Transesophageal Doppler echocardiography in obstructive hypertrophic cardiomyopathy: clarification of pathophysiology and importance in intraoperative decision making

Systolic anterior motion-mediated mitral regurgitation and surgical management in hypertrophic obstructive cardiomyopathy

Mitral regurgitation mediated by systolic anterior motion is a typical manifestation in patients with hypertrophic obstructive cardiomyopathy. Although septal myectomy is currently the preferred treatment for patients with drug-refractory hypertrophic obstructive cardiomyopathy, surgical management of associated mitral regurgitation remains controversial. Whether septal myectomy alone or additional valve procedures are required to correct significant mitral regurgitation depends largely on the pathophysiology of each individual. For intervention purposes, it is important to identify the real systolic anterior motion-mediated mitral regurgitation and clarify the mitral structural abnormalities, as well as the other conditions, which may indicate the degree of mitral valve competence. As a first-line imaging modality in the management of hypertrophic cardiomyopathy, echocardiography could provide crucial information for surgical decision making. In this article, we focus on elucidating the typical echocardiographic features of systolic anterior motion-mediated mitral regurgitation and offer an assessment process to determine other contributors to obstruction and mitral regurgitation. Additionally, guidance for surgical decision making for mitral regurgitation in patients with hypertrophic obstructive cardiomyopathy is discussed.

Three-Dimensional Heart Modeling of Hypertrophic Obstructive Cardiomyopathy for In Situ Patient-Specific Simulation to Optimize Septal Myectomy

OBJECTIVE

Hypertrophic obstructive cardiomyopathy (HOCM) develops in at least 1 out of 715 young adults. Patients who are refractory to medical therapy qualify for septal myectomy. Due to anatomy, serious complications such as ventricular septal defect and heart block may occur. Establishing cardiovascular magnetic resonance (CMR)-based 3-dimensional (3D) models as part of preoperative planning and training has the potential to decrease procedure-related complications and improve results.

METHODS

CMR images were used to segment cardiac structures. Left ventricular wall thickness was calculated and projected on top of the in silico model. A 3D model was printed with a red layer indicating a wall thickness exceeding 15 mm and used for preoperative resection planning and patient counseling. To provide preoperative patient-specific in situ simulation, the planned resection volume was replaced with silicone in a second model. For perioperative quality control, resected silicone was compared with resected myocardial tissue. The impact of the models was evaluated descriptively through consultation of both the cardiothoracic surgeon and patients and through patient outcomes.

RESULTS

Three-dimensional in silico and 3D-printed heart models of 5 patients were established preoperatively. Since the introduction of the models in October 2020, the surgeon feels better prepared, more confident, and less difficulty with making decisions. In addition, patients feel better informed preoperatively.

CONCLUSIONS

Using 3D heart models optimized preoperative planning and training, intraoperative quality control, and patient consultation. Reduction of procedure-related complications and clinical outcome should be studied in larger cohorts.

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.

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.

Hypertrophic cardiomyopathy with anteriorly directed mitral regurgitation is a red flag for concomitant pathology: a case report

Background

Hypertrophic cardiomyopathy (HCM) is often linked to systolic anterior motion (SAM) of the mitral valve, typically resulting in a posteriorly directed mitral regurgitation (MR) jet. An anteriorly directed MR jet suggests additional mitral valve pathology that may not be resolved by myectomy alone.

Case summary

A 58-year-old construction worker with no significant medical history experienced a syncopal event and was admitted to the emergency department with acute pulmonary oedema. A systolic murmur was investigated with a trans-thoracic echocardiogram that revealed severe MR with an unusual anteriorly directed MR jet and a possible flail segment of the posterior leaflet. This finding was further characterized with a trans-oesophageal echocardiogram that revealed severe asymmetric septal hypertrophy with SAM of the mitral valve, severe mitral regurgitation into a dilated left atrium with pulmonary vein flow reversal not caused by HCM-associated SAM, and a markedly abnormal mitral valve with flail and prolapse. The patient underwent successful cardiac surgery, including mitral valve repair and septal myectomy. The patient's recovery was uneventful, allowing for a return to work within a month post-surgery.

Discussion

The anteriorly directed MR jet served as a red flag, leading to the discovery of an independent mitral valve pathology that required surgical intervention beyond the expected treatment for SAM-associated HCM. This case highlights the complexity of assessing MR in patients with HCM and underscores the importance of characterizing MR jet direction in diagnosing additional mitral valve diseases.

Treatment Strategies for Hypertrophic Cardiomyopathy: Surgical

Septal myectomy is a well-established procedure for septal reduction in patients with obstructive hypertrophic cardiomyopathy (HCM) who have not responded to medical treatment. The surgical approach is tailored to the unique pathophysiology and septal morphology of the patient. Extended transaortic myectomy is the standard procedure for patients with isolated subaortic obstruction, the most common type of HCM. However, transapical myectomy is a useful adjunct for patients with long or midventricular obstruction and is our preferred technique for ventricular enlargement in patients with severe symptomatic diastolic heart failure because of extensive apical hypertrophy. Septal myectomy provides excellent postoperative outcomes as regards symptom relief and functional improvement, and operative morbidity and mortality rates are low in experienced centers. This article summarizes our current surgical management of patients with HCM and details operative methods and outcomes.

Imaging in Hypertrophic Cardiomyopathy: Beyond Risk Stratification

A multimodality imaging evaluation in hypertrophic cardiomyopathy is often used for risk stratification. Recent developments in imaging have allowed for better diagnosis, prognosis, and decision-making for a variety of therapies from medical to interventional. Echocardiography and magnetic resonance have been integral in evaluating subtype, left ventricular function, tissue characterization, left atrial measurements, valvular function, and presence of left ventricular aneurysm and outflow tract obstruction. These factors have helped to quantify risk of atrial fibrillation and determine the likely usefulness of pharmacologic therapy and septal reduction therapy. This review covers these in detail.

Is Congenital Muscular Mitral-Aortic Discontinuity Another Feature of Obstructive Hypertrophic Cardiomyopathy? A Pathology Validation Study

Hypertrophic cardiomyopathy (HCM) is an inherited myocardial disease at risk of sudden cardiac death and heart failure, even requiring heart transplantation. A "muscular mitral-aortic discontinuity" has been reported during surgery in the obstructive form. We aimed to validate these findings through pathological analysis of HCM heart specimens from the cardiovascular pathology tissue registry. Hearts with septal asymmetric HCM from sudden cardiac death, other causes of death, or heart transplantation were included. Sex-matched and age-matched patients without HCM served as controls. Gross and histologic analysis of the mitral valve (MV) apparatus and the mitral-aortic continuity were performed. Thirty HCM hearts (median age, 29.5 years; 15 men) and 30 controls (median age, 30.5 years; 15 men) were studied. In HCM hearts, a septal bulging was present in 80%, an endocardial fibrous plaque in 63%, a thickening of the anterior MV leaflet in 56.7%, and an anomalous insertion of papillary muscle in 10%. All cases but 1 (97%) revealed a myocardial layer overlapping the mitral-aortic fibrous continuity on the posterior side, corresponding to the left atrial myocardium. A negative correlation between the length of this myocardial layer and the age and the anterior MV leaflet length was found. The length did not differ between HCM and controls. Pathologic study of obstructive HCM hearts does not confirm the existence of a "muscular mitral-aortic discontinuity". An extension of left atrial myocardium, overlapping posteriorly the intervalvular fibrosa, is rather visible, and its length decreases with age, possibly as a consequence of left atrial remodeling. Our study highlights the fundamental role of thorough gross examination and the value of organ retention for further analysis in order to validate new surgical and imaging findings.

Metoprolol or Verapamil in the Management of Patients With Hypertrophic Cardiomyopathy: A Systematic Review

Hypertrophic cardiomyopathy (HCM) is the most common genetic heart disease and is a prevalent cause of sudden cardiac death (SCD). This study aims to establish the benefits and therapeutic value metoprolol or verapamil offer to patients who suffer from symptoms caused by HCM, with regard to resolving left ventricular outflow tract obstruction (LVOTO), as well as improving a patient's quality of life and reducing symptoms. We conducted a systematic review to find clinical studies that described the use of metoprolol or verapamil in the management of HCM. Three databases were analyzed for studies, PubMed, Google Scholar, and ScienceDirect. We discovered 6,260 potentially eligible records across all the databases. According to our eligibility criteria, we included four studies in this review. Metoprolol showed median left ventricular outflow tract (LVOT) gradients of 25 mm Hg versus 72 mm Hg (P = 0.007) at rest, 28 mm Hg versus 62 mm Hg (P < 0.001) at peak exercise, and 45 mm Hg versus 115 mm Hg (P < 0.001) post-exercise. Verapamil also showed a statistically significant increase in exercise capacity. Both drugs have been shown to be safe to use with a good side effect profile; however, metoprolol was better tolerated in the patient population that was tested in the studies collected. In this study, metoprolol was effective in reducing LVOT and improving the quality of life in patients, while verapamil showed variable effects on both exercise capacity and baseline hemodynamics.

Prognostic Implication of Mitral Valve Disease and Its Progression in East Asian Patients With Hypertrophic Cardiomyopathy

Background Hypertrophic cardiomyopathy (HCM) is a genetic disorder affecting not only the myocardium but also the mitral valve (MV) and its apparatus. This study aimed to investigate the prognostic implication of MV disease and its progression in East Asian patients with HCM. Methods and Results We assessed MV structure and function on the indexed echocardiogram of 1185 patients with HCM (mean±SD age, 60±14 years; men, 67%) in a longitudinal HCM registry, and 667 patients who performed follow-up echocardiogram after 3 to 5 years were also analyzed. Progression of mitral regurgitation (MR) was defined as the increase of at least 1 grade. Clinical outcomes were defined as a composite of cardiovascular death, heart failure hospitalization, MV surgery or septal myectomy, and heart transplantation. Most of the entire cohort was nonobstructive type (n=1081 [91.2%]). A total of 278 patients (23.5%) showed at least mild MR on indexed echocardiogram. MR, systolic anterior motion, and mitral annular calcification were more prevalent in patients with obstructive HCM. During 7.0±4.0 years of follow-up, presence of MR was independently associated with poor clinical outcomes (hazard ratio [HR], 1.60 [95% CI, 1.07-2.40]; P=0.023). On follow-up echocardiogram, 67 (10.0%) patients showed MR progression, and it was independently associated with poor prognosis (HR, 2.46 [95% CI, 1.29-4.71]; P=0.007). Conclusions In East Asian patients with HCM whose major type is nonobstructive, MV disease is common. MR, systolic anterior motion, and mitral annular calcification are more prevalent in patients with obstructive HCM. The presence and progression of MR are associated with a poor prognosis in patients with HCM.

Ventricular Septal Myectomy for Obstructive Hypertrophic Cardiomyopathy (Analysis Spanning 60 Years Of Practice): AJC Expert Panel

Surgical myectomy remains the time-honored primary treatment for hypertrophic cardiomyopathy patients with drug refractory limiting symptoms due to LV outflow obstruction. Based on >50 years experience, surgery reliably reverses disabling heart failure by permanently abolishing mechanical outflow impedance and mitral regurgitation, with normalization of LV pressures and preserved systolic function. A consortium of 10 international currently active myectomy centers report about 11,000 operations, increasing significantly in number over the most recent 15 years. Performed in experienced multidisciplinary institutions, perioperative mortality for myectomy has declined to 0.6%, becoming one of the safest currently performed open-heart procedures. Extended myectomy relieves symptoms in >90% of patients by ≥ 1 NYHA functional class, returning most to normal daily activity, and also with a long-term survival benefit; concomitant Cox-Maze procedure can reduce the number of atrial fibrillation episodes. Surgery, preferably performed in high volume clinical environments, continues to flourish as a guideline-based and preferred high benefit: low treatment risk option for adults and children with drug refractory disabling symptoms from obstruction, despite prior challenges: higher operative mortality/skepticism in 1960s/1970s; dual-chamber pacing in 1990s, alcohol ablation in 2000s, and now introduction of strong negative inotropic drugs potentially useful for symptom management.

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

Background and Objective

The prevalence of hypertrophic cardiomyopathy (HCM) is estimated to be 1 in 200 to 500 individuals, with systolic anterior motion (SAM) of the mitral valve (MV) and left ventricular outflow tract (LVOT) obstruction present in 60% to 70%. In this narrative review, we aim to elucidate the pathophysiology of SAM-septal contact and LVOT obstruction in HCM by presenting a detailed review on the anatomy of the MV apparatus in HCM, examining the various existing theories pertaining to the SAM phenomenon as supported by cardiac imaging, and providing a critical assessment of management strategies for SAM in HCM.

Methods

A literature review was performed using PubMed, EMBASE, Ovid, and the Cochrane Library, of all scientific articles published through December 2021. A focus was placed on descriptive studies, reports correlating echocardiographic findings with pathologic diagnosis, and outcomes studies.

Key Content and Findings

The pathophysiology of SAM involves the complex interplay between HCM morphology, MV apparatus anatomic abnormalities, and labile hemodynamic derangements. Echocardiography and cardiac magnetic resonance (CMR) vector flow mapping have identified drag forces, as opposed to the "Venturi effect", as the main hydraulic forces responsible for SAM. The degree of mitral regurgitation with SAM is variable, and its severity is correlated with degree of LVOT obstruction and outcomes. First line therapy for the amelioration of SAM and LVOT obstruction is medical therapy with beta-blockers, non-dihydropyridine calcium-channel blockers, and disopyramide, in conjunction with lifestyle modifications. In refractory cases septal reduction therapy is performed, which may be combined with a 'resect-plicate-release' procedure, anterior mitral leaflet extension, surgical edge-to-edge MV repair, anterior mitral leaflet retention plasty, or secondary chordal cutting.

Conclusions

Recent scientific advances in the field of HCM have allowed for a maturation of our understanding of the SAM phenomenon. Cardiac imaging plays a critical role in its diagnosis, treatment, and surveillance, and in our ability to apply the appropriate therapeutic regimens. The increasing prevalence of HCM places an emphasis on continued basic and clinical research to further improve outcomes for this challenging population.

Perioperative Implications of the 2020 American Heart Association/American College of Cardiology Guidelines for the Diagnosis and Treatment of Patients with Hypertrophic Cardiomyopathy: A Focused Review

Hypertrophic cardiomyopathy is a complex disease with significant implications for patients and the physicians called upon to care for them during the perioperative period. In this article, the 2020 American Heart Association and American College of Cardiology clinical practice guidelines for the evaluation and management of pediatric and adult patients with hypertrophic cardiomyopathy are reviewed, with a particular focus on perioperative considerations for the anesthesiologist.

Mitral Valve Cleft-like Indentations in Hypertrophic Obstructive Cardiomyopathy: Insights From Intraoperative Three-Dimensional Transesophageal Echocardiography

OBJECTIVES

Cleft-like indentations (CLIs) of the mitral valve (MV) are best assessed with three-dimensional (3D) transesophageal echocardiography (TEE). The present study examined the prevalence, characteristics, and surgical effect of MV CLIs in patients with hypertrophic cardiomyopathy (HCM).

DESIGN

Prospective, observational, case-control study.

SETTING

Tertiary medical center.

PARTICIPANTS

The study comprised 90 patients with HCM undergoing myectomy and 59 patients undergoing cardiac surgery for non-MV related indications.

MEASUREMENTS AND MAIN RESULTS

Intraoperative 3D TEE was used to evaluate the presence and characteristics of MV CLIs compared, with a random control group of 59 patients undergoing cardiac surgery for non-MV related indications. Ninety patients with HCM (mean age 54.8 ± 13.3 y, 67.8% male) were compared with 59 control patients (mean age 67 ± 12.7 y, 79.7% male). Three-dimensional TEE images were interpreted by consensus of two experienced echocardiographers. At least one MV CLI was present in 84 patients with HCM (93.3%), compared with 23 control patients (39%; p < 0.01). Compared with control patients, patients with HCM were more likely to have deep MV CLIs (85.6% v 25.4%; p < 0.01) and ≥2 CLIs (52.2% v 26.1%; p = 0.02). Six HCM patients (7%) appeared to have true congenital posterior leaflet clefts versus 0% in control patients (p = 0.08). Preoperative mitral regurgitation severity and jet direction were not associated with the presence of deep or multiple MV CLIs (all p > 0.2). None of the MV CLIs in the HCM group required MV surgical intervention or second pump runs for MV regurgitation correction after myectomy.

CONCLUSION

Deep and multiple MV CLIs are common in patients with HCM undergoing septal myectomy, including possible true posterior clefts, but they are not associated with the premyectomy severity of mitral regurgitation or jet direction, and do not result in surgical MV intervention.

4D flow MRI left atrial kinetic energy in hypertrophic cardiomyopathy is associated with mitral regurgitation and left ventricular outflow tract obstruction

To noninvasively assess left atrial (LA) kinetic energy (KE) in hypertrophic cardiomyopathy (HCM) patients using 4D flow MRI and evaluate coupling associations with mitral regurgitation (MR) and left ventricular outflow tract (LVOT) obstruction. Twenty-nine retrospectively identified patients with HCM underwent 4D flow MRI. MRI-estimated peak LVOT pressure gradient (∆P_MRI) was used to classify patients into non-obstructive and obstructive HCM. Time-resolved volumetric LA kinetic energy (KE_LA) was computed throughout systole. Average systolic (KE_LA-avg) and peak systolic (KE_LA-peak) KE_LA were compared between non-obstructive and obstructive HCM groups, and associations to MR severity and LVOT ∆P_MRI were tested.The study included 15 patients with non-obstructive HCM (58.6 [45.9, 65.2] years, 7 females) and 14 patients with obstructive HCM (51.9 [47.6, 62.6] years, 6 females). Obstructive HCM patients demonstrated significantly elevated instantaneous KE_LA over all systolic time-points compared to non-obstructive HCM (P < 0.05). Obstructive HCM patients also demonstrated higher KE_LA-avg (14.8 [10.6, 20.4] J/m³ vs. 33.4 [23.9, 61.3] J/m³, P < 0.001) and KE_LA-peak (22.1 [15.9, 28.7] J/m³ vs. 57.2 [44.5, 121.4] J/m³, P < 0.001) than non-obstructive HCM. MR severity was significantly correlated with KE_LA-avg (rho = 0.81, P < 0.001) and KE_LA-peak (rho = 0.79, P < 0.001). LVOT ∆P_MRI was strongly correlated with KE_LA metrics in obstructive HCM (KE_LA-avg: rho = 0.86, P < 0.001; KE_LA-peak: rho = 0.85, P < 0.001).In HCM patients, left atrial kinetic energy, by 4D flow MRI, is associated with MR severity and the degree of LVOT obstruction.

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.

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.

The Role of Mitral Valve in Hypertrophic Obstructive Cardiomyopathy: An Updated Review

Hypertrophic cardiomyopathy (HCM) is the most common inherited heart disease and the most common cause of sudden cardiac death in young population, especially in athletes under 35 years old. Mutations occur primarily in the β-myosin heavy chain gene and involve the cardiac myosin-binding protein C gene. In this review we would like to focus on the importance of the examination of mitral valve apparatus and the mitral valve abnormalities in patients with HCM. Abnormalities in mitral valve (elongated mitral leaflets, displacement of papillary muscles, and systolic anterior motion) may be the primary pathognomonic elements, even in the absence of hypertrophy. Echocardiography is the gold standard for the diagnosis of HCM. Magnetic resonance imaging emerges as one of the most important imaging modalities for precise diagnosis, assisting in risk stratification and treatment strategy. Mitral valve abnormalities take part fundamentally in the formation of systolic anterior motion of the mitral valve and, they have substantially been repaired surgically. Although myectomy addresses the septum reduction, obstruction relief should be maximally achieved with a potential combination of myectomy and mitral valve repair.

Markers of responsiveness to disopyramide in patients with hypertrophic cardiomyopathy

BACKGROUND

Significant left-ventricular outflow tract obstruction (LVOTO) in hypertrophic cardiomyopathy (HCM) may result in symptoms and is associated with adverse outcomes. Although disopyramide can reduce resting gradients, nearly 30% of HCM patients do not respond. We sought to study the clinical and echocardiographic variables associated with disopyramide-induced LVOT-gradient reduction.

METHODS

Forty-one disopyramide-treated HCM patients (average daily-dose 305 mg) were subdivided into two groups: (1) nineteen responders, with a reduction of LVOT-gradients of at least 30% from baseline, and (2) twenty-two non-responders, in whom LVOT-gradients did not change or increased following treatment. All patients had a thorough clinical and echocardiographic assessment pre- and post-treatment initiation.

RESULTS

Patients who responded to disopyramide had better pretreatment left ventricular (LV) systolic function (LV ejection fraction of 67.9 ± 5.6% vs. 59.7 ± 5.8%, p = 0.0001), better LV global longitudinal strain (-17.9 ± 2.3% vs. -16.1 ± 2.5%, p = 0.048), less mitral regurgitation, smaller LV size (indexed LV end-systolic volume of 16.2 ± 5.1 ml/m² vs. 23.2 ± 6.8 ml/m², p = 0.001), and lower LV maximal wall thickness (17.2±3 mm vs.19.2 ± 3.4 mm, p = 0.046). Baseline left atrial (LA) volumes were significantly lower in the responders, with higher indices of LA ejection fraction (62 ± 11.2% vs. 50.5 ± 12.2%, p = 0.005), systolic LA strain (34 ± 12.4% vs. 25.8 ± 10.6%, p = 0.04), and LA strain-rate (1.34 ± 0.49%/sec vs. 0.99 ± 0.24%/sec, p = 0.012). In multivariable analysis, the presence of reduced LV systolic function and systolic LA strain-rate remained independently associated with poor response to disopyramide.

CONCLUSIONS

Obstructive HCM patients with more severe disease at baseline tend to respond less to disopyramide treatment. In those patients, early referral for alcohol septal ablation or myectomy surgery should be considered.

Emerging pharmacologic and structural therapies for hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy is the most common inherited heart disease. Although it was first described over 50 years ago, there has been little in the way of novel disease-specific therapeutic development for these patients. Current treatment practice largely aims at symptomatic control using old drugs made for other diseases and does little to modify the disease course. Septal reduction by surgical myectomy or percutaneous alcohol septal ablation are well-established treatments for pharmacologic-refractory left ventricular outflow tract obstruction in hypertrophic cardiomyopathy patients. In recent years, there has been a relative surge in the development of innovative therapeutics, which aim to target the complex molecular pathophysiology and resulting hemodynamics that underlie hypertrophic cardiomyopathy. Herein, we review the new and emerging therapeutics for hypertrophic cardiomyopathy, which include pharmacologic attenuation of sarcomeric calcium sensitivity, allosteric inhibition of cardiac myosin, myocardial metabolic modulation, and renin-angiotensin-aldosterone system inhibition, as well as structural intervention by percutaneous mitral valve plication and endocardial radiofrequency ablation of septal hypertrophy. In conclusion, while further development of these therapeutic strategies is ongoing, they each mark a significant and promising advancement in treatment for hypertrophic cardiomyopathy patients.

The Disappearing Murmur: Systolic Anterior Motion of the Mitral Valve Leaflet in a Non-hypertrophic Cardiomyopathy Patient

Systolic anterior motion (SAM) of the mitral valve is a well-known phenomenon associated with left ventricular outflow tract obstruction and hemodynamic compromise. This finding may occur in patients with or without hypertrophic cardiomyopathy. In this report, a patient with no prior medical history presented to the hospital with left-sided chest pain and high-risk echocardiogram (ECG) findings. Left heart catheterization with coronary angiography was negative for coronary artery disease. His initial examination was significant for a systolic murmur due to the underlying SAM, as demonstrated by transthoracic echocardiogram. During his hospitalization, he developed acute heart failure syndrome as a result of dynamic outflow tract obstruction. He was treated with fluid resuscitation with a resolution of his hemodynamic compromise. On a follow-up examination, there was no murmur and SAM was no longer present on echocardiogram. This case demonstrates the importance of recognizing the clinical manifestations of SAM as well as its role in maintaining an appropriate hemodynamic status.

Assessment of the severity of native mitral valve regurgitation

Mitral regurgitation (MR) is a major cause of cardiovascular morbidity and mortality. MR is classified as primary (organic) if it is due to an intrinsic valve abnormality, or secondary (functional) if the etiology is because of remodeling of left ventricular geometry and/or valve annulus. Transthoracic echocardiography (TTE) is the initial modality for MR evaluation. Parameters used for the assessment of MR include valve structure, cardiac remodeling, and color and spectral Doppler. Quantitative measurements include effective regurgitant orifice area, regurgitant volume, and regurgitant fraction. Knowledge of advantages and limitations of echo-Doppler parameters is essential for accurate results. An integrative approach is recommended in overall grading of MR as mild, moderate, or severe since singular parameters may be affected by several factors. When the mechanism and/or grade of MR is unclear from the TTE or is discrepant with the clinical scenario, further evaluation with transesophageal echocardiography or cardiac magnetic resonance imaging is recommended, the latter emerging as a powerful MR quantitation tool.

Systolic Anterior Motion of Mitral Valve Subchordal Apparatus: A Rare Echocardiographic Pattern in Non-Obstructive Hypertrophic Cardiomyopathy

Systolic anterior motion (SAM) of the mitral valve or chordate is one characteristic seen in hypertrophic cardiomyopathy (HCM) either in obstructive or non-obstructive phenotypes. More often than not, the obstruction is caused by valvular rather than chordal SAM. We describe the role of echocardiography in identifying the actual anatomical location of the mitral valve apparatus involved in SAM and in assessing consequent left ventricular outflow tract (LVOT) obstruction in an otherwise asymptomatic patient. We report a case of a 29-year-old male admitted for an elective non-cardiac surgery, presenting with a cardiac murmur and left axis deviation with biventricular hypertrophy on electrocardiogram. On 2D transthoracic echocardiography (TTE), an asymmetrically hypertrophied left ventricle with systolic motion of anterior mitral valve was incidentally seen. Continuous wave Doppler assessment across the LVOT showed some gradient of obstruction (peak gradient: 9 mm Hg). Transesophageal echocardiography (TEE) demonstrated a redundant anterior mitral valve with the subchordal apparatus mainly causing SAM and confirmed the gradient obtained on TTE, with a mild degree, yet non-significant, degree of LVOT obstruction (mean gradient: 10 mm Hg) documented. Because of this finding, patient was cleared for surgery. Management was deemed conservative with emphasis on close surveillance for signs and symptoms attributable to development of significant LVOT obstruction in patients with HCM. To our knowledge, this is the first reported case in our country of an echocardiographic pattern of systolic anterior motion primarily of the subchordal mitral valve apparatus causing some, though non-significant, degree of LVOT obstruction in HCM. Echocardiographic features such as asymmetric left ventricular hypertrophy and presence of some LVOT obstruction caused primarily by subchordal apparatus could impact management in asymptomatic patients.

The Remarkable 50 Years of Imaging in HCM and How it Has Changed Diagnosis and Management: From M-Mode Echocardiography to CMR

The almost 50-year odyssey of cardiac imaging in hypertrophic cardiomyopathy (HCM), revisited and described here, has been remarkable, particularly when viewed in the timeline of advances that occurred during a single generation of investigators. At each step along the way, from M-mode to 2-dimensional echocardiography to Doppler imaging, and finally over the last 10 years with the emergence of high-resolution tomographic cardiac magnetic resonance (CMR), evolution of the images generated by each new technology constituted a paradigm change over what was previously available. Together, these advances have transformed the noninvasive diagnosis and management of HCM in a number of important clinical respects. These changes include a more complete definition of the phenotype, resulting in more reliable clinical identification of patients and family members, defining mechanisms (and magnitude) of left ventricular outflow obstruction, and novel myocardial tissue characterization (including in vivo detection of fibrosis/scarring); notably, these advances afford more precise recognition of at-risk patients who are potential candidates for life-saving primary prevention defibrillator therapy. This evolution in imaging as applied to HCM has indelibly changed cardiovascular practice for this morphologically and clinically complex genetic disease.

The mechanisms, diagnosis and management of mitral regurgitation in mitral valve prolapse and hypertrophic cardiomyopathy

Valvular disease is a frequent cardiac pathology leading to heart failure and, ultimately, death. Mitral regurgitation, defined as the inability of the two mitral leaflets to coapt, is a common valvular disease and a self sustained pathology. A better understanding of the mitral valve histological layers provides a better understanding of the leaflet and chordae changes in mitral valve prolapse. Mitral valve prolapse may occur in myxomatous degenerative abnormalities, connective tissue disorders or in sporadic isolated cases. It is the most common mitral abnormality of non-ischemic cause leading to severe surgery-requiring mitral regurgitation. In addition to standard echocardiographic investigations, newly implemented three-dimensional techniques are being used and they permit a better visualisation, from the so-called ‘surgical view’, and an improved evaluation of the mitral valve. Hypertrophic cardiomyopathy is the most frequent inherited myocardial disease caused by mutations in various genes encoding proteins of the cardiac sarcomere, leading to a marked left ventricular hypertrophy unexplained by other comorbidities. The pathological echocardiographic hallmarks of hypertrophic cardiomyopathy are left ventricular hypertrophy, left ventricular outflow tract obstruction and systolic anterior motion of the mitral valve. The systolic anterior motion of the mitral valve contributes to the development of mitral regurgitation and further narrows the left ventricular outflow tract, leading to more severe symptomatology. Cardiac magnetic resonance imaging accurately measures the left ventricular mass, the degree of diastolic function and it may also be used to distinguish phenotypic variants. The clinical outcome of patients with these pathologies is mostly determined by the selected option of treatment. The purpose of surgical correction regarding mitral valve involvement is to restore valvular competence. Surgery has proven to be the only useful treatment in preventing heart failure, improving symptomatology and reducing mortality. Our approach wishes to enhance the understanding of the mitral valve’s involvement in hypertrophic cardiomyopathy and mitral valve prolapse from genetic, haemodynamic and clinical perspectives, as well as to present novelties in the grand field of treatment.

Cardiovascular magnetic resonance of mitral valve length in hypertrophic cardiomyopathy

BACKGROUND

Previous data suggest that mitral valve leaflets are elongated in hypertrophic cardiomyopathy (HCM), and mitral valve leaflet elongation may constitute a primary phenotypic expression of HCM. Our objective was to measure the length of mitral valve leaflets by cardiovascular magnetic resonance (CMR) in subjects with HCM caused by a Finnish founder mutation in the myosin-binding protein C gene (MYBPC3-Q1061X), carriers of the same mutation without left ventricular hypertrophy, as well as in unselected consecutive patients with HCM, and respective controls.

METHODS

Anterior mitral valve leaflet (AML) and posterior mitral valve leaflet (PML) lengths were measured by CMR in 47 subjects with the Q1061X mutation in the gene encoding MYBPC3 and in 20 healthy relatives without the mutation. In addition, mitral valve leaflet lengths were measured by CMR in 80 consecutive non-genotyped patients with HCM in CMR and 71 age- and gender-matched healthy subjects.

RESULTS

Of the subjects with the MYBPC-Q1016X mutation, 32 had left ventricular hypertrophy (LVH, LV maximal wall thickness ≥ 13 mm in CMR) and 15 had no hypertrophy. PML was longer in patients with the MYBPC3-Q1061X mutation and LVH than in controls of the MYBPC group (12.8 ± 2.8 vs 10.6 ± 1.9 mm, P = 0.013), but the difference between the groups was not statistically significant when PML was indexed for BSA (P = 0.066), or when PML length was adjusted for BSA, age, gender, LV mass and ejection fraction (P = 0.195). There was no significant difference in the PML length in mutation carriers without LVH and controls (11.1 ± 3.4 vs 10.6 ± 1.9, P = 0.52). We found no difference in AML lengths between the MYBPC mutation carriers with or without hypertrophy and controls. In 80 consecutive non-genotyped patients with HCM, there was no difference either in AML or PML lengths in subjects with HCM compared to respective control subjects.

CONCLUSIONS

In subjects with HCM caused by the Q1061X mutation in the MYBPC3 gene, the posterior mitral valve leaflets may be elongated, but mitral valve elongation does not constitute primary phenotypic expression of the disease. Instead, elongated mitral valve leaflets seem to be associated with body size and left ventricular remodeling.

Conservative approach to mitral valve replacement in hypertrophic cardiomyopathy with systolic anterior motion - a case report

The authors report the case of a 60-year-old patient with hypertrophic cardiomyopathy (HCM), systolic anterior motion (SAM), and high gradient in the left ventricular outflow tract (LVOT) who underwent surgical treatment. During the surgery, myomectomy of the septum was performed using the Morrow method: despite the persisting SAM and increased LVOT gradients, the mitral valve was not replaced. The case study presents a conservative approach to mitral valve replacement during HCM surgery.

The role of imaging in the diagnosis and management of hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiomyopathy, affecting approximately 1:500 people. As the yield of genetic testing is only about 35-60%, the diagnosis of HCM is still clinical and based on the demonstration of unexplained and usually asymmetric left ventricular (LV) hypertrophy by imaging modalities. In the past, echocardiography was the sole imaging modality used for the diagnosis and management of HCM. However, in recent years other imaging modalities such as cardiac magnetic resonance have played a major role in the diagnosis, management and risk stratification of HCM, particularly when the location of left ventricular hypertrophy is atypical (apex, lateral wall) and when the echocardiographic imaging is sub-optimal. However, the most unique contribution of cardiac magnetic resonance is the quantification of myocardial fibrosis. Exercise stress echocardiography is the preferred provocative test for the assessment of LV outflow tract obstruction, which is detected only on provocation in one-third of the patients.