Systolic anterior motion of the mitral valve in hypertrophic cardiomyopathy: a narrative review

Effect of Mavacamten on Echocardiographic Features in Chinese Patients with Obstructive Hypertrophic Cardiomyopathy: Results from the EXPLORER-CN Study

INTRODUCTION

Mavacamten, a cardiac myosin inhibitor, has demonstrated positive outcomes in left ventricular outflow tract (LVOT) gradient reduction and improvements of symptoms and function in Chinese patients with symptomatic obstructive hypertrophic cardiomyopathy (HCM) in EXPLORER-CN. This exploratory analysis aimed to evaluate the effect of mavacamten on echocardiographic measures of cardiac structure and function and its relationship with other clinical biomarkers.

METHODS

Key echocardiographic parameters acquired over 30 weeks from 81 patients (n = 54 on mavacamten and n = 27 on placebo) were assessed in a central laboratory.

RESULTS

At 30 weeks, greater improvements in measures of diastolic function were observed with mavacamten versus placebo, including lateral E/e' (least-squares mean [LSM] change from baseline [CFB] - 5.1 vs. 0.6; between-group LSM difference - 5.7; 95% confidence interval [CI] - 7.6 to - 3.7), septal E/e' (LSM CFB - 6.0 vs. - 0.3; between-group LSM difference - 5.7; 95% CI - 7.8 to - 3.7), and left atrial volume index (LAVI) (LSM CFB - 11.7 vs. - 3.5 ml/m2; between-group LSM difference - 8.2; 95% CI - 12.0 to - 4.4) (nominal p < 0.001 for all). Twelve patients (23.1%) treated with mavacamten had complete resolution of mitral valve systolic anterior motion (SAM) versus two patients (7.4%) receiving placebo. Among mavacamten-treated patients, reductions in resting and Valsalva LVOT gradients, left ventricular (LV) mass index, LAVI, and lateral and septal E/e' were associated with reduced N-terminal pro-B-type natriuretic peptide levels (nominal p < 0.0001 for all). In the mavacamten group, reductions in LVOT gradients and LV end-diastolic interventricular septal thickness were associated with improved patient-reported Kansas City Cardiomyopathy Questionnaire Overall Summary Score (nominal p < 0.05 for all).

CONCLUSIONS

Clinically meaningful improvements were evident in Chinese patients treated with mavacamten compared with placebo in several hallmarks of obstructive HCM, including measures of LV diastolic function, SAM, and LVOT gradient. These results add further evidence to support the positive effects of mavacamten in cardiac remodeling.

REGISTRATION

ClinicalTrials.gov identifier: NCT05174416.

Investigating the Anrep Effect in Hypertrophic Obstructive Cardiomyopathy With Invasive Pressure-Volume Analysis

BACKGROUND

The Anrep effect, an adaptation enhancing left ventricular (LV) contractility in response to raised afterload, is hypothesized to influence hypertrophic cardiomyopathy pathophysiology.

OBJECTIVES

This study investigated the activation and reversibility of the Anrep effect in obstructive hypertrophic cardiomyopathy (HOCM) patients undergoing percutaneous transluminal septal myocardial ablation (PTSMA) to relieve LV outflow tract obstruction.

METHODS

Invasive pressure-volume (PV) analysis was performed on 14 HOCM patients before and after PTSMA. The "Anrep Triad," defined by elevated afterload (higher LV end-systolic pressure and effective arterial elastance), augmented contractility (higher end-systolic elastance and maximum LV pressure rise [dP/dtmax]), and prolonged systolic duration (dTes), was assessed via direct hemodynamic comparison preprocedure and postprocedure. Stroke work (SW), potential energy, and total PV area (PVA) quantified mechanical work and efficiency (SW/PVA).

RESULTS

Postprocedure reversal of the Anrep effect was confirmed (pre- vs post-PTSMA), with reductions in afterload (LV end-systolic pressure: 180 vs 138 mm Hg, P = 0.0001; effective arterial elastance: 2.5 vs 1.9 mm Hg/mL, P = 0.002), contractility (end-systolic elastance: 2.0 vs 1.5 mm Hg/mL, P = 0.0001; dP/dtmax: 1,775 vs 1,560 mm Hg/s, P = 0.017), and systolic duration (dTes: 371 vs 327 ms, P = 0.002). Preprocedure, HOCM patients exhibited higher mechanical workload (SW: 8,161 vs 7,495 mm Hg·mL, P = 0.004; potential energy: 7,837 vs 4,915 mm Hg·mL, P = 0.002; PVA: 16,135 vs 11,742 mm Hg·mL, P = 0.0002) and lower efficiency (SW/PVA: 50% vs 59%, P = 0.03).

CONCLUSIONS

The Anrep effect is an energy-demanding compensatory mechanism that maintains stroke volume under elevated afterload by increasing contractility and prolonging systole. This study confirms its chronic activation in HOCM and its immediate reversal post-PTSMA.

Alcohol Septal Ablation for Hypertrophic Obstructive Cardiomyopathy With Midventricular Obstruction and Papillary Muscle Abnormalities

Although abnormal mitral valve complexes are frequently observed, alcohol septal ablation (ASA) for hypertrophic obstructive cardiomyopathy (HOCM) with an anomalous papillary muscle (PM) is challenging. We present the case of a 65-year-old woman with HOCM concomitant with midventricular obstruction and anomalous PMs. She was referred to our hospital for septal reduction therapy to alleviate recurrent syncope, chest pain, and heart failure symptoms. ASA was performed to ablate the left ventricular (LV) myocardium from the base to the middle via 6 septal branches. The pressure gradient in the LV outflow tract decreased considerably, and midventricular obstruction persisted immediately after ASA. There were no recurrent episodes of syncope or chest pain, and the heart failure-related symptoms improved. Eighteen months later, the LV outflow tract and midventricular obstructions were relieved. This case indicates that ASA is an alternative option to relieve symptoms, even if anomalous PMs and midventricular obstruction coexist in HOCM.

Comparison of Alcohol Septal Ablation With Mavacamten in Obstructive Hypertrophic Cardiomyopathy

Obstructive hypertrophic cardiomyopathy (HCM) is associated with significant morbidity attributed to left ventricular outflow tract (LVOT) obstruction. Although alcohol septal ablation (ASA) is an established interventional treatment, mavacamten, a novel cardiac myosin inhibitor, has emerged as a noninvasive pharmacologic alternative. Understanding the comparative efficacy of these 2 treatments is important for optimizing patient care. This single-center retrospective study assessed the hemodynamic and functional changes in adult patients with obstructive HCM treated with ASA (n = 58) or mavacamten (n = 36) from July 2012 to May 2024. Outcomes, including changes in LVOT gradient, left ventricular ejection fraction, mitral regurgitation (MR) severity, and New York Heart Association (NYHA) class, were collected at baseline, 16 weeks, and after 32 weeks of treatment. ASA and mavacamten were associated with over 70% reductions in Valsalva-induced LVOT gradient and MR after 32 weeks. The maximal effect of ASA on LVOT gradient was observed at 16 weeks, whereas mavacamten's peak effect was noted after 32 weeks. MR severity improved similarly in both cohorts (p <0.01). Patients who underwent ASA had a poorer baseline NYHA functional class than their counterparts; however, each treatment significantly improved LVOT gradients (p <0.001) and average NYHA class after 32 weeks (p <0.001). The average left ventricular ejection fraction was comparable at baseline and after 32 weeks between the 2 groups. Patients treated with ASA were older than those treated with mavacamten (68.5 vs 60.8 years, p <0.001). In patients with obstructive HCM, ASA and mavacamten yield significant and comparable improvements in hemodynamics and functional status after 32 weeks.

Mitral regurgitation in patients with hypertrophic cardiomyopathy: a case series

Background

Mitral regurgitation (MR) is a frequent occurrence in hypertrophic cardiomyopathy (HCM), often explained by valvular or sub-valvular abnormalities as part of a broad HCM phenotype spectrum.

Case summary

In this case series, we present two HCM cases diagnosed with systolic anterior motion of the anterior mitral valve (MV) leaflet and left ventricular outflow tract (LVOT) obstruction. Both cases had abnormal sub-valvular abnormalities that led to deterioration of LVOT obstruction and MR. The series highlights the need for close collaboration within a multidisciplinary team, with a special emphasis on the need for a personalized treatment strategy when considering septal reduction therapy and/or MV surgery.

Discussion

Mitral regurgitation is linked to adverse cardiac outcomes, often contributing towards symptoms, poor functional capacity, hospitalization, and advanced therapies. Complex and interlinked biomechanical factors lead to MR, often co-existing with LVOT obstruction. Multimodality imaging with echocardiography (transthoracic and transoesophageal) and cardiac magnetic resonance imaging plays a key role in determining the aetiology of MR in HCM. This case series highlights the role of this comprehensive assessment, paving the way for a personalized treatment pathway for patients.

The clinical utility of cardiac myosin inhibitors for the management of hypertrophic cardiomyopathy: a scoping review

Hypertrophic cardiomyopathy (HCM) is an inherited condition characterized by left ventricular, non-dilated hypertrophy in the absence of another secondary underlying cause. There has been an ongoing increase in the diagnosis of HCM over the past couple of decades, prompting further work in the area of pharmacological and interventional therapies. This scoping review aimed to summarize the traditional therapeutic options for HCM and to explore emerging research on novel cardiac myosin inhibitors (CMIs) as a new option for pharmacologic management of HCM. A PRISMA search strategy was carried out to identify the pertinent literature on mavacamten and aficamten-two novel CMIs. Seventeen studies were included. Based on the results of the studies included in this review, cardiac myosin inhibitors have been proven to be a safe and efficacious second-line option for the management of HCM. In the foreseeable future, based on results of ongoing studies investigating patient outcomes and side-effect profile, CMIs may potentially play a larger role as part of standard treatment of HCM.

Hispanic-Latino Race is Associated with Worse Heart Failure Symptoms in Patients with Hypertrophic Cardiomyopathy

BACKGROUND

Data regarding racial differences in patients with hypertrophic cardiomyopathy (HCM) is sparse. We hypothesized that Hispanic-Latino (HL), Non-Hispanic (NH), and African-American (AA) race impacts the clinical presentation of HCM.

METHODS

A total of 641 HCM patients (HL = 294, NH = 274, AA = 73) were identified retrospectively from our institutional registry between 2005-2021. Clinical characteristics, echocardiographic indices, and outcomes were assessed using analysis of variance, Kruskal-Wallis, and multivariate linear regression statistical analyses, with Dunn-Bonferroni and Tukey test applied in post-hoc pairwise assessments.

RESULTS

The HL and NH patients were older compared with AA (69.2 ± 14.7 vs 67.9 ± 15.3 vs 59.4 ± 15.8 years; p < 0.001). The HL group had higher prevalence of females compared with NH (62 vs 47%; p = 0.002), and more moderate-severe mitral regurgitation (35 vs 23 vs 12% p < 0.001) and a higher E/e' ratio (16.4 ± 8.1 vs 14.9 ± 6.6 vs 13.3 ± 4.5; p = 0.002) when compared with NH and AA. Multivariate linear regression analysis revealed HL ethnicity (β = 0.1) was associated with worse New York Heart Association (NYHA) class independent from moderate-severe mitral regurgitation (β = 0.2), chronic obstructive pulmonary disease (β = 0.17), female gender (β = 0.13), coronary artery disease (β = 0.12), atrial fibrillation (β = 0.11), peak trans-mitral E-wave velocity (β = 0.11), left ventricular mass index (β = 0.1), and reverse septal curve morphology (β = 0.1) (model, r = 0.5, p < 0.001). At 2.5-year median follow-up, all-cause mortality (8%) and composite complications (33%) were similar across the cohort.

CONCLUSIONS

HCM patients of HL race have worse heart failure symptoms when compared with NH and AA, with severity independent of cardiovascular co-morbidities.

Mid-ventricular hypertrophic cardiomyopathy with apical aneurysm: a multimodality imaging case report

Mid-ventricular hypertrophic cardiomyopathy is a rare subgroup within hypertrophic cardiomyopathies that may present with apical aneurysm. This condition is associated with an increased risk of cardiac adverse events, including cardiac arrest, heart failure, thromboembolic events, or sudden cardiac death. We present a case of a 41-year-old man who presented with a history of exertional dyspnea and syncope. Multimodality imaging with echocardiography and cardiac magnetic resonance showed hypertrophy of the mid-ventricular segments with apical aneurysm. An implantable cardioverter-defibrillator was implanted to prevent sudden cardiac death.

Tailored Therapies for Cardiogenic Shock in Hypertrophic Cardiomyopathy: Navigating Emerging Strategies

Hypertrophic cardiomyopathy (HCM) is a complex and heterogeneous cardiac disorder, often complicated by cardiogenic shock, a life-threatening condition marked by severe cardiac output failure. Managing cardiogenic shock in HCM patients presents unique challenges due to the distinct pathophysiology of the disease, which includes dynamic left ventricular outflow tract obstruction, diastolic dysfunction, and myocardial ischemia. This review discusses current and emerging therapeutic strategies tailored to address the complexities of HCM-associated cardiogenic shock and other diseases with similar pathophysiology that provoke left ventricular outflow tract obstruction. We explore the role of pharmacological interventions, including the use of vasopressors and inotropes, which are crucial in stabilizing hemodynamics but require careful selection to avoid exacerbating the outflow obstruction. Additionally, the review highlights advancements in mechanical circulatory support devices such as extracorporeal membrane oxygenation (ECMO) and left ventricular assist devices (LVADs), which have become vital in the acute management of cardiogenic shock. These devices provide temporary support and bridge patients to recovery, definitive therapy, or heart transplantation, which remains a critical option for those with end-stage disease. Furthermore, the review delves into the latest research and clinical trials that are refining these therapeutic approaches, ensuring they are optimized for HCM patients. The impact of these treatments on patient outcomes, including survival rates and quality of life, is also critically assessed. In conclusion, this review underscores the importance of a tailored therapeutic approach in managing cardiogenic shock in HCM patients, integrating pharmacological and mechanical support strategies to improve outcomes in this high-risk population.

Echocardiographic and Clinical Outcomes of Concomitant Secondary Chordal Cutting to Surgical Myectomy in Hypertrophic Obstructive Cardiomyopathy: A Systematic Review and Meta-analysis

In patients who underwent surgical myectomy for hypertrophic obstructive cardiomyopathy (HOCM), additional mitral valve repair may offer additional benefits in terms of further reducing left ventricular outflow tract (LVOT) gradients, systolic anterior motion (SAM), and mitral regurgitation (MR). We performed a systematic review of the literature to evaluate the evidence of surgical myectomy with additional secondary chordal cutting in patients with HOCM. A systematic literature search in MEDLINE and EMBASE was performed until April 2024. The primary outcome studied was postoperative echocardiographic LVOT gradient. A random effects meta-analysis of means was performed for the primary outcome. The secondary outcomes studied were postoperative residual MR grade, 30-day new permanent pacemaker implantation, and in-hospital mortality. From 1,911 unique publications, a total of 6 articles fulfilled the inclusion criteria and comprised 471 patients with a pooled mean preoperative resting LVOT gradient of 84 mm Hg (95% confidence interval [CI]: 76-91). The postoperative pooled mean LVOT gradient was 11 mm Hg (95% CI: 10-12) with a low heterogeneity (I 2 = 44%). The residual LVOT gradient exceeding 30 mm Hg was present in nine (1%) patients. MR grade 3 or 4 at hospital discharge was present in seven (1%) patients. The 30-day new permanent pacemaker implantation rate was 7% and the in-hospital mortality was 0.4%. This systematic review and meta-analysis demonstrate that combining surgical myectomy with secondary chordal cutting can be performed safely and effectively eliminate LVOT obstruction in HOCM patients. Further studies are needed to determine the additive effectiveness of additional secondary chordal cuttings.

Longitudinal assessment of systolic anterior motion of the mitral valve in cats with hypertrophic cardiomyopathy

BACKGROUND

The proportion of cats with hypertrophic cardiomyopathy (HCM) that lose systolic anterior motion of the mitral valve (SAM) in the long term is unknown.

HYPOTHESIS/OBJECTIVES

Cats with HCM will lose SAM in the long term. Loss of SAM will be associated with greater age, longer scan-interval, and altered left ventricular (LV) dimensions.

ANIMALS

Sixty unsedated cats with HCM, not receiving beta blockers or pimobendan.

METHODS

A retrospective cohort study from 2 referral centers. Cats were eligible if they had been diagnosed with HCM and had a repeat echocardiogram ≥1 year later. Clinical and echocardiographic data of the left heart variables were collected.

RESULTS

Thirty-eight cats had SAM at the initial scan. After a median follow-up time of 2.1 years (range: 1.0-5.9), 7 cats had lost SAM (18%) and 5 cats (23%) gained SAM. On follow-up, cats with SAM at the initial scan had a larger left atrium (P = .037), lower left atrial fractional shortening (P = .014), greater LV internal diameter in end-systole (P = .002), and lower LV fractional shortening (P < .001). Four cats with SAM developed congestive heart failure. There were no new cases of congestive heart failure or change in left heart variables in cats without SAM at the initial scan. The gain or loss of SAM was not associated with age or time between scans.

CONCLUSIONS AND CLINICAL IMPORTANCE

Similar proportions of cats gained or lost SAM. Cats with SAM at baseline had more evidence of disease progression than cats without SAM.

Hypertrophic Cardiomyopathy as a Form of Heart Failure with Preserved Ejection Fraction: Diagnosis, Drugs, and Procedures

Hypertrophic cardiomyopathy (HCM) is a complex and heterogeneous cardiac disorder characterized by cardiac hypertrophy disproportionate to loading stimuli (e.g. hypertension or aortic stenosis). Diagnosing HCM requires a thorough examination of clinical symptoms, with echocardiography as the key initial imaging tool. Multimodality imaging further supports diagnosis, helps assess left ventricular outflow obstruction, and aids in risk stratification for sudden cardiac death. The cornerstone of HCM management remains pharmacological therapy with β-blockers and calcium channel blockers serving as first-line agents to alleviate symptoms and reduce left ventricular outflow tract obstruction. More recently, cardiac myosin inhibitors have revolutionized the treatment paradigm for obstructive HCM. Procedural interventions such as septal reduction therapy are reserved for refractory cases. Genetic testing and risk stratification for sudden cardiac death play a critical role in treatment decisions, guiding further testing in first-degree relatives and ICD implantation in high-risk individuals. Exercise recommendations have evolved based on recent data, challenging traditional restrictions and emphasizing individualized plans.

Alcohol septal ablation for hypertrophic obstructive cardiomyopathy: do mitral valve leaflet length, septal thickness, or sex affect the outcome?

This retrospective cohort study aimed to assess whether basal septal wall thickness (BSWT), anterior (AML) and posterior (PML) mitral leaflet length, or sex were associated with remaining left ventricular outflow tract obstruction (LVOTO) in patients with hypertrophic obstructive cardiomyopathy (HOCM) undergoing alcohol septal ablation (ASA). One hundred fifty-four patients who underwent ASA at the Karolinska University Hospital in Stockholm, Sweden, between 2009 and 2021, were included retrospectively. Anatomical and hemodynamic parameters were collected from invasive catheterization before and during ASA, and from echocardiography (ECHO) examinations before, during, and at 1-year follow-up after ASA. Linear and logistic regression models were used to assess the association between sex, BSWT, AML, PML, and outcome, which was defined as the remaining LVOTO (≥ 30 mmHg) after ASA. The median follow-up was 364 days (interquartile range 334-385 days). BSWT ≥ 23 mm (n = 13, 12%) was associated with remaining LVOTO at follow-up (p = 0.004). Elongated mitral valve leaflet length (either AML or PML) was present in 125 (90%) patients. Elongated AML (> 24 mm) was present in 67 (44%) patients, although AML length was not associated with remaining LVOTO at follow-up. Elongated PML (> 14 mm) was present in 114 (74%) patients and was not associated with remaining LVOTO at follow-up. No significant sex differences were observed regarding the remaining LVOTO. ECHO measurement of BSWT can be effectively used to select patients for successful ASA and identify those patients with a risk of incomplete resolution of LVOTO after ASA.

Three-dimensional anatomic features of the mitral valve that predict systolic anterior motion occurring during dobutamine stress echocardiography

BACKGROUND/AIM

Left ventricular outflow tract obstruction related to systolic anterior motion (SAM) of the mitral valve is a common complication of dobutamine stress echocardiography (DSE). However, the mechanisms underlying SAM have not been fully characterized. The objective of the present study was to use three-dimensional echocardiography to identify anatomic features of the mitral valve that predispose to SAM during DSE.

METHODS

We retrospectively evaluated consecutive patients included prospectively in our database and who had undergone 3D echocardiography (including an assessment of the mitral valve) before DSE. Patients who had developed SAM during DSE (the SAM+ group) were matched 2:3 with patients who did not (the SAM- group).

RESULTS

One hundred patients were included (mean age: 67 ± 10). Compared with SAM- patients (n = 60), SAM+ patients (n = 40) had a lower mitral annular area, a smaller perimeter, and a smaller diameter (p < .01 for all, except the anteroposterior diameter). The SAM+ group had also a narrower mitral-aortic angle (126 ± 12° vs. 139 ± 11° in the SAM- group; p < .01) and a higher posterior mitral leaflet length (1.4 ± .27 cm vs. 1.25 ± .29, respectively; p < .01). Furthermore, the mitral annulus was more spherical, more flexible, and more dynamic in SAM+ patients than in SAM- patients (p < .05 for all). In a multivariate analysis of anatomic variables, the mitral-aortic angle, the mitral annular area, and posterior leaflet length were independent predictors of SAM (p ≤ .01 for all). In a multivariate analysis of standard echo and hemodynamic variables, the presence of wall motion abnormalities at rest (p < .01) was an independent predictor of SAM.

CONCLUSION

SAM during DSE is multifactorial. In addition to the pharmacologic effects of dobutamine on the myocardium, 3D echocardiographic features of the mitral valve (a smaller mitral annulus, a narrower mitral-aortic angle, and a longer posterior leaflet) appear to predispose to SAM.

Retrofitting the Heart: Explaining the Enigmatic Septal Thickening in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy is the most common genetic cardiac disease and is characterized by left ventricular hypertrophy. Although this hypertrophy often associates with sarcomeric gene mutations, nongenetic factors also contribute to the disease, leading to diastolic dysfunction. Notably, this dysfunction manifests before hypertrophy and is linked to hypercontractility, as well as nonuniform contraction and relaxation (myofibril asynchrony) of the myocardium. Although the distribution of hypertrophy in hypertrophic cardiomyopathy can vary both between and within individuals, in most cases, it is primarily confined to the interventricular septum. The reasons for septal thickening remain largely unknown. In this article, we propose that alterations in muscle fiber geometry, present from birth, dictate the septal shape. When combined with hypercontractility and exacerbated by left ventricular outflow tract obstruction, these factors predispose the septum to an isometric type of contraction during systole, consequently constraining its mobility. This contraction, or more accurately, this focal increase in biomechanical stress, prompts the septum to adapt and undergo remodeling. Drawing a parallel, this is reminiscent of how earthquake-resistant buildings are retrofitted with vibration dampers to absorb the majority of the shock motion and load. Similarly, the heart adapts by synthesizing viscoelastic elements such as microtubules, titin, desmin, collagen, and intercalated disc components. This pronounced remodeling in the cytoskeletal structure leads to noticeable septal hypertrophy. This structural adaptation acts as a protective measure against damage by attenuating myofibril shortening while reducing cavity tension according to Laplace Law. By examining these events, we provide a coherent explanation for the septum's predisposition toward hypertrophy.

Predictive value of estimated plasma volume for postoperative hypotension in percutaneous intramyocardial septal radiofrequency ablation treating for hypertrophic obstructive cardiomyopathy

BACKGROUND

Estimated plasma volume status (ePVS) estimated by the Duarte formula is associated with clinical outcomes in patients with heart failure. It remains unclear the predictive value of the ePVS to the postoperative hypotension (POH) in percutaneous intramyocardial septal radiofrequency ablation (PIMSRA) treating hypertrophic obstructive cardiomyopathy (HOCM).

METHODS

Data of HOCM patients who underwent PIMSRA were retrospectively collected. Preoperative ePVS was calculated using the Duarte formulas which derived from hemoglobin and hematocrit ratios. Clinical variables including physical assessment, biological and echocardiographic parameters were recorded. Patients were labeled with or without POH according to the medical record in the hospital. Univariable and multivariable logistic regression were performed to evaluate the association between ePVS and POH. Using different thresholds derived from quartiles and the best cutoff value of the receiver operating characteristic curve, the diagnostic performance of ePVS was quantified.

RESULTS

Among the 405 patients included in this study, 53 (13.1%) patients were observed with symptomatic POH. Median (IQR) of ePVS in overall patients was 3.77 (3.27~4.40) mL/g and in patients with POH were higher than those without POH. The ePVS was associated with POH, with the odds ratio of 1.669 (95% CI 1.299 ~ 2.144) per mL/g. After adjusted by potential confounders, ePVS remained independently associated with POH, with the approximate odds ratio in different models.

CONCLUSION

The preoperative ePVS derived from the Duarte formulas was independently associated with postoperative hypotension in HOCM patients who underwent PIMSRA and showed prognostic value to the risk stratification of postoperative management.

TRIAL REGISTRATION

NCT06003478 (22/08/2023).

Extended septal myectomy for obstructive hypertrophic cardiomyopathy and its impact on mitral valve function

AIMS

Septal myectomy is the treatment of choice for hypertrophic obstructive cardiomyopathy (HOCM). Around 30-60% of patients with HOCM have a secondary mitral valve regurgitation due to systolic anterior motion (SAM). We report our experience with extended septal myectomy and its impact on the incidence of concomitant mitral valve procedures.

METHODS

This is a retrospective study on 84 patients who underwent SM from January 2008 to February 2022. Surgical procedure was performed according to the concept of 'extended myectomy' described by Messmer in 1994. Follow-up outcomes in terms of survival, hospital admissions for heart failure or MV disease, cardiac reoperations, and pacemaker (PMK) implantation were recorded.

RESULTS

Mean age was 61 ± 15 years. Mitral valve surgery was performed in seven cases (8%); particularly only one patient without degenerative mitral valve disease underwent mitral valve surgery, with a plicature of the posterior leaflet. In-hospital mortality was 5%. Mitral valve regurgitation greater than mild was present in four patients (5%) at discharge. Twelve-year survival was 78 ± 22%. Cumulative incidence of rehospitalization for heart failure and rehospitalization for mitral valve disease was 10 ± 4 and 2.5 ± 2.5%, respectively. PMK implantation was 5% at discharge, with a cumulative incidence of 15 ± 7%. Freedom from cardiac reoperations was 100%.

CONCLUSION

Septal myectomy for HOCM is associated with good outcomes. Although concomitant surgery on the mitral valve to address SAM and associated regurgitation has been advocated, these procedures were needed in our practice only in patients with intrinsic mitral valve disease. Adequate myectomy addresses the underlying pathophysiology in most patients.

Short time effects of two radiofrequency ablation methods on hypertrophic obstructive cardiomyopathy

BACKGROUND

Radiofrequency ablation has been applied for the treatment of hypertrophic obstructive cardiomyopathy (HOCM). The two known procedures are percutaneous intramyocardial septal radiofrequency ablation (PIMSRA) and endocardial radiofrequency septal ablation (ERSA).

METHODS

This study presents a retrospective analysis of the PIMSRA and ERSA procedures in patients with drug-refractory HOCM. A total of 28 patients participated in the study, with 12 receiving PIMSRA and 16 receiving ERSA. The objective of our study was to compare the short-term effects of these two radiofrequency ablation procedures.

RESULTS

At the 30-day follow-up, the PIMSRA group demonstrated a greater reduction in left ventricular outflow tract peak gradient at rest compared to the ERSA group (22.25 [16.72] mmHg versus 47.75 [21.94] mmHg) (p < .01). The values for the PIMSRA group decreased from 99.33 (32.00) mmHg to 22.25 (16.72) mmHg (p < .01), while the ERSA group decreased from 97.75 (30.24) mmHg to 47.75 (21.94) mmHg (p < .01). Only the PIMSRA group exhibited a decrease in mitral regurgitation (MR). The area of MR decreased from 10.13 (4.12) mm2 to 3.65 (2.80) mm2 in the PIMSRA group (p < .01). Additionally, the PIMSRA group experienced reductions in left atrial diameter (LAD) and left ventricular ejection fraction (LVEF)%. The values for LAD changed from 43.58 (7.53) mm to 37.08 (6.92) mm (p = .03), and the values for LVEF% decreased from 65.75 (6.12) pg/mL to 60.83 (4.06) pg/mL (p = .03).

CONCLUSION

In terms of the two types of radiofrequency ablation methods used in HOCM, it has been observed that PIMSRA demonstrates a more favorable early treatment effect compared to ERSA.

Role of Imaging in the Diagnosis, Evaluation, and Management of Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is increasingly recognized and may benefit from the recent approval of new, targeted medical therapy. Successful management of HCM is dependent on early and accurate diagnosis. The lack of a definitive diagnostic test, the wide variation in phenotype and the commonness of phenocopy conditions, and the presence of normal or hyperdynamic left ventricular function in most patients makes HCM a condition that is highly dependent on imaging for all aspects of management including, diagnosis, classification, predicting risk of complications, detecting complications, identifying risk for ventricular arrhythmias, evaluating choice of therapy and monitoring therapy, intraprocedural guidance, and screening family members. Although echocardiographic imaging remains the mainstay in the diagnosis and subsequent management of HCM, this disease clearly requires multimethod imaging for various aspects of optimal patient care. Advances in echocardiography hardware and techniques, development and refinement of imaging with computed tomography, magnetic resonance, and nuclear scanning, and the emergence of very focused assessments such as diastology and fibrosis imaging have all advanced the diagnosis and management of HCM. In this review, we discuss the relative utility and evidence support for these imaging approaches to contribute to improve patient outcomes.

Mitral regurgitation mechanisms related to systolic anterior motion in hypertrophic cardiomyopathy

Background

Systolic anterior motion (SAM) of the mitral valve can result in mitral regurgitation (MR) and adverse outcomes in patients with obstructive hypertrophic cardiomyopathy (HCM). However, the mechanism and characteristics of MR severity mediated by SAM are unresolved. This study aimed to elucidate the anatomic and hemodynamic associations of MR and the impact of septal myectomy on changes in MR severity in patients with HCM.

Methods

We retrospectively reviewed patients who underwent septal myectomy with SAM and interpretable imaging between 2017-2022. Significant MR was defined as moderate or more MR. The mitral valve, papillary muscle, and left ventricular geometry were quantitatively evaluated via echocardiography and cardiac computed tomography.

Results

Out of 34 patients, two groups were identified: those with preoperative significant MR (n=16) and those without significant MR (n=18). Patients with significant preoperative MR exhibited worse heart failure symptoms at baseline than those without. Following myectomy, these patients showed higher residual left ventricular outflow tract (LVOT) gradients at rest and with provocative measures than those without preoperative MR. Multivariate regression analysis revealed a significant association between the tenting area and MR severity. Additionally, the chordal cutting procedure alleviated the tenting area [2.1 (1.8-2.6) vs. 1.4 (1.2-1.6) cm2] compared to those without it.

Conclusions

Our preliminary data suggested that chordal cutting with septal myectomy was associated with an improvement in the tenting area, contributing to MR severity. This procedure may serve as an effective therapy for patients with SAM and significant MR.

Anomalous papillary muscle insertion into the mitral valve leaflet in hypertrophic obstructive cardiomyopathy: a lip nevus sign in echocardiography

Background

Anomalous papillary muscle (APM) insertion into the mitral valve leaflet is rare but clinically important in hypertrophic obstructive cardiomyopathy (HOCM). In this study, we report the detection rate of APM insertion into the mitral valve using preoperative imaging modalities and the surgical outcomes of the patients.

Methods

By retrospectively reviewing the clinical records of patients with HOCM who underwent surgical treatment by a single operation group at our center from January 2020 to June 2023, patients with APM insertion into the mitral valve leaflet were identified. Baseline data, image characteristics, and surgical outcomes were analyzed.

Results

The incidence of APM insertion into the mitral valve leaflet was 5.1% (8/157). The insertion site was located at A3 in six cases, which was more common than at A2 (n = 2). Preoperative echocardiography was used to identify two patients (25%) with APM insertion. We observed a particular echocardiographic feature for APM in HOCM patients, which was noted as a "lip nevus sign", with a higher detection rate (62.5%). All patients successfully underwent septal myectomy with concomitant APM excision or mitral valve replacement via the transaortic (n = 5) or transmitral (n = 3) approach. The mean age was 49.0 ± 17.4 years and seven patients (87.5%) were female. Interventricular septum thickness (17.0 mm vs. 13.3 mm, P = 0.012) and left ventricular outflow gradient (117.5 mmHg vs. 7.5 mmHg, P = 0.012) were significantly decreased after surgery. Residual outflow obstruction, systolic anterior motion, and ≥3+ mitral regurgitation were negative. During the follow-up of 26.2 ± 12.2 months, there were no reported operations, adverse events, mitral regurgitation aggravations, recurrences of outflow obstruction, or instances of SAM.

Conclusions

Papillary muscles inserted into the mitral valve leaflet are a subtype of subvalvular malformation in HOCM that requires surgical correction. The lip nevus sign on echocardiography is a characteristic of APM insertion in HOCM and may improve the preoperative detection rate. Adequate myectomy with anomalous papillary muscle excision has achieved good results in reducing the outflow gradient and eliminating mitral regurgitation, with good outcomes at short-to-intermediate follow-up.

Management of the mitral valve in thoracoscopic trans-mitral myectomy for hypertrophic obstructive cardiomyopathy

Objective

This study aimed to compare clinical outcomes of different mitral valve (MV) management methods in thoracoscopic transmitral myectomy (TTM) and guide surgeons' decision making for hypertrophic obstructive cardiomyopathy (HOCM).

Methods

Seventy-three consecutive patients (41 females; mean age, 53.7 ± 13.6 years) with HOCM who underwent TTM between January 2019 and October 2022 were enrolled and divided into 3 groups according to MV surgical strategy. Clinical outcomes were analyzed and compared among the groups.

Results

None of the patients experienced postoperative residual left ventricular outflow tract obstruction. Percentages of patients with mitral regurgitation (MR) grade ≥3+ (57.5% vs 1.4%) and systolic anterior motion (95.9% vs 2.7%) were significantly decreased postoperatively (P < .001 for both). The preoperative anterior mitral leaflet length was longer in patients in the anterior mitral leaflet direct reattachment group (median, 2.9 cm [interquartile range (IQR), 2.7-3.3 cm] vs 2.7 [IQR, 2.4-2.9 cm]; P = .018), but the postoperative coaptation length was shorter (mean, 8.3 ± 2.1 mm vs 11.1 ± 3.8 mm; P = .038). After a median echocardiography follow-up of 11.8 months, the left ventricular outflow tract gradient (LVOTG) and mitral regurgitation grades remained significantly improved in all 3 groups (P < .05 for all).

Conclusions

Total TTM in selected patients is safe and effective, and all 3 MV management strategies can significantly reduce the LVOTG while improving MR. Mitral valvuloplasty is the preferred initial management strategy over valve replacement except in the scenario of irreparable intrinsic MV disease and valvuloplasty failure.

Septal Myectomy and Subvalvular Repair in Hypertrophic Cardiomyopathy, a Systematic Review and Pooled Analysis

Background

Some patients with hypertrophic obstructive cardiomyopathy (HOCM) still exhibit systolic anterior motion (SAM) and mitral regurgitation (MR) even after undergoing an isolated ventricular septectomy. Currently, there are disputes regarding whether to perform a mitral valve intervention and which type of operation is more effective.

Methods

By searching PubMed, Cochrane, Embase, Web of Science, FDA.gov, and ClinicalTrials.gov, as well as other resource databases, we obtained all articles published before December 2022 on ventricular septal myectomy combined with mitral valve intervention for hypertrophic cardiomyopathy. Demographic information and outcome variable data were extracted from 10 screened studies on ventricular septal resection combined with mitral valve repair. The risk of bias was assessed using methodological index for non-randomized studies (MINORS). Student's t-test was used for comparisons of continuous variables, and the chi-square or Fisher's exact test was used for dichotomous variables. A total of 692 patients across 10 studies were analyzed.

Results

There were 5 (0.7%) deaths in the perioperative period. The average cardiopulmonary bypass time was 64.7 ± 22.2 minutes, and the average follow-up time was 39.6 ± 36.3 months. Compared with baseline levels, the left ventricular outflow tract gradient (83.6 ± 32.2 mmHg vs. 11.0 ± 7.8 mmHg, p < 0.01), maximum interventricular septal thickness (22.5 ± 5.1 mm vs. 14.7 ± 5.5 mm, p < 0.01), III/IV mitral regurgitation (351/692 vs. 17/675, p < 0.01), anterior mitral leaflet (AML)-annulus ratio (0.49 ± 0.14 vs. 0.60 ± 0.12, p < 0.01), tenting area (2.72 ± 0.60 cm 2 vs. 1.95 ± 0.60 cm 2 , p < 0.01), and SAM (181/194 vs. 11/215, p < 0.01) were significantly improved. 14 (2.1%) patients were in New York Heart Association functional class III/IV, which was significantly improved compared with the preoperative state (541/692 vs. 14/682, p < 0.01).

Conclusions

Ventricular septectomy combined with mitral valve repair can be a safe and effective treatment option for patients suffering from HOCM with SAM and severe MR.