Complementary Role of Echocardiography and Cardiac Magnetic Resonance in Hypertrophic Cardiomyopathy

Importance of T1-Mapping Sequence in Patients with Hypertrophic Cardiomyopathy without Foci of Non-Ischemic Myocardial Injury in Late Gadolinium Enhancement Sequence

BACKGROUND

The aim of this study was to assess the importance of T1-mapping sequences in the diagnosis of hypertrophic cardiomyopathy (HCM) in patients without foci of non-ischemic myocardial injury in classic cardiac magnetic resonance (CMR) sequences.

METHODS

Two groups were compared: 28 patients with HCM, without any foci of myocardial injury in the late gadolinium enhancement (LGE) sequence (HCM group), and 28 patients without cardiomyopathy (CON group). Classic CMR sequences and T1-mapping sequences were performed. The following parameters were assessed: T1 time of the whole left ventricular myocardium, T1 time of myocardium in the basal, middle and apical layers of the left ventricle, and T1 time in individual segments of the left ventricular myocardium. Myocardial extracellular volume (ECV) was assessed similarly.

RESULTS

ECV was significantly higher in the HCM group than in the CON group, for the whole left ventricular myocardium, for the basal and apical layers of the left ventricle, and for segments 1-3, 8, and 13-16 of the left ventricle. Regression analysis showed that a higher left-ventricular mass index (LVMI), a higher body mass index and older age are factors independently associated with a higher ECV of the whole myocardium but only in the group with LVMI ≥ 131.84 g/m2.

CONCLUSION

In patients with HCM without foci of non-ischemic myocardial injury, higher ECV values of the left ventricular myocardium are observed.

Current use of cardiac MRI in animals

Cardiovascular magnetic resonance (CMR) imaging has evolved to become an indispensable tool in human cardiology. It is a non-invasive technique that enables objective assessment of myocardial function, size, and tissue composition. Recent innovations in magnetic resonance imaging scanner technology and parallel imaging techniques have facilitated the generation of parametric mapping to explore tissue characteristics, and the emergence of strain imaging has enabled cardiologists to evaluate cardiac function beyond conventional metrics. As veterinary cardiology continues to utilize CMR beyond the reference standard, clinical application of CMR will further expand our capabilities. This article describes the current use of CMR and adoption of more recent advances such as T1/T2 mapping in veterinary cardiology.

Detecting Regional Fibrosis in Hypertrophic Cardiomyopathy: The Utility of Myocardial Strain Based on Cardiac Magnetic Resonance

RATIONALE AND OBJECTIVES

The value of myocardial strain for reflecting fibrosis in patients with hypertrophic cardiomyopathy (HCM) on cardiac magnetic resonance (CMR) has not been definite. We aim to explore whether there are underlying non-contrast parameters to evaluate myocardial fibrosis and screen which may be the best.

MATERIALS AND METHODS

We retrospectively included 127 HCM patients (89 men; average age 46.6 ± 15.6 years) and 30 healthy controls (20 men; average age 52.0 ± 13.2 years) who have undergone late gadolinium enhancement (LGE) CMR. Next, 127 HCM patients were divided randomly into two sets including training cohort and validation cohort. Strain and imaging parameters were measured and analyzed statistically.

RESULTS

Based on univariate and multivariate analysis, segmental circumferential strain (SCS) (p < 0.001) and maximal wall thickness (MWT) (p < 0.001) may differentiate myocardial segments with or without LGE as significant biomarkers for both sets. The area under the curve (AUC) was 0.803 (95% CI 0.785-0.820) for SCS and 0.777 (95% CI 0.759-0.795) for MWT to identify myocardial fibrosis. When combining SCS >-13.9% and MWT >16.4mm, the specificity of the model (AUC = 0.779; 95% CI 0.760-0.796) achieved the highest 93.9%, with a sensitivity of 61.8%.

CONCLUSION

Strain analysis in HCM holds promise for myocardial fibrosis detection and SCS is the best strain parameter based on CMR. Nevertheless, the model of combining SCS and MWT could achieve the highest specificity for fibrotic diagnosis.

Evaluation of Left Ventricular Mass in Different Cardiac Geometry Using Three-Dimensional Contrast-Enhanced Echocardiography

A total of 69 patients were enrolled in the study, including 23 patients with hypertrophic cardiomyopathy (HCM), 26 patients with Left Ventricle (LV) enlargement comprising 16 dilated cardiomyopathy (DCM) patients and 10 ischemic cardiomyopathy (ICM) patients, and 20 control subjects. All patients underwent 2DE, contrast-enhanced 2DE (Contrast-2DE), 3DE, Contrast-3DE, and single photon emission computed tomography (SPECT) examinations. The 2DE-AL and 3DE methods measured the left ventricular mass (LVM). The results were compared with those measured by SPECT. The measured LVM of the 69 patients was systematically overestimated by 2DE-AL (177.4 ± 56.2 g), Contrast-2DE-AL (174.5 ± 55.5 g), 3DE (167.3 ± 59.2 g), and Contrast-3DE (154.2 ± 46.7 g) when compared with SPECT (148.5 ± 52.4 g) (P < 0.05), while Contrast-3DE provided the best agreement with SPECT in LVM measurement (r = 0.898, P < 0.001) and had the smallest deviation (5.7 ± 23.1 g). 3DE overestimated LVM more compared to Contrast-3DE in LV hypertrophy group (165.5 ± 37.9 g versus 153.5 ± 27.6 g, P = 0.003) and LV enlargement group (204.5 ± 69.3 g versus 183.5 ± 53.5 g, P = 0.006). For 2DE methods, there was no significant difference between the LVM obtained with or without contrast enhancement in control group (132.3 ± 23.6 g versus 128.4 ± 23.3 g), LV hypertrophy group (177.7 ± 38.6 versus 178.3 ± 30.9 g, P = 0.889), and LV enlargement group (211.9 ± 63.2 g versus 206.5 ± 66.0 g, P = 0.386). The difference between LVM measured by 2DE-AL and SPECT was the greatest (27.9 ± 34.0 g), especially in LV hypertrophy group and LV enlargement group (LV hypertrophy group 39.7 ± 26.0 g; LV enlargement group 24.2 ± 42.8 g). To conclude, Contrast-3DE and SPECT show greater consistency in LVM measurement, especially in cardiomyopathy, when compared with 2DE. Administering contrast can effectively reduce the overestimation of LVM by non-contrast DE.

Cardiovascular Imaging in Pregnancy: Valvulopathy, Hypertrophic Cardiomyopathy, and Aortopathy

Pregnancy is associated with profound hemodynamic changes that are particularly impactful in patients with underlying cardiovascular disease. Management of pregnant women with cardiovascular disease requires careful evaluation that considers the well-being of both the woman and the developing fetus. Clinical assessment begins before pregnancy and continues throughout gestation into the post-partum period and is supplemented by cardiac imaging. This review discusses the role of imaging, specifically echocardiography, cardiac MRI, and cardiac CT, in pregnant women with valvular diseases, hypertrophic cardiomyopathy, and aortic pathology.

Recommendations for Multimodality Cardiovascular Imaging of Patients with Hypertrophic Cardiomyopathy: An Update from the American Society of Echocardiography, in Collaboration with the American Society of Nuclear Cardiology, the Society for Cardiovascular Magnetic Resonance, and the Society of Cardiovascular Computed Tomography

Hypertrophic cardiomyopathy (HCM) is defined by the presence of left ventricular hypertrophy in the absence of other potentially causative cardiac, systemic, syndromic, or metabolic diseases. Symptoms can be related to a range of pathophysiologic mechanisms including left ventricular outflow tract obstruction with or without significant mitral regurgitation, diastolic dysfunction with heart failure with preserved and heart failure with reduced ejection fraction, autonomic dysfunction, ischemia, and arrhythmias. Appropriate understanding and utilization of multimodality imaging is fundamental to accurate diagnosis as well as longitudinal care of patients with HCM. Resting and stress imaging provide comprehensive and complementary information to help clarify mechanism(s) responsible for symptoms such that appropriate and timely treatment strategies may be implemented. Advanced imaging is relied upon to guide certain treatment options including septal reduction therapy and mitral valve repair. Using both clinical and imaging parameters, enhanced algorithms for sudden cardiac death risk stratification facilitate selection of HCM patients most likely to benefit from implantable cardioverter-defibrillators.

Anatomical-MRI Correlations in Adults and Children with Hypertrophic Cardiomyopathy

Hypertrophic Cardiomyopathy (HCM) is the most frequent hereditary cardiovascular disease and the leading cause of sudden cardiac death in young individuals. Advancements in CMR imaging have allowed for earlier identification and more accurate prognosis of HCM. Interventions aimed at slowing or stopping the disease’s natural course may be developed in the future. CMR has been validated as a technique with high sensitivity and specificity, very few contraindications, a low risk of side effects, and is overall a good tool to be employed in the management of HCM patients. The goal of this review is to evaluate the magnetic resonance features of HCM, starting with distinct phenotypic variants of the disease and progressing to differential diagnoses of athlete’s heart, hypertension, and infiltrative cardiomyopathies. HCM in children has its own section in this review, with possible risk factors that are distinct from those in adults; delayed enhancement in children may play a role in risk stratification in HCM. Finally, a number of teaching points for general cardiologists who recommend CMR for patients with HCM will be presented.

Screening for hypertrophic cardiomyopathy

ABSTRACT

Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiomyopathy and causes changes in the cardiac muscle affecting ventricular, valvular, and cellular functions. Because HCM is an inherited disorder, all age groups are affected; however, it commonly presents in adolescents, especially athletes. Many patients are asymptomatic and undiagnosed, putting them at risk for sudden cardiac death. This article describes screening and management of patients with HCM.

Efficacy of Novel Noncontrast Cardiac Magnetic Resonance Methods in Indicating Fibrosis in Hypertrophic Cardiomyopathy

Objective

In hypertrophic cardiomyopathy (HCM), myocardial fibrosis is routinely shown by late gadolinium enhancement (LGE) in cardiac magnetic resonance (CMR) imaging. We evaluated the efficacy of 2 novel contrast-free CMR methods, namely, diffusion-weighted imaging (DWI) and feature-tracking (FT) method, in detecting myocardial fibrosis.

Methods

This cross-sectional study was conducted on 26 patients with HCM. Visual and quantitative comparisons were made between DWI and LGE images. Regional longitudinal, circumferential, and radial strains were compared between LGE-positive and LGE-negative segments. Moreover, global strains were compared between LGE-positive and LGE-negative patients as well as between patients with mild and marked LGE.

Results

All 3 strains showed significant differences between LGE-positive and LGE-negative segments (P < 0.001). The regional longitudinal and circumferential strain parameters showed significant associations with LGE (P < 0.001), while regional circumferential strain was the only independent predictor of LGE in logistic regression models (OR: 1.140, 95% CI: 1.073 to 1.207, P < 0.001). A comparison of global strains between patients with LGE percentages of below 15% and above 15% demonstrated that global circumferential strain was the only parameter to show impairment in the group with marked myocardial fibrosis, with borderline significance (P=0.09). A review of 212 segments demonstrated a qualitative visual agreement between DWI and LGE in 193 segments (91%). The mean apparent diffusion coefficient was comparable between LGE-positive and LGE-negative segments (P=0.51).

Conclusions

FT-CMR, especially regional circumferential strain, can reliably show fibrosis-containing segments in HCM. Further, DWI can function as an efficient qualitative method for the estimation of the fibrosis extent in HCM.

Segmental longitudinal strain as the most accurate predictor of the patchy pattern late gadolinium enhancement in hypertrophic cardiomyopathy

BACKGROUND

The prognostic value of myocardial fibrosis in patients with hypertrophic cardiomyopathy (HCM) has been well-established. Although cardiac magnetic resonance (CMR) is the method of choice in its revealing as the presence of late gadolinium enhancement (LGE), this technique still has limited availability in daily clinical practice. Two-dimensional speckle tracking echocardiography (2D STE) seems to be helpful in verification which HCM patient has the highest probability of LGE presence and hence needs to be qualified to CMR. While the majority of HCM patients have a patchy pattern of myocardial fibrosis, the aim of this study was to evaluate whether segmental rather than global longitudinal strain is more accurate in the identification of the presence of LGE.

METHODS

Forty-six HCM patients had transthoracic echocardiography and CMR imaging performed. Each patient had global longitudinal strain and rotation parameters calculated, as well as segmental analyses for wall thickness, longitudinal strain, and LGE presence based on 736 segments of the left ventricle (LV). The presence of LGE in CMR was confirmed on a per-segment basis, which was similar to LV segments in the echocardiographic examination. All patients were divided into two groups according to the CMR result: LGE (+) and LGE (-).

RESULTS

Receiver-operating characteristic analyses identified peak global longitudinal strain and peak twisting velocity with the cut-off values -14.4% and 116°/s respectively as the accurate predictors of LGE presence in CMR, whereas segmental longitudinal strain of -12.5% cut-off value had the highest area under the curve value (87.4%, confidence interval 84.5-90.3%), with 93.7% sensitivity, 86.5% negative predictive value, and 55% specificity.

CONCLUSIONS

Segmental longitudinal strain with the cut-off value of -12.5% has the highest discriminatory power for LGE presence and seems to be more adequate than global speckle tracking parameters in identification of HCM patients with strong indications for CMR for more accurate risk stratification.

Prevalence of Unexplained Left Ventricular Hypertrophy by Cardiac Magnetic Resonance Imaging in MESA

Background

Hypertrophic cardiomyopathy is defined as unexplained left ventricular (LV) hypertrophy (wall thickness ≥15 mm) and is prevalent in 0.2% of adults (1:500) in population‐based studies using echocardiography. Cardiac magnetic resonance imaging (MRI) allows for more accurate wall thickness measurement across the entire ventricle than echocardiography. The prevalence of unexplained LV hypertrophy by cardiac MRI is unknown. MESA (Multi‐Ethnic Study of Atherosclerosis) recruited individuals without overt cardiovascular disease 45 to 84 years of age.

Methods and Results

We studied 4972 individuals who underwent measurement of regional LV wall thickness by cardiac MRI as part of the MESA baseline exam. American Heart Association criteria were used to define LV segments. We excluded participants with hypertension, LV dilation (≥95% predicted end‐diastolic volume) or dysfunction (ejection fraction ≤50%), moderate‐to‐severe left‐sided valve lesions by cardiac MRI, severe aortic valve calcification by cardiac computed tomography (aortic valve Agatston calcium score >1200 in women or >2000 in men), obesity (body mass index >35 kg/m²), diabetes mellitus, and current smoking. Sixty‐seven participants (aged 64±10 years, 9% female) had unexplained LV hypertrophy (wall thickness ≥15 mm in at least 2 adjacent LV segments), representing 1.4% (1 in 74) participants, 2.6% of men and 0.2% of women. Prevalence was similar across categories of race/ethnicity. Hypertrophy was focal in 17 (25.4%), intermediate in 44 (65.7%), and diffuse in 5 (7.5%) participants.

Conclusions

The prevalence of unexplained LV hypertrophy in a population‐based cohort using cardiac MRI was 1.4%. This may have implications for the diagnosis of patients with hypertrophic cardiomyopathy and will require further study.

Whole-genome DNA sequencing: The key to detecting a sarcomeric mutation in a 'false genotype-negative' family with hypertrophic cardiomyopathy

The authors report the clinical and genetic investigation of a family with hypertrophic cardiomyopathy (HCM). The individuals described are three affected first-degree relatives (father, daughter and son), one affected niece and unaffected nephew and niece. Those affected all share a very similar phenotype consisting of asymmetric HCM, with hypertrophy particularly affecting the septum and the anterior wall, and similar electrocardiographic features, including a short PR interval. Case 1 (proband) presented with obstructive HCM and had undergone myectomy and mitral valve replacement. Case 2 (oldest offspring of Case 1) had non-obstructive HCM with exertional angina and NYHA II heart failure (HF) symptoms; she developed non-sustained ventricular tachycardia during follow-up and received a single-chamber ICD for primary prevention of sudden cardiac death. Case 3 (son of case 1) presented with asymptomatic non-obstructive HCM and developed NYHA II HF symptoms during follow-up. Case 4 had non-obstructive HCM, mainly with NYHA II HF symptoms. Testing of the proband for sarcomeric mutations and phenocopies was initially negative. After eight years of clinical follow-up, the suspicion of an undiscovered pathogenic gene mutation shared among the members of this family led us to enroll the proband in a whole-genome sequencing research project, which revealed a heterozygous pathogenic intronic MYBPC3 variant (c.1227-13G>A [rs397515893]), cosegregating with the phenotype.

Is there a role for cardiac positron emission tomography in hypertrophic cardiomyopathy?

Coronary microvascular dysfunction and, its functional consequence, myocardial ischemia are common pathologic features in patients with hypertrophic cardiomyopathy (HCM). Both have been commonly invoked as potential triggers of and/or contributors to the underlying pathophysiological processes leading to heart failure, and malignant ventricular arrhythmias. Positron emission tomography (PET) with myocardial blood flow quantification provides a unique opportunity to evaluate the integrity and function of the coronary microcirculation in HCM. The purpose of the present review is to summarize all the pertinent literature and future perspectives of the role of PET in the evaluation and risk stratification of patients with HCM.