Basal Interventricular Septum Research Articles

Predictive value of cardiac 18F-fluorodeoxyglucose positron emission tomography for fatal ventricular arrhythmic events in patients with cardiac sarcoidosis

Abstract Background Patients with cardiac sarcoidosis (CS) face an elevated risk of fatal ventricular arrhythmic events (FVAE), including sudden cardiac death. Late gadolinium enhancement (LGE) from contrast-enhanced cardiac magnetic resonance is used for diagnosis of CS and estimation of FVAE risk. However, its application is limited in cases with cardiac devices, renal failure or contrast agent allergies. 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) emerges as a diagnostic tool for CS, even in cases where LGE is not feasible. Purpose This study aimed to investigate the potential utility of FDG-PET in predicting FVAE in patients with CS by hypothesizing that higher or lower percent FDG uptake could predict the FVAE risk. Methods Cardiac FDG-PET data from 121 patients with CS, acquired at our university hospital between March 2008 and November 2020, were analyzed. A polar-map model was used to calculate percent uptake relative to maximal cardiac FDG uptake in each of the American Heart Association (AHA) 17 segments (Figure A). Percent uptakes of the AHA 17 segments were compared between groups with and without future FVAE. LGE information was available in 82 patients and was used to assess the presence of LGE in regions where percent FDG uptake differed between the two groups. Results Among enrolled patients (mean age 59.5 ± 10.0 years, 67.8% women), 43 experienced FVAE following FDG-PET image acquisition. The group with future FVAE had a higher history of FVAE (7.7% vs. 37.2%) and beta-blocker administration (38.5% vs. 60.5%), larger left ventricular diastolic diameter (LVDd) (49.3 ± 7.3 mm vs. 57.4 ± 9.5 mm) and lower ejection fraction (LVEF) (56.6 ± 13.6% vs. 42.0 ± 15.2%) compared to the group without it (P < 0.05 all). Percent FDG uptake in the basal interventricular septum part (segment 3) (Figure A) was lower in patients with future FVAE compared to those without it (54.4 ± 13.8% vs. 41.8 ± 15.2%, P < 0.001 corrected for multiple comparisons). Kaplan-Meier analysis with a median split of percent FDG uptake in segment 3 showed that patients with lower uptake (<49%, N= 62) had lower FVAE-free survival compared to those with higher uptake (≥49%, N = 59) (P = 0.007) (Figure B). A Cox hazard model also demonstrated an association between percent FDG uptake in segment 3 and FVAE onset (hazard ratio 0.972 [95% CI 0.951, 0.995], P = 0.015) after adjusting for previous FVAE, beta-blocker administration, LVDd and LVEF. Similarly, analysis within the subgroup with LGE in the septum (N = 58) revealed a higher risk of FVAE in the group with lower percent FDG uptake compared to those with higher uptake (P = 0.020) (Figure C(a)). However, this association was not evident in patients without LGE in the septum (N = 24) (P = 0.821) (Figure C(b)). Conclusions Reduced percent FDG uptake with LGE in the basal intraventricular septum may serve as a valuable predictor of future FVAE occurrence in patients with CS.

Reduced 18F-FDG uptake in the basal interventricular septum as a predictor of fatal ventricular arrhythmic events in patients with cardiac sarcoidosis

BackgroundPatients with cardiac sarcoidosis (CS) are at an increased risk of fatal ventricular arrhythmic events (FVAE). However, the predictive value of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) in assessing the risk of FVAE in patients with CS remains uncertain. MethodsWe included data from 121 patients with CS (39 men and 82 women; mean age: 59.5 years) who underwent FDG-PET imaging between March 2008 and November 2020, with follow-ups completed in July 2023. Of these, 82 patients had available cardiac magnetic resonance imaging data, including late gadolinium enhancement (LGE). FDG-PET images were analysed using a polar-map model to determine the regional mean percentage uptake relative to the maximal cardiac 18F-FDG uptake in each of the 17 segments defined by the American Heart Association. ResultsPatients experiencing FVAE after FDG-PET (n = 43) showed lower percent uptake in the basal inferoseptal segment compared to those who did not (n = 78) (41.8 ± 15.2 % vs. 54.4 ± 13.8 %, P < 0.001). Patients with a basal inferoseptal percent uptake below the median had a lower FVAE-free survival rate than those with a higher percent uptake (58.1 % vs. 78 % at 5 years, P = 0.007), which was consistent in patients with LGE in the same regions with reduced 18F-FDG uptake. A Cox hazard model indicated that the FVAE risk decreased with a hazard ratio of 0.862 (95 % CI 0.770–0.964) for every 5 % increase in basal inferoseptal percent uptake (P = 0.009). ConclusionReduced 18F-FDG uptake in the basal interventricular septum, including the inferoseptal segment, may be a valuable predictor of future FVAE in patients with CS.

Association Between Right Bundle Branch Block and Ventricular Arrhythmia in Patients With Cardiac Sarcoidosis

BackgroundVentricular arrhythmia (VA) is a life-threatening condition associated with cardiac sarcoidosis (CS). Right bundle branch block (RBBB) is a common conduction disorder in CS; however, its association with VA remains unknown. ObjectivesThis study aimed to investigate the relationship between RBBB and VA in patients with CS. MethodsThis was a post hoc analysis of ILLUMINATE-CS (Illustration of the Management and Prognosis of Japanese Patients with Cardiac Sarcoidosis), a multicenter, retrospective, and observational study that evaluated the clinical characteristics and prognosis of CS. Eligible patients were divided into two groups based on the presence or absence of RBBB at the time of diagnosis. The primary outcome was serious ventricular arrhythmia events (SVAEs), defined as a combination of sudden cardiac death and documented ventricular fibrillation, sustained ventricular tachycardia, or appropriate implantable cardioverter-defibrillator therapy. ResultsOverall, 312 patients were studied, with 155 (49.7%) patients presenting with RBBB (RBBB group). Patients in the RBBB group had a higher prevalence of basal interventricular septum (IVS) thinning and prominent late gadolinium enhancement in the basal IVS on cardiac magnetic resonance imaging than those in the non-RBBB group. During a median follow-up of 3.0 years (IQR: 1.6-6.0 years), 66 patients experienced SVAE. In multivariable Cox regression analysis, the RBBB group was independently associated with a higher incidence of SVAEs (HR: 1.93 [95% CI: 1.14-3.28]; P = 0.015). ConclusionsIn patients with CS, RBBB was an independent predictor of SVAEs, which might reflect the specific scar distribution that is predominant in the IVS.

Efficacy and safety of focal pulsed-field ablation for ventricular arrhythmias: two-centre experience.

A pulsed electric field (PF) energy source is a novel potential option for catheter ablation of ventricular arrhythmias (VAs) as it can create deeper lesions, particularly in scarred tissue. However, very limited data exist on its efficacy and safety. This prospective observational study reports the initial experience with VA ablation using focal PF. The study population consisted of 44 patients (16 women, aged 61 ± 14years) with either frequent ventricular premature complexes (VPCs, 48%) or scar-related ventricular tachycardia (VT, 52%). Ablation was performed using an irrigated 4 mm tip catheter and a commercially available PF generator. On average, 16 ± 15 PF applications (25 A) were delivered per patient. Acute success was achieved in 84% of patients as assessed by elimination of VPC or reaching non-inducibility of VT. In three cases (7%), a transient conduction system block was observed during PF applications remotely from the septum. Root analysis revealed that this event was caused by current leakage from the proximal shaft electrodes in contact with the basal interventricular septum. Acute elimination of VPC was achieved in 81% patients and non-inducibility of VT in 83% patients. At the 3-month follow-up, persistent suppression of the VPC was confirmed on Holter monitoring in 81% patients. In the VT group, the mean follow-up was 116 ± 75 days and a total of 52% patients remained free of any VA. Pulsed electric field catheter ablation of a broad spectrum of VA is feasible with acute high efficacy; however, the short-term follow-up is less satisfactory for patients with scar-related VT.

Interventricular septal thickness on cardiac computed tomography as a novel risk factor for conduction disturbances in patients undergoing transcatheter aortic valve replacement.

We examined whether thickness of the basal muscular interventricular septum (IVS), as measured by pre-procedural computed tomography (CT), could be used to identify the risk of conduction disturbances following transcatheter aortic valve replacement (TAVR). The IVS is a pivotal region of the electrical conduction system of the heart where the atrioventricular conduction axis is located. Included were 78 patients with severe aortic stenosis who underwent CT imaging prior to TAVR. The thickness of muscular IVS was measured in the coronal view, in systolic phases, at 1, 2, 5, and 10 mm below the membranous septum (MS). The primary endpoint was a composite of conduction disturbance following TAVR. Conduction disturbances occurred in 24 out of 78 patients (30.8%). Those with conduction disturbances were significantly more likely to have a thinner IVS than those without conduction disturbances at every measured IVS level (2.98 ± 0.52 mm vs. 3.38 ± 0.52 mm, 4.10 ± 1.02 mm vs. 4.65 ± 0.78 mm, 6.11 ± 1.12 mm vs. 6.88 ± 1.03 mm, and 9.72 ± 1.95 mm vs. 10.70 ± 1.55 mm for 1, 2, 5 and 10 mm below MS, respectively, P < 0.05 for all). Multivariable logistic regression analysis showed that pre-procedural IVS thickness (<4 mm at 2 mm below the MS) was a significant independent predictor of post-procedural conduction disturbance (adjOR 7.387, 95% CI: 2.003-27.244, P = 0.003). Pre-procedural CT assessment of basal IVS thickness is a novel predictive marker for the risk of conduction disturbances following TAVR. The IVS thickness potentially acts as an anatomical barrier protecting the underlying conduction system from mechanical compression during TAVR.

Ethnicity differences in geometric remodelling and myocardial composition in hypertension unveiled by cardiovascular magnetic resonance.

Hypertensive patients of African ancestry (Afr-a) have higher incidences of heart failure and worse clinical outcomes than hypertensive patients of European ancestry (Eu-a), yet the underlying mechanisms remain misunderstood. This study investigated right (RV) and left (LV) ventricular remodelling alongside myocardial tissue derangements between Afr-a and Eu-a hypertensives. 63 Afr-a and 47 Eu-a hypertensives underwent multi-parametric cardiovascular magnetic resonance. Biventricular volumes, mass, function, mass/end-diastolic volume (M/V) ratios, T2 and pre-/post-contrast T1 relaxation times, synthetic extracellular volume, and myocardial fibrosis (MF) were measured. 3D shape modelling was implemented to delineate ventricular geometry. LV and RV mass (indexed to body-surface-area) and M/V ratio were significantly greater in Afr-a than Eu-a hypertensives (67.1 ± 21.7 vs. 58.3 ± 16.7 g/m2, 12.6 ± 3.48 vs. 10.7 ± 2.71 g/m2, 0.79 ± 0.21 vs. 0.70 ± 0.14 g/mL, and 0.16 ± 0.04 vs. 0.13 ± 0.03 g/mL, respectively; P < 0.03). Afr-a patients showed greater basal interventricular septum thickness than Eu-a patients, influencing LV hypertrophy and RV cavity changes. This biventricular remodelling was associated with prolonged T2 relaxation time (47.0 ± 2.2 vs. 45.7 ± 2.2 ms, P = 0.005) and higher prevalence (23% vs. 4%, P = 0.001) and extent of MF [2.3 (0.6-14.3) vs. 1.6 (0.9-2.5) % LV mass, P = 0.008] in Afr-a patients. Multivariable linear regression showed that modifiable cardiovascular risk factors and greater end-diastolic volume, but not ethnicity, were independently associated with greater LV mass. Afr-a hypertensives had distinctive biventricular remodelling, including increased RV mass, septal thickening and myocardial tissue abnormalities compared with Eu-a hypertensives. From this study, modifiable cardiovascular risk factors and ventricular geometry, but not ethnicity, were independently associated with greater LV myocardial mass.

Association between left ventricular strain and fibrosis in severe aortic regurgitation with preserved ejection fraction: a magnetic resonance and histology study

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Institutional Grant Na Homolce Hospital Background The presence and extent of myocardial fibrosis are associated with poor outcomes in patients with severe aortic regurgitation. In the present study, we tested a correlation between left ventricular (LV) strain derived by using feature-tracking cardiac magnetic resonance (MRI) and diffuse myocardial fibrosis percentage (DMF%) at quantitative histology. Methods A study population included 23 patients (age 51 ± 12 years, 78% males) who underwent perioperative myocardial biopsy during aortic valve surgery for severe aortic regurgitation and who had a satisfactory pre-surgery MRI. Myocardial specimens obtained with a deep needle technique from the basal interventricular septum were stained with picrosirius red, digitalized, and analyzed using Image J software by a pathologist blinded to imaging findings. The DMF% was calculated as a ratio of the total collagen content to the total area. MRI-derived global longitudinal-(GLS), circumferential- (GCS), and radial (GRS) strain, as well as their ratio to heart rate and systolic blood pressure, were assessed using a feature-tracking technique by a certified imager blinded to histological analysis. Results Compared to normal values, all patients showed increased DMF% (19 ± 9%) and decreased GLS (15 ± 2%) despite preserved LV ejection fraction (64 ± 7%). Out of all the imaging parameters, only GLS/heart rate ratio, GCS/heart rate ratio and extracellular volume fraction showed a significant correlation with DMF% (Table 1, Figure 1). In contrast, GLS and GCS only tended to correlate with DMF%. The remaining parameters including GRS did not show a significant association. Patients with focal midwall scar in late gadolinium enhancement imaging (n=8, 35%), which was mainly localized in the basal septum, had similar GLS as than patients without focal scar (14.5±2.3 vs 15.3±2.3, p = 0.768). Conclusions Feature-tracking-derived ratios of LV GLS and GCS over heart rate are the most promising indices for non-invasive assessment of diffuse myocardial fibrosis in severe aortic regurgitation with preserved ejection fraction. Figure 1 Legend Correlation of a GLS/HR ratio 1A) and GLS 1B) with diffuse myocardial fibrosis %. Myocardial histology stained with Picrosirius red (collagen fibers are in red).

Relationship between mitral valve echocardiographic parameters and interventional septal reduction therapy success in patients with hypertrophic obstructive cardiomyopathy - a pilot study

Abstract Funding Acknowledgements Type of funding sources: None. Background The mitral valve (MV) has an important contribution to left ventricular outflow tract obstruction (LVOTO) in patients with hypertrophic obstructive cardiomyopathy (HOCM). Several parameters were described to be significantly different between obstructive and non-obstructive forms of HCM, like the aortomitral angle, anterior mitral leaflet (AML) and LVOT size, anterior displacement of the coaptation line, annular related parameters, etc. The redundant length of the AML beyond the coaptation point and the entire AML length are important in the decision to also approach the mitral valve when surgical septal reduction therapy (SRT) is considered, to increase the success rate. Data is scarce regarding mitral valve related predictors of interventional SRT response. This is important as certain patients have a suboptimal response regardless of the proper coronary anatomy and branch targeting. Purpose To evaluate the possible differences in certain mitral valve parameters in interventional SRT responders versus non-responders. Methods We retrospectively included in the study a number of 21 consecutive HOCM patients treated with alcohol septal ablation (ASA). All the procedures were guided with contrast echocardiography besides fluoroscopy and all patients had a proper distribution of at least 1 septal branch. They were divided in two groups- responder group (15 patients) with a non-significant residual LVOT PG (&amp;lt;50mmHg/&amp;gt;50% reduction) and non-responder group (6 patients) with a significant residual LVOT PG (&amp;gt;50mmHg/&amp;lt;50% reduction) and/or early rebound. We accounted for the residual LVOT PG evaluated by continuous Doppler at least 6 months after SRT. The groups were compared regarding LV dimensions and ejection fraction and mitral valve annulus/ leaflet size and displacement of the coaptation line, evaluated by bidimensional transthoracic echocardiography, before the intervention. Results The most hypertrophied part of the LV was the basal interventricular septum (IVS). The two groups were similar regarding age, comorbidities, LV dimensions and ejection fraction and baseline LVOT PG. Also, there was no significant difference between AML length, posterior mitral leaflet (PML) length, AML/PML, MV annulus. The redundant length of the AML was significantly lower in responders whereas anterior displacement of the coaptation point (projection of AML/projection of PML on the MV annulus) was less intense in responders and almost reached statistical significance. (Table) Interestingly, we found a baseline AML/PML projection &amp;lt;1 in all non-responder patients and only in 2 responder patients (13.33%) (p&amp;lt;0.001). Conclusion So far, significant anterior displacement of the coaptation point and the residual AML length may have an important impact on the response to ASA in HOCM patients. This pilot study could be an important start point for larger prospective studies to confirm and evaluated the prediction value of these parameters among others.

Abstract 14476: Automatic Radiomics-Based Assessment of Myocardial Texture in Transthyretin Cardiac Amyloidosis: A 2D Echocardiographic Study

Introduction: Myocardial i nfiltration with amyloid fibrils increases myocardial echogenicity on echocardiography (echo). Increased echogenicity has been challenging to quantify. Radiomics methods may better detect changes in echogenicity than the human eye. Our objectives were (1) to detect an altered myocardial echogenicity in transthyretin cardiac amyloidosis (ATTR-CM) using radiomics analysis and (2) to compare myocardial echogenicity by radiomics to human interpretation. Methods: We evaluated echo images of 515 patients with suspected ATTR-CM referred for an 99m-technetium pyrophosphate scan at 3 major amyloidosis centers. Myocardial echogenicity was assessed at the basal interventricular septum using an open-source radiomics platform (LIFEx) to extract 41 texture-based features. The texture features were processed using a cloud platform (BigML), which performed automated model selection and hyperparameter tuning (Figure). The studies were randomly split into training (80%) and evaluation (20%) sets. Two echo and amyloidosis experts visually evaluated myocardial echogencity on 80 random studies and classified them into ATTR-CM or non- ATTR-CM. Results: In this cohort, 57% of patients were diagnosed with ATTR-CM. The best radiomics model was a decision forest with bootstrapping, with an AUC of 0.79 (95% CI: 0.70-0.88) for diagnosing ATTR-CM. By contrast, visual classification of echo texture as ATTR-CM or not was poor; the interobserver agreement for assessing a septal ROI for altered myocardial echogenicity consistent with ATTR-CM was a kappa of 0.29 and using the entire apical 4 chamber view 0.44. Given the poor agreement an AUC could not be calculated. Conclusions: We have validated the use of a radiomics approach to evaluate myocardial echogenicity in ATTR-CMP. This work lays the foundation to evaluate changes in myocardial texture using echo to raise the suspicion of cardiac amyloidosis and assess changes following targeted TTR therapies.

Late gadolinium enhancement patterns in severe symptomatic high-gradient aortic stenosis

Abstract Background Left ventricular (LV) remodeling in patients with severe aortic valve stenosis (AS) is a complex process that goes beyond hypertrophic response and may involve reparative/replacement fibrosis. Currently, cardiac magnetic resonance (CMR) is the gold-standard imaging technique for detecting focal myocardial fibrosis through late gadolinium enhancement (LGE). However, myocardial fibrosis prevalence and distribution is quite variable among series. Our goal was to assess LGE prevalence and distribution pattern in severe symptomatic high-gradient AS. Methodology Single-center prospective cohort of 132 patients with severe symptomatic high-gradient AS (mean age 73±11 years; 48% male, mean valvular transaortic gradient 60±20 mmHg; mean aortic valve area 0.7±0.2 cm2/m2; mean LV ejection fraction by 2D echocardiogram 58±9%), all with normal flow (except one) undergoing surgical aortic valve replacement. Those with previous history of acute myocardial infarction, ischemic cardiomyopathy or other cardiomyopathy were excluded. All patients performed 1.5T CMR assessment with LV myocardium tissue characterization prior to surgery. Segmental LGE presence was assessed by two independent operators and classified according to the AHA 16 segment model, using 5-standard deviations from remote myocardium as the signal intensity cut-off for LGE identification and quantification. Results Overall, 96 patients (74%) had non-ischemic LGE (median LGE mass 3.2 g [IQR 0.2–8.3] g; median percentage of LGE myocardial mass 2.5% [IQR 0.1–6.1]%); 22 patients [17%] with exclusively junctional LGE); in one patient an incidental ischemic scar (subendocardial distribution) was identified. No cases of subepicardial distribution were found. Intramyocardial LGE was most frequently observed in basal and mid-anterior and inferior interventricular septum – see Figure 1. In these segments, LGE was most often junctional at right-ventricular insertion points (54%), followed by mid-wall LGE (32%) or both sites involvement (14%). Conclusion LGE is frequent in symptomatic high-gradient AS patients with preserved left ventricular ejection fraction, most often presenting as junctional enhancement in basal/mid-anterior and inferior interventricular septum. Future studies may address whether distinct LGE patterns may impact patient prognosis. Funding Acknowledgement Type of funding sources: None.

Recurrences after stereotactic arrhythmia radioablation for refractory ventricular tachycardia

Abstract Introduction Stereotactic arrhythmia radioablation (STAR) has been recently introduced for the management of ventricular tachycardia (VT) refractory to antiarrhythmic drugs (AADs) and catheter ablation (CA). VT recurrences were recently reported after STAR but the mechanisms remain poorly known. Purpose We analyzed VT recurrences after STAR for refractory VT in order to assess the characteristics and delivered dose at sites of VT relapse. Methods From 09.2017 to 01.2020, 12 consecutive patients (pts) (66±8y, LVEF 40±14%) suffering from refractory VT were enrolled. The underlying cardiopathy was ischemic in 3, inflammatory in 3 and idiopathic in 6 pts. Nine (75%) out of 12 pts had a history of at least 1 electrical storm. Before STAR, an invasive electro-anatomical mapping (Carto3) of the VT substrate (VT-sub) was performed. A mean dose of 22±2Gy was delivered to the VT-sub using the Cyberknife® system. Results The ablation volume was 24±7cc and involved the basal interventricular septum (IVS) in 10 (83%) pts. During the first 6 months after STAR, VT burden decreased by 93% (mean value, from 640 to 46 VT/semester). After a median follow-up of 32±11 months, 10/12 (83%) developed ≥1 recurrence as a sustained VT and underwent a redo CA. Two (17%) pts presented 2 distinct VT recurrences from clearly different areas. VT recurrence was located at the border zone (BZ) of the treated VT-sub in 6 (50%) cases, involved both the BZ and a larger substrate in 2 (17%) cases, and occurred remote from the VT-sub in 4 (33%) cases (see Table 1). The dose delivered at sites of VT recurrence was 8.4±8.6 Gy with a large heterogeneity ranging from 0.11 to 28.37 Gy, for some pts due to dose constraints near critical structures (coronary arteries). Voltage mapping showed a small but significant reduction in both unipolar and bipolar EGM voltage in the irradiated area after STAR (before vs after, Bipolar: 1.8±1.2 vs 1.1±1.2 mV and Unipolar: 4.4±2.0 vs 3.4±2.3 mV, p=0.02 and 0.01 respectively). Importantly no pts developed a high-grade AV block after STAR despite IVS irradiation. Conclusion STAR appears to be an efficient tool for the management of refractory VT, leading to a strong VT burden reduction and no new high-grade AV block. Recurrences were nevertheless common, often at the border zone of the irradiated volume. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): CHUV

Specific deformation pattern in hypertensive patients with septal bulge and preserved systolic function.

A wide range of subclinical changes in left ventricular (LV) geometry and function can be observed, even in the early course of arterial hypertension (HTN). Aim of the study was to investigate if the appearance of isolated basal septal hypertrophy (BSH, septal bulge) in asymptomatic young and middle-aged adults with HTN could be a marker of incipient LV systolic dysfunction when other measures of global LV function are still normal. A total of 138 patients with primary arterial hypertension, aged less than 65years, with no comorbidities and with preserved LV ejection fraction (EF) were included. Complete 2D transthoracic echocardiography study was preformed according to standardized protocol, as well as deformation study using speckle tracking echocardiography. Global and regional longitudinal strain was measured in apical 4-, 2- and 3-chamber views according to 18-segments model. Global and regional circumferential and radial strains were measured in short axis view. Average was taken from each of the six basal, middle and apical LV segments. Patients were divided into two groups according to BSH presence and values were compared. Basal septal hypertrophy was found in half of the patients (53.6%). The whole cohort had altogether normal LV global systolic function, as well as global indices of radial strain (GRS 43.86 ± 10.75%) and longitudinal strain (GLS - 19.73 ± 2.19%), while global circumferential strain (GCS) was mildly reduced (GCS - 19.5 ± 2.81%). BSH patients had more expressed LV geometry changes (LV mass: 89.19 ± 24.59g/m2 vs 109.15 ± 25.33g/m2, p < 0.001; relative wall thickness: 0.3 ± 0.08 vs 0.38 ± 0.11, p < 0.001) and also revealed a specific pattern of longitudinal deformation impairment in three LV segments (basal and mid interventricular septum, basal anteroseptum). "Strain gradient" from LV base to apex (basal < mid < apical) was observed in the whole population for longitudinal and circumferential strain, and it was more pronounced in the BSH group. This group had more impaired basal LS, while apical CS was improved. Subendocardial longitudinal strain was also more impaired in the BSH group. This study brings new meaning to basal septal hypertrophy (BSH) occurrence in hypertensive patients with discrete global concentric remodeling. Regional systolic dysfunction of the basal and mid LV segments is found, while apical segments increase in deformation. This specific "strain gradient" pattern was found to be more pronounced in patients with BSH. The recognition of BHS in apparently healthy hypertensive patients with no impairment in global systolic function may suggest latent target organ damage with regional impairment of systolic function and the need to imply more aggressive treatment approach.

Transcatheter Myotomy to Relieve Left Ventricular Outflow Tract Obstruction: The Septal Scoring Along the Midline Endocardium Procedure in Animals.

Left ventricular outflow tract obstruction complicates hypertrophic cardiomyopathy and transcatheter mitral valve replacement. Septal reduction therapies including surgical myectomy and alcohol septal ablation are limited by surgical morbidity or coronary anatomy and high pacemaker rates, respectively. We developed a novel transcatheter procedure, mimicking surgical myotomy, called Septal Scoring Along the Midline Endocardium (SESAME). SESAME was performed in 5 naive pigs and 5 pigs with percutaneous aortic banding-induced left ventricular hypertrophy. Fluoroscopy and intracardiac echocardiography guided the procedures. Coronary guiding catheters and guidewires were used to mechanically enter the basal interventricular septum. Imparting a tip bend to the guidewire enabled intramyocardial navigation with multiple df. The guidewire trajectory determined the geometry of SESAME myotomy. The myocardium was lacerated using transcatheter electrosurgery. Cardiac function and tissue characteristics were assessed by cardiac magnetic resonance at baseline, postprocedure, and at 7- or 30-day follow-up. SESAME myotomy along the intended trajectory was achieved in all animals. The myocardium splayed after laceration, increasing left ventricular outflow tract area (753 to 854 mm2, P=0.008). Two naive pigs developed ventricular septal defects due to excessively deep lacerations in thin baseline septa. No hypertrophy model pig, with increased septal thickness and left ventricular mass compared with naive pigs, developed ventricular septal defects. One animal developed left axis deviation on ECG but no higher conduction block was seen in any animal. Coronary artery branches were intact on angiography with no infarction on cardiac magnetic resonance late gadolinium imaging. Cardiac magnetic resonance chamber volumes, function, flow, and global strain were preserved. No myocardial edema was evident on cardiac magnetic resonance T1 mapping. This preclinical study demonstrated feasibility of SESAME, a novel transcatheter myotomy to relieve left ventricular outflow tract obstruction. This percutaneous procedure using available devices, with a safe surgical precedent, is readily translatable into patients.

Recurrences after stereotactic arrhythmia radioablation for refractory ventricular tachycardia

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Stereotactic arrhythmia radioablation (STAR) has been recently introduced for the management of ventricular tachycardia (VT) refractory to antiarrhythmic drugs and catheter ablation (CA). VT recurrences have been reported after STAR but the mechanisms remain poorly known. We analyzed recurrences in our patients (pts) after STAR for refractory VT. Methods From 09.2017 to 01.2020, 12 pts (66±8y, LVEF 40±14%) suffering from refractory VT were enrolled. The underlying cardiopathy was ischemic in 3, inflammatory in 3 and idiopathic in 6 pts. Nine out of 12 pts had a history of at least 1 electrical storm. Before STAR, an invasive electro-anatomical mapping of the VT substrate (VT-sub) was performed. A mean dose of 22±2Gy was delivered to the VT-sub using the Cyberknife system. Results The ablation volume was 24±7cc and involved the basal interventricular septum (IVS) in 10 pts. During the first 6 months after STAR, VT burden decreased by 95% (mean value, from 930 to 46 VT/semester). After a median follow-up of 14±10 months, 10/12 (83%) developed a recurrence as a sustained VT and underwent a redo CA. VT recurrence was located at the border zone (BZ) of the treated VT-sub in 6 cases, involved both the BZ and a larger substrate in 2 cases, and occurred remote from the VT-sub in 2 cases (see Table). The dose delivered at sites of VT recurrence was 9.9±8.6 Gy with a large heterogeneity ranging from 0.11 to 28.37 Gy, for some patients due to dose constraints near critical structures. Importantly no pts developed an AV block after STAR. Conclusion STAR appears to be an efficient tool for the management of IVS refractory VT, leading to a strong VT burden reduction and no AV block. Recurrences were nevertheless common, often at the border zone of the irradiated volume.

P325 CARDIAC SARCOIDOSIS…TYPICAL CLINICAL PRESENTATION

Abstract We report the case of a 50–year–old man without previous medical hystory who was admitted to our department for recurrent syncopes for several months. Throughout the 24 hours ECG Holter it has been underlined several advanced atrioventricular block episodes, hence the patient underwent to definitive pacemaker implant. After 3 months, due to sustained ventricular tachycardia, the patient incurred a out–of–hospital cardiac arrest; the patient was subjeced to cardio pulmonary resuscitation with the restoration of the sinus rithm following defibrillation. Unfortunatly, due to the resuscitation maneuvers, sternal fracture resulted. During the hospitalization in the Cardiology department, he underwent coronary angiography wich showed non significant lesions. Cardiac Magnetic Resonance was also performed among the tests. The examination was found to be particularly hard to understand due to the presence of the sternal injury that deformed the pectus and affected dynamics of the right ventricle, causing systolic bulging of the subtricuspid region of the right ventricular wall. During the dynamic sequences, there was a mild bi–ventricular reduction in systolic function. In post contrast imaging, extended transmural LGE of the basal interventricular septum and right ventricular wall, as well as multifocal involvement of the left ventricle were found. Examination was not of univolcal interpretation: the patient was tranferred to another Center to perform MR PET wich was found to be strongy suggestive of sarcoidosis, later confirmed by extra cardiac biopsy. For this reason an ICD upgrade was performed along side the immunosoppressive therapy. Sarcoidosis is an inflammatory disease characterized by the presence of noncaseous granulomas in one or more organs or tissues; at the cardiac level it can “mimic” different cardiomyopathies as an insidious diagnosis. The presence of a post–traumatic pectus excavatum leads to dyskinesia of the rignt venticular wall, reduction of the bi–ventricular systolic funcion combine with an extensive late enhancement could suggest arrhytmogenic dysplasia with bi–ventricular involvement. However, by focusing on the clinical presentation (in particular the onset charaterized by unexplained advanced AV block in a young and healthy subjet and subsequent ventricular arrhytmias), through a multimodal and multidisciplinary imaging approach it was posible to diagnose sarcoidosis with cardiac involvement and refer the patient to adequate therapy.

Basal interventricular septum thinning and long-term left ventricular function in patients with sarcoidosis.

Basal interventricular septum (IVS) thinning on transthoracic echocardiography (TTE) is highly specific to cardiac sarcoidosis. Although basal IVS thinning is listed as one of the five major diagnostic criteria for cardiac sarcoidosis, its association with long-term cardiac function has not been investigated. This study aimed to evaluate the epidemiology and clinical relevance of basal IVS thinning in a clinic-based cohort of patients with sarcoidosis. This retrospective observational study was conducted at a general sarcoidosis clinic. The incidence of basal IVS thinning and associations with variables at baseline and a delayed onset of left ventricular (LV) dysfunction (LV ejection fraction [LVEF]<50%) were analyzed. Of the 1009 patients, 23 (2.3%) had basal IVS thinning. Basal IVS thinning was associated with cardiac pacemaker (PM) implantation at baseline (adjusted odds ratio=20.5; 95% confidence interval [CI]=7.9-53.2; P<0.01). Of the 768 patients with an LVEF of ≥50% at baseline who underwent one or more longitudinal TTEs after baseline, 36 (4.7%) developed LV dysfunction over a median observation period of 88.9 months. Basal IVS thinning and PM implantation at baseline were the independent predictors of a delayed onset of LV dysfunction (basal IVS thinning, adjusted hazard ratio [HR]=3.7; 95% CI=1.5-9.6; PM implantation, adjusted HR=15.7; 95% CI=7.4-33.3). Basal IVS thinning in patients with sarcoidosis can predict a delayed onset of LV dysfunction even when the LV function is preserved at the time of detection.

Single-cell transcriptomics provides insights into hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is a genetic heart disease that is characterized by unexplained segmental hypertrophy that is usually most pronounced in the septum. While sarcomeric gene mutations are often the genetic basis for HCM, the mechanistic origin for the heterogeneous remodeling remains largely unknown. A better understanding of the gene networks driving the cardiomyocyte (CM) hypertrophy is required to improve therapeutic strategies. Patients suffering from HCM often receive a septal myectomy surgery to relieve outflow tract obstruction due to hypertrophy. Using single-cell RNA sequencing (scRNA-seq) on septal myectomy samples from patients with HCM, we identify functional links between genes, transcription factors, and cell size relevant for HCM. The data show the utility of using scRNA-seq on the human hypertrophic heart, highlight CM heterogeneity, and provide a wealth of insights into molecular events involved in HCM that can eventually contribute to the development of enhanced therapies.

Inflammatory Cardiomyopathy: A Multi-modality Imaging Approach For A Timely Diagnosis

Non-ischemic cardiomyopathy (NICM) consists of a heterogeneous group of disorders that result from diverse underlying processes - including infectious, autoimmune, infiltrative, genetic, and otherwise idiopathic. We present a case of inflammatory cardiomyopathy diagnosed by multimodal imaging, including cardiac magnetic resonance (CMR) and positron emission scan with 18F-fluorodeoxyglucose (FDG-PET). A 68-year-old Caucasian male with history of hypertension, hyperlipidemia, chronic kidney disease (stage II), and recent diagnoses of NICM and non-sustained ventricular tachycardia 6 months ago presented to our heart failure clinic to be evaluated for advanced heart failure therapies. CMR showed evidence of non-coronary disease late gadolinium enhancement (LGE) in the basal and mid interventricular septum as well as in both papillary muscles. The LGE extent was 14% of the myocardium. Given results of CMR and rising suspicion for sarcoidosis, our patient underwent FDG-PET, which showed persistent inflammation involving 37% of the left ventricle. The patient underwent endomyocardial biopsy (EMB) of both ventricles at a total of 9 sites using electroanatomic voltage mapping which can identify diseased tissues with low voltage signals. The biopsy results showed minimal focal interstitial edema, but no granulomas or active inflammation. Given the degree of active inflammation on FDG-PET the patient was treated with 3 months of oral prednisone. Subsequent FDG-PET demonstrated complete resolution of inflammation in addition to recovery of ejection fraction from 25% to 49%. This case illustrates the role of FDG-PET resulting in a timely diagnosis even when EMB results were inconclusive. Future studies are needed to determine the outcomes of immunosuppression in these patients. Figure 1. CMR demonstrating late gadolinium enhancement (LGE) in the septum, lateral wall, and the papillary muscles. The yellow arrows point to the areas of LGE. Figure 2. FDG-PET image demonstrating significant active inflammation, correlating to SUV (max) = 3.3 involving 37% of the left ventricle. The yellow arrows point to the areas of increased FDG uptake. Non-ischemic cardiomyopathy (NICM) consists of a heterogeneous group of disorders that result from diverse underlying processes - including infectious, autoimmune, infiltrative, genetic, and otherwise idiopathic. We present a case of inflammatory cardiomyopathy diagnosed by multimodal imaging, including cardiac magnetic resonance (CMR) and positron emission scan with 18F-fluorodeoxyglucose (FDG-PET). A 68-year-old Caucasian male with history of hypertension, hyperlipidemia, chronic kidney disease (stage II), and recent diagnoses of NICM and non-sustained ventricular tachycardia 6 months ago presented to our heart failure clinic to be evaluated for advanced heart failure therapies. CMR showed evidence of non-coronary disease late gadolinium enhancement (LGE) in the basal and mid interventricular septum as well as in both papillary muscles. The LGE extent was 14% of the myocardium. Given results of CMR and rising suspicion for sarcoidosis, our patient underwent FDG-PET, which showed persistent inflammation involving 37% of the left ventricle. The patient underwent endomyocardial biopsy (EMB) of both ventricles at a total of 9 sites using electroanatomic voltage mapping which can identify diseased tissues with low voltage signals. The biopsy results showed minimal focal interstitial edema, but no granulomas or active inflammation. Given the degree of active inflammation on FDG-PET the patient was treated with 3 months of oral prednisone. Subsequent FDG-PET demonstrated complete resolution of inflammation in addition to recovery of ejection fraction from 25% to 49%. This case illustrates the role of FDG-PET resulting in a timely diagnosis even when EMB results were inconclusive. Future studies are needed to determine the outcomes of immunosuppression in these patients. Figure 1. CMR demonstrating late gadolinium enhancement (LGE) in the septum, lateral wall, and the papillary muscles. The yellow arrows point to the areas of LGE. Figure 2. FDG-PET image demonstrating significant active inflammation, correlating to SUV (max) = 3.3 involving 37% of the left ventricle. The yellow arrows point to the areas of increased FDG uptake.

Comparison of sites of wall thickening and abnormal late enhancement on cardiac CT and magnetic resonance imaging with electrocardiography findings in patients with confirmed cardiac amyloidosis

Abstract Funding Acknowledgements Type of funding sources: None. Background Left ventricular (LV) wall thickening and diastolic dysfunction on a transthoracic echocardiogram (TTE) without a high voltage R wave on V5 leads on an ECG leads to a diagnosis of cardiac amyloidosis. A final diagnosis is made by endomyocardial biopsy. However, amyloid sometimes invades the right ventricle (RV), and left (LA) and right (RA) atria, causing ECG changes such as sick sinus syndrome (SSS), arrhythmia, and QRS wave axis deviation. Purpose To elucidate the relationship between sites of wall thickening and abnormal late enhancement (LE) on cardiac computed tomography (CT) and magnetic resonance imaging (MRI), suggesting amyloid invasion, with ECG findings in patients with cardiac amyloidosis confirmed by biopsy. Methods A total of 26 patients (11 females) with suspected cardiac amyloidosis, who had LV wall thickening by TTE without a high voltage R wave in V5 leads on ECG, underwent cardiac CT. LV wall thickening observed on CT in the early phase led to a late phase acquisition. Five patients (3 females, mean age 73 years) were diagnosed with cardiac amyloidosis: complicated multiple myeloma, 2; senile ATTR (transthyretin) amyloidosis, 1; immunoglobulin light chain (AL) amyloidosis, 1; and transthyretin mutation, 1. Four patients underwent cardiac MRI. Results Case 1 had wall thickening in the basal interventricular septum (IVS), LV inferior-posterior wall, LA on CT, abnormal LE in the endocardium in whole LV, RV, and RA on CT, and LE in the endocardium in whole LV, RV, LA, and IVS on MRI. ECG showed SSS (junctional rhythm), left axis QRS wave deviation, no low voltage R wave in limb leads, and a mild LA load. Case 2 had wall thickening in whole LV, RV, LA, and IVS on CT, and unclear (CT) or no (MRI) abnormal LE. ECG revealed SSS (junctional rhythm), a normal QRS axis, no low voltage R wave in limb leads, and no LA load. Case 3 had wall thickening in the LA and basal IVS on CT, abnormal LE in the LA and basal IVS on CT, and LE in the LA only on MRI. ECG revealed atrial tachycardia, a normal QRS axis with low voltage R wave in limb leads, and no LA load. Case 4 had wall thickening in the LA, an RV moderator band on CT, an unclear LE on CT, and LE in whole LV, endocardium in the RV, and whole IVS on MRI. ECG showed a normal sinus rhythm, left axis QRS wave deviation, with low voltage R wave in limb leads, and no LA load. Case 5 had wall thickening in the IVS, LV lateral wall, LV anterior wall, RA, RV outflow tract, and RA appendage, and no abnormal LE on CT (MRI not performed). ECG revealed a normal sinus rhythm, right axis QRS wave deviation, with low voltage R wave in limb leads, and a mild LA load. Conclusions In this pilot study of a small number of patients with cardiac amyloidosis, few relationships between sites of wall thickening and abnormal LE on ECG were found. However, a long-term follow-up study with more patients may reveal relationships between such parameters using this methodology. Abstract Figure. Classification by wall thickening on CT

Septal myectomy with mitral valve surgery in patients after alcohol septal ablation.

OBJECTIVESWe studied 16 patients after failed alcohol septal ablation who underwent extended septal myectomy to analyse the results of surgical correction and identify technical pitfalls the surgeons may be confronted by.METHODSBetween October 2017 and March 2019, 16 patients underwent surgical extended septal myectomy with accompanying anomalous secondary chordae resection, papillary muscles mobilization [in 9 (56.3%) patients], and anterior mitral leaflet plication after previously failed alcohol septal ablation. Routine preoperative computed tomography or cardiac magnetic resonance planning and intraoperative transoesophageal echocardiography were performed in each of the studied patients. Major technical features were identified and complemented during septal myectomy of the calcified interventricular septum.RESULTSThe mean age of the studied patients accounted 50.5 ± 14.6, median—54; males—5 (31.3%). Mean cross-clamp time accounted 52 ± 7.2 min. Calcified basal interventricular septum was identified in 2 (12.5%) patients. No iatrogenic ventricular septal defect (0%) was made during surgical correction. Peak systolic pressure gradient decreased from 86 (interquartile range: 75–104.7) to 20 (16–22) mmHg (P< 0.001). No patients with moderate or severe mitral regurgitation were identified, whereas before the procedure, the number of those accounted 13 (81.2%) individuals. In-hospital and overall mortality after septal myectomy accounted 0%.CONCLUSIONSExtended septal myectomy in patients who previously underwent alcohol septal ablation is a safe procedure that affects all pathological manifestations of the disease. Routine preoperative computed tomography or cardiac magnetic resonance provides detailed anatomy of the anomalous left ventricle and subvalvular structures and allows to measure the extension of myectomy preventing the occurrence of iatrogenic ventricular septal defect. Septal myectomy of the calcified interventricular septum requires avoidance of ‘one-piece technique’ since fragmental myectomy allows visually control the adequacy of the left ventricle outflow tract release.