A Practical Approach to Echocardiographic Imaging in Patients With Hypertrophic Cardiomyopathy

ANMCO position paper 'Hypertrophic cardiomyopathy: from diagnosis to treatment'

Hypertrophic cardiomyopathy (HCM) is a non-rare genetic cardiomyopathy, with an estimated prevalence of 1:500, characterized by an increase in the left ventricular wall thickness in the absence of increased loading conditions. The hypertrophy is mostly asymmetric and predominantly affects the basal septum and anterior wall. Left ventricular outflow tract obstruction, at rest or after provocative tests, is detected in many patients and represents the primary cause of reduced functional capacity, as well as an independent predictor of sudden cardiac death and advanced heart failure. Until ∼1 year ago, symptomatic patients despite maximal therapy with β-blockers or calcium channel blockers plus disopyramide had only basal septal reduction therapy through myectomy or septal alcoholization as additional therapeutic options. Today, a new class of drugs that inhibit cardiac myosin activity is available for patients with obstructive HCM. In light of the new treatment perspectives, the correct clinical-therapeutic classification of affected patients becomes of fundamental importance for the cardiologist. The aim of this position paper is to increase the knowledge of cardiologists in the field of HCM, defining its epidemiological, genetic, and pathological characteristics, identifying the diagnostic criteria and instrumental methods capable of stratifying the risk profile, with the aim of an optimal therapy tailored on the single patient.

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.

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.

Real-world experience with mavacamten in obstructive hypertrophic cardiomyopathy: Observations from a tertiary care center

BACKGROUND

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.

METHODS

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.

RESULTS

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%.

CONCLUSIONS

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.

Mid-Ventricular Obliteration Diagnosed by Bedside-Focused Echocardiography in the Emergency Department in a Patient With Syncope and Associated Hypertrophic Cardiomyopathy: A Case Report

Syncope is a common complaint encountered in emergency medicine practice with multiple potential etiologies to investigate. The utility of focused bedside echocardiography allows emergency physicians to diagnose acute cardiovascular causes in a time-sensitive fashion. In this case report, a 61-year-old female with mixed aortic valve disease presented to the emergency department after a syncopal episode. In addition to standard electrocardiogram and laboratory testing, investigation with focused echocardiography performed at the point of care revealed mid-ventricular obliteration due to hypertrophic myocardial remodeling, left ventricular underfilling, and hyperdynamic performance. Key echocardiographic findings that may assist emergency physicians in recognizing and managing this physiological entity were discussed.

Obstruction in Hypertrophic Cardiomyopathy: Many Faces

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.

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.