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Hypertrophic cardiomyopathy (HCM) remains the most common cardiomyopathy in humans and cats with few preclinical pharmacologic interventional studies. Small-molecule sarcomere inhibitors are promising novel therapeutics for the management of obstructive HCM (oHCM) patients and have shown efficacy in left ventricular outflow tract obstruction (LVOTO) relief. The objective of this study was to explore the 6-, 24-, and 48-hour (h) pharmacodynamic effects of the cardiac myosin inhibitor, CK-586, in six purpose-bred cats with naturally occurring oHCM. A blinded, randomized, five-treatment group, crossover preclinical trial was conducted to assess the pharmacodynamic effects of CK-586 in this oHCM model. Dose assessments and select echocardiographic variables were assessed five times over a 48-h period. Treatment with oral CK-586 safely ameliorated LVOTO in oHCM cats. CK-586 treatment dose-dependently eliminated obstruction (reduced LVOTOmaxPG), increased measures of systolic chamber size (LVIDs Sx), and decreased select measures of heart function (LV FS% and LV EF%) in the absence of impact on heart rate. At all tested doses, a single oral CK-586 dose resulted in improved or resolved LVOTO with well-tolerated, dose-dependent, reductions in LV systolic function. The results from this study pave the way for the potential use of CK-586 in both the veterinary and human clinical setting.

Background: Patients with hypertrophic obstructive cardiomyopathy (HOCM) have few available nonsurgical treatment options. The feasibility of CARTOSound-guided catheter radiofrequency ablation (RFA) has been reported previously; however, relevant data are limited. The objective is to retrospectively evaluate the effectiveness and safety of CARTOSound-guided RFA for patients with HOCM. Methods: Thirty-seven patients with successive HOCM accompanied by severe left ventricular outflow tract (LVOT) obstruction underwent CARTOSound-guided RFA were reviewed. The intracardiac echocardiography (ICE) images obtained were merged with the CARTO system to create a shell of the left ventricle. The systolic anterior motion-septal contact area marked from the ICE images was considered the target area for the current delivery of RFA. Follow-up data of the LVOT gradient examined before, 1 month, 6 months, 1 year, and every year after catheter-mediated RFA were accessed. Results: The symptoms of 30 patients (81.1%) improved during the follow-up after RFA. The symptoms of all 30 patients were alleviated from the New York Heart Association (NYHA) class IV/III/II to the NYHA class II/I. A sustained and significant gradient reduction was observed in 28 patients (75.7%). The invasive pressure gradient of LVOT was 84.43 ± 27.55 mm Hg before RFA and 42.78 ± 36.38 mm Hg after RFA (P < .001), with a decrease of 41.65 ± 19.72 mm Hg. The median drop in pressure gradient was 36.0% (1.0-67.0%). Conclusions: Catheter-mediated RFA is an effective and safe treatment for patients with HOCM. However, its long-term efficacy and safety should be validated in the future by conducting multicenter clinical trials with large sample sizes. [ABSTRACT FROM AUTHOR]

Background: Transcatheter mitral valve replacement (TMVR) has emerged as a minimally invasive alternative to mitral valve surgery for patients at high or prohibitive operative risk. Prospective studies reported favourable outcomes in patients with annulus calcification (valve-in-mitral annulus calcification; ViMAC), failed annuloplasty ring (mitral valve-in-ring; MViR), and bioprosthetic mitral valve dysfunction (mitral valve-in-valve; MViV). Multi-slice computed tomography (MSCT)-derived 3D-modelling and simulations may provide complementary anatomical perspectives for TMVR planning. Aims: We aimed to illustrate the implementation of MSCT-derived modelling and simulations in the workup of TMVR for ViMAC, MViR, and MViV. Methods: For this retrospective study, we included all consecutive patients screened for TMVR and compared MSCT data, echocardiographic outcomes and clinical outcomes. Results: Sixteen out of 41 patients were treated with TMVR (ViMAC n = 9, MViR n = 3, MViV n = 4). Eleven patients were excluded for inappropriate sizing, 4 for anchoring issues and 10 for an unacceptable risk of left ventricular outflow tract obstruction (LVOTO) based on 3D modelling. There were 3 procedure-related deaths and 1 non-procedure-related cardiovascular death during 30 days of follow-up. LVOTO occurred in 3 ViMAC patients and 1 MViR patient, due to deeper valve implantation than planned in 3 patients, and anterior mitral leaflet displacement with recurrent basal septum thickening in 1 patient. TMVR significantly reduced mitral mean gradients as compared with baseline measurements (median mean gradient 9.5 (9.0–11.5) mm Hg before TMVR versus 5.0 (4.5–6.0) mm Hg after TMVR, p = 0.03). There was no residual mitral regurgitation at 30 days. Conclusion: MSCT-derived 3D modelling and simulation provide valuable anatomical insights for TMVR with transcatheter balloon expandable valves in ViMAC, MViR and MViV. Further planning iterations should target the persistent risk for neo-LVOTO. [ABSTRACT FROM AUTHOR]

Simple Summary: In recent years, intraventricular pressure gradient (IVPG) measured using color M-mode, which is excellent for evaluating diastolic function, has gained attention. In this study, the IVPG of cats with hypertrophic cardiomyopathy (HCM) was evaluated. The results showed that in non-obstructive HCM (HNCM), there were no changes in IVPG, whereas in hypertrophic obstructive cardiomyopathy (HOCM), IVPG increased despite a suspected decline in diastolic function. The fact that a significant difference was observed only with IVPG suggests the existence of pathophysiological differences that can only be detected by IVPG. By using IVPG for the evaluation of HOCM, it is expected that more accurate assessment of the condition, improvement of treatment methods, and new prognostic indicators, which were previously unattainable, will become possible. Hypertrophic cardiomyopathy (HCM) is a common form of cardiomyopathy in cats, and heart failure occurs as diastolic dysfunction progresses. HCM in cats is broadly classified as non-obstructive and obstructive hypertrophic cardiomyopathy, depending on the presence or absence of outflow tract obstruction. Measurement of the intraventricular pressure differences (IVPD) using color M-mode (CMM) has attracted attention as a reliable diastolic index as it correlates with catheterization, the gold standard for the assessment of diastolic performance. Because IVPD is affected by the size of the heart, the intraventricular pressure gradient (IVPG) index, which is unaffected by heart size, is by calculated by dividing IVPD by LV length. In the present study, CMM IVPG was used to non-invasively assess diastolic impairment in cats with obstructive hypertrophic cardiomyopathy. This study was conducted on 10 control cats and 18 cats in the HCM group. Although no severe left atrial enlargement was observed in the HCM group, the basal IVPG was significantly increased in the HOCM group compared to the control group. Although IVPD typically suggests impaired diastolic function and reduced ventricular compliance, the significant increase observed in the HOCM group compared to controls may suggest an indirect elevation in left atrial pressure, likely secondary to left ventricular outflow tract obstruction. The increase in IVPG in HOCM, as shown in this study, is a pathological effect of left ventricular outflow tract obstruction that cannot be detected by conventional echocardiographic indices, and evaluating IVPG is useful to evaluate cardiac function from a perspective that differs from conventional methods. [ABSTRACT FROM AUTHOR]

Introduction: 5p deletion syndrome, also called Cri-du-chat syndrome 5p is a rare genetic syndrome with reports up to 36% of patients are associated with congenital heart defects. We investigated the association between left outflow tract obstruction and Cri-du-chat syndrome. Methods: A retrospective review of the abnormal microarray cases with congenital heart defects in Children's Hospital of Pittsburgh and the Cytogenomics of Cardiovascular Malformations Consortium. Results: A retrospective review at nine pediatric centers identified 4 patients with 5p deletions and left outflow tract obstruction (LVOTO). Three of these patients had additional copy number variants. We present data suggesting an association of LVOTO with 5p deletion with high mortality in the presence of additional copy number variants. Conclusion: A rare combination of 5p deletion and left ventricular outflow obstruction was observed in the registry of copy number variants and congenital heart defects. [ABSTRACT FROM AUTHOR]

Summary: Hypertrophic cardiomyopathy (HCM) is the most common inherited heart disease that is characterized by left ventricular hypertrophy unexplained by secondary causes. Based on international epidemiological data, around 20,000–40,000 patients are expected to be affected in Austria. Due to the wide variety of clinical and morphological manifestations the diagnosis can be difficult and the disease therefore often goes unrecognized. HCM is associated with a substantial reduction in quality of life and can lead to sudden cardiac death, especially in younger patients. Early and correct diagnosis, including genetic testing, is essential for comprehensive counselling of patients and their families and for effective treatment. The latter is especially true as an effective treatment of outflow tract obstruction has recently become available in the form of a first in class cardiac myosin ATPase inhibitor, as a noninvasive alternative to established septal reduction therapies. The aim of this Austrian consensus statement is to summarize the recommendations of international guidelines with respect to the genetic background, pathophysiology, diagnostics and management in the context of the Austrian healthcare system and resources, and to present them in easy to understand algorithms. [ABSTRACT FROM AUTHOR]

New postprocessing software facilitates 3-dimensional (3D) echocardiographic determination of mitral annular (MA) and neo–left ventricular outflow tract (neo-LVOT) dimensions in patients undergoing transcatheter mitral valve replacement (TMVR). This study aims to test the accuracy of 3D echocardiographic analysis as compared to baseline computed tomography (CT). A total of 105 consecutive patients who underwent TMVR at 2 tertiary care centers between October 2017 and May 2023 were retrospectively included. A virtual valve was projected in both baseline CT and 3D transesophageal echocardiography (TEE) using dedicated software. MA dimensions were measured in baseline images and neo-LVOT dimensions were measured in baseline and postprocedural images. All measurements were compared to baseline CT as a reference. The predicted neo-LVOT area was correlated with postprocedural peak LVOT gradients. There was no significant bias in baseline neo-LVOT prediction between both imaging modalities. TEE significantly underestimated MA area, perimeter, and medial-lateral dimension compared to CT. Both modalities significantly underestimated the actual neo-LVOT area (mean bias pre/post TEE: 25.6 mm2, limit of agreement: −92.2 mm2 to 143.3 mm2; P < 0.001; mean bias pre/post CT: 28.3 mm2, limit of agreement: −65.8 mm2 to 122.4 mm2; P = 0.046), driven by neo-LVOT underestimation in the group treated with dedicated mitral valve bioprosthesis. Both CT- and TEE-predicted-neo-LVOT areas exhibited an inverse correlation with postprocedural LVOT gradients (r2 = 0.481; P < 0.001 for TEE and r2 = 0.401; P < 0.001 for CT). TEE-derived analysis provides comparable results with CT-derived metrics in predicting the neo-LVOT area and peak gradient after TMVR. [Display omitted] [ABSTRACT FROM AUTHOR]

Takotsubo syndrome (TTS) can mimic acute coronary syndrome despite being a distinct disease. While typically benign, TTS can lead to serious complications like cardiogenic shock. Cardiogenic shock occurs in 1–20% of TTS cases. Various mechanisms can cause shock, including pump failure, right ventricular involvement, left ventricular outflow tract obstruction, and acute mitral regurgitation. Because treatment depends on the mechanism, early identification of the mechanism developing cardiogenic shock is essential for optimal treatment and improved outcomes in TTS patients with cardiogenic shock. This review summarizes current knowledge on causes and treatment of cardiogenic shock in patients with TTS. [ABSTRACT FROM AUTHOR]

Left ventricular septal myotomy provides a favorable prognosis for children with hypertrophic obstructive cardiomyopathy (HOCM). However, some children still suffer from recurrent left ventricular outflow tract obstruction (LVOTO) after surgery. Poor prognosis exists for HOCM caused by PTPN11 mutation. Therefore, the aim of this study was to determine the clinical features of recurrent obstruction in children with HOCM caused by pathogenic mutations in the PTPN11 gene. Fifty-six children who were diagnosed with HOCM underwent septal myectomies. Whole-exome sequencing of 49 pediatric cardiomyopathy–associated genes (including PTPN11) was performed. We performed hematoxylin-eosin, Masson, and wheat germ agglutinin staining of those tissues positive and negative for PTPN11. Whole-exome sequencing results showed 11 children with the PTPN11 mutation (19.6%). In long-term follow-up (median 37 months, maximum 9 years), children with the PTPN11 mutation had 6 (54.5%) recurrent LVOTOs compared with other groups (P =.015) but similar survival rates (P =.514). The mean postoperative time to recurrent obstruction was 22 ± 7 months. Children with PTPN11 mutation were 9-fold more likely to experience the risk associated with recurrent obstruction (95% confidence interval, 1.77-45.81, P <.001). Hematoxylin-eosin, Masson, and wheat germ agglutinin staining also revealed more cardiomyocyte hypertrophy in tissues with the PTPN11 mutation. Children with PTPN11 mutation–associated hypertrophic cardiomyopathy have a greater risk of recurrent LVOTO. [Display omitted] [ABSTRACT FROM AUTHOR]

Hypertrophic cardiomyopathy is a prevalent cause of sudden cardiac death among young people. This distinctive genetic condition can manifest at any age from infancy to adulthood. The primary features include unexplained left ventricular hypertrophy coupled with dynamic left ventricular outflow tract (LVOT) obstruction and a variable degree of mitral valve regurgitation. In certain cases, patients may also experience biventricular outflow tract obstruction. Surgical septal myectomy is the gold standard treatment for symptomatic children experiencing severe LVOT obstruction. This review focuses on surgical techniques for septal myectomy in pediatric patients and other adjunct procedures and summarizes the current outcomes.

Hypertrophic cardiomyopathy (HCM) is a common disorder characterized by unexplained left ventricular hypertrophy. The disease can have different phenotypic expressions and can be genetic in nature with autosomal dominant inheritance. It usually runs a benign course in the majority but can lead to heart failure, atrial fibrillation, and sudden cardiac death (SCD). Echocardiography plays a key role in the diagnosis and overall management of the condition. It is useful in diagnosis, differentiation of different types (obstructive vs nonobstructive), in systematic evaluation of associated abnormalities (like mitral regurgitation), helps in selection of appropriate treatment and is helpful in guiding the intervention procedures for the condition. Certain echocardiographic measures are predictors of SCD. The review describes in detail the techniques and nuances of performing a comprehensive echocardiographic evaluation of patients with HCM.

Background Although Takotsubo syndrome (TTS) is generally considered a benign disease, recent reports showed the incidence of cardiogenic shock due to left ventricular outflow tract obstruction (LVOTO), mitral regurgitation (MR), and primary pump failure was estimated to be 6–20%. Case summary A 78-year-old woman presented with chest pain and cold sweats 2 days after surgery for lung cancer. Acute coronary syndrome was suspected based on her symptoms, electrocardiography, transthoracic echocardiography (TTE), and laboratory data; thus, emergency catheterization was performed. Normal coronaries were observed, with hyperkinesis at the base of the left ventricle and akinesis at its apex, leading to the diagnosis of the apical ballooning type of TTS. Pressure differences between the apex of the left ventricle (168/8/28 mmHg) and aorta (94/50/64 mmHg) indicated the presence of LVOTO. Two days after TTS onset, she developed cardiogenic shock (blood pressure was 54/38 mmHg). Transthoracic echocardiography showed acute MR due to systolic anterior motion of the mitral valve caused by LVOTO, which was further exacerbated by paroxysmal atrial fibrillation. Fluid resuscitation, intravenous β-blockers, and amiodarone were administered for reduction of the pressure gradient in the left ventricular outflow, rate control, and sinus rhythm maintenance. Her condition improved along with the MR, thereby improving LVOTO and maintaining sinus rhythm. Discussion Takotsubo syndrome should be kept in mind as a potential cause of acute MR due to LVOTO. Catheterization and multiple follow-up TTE play a major role in early detection for this condition. [ABSTRACT FROM AUTHOR]

Background We report endocardial radiofrequency (RF) ablation as an alternative treatment approach for a symptomatic patient with obstructive hypertrophic cardiomyopathy (oHCM), who is not suitable for surgical septal myectomy or alcohol septal ablation. Endocardial RF ablation, with detailed 3D mapping of the intrinsic conducting system, offers the possibility of reducing the risk of complete heart block rates and of effectively relieving symptoms. Case summary We present a symptomatic 51-year-old female patient with oHCM and a maximum left ventricular outflow tract (LVOT) gradient of 148 mmHg. Because of alcohol septal ablation failure, endocardial RF ablation in combination with detailed mapping of the intrinsic conduction system and intraprocedural imaging was performed. The 6-month follow-up showed a significant improvement in exercise tolerance, no relevant dynamic LVOT obstruction with a gradient of 22 mmHg under Valsalva. Discussion In the current case report, endocardial RF ablation persistently reduced LVOT gradients in a patient with oHCM. Pre-interventional imaging, detailed 3D mapping of the conduction system, and correlation to intracardiac and transthoracic echocardiography were key for an effective and safe ablation of a small target zone. [ABSTRACT FROM AUTHOR]

Hypertrophic cardiomyopathy is a prevalent cause of sudden cardiac death among young people. This distinctive genetic condition can manifest at any age from infancy to adulthood. The primary features include unexplained left ventricular hypertrophy coupled with dynamic left ventricular outflow tract (LVOT) obstruction and a variable degree of mitral valve regurgitation. In certain cases, patients may also experience biventricular outflow tract obstruction. Surgical septal myectomy is the gold standard treatment for symptomatic children experiencing severe LVOT obstruction. This review focuses on surgical techniques for septal myectomy in pediatric patients and other adjunct procedures and summarizes the current outcomes. Keywords:Hypertrophic cardiomyopathy, sudden cardiac death, left ventricular outflow tract obstruction, asymmetrical septal hypertrophy, left ventricular myectomy: [ABSTRACT FROM AUTHOR]

Introduction5p deletion syndrome, also called Cri-du-chat syndrome 5p is a rare genetic syndrome with reports up to 36% of patients are associated with congenital heart defects. We investigated the association between left outflow tract obstruction and Cri-du-chat syndrome.MethodsA retrospective review of the abnormal microarray cases with congenital heart defects in Children’s Hospital of Pittsburgh and the Cytogenomics of Cardiovascular Malformations Consortium.ResultsA retrospective review at nine pediatric centers identified 4 patients with 5p deletions and left outflow tract obstruction (LVOTO). Three of these patients had additional copy number variants. We present data suggesting an association of LVOTO with 5p deletion with high mortality in the presence of additional copy number variants.ConclusionA rare combination of 5p deletion and left ventricular outflow obstruction was observed in the registry of copy number variants and congenital heart defects.

Transatrial transcatheter mitral valve replacement is a hybrid strategy involving placing the patient on cardiopulmonary bypass and direct implantation of a transcatheter valve in a calcified annulus for mitral annular calcification. We report a rare phenomenon of systolic anterior motion of the leaflets of a transcatheter heart valve prosthesis used for mitral valve replacement causing left ventricular outflow tract obstruction. Although reported in transcatheter mitral valve replacement, we believe this is the first report of left ventricular outflow tract obstruction after transatrial mitral valve replacement and discuss the pre-disposing risk factors. [ABSTRACT FROM AUTHOR]

The "2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy" provides recommendations to guide clinicians in the management of patients with hypertrophic cardiomyopathy. A comprehensive literature search was conducted from September 14, 2022, to November 22, 2022, encompassing studies, reviews, and other evidence on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through May 23, 2023, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate. Hypertrophic cardiomyopathy remains a common genetic heart disease reported in populations globally. Recommendations from the "2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy" have been updated with new evidence to guide clinicians. [ABSTRACT FROM AUTHOR]

AIM: The "2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy" provides recommendations to guide clinicians in the management of patients with hypertrophic cardiomyopathy. METHODS: A comprehensive literature search was conducted from September 14, 2022, to November 22, 2022, encompassing studies, reviews, and other evidence on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, the Agency for Healthcare Research and Quality, and other selected databases relevant to this guideline. Additional relevant studies, published through May 23, 2023, during the guideline writing process, were also considered by the writing committee and added to the evidence tables, where appropriate. STRUCTURE: Hypertrophic cardiomyopathy remains a common genetic heart disease reported in populations globally. Recommendations from the "2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy" have been updated with new evidence to guide clinicians. [ABSTRACT FROM AUTHOR]

OBJECTIVES Left ventricular outflow tract obstruction (LVOTO) is a major cause of morbidity and mortality in infants with interrupted aortic arch (IAA). Left Ventricular Outflow Tract (LVOT) development may be flow-mediated, thus IAA morphology may influence LVOT diameter and subsequent reintervention. We investigated the association of IAA morphology [type and presence of aortic arch aberrancy (AAb)] with LVOT diameter and reintervention. METHODS All surgical patients with IAA (2001–2022) were reviewed at a single institution. We compared IAA-A versus IAA-B; IAA with aortic AAb versus none; IAA-B with aberrant subclavian (AAbS) artery versus others. Primary outcomes included LVOT diameter (mm), LVOTO at discharge (≥50 mmHg), and LVOT reintervention. RESULTS Seventy-seven infants (mean age 10 ± 19 days) were followed for 7.6 (5.5–9.7) years. Perioperative mortality was 3.9% (3/77) and long-term mortality was 5.2% (4/77). Out of 51 IAA-B (66%) and 22 IAA-A (31%) patients, 30% (n  = 22) had AAb. Smaller LVOT diameter was associated with IAA-B [IAA-A: 5.40 (4.68–5.80), IAA-B: 4.60 (3.92–5.50), P  = 0.007], AAb [AAb: 4.00 (3.70–5.04) versus none: 5.15 (4.30–5.68), P  = 0.006], and combined IAA-B + AAbS [IAA-B + AAbS: 4.00 (3.70–5.02) versus other: 5.00 (4.30–5.68), P  = 0.002]. The likelihood of LVOTO was higher among AAb [ N  = 6 (25%) vs N  = 1 (2%), P  = 0.004] and IAA-B + AAbS [ N  = 1 (2%) vs N  = 6 (30%), P  = 0.002]. Time-to-event analysis showed a signal towards increased LVOT reintervention in IAA-B + AAbS (P  = 0.11). CONCLUSIONS IAA-B and AAb are associated with small LVOT diameter and early LVOTO, especially in combination. This may reflect lower flow in the proximal arch during development. Most reinterventions occur in IAA-B + AAbS, hence these patients should be carefully considered for LVOT intervention at the time of initial repair. [ABSTRACT FROM AUTHOR]

Background Hypertrophic cardiomyopathy (HCM) is a genetic heart disease that can lead to heart failure, atrial fibrillation, and ischaemic symptoms. Managing patients with HCM and ischaemic symptoms is challenging, and several treatment options have been proposed. Case summary A 30-year-old male patient presented with severe chest pain that had been ongoing for more than 30 min at rest. He was diagnosed with HCM and had periodic chest pain since the age of 14. He underwent two separate ethyl alcohol ablations of the first septal branches of the left anterior descending and posterior descending arteries, which relieved his symptoms. Discussion This case report highlights the challenges in managing patients with HCM and ischaemic symptoms. In this patient, the use of ethyl alcohol ablation was effective in reducing left ventricular outflow tract obstruction and improving symptoms. Ethyl alcohol ablation is a minimally invasive procedure that has been shown to be effective in symptomatic patients with HCM. Overall, this case report emphasizes the importance of individualized treatment for patients with HCM and the potential benefits of alcohol ablation in this population. [ABSTRACT FROM AUTHOR]

Left ventricular outflow tract (LVOT) obstruction is a life-threatening complication of transcatheter mitral valve replacement. In-depth analysis of pre-procedural computed tomography enables accurate prediction of this risk. Several techniques for LVOT modification, including Laceration of the Anterior Mitral leaflet to Prevent Outflow ObtructioN, preemptive alcohol septal ablation, preemptive radiofrequency ablation, and Septal Scoring Along the Midline Endocardium, have been described as effective strategies to mitigate this risk. This review aims to explore the indications, procedural steps, and outcomes associated with these LVOT modification techniques. [ABSTRACT FROM AUTHOR]

Mitral valve dysfunction is prevalent amongst older patients. Of those not suitable for surgical therapy, mitral transcatheter edge-to-edge repair (TEER) can treat as large proportion of patients, many are not suitable TEER candidates. As such, orthotopic transcatheter mitral valve replacement (TMVR) is an important innovation but it faces significant challenges. Orthotopic TMVR requires a prosthesis with stable anchoring, adequate sealing, minimal footprint in the left ventricle and long term durability. Multidisciplinary expertise in advanced imaging, surgery, heart failure are needed for success. [ABSTRACT FROM AUTHOR]

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The intricate interplay between mitral regurgitation (MR) and left ventricular outflow tract (LVOT) obstruction may result in two clinical scenarios: prosthesis-related LVOT obstruction after mitral valve replacement (TMVR) and systolic anterior motion (SAM)-associated MR. This review provides a comprehensive overview of the pathophysiology, risk assessment, and transcatheter interventions for mitigating the likelihood of LVOT obstruction in patients undergoing TMVR. In addition, it extends its focus to SAM-associated MR, elucidating the different aetiological mechanisms contributing to this phenomenon, beyond hypertrophic cardiomyopathy. Transcatheter treatment options, are explored as potential therapeutic strategies, offering insights into their hemodynamic effectiveness and limitations. [ABSTRACT FROM AUTHOR]

An 83-year-old woman was admitted to our center because of heart failure. Transthoracic echocardiography revealed severe mitral annular calcification resulting in a double mitral valve lesion. After discussion by the heart team, transcatheter mitral valve replacement with Tendyne (Abbott Structural, Santa Clara, CA, USA) was performed. Despite having a predicted neo-left ventricular outflow tract (LVOT) above the cut-off value, the patient developed clinically significant LVOT obstruction (LVOTO) refractory to medical treatment. This situation is often treated before the intervention, and dealing with LVOTO afterward can be challenging. After taking the patient's anatomy into consideration, we decided to perform alcohol septal ablation. Applying a combined strategy of medical treatment and intervention led to success. In this case report, we discuss this event and the strategies available for preventing and managing the condition.

Severe left ventricular outflow tract obstruction (LVOTO) of hypertrophic cardiomyopathy is an acutely life-threatening, must-not miss, cardiology emergency that infrequently presents to the emergency department (ED). Patients with this condition usually manifest chest pain, syncope, cardiogenic shock, and severe ischemia. LVOTO is easy misdiagnosed as acute coronary syndrome. In our patient, the ECG showed a significant ST-segment depression and a 0/0 mmHg blood pressure when the peak left ventricular outflow tract gradient was abruptly increased by provocable activities. However, the patient had normal coronaries on cardiac catheterization, and, upon being immediately treated with intravenous esmolol, his symptoms were relieved and blood pressure was normal after 30 minutes. This case highlights, not only that early and exact diagnosis of LVOTO is crucial, but also the importance of the therapeutic strategies used.

BackgroundAortic stenosis (AS) in combination with left ventricular outflow tract obstruction (LVOTO) has occasionally been reported. However, making a precise diagnosis and successfully treating this combination is challenging due to the hemodynamic interaction between the two conditions.Case summaryA 56-year-old male patient who had been diagnosed with severe AS and asymmetric left ventricular hypertrophy underwent aortic valve replacement (AVR) and a conventional septal myectomy. Immediately after the procedure, significant systolic anterior motion and mitral regurgitation developed, necessitating a surgical mitral edge-to-edge repair. Ten days after the procedure, the patient developed hematuria and LVOTO, which was confirmed by echocardiography. Because the LVOTO might have been the cause of the hematuria, the patient underwent alcohol septal ablation, but this had little effect. Three months later, a transapical beating-heart septal myectomy (TA-BSM) was performed in our hospital. Postoperatively, the LVOTO had been significantly ameliorated and the hematuria had resolved.ConclusionFor patients with AS and LVOTO due to a hypertrophic interventricular septum, inadequate amelioration of the LVOTO after AVR may lead to severe hemolytic hematuria. TA-BSM is a minimally invasive, safe, and effective surgical procedure for ameliorating LVOTO in patients with aortic valve prostheses.

Background: Cardiac myxomas are benign tumors that can occur in any heart chamber or valve. They are extremely rare in dogs. We present a novel case involving a cardiac myxoma in the left ventricular outflow tract (LVOT) and a ventricular septal defect (VSD) in a small dog. Case Description: A female miniature dachshund (age, 7 months; weight, 2.88 kg) presented with growth insufficiency, lethargy, and a cardiac murmur. Echocardiography revealed a small polypoid mass in the LVOT and a membranous VSD. Simultaneous surgeries were performed to resect the mass (aortotomy) and close the VSD (right atriotomy) using low-flow cardiopulmonary bypass with surface-cooling hypothermia and retrograde cardioplegia. The tumor was histopathologically identified as a myxoma. The dog survived with no cardiac complications for 11 years after surgery. Conclusion: To our knowledge, this is the first report of ante-mortem diagnosis and simultaneous surgical repair of a cardiac myxoma obstructing the LVOT and a VSD in a small-breed dog. In addition to describing this complicated case, this report presents what we believe is the first reported use of retrograde cardioplegia during open-heart surgery in a small-breed dog. [Open Vet J 2024; 14(2.000): 743-749]

Hypertrophic cardiomyopathy (HCM) is a common form of cardiomyopathy in cats, and heart failure occurs as diastolic dysfunction progresses. HCM in cats is broadly classified as non-obstructive and obstructive hypertrophic cardiomyopathy, depending on the presence or absence of outflow tract obstruction. Measurement of the intraventricular pressure differences (IVPD) using color M-mode (CMM) has attracted attention as a reliable diastolic index as it correlates with catheterization, the gold standard for the assessment of diastolic performance. Because IVPD is affected by the size of the heart, the intraventricular pressure gradient (IVPG) index, which is unaffected by heart size, is by calculated by dividing IVPD by LV length. In the present study, CMM IVPG was used to non-invasively assess diastolic impairment in cats with obstructive hypertrophic cardiomyopathy. This study was conducted on 10 control cats and 18 cats in the HCM group. Although no severe left atrial enlargement was observed in the HCM group, the basal IVPG was significantly increased in the HOCM group compared to the control group. Although IVPD typically suggests impaired diastolic function and reduced ventricular compliance, the significant increase observed in the HOCM group compared to controls may suggest an indirect elevation in left atrial pressure, likely secondary to left ventricular outflow tract obstruction. The increase in IVPG in HOCM, as shown in this study, is a pathological effect of left ventricular outflow tract obstruction that cannot be detected by conventional echocardiographic indices, and evaluating IVPG is useful to evaluate cardiac function from a perspective that differs from conventional methods.

Background The introduction of a transapical transcatheter beating heart replacement system has significantly expanded therapeutic options for patients with severely diseased mitral valves, particularly those ineligibles for traditional surgery or transcatheter repair. However, challenges, such as left ventricular outflow tract obstruction (LVOT-O) and the risk of dynamic systolic anterior motion (SAM) in cases with elongated anterior mitral leaflet (AML) post-prosthesis implantation, impede the widespread adoption of transcatheter mitral valve replacement (TMVR). Case summary In 2022, a 75-year-old male with severe mixed-genesis mitral regurgitation (MR) underwent Carillon Mitral Contour System annuloplasty. Recurrent heart failure admissions (New York Heart Association IV) and prohibitive risk for open-heart surgery (European System for Cardiac Operative Risk Evaluation II 8.27%) prompted evaluation for Tendyne TMVR with the MitraCut technique. This beating heart transapical approach involved scissor-mediated splitting of the elongated 27 mm AML, essential for mitigating LVOT-O risk and dynamic SAM. The screening echocardiogram revealed the poorly tethered AML near the thickened septum at the simulated neo-LVOT site. Discussion This case underscores the intricate management challenges associated with severe MR, highlighting the successful application of the MitraCut technique as a viable alternative in high-risk scenarios. The imperative for further research and clinical studies is emphasized to comprehensively elucidate outcomes and safety parameters, providing valuable insights for refining TMVR applications within this context. [ABSTRACT FROM AUTHOR]

Septal myectomy is indicated in patients with obstructive hypertrophic cardiomyopathy (HCM) who have persistent symptoms despite medical therapy, intolerance of medication side effects, or severe resting or provocable gradients. Septal myectomy at high volume centers is safe, with low operative mortality (1%) and low rates of complications such as complete heart block or ventricular septal defect (3% and 0.5%, respectively). Additionally, improved survival following myectomy has been observed when compared to patients with obstructive HCM managed medically or those with nonobstructive HCM. As a longstanding, quaternary referral center for septal myectomy, our institution has built significant experience and expertise in the surgical and medical management of HCM, including atypical HCM, defined as preadolescent patients, those with mitral valve disease, and those with isolated midventricular obstruction. The most important factor of septal myectomy in achieving complete resolution of obstruction and avoiding recurrence is the apical extent of the myectomy trough, which must extend to the septum opposite the papillary muscles. If this cannot be fully achieved via a transaortic exposure, especially in preadolescents and patients with midventricular obstruction, then a transapical approach may be needed. Mitral valve repair is rarely necessary as SAM-mediated MR resolves with adequate myectomy alone, but mitral repair is performed in cases of intrinsic valvular disease. In this manuscript we provide a summary of current operative techniques and outcomes data from our institution on the management of these various categories of HCM. [ABSTRACT FROM AUTHOR]

Hypertrophic cardiomyopathy (HCM) is a common contemporary, treatable, genetic disorder that can be compatible with normal longevity. While current medical therapies are ubiquitous, they are limited by a lack of solid evidence, are often inadequate, poorly tolerated, and do not alter the natural disease course. As such, there has long been a need for effective, evidence‐based, and targeted disease‐modifying therapies for HCM. In this review, we redefine HCM as a treatable condition, evaluate current strategies for therapeutic intervention, and discuss novel myosin inhibitors. The majority of patients with HCM have elevated left ventricular outflow tract gradients, which predicts worse symptoms and adverse outcomes. Conventional pharmacological therapies for symptomatic HCM can help improve symptoms but are often inadequate and poorly tolerated. Septal reduction therapies (surgical myectomy and alcohol septal ablation) can safely and effectively reduce refractory symptoms and improve outcomes in patients with obstructive HCM. However, they require expertise that is not universally available and are not without risks. Currently, available therapies do not alter the disease course or the progressive cardiac remodeling that ensues, nor subsequent heart failure and arrhythmias. This has been regarded as an unmet need in the care of HCM patients. Novel targeted pharmacotherapies, namely cardiac myosin inhibitors, have emerged to reverse key pathophysiological changes and alter disease course. Their favorable outcomes led to the early Food and Drug Administration approval of mavacamten, a first‐in‐class myosin modulator, changing the paradigm for the pharmacological treatment of HCM. [ABSTRACT FROM AUTHOR]

Abstract Background Pulmonary hypertension (PH)-associated with left heart disease (Nice PH classification group II) improves when the latter is treated; however, the treatment of PH concomitant with group I PH due to congenital heart disease is difficult, and the optimal pharmacotherapy is controversial. Intervention strategies for the left-sided atrioventricular valve in partial atrioventricular septal defect (AVSD) are problematic. Case presentation A 37-year-old woman who had undergone patch closure for a partial AVSD and mitral valve replacement with a rather large bioprosthesis at the juxta-annular position for mitral regurgitation 12 years earlier was referred to our institute because of severe PH. Echocardiography revealed calcification resulting in severe stenosis of the bioprosthesis and protrusion of its stent post into the left ventricular outflow tract; therefore, redo mitral valve replacement at the supra-annular position was performed using a mechanical valve. Combined group I and II PH gradually improved with meticulous postoperative medical management. Conclusions Severe PH due to stent post protrusion and structural valve deterioration in AVSD was successfully treated with redo mitral valve replacement. The present case was complicated with group I and II PH, for which medical therapy in conjunction with surgical treatment yielded an optimal therapeutic effect.

Background: Elevated left ventricular outflow tract (LVOT) gradients during exercise can occur in patients with hypertrophic cardiomyopathy (HCM) as well as in athletes and normal controls. The authors' staged exercise protocol calls for imaging at rest and during each stage of exercise to evaluate the mechanism of LVOT obstruction at each stage. They investigated whether this staged approach helps differentiate HCM from athletes and normal controls. Methods: They reviewed pediatric exercise stress echocardiograms completed between January 2009 and October 2017 at their center and identified those with gene-positive HCM, athlete's heart, and normal controls. Children with inducible obstruction (those with no LVOT gradient at rest who developed a LVOT peak gradient > 25 mm Hg during exercise) were included. LVOT peak gradient, velocity time integral, acceleration time, and deceleration time were measured at rest, submaximal stages, and peak exercise. Results: Compared with athletes, HCM patients had significantly higher LVOT peak gradients at rest (P = .019), stage 1 of exercise (P = .002), and peak exercise (P = .051), as well as a significantly higher change in LVOT peak gradient from rest to stage 1 (P=.016) and from rest to peak (P = .038). The acceleration time/deceleration time ratio of the LVOT Doppler was significantly lower in HCM patients compared with normal controls at peak exercise. Conclusions: The HCM patients who develop elevated LVOT gradients at peak exercise typically manifest early obstruction in the submaximal stages of exercise, which helps to differentiate them from athletes and normal controls. [ABSTRACT FROM AUTHOR]

Objective: The Yasui operation was introduced in 1987 for patients with 2 adequate ventricles, a ventricular septal defect, and aortic atresia or interrupted aortic arch. Despite promising early outcomes, left ventricular outflow tract obstruction (LVOTO) remains a long-term concern. The purpose of this study is to report our institutional experience with the Yasui operation. Methods: We retrospectively reviewed all patients undergoing the Yasui operation between 1989 and 2021. Results are reported as median with interquartile range (IQR). Results: Twenty-five patients underwent a Yasui operation (19 primary), at 11 days (IQR, 7-218 days) of life and weight of 3 kg (IQR, 2.8-4.1 days). Fundamental diagnosis was ventricular septal defect/interrupted aortic arch in 11 patients and ventricular septal defect/aortic atresia in 14. Follow-up was 96% (24 out of 25) at 5 years (IQR, 1.4-14.7) with 92% survival. Freedom from LVOTO reoperation was 91% at late follow-up with 2 patients requiring baffle revision at 6 and 9 years. Latest echocardiogram showed 100% of patients had normal biventricular function and 87% (20 out of 23) less than mild LVOTO at 5 years (IQR, 2.3-14.9). Diagnosis, aortic valve morphology, and material used were not predictors of LVOTO. Freedom from right ventricle-to-pulmonary artery conduit reoperation was 48% at a median of 5 years (IQR, 1.4-14.7). Conduit type was not a predictor of reintervention. Conclusions: The Yasui operation can be performed with low morbidity and mortality in patients with 2 acceptable-size ventricles and aortic atresia or interrupted aortic arch with severe LVOTO. Despite some burden of reoperation, midterm reoperation for LVOTO is not common and ventricular function is preserved.

Left ventricular outflow tract obstruction (LVOTO) is a notorious complication of transcatheter mitral valve replacement (TMVR). Computed tomography–derived simulations can predict neo-LVOTO post-TMVR, whereas alcohol septal ablation can mitigate neo-LVOTO risk. We report a case of sequential alcohol septal ablation of 2 adjacent septal branches to resolve unexpected neo-LVOTO post-TMVR.

BackgroundThe pulsed-electron avalanche knife (PEAK) PlasmaBlade provides an atraumatic, scalpel-like cutting precision and electrocautery-like hemostasis. PlasmaBlade operates near body temperature, and its long, thin, and malleable tip can overcome the limitations of a surgical knife. In this study, we aimed to evaluate our clinical experience and histopathological outcomes of septal myectomy using PlasmaBlade.MethodsElectronic medical records were reviewed for preoperative, operative, and follow-up data of the patients who underwent septal myectomy using PEAK PlasmaBlade at our institute between January 2019 and December 2022. Histopathology of the myectomy specimens was reviewed for the depth of muscle necrosis and compared with the left atrial appendage (LAA) specimen.ResultsTwenty-nine patients underwent septal myectomy using the PEAK PlasmaBlade. No mortality was reported. The mean age was 60.6 ± 12.5 years, and 58.6% of patients were male. Peak left ventricular outflow tract (LVOT) gradients were 40.5 ± 34.9 mmHg at rest and 56.5 ± 34.9 mmHg after provocation. Concomitant procedures performed were LAA ligation in 20 (69.0%), aortic valve replacement in 5 (17.2%), and coronary artery bypass grafting in 3 (10.3%) patients. Postoperative complications were complete heart block in one (3.4%) and ventricular septal defect in two (6.9%) patients. Both the ventricular septal defects were identified intraoperatively and repaired. Histopathology of myectomy specimens demonstrated cautery artifact limited to 1,000 µm with conventional electrocautery. At a mean follow-up of 8.4 ± 10.3 months, the mean LVOT gradient was 4.4 ± 5.8 mmHg at rest and 9.5 ± 3.3 mmHg after provocation. All patients were alive and in New York Heart Association class I/II. No patient developed complications or required reintervention or reoperation.ConclusionAdequate septal myectomy can be precisely and safely performed using the PEAK PlasmaBlade with minimal collateral damage.

Left ventricular outflow tract obstruction (LVOTO), a major form of outflow tract malformation, accounts for a substantial portion of congenital heart defects (CHDs). Unlike its prevalence, the genetic architecture of LVOTOremains largely unknown. To unveil the genetic mutations and risk genes potentially associated with LVOTO, we enrolled a cohort of 106 LVOTO patients and 100 healthy controls and performed a whole-exome sequencing (WES). 71,430 rare deleterious mutations were found in LVOTO patients. By using gene-based burden testing, we further found 32 candidate genes enriched in LVOTO patient including known pathological genes such as GATA5 and GATA6. Most variants of 32 risk genes occur simultaneously rather exclusively suggesting polygenic inherence of LVOTO and 14 genes out of 32 risk genes interact with previously discovered CHD genes. Single cell RNA-seq further revealed dynamic expressions of GATA5, GATA6, FOXD3 and MYO6 in endocardium and neural crest lineage indicating the mutations of these genes lead to LVOTO possibly through different lineages. These findings uncover the genetic architecture of LVOTO which advances the current understanding of LVOTO genetics. [ABSTRACT FROM AUTHOR]

Background Percutaneous alcohol septal ablation (ASA) is a non-surgical treatment for symptomatic hypertrophic obstructive cardiomyopathy. It has a potential risk for systolic anterior motion (SAM)–related mitral regurgitation (MR) deterioration, leading to acute congestive heart failure. In such clinical scenarios, additional surgical interventions for SAM-MR are risky. Case summary A 70-year-old man experienced acutely deteriorated heart failure caused by SAM-related MR following ASA, for which venous-arterial extracorporeal membrane oxygenation (ECMO) and a percutaneous left ventricular assist device (Impella CP, Abiomed, MA, USA) were required. Transoesophageal echocardiography showed that an interventricular septal oedematous protrusion led to a large coaptation gap of mitral leaflets with a pseudo-prolapse of the posterior mitral leaflet (PML). Because of his prohibitive surgical risks, we opted for transcatheter edge-to-edge mitral valve repair with MitraClip therapy. After removing the Impella device, an XT clip (Abbott Vascular, CA, USA) was located to cover the pseudo-prolapsed PML, resulting in optimal MR reduction with an acceptable mean transmitral valve-pressure gradient. Thereafter, his heart failure was well controlled, and venous-arterial ECMO was successfully removed on post-MitraClip Day 2. Discussion This case demonstrated that MitraClip therapy rescued the patient from a rare complication of severe acute heart failure with haemodynamic collapse caused by massive SAM-related MR following ASA. MitraClip therapy can be a feasible, less-invasive interventional therapy for SAM-related MR in cases with acceptable severity of iatrogenic mitral stenosis post-MitraClip implantation. [ABSTRACT FROM AUTHOR]

Purpose of review: The objectives of this review are to highlight the pathophysiology and treatment strategies of mitral valve regurgitation (MR) in patients with hypertrophic cardiomyopathy (HCM). Recent findings: There is increasing recognition that MR in HCM is related to a complex interaction of abnormalities in the mitral valve and subvalvular apparatus that predispose to development of left ventricular outflow tract (LVOT) obstruction. When lifestyle and pharmacologic treatments do not suffice, surgical myectomy remains the primary therapy for relieving symptomatic obstructive HCM and associated MR. Alcohol septal ablation has also been associated with a reduction in LVOT gradient and MR severity. For patients with MR and intrinsic mitral valve abnormalities, thinner septal walls, or residual MR after septal reduction, concomitant mitral valve repair can be considered. Transcatheter edge-to-edge repair has emerged as an additional option in select cases. Summary: A variety of anatomic and pathophysiologic mechanisms contributes to the development of MR in patients with HCM. Although septal reduction therapies are mostly successful in decreasing the severity of MR, a detailed assessment of mitral valve anatomy and structure is critical in determining which patients might benefit from concomitant surgical or transcatheter mitral valve interventions. [ABSTRACT FROM AUTHOR]

Mitral valve-in-valve (ViV) is associated with suboptimal hemodynamics and rare left ventricular outflow tract (LVOT) obstruction. This study aimed to determine whether device position and asymmetry are associated with these outcomes. Patients undergoing SAPIEN 3 (Edwards Lifesciences) mitral ViV included in the VIVID (Valve-in-Valve International Data) Registry were studied. Clinical endpoints are reported according to Mitral Valve Academic Research Consortium definitions. Residual mitral valve stenosis was defined as mean gradient ≥5 mm Hg. Depth of implantation (percentage of transcatheter heart valve [THV] atrial to the bioprosthesis ring) and asymmetry (ratio of 2 measures of THV height) were evaluated. A total of 222 patients meeting the criteria for optimal core lab evaluation were studied (age 74 ± 11.6 years; 61.9% female; STS score = 8.3 ± 7.1). Mean asymmetry was 6.2% ± 4.4%. Mean depth of implantation was 19.0% ± 10.3% atrial. Residual stenosis was common (50%; mean gradient 5.0 ± 2.6 mm Hg). LVOT obstruction occurred in 7 cases (3.2%). Implantation depth was not a predictor of residual stenosis (OR: 1.19 [95% CI: 0.92-1.55]; P = 0.184), but more atrial implantation was protective against LVOT obstruction (0.7% vs 7.1%; P = 0.009; per 10% atrial, OR: 0.48 [95% CI: 0.24-0.98]; P = 0.044). Asymmetry was found to be an independent predictor of residual stenosis (per 10% increase, OR: 2.30 [95% CI: 1.10-4.82]; P = 0.027). Valve stenosis is common after mitral ViV. Asymmetry was associated with residual stenosis. Depth of implantation on its own was not associated with residual stenosis but was associated with LVOT obstruction. Technical considerations to reduce postdeployment THV asymmetry should be considered. [Display omitted] [ABSTRACT FROM AUTHOR]

Hypertrophic cardiomyopathy (HCM) is a genetic disease characterized by an increased left ventricular wall thickness in the absence of increased afterload conditions. In addition to diastolic dysfunction, obstruction of the left ventricular outflow tract is common in HCM and has an important influence on symptoms and outcome. Over the last five decades or two decades, respectively, surgical myectomy and alcohol septal ablation were the only therapeutic options if standard medical care was not sufficient. Recently, a new option has become available that has the potential to revolutionize the therapeutic strategies for patients with HCM. Mavacamten is a myosin inhibitor that belongs to a completely new drug class and targets the excessive actin–myosin cross-bridging that is the underlying pathology of HCM. By reducing the actin–myosin interactions, mavacamten not only reduces the left ventricular outflow tract (LVOT) obstruction but also seems to have positive effects on the diastolic function, microcirculation, and cardiac structure. This article summarizes the current evidence on alcohol septal ablation and reviews the preclinical and clinical data on mavacamten for the treatment of patients with obstructive HCM. [ABSTRACT FROM AUTHOR]