assessment of microstructural tissue remodelling

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Horizon 2020 European Commission Project H2020-MSCA-ITN-2016 (764738) and the Clinical Research in Cardiology grant from the Spanish Cardiac Society. Background The aetiology of left ventricular hypertrophy (LVH) is a relevant clinical challenge with consequences for patient management. Phenotypes resulting from hypertensive remodelling and sarcomere mutation often overlap. Synchrotron X-ray phase-contrast imaging (X-PCI) is a technique that can provide 3-dimensional detailed information on myocardial micro-structure non-destructively. The aim is to relate macrostructural/functional, non-invasive, imaging phenotypes of hypertrophic cardiomyopathy (HCM) to the underlying myocardial microstructure assessed with X-PCI. Methods Myocardial tissue samples were obtained from three patients (P1-3) with obstructive myocardial hypertrophy undergoing septal myectomy. Medical history and the 5-year HCM risk scores were evaluated. The patients were imaged with magnetic resonance imaging and echocardiography prior to procedure. Myocardial structure was assessed with wall thickness, late gadolinium enhancement (LGE), whereas function with speckle-tracking deformation (STE) and tissue Doppler imaging (TDI). Myectomy tissue was imaged with X-PCI in the TOMCAT beamline, using a multiscale propagation-based protocol combining a low-resolution (LR) and a high-resolution (HR) setup (5.8 and 0.7 um pixel size, respectively). Results The clinical and imaging data are shown in Fig 1. On initial assessment, wall thickness, LGE distribution, global longitudinal strain and septal TDI demonstrated a similar macrostructural and functional phenotype of P1 and P2, whereas P3 stood out with more severe hypertrophy, scarring and dysfunction. Additional regional deformation analysis with STE revealed reduced deformation in the basal and mid septum in P1, paired with a hypertensive pattern of post-systolic shortening (PSS) (yellow arrows). In comparison, in P2 and P3, deformation was more heterogeneous regionally, with regions of almost complete absence of deformation (orange arrows). Upon further exploration with TDI, areas with abnormal deformation were identified on the transition from basal to mid septum in both P2 and P3, whereas deformation was normal, but reduced in P1, and paired with PSS. LR X-PCI defined regions of interest to scan with HR (yellow frame), where HR revealed extensive interstitial fibrosis (orange arrow) with normal myocyte size and organisation in P1, compatible with severe hypertensive remodelling. However, in P2 and P3, patches of fibrosis (yellow arrow) paired with enlarged myocytes organized in visible disarray, considerably more prominent in P3, were both compatible with sarcomere-mutation HCM. Conclusion The results demonstrate multiscale phenotyping of HCM - relating micro- and macrostructural findings to function, and integrating multimodality data. In-depth regional deformation analysis, validated by synchrotron-based microstructural analysis, showed potential to identify distinct imaging phenotypes in HCM, distinguishing between overlapping presentations in different aetiologies. Abstract Figure 1

Clinical and Electrophysiologic Characteristics of Ventricular Tachycardias from the Basal Septum in Structural Heart Disease

Background The basal septum is a common source of ventricular tachycardia (VT) in patients with structural heart disease (SHD).ObjectiveWe describe the clinical and electrophysiologic characteristics of basal septal VTs in SHD patients.MethodsData from 312 consecutive SHD patients undergoing catheter ablation of ventricular arrhythmias were reviewed.ResultsThirty-three basal-septal VTs in 31 patients (mean age 67.4{plus minus}14.2 years, left ventricular [LV] ejection fraction [EF] 42{plus minus}15%) were identified. Patients with VTs with LV basal-septal breakthrough were more likely to have ischemic cardiomyopathy and a lower LVEF; right ventricular basal-septal VT patients were more likely to have sarcoidosis or right ventricular cardiomyopathy of unknown significance, with a higher LVEF. Atrioventricular block was present in 45% and intraventricular block including persistent bi-ventricular pacing in 77%. Unipolar scar was larger than bipolar scar (area 18.8{plus minus}19.4% vs. 12.7{plus minus}14.6%, P<0.001). VTs with a right bundle branch block (BBB) morphology and S wave in V6 with positive V3/V4 polarity consistently indicated an LV basal-septal breakthrough. Inferior limb-lead discordance with a right BBB morphology and reverse pattern break in V2 were identified in LV basal infero-septal origin in 3 patients respectively. VT non-inducibility was achieved in 55% and VT recurred in 42% of patients after a single procedure, however, VT burden was significantly reduced after ablation (59 episodes pre vs. 2 episodes post, P=0.02).ConclusionBasal-septal VTs in SHD have a distinct clinical, electrocardiographic, and electrophysiologic profile depending on the breakthrough site, accompanied by a deep intramural septal substrate that limits procedural success after catheter ablation.

Activation of cardiac sarcoidosis associated with development of gastric cancer: a case report

BackgroundThe high 18F-fluorodeoxyglucose (FDG) uptake in sarcoidosis lesions reflects infiltration of inflammatory cells such as macrophages. An increased incidence of cancer in patients with sarcoidosis has been suggested, and some combination of the following mechanisms has been proposed: chronic inflammation, immune dysfunction, shared aetiologic agents, and genetic susceptibility to both cancer and autoimmune diseases.Case summaryA 73-year-old man was admitted to our hospital due to effort dyspnoea. Initial investigations showed complete atrioventricular block on electrocardiography, basal thinning of the interventricular septum, and preserved left ventricular (LV) systolic function on echocardiography, and late gadolinium enhancement (LGE) in all layers of the basal interventricular septum on cardiac magnetic resonance imaging. FDG positron emission tomography/computerized tomography (FDG-PET/CT) showed no abnormal uptake in the whole-body including myocardium. After discussion, corticosteroid was not initiated then. One year later, he developed stomach adenocarcinoma. Repeated investigations demonstrated enlargement of the LV (LV diastolic diameter 63 mm) and diffuse systolic impairment of LV function (LV ejection fraction 31%) on echocardiography, and abnormal focal uptake at the lateral walls of LV and hilar lymph nodes on FDG-PET/CT imaging. One more year after the surgery for gastric cancer and corticosteroid initiation, echocardiography showed recovery of systolic function and FDG-PET/CT showed no uptake in either the myocardium or hilar lymph nodes.DiscussionIn the present case, it is speculated that the first inflammation which left scarred areas showing LGE was already completed before the first FDG-PET/CT. The development of gastric cancer may be associated with the reactivation of cardiac sarcoidosis.

Surface unipolar electrogram characteristics to predict site of origin of outflow tract arrhythmias using noninvasive mapping.

Noninvasive electroanatomic mapping (NIEAM) demonstrate patterns of depolarization that are useful in identifying the chamber of origin (COO) in outflow tract ventricular arrhythmias (OTVA). However, its use in predicting exact site of origin (SOO) has not yet been validated. NIEAMs (CardioInsight, Medtronic) from 40 patients (age 62.5 ± 2.6) undergoing ablation for OTVA were reviewed for diagnostic accuracy in predicting the SOO. Earliest arrhythmia breakout and directionality of earliest instantaneous unipolar electrograms (uEGMs) on NIEAMs were evaluated subjectively by two observers for quality and amplitude. Sites with most negative earliest uEGMs on right and left ventricular outflow tracts, as well as epicardial surface were manually identified. Using NIEAM-based activation timing of the lateral mitral annulus and basal septum COO was identified for each OTVA. Predictions of SOO using NIEAMs was compared with true SOO from invasive study. NIEAMs SOO predictions were compared with subjective 12 lead electrocardiogram (ECG) review by two observers. Review of arrhythmia breakout and signal directionality had poor diagnostic value in predicting SOO in OTVA (50.6% and 49.4%, 56.6% and 43.4%, respectively) and underperformed compared with ECG interpretation (59.1% and 80.5%). After excluding uEGMs with poor characteristics, the uEGM with most negative amplitude at the COO was predictive of the true SOO with 96.4% sensitivity and specificity. We propose a stepwise approach when interpreting NIEAMs for OTVA where patterns of activation are evaluated first to determine the COO, followed by identification of the site with most negative amplitude instantaneous uEGM to determine SOO.

Cardiovascular magnetic resonance normal values in children for biventricular wall thickness and mass

BackgroundPediatric patients are becoming increasingly referred for cardiovascular magnetic resonance (CMR). Measurement of ventricular wall thickness is typically part of the assessment and can be of diagnostic importance, e.g. in arterial hypertension. However, normal values for left ventricular (LV) and right ventricular (RV) wall thickness in pediatric patients are lacking. The aim of this study was to establish pediatric centile charts for segmental LV and RV myocardial thickness in a retrospective multicenter CMR study.MethodsCMR was performed in 161 healthy children and adolescents with an age range between 6 and 18 years from two centers in the UK and Germany as well as from a previously published CMR project of the German Competence Network for Congenital Heart Defects. LV myocardial thickness of 16 segments was measured on the short axis stack using the American Heart Association segmentation model. In addition, the thickness of the RV inferior and anterior free wall as well as biventricular mass was measured.ResultsThe mean age (standard deviation) of the subjects was 13.6 (2.9) years, 64 (39.7%) were female. Myocardial thickness of the basal septum (basal antero- and inferoseptal wall) was 5.2 (1.1) mm, and the basal lateral wall (basal antero- and inferolateral) measured 5.1 (1.2) mm. Mid-ventricular septum (antero- and inferoseptal wall) measured 5.5 (1.2) mm, and mid-ventricular lateral wall (antero- and inferolateral wall) was 4.7 (1.2) mm. Separate centile charts for boys and girls for all myocardial segments and myocardial mass were created because gender was significantly correlated with LV myocardial thickness (p < 0.001 at basal level, p = 0.001 at midventricular level and p = 0.005 at the apex) and biventricular mass (LV, p < 0.001; RV, p < 0.001).ConclusionWe established CMR normal values of segmental myocardial thickness and biventricular mass in children and adolescents. Our data are of use for the detection of abnormal myocardial properties and can serve as a reference in future studies and clinical practice.

Use of strain, strain rate, tissue velocity imaging, and endothelial function for early detection of cardiovascular involvement in young diabetics

Background:Subtle structural and functional changes may precede the onset of overt global left ventricular (LV) dysfunction. Data pertaining to tissue velocity imaging (TVI)and strain imaging to assess regional myocardial function and flow mediated vasodilatation are limited in young patients with diabetes.Materials:Conventional echocardiography, TVI parameters along with strain (S), and strain rate (SR) were measured in 50 young diabetics (15.16 ± 2.95 years, mean HBA1c 8.15 ± 1.37 g %) and 25 controls (15.60 ± 2.51 years). Flow-mediated dilation (FMD), nitrate--mediated dilatation (NMD), and carotid intima–media thickness were also assessed.Results:Conventional echocardiography parameters were similar in patients and controls; however, deceleration time of the mitral inflow velocity (early deceleration time) was significantly shorter in patients when compared with controls (149.06 ± 31.66 vs. 184.56 ± 19.27 ms, P =0.001). Patients had lower strain values at the basal lateral LV (21.39 ± 4.12 vs. 23.78 ± 2.02; P =0.001), mid-lateral LV (21.43 ± 4.27 vs. 23.17 ± 1.92 P =0.02), basal septum (20.59 ± 5.28 vs. 22.91 ± 2.00; P = 0.01), and midseptum (22.06 ± 4.75 vs. 24.10 ± 1.99; P = 0.01) as compared to controls. SR at the basal and midsegments of the lateral LV wall and at the basal septum was also significantly lower in diabetic patients. Diabetic children also had endothelial dysfunction with significantly lower FMD (8.36 ± 4.27 vs. 10.57 ± 4.12, P = 0.04).Conclusions:LV strain indices and flow--mediated dilatation are impaired in asymptomatic children and adolescents with type 1 diabetes mellitus despite absence of overt heart failure and normal ejection fraction. Early detection of subclinical regional myocardial dysfunction by deformation analysis including strain and strain rate may be useful in the asymptomatic diabetic population.

Caseous Calcification of the Mitral Annulus Presenting with Complete Heart Block

Caseous Calcification of the Mitral Annulus (CCMA) is a rare variant of Mitral Annular Calcification (MAC), which is usually a benign condition that is associated with people above the age of 85. It is usually incidentally diagnosed on echocardiography. This is a case of a relatively young patient who presented to hospital with chest discomfort and dizziness due to CCMA that had infiltrated the basal septum resulting in an infra-Hisian atrioventricular (AV block).

GCT-55. INTRACRANIAL GERMINOMA ORIGINATING FROM ATYPICAL LOCATION WITH SUBCLINICAL ADH INSUFFICIENCY

INTRODUCTIONIntracranial germinomas are rare tumors which usually develop in the midline structures and affect in 90% of cases the pineal gland and suprasellar regions. Sometimes they involve basal ganglia, septum pellucidum, and other regions. We report a very unusual presentation of an intracranial germinoma originating from the lateral ventricle.METHODSA 10-year-old boy presented with a 1-year history of polydipsia and polyuria. During the hypertonic saline test, a low ADH was detected and established the diagnosis of subclinical ADH insufficiency. MRI showed a heterogeneously enhancing periventricular lesion in the lateral ventricle, but no other abnormal findings, including hypophyseal stalk. Initially, the correlation of imaging findings and clinical symptoms were not clear. With suspected subependymoma, tumor removal was performed by small craniotomy. Since the intra-operative pathological diagnosis was germinoma, we performed only partial removal of the tumor. After establishing the histological diagnosis of germinoma, the patient received chemotherapy using carboplatin and etoposide, followed by radiation therapy. MRI showed no recurrence for five years after treatment. RESULTS/CONCLUSIONOur case presents two atypical features. First, intracranial germinoma originating from the lateral ventricle is quite rare. Though the cases with intracranial germinoma originating from septum pellucidum and corpus callosum have been reported, this case is even different. Second, imaging findings did not match clinical symptoms. The cause of subclinical ADH deficiency may be the occult hypophyseal germinoma. In conclusion, we report a 10-year-old case with a very unusual presentation of an intracranial germinoma originating from the lateral ventricle.

The value of left ventricular longitudinal strain in the diagnosis and differential diagnosis of myocardial amyloidosis

Objective: To investigate the characteristics of left ventricular longitudinal strain (LS) in myocardial amyloidosis (CA), hypertrophic cardiomyopathy (HCM) and Fabry disease (FD), as well as the correlation between left ventricular LS and these diseases. Methods: A total of 14 CA patients, 28 HCM patients and 5 FD patients who visited the Department of Cardiology of the First Affiliated Hospital of Suzhou University from June 2017 to November 2019 were retrospectively included. EchoPAC software was used to analyze left ventricular LS, and univariate logistic regression analysis was used to analyze the correlation between echocardiographic LS indexes and various myocardial hypertrophy diseases. The receiver operating characteristic (ROC) curve was used to assess the sensitivity and specificity of echocardiograph LS indexes in the diagnosis of various myocardial hypertrophy diseases. Results: There were significant differences in LS of left ventricular basal segment, inferior wall, posterior wall, lateral wall and posterior septum among the three groups (P<0.05). The absolute value of LS in the left ventricular basal segment decreased in the CA group; the absolute value of LS in left ventricular posterior wall and lateral wall decreased significantly in the FD group (P<0.05); the absolute values of LS in left ventricular basal segment, inferior wall, posterior septum, lateral wall and posterior wall increased significantly in the HCM group (P<0.05). The absolute value of LS < 7.9% in the left ventricular basal segment, or > 13.2% in the inferior wall and > 9.2% in the basal segment, or < 8.3% in the lateral wall and < 7.9% in the posterior wall were the indicators of high sensitivity and specificity in the diagnosis of CA, HCM and FD, respectively. Conclusions: Left ventricular LS was an important index to differentiate myocardial hypertrophy. Combined with their respective clinical characteristics, it could provide certain reference value for clinical practice.

Abstract 15426: Comparison of Multimodality Imaging in Mitral Leaflet Lengths in Patients Undergoing Surgical Myectomy: A Prospective Study in Hypertrophic Obstructive Cardiomyopathy Patients

Introduction: In hypertrophic obstructive cardiomyopathy (HOCM), mitral valve (MV) leaflets in often contribute to left ventricular outflow tract obstruction (LVOTO). Hence, MV assessment is crucial during surgical planning. 2 or 3-dimensional transesophageal echocardiography (2D or 3D TEE) &amp; cardiac magnetic resonance (CMR) are used to measure MV length. Hypothesis: We sought to compare MV leaflet lengths using intraoperative TEE [2D, zoom 3D, automatic quantification of mitral valve (AMVQ)], &amp; preoperative CMR. Methods: We prospectively studied 50 HOCM patients (59±12 years, 46% men, basal septum 18±5 mm, LVOT gradient 87 ±56 mmHg) undergoing surgical relief of LVOTO. We compared MV leaflet length on a) long-axis 2DTEE b) 3DTEE using multiplanar reconstruction c) AMVQ, EchoPAC, General Electric &amp; d) CMR. Results: Mean anterior leaflet lengths (mm) were as follows: 2D TEE (3.3 ±0.3), 3DTEE (2.9±0.5), CMR (3.1±0.4), &amp; AMVQ (2.9±0.5). Mean posterior leaflet lengths were 1.7±0.3, 1.7±0.4, &amp; 1.7±0.2 &amp; 1.9±0.4 mm, respectively. Assuming 3DTEE as the gold standard, the closest correlation for anterior leaflet was with CMR (average overestimation by CMR of 0.5 mm [root mean square deviation or RMSE% 17]), intermediate correlation with 2DTEE (average deviation of 0.6 mm [RMSE%:21]) &amp; no correlation with AMVQ (deviation of 0.7mm [RMSE% 24]), Fig 1A-C &amp; 2A-C. No correlation was found for posterior leaflet,Fig 1D-F &amp; 2D-F. Conclusions: There are significant differences in measuring MV lengths using different imaging techniques. In HOCM patients undergoing surgery, precise measurement of MV leaflet lengths is crucial &amp; extrapolation from one technique to other is not recommended.