A Practical Approach to Echocardiographic Imaging in Patients With Hypertrophic Cardiomyopathy

doi:10.1016/j.echo.2023.04.020

Journal of the American Society of Echocardiography

Volume 36, Issue 9, September 2023, Pages 913-932

https://doi.org/10.1016/j.echo.2023.04.020 Get rights and content

Highlights

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Practical resources for developing HCM imaging protocols are discussed.
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Technical guidance for image and measurement acquisition in HCM patients is given.
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Sonographer worksheet tailored for HCM-specific echocardiographic exam is shown.

Hypertrophic cardiomyopathy (HCM) is frequently unrecognized or misdiagnosed. The recently published consensus recommendations from the American Society of Echocardiography provided recommendations for the utilization of multimodality imaging in the care of patients with HCM. This document provides an additional practical framework for optimal image and measurement acquisition and guidance on how to tailor the echocardiography examination for individuals with HCM. It also provides resources for physicians and sonographers to use to develop HCM imaging protocols.

Section snippets

Objective

Hypertrophic cardiomyopathy (HCM) is defined by the presence of left ventricular (LV) hypertrophy with a wall thickness in any segment ≥15 mm in the absence of other potentially causative cardiac, systemic, syndromic, or metabolic diseases associated with myocardial wall thickening.¹^,² It is a heterogeneous disease with variability in phenotype, clinical expression, hemodynamic profile, and prognosis. Despite a prevalence estimated from 1:500 to as high as 1:200, HCM is frequently unrecognized

Indications for Echocardiography in HCM

A comprehensive transthoracic echocardiogram (TTE),⁵ utilizing an HCM-specific protocol,¹^,²^,⁴ is recommended if there is suspicion for HCM such as in the following clinical scenarios:

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Survivor of a suspected HCM-related sudden cardiac arrest.
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Confirmed diagnosis of HCM in a first-degree relative.
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Symptoms suggestive of HCM including dyspnea or chest pain with exertion (often worse postprandially or with dehydration), palpitations, syncope/near-syncope.
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Systolic murmur suggestive of outflow

Goals of the Echocardiographic Examination for HCM

During the process of image acquisition, there are crucial data elements that must be integrated into the echo report given their importance in patient management:¹^,²^,4, 5, 6, 7, 8, 9

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LV wall thickness: accurate quantitation of the degree and location of maximal LV wall thickness is critical for diagnosis (≥15 mm or ≥13 mm with gene variant positivity or if present in a family member of a patient with HCM) and risk stratification. While HCM is often characterized by asymmetric septal

Technical Considerations for Performing TTE in HCM

The echocardiographic evaluation of a patient with known or suspected HCM should be comprehensive yet tailored to address the unique features of the individual patient. Table 1 provides guidance on key features of the echocardiographic protocol tailored for this patient population, and a sonographer worksheet specific for patients with HCM is provided as a Supplementary Table.

Practical Considerations for Stress Echocardiography in HCM

There are important differences in patient preparation for exercise testing in HCM in contrast to studies performed for ischemia evaluation. Exercise echocardiography has recognized limitations when employed for evaluation of epicardial obstructive coronary disease in patients with HCM.² The primary clinical utility of stress echocardiography in HCM is to identify occult LVOTO and dynamic MR, which may be responsible for effort-related symptoms in such individuals. Therefore, the stress echo

Considerations for Serial Echocardiography for Patients on Myosin Inhibitor Therapy

As noted previously, therapy with the novel cardiac myosin inhibitor, mavacamten, mandates regular echocardiographic imaging to guide dosing based on the LVOT gradient and to monitor for excessive reduction in LVEF. During the initiation phase of mavacamten therapy an echocardiogram is required every 4 weeks until week 12. The maintenance phase then requires an echocardiogram every 12 weeks indefinitely while on treatment. During this early experience with the use of mavacamten, some centers

Considerations for Echo Imaging After SRT

The 2020 American College of Cardiology/American Heart Association guidelines¹^,⁴ for the diagnosis and treatment of patients with HCM provide a class 1 recommendation for the performance of an echocardiogram 3 to 6 months after SRT. However, a limited predischarge examination should be performed if there is concern for complications including a ventricular septal defect, new or worsening aortic or MR, or a pericardial effusion. It is important to recognize the difference between an unroofed

Reporting

The following key features should be noted in the final impressions of a resting TTE report in a patient with HCM or concern for HCM:

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Left ventricular ejection fraction and LV size (based on indexed volume)
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Pattern of hypertrophy (basal septal, reverse septal curvature, apical, etc.)
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Site and severity of maximal wall thickness
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The presence, location, and severity of obstruction both at rest and with provocation
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The presence of an apical aneurysm (and presence of apical thrombus)
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Severity and

Conclusion

Hypertrophic cardiomyopathy is a common condition with a diverse phenotypic expression that all too often goes unrecognized or is misdiagnosed. Echocardiography plays a fundamental role in the diagnosis, risk stratification, and ultimately the management of patients with this disorder. Due to variable disease-specific manifestations and dynamic pathophysiology, HCM-specific echocardiographic imaging protocols are essential for comprehensive assessment under resting and exercise conditions. This

REVIEW STATEMENT

Given his role as Associate Editor, Sherif F. Nagueh, MD, FASE, had no involvement in the peer review of this article and has no access to information regarding its peer review. Full responsibility for the editorial process for this article was delegated to Rory B. Weiner, MD, FASE.

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Guidelines for performing a comprehensive transthoracic echocardiographic examination in adults: recommendations from the American Society of echocardiography
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There are more references available in the full text version of this article.

Cited by (4)

Septal Perforator Artery Doppler Flow in Hypertrophic Cardiomyopathy: Searching for Clinical Applicability
2024, Journal of the American Society of Echocardiography
Role of Imaging in the Diagnosis, Evaluation, and Management of Hypertrophic Cardiomyopathy
2024, American Journal of Cardiology
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.
Obstruction in Hypertrophic Cardiomyopathy: Many Faces
2024, Journal of the American Society of Echocardiography
Hypertrophic cardiomyopathy (HCM), the most common inherited cardiomyopathy, exhibits left ventricular hypertrophy not secondary to other causes, with varied phenotypic expression. Enhanced actin-myosin interaction underlies excessive myocardial contraction, frequently resulting in dynamic obstruction within the left ventricle. Left ventricular outflow tract obstruction, occurring at rest or with provocation in 75% of HCM patients, portends adverse prognosis, contributes to symptoms, and is frequently a therapeutic target. Transthoracic echocardiography plays a crucial role in the screening, initial diagnosis, management, and risk stratification of HCM. Herein, we explore echocardiographic evaluation of HCM, emphasizing Doppler assessment for obstruction. Echocardiography informs management strategies through noninvasive hemodynamic assessment, which is frequently obtained with various provocative maneuvers. Recognition of obstructive HCM phenotypes and associated anatomical abnormalities guides therapeutic decision-making. Doppler echocardiography allows monitoring of therapeutic responses, whether it be medical therapies (including cardiac myosin inhibitor therapy) or septal reduction therapies, including surgical myectomy and alcohol septal ablation. This article discusses the hemodynamics of obstruction and practical application of Doppler assessment in HCM. In addition, it provides a visual atlas of obstruction in HCM, including high-quality figures and complementary videos that illustrate the many facets of dynamic obstruction.
Real-world experience with mavacamten in obstructive hypertrophic cardiomyopathy: Observations from a tertiary care center
2024, Progress in Cardiovascular Diseases
In symptomatic obstructive hypertrophic cardiomyopathy (oHCM) patients, mavacamten is commercially approved to help improve left ventricular (LV) outflow tract (LVOT) gradients, symptoms, and reduce eligibility for septal reduction therapy (SRT) under the risk evaluation and mitigation strategy (REMS) program. We sought to prospectively report the initial real-world clinical experience with the use of commercially available mavacamten in a multi-hospital tertiary healthcare system.
We studied the first 150 consecutive oHCM patients (mean age 65 years, 53% women, 83% on betablockers and 61% in New York Heart Association [NYHA] class III) who were initiated on 5 mg of mavacamten with dose titrations using symptom assessment and echocardiographic measurements of LVOT gradient and LV ejection fraction (LVEF) measurements. We measured changes in NYHA class, LVEF, LVOT gradients (resting and Valsalva) at baseline, 4, 8 and 12 weeks.
At 261 ± 143 days (range of 31–571 days), 69 (46%) patients had ≥1 NYHA class, and 27 (18%) additional patients had ≥2 NYHA class improvement. The mean Valsalva LVOT gradient decreased from 72 ± 43 mmHg at baseline to 29 ± 31 mmHg at 4 weeks, 29 ± 28 mmHg at 8 weeks and 30 ± 29 mmHg at 12 weeks (p < 0.001). At baseline, 100% patients had Valsalva LVOT gradients ≥30 mmHg, which reduced to 29% at 4 weeks, 28% at 8 weeks and 30% at 12 weeks. In 40 patients who reported no symptomatic improvement, the mean Valsalva LVOT gradient decreased from 73 ± 39 mmHg at baseline to 34 ± 27 mmHg at 4 weeks, 35 ± 28 mmHg at 8 weeks and 30 ± 24 mmHg at 12 weeks (P < 0.001). The mean LVEF at baseline was 66 ± 6% and changed to 64 ± 5% at 4 weeks, 63 ± 5% at 8 weeks and 62 ± 7% at 12 weeks (p < 0.0001). No patient underwent SRT, developed LVEF ≤30% or developed heart failure requiring admission. Three (2%) patients needed temporary interruption of mavacamten due to LVEF<50%.
In a real-world study in symptomatic oHCM patients at a multi-hospital tertiary care referral center, we demonstrate the efficacy and safety, along with the logistic feasibility of prescribing mavacamten under the REMS program.

: Conflicts of Interest: C.C.M. has authored textbook chapters for Elsevier and is the recipient of a W. L. Gore & Associates contracted research grant to the University of Wisconsin–Madison. M.J. is a consultant for Caption Health, is a consultant for and has received an honorarium from Bristol Myers Squibb, and is on the advisory board of Echo IQ. J.S. has received research support from Bristol Myers Squibb, Cytokinetics, Imbria Pharmaceuticals, and CorVista Health. T.A. has no financial conflicts but is a site investigator, steering committee member, or publications committee member for trials sponsored by Bristol Myers Squibb, Cytokinetics, and Tenaya Pharmaceuticals. M.D. is a consultant for Bristol Myers Squibb, Cytokinetics, and Medtronic. M.W.M. receives financial support from Bristol Myers Squibb, Cytokinetics, and Major League Soccer. D.P. is a consultant for Caption Health and a speaker for Pfizer and Bristol Myers Squibb. The remaining authors have no conflicts to report.

: Rory B. Weiner, MD, FASE, served as guest editor for this report.

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2023 by the American Society of Echocardiography.

Imaging StrategiesA Practical Approach to Echocardiographic Imaging in Patients With Hypertrophic Cardiomyopathy

Highlights

Section snippets

Objective

Indications for Echocardiography in HCM

Goals of the Echocardiographic Examination for HCM

Technical Considerations for Performing TTE in HCM

Practical Considerations for Stress Echocardiography in HCM

Considerations for Serial Echocardiography for Patients on Myosin Inhibitor Therapy

Considerations for Echo Imaging After SRT

Reporting

Conclusion

REVIEW STATEMENT

J Am Soc Echocardiogr

Am J Cardiol

J Am Soc Echocardiogr

J Am Soc Echocardiogr

J Am Soc Echocardiogr

J Am Soc Echocardiogr

J Am Soc Echocardiogr

Imaging Strategies
A Practical Approach to Echocardiographic Imaging in Patients With Hypertrophic Cardiomyopathy