2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines.

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.

The Risk of Ventricular Arrhythmias between Alcohol Septal Ablation and Septal Myectomy in Hypertrophic Cardiomyopathy: A Meta-Analysis on Septal Reduction Therapy.

Background: Alcohol septal ablation (ASA) has been more commonly applied in medical refractory hypertrophic obstructive cardiomyopathy (HOCM) compared with septal myectomy (SM), however its potential to create a proarrhythmic substrate is increased. Methods: A systematic search was performed in PubMed, EMBASE, Web of Science, and the Cochrane Library from inception to October 2020. Fixed or random effects models were used to estimate the risk ratios (RR) for ventricular arrhythmia events or other outcomes between the SM and ASA cohorts. Results: Twenty studies with 8025 patients were included. Pool analysis showed that the incidence of ventricular tachycardia (VT)/ventricular fibrillation (VF), which included appropriate implantable cardioverter defibrillator (ICD) intervention, was significantly higher in the ASA cohort than that in the SM cohort (ASA vs SM: 10% (345/3312) vs 5% (161/3227) (RR = 1.98, 95% CI (confidence interval), 1.65-2.37; p < 0.00001, I 2 = 0%). In both groups, more than 90% of VT/VF events occurred in the early phase (during the procedure, during hospitalization or within 30 days after the procedure) (ASA: 94.20%; SM: 94.41%). Further subgroup analysis also showed that the ASA group had a higher incidence of VT/VF in both the early phase (RR = 1.94, 95% CI, 1.61-2.33; p < 0.0001, I 2 = 0%) and the late phase (RR = 2.80, 95% CI, 1.00-7.89; p = 0.05, I 2 = 33%). Furthermore, although the risks of sudden cardiac death (SCD) were similar between the ASA and SM groups, a higher incidence of sudden cardiac arrest (SCA), which included SCD and resuscitated SCA, was observed in the ASA group (RR = 2.30, 95% CI, 1.35-3.94; p = 0.002, I 2 = 0%). Conclusions: In patients with HOCM, those who received ASA showed a higher incidence of VF/VT and SCD combined with resuscitated SCA. The majority of VT/VF occurred in the early phase.

Real-world clinical outcomes of percutaneous transluminal septal myocardial ablation for patients with drug-refractory hypertrophic obstructive cardiomyopathy: results from a retrospective multicenter registry of non-high-volume centers.

Percutaneous transluminal septal myocardial ablation (PTSMA) is a well-established interventional therapy for drug-refractory hypertrophic obstructive cardiomyopathy (HOCM) as an alternative to surgical myectomy. Although guidelines recommend that PTSMA should be performed in institutions with extensive experience, it is not centralized to such high-volume centers in real-world clinical practice. Thus, this study aimed to assess the feasibility of PTSMA in non-high-volume centers. We retrospectively examined patients with HOCM who underwent PTSMA between August 2012 and May 2020 at four institutions that experienced fewer than 20 cases of PTSMA procedures. The primary clinical endpoint was a composite of safety (all-cause death, electrical defibrillation for ventricular tachycardia or fibrillation, cardiac tamponade, permanent pacemaker implantation, and repeated interventions) and efficacy endpoints (repeated interventions [PTSMA or surgical myectomy]). Fifty-eight consecutive patients were enrolled. During the 30-day follow-up, no major clinical adverse events were noted except three patients (5.2%) requiring permanent pacemaker implantation for complete atrioventricular block. The percentage of patients with New York Heart Association functional class 1 or 2 significantly increased from 8.6 to 100% (p < 0.001). In the Cox proportional hazard model, left ventricular outflow tract pressure gradient at rest ≥ 30 mmHg (hazard ratio [HR] 6.56; 95% confidence interval [CI] 1.44-29.90; p = 0.015) and mitral regurgitation grade ≥ 3 (HR 10.75; 95% CI 1.81-63.79; p = 0.009) at the 30-day follow-up were associated with a composite of major clinical adverse events. The current study demonstrated that 58 patients who underwent PTSMA in non-high-volume centers had favorable 30-day clinical outcomes, with a primary composite endpoint rate of 5.2%. A prospective study with a larger sample size and longer follow-up is warranted to verify the safety and efficacy of PTSMA in non-high-volume centers.

2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy: Executive Summary: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines.

Aim This executive summary of the hypertrophic cardiomyopathy clinical practice guideline provides recommendations and algorithms for clinicians to diagnose and manage hypertrophic cardiomyopathy in adult and pediatric patients as well as supporting documentation to encourage their use. Methods A comprehensive literature search was conducted from January 1, 2010, to April 30, 2020, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, Agency for Healthcare Research and Quality reports, and other relevant databases. Structure Many recommendations from the earlier hypertrophic cardiomyopathy guidelines have been updated with new evidence or a better understanding of earlier evidence. This summary operationalizes the recommendations from the full guideline and presents a combination of diagnostic work-up, genetic and family screening, risk stratification approaches, lifestyle modifications, surgical and catheter interventions, and medications that constitute components of guideline directed medical therapy. For both guideline-directed medical therapy and other recommended drug treatment regimens, the reader is advised to follow dosing, contraindications and drug-drug interactions based on product insert materials.

Hypertrophic Cardiomyopathy 2020.

PURPOSE OF REVIEW: To briefly review the pathophysiology and natural history of hypertrophic cardiomyopathy (HCM) and to describe the diagnosis, assessment, and contemporary management strategies. RECENT FINDINGS: HCM-related mortality remains low; however, symptoms due in large part to LVOT obstruction remain a clinical dilemma. Several medical therapies have been shown to reduce symptoms and improve functional capacity, including several recent phase 2 clinical trials involving the novel myosin modulator mavacamten. In patients with refractory symptoms, septal reduction therapy or advanced therapies remain viable options in many cases. HCM is a complex and heterogeneous disease with diverse presentations and variable anatomy and clinical outcomes. The majority of patients will remain asymptomatic or with minimal symptoms and long-term survival remains high. For symptomatic patients, a variety of medical therapies, along with septal reduction therapies, have been shown to reduce symptoms and improve functional capacity.

Septal reduction therapy using nonalcohol agent in hypertrophic obstructive cardiomyopathy: Single center experience.

AIMS: Percutaneous septal reduction therapy by either alcohol or nonalcohol agents is an alternative approach to surgery in drug-refractory symptomatic patients with hypertrophic obstructive cardiomyopathy (HOCM). Nonalcohol agents have some advantages and disadvantages over alcohol during the procedure. Nowadays, a novel non-alcohol agent, named as Ethylene-vinyl alcohol (EVOH) copolymer (Onyx® and Squid® ), is used during septal ablation. Thus, in this study, we aimed to evaluate both acute and long-term efficacy and safety profile of EVOH during septal ablation in HOCM. METHODS AND RESULTS: A total of 25 patients (52% female; mean age: 55.8 ± 17.1 years) with symptomatic HOCM were enrolled in the study. All subjects underwent clinical and laboratory assessment before and after the procedure. Peak left ventricular outflow tract (LVOT) gradient was significantly reduced just after the procedure (68 vs. 20 mmHg; P < 0.001). Peak serum creatine kinase-myocardial band and troponin I levels were 112 (35-282) ng/ml and 11 (4-93) ng/ml. EVOH embolization to diagonal artery was observed in 1 patient (4%) and the complete atrioventricular block was noted in 2 (8%) patients. During the 12-month follow-up, there was no mortality. There was a significant improvement in New York Heart Association functional class of the subjects P < 0.001). Both interventricular septum thickness and LVOT gradient showed a significant reduction during follow-up (P < 0.05). However, there was no reduction in the LVOT gradient of 3 patients (12%). CONCLUSIONS: In conclusion, our small-sized preliminary study results showed that septal reduction therapy using EVOH is an effective alternative option in reducing symptoms and LVOT gradient in HOCM.

Contemporary Septal Reduction Therapy in Drug-Refractory Hypertrophic Obstructive Cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is a complex and relatively common genetic cardiac disease that has been the subject of intense investigation for over 50 years. Most patients with HCM are asymptomatic, but some develop symptoms, often many years after the appearance of electrocardiographic or echocardiographic evidence of left ventricular hypertrophy. Symptoms due to the left ventricular outflow tract obstruction frequently worsen over time, requiring septal reduction therapy (SRT) despite optimal medical therapy. Percutaneous transluminal septal myocardial ablation (PTSMA) and surgical myectomy are collectively known as SRT. In this review, we will focus on the emerging concept and practical implication of SRT and the available evidence on either PTSMA or surgical myectomy in the literature.

Clinical benefits of a specialised clinic for hypertrophic cardiomyopathy.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is the most common monogenic cardiac condition, with a range of investigation and management options available. Recent research has recommended management within multidisciplinary-dedicated HCM centres. AIM: To assess the clinical impact of attendance at a specialised clinic on the management of HCM. METHODS: A retrospective study of patients attending the HCM Clinic @ The Alfred during the first 2 years of operation was performed. Outcome measures comprised improvements in management of HCM as a result of attending the clinic including risk stratification and further investigations, medication changes, referral for implantable cardioverter-defibrillators (ICD) and septal reduction therapy, and screening of first-degree relatives (FDR). RESULTS: Following specialised clinic attendance, there was an increase in patients investigated with 24-h Holter monitoring by 39%, stress echocardiography by 21% and cardiac magnetic resonance imaging by 70%. Medications were optimised in 47% of patients. Six per cent of patients underwent ICD implantation and 13% underwent septal myectomy. Seventy new FDR were screened identifying 10 new cases of HCM. CONCLUSIONS: Attendance at our specialised HCM clinic leads to facilitation of cardiac investigations, optimisation of medical therapy, streamlining of referrals for ICD implantation and septal reduction therapy, and improved family screening. Referral to a specialised clinic offering comprehensive management should be considered for all patients with HCM.

Surgical myectomy improves pulmonary hypertension in obstructive hypertrophic cardiomyopathy.

AIMS: Characterization of pulmonary hypertension (PH) and the effects of myectomy in hypertrophic cardiomyopathy (HCM) remain poorly defined. The aim of the study was to investigate the effect of myectomy on PH in HCM. METHODS AND RESULTS: This is a retrospective analysis of 306 consecutive symptomatic HCM patients (70% NYHA class III-IV) with evaluation of echocardiographic right ventricular systolic pressure (RVSP) both preceding (median 3 days) and following (median 4 days) myectomy. Compared with patients without PH (RVSP <35 mmHg, n = 145, 47%), patients with moderate or severe PH (RVSP ≥50 mmHg, n = 51, 17%) were older, predominantly female, had a greater prevalence of atrial fibrillation, higher natriuretic peptide levels, higher left ventricular outflow tract gradient, higher E velocity, and larger left atria. Reduction of RVSP post-myectomy was evident in patients with moderate or severe PH [59 (IQR 54-71) to 50 (IQR 39-62) mmHg, P < 0.0001] and in all patients with PH [RVSP ≥ 35 mmHg, n = 161, 43 (IQR 39-54) to 41 (IQR 35-52) mmHg, P < 0.0001]. In a subgroup of patients with long-term data, PH continued to decline during follow-up. Clinical variables associated with improvement in PH in these patients were higher left atrial volume index (R = 0.43, P = 0.0069) and moderate or severe mitral regurgitation (R = 0.33, P = 0.038). CONCLUSION: Surgical myectomy is associated with improvement in PH, most pronounced in moderate or severe PH. These data provide insight into pulmonary haemodynamics following obstruction relief and can help to guide therapeutic expectations.

A Multicenter Evaluation of the Impact of Therapies on Deep Learning-based Electrocardiographic Hypertrophic Cardiomyopathy Markers.

Background: Artificial intelligence-enhanced electrocardiography (AI-ECG) can identify hypertrophic cardiomyopathy (HCM) on 12-lead ECGs and offers a novel way to monitor treatment response. While the surgical or percutaneous reduction of the interventricular septum (SRT) represented initial HCM therapies, mavacamten offers an oral alternative. Objective: To evaluate biological response to SRT and mavacamten. Methods: We applied an AI-ECG model for HCM detection to ECG images from patients who underwent SRT across three sites: Yale New Haven Health System (YNHHS), Cleveland Clinic Foundation (CCF), and Atlantic Health System (AHS); and to ECG images from patients receiving mavacamten at YNHHS. Results: A total of 70 patients underwent SRT at YNHHS, 100 at CCF, and 145 at AHS. At YNHHS, there was no significant change in the AI-ECG HCM score before versus after SRT (pre-SRT: median 0.55 [IQR 0.24-0.77] vs post-SRT: 0.59 [0.40-0.75]). The AI-ECG HCM scores also did not improve post SRT at CCF (0.61 [0.32-0.79] vs 0.69 [0.52-0.79]) and AHS (0.52 [0.35-0.69] vs 0.61 [0.49-0.70]). Among 36 YNHHS patients on mavacamten therapy, the median AI-ECG score before starting mavacamten was 0.41 (0.22-0.77), which decreased significantly to 0.28 (0.11-0.50, p <0.001 by Wilcoxon signed-rank test) at the end of a median follow-up period of 237 days. Conclusions: The lack of improvement in AI-based HCM score with SRT, in contrast to a significant decrease with mavacamten, suggests the potential role of AI-ECG for serial monitoring of pathophysiological improvement in HCM at the point-of-care using ECG images.

Promising therapies for adults with symptomatic obstructive hypertrophic cardiomyopathy: 2023 and beyond.

INTRODUCTION: Hypertrophic cardiomyopathy (HCM) is a heterogeneous genetic heart disease with an estimated prevalence in the general population of 0.2% to 0.6%. Clinically, HCM can range from no symptoms to severe symptoms such as heart failure or sudden cardiac death. Currently, the management of HCM involves lifestyle modifications, familial screening, genetic counseling, pharmacotherapy to manage symptoms, sudden cardiac death risk assessment, septal reduction therapy, and heart transplantation for specific patients. Multicenter randomized controlled trials have only recently explored the potential of cardiac myosin inhibitors (CMIs) such as mavacamten as a directed pharmacological approach for managing HCM. AREAS COVERED: We will assess the existing medical treatments for HCM: beta-blockers, calcium channel blockers, disopyramide, and different CMIs. We will also discuss future HCM pharmacotherapy guidelines and underline this patient population's unfulfilled needs. EXPERT OPINION: Mavacamten is the first-in-class CMI approved by the FDA to target HCM pathophysiology specifically. Mavacamten should be incorporated into the standard therapy for oHCM in case of symptom persistence despite using maximally tolerated beta blockers and/or calcium channel blockers. Potential drug-drug interactions should be assessed before initiating this drug. More studies are needed on the use of CMIs in patients with kidney and/or liver failure and pregnant/breastfeeding patients.

A novel method for septal reduction therapy by three-dimensional guided transvenous intraseptal pulsed-field ablation.

BACKGROUND: Pulsed-field ablation (PFA) is a nonthermal method for achieving selective cell death with little inflammation response. However, there are no reports of PFA for septal reduction therapy (SRT). OBJECTIVE: The purpose of this study was to investigate the effectiveness and safety of PFA for SRT. METHODS: A novel transvenous intraseptal PFA method with 3-dimensional (3D) guidance was introduced in Yorkshire pigs. Electrocardiographic parameters, transthoracic echocardiography, and histopathology were used to evaluated. RESULTS: The maximum injury diameter of intramyocardial PFA increased with electric field intensity. After PFA, bipolar electrogram amplitude and pacing threshold measured by the PFA electrodes significantly decreased (F = 6.945, P = .007) or increased (F = 5.842, P = .024), respectively. In the ablated septal region, motion amplitude and systolic wall thickening rate significantly decreased and remained at low levels (motion amplitude: F = 20.793, P = .000; systolic wall thickening rate: F = 14.343, P = .000); however, septal thickness did not significantly change after PFA (F = 1.503, P = .248). Histologic examination showed specific cardiomyocyte death with gradually increased hyperchromatic cytoplasm and nuclear pyknosis, without obvious inflammatory cell infiltration in acute phase. TUNEL stain for fragmented DNA showed extensively positive in the ablation region 24 hours after PFA. During PFA, no sustained ventricular arrhythmia or atrioventricular conduction block occurred. CONCLUSION: A novel intraseptal PFA method with 3D guidance was described. Intraseptal PFA resulted in effective myocardial injury and local hypokinesis without significant acute edema. Histologic examination showed widely programmed cardiomyocyte death with little inflammatory cell infiltration.

Morphological anomalies in obstructive hypertrophic cardiomyopathy: Insights from four-dimensional computed tomography and surgical correlation.

Hypertrophic cardiomyopathy (HCM) is a genetic disorder in which left ventricular outflow tract obstruction critically affects symptoms and prognosis. Traditionally, left ventricular outflow tract obstruction was primarily attributed to septal hypertrophy with systolic anterior motion of the mitral valve. However, recent evidence highlights significant contributions from the mitral valve and papillary muscle anomalies, as well as an apical-basal muscle bundle observed in HCM patients. Accurate morphological assessment is essential when considering septal reduction therapy. While transesophageal echocardiography and cardiac magnetic resonance are recommended for assessing the anomalous structures, four-dimensional computed tomography offers superior spatial resolution and multiplanar reconstruction capabilities. These features enable the evaluation of details of the morphological anomalies, such as the apical-basal muscle band, papillary muscle anomalies, subaortic stenosis, and right ventricular outflow tract obstruction. Based on the detailed assessment of these morphological features, four-dimensional computed tomography has been utilized for planning of surgical correction in a comprehensive HCM center. This approach facilitates the intervention strategies and may improve outcomes in septal reduction therapy for obstructive HCM.

Transcatheter Myotomy to Reduce Left Ventricular Outflow Obstruction.

BACKGROUND: Left ventricular outflow tract (LVOT) obstruction is a source of morbidity in hypertrophic cardiomyopathy (HCM) and a life-threatening complication of transcatheter mitral valve replacement (TMVR) and transcatheter aortic valve replacement (TAVR). Available surgical and transcatheter approaches are limited by high surgical risk, unsuitable septal perforators, and heart block requiring permanent pacemakers. OBJECTIVES: The authors report the initial experience of a novel transcatheter electrosurgical procedure developed to mimic surgical myotomy. METHODS: We used septal scoring along midline endocardium (SESAME) to treat patients, on a compassionate basis, with symptomatic LVOT obstruction or to create space to facilitate TMVR or TAVR. RESULTS: In this single-center retrospective study between 2021 and 2023, 76 patients underwent SESAME. In total, 11 (14%) had classic HCM, and the remainder underwent SESAME to facilitate TMVR or TAVR. All had technically successful SESAME myocardial laceration. Measures to predict post-TMVR LVOT significantly improved (neo-LVOT 42 mm2 [Q1-Q3: 7-117 mm2] to 170 mm2 [Q1-Q3: 95-265 mm2]; P < 0.001; skirt-neo-LVOT 169 mm2 [Q1-Q3: 153-193 mm2] to 214 mm2 [Q1-Q3: 180-262 mm2]; P < 0.001). Among patients with HCM, SESAME significantly decreased invasive LVOT gradients (resting: 54 mm Hg [Q1-Q3: 40-70 mm Hg] to 29 mm Hg [Q1-Q3: 12-36 mm Hg]; P = 0.023; provoked 146 mm Hg [Q1-Q3: 100-180 mm Hg] to 85 mm Hg [Q1-Q3: 40-120 mm Hg]; P = 0.076). A total of 74 (97.4%) survived the procedure. Five experienced 3 of 76 (3.9%) iatrogenic ventricular septal defects that did not require repair and 3 of 76 (3.9%) ventricular free wall perforations. Neither occurred in patients treated for HCM. Permanent pacemakers were required in 4 of 76 (5.3%), including 2 after concomitant TAVR. Lacerations were stable and did not propagate after SESAME (remaining septum: 5.9 ± 3.3 mm to 6.1 ± 3.2 mm; P = 0.8). CONCLUSIONS: With further experience, SESAME may benefit patients requiring septal reduction therapy for obstructive hypertrophic cardiomyopathy as well as those with LVOT obstruction after heart valve replacement, and/or can help facilitate transcatheter valve implantation.

Outcomes of surgical septal myectomy for obstructive hypertrophic cardiomyopathy after previous septal reduction therapy.

OBJECTIVE: To compare early and late outcomes of septal myectomy in patients with obstructive hypertrophic cardiomyopathy who presented with residual or recurrent left ventricular outflow tract (LVOT) obstruction after previous septal-reduction therapy (SRT). METHODS: From January 1989 to March 2022, 145 patients underwent reintervention by septal myectomy for residual LVOT obstruction after previous SRT; 72 patients had previous alcohol septal ablation (ASA) and 73 had previous surgical septal myectomy. Baseline patient characteristics, echocardiographic parameters, and surgical outcomes were compared between these 2 groups. RESULTS: Patients who had previous ASA were more likely to be male (50.0% vs 30.1%; P = .015), be older (median age 57.5 years vs 48.3 years; P < .001), and have a greater body mass index (32.7 kg/m2 vs 30.0 kg/m2; P = .011). After repeat SRT by septal myectomy, there was no significant difference in the incidence of postoperative complete heart block, necessitating permanent pacemaker, between the 2 groups (8.3% vs 2.7%; P = .151). One (0.7%) patient died within 30 days of surgery. Over a median follow-up of 7.5 years (interquartile range, 3.0-13.8), there were 20 deaths. Kaplan-Meier 5-, 10-, and 15-year survival rates were 100%, 91%, and 76% for the previous septal myectomy group, and 93%, 81%, and 64% for the previous ASA group (P = .207). CONCLUSIONS: Septal myectomy for residual or recurrent LVOT obstruction in patients who had previous ASA is safe, with an acceptably low rate of postoperative complete heart block. Surgical outcomes and late survival rates in patients with complete heart block ASA were satisfactory and comparable with patients who underwent repeat myectomy.

2024 AHA/ACC/AMSSM/HRS/PACES/SCMR Guideline for the Management of Hypertrophic Cardiomyopathy: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines.

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.

Effects of septal myectomy on left atrial and left ventricular function in obstructive hypertrophic cardiomyopathy.

AIMS: Mechanical function of the left atrium (LA) and the left ventricle (LV) has been demonstrated to be a prognostic factor in patients with hypertrophic cardiomyopathy (HCM). We explore whether myocardial mechanical function can be improved by septal reduction therapy in symptomatic obstructive HCM. METHODS AND RESULTS: Among 65 patients who underwent septal myectomy for symptomatic obstructive HCM from 2006 to 2022, 44 were analysed after excluding those who underwent simultaneous valve repair or replacement or maze operation. LA and LV functional variables including LA strain and LV global longitudinal strain were evaluated by two-dimensional and speckle-tracking echocardiography and compared before and 1 year after surgery. After septal myectomy, LA volume index (58.1 ± 18.3 vs. 45.3 ± 14.6 mL/m2 , P = 0.001) decreased significantly. As LV end-systolic dimension increased after surgery, the LV ejection fraction decreased (73.8 ± 6.7 vs. 62.9 ± 8.3%, P < 0.001). LA strain (24.4 ± 9.3 vs. 30.5 ± 13.6%, P = 0.004) improved after septal myectomy, but LV global longitudinal strain deteriorated (-12.6 ± 3.6 vs. -11.6 ± 4.3%, P = 0.033), mainly related to worsening non-septal longitudinal strain (-14.4 ± 4.3 vs. -10.9 ± 8.4%, P = 0.005). CONCLUSIONS: As haemodynamic loads due to LV outflow tract obstruction was relieved through surgical septal reduction therapy in patients with symptomatic obstructive HCM, there was a significant reduction in LA volume and restoration of LA mechanical dysfunction. However, LV mechanical dysfunction deteriorated even after surgical septal reduction therapy.

Mavacamten, an Alternative to Septal Reduction Therapy for Patients with Hypertrophic Cardiomyopathy.

Hypertrophic cardiomyopathy (HCM) is a common heridetary cardiac disorder characterized by a wide range of symptoms. The pharmacological treatment of HCM is currently limited to beta blockers, non-dihydropyridine calcium channel blockers and disopyramide. Mavacamten is a novel cardiac myosin inhibitor, which was recently added to the limited pharmacological list of treatment options for HCM. This editorial elaborates on current evidence evaluating the use of mavacamten in patients with symptomatic obstructive HCM, comments on its current use and its expanded potential applications in the future.